WO2024095930A1 - Heat-insulating material - Google Patents

Heat-insulating material Download PDF

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Publication number
WO2024095930A1
WO2024095930A1 PCT/JP2023/038971 JP2023038971W WO2024095930A1 WO 2024095930 A1 WO2024095930 A1 WO 2024095930A1 JP 2023038971 W JP2023038971 W JP 2023038971W WO 2024095930 A1 WO2024095930 A1 WO 2024095930A1
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Prior art keywords
formula
layer
heat insulating
mpa
buffer layer
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PCT/JP2023/038971
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French (fr)
Japanese (ja)
Inventor
集 佐々木
丈裕 宇井
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日東電工株式会社
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Publication of WO2024095930A1 publication Critical patent/WO2024095930A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/022—Mechanical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/027—Thermal properties
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/71—Ceramic products containing macroscopic reinforcing agents
    • C04B35/78—Ceramic products containing macroscopic reinforcing agents containing non-metallic materials
    • C04B35/80—Fibres, filaments, whiskers, platelets, or the like
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L59/00—Thermal insulation in general
    • F16L59/02—Shape or form of insulating materials, with or without coverings integral with the insulating materials
    • F16L59/021—Shape or form of insulating materials, with or without coverings integral with the insulating materials comprising a single piece or sleeve, e.g. split sleeve, two half sleeves
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/64—Heating or cooling; Temperature control characterised by the shape of the cells
    • H01M10/647—Prismatic or flat cells, e.g. pouch cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/60—Heating or cooling; Temperature control
    • H01M10/65—Means for temperature control structurally associated with the cells
    • H01M10/658—Means for temperature control structurally associated with the cells by thermal insulation or shielding

Definitions

  • the present invention relates to a thermal insulation material, and more particularly to a thermal insulation material having a thermal insulation layer and a buffer layer.
  • Non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries are increasingly being used as power sources for electrically powered vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PEVs), and fuel cell vehicles (FCVs). Because these applications require extremely high output and capacity, they are used in the form of battery modules or battery packs that integrate battery cells (single cells). In addition, in order to ensure safety, etc., it is being considered to use components with various functions in lithium-ion secondary battery battery packs. For example, insulating materials are being placed between cells to prevent thermal runaway even if some cells become abnormally hot.
  • Non-Patent Document 1 describes that the cause is an oxide coating caused by a side reaction between silicon particles and the electrolyte, etc., and as a countermeasure, a new anti-oxidation coating is used to suppress the irreversible expansion of the material, thereby suppressing both electrode expansion and cycle deterioration.
  • Non-Patent Document 2 discloses that the use of a binder with an adjusted elastic modulus suppresses electrode expansion and improves cycle characteristics.
  • Patent Document 1 also discloses that the elastic body, which receives a load from the electrode body of the secondary battery in the stacking direction of the electrode body, also plays a role in absorbing pressure, and that by specifying the compressive elastic modulus of each member, it is possible to suppress the increase in resistance during high-rate charging and discharging and the decrease in capacity during charge and discharge cycles.
  • the insulating material arranged between the cells of a battery pack or the like has insulating properties to suppress thermal runaway, etc., can change its thickness accordingly in response to repeated expansion and contraction of the cells, and has cushioning properties that can generate appropriate stress.
  • the present invention aims to provide an insulating material that has excellent heat insulation and shock-absorbing properties, particularly suitable for use as an insulating material placed between cells of a battery pack, etc.
  • the heat insulating material provided by this specification has a heat insulating layer containing inorganic particles, and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam.
  • the buffer layer is a layer that can generate a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min.
  • the buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b2-1) and (b2-2) when the compression test is performed.
  • the buffer layer is a layer that can generate the above compressed state, it becomes easier to ensure suitable cushioning properties.
  • the buffer layer is a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b3-1) and (b3-2) when the compression test is performed. If the buffer layer is a layer that can generate the above compressed state, more suitable cushioning properties can be easily ensured.
  • Formula (b3-1) 1.50 ⁇ y B ⁇ 3.00
  • the buffer layer is a layer that, when the compression test is performed, generates a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b4-1) and formula (b4-2):
  • the buffer layer is a layer that can generate the above compressed state, it becomes easier to ensure more suitable cushioning properties.
  • Formula (b4-1) 2.00 ⁇ y B ⁇ 2.50
  • the thermal insulation layer is preferably a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a1-1) and formula (a1-2) when a compression test is performed on the thermal insulation layer alone at a compression speed of 0.5 mm/min.
  • the thermal insulation material can exhibit suitable thermal insulation and cushioning properties.
  • the heat insulating layer is more preferably a layer that can generate a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a2-1) and formula (a2-2) when the compression test is performed.
  • the heat insulating layer is a layer that can generate the above compressed state, better heat insulation is more easily ensured.
  • the heat insulating layer is a layer that can generate a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a3-1) and formula (a3-2) when the compression test is performed. If the heat insulating layer is a layer that can generate the above compressed state, it becomes easier to ensure even better heat insulation.
  • Formula (a3-2) 0.20xA -1.50 ⁇ yA
  • the insulating layer is preferably a layer containing silicon dioxide particles as the inorganic particles.
  • the insulating material disclosed herein can be preferably implemented in a configuration including an insulating layer containing silicon dioxide particles and the buffer layer.
  • the silicon dioxide particles at least one type selected from the group consisting of dry silica, wet silica, and silica aerogel can be preferably used.
  • the dry silica is hydrophilic fumed silica.
  • the insulating layer is preferably a molded body formed from a mixture containing the inorganic particles and inorganic fibers.
  • the insulating material disclosed herein can be preferably implemented in a configuration including an insulating layer that is such a molded body and the buffer layer.
  • the insulating material disclosed herein can be preferably used in a form in which it is disposed between the cells of a battery module. It is particularly suitable as an insulating material disposed between the cells of a lithium-ion battery module.
  • FIG. 1 is a graph showing a stress-strain curve (SS curve) when a compression test is performed on only the buffer layer, and a region of compressive strain value x B [%] and compressive stress value y B [MPa] that satisfies formulas (b1-1) and (b1-2).
  • FIG. 1 is a perspective view showing a schematic diagram of an example of a battery module in which an insulating material according to one embodiment is disposed between cells.
  • FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2.
  • FIG. 1 is a perspective view showing a schematic diagram of an insulating material according to one embodiment. 4 is a cross-sectional view taken along line IV-IV of FIG.
  • SS curve stress-strain curve
  • FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment.
  • FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment.
  • FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment.
  • 1 is a stress-strain curve (SS curve) of the insulating layer A.
  • 1 is a stress-strain curve (SS curve) of the insulating layer B.
  • 1 is a stress-strain curve (SS curve) of the insulating layer C.
  • 4 shows the stress-strain curves (SS curves) of the insulating layers D and E.
  • SS curves stress-strain curves of the insulating layers F, G, and H.
  • 1 is a stress-strain curve (SS curve) of the insulating layer I.
  • 1 shows stress-strain curves (SS curves) of the insulating layers J and K.
  • 1 is a stress-strain curve (SS curve) of the buffer layer A.
  • 1 is a stress-strain curve (SS curve) of the buffer layer B.
  • SS curve stress-strain curve (SS curve) of the buffer layer C.
  • SS curve stress-strain curve (SS curve) of the buffer layer D.
  • 1 is a stress-strain curve (SS curve) of the buffer layer E.
  • 1 is a stress-strain curve (SS curve) of the buffer layer F.
  • 1 shows stress-strain curves (SS curves) of the buffer layers G and I.
  • 1 shows stress-strain curves (SS curves) of buffer layers H and J.
  • 2 is a stress-strain curve (SS curve) of the buffer layer M.
  • 1 shows stress-strain curves (SS curves) of buffer layers K, N, and O.
  • 2 shows stress-strain curves (SS curves) of the buffer layers L and P.
  • 1 shows stress-strain curves (SS curves) of the buffer layers Q and T.
  • 1 shows stress-strain curves (SS curves) of the buffer layers R and S. 1 shows stress-strain curves (SS curves) of the buffer layers U, V, and W.
  • 1 shows stress-strain curves (SS curves) of the buffer layers X and Y.
  • 1 is a stress-strain curve (SS curve) of the buffer layer Z.
  • 1 is a stress-strain curve (S-S curve) that shows a schematic diagram of loading-unloading test 1 (high pressure condition).
  • 1 is a stress-strain curve (S-S curve) showing a schematic diagram of loading-unloading test 2 (low pressure condition).
  • the heat insulating material (hereinafter sometimes abbreviated as “heat insulating material”) disclosed in this specification has a heat insulating layer (hereinafter sometimes abbreviated as “heat insulating layer”) containing inorganic particles, and a buffer layer (hereinafter sometimes abbreviated as “buffer layer”) consisting of a fiber molded body containing fibers or a foam molded body containing a foam.
  • the thermal insulation material is characterized in that the buffer layer is a layer that can produce a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min.
  • Formula (b1-1) 0.50 ⁇ y B ⁇ 3.45
  • the buffer layer is a layer that can produce a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min.
  • Formula (b5-1) 0.10 ⁇ y B ⁇ 1.39
  • the inventors discovered that by providing a cushioning layer made of a fiber molded body containing fibers or a foamed molded body containing foam in addition to the insulating layer, and by using a layer that can produce a specific compression state in a compression test as the cushioning layer, it is possible to obtain an insulating material whose thickness changes appropriately in response to repeated cell expansion and contraction, and which generates an appropriate stress.
  • compression test refers to a test in which a compressive force (load) is applied to a test object, and the compressive strength, etc. of the test object is measured until the test object is deformed or broken.
  • the compression test can be appropriately performed using a commercially available testing machine such as a precision universal testing machine Autograph. With these testing machines and control software, the “compression speed” can be set as a test condition, and generally, the compressive displacement and compressive strength of the test object are measured sequentially as the test object is compressed, and “compressive strain,” “compressive stress,” stress-strain curves (S-S curves), etc. are automatically output.
  • the insulation material disclosed in this specification includes an insulation layer and a buffer layer, but the compression test itself is considered to be a standalone test in which the buffer layer alone or the insulation layer alone is the test object.
  • the buffer layer in the thermal insulation material is a "layer in which a compressed state of compressive strain value x B [%] and compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) can be generated when the above-mentioned compression test is performed.
  • the buffer layer has values that simultaneously satisfy the following formulas (b1-1) and (b1-2) for "compressive strain value x B [%]” and the corresponding "compressive stress value y B [MPa]” in the compressed state generated by the above-mentioned compression test.
  • Formula (b1-1) 0.50 ⁇ y B ⁇ 3.45
  • formula (b1-1) represents the inside of two straight lines parallel to the x-axis in Fig. 1
  • formula (b1-2) represents the inside of two straight lines extending diagonally in Fig. 1
  • the compressive strain value xB and compressive stress value yB that simultaneously satisfy formula (b1-1) and formula (b1-2) are present in the region surrounded by these straight lines (hereinafter also referred to as region (b1)).
  • a layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formula (b1-1) and formula (b1-2) can occur can be said to be a layer in which at least one combination of compressive strain value xB and compressive stress value yB obtained by a compression test belongs to this region (b1). Furthermore, even if there is no combination that falls within region (b1) as a specific measured value in a compression test, if an approximation curve of compressive strain value xB and compressive stress value yB passes through region (b1), the layer can be considered to belong to region (b1).
  • a "layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formulas (b1-1) and (b1-2) can occur” can be said to be a layer in which the so-called “stress-strain curve (S-S curve)" obtained by a compression test passes through region (b1).
  • the buffer layer is preferably a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b2-1) and (b2-2) when the above-mentioned compression test is carried out.
  • the stress-strain curve obtained by the above-mentioned compression test passes through the region enclosed by formulae (b2-1) and (b2-2) (region (b2)).
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the left side of formula (b2-2) "0.20x B -11.00” represents a straight line connecting the point where the compressive strain value is “60%” and the compressive stress value is “1.00 MPa” and the point where the compressive strain value is “70%” and the compressive stress value is “3.00 MPa”, and the slope "0.20” and the intercept "-11.00” are calculated from these points.
  • the buffer layer is preferably a layer that can generate a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b3-1) and (b3-2) when the above-mentioned compression test is carried out.
  • Formula (b3-1) 1.50 ⁇ y B ⁇ 3.00
  • Formula (b3-2) 0.15x B -7.50 ⁇ y B ⁇ 0.10x B -1.00
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the left side of formula (b3-2) "0.15x B -7.50” represents a straight line connecting the point where the compressive strain value is “60%” and the compressive stress value is "1.50 MPa” and the point where the compressive strain value is “70%” and the compressive stress value is “3.00 MPa”, and the slope "0.15" and the intercept "-7.50” are calculated from these points.
  • the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b4-1) and (b4-2) when the above-mentioned compression test is carried out.
  • Formula (b4-1) 2.00 ⁇ y B ⁇ 2.50
  • Formula (b4-2) 0.10x B -3.50 ⁇ y B ⁇ 0.10x B -1.50
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the left side of formula (b4-2) "0.10x B -3.50” represents a straight line connecting the point where the compressive strain value is “55%” and the compressive stress value is "2.00 MPa” and the point where the compressive strain value is "60%” and the compressive stress value is "2.50 MPa”, and the slope "0.10” and the intercept "-3.50” are calculated from these points.
  • the buffer layer in the thermal insulation material may be "a layer in which a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) can be generated when the above-mentioned compression test is performed.
  • the buffer layer has values that simultaneously satisfy the following formula (b5-1) and formula (b5-2) as the “compressive strain value x B [%]” and the corresponding "compressive stress value y B [MPa]” in the compressed state generated by the above-mentioned compression test.
  • Formula (b5-1) 0.10 ⁇ y B ⁇ 1.39
  • formula (b5-1) represents the inside of two straight lines parallel to the x-axis
  • formula (5-2) represents the inside of two straight lines extending diagonally in the graph
  • the compressive strain value xB and compressive stress value yB that simultaneously satisfy formula (b5-1) and formula (b5-2) are present in the region surrounded by these straight lines (region (b5)).
  • a layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formula (b5-1) and formula (b5-2) can occur can be said to be a layer in which at least one combination of compressive strain value xB and compressive stress value yB obtained by a compression test belongs to this region (b5). Furthermore, even if there is no combination of specific measured values in the compression test that falls within region (b5), if an approximation curve of compressive strain value xB and compressive stress value yB passes through region (b5), the layer can be considered to belong to region (b5).
  • a "layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formulas (b5-1) and (b5-2) can occur” can be said to be a layer in which the so-called “stress-strain curve (S-S curve)" obtained by the compression test passes through region (b5).
  • the left side of formula (b5-2), "0.129x B -9.575”, represents a line connecting the point where the compressive strain value is “75%” and the compressive stress value is "0.10 MPa” and the point where the compressive strain value is "85%” and the compressive stress value is "1.39 MPa”, and the slope of "0.129” and the intercept of "-9.575” are calculated from these points. Therefore, the compressive strain value is expressed in “%”, and the compressive stress value is expressed in "MPa".
  • the buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b6-1) and (b6-2) when the above-mentioned compression test is carried out.
  • Formula (b6-1) 0.20 ⁇ y B ⁇ 1.10
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b7-1) and (b7-2) when the above-mentioned compression test is carried out.
  • Formula (b7-1) 0.30 ⁇ y B ⁇ 0.90
  • Formula (b7-2) 0.12x B -8.70 ⁇ y B ⁇ 0.04x B -0.90
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the left side of formula (b7-2) "0.12x B -8.70” represents a straight line connecting the point where the compressive strain value is “75%” and the compressive stress value is "0.30 MPa” and the point where the compressive strain value is "80%” and the compressive stress value is "0.90 MPa”, and the slope "0.12" and the intercept "-8.70” are calculated from these points.
  • the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b8-1) and (b8-2) when the above-mentioned compression test is carried out.
  • Formula (b8-1) 0.40 ⁇ y B ⁇ 0.80
  • Formula (b8-2) 0.08x B -5.60 ⁇ y B ⁇ 0.032x B -0.88
  • the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
  • the stress-strain curve obtained by the compression test passes through the region surrounded by formula (b5-1) and formula (b5-2) (region (b5)), preferably the region surrounded by formula (b6-1) and formula (b6-2) (region (b6)), more preferably the region surrounded by formula (b7-1) and formula (b7-2) (region (b7)), and even more preferably the region surrounded by formula (b8-1) and formula (b8-2) (region (b8)).
  • the buffer layer tends to realize a heat insulating material with good heat insulating properties and cushioning properties (for example, good compression properties in a loading-unloading test under low pressure conditions, which will be described later).
  • the heat insulating layer is not particularly limited as long as it contains inorganic particles.
  • the heat insulating layer in the heat insulating material is preferably a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a1-1) and formula (a1-2) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min. That is, it is preferable that the stress-strain curve obtained by the compression test passes through the region surrounded by formula (a1-1) and formula (a1-2) (region (a1)).
  • the insulating layer is a layer in which the above-mentioned compression state can occur, better insulating properties can be ensured. The harder the insulating layer is, that is, the lower the compressive strain and the higher the compressive stress, the easier it tends to be to ensure good insulating properties. Therefore, by ensuring sufficient cushioning properties with the aforementioned buffer layer, it becomes possible to employ an insulating layer that is more specialized for ensuring insulating properties, resulting in an insulating material with suitable insulating properties and cushioning properties.
  • the left side of formula (a1-2), "0.12x A -2.45", represents a line connecting the point where the compressive strain value is “25%” and the compressive stress value is "0.50 MPa” and the point where the compressive strain value is "50%” and the compressive stress value is "3.45 MPa”. From these points, the slope of "0.12" and the intercept of "-2.45" are calculated.
  • the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a2-1) and (a2-2) when the above-mentioned compression test is carried out.
  • the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
  • the left side of formula (a2-2), "0.20x A -3.00", represents a line connecting the point where the compressive strain value is “20%” and the compressive stress value is "1.00 MPa” and the point where the compressive strain value is "30%” and the compressive stress value is “3.00 MPa”. From these points, the slope of "0.20” and the intercept of "-3.00" are calculated.
  • the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a3-1) and (a3-2) when the above-mentioned compression test is carried out.
  • Formula (a3-1) 1.50 ⁇ y A ⁇ 2.50
  • Formula (a3-2) 0.20xA -1.50 ⁇ yA
  • the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
  • the left side of formula (a3-2), "0.20x A -1.50”, represents a line connecting the point where the compressive strain value is “15%” and the compressive stress value is "1.50 MPa” and the point where the compressive strain value is "20%” and the compressive stress value is "2.50 MPa”. From these points, the slope of "0.20” and the intercept of "-1.50” are calculated.
  • the thermal insulation layer in the thermal insulation material is preferably a layer that can produce a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulas (a4-1) and (a4-2) when a compression test is performed on only the thermal insulation layer at a compression speed of 0.5 mm/min.
  • Formula (a4-1) 0.10 ⁇ y A ⁇ 1.39
  • Formula (a4-2) 0.043x A -0.545 ⁇ y A If the insulating layer is a layer in which the above-mentioned compression state can occur, better insulating properties can be ensured.
  • the left side of formula (a4-2), "0.043x A -0.545”, represents a line connecting the point where the compressive strain value is “15%” and the compressive stress value is "0.10 MPa” and the point where the compressive strain value is "45%” and the compressive stress value is "1.39 MPa”. From these points, the slope of "0.043” and the intercept of "-0.545” are calculated.
  • the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a5-1) and (a5-2) when the above-mentioned compression test is carried out.
  • Formula (a5-1) 0.20 ⁇ y A ⁇ 1.10
  • Formula (a5-2) 0.09x A ⁇ 1.15 ⁇ y A
  • the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
  • the left side of formula (a5-2), "0.09x A -1.15", represents a line connecting the point where the compressive strain value is “15%” and the compressive stress value is "0.20 MPa” and the point where the compressive strain value is “25%” and the compressive stress value is "1.10 MPa”. From these points, the slope of "0.09” and the intercept of "-1.15" are calculated.
  • the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a6-1) and (a6-2) when the above-mentioned compression test is carried out.
  • Formula (a6-1) 0.30 ⁇ y A ⁇ 0.90
  • Formula (a6-2) 0.12x A -0.90 ⁇ y A
  • the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
  • the left side of formula (a6-2), "0.12x A -0.90" represents a line connecting the point where the compressive strain value is “10%” and the compressive stress value is "0.30 MPa” and the point where the compressive strain value is “15%” and the compressive stress value is "0.90 MPa”. From these points, the slope of "0.12" and the intercept of "-0.90" are calculated.
  • An insulating layer in which the stress-strain curve obtained by the above compression test passes through the region enclosed by formulas (a1-1) and (a1-2) (region (a1)), preferably the region enclosed by formulas (a2-1) and (a2-2) (region (a2)), and more preferably the region enclosed by formulas (a3-1) and (a3-2) (region (a3)), tends to easily realize an insulating material with good insulating properties and cushioning properties (for example, good compression characteristics in a loading-unloading test under high pressure conditions described below) when combined with a buffer layer, in which the above stress-strain curve passes through region (b1) (preferably region (b2), more preferably region (b3), and even more preferably region (b4)).
  • region (b1) preferably region (b2), more preferably region (b3), and even more preferably region (b4)
  • the heat insulating layer is a layer containing inorganic particles.
  • a layer containing inorganic particles means that it contains at least inorganic particles as a constituent material and is formed in a layer shape.
  • the type of inorganic particles is not particularly limited, and examples thereof include silicon dioxide particles (silica), titanium oxide particles, zinc oxide particles, aluminum oxide particles, silicon carbide particles, ilmenite particles (ilmenite, FeTiO), zirconium silicate particles, iron (III) oxide particles, iron (II) (wustite (FeO) particles, magnetite particles (Fe 3 O 4 ), hematite particles (Fe 2 O 3 )), chromium dioxide particles, zirconium oxide particles, manganese dioxide particles, zirconia sol, titania sol, silica sol, alumina sol, bentonite particles, and kaolin particles.
  • inorganic particles include carbon-based particles such as graphite, carbon black, and carbon.
  • graphite those with a particle diameter of 18 ⁇ m or less are preferable.
  • the shape of graphite may be any of flake, scaly, spherical, isotropic (artificial), anisotropic (artificial), etc.
  • flake graphite examples include BF-3AK, FBF, BF-10AK (manufactured by Chuetsu Graphite Industries Co., Ltd.), GE-1, Z-5F, CNP7, and V-10F (manufactured by Ito Graphite Industries Co., Ltd.), examples of scaly graphite include HLP and SB-1 (manufactured by Chuetsu Graphite Industries Co., Ltd.), examples of spherical graphite include SG-BH8 (manufactured by Ito Graphite Industries Co., Ltd.), examples of isotropic graphite (artificial) include AGB-5 (manufactured by Ito Graphite Industries Co., Ltd.), and examples of anisotropic graphite (artificial) include AG-6T (manufactured by Ito Graphite Industries Co., Ltd.).
  • the heat insulating layer may contain one type of inorganic particles or may contain two or more types of inorganic particles.
  • the inorganic particles are preferably inorganic particles that can suppress thermal radiation, more specifically, have an absorption peak in the infrared region. The absorption peak in the infrared region can be measured by an infrared spectrophotometer.
  • the inorganic particles may also function as a binder that binds inorganic fibers together.
  • the content of inorganic particles in the heat insulating layer is not particularly limited, and is, for example, 50% to 99.5% by mass of the heat insulating layer, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.
  • the content of inorganic particles is within the above range, it becomes easier to ensure good heat insulating properties and mechanical strength.
  • the heat insulating layer preferably contains silicon dioxide (silica, SiO 2 ) as inorganic particles.
  • Silicon dioxide particles can be classified into crystalline silica, amorphous silica, etc. according to structural characteristics, and can be classified into natural silica, synthetic silica, etc. according to the method of acquisition.
  • Synthetic silica can be classified into dry silica, wet silica, silica aerogel, etc. according to the manufacturing method, and dry silica can be further classified into silica obtained by a combustion method, silica obtained by an arc method, etc., and wet silica can be classified into silica obtained by a gel method, silica obtained by a precipitation method, etc.
  • the type of silicon dioxide particles is not particularly limited, but dry silica and silica aerogel are preferred, and fumed silica is more preferred as a type of dry silica, and hydrophilic fumed silica is particularly preferred among fumed silica.
  • the hydrophilic fumed silica (Fumed Silica) refers to fumed silica that mainly has hydrophilic silanol groups (Si-OH) on the surface, and generally refers to fumed silica in which the silanol groups have not been substituted with hydrophobic groups by surface treatment or the like.
  • silicon dioxide particles generally exist as aggregates of primary particles, or aggregates further aggregate to form aggregated particles.
  • the silicon dioxide particles in the heat insulating layer disclosed herein may be dispersed in the form of primary particles, aggregates, aggregated particles, or a combination thereof.
  • the average primary particle diameter of the silicon dioxide particles is not particularly limited, and is, for example, 1 nm to 100 nm, preferably 2 nm or more, more preferably 4 nm or more, preferably 80 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, and particularly preferably 20 nm or less.
  • the average primary particle diameter is, for example, 1 nm to 40 nm, preferably 2 nm or more, more preferably 4 nm or more, preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 18 nm or less.
  • the average primary particle diameter is, for example, 1 nm to 20 nm, preferably 18 nm or less, and more preferably 10 nm or less.
  • the average primary particle diameter of the silicon dioxide particles is within the above range, good thermal insulation is easily ensured.
  • a method for determining the average primary particle diameter of the silicon dioxide particles a method of measuring using an electron microscope such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM) can be mentioned. Specifically, one method is to randomly select silicon dioxide particles seen under an electron microscope, measure their particle diameter, and calculate the average value. The particle diameter can be calculated by measuring the diameter if the particle is spherical, the midpoint between the short and long axes if the particle is elliptical, or the midpoint between the short and long sides if the particle is irregular.
  • the average particle size of secondary agglomerates of silicon dioxide particles is not particularly limited, and is, for example, 0.1 ⁇ m to 100 ⁇ m, preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, and preferably 90 ⁇ m or less, more preferably 80 ⁇ m or less.
  • the average particle size of secondary agglomerates of silicon dioxide particles can be determined by measuring them in the same manner as the primary particle size.
  • the BET specific surface area of the silicon dioxide particles is, for example, 90 m 2 /g or more and less than 380 m 2 /g, preferably 130 m 2 /g or more, more preferably 175 m 2 /g or more, even more preferably 200 m 2 /g or more, and preferably 350 m 2 /g or less, more preferably 320 m 2 /g or less, and even more preferably 200 m 2 /g or less. If the BET specific surface area of the silicon dioxide particles is within the above range, it is easy to ensure heat insulation even under high temperature and high humidity conditions.
  • the BET specific surface area can be measured by a multipoint nitrogen adsorption method (BET method) according to the measurement method of the International Organization for Standardization ISO 5794/1.
  • BET method multipoint nitrogen adsorption method
  • the nominal value of the BET specific surface area of "AEROSIL380" manufactured by Aerosil Corporation is 380 m 2 /g, and when an error is taken into consideration, the range is expressed as 350 m 2 /g to 410 m 2 /g. In this case, the nominal value of 380 m 2 /g is considered as the standard in this specification.
  • the apparent specific gravity of the silicon dioxide particles is not particularly limited, and is, for example, 30 g/L to 130 g/L, preferably 40 g/L or more, more preferably 50 g/L or more, and preferably 100 g/L or less, more preferably 80 g/L or less, and even more preferably 60 g/L or less.
  • silicon dioxide particles include hydrophilic fumed silica such as AEROSIL 50, 90, 130, 200, 300, 380 from the AEROSIL series (manufactured by Nippon Aerosil Co., Ltd.), QS-09, QS-10, QS-102, QS-20, QS-30, QS-40 from the Reolosil series (manufactured by Tokuyama Corporation), HDKV15, N20, T30, T40 from the HDK series (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.), hydrophobic fumed silica such as AEROSIL R972, R976S from the AEROSIL series (manufactured by Nippon Aerosil Co., Ltd.), HDK H15, H20, H30 from the HDK series (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.), and silica aerogel such as Airica (manufactured by Tokuyama Corporation).
  • the content of silicon dioxide particles in the insulating layer is not particularly limited, and is, for example, 50% by mass or more (typically 50% by mass to 99.5% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.
  • 50% by mass or more typically 50% by mass to 99.5% by mass
  • the content of silicon dioxide particles in the insulating layer is not particularly limited, and is, for example, 50% by mass or more (typically 50% by mass to 99.5% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.
  • the insulating layer may contain other components as long as it is a layer containing the inorganic particles described above. In some embodiments, it is preferable that the insulating layer contains inorganic fibers.
  • the type of inorganic fiber is not particularly limited, but examples include silica fiber, glass fiber, alumina fiber, silica-alumina fiber, silica-alumina-magnesia fiber, biosoluble inorganic fiber, glass fiber, zirconia fiber, alkaline earth silicate fiber, alkaline earth silicate (AES) fiber, glass wool, rock wool, and basalt fiber.
  • the insulating layer may contain one type of inorganic fiber, or two or more types of inorganic fibers.
  • the content of inorganic fibers in the insulating layer is not particularly limited, and is, for example, 0.5% by mass to 50% by mass, preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. If the fiber content is within the above range, it becomes easier to ensure good thermal resistance and to manufacture the insulating layer.
  • the average fiber length of the inorganic fibers contained in the insulating layer is not particularly limited, and is, for example, 0.05 mm to 50 mm, preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 2 mm or more, and preferably 35 mm or less, more preferably 30 mm or less, more preferably 25 mm or less, more preferably 13 mm or less, even more preferably 10 mm or less, and may be 8 mm or less, or 6 mm or less.
  • the average fiber length of the fibers is within the above range, it is easier to manufacture the insulating layer.
  • the average fiber diameter of the inorganic fibers contained in the thermal insulation layer is not particularly limited, and is, for example, 0.1 ⁇ m to 50 ⁇ m, preferably 1 ⁇ m or more, more preferably 5 ⁇ m or more, even more preferably 7 ⁇ m or more, and preferably 25 ⁇ m or less, more preferably 20 ⁇ m or less, even more preferably 15 ⁇ m or less.
  • 0.1 ⁇ m to 50 ⁇ m preferably 1 ⁇ m or more, more preferably 5 ⁇ m or more, even more preferably 7 ⁇ m or more, and preferably 25 ⁇ m or less, more preferably 20 ⁇ m or less, even more preferably 15 ⁇ m or less.
  • the heat insulating layer may contain organic fibers.
  • organic fibers include cellulose fibers, polyester, felt made of polypropylene, etc.
  • the use of organic fibers can be advantageous in terms of improving cushioning properties and durability against repeated pressure fatigue.
  • the content of organic fibers in the heat insulating layer can be appropriately set so as to obtain the desired usage effect, and may be, for example, more than 0 parts by mass, 1 part by mass or more, 4 parts by mass or more, 8 parts by mass or more, or 16 parts by mass or more, relative to 100 parts by mass of inorganic fibers.
  • the content of organic fibers in the heat insulating layer is suitably less than 100 parts by mass, advantageously less than 50 parts by mass, may be less than 20 parts by mass, may be less than 10 parts by mass, may be less than 5 parts by mass, or may be less than 1 part by mass, or may be an insulation layer that does not contain organic fibers.
  • the heat insulating layer may contain a binder (binding agent) as one of the other components in addition to the inorganic particles described above.
  • the heat insulating layer may contain one type of binder, or may contain two or more types of binders. When the heat insulating layer contains a binder, shape stability tends to be improved.
  • the type of binder is not particularly limited, but can be classified into organic binders and inorganic binders.
  • organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, water-soluble polymers, etc.
  • inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, calcium oxide, etc. If the binder is one of the above, shape stability is effectively improved.
  • the binder content is not particularly limited, and is, for example, 0.01% to 10% by mass of the insulating layer, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.
  • the binder content is within the above range, it becomes easier to achieve both thermal insulation and shape stability.
  • the heat insulating layer is a layer containing the aforementioned inorganic particles, and is preferably a molded body formed from a mixture containing inorganic particles and inorganic fibers.
  • a molded body formed from a mixture containing inorganic particles and inorganic fibers makes it easier to achieve both thermal insulation and mechanical strength. Details of the method of mixing the inorganic particles, inorganic fibers, etc. when the heat insulating layer is a molded body formed from a mixture containing inorganic particles and inorganic fibers will be described later.
  • the thickness of the insulating layer is not particularly limited, and is, for example, 0.5 mm to 10 mm, preferably 0.7 mm or more, more preferably 0.8 mm or more or 0.9 mm or more. In some embodiments, the thickness of the insulating layer is preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. When the thickness of the insulating layer is within the above range, good insulation properties can be easily ensured and the size of the insulating material can be suppressed.
  • the thickness of the insulating layer may be less than 2 mm, less than 1.5 mm, 1.3 mm or less, or 1 mm or less. By reducing the thickness of the insulating layer, the insulating material can be made thinner and lighter.
  • the thickness of the insulating layer can be the average value of the values measured at several points (for example, 10 points) on the cross section of the insulating layer with a thickness gauge (for example, Ozaki Manufacturing's digital thickness gauge JAN-257 (measuring probe ⁇ 20 mm)).
  • the density of the heat insulating layer is not particularly limited and is, for example, 0.2 to 0.5 g/ cm3 , preferably 0.3 g/ cm3 or more, more preferably 0.35 g/ cm3 or more, even more preferably 0.37 g/ cm3 or more, and preferably 0.45 g/ cm3 or less.
  • the thermal conductivity of the insulating layer at 80°C and 2 MPa pressure is preferably 0.010 W/K ⁇ m or more, and preferably 0.3 W/K ⁇ m or less, more preferably 0.1 W/K ⁇ m or less, more preferably 0.08 W/K ⁇ m or less, more preferably 0.06 W/K ⁇ m or less, more preferably 0.055 W/K ⁇ m or less, more preferably 0.045 W/K ⁇ m or less, and even more preferably 0.04 W/K ⁇ m or less.
  • the thermal conductivity of the insulating layer at 600°C and 2 MPa pressure is preferably 0.010 W/K ⁇ m or more, and preferably 0.3 W/K ⁇ m or less, more preferably 0.2 W/K ⁇ m or less, more preferably 0.1 W/K ⁇ m or less, more preferably 0.08 W/K ⁇ m or less, and even more preferably 0.075 W/K ⁇ m or less.
  • the thermal resistance at 80°C and 2 MPa pressure is preferably 0.020 (K ⁇ m 2 )/W or more, more preferably 0.025 (K ⁇ m 2 )/W or more, more preferably 0.03 (K ⁇ m 2 )/W or more, even more preferably 0.035 (K ⁇ m 2 )/W or more, and preferably 0.1 (K ⁇ m 2 )/W or less.
  • the thermal resistance of the insulating layer with an initial thickness of 2 mm at 600°C and 2 MPa pressure is preferably 0.010 (K ⁇ m 2 )/W or more, more preferably 0.015 (K ⁇ m 2 )/W or more, even more preferably 0.020 (K ⁇ m 2 )/W or more, and preferably 0.1 (K ⁇ m 2 )/W or less.
  • the thermal conductivity of the insulation layer can be measured using the method described in Japanese Industrial Standards JIS A 1412-2:1999 "Methods for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method (HFM method)."
  • the heat flow meter method is a secondary or comparative measurement method that measures heat transfer characteristics such as thermal conductivity and thermal resistance by comparing a flat thermal insulation material (insulation layer) as a test specimen with a standard plate. The detailed measurement procedure and conditions are explained below.
  • the insulation layer is cut to a specified size (e.g., 20 mm x 20 mm) to prepare the test specimen, and an alumina composite material ("RS-100", manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W/K ⁇ m) is prepared as the standard plate.
  • alumina composite material "RS-100", manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W/K ⁇ m) is prepared as the standard plate.
  • the first thermocouple, titanium plate, insulation layer, titanium plate, second thermocouple, standard plate, and third thermocouple are placed on the lower plate of the pneumatic press in this order from the top, and the test specimen, standard plate, thermocouple, etc. are tightly pressed between the upper and lower plates.
  • the upper and lower plates are then heated to the specified measurement temperature, and the test specimen, etc. are pressed by applying a load using the pneumatic press to reach the specified measurement pressure.
  • the measurement temperatures are as follows: the temperature of the upper plate on the first thermocouple side is 80°C, and the temperature of the lower plate on the third thermocouple side is 30°C.
  • the measurement temperatures under high temperature conditions are as follows: the temperature of the upper plate on the first thermocouple side is 600°C, and the temperature of the lower plate on the third thermocouple side is 40°C.
  • the measurement pressure may be 2 MPa (load: 800 N). Under the heating and pressurizing condition, the measurement is continued until the temperature detected by each thermocouple stabilizes, and the thermal conductivity k1 of the thermal insulation layer can be calculated from the temperature detected by each thermocouple after the temperature stabilizes, the thickness of the thermal insulation layer when pressed, the thermal conductivity of the standard plate, and the thickness of the standard plate when pressed, according to the following formula (I).
  • k1 k2 ⁇ (L1 ⁇ T1)/(L2 ⁇ T2) (I)
  • k1 is the thermal conductivity of the insulating layer [W/(m K)]
  • k2 is the thermal conductivity of the standard plate [W/(m K)]
  • L1 is the thickness of the insulating layer when pressed
  • L2 is the thickness of the standard plate
  • ⁇ T1 is the temperature difference between the temperatures of the second thermocouple and the third thermocouple
  • ⁇ T2 is the temperature difference between the temperatures of the first thermocouple and the second thermocouple.
  • the detected temperature is stabilized when the temperature change after about 10 minutes is within a specified range (for example, within ⁇ 0.1°C).
  • the thermal resistance of the heat insulating layer can be calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 according to the following formula (II).
  • R1 L1/k1 (II) (In the formula, R1 is the thermal resistance of the insulating layer [( m2 ⁇ K)/W], k1 is the thermal conductivity of the insulating layer [W/(m ⁇ K)], and L1 is the thickness of the insulating layer when pressed [m].)
  • the value of the compressive strain when the compressive stress value is 3.45 MPa may be, for example, 55% or less or 50% or less, and from the viewpoint of the durability of the insulation layer and the suppression of powder generation from the insulation layer (for example, powder generation due to falling off of inorganic particles), it is advantageous to have a value of 40% or less, and preferably a value of 35% or less or 30% or less, and may be 25% or less or 20% or less.
  • the 3.45 MPa compression strain of the insulation layer is more than 0%, and may be, for example, 7% or more, or may be 10% or more, 12% or more, 15% or more, or 20% or more.
  • An insulating layer having a 3.45 MPa compressive strain within any of the ranges described above, when combined with any of the buffer layers disclosed herein, is likely to produce an insulating material with good insulation and buffer properties (e.g., good compression characteristics in the loading-unloading test under high pressure conditions described below).
  • the 1.39 MPa compression strain of the thermal insulation layer constituting the thermal insulation material may be, for example, 45% or less or 40% or less, and from the viewpoints of durability and suppression of powder generation, etc., it is preferably 30% or less or 25% or less, advantageously 20% or less, and may be 18% or less, 15% or less, or 13% or less.
  • the 1.39 MPa compression strain of the above-mentioned thermal insulation layer is more than 0%, and may be, for example, 5% or more, 7% or more, 10% or more, 12% or more, or 15% or more.
  • thermal insulation material having good thermal insulation and buffer properties (for example, good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) is easily realized.
  • the 1.00 MPa compression strain of the insulating layer constituting the insulating material is, for example, suitably 40% or less, preferably 25% or less or 20% or less, advantageously 18% or less, and may be 15% or less, 12% or less, or 10% or less.
  • the 1.00 MPa compression strain of the insulating layer is greater than 0%, and may be, for example, 4% or more, 6% or more, 8% or more, 10% or more, or 12% or more.
  • An insulating layer having a 1.00 MPa compression strain in any of the above-mentioned ranges is likely to realize an insulating material having good insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described below) in combination with any of the buffer layers disclosed herein.
  • the insulating layer constituting the insulating material suitably has a strain at 0.34 MPa compression of 30% or less, preferably 20% or less, and more preferably 15% or less.
  • the strain at 0.34 MPa compression of the insulating layer is greater than 0%, and may be, for example, 3% or more, 5% or more, 7% or more, or 9% or more.
  • An insulating layer having a strain at 0.34 MPa compression in any of the above-mentioned ranges is likely to realize an insulating material with good insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described below) in combination with any of the buffer layers disclosed herein.
  • the number of insulating layers is typically 1 or more, and typically 10 or less, preferably 7 or less, and more preferably 5 or less.
  • the technology disclosed herein can be preferably implemented in an embodiment in which the number of insulating layers is 3 or less or 2 or less (typically 1).
  • the insulating layer may be bonded to adjacent layers with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the insulating layer is not bonded with an adhesive or pressure-sensitive adhesive.
  • an adhesive or pressure-sensitive adhesive i.e., by not using an adhesive or pressure-sensitive adhesive, the thermal conductivity can be reduced compared to when an adhesive or pressure-sensitive adhesive is used.
  • the shape of the insulating layer is not particularly limited, but examples of shapes when viewed in a plane include polygons such as quadrangles, circles, ellipses, etc. Examples of quadrangles include rectangles (including squares and rectangles).
  • the buffer layer is a layer made of a fiber-containing molded body (hereinafter sometimes abbreviated as "fiber-containing molded body”) or a foam-containing molded body (hereinafter sometimes abbreviated as “foam-containing molded body”).
  • a layer made of a fiber-containing molded body means a layer containing at least fiber as a constituent material
  • a layer made of a foam-containing molded body means a layer containing at least foam as a constituent material.
  • the buffer layer is a molded body (fiber molded body) containing fibers.
  • the aforementioned heat insulating layer is also preferably a molded body formed from a mixture containing inorganic particles and inorganic fibers, when the heat insulating layer is such a molded body, it can be distinguished from the fiber molded body in the buffer layer by whether or not it contains inorganic particles.
  • a layer containing inorganic particles can be determined as the heat insulating layer
  • a layer not containing inorganic particles but containing fibers can be determined as the buffer layer.
  • the fiber molded body in the buffer layer is preferably a molded body not containing inorganic particles but containing fibers.
  • the type of fiber in the fiber molding is not particularly limited, but can be classified into inorganic and organic fibers, as in the heat insulating layer. Specific examples include inorganic fibers such as glass wool, rock wool, and glass mat (glass needle mat), and organic fibers such as cellulose fiber, polyester, and felt made of polypropylene, etc., but inorganic fibers are preferred, and glass wool is particularly preferred. Glass wool is a hardened material containing fibers and a thermosetting resin (e.g., a phenol binder), and the fibers are bonded together with the thermosetting resin. It also has the effect of increasing compressive stress and exerting a buffer function.
  • the fiber molding may contain one type of fiber, or may contain two or more types of fibers.
  • the fiber assembly may be in the form of a nonwoven fabric, woven fabric, knitted fabric, etc., for example, a nonwoven fabric.
  • the fiber content in the fiber molding is not particularly limited, and is, for example, 50% by mass or more (typically 50% by mass to 99% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more (for example, 82% by mass or more), and preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less.
  • 50% by mass or more typically 50% by mass to 99% by mass
  • 97% by mass or less more preferably 95% by mass or less
  • even more preferably 93% by mass or less even more preferably 93% by mass or less.
  • the average fiber length of the fibers in the fiber molding is not particularly limited, and is, for example, 1 mm to 200 mm, preferably 5 mm or more, more preferably 10 mm or more, even more preferably 20 mm or more, and preferably 175 mm or less, more preferably 150 mm or less, even more preferably 125 mm or less. If the average fiber length of the fibers is within the above range, it becomes easier for the fibers to exhibit cushioning properties.
  • the average fiber diameter of the fibers in the fiber molding is not particularly limited, and is, for example, 3 ⁇ m to 13 ⁇ m, preferably 4 ⁇ m or more, more preferably 4.5 ⁇ m or more, even more preferably 5 ⁇ m or more, and preferably 10 ⁇ m or less, more preferably 9 ⁇ m or less, even more preferably 8 ⁇ m or less.
  • the fiber molding is more likely to achieve both cushioning properties and low thermal conductivity.
  • the fiber molding preferably contains a binder in addition to the fibers.
  • the type of binder in the fiber molding is not particularly limited, but can be classified into organic binders and inorganic binders.
  • organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, water-soluble polymers, etc.
  • inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, calcium oxide, etc. When the binder is one of the above, shape stability is improved.
  • the fiber molding may contain one type of binder or two or more types of binders.
  • the binder content in the fiber molding is not particularly limited, and may be, for example, 1% to 50% by mass of the fiber molding, preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and may be 10% by mass or more or 12% by mass or more, and may be 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and may be 18% by mass or less or 16% by mass or less.
  • the binder content is within the above range, low thermal conductivity and good cushioning properties are achieved.
  • the fiber molding is preferably a molding that does not contain hydrophilic fumed silica and is formed from a mixture that contains fibers and a binder.
  • Some fibers used in fiber moldings are sold with a thermosetting resin dispersed as a binder (attached to at least a portion of the fibers). Such fibers can be cut to the desired shape and then heated and compressed to form a fiber molding.
  • a foamed molded product is a molded product that contains a foam.
  • the material of the foam is usually a resin such as a thermoplastic resin or a thermosetting resin.
  • the foam can be molded by appropriately adopting a known molding method and its conditions.
  • the type of resin in the foam of the foam molded body is not particularly limited, and specific examples include polyolefin resins such as polyethylene and polypropylene, polyethylene terephthalate resin, polyvinyl chloride resin (PVC), styrene resins such as polystyrene, polyurethane resins such as polyurethane resin, resol-type phenolic resins such as phenolic resin (PF), melamine resins such as melamine resin (MF), epoxy resins such as epoxy resin (EP), and foams formed from resins such as natural rubber (NR), styrene butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), and polyurethane.
  • polyolefin resins such as polyethylene and polypropylene
  • PVC polyvinyl chloride resin
  • styrene resins such as polystyrene
  • polyurethane resins such as polyurethane resin
  • the cell structure of the foamed molded product may be either closed or open, and can be selected appropriately depending on the desired physical properties, etc.
  • the thickness of the buffer layer is, for example, 0.5 mm to 10 mm, preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less. If the thickness of the buffer layer is within the above range, it can adequately buffer the stress generated by the expansion of the battery.
  • the thickness of the buffer layer's cross section can be measured using a thickness gauge (digital thickness gauge JAN-257, probe ⁇ 20 mm, manufactured by Ozaki Manufacturing Co., Ltd.), and the average value of the numerical values obtained by performing this measurement at any number of locations (for example, 10 locations) can be used as the thickness of the buffer layer.
  • a thickness gauge digital thickness gauge JAN-257, probe ⁇ 20 mm, manufactured by Ozaki Manufacturing Co., Ltd.
  • the thermal conductivity of the buffer layer is not particularly limited.
  • the thermal conductivity of the buffer layer at 80°C and 2 MPa is preferably 0.030 W/K ⁇ m or more, more preferably 0.040 W/K ⁇ m or more, and even more preferably 0.050 W/K ⁇ m or more, and is preferably 0.2 W/K ⁇ m or less, more preferably 0.15 W/K ⁇ m or less, and even more preferably 0.1 W/K ⁇ m or less.
  • the thermal conductivity of the buffer layer at 600°C and 2 MPa is preferably 0.04 W/K ⁇ m or more, more preferably 0.05 W/K ⁇ m or more, and even more preferably 0.06 W/K ⁇ m or more, and is preferably 0.30 W/K ⁇ m or less, more preferably 0.25 W/K ⁇ m or less, and even more preferably 0.20 W/K ⁇ m or less.
  • the thermal conductivity of the buffer layer can be measured by the same method as the method for measuring the thermal conductivity of the insulating layer described above.
  • the thermal resistance of the buffer layer is not particularly limited.
  • the thermal resistance of the buffer layer under conditions of 80° C. and 2 MPa is preferably 0.020 (K ⁇ m 2 )/W or more, more preferably 0.025 (K ⁇ m 2 )/W or more, even more preferably 0.03 (K ⁇ m 2 )/W or more, and preferably 0.07 (K ⁇ m 2 )/W or less, more preferably 0.06 (K ⁇ m 2 )/W or less, even more preferably 0.05 (K ⁇ m 2 )/W or less.
  • the thermal resistance of the buffer layer at 600°C and 2 MPa is preferably 0.001 (K ⁇ m2 )/W or more, more preferably 0.003 (K ⁇ m2 )/W or more, even more preferably 0.005 (K ⁇ m2 )/W or more, and preferably 0.1 (K ⁇ m2 )/W or less, more preferably 0.05 (K ⁇ m2 )/W or less, even more preferably 0.01 (K ⁇ m2 )/W or less.
  • the thermal resistance of the buffer layer can be measured by the same method as the method for measuring the thermal conductivity of the heat insulating layer described above.
  • the value of the compressive strain when the compressive stress value is 3.45 MPa (hereinafter also referred to as "3.45 MPa compression strain"; other similar expressions are the same) may be, for example, 25% or more, advantageously 30% or more or 35% or more, preferably 40% or more, more preferably 45% or more, and may be 50% or more or 55% or more.
  • the 3.45 MPa compression strain of the buffer layer may be, for example, 90% or less, 85% or less (e.g., less than 85%), 80% or less, or 75% or less.
  • a buffer layer having a 3.45 MPa compression strain in any of the above-mentioned ranges is likely to realize a thermal insulation material with good thermal insulation and cushioning properties (for example, good compression characteristics in a loading-unloading test under high pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
  • the 1.39 MPa compression strain of the buffer layer constituting the insulating material may be, for example, 25% or more, advantageously 35% or more, preferably 45% or more, more preferably 50% or more or 55% or more, and may be 60% or more or 65% or more.
  • the 1.39 MPa compression strain of the buffer layer may be, for example, 90% or less, preferably 80% or less, and may be 75% or less.
  • a buffer layer having a 1.39 MPa compression strain in any of the above-mentioned ranges is likely to realize an insulating material with good insulation and cushioning properties (for example, good compression characteristics in a loading-unloading test under low pressure conditions described below) when combined with any of the insulating layers disclosed herein.
  • the strain at 1.00 MPa compression of the buffer layer constituting the thermal insulation material may be, for example, 5% or more, preferably 7% or more or 10% or more, and may be 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 50% or more, 55% or more, or 60% or more.
  • the strain at 1.00 MPa compression of the buffer layer may be, for example, 85% or less, preferably 80% or less, and may be 75% or less or 70% or less.
  • a buffer layer having a strain at 1.00 MPa compression in any of the above-mentioned ranges is likely to realize a thermal insulation material having good thermal insulation and cushioning properties (for example, good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
  • the 0.34 MPa compression strain of the buffer layer constituting the thermal insulation material may be, for example, 3% or more, 5% or more, preferably 10% or more, and may be 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more.
  • the 0.34 MPa compression strain of the buffer layer may be, for example, 75% or less, preferably 70% or less, and may be 65% or less, 60% or less, 50% or less, 40% or less, 35% or less, 25% or less, or 20% or less.
  • a buffer layer having a 0.34 MPa compression strain in any of the above-mentioned ranges is likely to realize a thermal insulation material having good thermal insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
  • the ratio of the strain at 0.34 MPa compression [%] of the buffer layer to the strain at 0.34 MPa compression [%] of the insulating layer is suitably 0.5 or greater, advantageously 0.75 or greater, and preferably 1.0 or greater (e.g., greater than 1.0).
  • a combination of an insulating layer and a buffer layer that satisfies the above-mentioned strain ratio at 0.34 MPa compression makes it easy to realize an insulating material that has good insulation and cushioning properties (e.g., good compression characteristics in one or both of the loading-unloading tests under high pressure conditions and the loading-unloading tests under low pressure conditions described below).
  • the above-mentioned strain ratio at 0.34 MPa compression is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more or 4.0 or more.
  • the ratio of the strain at 1.00 MPa compression [%] of the buffer layer to the strain at 1.00 MPa compression [%] of the insulating layer is suitably 0.5 or greater, advantageously 0.75 or greater, and preferably 1.0 or greater (e.g., greater than 1.0).
  • the above-mentioned strain ratio at 1.00 MPa compression is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more or 4.0 or more.
  • the ratio of the strain at 1.39 MPa compression [%] of the buffer layer to the strain at 1.39 MPa compression [%] of the thermal insulation layer is suitably 0.5 or more, advantageously 0.75 or more, and preferably 1.0 or more (e.g., more than 1.0).
  • a combination of a thermal insulation layer and a buffer layer that satisfies the above 1.39 MPa compression strain ratio makes it easy to realize a thermal insulation material with good thermal insulation and cushioning properties (e.g., good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions, which will be described later).
  • the above 1.39 MPa compression strain ratio is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more.
  • the number of buffer layers is usually 10 or less, preferably 5 or less, and more preferably 3 or less, and may be 2 or 1.
  • the buffer layer may be bonded to the adjacent layers with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the buffer layer is not bonded with an adhesive or pressure-sensitive adhesive.
  • an adhesive or pressure-sensitive adhesive i.e., by not using an adhesive or pressure-sensitive adhesive, the increase in thermal conductivity can be suppressed compared to when an adhesive or pressure-sensitive adhesive is used.
  • the shape of the buffer layer is not particularly limited, but examples of shapes when viewed in a plane include polygons such as quadrangles, circles, and ellipses. Examples of quadrangles include rectangles (including squares and rectangles).
  • the heat insulating material disclosed in this specification preferably includes a coating layer.
  • the coating layer is a layer that plays a role in suppressing the falling off of inorganic particles and the like of the heat insulating layer and protecting the heat insulating layer.
  • a coating layer formed using a resin film can be preferably adopted.
  • the type of resin for the coating layer is not particularly limited, but specific examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide (PI), flame-retardant polycarbonate (PC), breathable porous polyethylene (PE), flame-retardant polyethylene (PE), biaxially oriented nylon film (Ny), etc.
  • Breathable porous PE preferably has a molecular weight of 1 to 7 million.
  • the thickness of the coating layer is not particularly limited, and is, for example, 0.001 mm to 0.2 mm, preferably 0.005 mm or more, more preferably 0.007 mm or more, even more preferably 0.010 mm or more, and preferably 0.15 mm or less, more preferably 0.10 mm or less, even more preferably 0.050 mm or less.
  • the thickness of the coating layer can be measured in the same manner as the thickness of the insulating layer.
  • the number of coating layers is usually 1 or more, preferably 2 or more, and usually 5 or less, preferably 4 or less, and more preferably 3 or less.
  • the 2 or more coating layers may be 2 or more resin films, or a single resin film may be folded back to form 2 coating layers. When folded back in this way, the number of coating layers is considered to be 2.
  • the two or more coating layers may sandwich and enclose the insulating layer from the thickness direction, and the gaps between the coating layers (the space partitioned by the two or more coating layers) may be sealed.
  • the method for sealing the gaps between the coating layers is not particularly limited, but examples include providing a seal portion on the outer edge of the coating layer and bonding the seal portions between the coating layers.
  • the method for bonding the seal portions is also not particularly limited, and examples include welding using heat welding, ultrasonic welding, etc., and adhesion using adhesives, pressure sensitive adhesives, etc. In addition, welding may be performed by directly welding the resin of the coating layer, or by providing a separate resin layer for welding and welding it.
  • the covering layer may be bonded to the adjacent insulating layer with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the covering layer is not bonded with an adhesive or pressure-sensitive adhesive.
  • the insulation material includes two or more coating layers and the gaps between the two or more coating layers are sealed, it is preferable that the coating layers have an air vent that connects the gaps with the outside space.
  • the coating layers By having an air vent, shrink packaging, packaging using deep-drawn molded film, etc. can be used as a packaging method.
  • the number of ventilation holes in the coating layer is usually 1 or more, preferably 2 or more, and usually 50 or less, preferably 25 or less, and more preferably 10 or less.
  • the total opening area of the ventilation holes in the coating layer is usually 0.000079 cm 2 to 10 cm 2 , preferably 0.0001 cm 2 or more, more preferably 0.005 cm 2 or more, even more preferably 0.01 cm 2 or more, and preferably 5 cm 2 or less, more preferably 4 cm 2 or less, and even more preferably 3 cm 2 or less.
  • the total opening area of the ventilation holes in the coating layer is within the above range, it is easy to suppress powder outflow from the heat insulating layer.
  • the ventilation hole of the covering layer may be covered with a ventilation film.
  • the ventilation film usually has an air permeability of 4 cm 3 /(cm 2 ⁇ s) to 500 cm 3 /(cm 2 ⁇ s), preferably 7 cm 3 /(cm 2 ⁇ s) or more, more preferably 10 cm 3 /(cm 2 ⁇ s) or more, even more preferably 21 cm 3 /(cm 2 ⁇ s) or more, and preferably 250 cm 3 /(cm 2 ⁇ s) or less, more preferably 200 cm 3 /(cm 2 ⁇ s) or less, even more preferably 100 cm 3 /(cm 2 ⁇ s) or less.
  • the thermal conductivity of the insulating material at 80°C and 2 MPa is preferably 0.02 W/K ⁇ m or more, more preferably 0.03 W/K ⁇ m or more, even more preferably 0.04 W/K ⁇ m or more, and preferably 0.2 W/K ⁇ m or less, more preferably 0.15 W/K ⁇ m or less, even more preferably 0.10 W/K ⁇ m or less.
  • the thermal conductivity of the insulating material is measured by the same method as that for the thermal conductivity of the insulating layer.
  • the thermal resistance of the insulating material when adjusted to have an unpressurized thickness of 2 mm under conditions of 80°C and 2 MPa is not particularly limited, and is preferably 0.01 (K ⁇ m2 )/W or more, more preferably 0.02 (K ⁇ m2 )/W or more, even more preferably 0.03 (K ⁇ m2 )/W or more, and preferably 0.10 (K ⁇ m2 )/W or less, more preferably 0.09 (K ⁇ m2 )/W or less, even more preferably 0.08 (K ⁇ m2 )/W or less.
  • the thermal resistance of the insulating material is measured by the same method as that of the thermal resistance of the insulating layer.
  • the value (strain difference (Xhp)) obtained by subtracting the compressive strain at a pressure of 0.34 MPa during the compression process from the compressive strain at a pressure of 3.45 MPa is 15% or more (more preferably 20% or more, and even more preferably 25% or more), and that the value (strain difference (Xhr)) obtained by subtracting the compressive strain in a compressed state that results in the same displacement as the compressive stress of 0.34 MPa during the compression process during the compression-release process from the compressive strain at a pressure of 3.45 MPa is 5% or more.
  • the strain difference (Xhp) is 30% or more, and that the strain difference (Xhr) is 6% or more.
  • Insulating materials that exhibit the above-mentioned compression characteristics during the compression and compression-release processes of the loading-unloading test 1 are preferably used as insulating materials placed between cells in battery modules, for example, and can vary in thickness accordingly in response to repeated expansion and contraction of the cells, and can also exhibit cushioning properties that can generate appropriate stress.
  • the compressive strain at a pressure of 0.34 MPa in the compression process of the above-described load-unload test 1 is suitably 40% or less, advantageously 35% or less, preferably 30% or less (e.g., less than 30%), and may be 25% or less, 20% or less, or 15% or less.
  • the compressive strain at the above-described pressure of 0.34 MPa is typically more than 0%, and may be 3% or more, 5% or more, or 10% or more.
  • the compressive strain at a pressure of 3.45 MPa in the compression process of the above-described load-unload test 1 is suitably 20% or more, preferably 25% or more, more preferably 30% or more (e.g., more than 30%), may be 35% or more, or may be 40% or more.
  • the compressive strain at a pressure of 3.45 MPa may be, for example, 70% or less, or 65% or less, or 60% or less (for example, less than 60%).
  • the value obtained by subtracting the compressive strain at a pressure of 0.03 MPa during the compression process from the compressive strain at a pressure of 1.39 MPa is 15% or more (more preferably 20% or more or 25% or more, and even more preferably 30% or more), and the value obtained by subtracting the compressive strain in a compressed state that results in the same displacement as the compressive stress of 0.03 MPa during the compression process during the compression-release process from the compressive strain at a pressure of 1.39 MPa (strain difference (Xlr)) is 5% or more (more preferably 6% or more, and even more preferably 8% or more or 10% or more).
  • the strain difference (Xlp) is 30% or more, and the strain difference (Xlr) is 6% or more (even more preferably 8% or more, for example 10% or more).
  • Insulating materials that exhibit the above-mentioned compression characteristics during the compression and compression-release processes of the loading-unloading test 2 are preferably used as insulating materials placed between cells in battery modules, for example, and can vary in thickness accordingly in response to repeated expansion and contraction of the cells, and can also exhibit cushioning properties that can generate appropriate stress.
  • the compressive strain at a pressure of 0.03 MPa during the compression process of the above-described load-unload test 2 is suitably 40% or less, advantageously 35% or less, preferably 30% or less (e.g., less than 30%), and may be 25% or less, 20% or less, or 15% or less.
  • the compressive strain at the above-described pressure of 0.03 MPa is typically more than 0%, and may be 3% or more, 5% or more, or 10% or more.
  • the compressive strain at a pressure of 1.39 MPa during the compression process of the above-described load-unload test 2 is suitably 20% or more, preferably 30% or more (e.g., more than 30%), and may be 40% or more, 50% or more, or 55% or more.
  • the compressive strain at the pressure of 1.39 MPa may be, for example, 90% or less, 85% or less, 80% or less, 70% or less, or 60% or less (for example, less than 60%).
  • the uses of the insulating material disclosed herein are not particularly limited, and the material can be used appropriately in known applications for which insulating materials are used.
  • the insulating material according to some embodiments is preferably used as an insulating material disposed between cells of a battery module, and more specifically, is particularly preferably used as an insulating material disposed between cells of a lithium-ion battery module.
  • FIG. 2 is a perspective view showing a schematic example of a battery module in which a heat insulating material, which is an embodiment of the present invention, is disposed between cells
  • FIG. 3 is a cross-sectional view taken along line II-II thereof.
  • a battery module 50 comprises a plurality of battery cells (here rectangular cells) 51 arranged in the thickness direction, with heat insulating material 52 disposed between each battery cell 51.
  • the plurality of battery cells 51 thus arranged with heat insulating material 52 sandwiched between them are typically restrained with a pressing force (compressive force) applied in the thickness direction via restraining plates 52a, 52a arranged at both ends, and are housed in a battery case 53 for use.
  • the heat insulating material 52 has a structure in which a heat insulating layer 521 and a buffer layer 522 are laminated, and these are sandwiched and wrapped in two resin films (two coating layers) 523A, 523B from the thickness direction.
  • the resin films 523A, 523B are sealed by adhesion (for example, heat welding) at the seal parts provided along their outer edges, and are integrated to form the coating material 523.
  • the heat insulating material 52 having such a structure is sandwiched between two adjacent battery cells 51, 51, thereby exerting the effect of insulating the opposing surfaces 51a, 51a of the two battery cells 51, 51. Note that FIG.
  • FIG. 3 shows a structure in which two buffer layers 522A, 522B are laminated in the coating material 523, but the number of buffer layers may be one or two or more, and two or more buffer layers may be arranged separately on both sides of the heat insulating layer.
  • FIG. 3 shows a structure having only one heat insulating layer 521, but the number of heat insulating layers may be two or more.
  • the buffer layer may be disposed on the outside of the covering material, or multiple buffer layers may be disposed separately on the outside and inside of the covering material.
  • the covering material 523 may be provided with an air vent.
  • FIG. 4 is a perspective view showing a typical heat insulating material according to one embodiment
  • FIG. 5 is a cross-sectional view taken along line IV-IV in FIG. 4.
  • the heat insulating material 1 has a structure in which a heat insulating layer 10 consisting of two heat insulating layers 10A and 10B is laminated on one surface 20a of a buffer layer 20, and the heat insulating layer 10 is sandwiched and wrapped in two resin films (two coating layers) 31A and 31B in the thickness direction.
  • the resin films 31A and 31B are sealed by adhesion (for example, heat welding) at a seal portion 32 provided along their outer edges, and integrally form a coating material 30.
  • the resin film 31A is formed into a convex shape that generally covers the end face of the laminate of the heat insulating layer 10 and the buffer layer 20, and a vent (through hole) 33 is formed in the portion covering this end face.
  • An air permeable film 34 is arranged at the opening of the air permeable film 33 to the outside to prevent powder from flowing out from the heat insulating layer.
  • the Z direction (thickness direction of the insulating material 1) shown in Figure 5 is the arrangement direction of the cells
  • the Y direction is the electrode extraction direction of the cells, that is, the opening direction of the air vent in the insulating material 1 (X direction) and the electrode extraction direction of the cells do not coincide.
  • FIG. 6 is a cross-sectional view showing a schematic of an insulating material according to another embodiment.
  • two insulating layers 10A and 10B constituting the insulating layer 10 are laminated on one side 20a and the other side 20b of the buffer layer 20.
  • the insulating material 1 having such a configuration has a high structural symmetry in the thickness direction and is easy to suppress the temperature difference between the two sides, which may be advantageous from the viewpoint of preventing deformation (e.g., warping) of the insulating material.
  • the buffer layer 20 may have a laminated structure consisting of two layers of the buffer layers 20A and 20B, or a laminated structure of three or more layers.
  • the inner surface 10a of the insulating layer 10A and the buffer material 20 may or may not be bonded. The same applies to the bonding between the inner surface of the insulating layer 10B and the buffer material 20.
  • FIG. 8 is a cross-sectional view showing a schematic of an insulating material according to another embodiment.
  • the insulating layer 10 is enclosed in the covering material 30, while the buffer material 20 is disposed outside the covering material 30. More specifically, one surface 20a of the buffer material 20 is fixed to one surface of the covering material 30 via an adhesive layer 40 made of an adhesive or pressure-sensitive adhesive.
  • the insulating material disclosed herein can also be implemented in such an embodiment.
  • the target cells are not limited to rectangular cells, but may be, for example, laminated cells or cylindrical cells.
  • the shape of the insulation material can be appropriately adopted depending on the type of cell.
  • Devices that the batteries will be used on include electric vehicles such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs), portable electronic devices such as mobile terminals, mobile phones, and notebook computers, and wearable devices.
  • electric vehicles such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs)
  • portable electronic devices such as mobile terminals, mobile phones, and notebook computers, and wearable devices.
  • the method for producing the insulating material is not particularly limited, and the insulating material can be produced by appropriately adopting known processes. For example, a production method including the following steps can be mentioned.
  • - Heat insulating layer preparation step a step of preparing a heat insulating layer containing inorganic particles.
  • Buffer layer preparation step a step of preparing a buffer layer made of a fiber molded body containing fibers or a foamed molded body containing a foam.
  • - Lamination step a step of laminating a group of constituent layers including the heat insulating layer prepared in the heat insulating layer preparation step and the buffer layer prepared in the buffer layer preparation step.
  • the heat insulating layer preparation process, the buffer layer preparation process, and the lamination process may be processes that are performed simultaneously with other processes in a chronological order, or may be processes that are performed in sequence, as long as they do not refer to previous processes.
  • the buffer layer preparation step may include selecting a buffer layer that, when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min, passes through the above-mentioned region (b1) (preferably region (b2), more preferably region (b3), and even more preferably region (b4)) or passes through the above-mentioned region (b5) (preferably region (b6), more preferably region (b7), and even more preferably region (b8)).
  • a method for producing an insulating material includes: selecting a buffer layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min; and laminating an insulating layer containing inorganic particles and the buffer layer.
  • the heat insulating layer preparation step may include selecting a heat insulating layer that provides a stress-strain curve that passes through the above-mentioned region (a1) (preferably region (a2), more preferably region (a3)) or passes through the above-mentioned region (a4) (preferably region (a5), more preferably region (a6)) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min.
  • a method for manufacturing a heat insulating material includes: selecting a buffer layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min; selecting a heat insulating layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min; and laminating the heat insulating layer and the buffer layer. Also provided is a method for designing a heat insulating layer, which includes selecting the buffer layer and selecting the heat insulating layer.
  • the buffer layer preparation step may include selecting a buffer layer in which at least one of the 0.34 MPa compressive strain, 1.00 MPa compressive strain, 1.39 MPa compressive strain, and 3.45 MPa compressive strain is within any of the ranges disclosed in this specification.
  • a buffer layer in which at least the 0.34 MPa compressive strain and the 3.45 MPa compressive strain are within any of the ranges disclosed in this specification it is preferable to select a buffer layer in which at least the 0.34 MPa compressive strain and the 3.45 MPa compressive strain are within any of the ranges disclosed in this specification.
  • a buffer layer in which at least the 0.34 MPa compressive strain and the 1.39 MPa compressive strain are within any of the ranges disclosed in this specification.
  • the insulating layer preparation step may include selecting an insulating layer in which at least one of the 0.34 MPa compressive strain, 1.00 MPa compressive strain, 1.39 MPa compressive strain, and 3.45 MPa compressive strain is within any of the ranges disclosed herein.
  • the insulating layer preparation step may include selecting an insulating layer in which at least one of the 0.34 MPa compressive strain, 1.00 MPa compressive strain, 1.39 MPa compressive strain, and 3.45 MPa compressive strain is within any of the ranges disclosed herein.
  • an insulating material that exhibits good compressive properties in a loading-unloading test under low pressure conditions (i.e., loading-unloading test 2) described below, it is preferable to select an insulating layer in which the values of at least the 0.34 MPa compressive strain and the 1.39 MPa compressive strain are within any of the ranges disclosed herein. In some embodiments, it is more preferable to manufacture or design the insulation material taking into consideration the above-mentioned 0.34 MPa compression strain ratio (buffer layer/insulation layer) and 1.39 MPa compression strain ratio (buffer layer/insulation layer).
  • the method of preparing the heat insulating layer in the heat insulating layer preparation step is not particularly limited, and an existing heat insulating material may be obtained as the heat insulating layer, or the heat insulating layer may be prepared in the above preparation step.
  • the heat insulating layer is a layer formed by molding a mixture containing inorganic particles and inorganic fibers, it can be mixed by adopting a known mixing method such as a wet method or a dry method.
  • a preparation method using a wet method for example, a preparation method including the following steps can be mentioned.
  • Mixing process A process of mixing inorganic particles and inorganic fibers in a solvent to obtain a mixed liquid.
  • Coating process A process of applying the mixed liquid obtained in the mixing process to obtain a coating film.
  • Coating film forming process A process of forming the coating film obtained in the coating process to obtain a heat insulating layer.
  • the mixing process is a process in which inorganic particles and inorganic fibers are mixed in a solvent to obtain a mixed liquid.
  • This is a so-called wet method, and specifically, it is a process in which inorganic particles and inorganic fibers are mixed in a solvent to prepare a mixed liquid (slurry state).
  • a disper, a labo plasto mill, a trimix, a planetary mixer, a kneader, etc. can be used for mixing in the mixing process.
  • the type of solvent is not particularly limited, and examples include protic solvents such as alcohols, amides, and water, and aprotic solvents such as esters, ketones, nitriles, and ethers.
  • the surface tension of the solvent is not particularly limited, and is, for example, 20 mN/m to 73 mN/m, preferably 21 mN/m or more, preferably 50 mN/m or less, more preferably 40 mN/m or less, and even more preferably 30 mN/m or less. If the surface tension of the solvent is within the above range, the thermal insulation and mechanical strength will be good.
  • the surface tension of the solvent can be measured by the ring method, for example.
  • the mixing temperature is not particularly limited, and is, for example, 20°C or higher and the boiling point of the solvent or lower, preferably 22°C or higher, and preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower. If the mixing temperature is within the above range, the solvent (e.g., organic solvent) is less likely to volatilize, and the blending ratio is less likely to change.
  • the solvent e.g., organic solvent
  • the mixing time is not particularly limited, and is, for example, 1 minute to 5 hours, preferably 5 minutes or more, preferably 4 hours or less, more preferably 2 hours or less, and even more preferably 1 hour or less. If the mixing time is within the above range, the insulating material can be produced efficiently.
  • the consistency (constancy) of the mixed liquid is not particularly limited, and is, for example, 50 to 200, preferably 55 or more, more preferably 60 or more, even more preferably 65 or more, and preferably 180 or less, more preferably 160 or less, and even more preferably 140 or less. If the consistency of the mixed liquid is within the above range, fiber breakage can be reduced when the fibers are uniformly dispersed.
  • the method for measuring the consistency of the mixed liquid is as described in the Japanese Industrial Standard JIS K 2220:2013 "Grease - Part 7: Consistency test method", and in particular, the consistency can be measured as "immiscible consistency".
  • Measuring instruments that can measure consistency are commercially available, and a specific example is the PENETRO METER manufactured by Nikka Engineering.
  • the measurement procedure involves preparing a container large enough that the conical weight will not come into contact with the container when it is lowered, filling it with the mixed liquid, and placing it on the measuring instrument to which the weight is attached. Next, the position of the weight is adjusted so that it is in contact with the mixed liquid, and this position is designated as the zero point.
  • the conical weight should be a standard cone as specified in the Japanese Industrial Standards, with a total weight of 102.5g ⁇ 0.05g and a weight holder with a weight of 47.5 ⁇ 0.05g.
  • the coating method and conditions in the coating process are not particularly limited, and any known method can be used as appropriate.
  • coating can be done using a comma coater, spin coater, die coater, dispenser, etc.
  • the molding method and molding conditions in the coating film molding step are not particularly limited, and known methods can be appropriately adopted.
  • compression molding using a heat press or a vacuum press, and drying using a floating oven, an IR oven, or the like can be mentioned.
  • the drying temperature is preferably, for example, 60°C to 150°C.
  • the drying time is preferably, for example, 4 minutes to 20 minutes.
  • the above molding method and molding conditions can be selected so as to obtain a heat insulating layer with a desired density (for example, a density of 0.2 to 0.5 g/ cm3 ).
  • the method for preparing the buffer layer in the buffer layer preparation step is not particularly limited, and an existing heat insulating material or the like may be obtained as the buffer layer, or the buffer layer may be prepared in the above preparation step.
  • the buffer layer is a fiber molded body obtained by molding a mixture containing fibers and a binder
  • a preparation method including the following steps may be mentioned.
  • Precursor preparation step A step of preparing a precursor in which a binder is dispersed in fibers.
  • Precursor molding step A step of molding the precursor prepared in the precursor preparation step to obtain a buffer layer.
  • thermosetting resin dispersed in the fibers as a binder
  • the method for forming the precursor in the precursor forming process is not particularly limited, but examples include a method in which the precursor is heated and compressed using a heat press.
  • the method of laminating the constituent layers in the lamination process is not particularly limited, and the constituent layers may simply be stacked, or may be compressed using a known compression molding method and appropriate conditions, or adjacent layers may be bonded together with an adhesive or pressure sensitive adhesive. In addition, when two or more coating layers are used and the gaps between the coating layers are sealed, bonding the coating layers together is also included in the lamination process.
  • a heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foamed molded body containing a foam
  • the thermal insulation material is a layer in which, when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min, a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) can be generated.
  • a heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam,
  • the thermal insulation material is a layer in which a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) can be generated when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min.
  • the silicon dioxide particles are hydrophilic fumed silica.
  • the heat insulating layer is a molded body obtained by molding a mixture containing inorganic particles and inorganic fibers.
  • heat insulating material heat insulating layer A> 21 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 380", manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter: about 7 nm, BET specific surface area: 380 m 2 /g) and 4 parts by mass of inorganic glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd., average fiber diameter: 13 ⁇ m, average fiber length: 25 mm) were mixed in a plastic bag so as to be uniformly dispersed, with the fibers being loosened by hand in advance.
  • AEROSIL registered trademark
  • CS 25K-871 manufactured by Nitto Boseki Co., Ltd., average fiber diameter: 13 ⁇ m, average fiber length: 25 mm
  • thermal insulation layer A which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber.
  • the thickness of the obtained thermal insulation material (thermal insulation layer A) was 2 mm, and the density was 0.23 g/cm 3 .
  • heat insulating layer B ⁇ Production of heat insulating material (heat insulating layer B)>
  • a mixed solvent surface tension: 33 mN/m
  • acetic acid surface tension: 27 mN/m
  • protic solvent surface tension: 73 mN/m
  • 21 parts by mass of hydrophilic fumed silica particles (“AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.)
  • 4 parts by mass of glass fiber (“CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency measured by the method described below was 70 to 140.
  • AEROSIL hydrophilic fumed silica particles
  • CS 25K-871 glass fiber
  • the resulting mixed liquid was applied to a substrate so as to have a thickness of 4 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 2 mm and a density of 0.1 to 0.3 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer B) which is a molded body formed by molding a mixture containing hydrophilic fumed silica and glass fiber. The resulting heat insulating material (heat insulating layer B) had a thickness of 2 mm and a density of 0.33 g/cm 3 .
  • heat insulating layer C ⁇ Production of heat insulating material (heat insulating layer C)>
  • a mixed solvent surface tension: 33 mN/m
  • 21 parts by mass of hydrophilic fumed silica particles (“AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.)
  • 4 parts by mass of glass fiber (“CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency was 70 to 140.
  • AEROSIL hydrophilic fumed silica particles
  • CS 25K-871 manufactured by Nitto Boseki Co., Ltd.
  • the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 2 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer C) which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber.
  • the thickness of the obtained heat insulating material (heat insulating layer C) was 2 mm and the density was 0.37 g/cm 3 .
  • heat insulating layer D ⁇ Production of heat insulating material (heat insulating layer D)>
  • IPA isopropyl alcohol
  • IPA surface tension: 21 mN/m
  • water 100 parts by mass of hydrophilic fumed silica particles
  • CS 6J-888 20 parts by mass of glass fiber
  • CS 6J-888 manufactured by Nitto Boseki Co., Ltd., average fiber diameter: 11 ⁇ m, average fiber length: 6 mm
  • Kao Corporation's Kotamin 24P active ingredient: dodecyltrimethylammonium chloride (C 12 H 25 N + (CH 3 ) 3 Cl), active ingredient content: 27% by mass
  • non-polymeric dispersant 0.5 parts by mass as active ingredient (ammonium salt)
  • the resulting mixed solution was applied to a substrate to a thickness of 4 mm to form a coating film. Furthermore, the coating film was compression molded in a hot press into a sheet having a thickness of 2 mm and a density of 0.3 to 0.5 g/ cm3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer D) which is a molded product of a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant.
  • the obtained heat insulating material (heat insulating layer D) had a thickness of 2 mm and a density of 0.37 g/ cm3 .
  • heat insulating layer E ⁇ Production of heat insulating material (heat insulating layer E)> A sheet having a thickness of 2.1 mm and a density of 0.37 g/ cm3 was produced by the same manufacturing method as for the insulating layer D, and then the sheet was loaded at a compression speed of 0.5 mm/sec until a pressure of 2.1 MPa was reached, and then unloaded until the pressure reached 0 MPa. This additional pressurizing process was repeated 10 times to produce an insulating material (insulating layer E) that was a molded body made by molding a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained insulating material (insulating layer E) had a thickness of 2 mm and a density of 0.40 g/ cm3 .
  • heat insulating layer F ⁇ Manufacture of heat insulating material (heat insulating layer F)>
  • a mixed solvent surface tension: 33 mN/m
  • 21 parts by mass of hydrophilic fumed silica particles (“AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.)
  • 4 parts by mass of glass fiber (“CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency was 70 to 140.
  • AEROSIL hydrophilic fumed silica particles
  • CS 25K-871 manufactured by Nitto Boseki Co., Ltd.
  • the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 1 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer F) which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber.
  • the obtained heat insulating material (heat insulating layer F) had a thickness of 1 mm and a density of 0.37 g/cm 3 .
  • heat insulating layer G A sheet having a thickness of 1.1 mm and a density of 0.37 g/ cm3 was produced by the same manufacturing method as for the insulating layer F, and then the sheet was loaded at a compression speed of 0.5 mm/sec until a pressure of 1.39 MPa was reached, and then unloaded until the pressure reached 0 MPa. This additional pressurizing process was repeated 10 times to produce an insulating material (insulating layer G) that was a molded body made from a mixture containing hydrophilic fumed silica and glass fiber. The obtained insulating material (insulating layer G) had a thickness of 1 mm and a density of 0.40 g/ cm3 .
  • heat insulating layer H ⁇ Manufacture of heat insulating material (heat insulating layer H)> The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to obtain a thickness of 3.6 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to obtain a sheet-like film having a thickness of 1.8 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100° C.
  • heat insulating layer H that is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant.
  • the obtained heat insulating material (heat insulating layer H) had a thickness of 1.8 mm and a density of 0.37 g/cm 3 .
  • heat insulating layer I ⁇ Production of heat insulating material (heat insulating layer I)> The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to a thickness of 1.6 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 0.8 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer I) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer I) had a thickness of 0.8 mm and a density of 0.37 g/cm 3 .
  • heat insulating layer J ⁇ Manufacture of heat insulating material (heat insulating layer J)> The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to a thickness of 2.4 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 1.2 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer J) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer J) had a thickness of 1.2 mm and a density of 0.37 g/cm 3 .
  • heat insulating material heat insulating layer K> 10 parts by mass of graphite ("AGB-5", manufactured by Ito Graphite Industries, average particle size 5 ⁇ m) was added to the formulation of the insulating material D and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to a substrate to a thickness of 2.0 mm to form a coating film.
  • AGB-5 manufactured by Ito Graphite Industries, average particle size 5 ⁇ m
  • the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 1.0 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce an insulating material (insulating layer K) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, graphite, and a non-polymeric dispersant.
  • the obtained insulating material (insulating layer K) had a thickness of 1.0 mm and a density of 0.37 g/cm 3 .
  • the consistency of each mixed liquid was measured as "immiscible consistency" in accordance with the contents described in the Japanese Industrial Standard JIS K 2220:2013 "Grease - Part 7: Consistency test method". Specifically, a pot large enough that a conical weight would not come into contact with the mixture when lowered was prepared, filled with the mixed liquid, and placed in a Nikka Engineering PENETRO METER with a weight attached. The position of the weight was then adjusted so that it came into contact with the mixed liquid, and this position was designated as the zero point.
  • the weight was then lowered for 5 seconds ( ⁇ 0.1 seconds) under room temperature (25°C) conditions, and the consistency was calculated as the depth (mm) of the weight that had penetrated into the mixed liquid x 10.
  • the cone weight used was a standard cone as specified by the Japanese Industrial Standards, with a total mass of 102.5 g and a weight holder with a mass of 47.5 ⁇ 0.05 g.
  • buffer layer A ⁇ Production of fiber molded body (buffer layer A)>
  • glass wool uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer A.
  • the density of the obtained fiber molding (buffer layer A) was 0.17 g/ cm3 .
  • buffer layer B ⁇ Production of fiber molded body (buffer layer B)>
  • glass wool uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer B.
  • the density of the obtained fiber molding (buffer layer B) was 0.18 g/ cm3 .
  • buffer layer C ⁇ Production of fiber molded body (buffer layer C)>
  • glass wool uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer C.
  • the density of the obtained fiber molding (buffer layer C) was 0.20 g/ cm3 .
  • buffer layer D ⁇ Production of fiber molded body (buffer layer D)>
  • glass wool uncured wool (700 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer D.
  • the density of the obtained fiber molding (buffer layer D) was 0.21 g/ cm3 .
  • buffer layer E ⁇ Production of fiber molded body (buffer layer E)>
  • glass wool uncured wool (700 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer E.
  • the density of the obtained fiber molding (buffer layer E) was 0.23 g/ cm3 .
  • buffer layer F ⁇ Production of fiber molded body (buffer layer F)>
  • glass wool uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer F) was 0.24 g/ cm3 .
  • buffer layer G ⁇ Production of fiber molded body (buffer layer G)>
  • glass wool uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer G) was 0.27 g/ cm3 .
  • buffer layer H ⁇ Production of fiber molded body (buffer layer H)>
  • glass wool uncured wool (1000 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer H) was 0.30 g/ cm3 .
  • buffer layer I ⁇ Production of fiber molded body (buffer layer I)>
  • glass wool uncured wool (1000 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer I) was 0.33 g/ cm3 .
  • buffer layer J ⁇ Production of fiber molded body (buffer layer J)>
  • glass wool uncured wool (1200 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molded product (buffer layer J) was 0.36 g/ cm3 .
  • buffer layer K ⁇ Production of fiber molded body (buffer layer K)>
  • glass wool uncured wool (1200 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer K) was 0.40 g/ cm3 .
  • buffer layer L ⁇ Production of fiber molding (buffer layer L)>
  • glass wool uncured wool (1400 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer L) was 0.42 g/ cm3 .
  • buffer layer M ⁇ Production of fiber molded body (buffer layer M)>
  • glass wool uncured wool (1556 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer M) was 0.44 g/ cm3 .
  • buffer layer N ⁇ Production of fiber molded body (buffer layer N)>
  • glass wool uncured wool (1400 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer N) was 0.47 g/ cm3 .
  • buffer layer O ⁇ Production of fiber molded body (buffer layer O)>
  • glass wool uncured wool (1656 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer O) was 0.50 g/ cm3 .
  • buffer layer P ⁇ Production of fiber molded body (buffer layer P)>
  • glass wool uncured wool (1556 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter+: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer P) was 0.52 g/ cm3 .
  • buffer layer Q ⁇ Production of fiber molded body (buffer layer Q)>
  • glass wool uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 4.0 mm to produce a buffer layer Q.
  • the density of the obtained fiber molding (buffer layer Q) was 0.20 g/ cm3 .
  • buffer layer R ⁇ Production of fiber molded body (buffer layer R)>
  • glass wool uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer R) was 0.19 g/ cm3 .
  • buffer layer S ⁇ Production of fiber molded body (buffer layer S)>
  • glass wool uncured wool (1050 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass
  • the density of the obtained fiber molding (buffer layer S) was 0.26 g/ cm3 .
  • buffer layer T ⁇ Production of fiber molded body (buffer layer T)>
  • glass wool uncured wool (900 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.5 mm to produce a buffer layer T.
  • the density of the obtained fiber molding (buffer layer T) was 0.25 g/ cm3 .
  • buffer layer U ⁇ Production of fiber molded body (buffer layer U)>
  • glass wool uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.5 mm to produce a buffer layer U.
  • the density of the obtained fiber molding (buffer layer U) was 0.14 g/ cm3 .
  • buffer layer V ⁇ Production of fiber molded body (buffer layer V)>
  • glass wool uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 5.0 mm to produce buffer layer V.
  • the density of the obtained fiber molding (buffer layer V) was 0.10 g/ cm3 .
  • buffer layer W ⁇ Production of fiber molded body (buffer layer W)>
  • glass wool uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 5.0 mm to produce a buffer layer W.
  • the density of the obtained fiber molding (buffer layer W) was 0.12 g/ cm3 .
  • ⁇ Fiber molded body (buffer layer X)> Glass wool (uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 ⁇ m%) was impregnated with a thermoplastic binder (butadiene-methyl methacrylate (MBR) latex manufactured by DIC Corporation, product name "Lackstar DM-820" and heated for 7 minutes using a hot press machine at 180°C to evaporate the water in the latex, and a buffer layer X was compression molded to a thickness of 2.9 mm. The density of the obtained fiber molding (buffer layer X) was 0.18 g/ cm3 and the MBR content was 32 mass%.
  • MBR butadiene-methyl methacrylate
  • the density was 0.35 g/cm 3 .
  • ⁇ Organic foam (buffer layer Z)> Urethane foam (2880 g/m 2 , thickness 6 mm, product name "MicroFoam (trademark) PH-480-6T-RP") manufactured by Shengying New Material Technology (Changzhou) Co., Ltd. was used as the buffer layer Z. The density was 0.48 g/cm 3 .
  • thermal insulation layers A to E whether there is a compressed state that satisfies the formula (a1-1) and the formula (a1-2), a compressed state that satisfies the formula (a2-1) and the formula (a2-2), or a compressed state that satisfies the formula (a3-1) and the formula (a3-2), and for the buffer layers A to P, whether there is a compressed state that satisfies the formula (b1-1) and the formula (b1-2), a compressed state that satisfies the formula (b2-1) and the formula (b2-2), a compressed state that satisfies the formula (b3-1) and the formula (b3-2), or a compressed state that satisfies the formula (b4-1) and the formula (b4-2) was examined.
  • Table 1 and Tables 2-1 to 2-4 The results are shown in Table 1 and Tables 2-1 to 2-4.
  • Tables 3-1 and 3-2 Tables 4-1 and 4-2.
  • an upward arrow in Table 4-1 indicates that the content of the cell in which the arrow is written is the same as the content written in the cell above it.
  • the thermal conductivity of the heat insulating layers A to K was measured by the following method.
  • the thermal conductivity was measured in two ways, under conditions of 80°C and 2 MPa and 600°C and 2 MPa, in accordance with the contents described in the Japanese Industrial Standards JIS A 1412-2:1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method (HFM method)".
  • HFM method Heat flow meter method
  • alumina composite material ("RS-100", manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W/(m ⁇ K)
  • titanium plate thickness 0.2 mm
  • the thermal conductivity k1 of the thermal insulation layer was calculated from the temperature detected by each thermocouple after the temperature was stabilized, the thickness of the thermal insulation layer when compressed, and the thermal conductivity and thickness of the standard sample, using the following formula (I).
  • thermocouple 1 The thermal conductivity of the thermal insulation layer obtained is shown in Table 3-3.
  • k1 the thermal conductivity of the insulating layer [W/(m K)]
  • k2 the thermal conductivity of the standard plate [W/(m K)]
  • L1 is the thickness of the insulating layer when pressed
  • L2 is the thickness of the standard plate
  • ⁇ T1 the temperature difference between the temperature of the second thermocouple (thermocouple 2) and the temperature of the third thermocouple (thermocouple 3)
  • ⁇ T2 is the temperature difference between the temperature of the first thermocouple (thermocouple 1) and the temperature of the second thermocouple (thermocouple 2).
  • the thermal resistance of the insulating layer was calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 according to the following formula (II). The obtained thermal resistance of the insulating layer is shown in Table 3-3.
  • R1 L1/k1 (II) (In the formula, R1 is the thermal resistance of the insulating layer [( m2 ⁇ K)/W], k1 is the thermal conductivity of the insulating layer [W/(m ⁇ K)], and L1 is the thickness of the insulating layer when pressed.)
  • Example 1 The heat insulating layer B and the buffer layer A were laminated together, and the laminate was covered with a coating layer with a vent hole to produce a heat insulating material.
  • a polyethylene terephthalate (PET) shrink film manufactured by Mitsubishi Chemical Corporation, product name "Hishipet PX-40S", thickness 20 ⁇ m
  • PET polyethylene terephthalate
  • the shrink film was cut into a size 10% larger in area than the planar shape of the laminate, and the upper and lower films were welded around the laminate, and then a through hole for the ventilation hole was formed in the film with a needle or a laser, and the film was shrunk by heating it in a heating furnace at 95 ° C. for 15 seconds to obtain a heat insulating material according to Example 1.
  • the ventilation hole was formed so as to fully allow the flow of air between the inside of the coating
  • Example 2 to 16 The heat insulating materials were prepared in the same manner as in Example 1, except that the combinations of the heat insulating layer and the buffer layer were as shown in Table 5-1.
  • Example 17 to 25 The heat insulating materials were prepared in the same manner as in Example 1, except that the combinations of the heat insulating layer and the buffer layer were as shown in Table 5-2.
  • Tables 5-1 and 5-4 also show the value (strain difference (Xhp)) obtained by subtracting the compressive strain at a pressure of 0.34 MPa during the compression process from the compressive strain at a pressure of 3.45 MPa, and the value (strain difference (Xhr)) obtained by subtracting the compressive strain in the above-mentioned compressed state during the compression release process (i.e., the compressed state that has the same displacement as the compressive stress of 0.34 MPa during the compression process) from the compressive strain at a pressure of 3.45 MPa.
  • ⁇ Loading-unloading test 2 Low pressure conditions>
  • a load-unload test was carried out by the following method, and the thickness and compressive strain of the insulating material were measured at each of the following points.
  • the heat insulating material was compressed at a compression speed of 0.5 mm/min until the compressive stress reached 1.39 MPa, and then the heat insulating material was released at a compression speed of 0.5 mm/min until the compressive stress reached zero.
  • a stress-strain curve (S-S curve) that shows a schematic representation of the above loading-unloading test is shown in FIG.
  • Tables 5-2 and 5-3 also show the value (strain difference (Xlp)) obtained by subtracting the compressive strain at a pressure of 0.03 MPa during the compression process from the compressive strain at a pressure of 1.39 MPa, and the value (strain difference (Xlr)) obtained by subtracting the compressive strain in the above-mentioned compressed state during the compression release process (i.e., the compressed state that has the same displacement as the compressive stress of 0.03 MPa during the compression process) from the compressive strain at a pressure of 1.39 MPa.
  • the insulating materials of Examples 1 to 16 which have a buffer layer that gives a stress-strain curve that passes through at least region (b1) in a compression test alone, all had a strain difference (Xhp) during the compression process of 15% or more and a strain difference (Xhr) during the compression release process of 5% in a loading-unloading test 1 under high pressure conditions, and the thickness changed appropriately with respect to pressure.
  • the total point of the S-S curve shape of all of these insulating materials was 4.0 or more.
  • insulation materials are combinations of an insulation layer that gives a stress-strain curve that passes through region (a6) and a buffer layer that gives a stress-strain curve that passes through region (b8), and all of the total points of the S-S curve shapes were 6.0 or more, and showed excellent compression characteristics, with a strain difference (Xlp) during the compression process of 30% or more and a strain difference (Xlr) during the compression-release process of 6% or more.
  • Table 5-3 below shows the results of evaluating the insulation materials of Examples 1 to 16 through load-unload test 2 (low pressure conditions), and Table 5-4 below shows the results of evaluating the insulation materials of Examples 17 to 25 through load-unload test 1 (high pressure conditions).

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Abstract

Provided is a heat-insulating material comprising: a heat-insulating layer including inorganic particles; and a buffer layer made of a fibrous molded body including fibers, or a foam molded body including foam. The buffer layer is a layer that can be in a compression state with a compressive strain value xB [%] and a compressive stress value yB [MPa] satisfying the following formula (b1-1) and formula (b1-2) when a compression test is performed only on the buffer layer at a compression speed of 0.5 mm/min.　Formula (b1-1): 0.50 ≤ yB ≤ 3.45 Formula (b1-2): 0.30xB - 18.68 ≤ yB ≤ 0.20xB - 0.48

Description

断熱材Insulation
　本発明は、断熱材に関し、より詳しくは断熱層と緩衝層とを有する断熱材に関する。
　本出願は、２０２２年１０月３１日に出願された日本国特許出願２０２２－１７５１１４号に基づく優先権を主張し、その出願の全内容は本明細書中に参照として組み入れられている。 The present invention relates to a thermal insulation material, and more particularly to a thermal insulation material having a thermal insulation layer and a buffer layer.
This application claims priority based on Japanese Patent Application No. 2022-175114, filed on October 31, 2022, the entire contents of which are incorporated herein by reference.
　電気自動車（ＥＶ）、ハイブリッド自動車（ＨＥＶ）、プラグインハイブリッド自動車（ＰＥＶ）、燃料電池車（ＦＣＶ）等の電動自動車の電源としてリチウムイオン二次電池等の非水系電解質二次電池の利用が進んでおり、これらの用途では非常に高い出力と容量が必要となるため、バッテリーセル（単電池）を集積したバッテリーモジュールまたはバッテリーパックの形態で使用されている。また、リチウムイオン二次電池のバッテリーパックには、安全性等を確保するために様々な機能を持った部材を利用することが検討されており、例えば一部のセルが異常に発熱してしまった場合でも熱暴走を生じさせないようにするために、セル間に断熱材を配置することが行われている。 Non-aqueous electrolyte secondary batteries such as lithium-ion secondary batteries are increasingly being used as power sources for electrically powered vehicles such as electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PEVs), and fuel cell vehicles (FCVs). Because these applications require extremely high output and capacity, they are used in the form of battery modules or battery packs that integrate battery cells (single cells). In addition, in order to ensure safety, etc., it is being considered to use components with various functions in lithium-ion secondary battery battery packs. For example, insulating materials are being placed between cells to prevent thermal runaway even if some cells become abnormally hot.
　リチウムイオン二次電池のセルは、充電による膨張と放電による収縮を繰り返すことが知られており、その原因と対策に関する研究も進んでいる。例えば非特許文献１には、シリコン粒子と電解液等との副反応による酸化被膜が原因であることが記載されており、その対策として新たな酸化防止被膜を用いることで材料の不可逆な膨張が抑制され、これにより電極膨張とサイクル劣化の双方を抑制している。また、充放電に伴う電池セルの膨張および収縮が大きい二次電池に対して、例えば、非特許文献２には、弾性率を調整したバインダーを用いることで、電極の膨張を抑制し、サイクル特性が良好となることが開示されている。 It is known that the cells of lithium-ion secondary batteries repeatedly expand when they are charged and contract when they are discharged, and research into the causes and countermeasures is also progressing. For example, Non-Patent Document 1 describes that the cause is an oxide coating caused by a side reaction between silicon particles and the electrolyte, etc., and as a countermeasure, a new anti-oxidation coating is used to suppress the irreversible expansion of the material, thereby suppressing both electrode expansion and cycle deterioration. Furthermore, for secondary batteries, which have large expansion and contraction of battery cells due to charging and discharging, Non-Patent Document 2, for example, discloses that the use of a binder with an adjusted elastic modulus suppresses electrode expansion and improves cycle characteristics.
　また、特許文献１には、二次電池の電極体から電極体の積層方向に荷重を受ける弾性体においても圧力吸収の役割があり、各部材の圧縮弾性率を規定することで、ハイレート充放電における抵抗増加および充放電サイクルにおける容量低下を抑制できることが開示されている。 Patent Document 1 also discloses that the elastic body, which receives a load from the electrode body of the secondary battery in the stacking direction of the electrode body, also plays a role in absorbing pressure, and that by specifying the compressive elastic modulus of each member, it is possible to suppress the increase in resistance during high-rate charging and discharging and the decrease in capacity during charge and discharge cycles.
日本国特許出願公開２０２１－１１４３６１号公報Japanese Patent Application Publication No. 2021-114361 カナダ国特許出願公開第１１９０２７９号明細書Canadian Patent Application Publication No. 1190279
　前述のようにリチウムイオン二次電池のセルは、充電による膨張と放電による収縮を繰り返し、さらに不可逆的な膨張も生じるため、セルを集積するバッテリーパックまたは該バッテリーパックを構成するバッテリーモジュールにおいては、セルの集積方向における寸法変化や発生圧力等を考慮することが必要になる。また、リチウムイオン二次電池のセルは、セル自体にある程度の圧力がかかった方が、電池としての効率が向上することも報告されている（例えば、特許文献２、非特許文献３、非特許文献４）。したがって、バッテリーパック等のセル間に配置される断熱材は、熱暴走等を抑制するための断熱性を奏するとともに、セルの膨張と収縮の繰り返し等に対して相応の厚みを変動でき、さらに適度な応力を発生しうる緩衝性を備えることが好ましい。 As mentioned above, the cells of a lithium-ion secondary battery repeatedly expand when charged and contract when discharged, and also undergo irreversible expansion. Therefore, in a battery pack that integrates the cells, or in a battery module that constitutes the battery pack, it is necessary to take into consideration the dimensional change in the direction in which the cells are integrated and the generated pressure. It has also been reported that the efficiency of a lithium-ion secondary battery cell is improved when a certain amount of pressure is applied to the cell itself (for example, Patent Document 2, Non-Patent Document 3, Non-Patent Document 4). Therefore, it is preferable that the insulating material arranged between the cells of a battery pack or the like has insulating properties to suppress thermal runaway, etc., can change its thickness accordingly in response to repeated expansion and contraction of the cells, and has cushioning properties that can generate appropriate stress.
　本発明は、優れた断熱性と緩衝性、特にバッテリーパック等のセル間に配置される断熱材として利用したときに好適な断熱性と緩衝性を備えた断熱材を提供することを目的とする。 The present invention aims to provide an insulating material that has excellent heat insulation and shock-absorbing properties, particularly suitable for use as an insulating material placed between cells of a battery pack, etc.
　この明細書により提供される断熱材は、無機粒子を含んでなる断熱層と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層とを有する。上記緩衝層は、該緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ１－１）および下記式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である。上記圧縮試験において上記式（ｂ１－１）および式（ｂ１－２）を同時に満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる緩衝層を採用することにより、セルの膨張と収縮の繰り返し等に対して厚みが適切に変動し、さらに好適な応力を発生する断熱材を実現することができる。
　式（ｂ１－１）：０．５０≦ｙＢ≦３．４５
　式（ｂ１－２）：０．３０ｘＢ－１８．６８≦ｙＢ≦０．２０ｘＢ－０．４８ The heat insulating material provided by this specification has a heat insulating layer containing inorganic particles, and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam. The buffer layer is a layer that can generate a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min. By adopting a buffer layer that can generate a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that simultaneously satisfy the above formula (b1-1) and formula (b1-2) in the compression test, it is possible to realize a heat insulating material whose thickness changes appropriately with repeated expansion and contraction of cells and which generates a suitable stress.
Formula (b1-1): 0.50≦y B ≦3.45
Formula (b1-2): 0.30x B -18.68≦y B ≦0.20x B -0.48
　ここに開示される断熱材のいくつかの態様において、上記緩衝層は、上記圧縮試験を行ったときに、下記式（ｂ２－１）および下記式（ｂ２－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。緩衝層が上記圧縮状態の生じうる層であると、好適な緩衝性を確保しやすくなる。
　式（ｂ２－１）：１．００≦ｙＢ≦３．００
　式（ｂ２－２）：０．２０ｘＢ－１１．００≦ｙＢ≦０．１０ｘＢ In some embodiments of the thermal insulation material disclosed herein, the buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b2-1) and (b2-2) when the compression test is performed. When the buffer layer is a layer that can generate the above compressed state, it becomes easier to ensure suitable cushioning properties.
Formula (b2-1): 1.00≦y B ≦3.00
Formula (b2-2): 0.20x B -11.00 ≦ y B ≦ 0.10x B
　いくつかの態様において、上記緩衝層は、上記圧縮試験を行ったときに、下記式（ｂ３－１）および下記式（ｂ３－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。
　式（ｂ３－１）：１．５０≦ｙＢ≦３．００
　式（ｂ３－２）：０．１５ｘＢ－７．５０≦ｙＢ≦０．１０ｘＢ－１．００ In some embodiments, it is more preferable that the buffer layer is a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b3-1) and (b3-2) when the compression test is performed. If the buffer layer is a layer that can generate the above compressed state, more suitable cushioning properties can be easily ensured.
Formula (b3-1): 1.50≦y B ≦3.00
Formula (b3-2): 0.15x B -7.50≦y B ≦0.10x B -1.00
　いくつかの態様において、上記緩衝層は、上記圧縮試験を行ったときに、下記式（ｂ４－１）および下記式（ｂ４－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じる層であることがさらに好ましい。緩衝層が上記圧縮状態の生じうる層であると、さらに好適な緩衝性を確保しやすくなる。
　式（ｂ４－１）：２．００≦ｙＢ≦２．５０
　式（ｂ４－２）：０．１０ｘＢ－３．５０≦ｙＢ≦０．１０ｘＢ－１．５０ In some embodiments, it is more preferable that the buffer layer is a layer that, when the compression test is performed, generates a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b4-1) and formula (b4-2): When the buffer layer is a layer that can generate the above compressed state, it becomes easier to ensure more suitable cushioning properties.
Formula (b4-1): 2.00≦y B ≦2.50
Formula (b4-2): 0.10x B -3.50≦y B ≦0.10x B -1.50
　ここに開示される断熱材のいくつかの態様において、上記断熱層は、上記断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ１－１）および下記式（ａ１－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。ここに開示されるいずれかの緩衝層と組み合わせて断熱材を構築するために使用される断熱層として、上記圧縮試験において上記式（ａ１－１）および上記式（ａ１－２）を同時に満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる断熱層を採用することにより、上記断熱材において好適な断熱性および緩衝性を発揮することができる。
　式（ａ１－１）：０．５０≦ｙＡ≦３．４５
　式（ａ１－２）：０．１２ｘＡ－２．４５≦ｙＡ In some embodiments of the thermal insulation material disclosed herein, the thermal insulation layer is preferably a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a1-1) and formula (a1-2) when a compression test is performed on the thermal insulation layer alone at a compression speed of 0.5 mm/min. By adopting a thermal insulation layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that simultaneously satisfy the above formula (a1-1) and the above formula (a1-2) in the compression test as the thermal insulation layer used to construct a thermal insulation material in combination with any of the buffer layers disclosed herein, the thermal insulation material can exhibit suitable thermal insulation and cushioning properties.
Formula (a1-1): 0.50≦y A ≦3.45
Formula (a1-2): 0.12x A -2.45≦y A
　いくつかの態様において、上記断熱層は、上記圧縮試験を行ったときに、下記式（ａ２－１）および下記式（ａ２－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。
　式（ａ２－１）：１．００≦ｙＡ≦３．００
　式（ａ２－２）：０．２０ｘＡ－３．００≦ｙＡ In some embodiments, the heat insulating layer is more preferably a layer that can generate a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a2-1) and formula (a2-2) when the compression test is performed. When the heat insulating layer is a layer that can generate the above compressed state, better heat insulation is more easily ensured.
Formula (a2-1): 1.00≦y A ≦3.00
Formula (a2-2): 0.20xA -3.00≦ yA
　いくつかの態様において、上記断熱層は、上記圧縮試験を行ったときに、下記式（ａ３－１）および下記式（ａ３－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがさらに好ましい。断熱層が上記圧縮状態の生じうる層であると、さらに良好な断熱性を確保しやすくなる。
　式（ａ３－１）：１．５０≦ｙＡ≦２．５０
　式（ａ３－２）：０．２０ｘＡ－１．５０≦ｙＡ In some embodiments, it is more preferable that the heat insulating layer is a layer that can generate a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a3-1) and formula (a3-2) when the compression test is performed. If the heat insulating layer is a layer that can generate the above compressed state, it becomes easier to ensure even better heat insulation.
Formula (a3-1): 1.50≦y A ≦2.50
Formula (a3-2): 0.20xA -1.50≦ yA
　いくつかの態様において、上記断熱層は、上記無機粒子として二酸化ケイ素粒子を含む層であることが好ましい。ここに開示される断熱材は、二酸化ケイ素粒子を含む断熱層と上記緩衝層とを備える構成で好ましく実施することができる。上記二酸化ケイ素粒子としては、乾式シリカ、湿式シリカ、およびシリカエアロゲルからなる群より選択される少なくとも１種を好ましく採用し得る。上記乾式シリカの一好適例として親水性フュームドシリカが挙げられる。 In some embodiments, the insulating layer is preferably a layer containing silicon dioxide particles as the inorganic particles. The insulating material disclosed herein can be preferably implemented in a configuration including an insulating layer containing silicon dioxide particles and the buffer layer. As the silicon dioxide particles, at least one type selected from the group consisting of dry silica, wet silica, and silica aerogel can be preferably used. One suitable example of the dry silica is hydrophilic fumed silica.
　いくつかの態様において、上記断熱層は、上記無機粒子および無機繊維を含む混合物を成形した成形体であることが好ましい。ここに開示される断熱材は、かかる成型体である断熱層と上記緩衝層とを備える構成で好ましく実施することができる。 In some embodiments, the insulating layer is preferably a molded body formed from a mixture containing the inorganic particles and inorganic fibers. The insulating material disclosed herein can be preferably implemented in a configuration including an insulating layer that is such a molded body and the buffer layer.
　ここに開示される断熱材は、バッテリーモジュールのセル間に配置される態様で好ましく使用することができる。特に、リチウムイオンバッテリーモジュールのセル間に配置される断熱材として好適である。 The insulating material disclosed herein can be preferably used in a form in which it is disposed between the cells of a battery module. It is particularly suitable as an insulating material disposed between the cells of a lithium-ion battery module.
　なお、本明細書に記載された各要素を適宜組み合わせたものも、本件特許出願によって特許による保護を求める発明の範囲に含まれ得る。 In addition, any suitable combination of the elements described in this specification may be included within the scope of the invention for which patent protection is sought through this patent application.
緩衝層のみに対して圧縮試験を行ったときの応力－ひずみ曲線（Ｓ－Ｓカーブ）と式（ｂ１－１）および式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の領域を表したグラフである。1 is a graph showing a stress-strain curve (SS curve) when a compression test is performed on only the buffer layer, and a region of compressive strain value x B [%] and compressive stress value y B [MPa] that satisfies formulas (b1-1) and (b1-2). 一態様に係る断熱材がセル間に配置されたバッテリーモジュールの一例を模式的に示す斜視図である。FIG. 1 is a perspective view showing a schematic diagram of an example of a battery module in which an insulating material according to one embodiment is disposed between cells. 図２のII－II線断面図である。FIG. 3 is a cross-sectional view taken along line II-II of FIG. 2. 一態様に係る断熱材を模式的に示す斜視図である。FIG. 1 is a perspective view showing a schematic diagram of an insulating material according to one embodiment. 図４のIV－IV線断面図である。4 is a cross-sectional view taken along line IV-IV of FIG. 他の一態様に係る断熱材を模式的に示す断面図である。FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment. 他の一態様に係る断熱材を模式的に示す断面図である。FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment. 他の一態様に係る断熱材を模式的に示す断面図である。FIG. 2 is a cross-sectional view showing a schematic diagram of a heat insulating material according to another embodiment. 断熱層Ａの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the insulating layer A. 断熱層Ｂの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the insulating layer B. 断熱層Ｃの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the insulating layer C. 断熱層Ｄ，Ｅの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。4 shows the stress-strain curves (SS curves) of the insulating layers D and E. 断熱層Ｆ，Ｇ，Ｈの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。4 shows the stress-strain curves (SS curves) of the insulating layers F, G, and H. 断熱層Ｉの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the insulating layer I. 断熱層Ｊ，Ｋの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the insulating layers J and K. 緩衝層Ａの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer A. 緩衝層Ｂの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer B. 緩衝層Ｃの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer C. 緩衝層Ｄの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer D. 緩衝層Ｅの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer E. 緩衝層Ｆの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer F. 緩衝層Ｇ，Ｉの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the buffer layers G and I. 緩衝層Ｈ，Ｊの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of buffer layers H and J. 緩衝層Ｍの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。2 is a stress-strain curve (SS curve) of the buffer layer M. 緩衝層Ｋ，Ｎ，Ｏの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of buffer layers K, N, and O. 緩衝層Ｌ，Ｐの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。2 shows stress-strain curves (SS curves) of the buffer layers L and P. 緩衝層Ｑ，Ｔの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the buffer layers Q and T. 緩衝層Ｒ，Ｓの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the buffer layers R and S. 緩衝層Ｕ，Ｖ，Ｗの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the buffer layers U, V, and W. 緩衝層Ｘ，Ｙの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 shows stress-strain curves (SS curves) of the buffer layers X and Y. 緩衝層Ｚの応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (SS curve) of the buffer layer Z. 載荷－除荷試験１（高圧力条件）を模式的に表した応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (S-S curve) that shows a schematic diagram of loading-unloading test 1 (high pressure condition). 載荷－除荷試験２（低圧力条件）を模式的に表した応力－ひずみ曲線（Ｓ－Ｓカーブ）である。1 is a stress-strain curve (S-S curve) showing a schematic diagram of loading-unloading test 2 (low pressure condition).
　以下、本発明の好適な実施形態を説明する。なお、本明細書において特に言及している事項以外の事柄であって本発明の実施に必要な事柄は、本明細書に記載された発明の実施についての教示と出願時の技術常識とに基づいて当業者に理解され得る。本発明は、本明細書に開示されている内容と当該分野における技術常識とに基づいて実施することができる。また、以下の図面において、同じ作用を奏する部材・部位には同じ符号を付して説明することがあり、重複する説明は省略または簡略化することがある。また、図面に記載の実施形態は、本発明を明瞭に説明するために模式化されており、実際に提供される製品のサイズや縮尺を必ずしも正確に表したものではない。 Below, preferred embodiments of the present invention are described. Note that matters necessary for implementing the present invention other than those specifically mentioned in this specification can be understood by a person skilled in the art based on the teachings on implementing the invention described in this specification and the common general technical knowledge at the time of filing. The present invention can be implemented based on the contents disclosed in this specification and the common general technical knowledge in the relevant field. In addition, in the drawings below, components and parts that perform the same function may be described using the same reference numerals, and duplicate descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are schematic in order to clearly explain the present invention, and do not necessarily accurately represent the size or scale of the product actually provided.
　この明細書により開示される断熱材（以下、「断熱材」と略す場合がある。）は、無機粒子を含んでなる断熱層（以下、「断熱層」と略す場合がある。）と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層（以下、「緩衝層」と略す場合がある。）とを有する。 The heat insulating material (hereinafter sometimes abbreviated as "heat insulating material") disclosed in this specification has a heat insulating layer (hereinafter sometimes abbreviated as "heat insulating layer") containing inorganic particles, and a buffer layer (hereinafter sometimes abbreviated as "buffer layer") consisting of a fiber molded body containing fibers or a foam molded body containing a foam.
　いくつかの態様に係る断熱材は、上記緩衝層が、該緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ１－１）および下記式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることを特徴とする。
　式（ｂ１－１）：０．５０≦ｙＢ≦３．４５
　式（ｂ１－２）：０．３０ｘＢ－１８．６８≦ｙＢ≦０．２０ｘＢ－０．４８ In some embodiments, the thermal insulation material is characterized in that the buffer layer is a layer that can produce a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min.
Formula (b1-1): 0.50≦y B ≦3.45
Formula (b1-2): 0.30x B -18.68≦y B ≦0.20x B -0.48
　他のいくつかの態様に係る断熱材は、上記緩衝層が、該緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ５－１）および下記式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることを特徴とする。
　式（ｂ５－１）：０．１０≦ｙＢ≦１．３９
　式（ｂ５－２）：０．１２９ｘＢ－９．５７５≦ｙＢ≦０．１２９ｘＢ－１．１９ In some other embodiments of the thermal insulation material, the buffer layer is a layer that can produce a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min.
Formula (b5-1): 0.10≦y B ≦1.39
Formula (b5-2): 0.129x B -9.575≦y B ≦0.129x B -1.19
　本発明者らは、断熱性と緩衝性をそなえた断熱材について鋭意検討を重ねた結果、断熱層に加えて、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層を配置し、さらに上記緩衝層として、圧縮試験において特定の圧縮状態を生じうる層を採用することにより、セルの膨張と収縮の繰り返し等に対して厚みが適切に変動し、さらに好適な応力を発生する断熱材となることを見出した。 As a result of extensive research into insulating materials that combine thermal insulation and cushioning properties, the inventors discovered that by providing a cushioning layer made of a fiber molded body containing fibers or a foamed molded body containing foam in addition to the insulating layer, and by using a layer that can produce a specific compression state in a compression test as the cushioning layer, it is possible to obtain an insulating material whose thickness changes appropriately in response to repeated cell expansion and contraction, and which generates an appropriate stress.
　以下、「圧縮試験」、「圧縮ひずみ値」、「圧縮応力値」等について詳細に説明する。 　Below, we will explain in detail about "compression test", "compression strain value", "compression stress value", etc.
　この明細書において「圧縮試験」とは、試験対象に対して圧縮力（荷重）を加えていき、試験対象の変形や破損が生じるまでの圧縮強度等を測定する試験を意味する。なお、圧縮試験は、精密万能試験機オートグラフ等の市販の試験機を利用して適宜実施することができる試験である。これらの試験機と制御ソフトウェアでは、試験条件として「圧縮速度」を設定することができ、一般的には、試験対象を圧縮していく過程の圧縮変位と圧縮強度が逐次測定されて、「圧縮ひずみ」、「圧縮応力」、応力－ひずみ曲線（Ｓ－Ｓカーブ）等が自動で出力されるようになっている。また、この明細書により開示される断熱材は、断熱層と緩衝層を含むものであるが、圧縮試験自体は緩衝層単独や断熱層単独の状態を試験対象とした単体試験で考えるものとする。 In this specification, "compression test" refers to a test in which a compressive force (load) is applied to a test object, and the compressive strength, etc. of the test object is measured until the test object is deformed or broken. The compression test can be appropriately performed using a commercially available testing machine such as a precision universal testing machine Autograph. With these testing machines and control software, the "compression speed" can be set as a test condition, and generally, the compressive displacement and compressive strength of the test object are measured sequentially as the test object is compressed, and "compressive strain," "compressive stress," stress-strain curves (S-S curves), etc. are automatically output. In addition, the insulation material disclosed in this specification includes an insulation layer and a buffer layer, but the compression test itself is considered to be a standalone test in which the buffer layer alone or the insulation layer alone is the test object.
　この明細書により開示される断熱材のいくつかの態様において、該断熱材における緩衝層は、前述の圧縮試験を行ったときに、「下記式（ｂ１－１）および下記式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」である。これは、前述の圧縮試験によって生じる圧縮状態の中で、「圧縮ひずみ値ｘＢ［％］」と、これに対応する「圧縮応力値ｙＢ［ＭＰａ］」として、下記式（ｂ１－１）と下記式（ｂ１－２）を同時に満たす数値がある緩衝層である、ということを意味する。
　式（ｂ１－１）：０．５０≦ｙＢ≦３．４５
　式（ｂ１－２）：０．３０ｘＢ－１８．６８≦ｙＢ≦０．２０ｘＢ－０．４８ In some embodiments of the thermal insulation material disclosed in this specification, the buffer layer in the thermal insulation material is a "layer in which a compressed state of compressive strain value x B [%] and compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) can be generated when the above-mentioned compression test is performed. This means that the buffer layer has values that simultaneously satisfy the following formulas (b1-1) and (b1-2) for "compressive strain value x B [%]" and the corresponding "compressive stress value y B [MPa]" in the compressed state generated by the above-mentioned compression test.
Formula (b1-1): 0.50≦y B ≦3.45
Formula (b1-2): 0.30x B -18.68≦y B ≦0.20x B -0.48
　なお、式（ｂ１－１）は、図１においてｘ軸に平行な２つの直線の内側を、式（ｂ１－２）は、図１において斜めに伸びる２つの直線の内側を表しており、式（ｂ１－１）と式（ｂ１－２）を同時に満たす圧縮ひずみ値ｘＢと圧縮応力値ｙＢは、これらの直線に囲まれる領域（以下、領域（ｂ１）ともいう。）に存在することになる。そのため、「式（ｂ１－１）および式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」とは、圧縮試験によって得られる圧縮ひずみ値ｘＢと圧縮応力値ｙＢの組合せの中で、少なくとも一組がこの領域（ｂ１）内に属している層であるといえる。また、圧縮試験の具体的な測定値として領域（ｂ１）内に属する組合せがなかったとしても、圧縮ひずみ値ｘＢと圧縮応力値ｙＢの近似曲線を結んだ場合に、その近似曲線が領域（ｂ１）内を通過する場合も、領域（ｂ１）内に属する層であるとみなすことができる。すなわち、「式（ｂ１－１）および式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」とは、圧縮試験によって得られるいわゆる「応力－ひずみ曲線（Ｓ－Ｓカーブ）」が領域（ｂ１）を通過する層であるといえる。 In addition, formula (b1-1) represents the inside of two straight lines parallel to the x-axis in Fig. 1, and formula (b1-2) represents the inside of two straight lines extending diagonally in Fig. 1, and the compressive strain value xB and compressive stress value yB that simultaneously satisfy formula (b1-1) and formula (b1-2) are present in the region surrounded by these straight lines (hereinafter also referred to as region (b1)). Therefore, "a layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formula (b1-1) and formula (b1-2) can occur" can be said to be a layer in which at least one combination of compressive strain value xB and compressive stress value yB obtained by a compression test belongs to this region (b1). Furthermore, even if there is no combination that falls within region (b1) as a specific measured value in a compression test, if an approximation curve of compressive strain value xB and compressive stress value yB passes through region (b1), the layer can be considered to belong to region (b1). In other words, a "layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formulas (b1-1) and (b1-2) can occur" can be said to be a layer in which the so-called "stress-strain curve (S-S curve)" obtained by a compression test passes through region (b1).
　なお、式（ｂ１－２）の左辺「０．３０ｘＢ－１８．６８」は、圧縮ひずみ値が「６５％」で圧縮応力値が「０．５０ＭＰａ」となる点と、圧縮ひずみ値が「７５％」で圧縮応力値が「３．４５ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．３０」と切片の「－１８．６８」が算出される。したがって、圧縮ひずみ値は「％」単位の数値を、圧縮応力値は「ＭＰａ」単位の数値を利用するものとする。一方、式（ｂ１－２）の右辺「０．２０ｘＢ－０．４８」は、圧縮ひずみ値が「５％」で圧縮応力値が「０．５０ＭＰａ」となる点と、圧縮ひずみ値が「２０％」で圧縮応力値が「３．４５ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．２０」と切片の「－０．４８」が算出される。 The left side of formula (b1-2) "0.30x B -18.68" represents a straight line connecting the point where the compressive strain value is "65%" and the compressive stress value is "0.50 MPa" and the point where the compressive strain value is "75%" and the compressive stress value is "3.45 MPa", and the slope of "0.30" and the intercept of "-18.68" are calculated from these points. Therefore, the compressive strain value is expressed in "%", and the compressive stress value is expressed in "MPa". On the other hand, the right-hand side of formula (b1-2), "0.20x B -0.48", represents a straight line connecting the point where the compressive strain value is "5%" and the compressive stress value is "0.50 MPa" and the point where the compressive strain value is "20%" and the compressive stress value is "3.45 MPa". From these points, the slope of "0.20" and the intercept of "-0.48" are calculated.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ２－１）および下記式（ｂ２－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。すなわち、上記圧縮試験により得られる応力－ひずみ曲線が、式（ｂ２－１）と式（ｂ２－２）によって囲まれた領域（領域（ｂ２））を通過することが好ましい。
　式（ｂ２－１）：１．００≦ｙＢ≦３．００
　式（ｂ２－２）：０．２０ｘＢ－１１．００≦ｙＢ≦０．１０ｘＢ
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 The buffer layer is preferably a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b2-1) and (b2-2) when the above-mentioned compression test is carried out. In other words, it is preferable that the stress-strain curve obtained by the above-mentioned compression test passes through the region enclosed by formulae (b2-1) and (b2-2) (region (b2)).
Formula (b2-1): 1.00≦y B ≦3.00
Formula (b2-2): 0.20x B -11.00 ≦ y B ≦ 0.10x B
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ２－２）の左辺「０．２０ｘＢ－１１．００」は、圧縮ひずみ値が「６０％」で圧縮応力値が「１．００ＭＰａ」となる点と、圧縮ひずみ値が「７０％」で圧縮応力値が「３．００ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．２０」と切片の「－１１．００」が算出される。一方、式（ｂ２－２）の右辺「０．１０ｘＢ」は、圧縮ひずみ値が「１０％」で圧縮応力値が「１．００ＭＰａ」となる点と、圧縮ひずみ値が「３０％」で圧縮応力値が「３．００ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１０」と切片の「０」が算出される。 The left side of formula (b2-2) "0.20x B -11.00" represents a straight line connecting the point where the compressive strain value is "60%" and the compressive stress value is "1.00 MPa" and the point where the compressive strain value is "70%" and the compressive stress value is "3.00 MPa", and the slope "0.20" and the intercept "-11.00" are calculated from these points. On the other hand, the right side of formula (b2-2) "0.10x B " represents a straight line connecting the point where the compressive strain value is "10%" and the compressive stress value is "1.00 MPa" and the point where the compressive strain value is "30%" and the compressive stress value is "3.00 MPa", and the slope "0.10" and the intercept "0" are calculated from these points.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ３－１）および下記式（ｂ３－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。
　式（ｂ３－１）：１．５０≦ｙＢ≦３．００
　式（ｂ３－２）：０．１５ｘＢ－７．５０≦ｙＢ≦０．１０ｘＢ－１．００
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 The buffer layer is preferably a layer that can generate a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b3-1) and (b3-2) when the above-mentioned compression test is carried out.
Formula (b3-1): 1.50≦y B ≦3.00
Formula (b3-2): 0.15x B -7.50≦y B ≦0.10x B -1.00
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ３－２）の左辺「０．１５ｘＢ－７．５０」は、圧縮ひずみ値が「６０％」で圧縮応力値が「１．５０ＭＰａ」となる点と、圧縮ひずみ値が「７０％」で圧縮応力値が「３．００ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１５」と切片の「－７．５０」が算出される。一方、式（ｂ３－２）の右辺「０．１０ｘＢ－１．００」は、圧縮ひずみ値が「２５％」で圧縮応力値が「１．５０ＭＰａ」となる点と、圧縮ひずみ値が「４０％」で圧縮応力値が「３．００ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１０」と切片の「－１．００」が算出される。 The left side of formula (b3-2) "0.15x B -7.50" represents a straight line connecting the point where the compressive strain value is "60%" and the compressive stress value is "1.50 MPa" and the point where the compressive strain value is "70%" and the compressive stress value is "3.00 MPa", and the slope "0.15" and the intercept "-7.50" are calculated from these points. On the other hand, the right side of formula (b3-2) "0.10x B -1.00" represents a straight line connecting the point where the compressive strain value is "25%" and the compressive stress value is "1.50 MPa" and the point where the compressive strain value is "40%" and the compressive stress value is "3.00 MPa", and the slope "0.10" and the intercept "-1.00" are calculated from these points.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ４－１）および下記式（ｂ４－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。
　式（ｂ４－１）：２．００≦ｙＢ≦２．５０
　式（ｂ４－２）：０．１０ｘＢ－３．５０≦ｙＢ≦０．１０ｘＢ－１．５０
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 It is more preferable that the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b4-1) and (b4-2) when the above-mentioned compression test is carried out.
Formula (b4-1): 2.00≦y B ≦2.50
Formula (b4-2): 0.10x B -3.50≦y B ≦0.10x B -1.50
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ４－２）の左辺「０．１０ｘＢ－３．５０」は、圧縮ひずみ値が「５５％」で圧縮応力値が「２．００ＭＰａ」となる点と、圧縮ひずみ値が「６０％」で圧縮応力値が「２．５０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１０」と切片の「－３．５０」が算出される。一方、式（ｂ４－２）の右辺「０．１０ｘＢ－１．５０」は、圧縮ひずみ値が「３５％」で圧縮応力値が「２．００ＭＰａ」となる点と、圧縮ひずみ値が「４０％」で圧縮応力値が「２．５０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１０」と切片の「－１．５０」が算出される。 The left side of formula (b4-2) "0.10x B -3.50" represents a straight line connecting the point where the compressive strain value is "55%" and the compressive stress value is "2.00 MPa" and the point where the compressive strain value is "60%" and the compressive stress value is "2.50 MPa", and the slope "0.10" and the intercept "-3.50" are calculated from these points. On the other hand, the right side of formula (b4-2) "0.10x B -1.50" represents a straight line connecting the point where the compressive strain value is "35%" and the compressive stress value is "2.00 MPa" and the point where the compressive strain value is "40%" and the compressive stress value is "2.50 MPa", and the slope "0.10" and the intercept "-1.50" are calculated from these points.
　また、この明細書により開示される断熱材の他のいくつかの態様において、該断熱材における緩衝層は、前述の圧縮試験を行ったときに、「下記式（ｂ５－１）および下記式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」であり得る。これは、前述の圧縮試験によって生じる圧縮状態の中で、「圧縮ひずみ値ｘＢ［％］」と、これに対応する「圧縮応力値ｙＢ［ＭＰａ］」として、下記式（ｂ５－１）と下記式（ｂ５－２）を同時に満たす数値がある緩衝層である、ということを意味する。
　式（ｂ５－１）：０．１０≦ｙＢ≦１．３９
　式（ｂ５－２）：０．１２９ｘＢ－９．５７５≦ｙＢ≦０．１２９ｘＢ－１．１９ In some other embodiments of the thermal insulation material disclosed in this specification, the buffer layer in the thermal insulation material may be "a layer in which a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) can be generated when the above-mentioned compression test is performed. This means that the buffer layer has values that simultaneously satisfy the following formula (b5-1) and formula (b5-2) as the "compressive strain value x B [%]" and the corresponding "compressive stress value y B [MPa]" in the compressed state generated by the above-mentioned compression test.
Formula (b5-1): 0.10≦y B ≦1.39
Formula (b5-2): 0.129x B -9.575≦y B ≦0.129x B -1.19
　なお、式（ｂ５－１）は、ひずみをｘ軸、応力をｙ軸とするグラフにおいてｘ軸に平行な２つの直線の内側を、式（５－２）は、該グラフにおいて斜めに伸びる２つの直線の内側を表しており、式（ｂ５－１）と式（ｂ５－２）を同時に満たす圧縮ひずみ値ｘＢと圧縮応力値ｙＢは、これらの直線に囲まれる領域（領域（ｂ５））に存在することになる。そのため、「式（ｂ５－１）および式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」とは、圧縮試験によって得られる圧縮ひずみ値ｘＢと圧縮応力値ｙＢの組合せの中で、少なくとも一組がこの領域（ｂ５）内に属している層であるといえる。また、圧縮試験の具体的な測定値として、領域（ｂ５）内に属する組合せがなかったとしても、圧縮ひずみ値ｘＢと圧縮応力値ｙＢの近似曲線を結んだ場合に、その近似曲線が領域（ｂ５）内を通過する場合も、領域（ｂ５）内に属する層であるとみなすことができる。すなわち、「式（ｂ５－１）および式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層」とは、圧縮試験によって得られるいわゆる「応力－ひずみ曲線（Ｓ－Ｓカーブ）」が、領域（ｂ５）を通過する層であるといえる。 In addition, in a graph with strain on the x-axis and stress on the y-axis, formula (b5-1) represents the inside of two straight lines parallel to the x-axis, and formula (5-2) represents the inside of two straight lines extending diagonally in the graph, and the compressive strain value xB and compressive stress value yB that simultaneously satisfy formula (b5-1) and formula (b5-2) are present in the region surrounded by these straight lines (region (b5)). Therefore, "a layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formula (b5-1) and formula (b5-2) can occur" can be said to be a layer in which at least one combination of compressive strain value xB and compressive stress value yB obtained by a compression test belongs to this region (b5). Furthermore, even if there is no combination of specific measured values in the compression test that falls within region (b5), if an approximation curve of compressive strain value xB and compressive stress value yB passes through region (b5), the layer can be considered to belong to region (b5). In other words, a "layer in which a compressed state of compressive strain value xB [%] and compressive stress value yB [MPa] that satisfy formulas (b5-1) and (b5-2) can occur" can be said to be a layer in which the so-called "stress-strain curve (S-S curve)" obtained by the compression test passes through region (b5).
　なお、式（ｂ５－２）の左辺「０．１２９ｘＢ－９．５７５」は、圧縮ひずみ値が「７５％」で圧縮応力値が「０．１０ＭＰａ」となる点と、圧縮ひずみ値が「８５％」で圧縮応力値が「１．３９ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２９」と切片の「－９．５７５」が算出される。したがって、圧縮ひずみ値は「％」単位の数値を、圧縮応力値は「ＭＰａ」単位の数値を利用するものとする。一方、式（ｂ５－２）の右辺「０．１３ｘＢ－１．１９」は、圧縮ひずみ値が「１０％」で圧縮応力値が「０．１０ＭＰａ」となる点と、圧縮ひずみ値が「２０％」で圧縮応力値が「１．３９ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２９」と切片の「－１．１９」が算出される。 The left side of formula (b5-2), "0.129x B -9.575", represents a line connecting the point where the compressive strain value is "75%" and the compressive stress value is "0.10 MPa" and the point where the compressive strain value is "85%" and the compressive stress value is "1.39 MPa", and the slope of "0.129" and the intercept of "-9.575" are calculated from these points. Therefore, the compressive strain value is expressed in "%", and the compressive stress value is expressed in "MPa". On the other hand, the right-hand side of formula (b5-2), "0.13x B -1.19", represents a straight line connecting the point where the compressive strain value is "10%" and the compressive stress value is "0.10 MPa" and the point where the compressive strain value is "20%" and the compressive stress value is "1.39 MPa". From these points, the slope of "0.129" and the intercept of "-1.19" are calculated.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ６－１）および下記式（ｂ６－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。
　式（ｂ６－１）：０．２０≦ｙＢ≦１．１０
　式（ｂ６－２）：０．１２ｘＢ－８．８０≦ｙＢ≦０．０３６ｘＢ－０．３４
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 The buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b6-1) and (b6-2) when the above-mentioned compression test is carried out.
Formula (b6-1): 0.20≦y B ≦1.10
Formula (b6-2): 0.12x B -8.80≦y B ≦0.036x B -0.34
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ６－２）の左辺「０．１２ｘＢ－８．８０」は、圧縮ひずみ値が「７５％」で圧縮応力値が「０．２０ＭＰａ」となる点と、圧縮ひずみ値が「８５％」で圧縮応力値が「１．３９ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２」と切片の「－８．８０」が算出される。一方、式（ｂ６－２）の右辺「０．０３６ｘＢ－０．３４」は、圧縮ひずみ値が「１５％」で圧縮応力値が「０．２０ＭＰａ」となる点と、圧縮ひずみ値が「４０％」で圧縮応力値が「１．１０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０３６」と切片の「－０．３４」が算出される。 The left side of formula (b6-2) "0.12x B -8.80" represents a straight line connecting the point where the compressive strain value is "75%" and the compressive stress value is "0.20 MPa" and the point where the compressive strain value is "85%" and the compressive stress value is "1.39 MPa", and the slope "0.12" and the intercept "-8.80" are calculated from these points. On the other hand, the right side of formula (b6-2) "0.036x B -0.34" represents a straight line connecting the point where the compressive strain value is "15%" and the compressive stress value is "0.20 MPa" and the point where the compressive strain value is "40%" and the compressive stress value is "1.10 MPa", and the slope "0.036" and the intercept "-0.34" are calculated from these points.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ７－１）および下記式（ｂ７－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。
　式（ｂ７－１）：０．３０≦ｙＢ≦０．９０
　式（ｂ７－２）：０．１２ｘＢ－８．７０≦ｙＢ≦０．０４ｘＢ－０．９０
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 The buffer layer is preferably a layer that can generate a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b7-1) and (b7-2) when the above-mentioned compression test is carried out.
Formula (b7-1): 0.30≦y B ≦0.90
Formula (b7-2): 0.12x B -8.70≦y B ≦0.04x B -0.90
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ７－２）の左辺「０．１２ｘＢ－８．７０」は、圧縮ひずみ値が「７５％」で圧縮応力値が「０．３０ＭＰａ」となる点と、圧縮ひずみ値が「８０％」で圧縮応力値が「０．９０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２」と切片の「－８．７０」が算出される。一方、式（ｂ７－２）の右辺「０．０４ｘＢ－０．９０」は、圧縮ひずみ値が「３０％」で圧縮応力値が「０．３０ＭＰａ」となる点と、圧縮ひずみ値が「４５％」で圧縮応力値が「０．９０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０４」と切片の「－０．９０」が算出される。 The left side of formula (b7-2) "0.12x B -8.70" represents a straight line connecting the point where the compressive strain value is "75%" and the compressive stress value is "0.30 MPa" and the point where the compressive strain value is "80%" and the compressive stress value is "0.90 MPa", and the slope "0.12" and the intercept "-8.70" are calculated from these points. On the other hand, the right side of formula (b7-2) "0.04x B -0.90" represents a straight line connecting the point where the compressive strain value is "30%" and the compressive stress value is "0.30 MPa" and the point where the compressive strain value is "45%" and the compressive stress value is "0.90 MPa", and the slope "0.04" and the intercept "-0.90" are calculated from these points.
　緩衝層は、前述の圧縮試験を行ったときに、下記式（ｂ８－１）および下記式（ｂ８－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。
　式（ｂ８－１）：０．４０≦ｙＢ≦０．８０
　式（ｂ８－２）：０．０８ｘＢ－５．６０≦ｙＢ≦０．０３２ｘＢ－０．８８
　緩衝層が上記圧縮状態の生じうる層であると、より好適な緩衝性を確保しやすくなる。 It is more preferable that the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulae (b8-1) and (b8-2) when the above-mentioned compression test is carried out.
Formula (b8-1): 0.40≦y B ≦0.80
Formula (b8-2): 0.08x B -5.60≦y B ≦0.032x B -0.88
When the buffer layer is a layer in which the above-mentioned compressed state can occur, more suitable buffer properties can be easily ensured.
　なお、式（ｂ８－２）の左辺「０．０８ｘＢ－５．６０≦」は、圧縮ひずみ値が「７５％」で圧縮応力値が「０．４０ＭＰａ」となる点と、圧縮ひずみ値が「８０％」で圧縮応力値が「０．８０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０８」と切片の「－５．６０」が算出される。一方、式（ｂ８－２）の右辺「０．０３２ｘＢ－０．８８」は、圧縮ひずみ値が「４０％」で圧縮応力値が「０．４０ＭＰａ」となる点と、圧縮ひずみ値が「５２．５％」で圧縮応力値が「０．８０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０３２」と切片の「－０．８８」が算出される。 The left side of formula (b8-2) "0.08x B -5.60≦" represents a straight line connecting the point where the compressive strain value is "75%" and the compressive stress value is "0.40 MPa" and the point where the compressive strain value is "80%" and the compressive stress value is "0.80 MPa", and the slope "0.08" and the intercept "-5.60" are calculated from these points. On the other hand, the right side of formula (b8-2) "0.032x B -0.88" represents a straight line connecting the point where the compressive strain value is "40%" and the compressive stress value is "0.40 MPa" and the point where the compressive strain value is "52.5%" and the compressive stress value is "0.80 MPa", and the slope "0.032" and the intercept "-0.88" are calculated from these points.
　なお、緩衝層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を低圧縮ひずみ－高圧縮応力側に移動させるためには、例えば緩衝層が繊維成形体である場合、緩衝層の密度を高めることが考えられる。一方、緩衝層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を高圧縮ひずみ－低圧縮応力側に移動させるためには、例えば緩衝層が繊維成形体である場合、緩衝層の密度を低減させることが考えられる。 In order to shift the stress-strain curve (S-S curve) of the buffer layer to the low compressive strain-high compressive stress side, for example when the buffer layer is a fiber molded body, it is possible to increase the density of the buffer layer. On the other hand, in order to shift the stress-strain curve (S-S curve) of the buffer layer to the high compressive strain-low compressive stress side, for example when the buffer layer is a fiber molded body, it is possible to reduce the density of the buffer layer.
　なお、緩衝層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を低圧縮ひずみ－高圧縮応力側に移動させるためには、例えば緩衝層が繊維成形体である場合、緩衝層の密度を高めることが考えられる。一方、緩衝層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を高圧縮ひずみ－低圧縮応力側に移動させるためには、例えば緩衝層が繊維成形体である場合、緩衝層の密度を低減させることが考えられる。 In order to shift the stress-strain curve (S-S curve) of the buffer layer to the low compressive strain-high compressive stress side, for example when the buffer layer is a fiber molded body, it is possible to increase the density of the buffer layer. On the other hand, in order to shift the stress-strain curve (S-S curve) of the buffer layer to the high compressive strain-low compressive stress side, for example when the buffer layer is a fiber molded body, it is possible to reduce the density of the buffer layer.
　上記圧縮試験により得られる応力－ひずみ曲線が、式（ｂ１－１）と式（ｂ１－２）によって囲まれた領域（領域（ｂ１））、好ましくは式（ｂ２－１）と式（ｂ２－２）によって囲まれた領域（領域（ｂ２））、より好ましくは式（ｂ３－１）と式（ｂ３－２）によって囲まれた領域（領域（ｂ３））、さらに好ましくは式（ｂ４－１）と式（ｂ４－２）によって囲まれた領域（領域（ｂ４））を通過する緩衝層は、無機粒子を含んでなる断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい傾向にある。また、上記圧縮試験により得られる応力－ひずみ曲線が、式（ｂ５－１）と式（ｂ５－２）によって囲まれた領域（領域（ｂ５））、好ましくは式（ｂ６－１）と式（ｂ６－２）によって囲まれた領域（領域（ｂ６））、より好ましくは式（ｂ７－１）と式（ｂ７－２）によって囲まれた領域（領域（ｂ７））、さらに好ましくは式（ｂ８－１）と式（ｂ８－２）によって囲まれた領域（領域（ｂ８））を通過する緩衝層は、無機粒子を含んでなる断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する低圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい傾向にある。 A buffer layer in which the stress-strain curve obtained by the above compression test passes through the region surrounded by formulas (b1-1) and (b1-2) (region (b1)), preferably the region surrounded by formulas (b2-1) and (b2-2) (region (b2)), more preferably the region surrounded by formulas (b3-1) and (b3-2) (region (b3)), and even more preferably the region surrounded by formulas (b4-1) and (b4-2) (region (b4)), tends to realize an insulating material with good insulating properties and cushioning properties (for example, good compression characteristics in a loading-unloading test under high pressure conditions described below) when combined with an insulating layer containing inorganic particles. In addition, the stress-strain curve obtained by the compression test passes through the region surrounded by formula (b5-1) and formula (b5-2) (region (b5)), preferably the region surrounded by formula (b6-1) and formula (b6-2) (region (b6)), more preferably the region surrounded by formula (b7-1) and formula (b7-2) (region (b7)), and even more preferably the region surrounded by formula (b8-1) and formula (b8-2) (region (b8)). In combination with a heat insulating layer containing inorganic particles, the buffer layer tends to realize a heat insulating material with good heat insulating properties and cushioning properties (for example, good compression properties in a loading-unloading test under low pressure conditions, which will be described later).
　断熱層は、無機粒子を含んでなるものであれば、その他については特に限定されない。この明細書により開示される断熱材のいくつかの態様において、該断熱材における断熱層は、該断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ１－１）および下記式（ａ１－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。すなわち、上記圧縮試験により得られる応力－ひずみ曲線が、式（ａ１－１）と式（ａ１－２）によって囲まれた領域（領域（ａ１））を通過することが好ましい。
　式（ａ１－１）：０．５０≦ｙＡ≦３．４５
　式（ａ１－２）：０．１２ｘＡ－２．４５≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。断熱層は、硬質、すなわち低圧縮ひずみ－高圧縮応力側であるほど、良好な断熱性を確保しやすくなる傾向がある。そのため、前述の緩衝層で十分な緩衝性を確保することにより、断熱性の確保により特化した断熱層を採用することが可能となり、結果として好適な断熱性と緩衝性をそなえた断熱材となるのである。 The heat insulating layer is not particularly limited as long as it contains inorganic particles. In some embodiments of the heat insulating material disclosed in this specification, the heat insulating layer in the heat insulating material is preferably a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a1-1) and formula (a1-2) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min. That is, it is preferable that the stress-strain curve obtained by the compression test passes through the region surrounded by formula (a1-1) and formula (a1-2) (region (a1)).
Formula (a1-1): 0.50≦y A ≦3.45
Formula (a1-2): 0.12x A -2.45≦y A
If the insulating layer is a layer in which the above-mentioned compression state can occur, better insulating properties can be ensured. The harder the insulating layer is, that is, the lower the compressive strain and the higher the compressive stress, the easier it tends to be to ensure good insulating properties. Therefore, by ensuring sufficient cushioning properties with the aforementioned buffer layer, it becomes possible to employ an insulating layer that is more specialized for ensuring insulating properties, resulting in an insulating material with suitable insulating properties and cushioning properties.
　なお、式（ａ１－２）の左辺「０．１２ｘＡ－２．４５」は、圧縮ひずみ値が「２５％」で圧縮応力値が「０．５０ＭＰａ」となる点と、圧縮ひずみ値が「５０％」で圧縮応力値が「３．４５ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２」と切片の「－２．４５」が算出される。 The left side of formula (a1-2), "0.12x A -2.45", represents a line connecting the point where the compressive strain value is "25%" and the compressive stress value is "0.50 MPa" and the point where the compressive strain value is "50%" and the compressive stress value is "3.45 MPa". From these points, the slope of "0.12" and the intercept of "-2.45" are calculated.
　断熱層は、前述の圧縮試験を行ったときに、下記式（ａ２－１）および下記式（ａ２－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。
　式（ａ２－１）：１．００≦ｙＡ≦３．００
　式（ａ２－２）：０．２０ｘＡ－３．００≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。 It is more preferable that the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a2-1) and (a2-2) when the above-mentioned compression test is carried out.
Formula (a2-1): 1.00≦y A ≦3.00
Formula (a2-2): 0.20xA -3.00≦ yA
When the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
　なお、式（ａ２－２）の左辺「０．２０ｘＡ－３．００」は、圧縮ひずみ値が「２０％」で圧縮応力値が「１．００ＭＰａ」となる点と、圧縮ひずみ値が「３０％」で圧縮応力値が「３．００ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．２０」と切片の「－３．００」が算出される。 The left side of formula (a2-2), "0.20x A -3.00", represents a line connecting the point where the compressive strain value is "20%" and the compressive stress value is "1.00 MPa" and the point where the compressive strain value is "30%" and the compressive stress value is "3.00 MPa". From these points, the slope of "0.20" and the intercept of "-3.00" are calculated.
　断熱層は、前述の圧縮試験を行ったときに、下記式（ａ３－１）および下記式（ａ３－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがさらに好ましい。
　式（ａ３－１）：１．５０≦ｙＡ≦２．５０
　式（ａ３－２）：０．２０ｘＡ－１．５０≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。 It is more preferable that the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a3-1) and (a3-2) when the above-mentioned compression test is carried out.
Formula (a3-1): 1.50≦y A ≦2.50
Formula (a3-2): 0.20xA -1.50≦ yA
When the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
　なお、式（ａ３－２）の左辺「０．２０ｘＡ－１．５０」は、圧縮ひずみ値が「１５％」で圧縮応力値が「１．５０ＭＰａ」となる点と、圧縮ひずみ値が「２０％」で圧縮応力値が「２．５０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．２０」と切片の「－１．５０」が算出される。 The left side of formula (a3-2), "0.20x A -1.50", represents a line connecting the point where the compressive strain value is "15%" and the compressive stress value is "1.50 MPa" and the point where the compressive strain value is "20%" and the compressive stress value is "2.50 MPa". From these points, the slope of "0.20" and the intercept of "-1.50" are calculated.
　また、この明細書により開示される断熱材の他のいくつかの態様において、該断熱材における断熱層は、該断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ４－１）および下記式（ａ４－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることが好ましい。
　式（ａ４－１）：０．１０≦ｙＡ≦１．３９
　式（ａ４－２）：０．０４３ｘＡ－０．５４５≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。断熱層は、硬質、すなわち低圧縮ひずみ－高圧縮応力側であるほど、良好な断熱性を確保しやすくなる傾向がある。そのため、前述の緩衝層で十分な緩衝性を確保することにより、断熱性の確保により特化した断熱層を採用することが可能となり、結果として好適な断熱性と緩衝性をそなえた断熱材となるのである。 In some other embodiments of the thermal insulation material disclosed in this specification, the thermal insulation layer in the thermal insulation material is preferably a layer that can produce a compressed state with a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulas (a4-1) and (a4-2) when a compression test is performed on only the thermal insulation layer at a compression speed of 0.5 mm/min.
Formula (a4-1): 0.10≦y A ≦1.39
Formula (a4-2): 0.043x A -0.545≦y A
If the insulating layer is a layer in which the above-mentioned compression state can occur, better insulating properties can be ensured. The harder the insulating layer is, that is, the lower the compressive strain and the higher the compressive stress, the easier it tends to be to ensure good insulating properties. Therefore, by ensuring sufficient cushioning properties with the aforementioned buffer layer, it becomes possible to employ an insulating layer that is more specialized for ensuring insulating properties, resulting in an insulating material with suitable insulating properties and cushioning properties.
　なお、式（ａ４－２）の左辺「０．０４３ｘＡ－０．５４５」は、圧縮ひずみ値が「１５％」で圧縮応力値が「０．１０ＭＰａ」となる点と、圧縮ひずみ値が「４５％」で圧縮応力値が「１．３９ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０４３」と切片の「－０．５４５」が算出される。 The left side of formula (a4-2), "0.043x A -0.545", represents a line connecting the point where the compressive strain value is "15%" and the compressive stress value is "0.10 MPa" and the point where the compressive strain value is "45%" and the compressive stress value is "1.39 MPa". From these points, the slope of "0.043" and the intercept of "-0.545" are calculated.
　断熱層は、前述の圧縮試験を行ったときに、下記式（ａ５－１）および下記式（ａ５－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがより好ましい。
　式（ａ５－１）：０．２０≦ｙＡ≦１．１０
　式（ａ５－２）：０．０９ｘＡ－１．１５≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。 It is more preferable that the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a5-1) and (a5-2) when the above-mentioned compression test is carried out.
Formula (a5-1): 0.20≦y A ≦1.10
Formula (a5-2): 0.09x A −1.15≦y A
When the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
　なお、式（ａ５－２）の左辺「０．０９ｘＡ－１．１５」は、圧縮ひずみ値が「１５％」で圧縮応力値が「０．２０ＭＰａ」となる点と、圧縮ひずみ値が「２５％」で圧縮応力値が「１．１０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．０９」と切片の「－１．１５」が算出される。 The left side of formula (a5-2), "0.09x A -1.15", represents a line connecting the point where the compressive strain value is "15%" and the compressive stress value is "0.20 MPa" and the point where the compressive strain value is "25%" and the compressive stress value is "1.10 MPa". From these points, the slope of "0.09" and the intercept of "-1.15" are calculated.
　断熱層は、前述の圧縮試験を行ったときに、下記式（ａ６－１）および下記式（ａ６－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層であることがさらに好ましい。
　式（ａ６－１）：０．３０≦ｙＡ≦０．９０
　式（ａ６－２）：０．１２ｘＡ－０．９０≦ｙＡ
　断熱層が上記圧縮状態の生じうる層であると、より良好な断熱性を確保しやすくなる。 It is more preferable that the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a6-1) and (a6-2) when the above-mentioned compression test is carried out.
Formula (a6-1): 0.30≦y A ≦0.90
Formula (a6-2): 0.12x A -0.90 ≦ y A
When the heat insulating layer is a layer in which the above-mentioned compressed state can occur, better heat insulating properties can be easily ensured.
　なお、式（ａ６－２）の左辺「０．１２ｘＡ－０．９０」は、圧縮ひずみ値が「１０％」で圧縮応力値が「０．３０ＭＰａ」となる点と、圧縮ひずみ値が「１５％」で圧縮応力値が「０．９０ＭＰａ」となる点を結んだ直線を表しており、これらの点から、傾きの「０．１２」と切片の「－０．９０」が算出される。 The left side of formula (a6-2), "0.12x A -0.90", represents a line connecting the point where the compressive strain value is "10%" and the compressive stress value is "0.30 MPa" and the point where the compressive strain value is "15%" and the compressive stress value is "0.90 MPa". From these points, the slope of "0.12" and the intercept of "-0.90" are calculated.
　なお、断熱層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を低圧縮ひずみ－高圧縮応力側に移動させるためには、例えば断熱層が無機粒子および無機繊維を含む混合物を成形した成形体である場合、断熱層の密度を高めることが考えられる。一方、断熱層の応力－ひずみ曲線（Ｓ－Ｓカーブ）を高圧縮ひずみ－低圧縮応力側に移動させるためには、例えば断熱層が無機粒子および無機繊維を含む混合物を成形した成形体である場合、断熱層の密度を低減させることが考えられる。 In order to shift the stress-strain curve (S-S curve) of the insulating layer towards the low compressive strain - high compressive stress side, for example when the insulating layer is a molded body made from a mixture containing inorganic particles and inorganic fibers, it is possible to increase the density of the insulating layer. On the other hand, in order to shift the stress-strain curve (S-S curve) of the insulating layer towards the high compressive strain - low compressive stress side, for example when the insulating layer is a molded body made from a mixture containing inorganic particles and inorganic fibers, it is possible to reduce the density of the insulating layer.
　上記圧縮試験により得られる応力－ひずみ曲線が、式（ａ１－１）と式（ａ１－２）によって囲まれた領域（領域（ａ１））、好ましくは式（ａ２－１）と式（ａ２－２）によって囲まれた領域（領域（ａ２））、より好ましくは式（ａ３－１）と式（ａ３－２）によって囲まれた領域（領域（ａ３））を通過する断熱層は、上記応力－ひずみ曲線が領域（ｂ１）（好ましくは領域（ｂ２）、より好ましくは領域（ｂ３）、さらに好ましくは領域（ｂ４））を通過する緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい傾向にある。また、上記圧縮試験により得られる応力－ひずみ曲線が、式（ａ４－１）と式（ａ４－２）によって囲まれた領域（領域（ａ４））、好ましくは式（ａ５－１）と式（ａ５－２）によって囲まれた領域（領域（ａ５））、より好ましくは式（ａ６－１）と式（ａ６－２）によって囲まれた領域（領域（ａ６））を通過する断熱層は、上記応力－ひずみ曲線が領域（ｂ５）（好ましくは領域（ｂ６）、より好ましくは領域（ｂ７）、さらに好ましくは領域（ｂ８））を通過する緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する低圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい傾向にある。 An insulating layer, in which the stress-strain curve obtained by the above compression test passes through the region enclosed by formulas (a1-1) and (a1-2) (region (a1)), preferably the region enclosed by formulas (a2-1) and (a2-2) (region (a2)), and more preferably the region enclosed by formulas (a3-1) and (a3-2) (region (a3)), tends to easily realize an insulating material with good insulating properties and cushioning properties (for example, good compression characteristics in a loading-unloading test under high pressure conditions described below) when combined with a buffer layer, in which the above stress-strain curve passes through region (b1) (preferably region (b2), more preferably region (b3), and even more preferably region (b4)). In addition, a thermal insulation layer in which the stress-strain curve obtained by the compression test passes through the region surrounded by formulas (a4-1) and (a4-2) (region (a4)), preferably the region surrounded by formulas (a5-1) and (a5-2) (region (a5)), and more preferably the region surrounded by formulas (a6-1) and (a6-2) (region (a6)), tends to realize a thermal insulation material with good thermal insulation and cushioning properties (for example, good compression characteristics in a loading-unloading test under low pressure conditions, which will be described later) when combined with a buffer layer in which the stress-strain curve passes through region (b5) (preferably region (b6), more preferably region (b7), and even more preferably region (b8)).
　以下、「断熱層」、「緩衝層」等について詳細に説明する。 The "insulating layer" and "buffer layer" are explained in detail below.
（断熱層）
　断熱層は、無機粒子を含んでなる層である。ここで「無機粒子を含んでなる層」とは、構成材料として少なくとも無機粒子を含み、層状に形成されたものであることを意味する。無機粒子の種類は、特に限定されず、例えば二酸化ケイ素粒子（シリカ）、酸化チタン粒子、酸化亜鉛粒子、酸化アルミニウム粒子、炭化ケイ素粒子、チタン鉄鉱粒子（イルメナイト、ＦｅＴｉＯ）、ケイ酸ジルコニウム粒子、酸化鉄（III）粒子、鉄（II）（ウスタイト（ＦｅＯ）粒子、マグネタイト粒子（Ｆｅ３Ｏ４）、ヘマタイト粒子（Ｆｅ２Ｏ３））、二酸化クロム粒子、酸化ジルコニウム粒子、二酸化マンガン粒子、ジルコニアゾル、チタニアゾル、シリカゾル、アルミナゾル、ベントナイト粒子、およびカオリン粒子等が挙げられる。無機粒子の他の例として、黒鉛（グラファイト）、カーボンブラック、カーボン等の炭素系粒子が挙げられる。黒鉛としては、粒子径１８μｍ以下のものが好ましい。黒鉛の形状は、鱗片状、鱗状、球状、等方性（人造）、異方性（人造）などいずれも使用できる。鱗片状黒鉛としては、例えば、ＢＦ－３ＡＫ、ＦＢＦ、ＢＦ－１０ＡＫ（中越黒鉛工業所社製）、ＧＥ－１、Ｚ－５Ｆ、ＣＮＰ７、Ｖ－１０Ｆ（伊藤黒鉛工業社製）、鱗状黒鉛としては、ＨＬＰ、ＳＢ－１（中越黒鉛工業所社製）、球状黒鉛としては、ＳＧ－ＢＨ８（伊藤黒鉛工業社製）、等方性黒鉛（人造）としては、例えばＡＧＢ－５（伊藤黒鉛工業社製）、異方性黒鉛（人造）としては、例えばＡＧ－６Ｔ（伊藤黒鉛工業社製）などが挙げられる。カーボンブラックとしては、例えば、ＴＯＫＡＢＬＡＣＫ ＃５５００（東海カーボン社製）、三菱カーボンブラックＭＡ１００（三菱ケミカル社製）などが挙げられる。断熱層は、１種類の無機粒子を含んでいてもよいし、２種類以上の無機粒子を含んでいてもよい。無機粒子は、熱輻射を抑制できる、より具体的には赤外線領域に吸収ピークを有する無機粒子であることが好ましい。赤外線領域の吸収ピークは、赤外分光光度計によって測定できる。また、無機粒子は、無機繊維同士を結着させるバインダーとして機能してもよい。 (Thermal insulation layer)
The heat insulating layer is a layer containing inorganic particles. Here, "a layer containing inorganic particles" means that it contains at least inorganic particles as a constituent material and is formed in a layer shape. The type of inorganic particles is not particularly limited, and examples thereof include silicon dioxide particles (silica), titanium oxide particles, zinc oxide particles, aluminum oxide particles, silicon carbide particles, ilmenite particles (ilmenite, FeTiO), zirconium silicate particles, iron (III) oxide particles, iron (II) (wustite (FeO) particles, magnetite particles (Fe 3 O 4 ), hematite particles (Fe 2 O 3 )), chromium dioxide particles, zirconium oxide particles, manganese dioxide particles, zirconia sol, titania sol, silica sol, alumina sol, bentonite particles, and kaolin particles. Other examples of inorganic particles include carbon-based particles such as graphite, carbon black, and carbon. As graphite, those with a particle diameter of 18 μm or less are preferable. The shape of graphite may be any of flake, scaly, spherical, isotropic (artificial), anisotropic (artificial), etc. Examples of flake graphite include BF-3AK, FBF, BF-10AK (manufactured by Chuetsu Graphite Industries Co., Ltd.), GE-1, Z-5F, CNP7, and V-10F (manufactured by Ito Graphite Industries Co., Ltd.), examples of scaly graphite include HLP and SB-1 (manufactured by Chuetsu Graphite Industries Co., Ltd.), examples of spherical graphite include SG-BH8 (manufactured by Ito Graphite Industries Co., Ltd.), examples of isotropic graphite (artificial) include AGB-5 (manufactured by Ito Graphite Industries Co., Ltd.), and examples of anisotropic graphite (artificial) include AG-6T (manufactured by Ito Graphite Industries Co., Ltd.). Examples of carbon black include TOKABLACK #5500 (manufactured by Tokai Carbon Co., Ltd.), Mitsubishi Carbon Black MA100 (manufactured by Mitsubishi Chemical Corporation), etc. The heat insulating layer may contain one type of inorganic particles or may contain two or more types of inorganic particles. The inorganic particles are preferably inorganic particles that can suppress thermal radiation, more specifically, have an absorption peak in the infrared region. The absorption peak in the infrared region can be measured by an infrared spectrophotometer. The inorganic particles may also function as a binder that binds inorganic fibers together.
　断熱層における無機粒子の含有量は、特に限定されず、例えば該断熱層の５０質量％～９９．５質量％であり、好ましくは６０質量％以上、より好ましくは７０質量％以上、さらに好ましくは８０質量％以上であり、好ましくは９５質量％以下、より好ましくは９０質量％以下、さらに好ましくは８５質量％以下である。無機粒子の含有量が上記範囲内であると、良好な断熱性と機械強度を確保しやすくなる。 The content of inorganic particles in the heat insulating layer is not particularly limited, and is, for example, 50% to 99.5% by mass of the heat insulating layer, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less. When the content of inorganic particles is within the above range, it becomes easier to ensure good heat insulating properties and mechanical strength.
　断熱層は、無機粒子として二酸化ケイ素（シリカ、ＳｉＯ２）を含むことが好ましい。二酸化ケイ素粒子は、構造的特徴として結晶質シリカ、非晶質シリカ等に分類することができ、入手方法によって天然シリカ、合成シリカ等に分類することができる。また、合成シリカの中でも、製造方法によって乾式シリカ、湿式シリカ、シリカエアロゲル等に分類することができ、さらに乾式シリカの中でも、燃焼法によって得られるシリカ、アーク法によって得られるシリカ等に、湿式シリカの中でも、ゲル法によって得られるシリカ、沈降法によって得られるシリカ等に分類することができる。二酸化ケイ素粒子の種類は、特に限定されないが、乾式シリカ、シリカエアロゲルが好ましく、さらに乾式シリカの１種としてフュームドシリカがより好ましく、フュームドシリカの中でも、親水性フュームドシリカが特に好ましい。上記親水性フュームドシリカ（Ｆｕｍｅｄ　Ｓｉｌｉｃａ）とは、表面に親水性のシラノール基（Ｓｉ－ＯＨ）を主に有するフュームドシリカを表し、一般的には表面処理等によってシラノール基が疎水性基に置換されていないフュームドシリカを表す。
　なお、二酸化ケイ素粒子は、一般的に、一次粒子が凝集した凝集体として存在したり、凝集体がさらに凝集して集魂粒子として存在したりすることがある。ここに開示される断熱層における二酸化ケイ素粒子は、一次粒子の状態で分散していてもよく、凝集体の状態で分散していてもよく、集魂粒子の状態で分散していてもよく、またこれらの組合せとして分散していてもよい。 The heat insulating layer preferably contains silicon dioxide (silica, SiO 2 ) as inorganic particles. Silicon dioxide particles can be classified into crystalline silica, amorphous silica, etc. according to structural characteristics, and can be classified into natural silica, synthetic silica, etc. according to the method of acquisition. Synthetic silica can be classified into dry silica, wet silica, silica aerogel, etc. according to the manufacturing method, and dry silica can be further classified into silica obtained by a combustion method, silica obtained by an arc method, etc., and wet silica can be classified into silica obtained by a gel method, silica obtained by a precipitation method, etc. The type of silicon dioxide particles is not particularly limited, but dry silica and silica aerogel are preferred, and fumed silica is more preferred as a type of dry silica, and hydrophilic fumed silica is particularly preferred among fumed silica. The hydrophilic fumed silica (Fumed Silica) refers to fumed silica that mainly has hydrophilic silanol groups (Si-OH) on the surface, and generally refers to fumed silica in which the silanol groups have not been substituted with hydrophobic groups by surface treatment or the like.
In addition, silicon dioxide particles generally exist as aggregates of primary particles, or aggregates further aggregate to form aggregated particles. The silicon dioxide particles in the heat insulating layer disclosed herein may be dispersed in the form of primary particles, aggregates, aggregated particles, or a combination thereof.
　二酸化ケイ素粒子の平均一次粒子径は、特に限定されず、例えば１ｎｍ～１００ｎｍであり、好ましくは２ｎｍ以上、より好ましくは４ｎｍ以上であり、好ましくは８０ｎｍ以下、より好ましくは４０ｎｍ以下、さらに好ましくは３０ｎｍ以下、特に好ましくは２０ｎｍ以下である。二酸化ケイ素粒子がフュームドシリカである場合の平均一次粒子径は、例えば１ｎｍ～４０ｎｍであり、好ましくは２ｎｍ以上、より好ましくは４ｎｍ以上であり、好ましくは３０ｎｍ以下、より好ましくは２０ｎｍ以下、さらに好ましくは１８ｎｍ以下である。二酸化ケイ素粒子がシリカエアロゲルの場合の平均一次粒子径は、例えば１ｎｍ～２０ｎｍであり、好ましくは１８ｎｍ以下、より好ましくは１０ｎｍ以下である。二酸化ケイ素粒子の平均一次粒子径が上記範囲内であると、良好な断熱性を確保しやすくなる。なお、二酸化ケイ素粒子の平均一次粒子径を把握する方法としては、走査型電子顕微鏡（ＳＥＭ）や透過型電子顕微鏡（ＴＥＭ）等の電子顕微鏡を用いて測定する方法が挙げられる。具体的には、電子顕微鏡に映る二酸化ケイ素粒子をランダムに選択して粒子径を測定し、その数値の平均値を算出する方法が挙げられる。粒子径としては、粒子が球状である場合にはその直径を、粒子が楕円形である場合にはその短径と長径との中間値を、不定形粒子である場合にはその短辺と長辺との中間値を採用することが挙げられる。 The average primary particle diameter of the silicon dioxide particles is not particularly limited, and is, for example, 1 nm to 100 nm, preferably 2 nm or more, more preferably 4 nm or more, preferably 80 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, and particularly preferably 20 nm or less. When the silicon dioxide particles are fumed silica, the average primary particle diameter is, for example, 1 nm to 40 nm, preferably 2 nm or more, more preferably 4 nm or more, preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 18 nm or less. When the silicon dioxide particles are silica aerogel, the average primary particle diameter is, for example, 1 nm to 20 nm, preferably 18 nm or less, and more preferably 10 nm or less. When the average primary particle diameter of the silicon dioxide particles is within the above range, good thermal insulation is easily ensured. In addition, as a method for determining the average primary particle diameter of the silicon dioxide particles, a method of measuring using an electron microscope such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM) can be mentioned. Specifically, one method is to randomly select silicon dioxide particles seen under an electron microscope, measure their particle diameter, and calculate the average value. The particle diameter can be calculated by measuring the diameter if the particle is spherical, the midpoint between the short and long axes if the particle is elliptical, or the midpoint between the short and long sides if the particle is irregular.
　二酸化ケイ素粒子の二次凝集体（一次粒子の凝集体）の平均粒子径は、特に限定されず、例えば０．１μｍ～１００μｍであり、好ましくは１μｍ以上、より好ましくは２μｍ以上であり、好ましくは９０μｍ以下、より好ましくは８０μｍ以下である。なお、二酸化ケイ素粒子の二次凝集体の平均粒子径を把握する方法としては、一次粒子径と同様の方法を用いて測定する方法が挙げられる。 The average particle size of secondary agglomerates of silicon dioxide particles (aggregates of primary particles) is not particularly limited, and is, for example, 0.1 μm to 100 μm, preferably 1 μm or more, more preferably 2 μm or more, and preferably 90 μm or less, more preferably 80 μm or less. The average particle size of secondary agglomerates of silicon dioxide particles can be determined by measuring them in the same manner as the primary particle size.
　二酸化ケイ素粒子のＢＥＴ比表面積は、例えば９０ｍ２／ｇ以上３８０ｍ２／ｇ未満であり、好ましくは１３０ｍ２／ｇ以上、より好ましくは１７５ｍ２／ｇ以上、さらに好ましくは２００ｍ２／ｇ以上であり、好ましくは３５０ｍ２／ｇ以下、より好ましくは３２０ｍ２／ｇ以下、さらに好ましくは２００ｍ２／ｇ以下である。二酸化ケイ素粒子のＢＥＴ比表面積が上記範囲内であると、高温高湿条件においても断熱性を確保しやすくなる。なお、ＢＥＴ比表面積は、国際標準化機構ＩＳＯ　５７９４／１に準拠した測定方法により、多点窒素吸着法（ＢＥＴ法）によって測定することができる。また、例えばアエロジル社製「ＡＥＲＯＳＩＬ３８０」は、ＢＥＴ比表面積の公称値が３８０ｍ２／ｇとされており、誤差を考慮すると３５０ｍ２／ｇ～４１０ｍ２／ｇと表記されている。この場合、本明細書においては公称値である３８０ｍ２／ｇを基準として考えるものとする。 The BET specific surface area of the silicon dioxide particles is, for example, 90 m 2 /g or more and less than 380 m 2 /g, preferably 130 m 2 /g or more, more preferably 175 m 2 /g or more, even more preferably 200 m 2 /g or more, and preferably 350 m 2 /g or less, more preferably 320 m 2 /g or less, and even more preferably 200 m 2 /g or less. If the BET specific surface area of the silicon dioxide particles is within the above range, it is easy to ensure heat insulation even under high temperature and high humidity conditions. The BET specific surface area can be measured by a multipoint nitrogen adsorption method (BET method) according to the measurement method of the International Organization for Standardization ISO 5794/1. For example, the nominal value of the BET specific surface area of "AEROSIL380" manufactured by Aerosil Corporation is 380 m 2 /g, and when an error is taken into consideration, the range is expressed as 350 m 2 /g to 410 m 2 /g. In this case, the nominal value of 380 m 2 /g is considered as the standard in this specification.
　二酸化ケイ素粒子の見かけ比重は、特に限定されず、例えば３０ｇ／Ｌ～１３０ｇ／Ｌであり、好ましくは４０ｇ／Ｌ以上、より好ましくは５０ｇ／Ｌ以上であり、好ましくは１００ｇ／Ｌ以下、より好ましくは８０ｇ／Ｌ以下、さらに好ましくは６０ｇ／Ｌ以下である。なお、二酸化ケイ素粒子の見かけ比重を把握する方法としては、二酸化ケイ素粒子を２５０ｍＬメスシリンダー等の容積を測定できる容器に充填し、二酸化ケイ素粒子の充填質量（Ｘｇ）と充填容積（ＹｍＬ）を測定して、充填質量を充填容積で除算（［見かけ比重（ｇ／Ｌ）］＝Ｘ／Ｙ×１０００）した数値とすることが挙げられる。 The apparent specific gravity of the silicon dioxide particles is not particularly limited, and is, for example, 30 g/L to 130 g/L, preferably 40 g/L or more, more preferably 50 g/L or more, and preferably 100 g/L or less, more preferably 80 g/L or less, and even more preferably 60 g/L or less. The apparent specific gravity of the silicon dioxide particles can be determined by filling a container capable of measuring the volume, such as a 250 mL graduated cylinder, measuring the filling mass (X g) and filling volume (Y mL) of the silicon dioxide particles, and dividing the filling mass by the filling volume ([apparent specific gravity (g/L)] = X/Y x 1000).
　二酸化ケイ素粒子の例としては、親水性フュームドシリカであるＡＥＲＯＳＩＬシリーズ（日本アエロジル社製）のＡＥＲＯＳＩＬ５０、９０、１３０、２００、３００、３８０、レオロシールシリーズ（トクヤマ社製）のＱＳ－０９、ＱＳ－１０、ＱＳ－１０２、ＱＳ－２０、ＱＳ－３０、ＱＳ－４０、ＨＤＫシリーズ（旭化成ワッカーシリコン社製）のＨＤＫＶ１５、Ｎ２０、Ｔ３０、Ｔ４０等や、疎水性フュームドシリカであるＡＥＲＯＳＩＬシリーズ（日本アエロジル社製）のＡＥＲＯＳＩＬ Ｒ９７２、Ｒ９７６Ｓ、ＨＤＫシリーズ（旭化成ワッカーシリコン社製）のＨＤＫ Ｈ１５、Ｈ２０、Ｈ３０等が、シリカエアロゲルであるエアリカ（トクヤマ社製）等が挙げられる。なお、断熱層は、１種類の二酸化ケイ素粒子を含んでいてもよいし、２種類以上の二酸化ケイ素粒子を含んでいてもよい。 Examples of silicon dioxide particles include hydrophilic fumed silica such as AEROSIL 50, 90, 130, 200, 300, 380 from the AEROSIL series (manufactured by Nippon Aerosil Co., Ltd.), QS-09, QS-10, QS-102, QS-20, QS-30, QS-40 from the Reolosil series (manufactured by Tokuyama Corporation), HDKV15, N20, T30, T40 from the HDK series (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.), hydrophobic fumed silica such as AEROSIL R972, R976S from the AEROSIL series (manufactured by Nippon Aerosil Co., Ltd.), HDK H15, H20, H30 from the HDK series (manufactured by Wacker Asahi Kasei Silicone Co., Ltd.), and silica aerogel such as Airica (manufactured by Tokuyama Corporation). The heat insulating layer may contain one type of silicon dioxide particles, or may contain two or more types of silicon dioxide particles.
　断熱層における二酸化ケイ素粒子の含有量は、特に限定されず、例えば５０質量％以上（典型的には５０質量％～９９．５質量％）であり、好ましくは６０質量％以上、より好ましくは７０質量％以上、さらに好ましくは８０質量％以上であり、好ましくは９５質量％以下、より好ましくは９０質量％以下、さらに好ましくは８５質量％以下である。二酸化ケイ素粒子の含有量が上記範囲内であると、良好な断熱性と機械強度を確保しやすくなる。 The content of silicon dioxide particles in the insulating layer is not particularly limited, and is, for example, 50% by mass or more (typically 50% by mass to 99.5% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less. When the content of silicon dioxide particles is within the above range, it becomes easier to ensure good insulation properties and mechanical strength.
　断熱層は、前述の無機粒子を含んでなる層であれば、その他の成分を含んでいてもよい。いくつかの態様では、無機繊維を含むことが好ましい。無機繊維の種類は、特に限定されないが、例えばシリカ繊維、ガラス繊維、アルミナ繊維、シリカ－アルミナ繊維、シリカ－アルミナ－マグネシア繊維、生体溶解性無機繊維、ガラス繊維、ジルコニア繊維、ケイ酸アルカリ土類金属塩繊維、アルカリアースシリケート（ＡＥＳ）繊維、グラスウール、ロックウールおよびバサルト繊維等が挙げられる。無機繊維が上記のものであると、耐熱性が向上する。なお、断熱層は、１種類の無機繊維を含んでいてもよいし、２種類以上の無機繊維を含んでいてもよい。 The insulating layer may contain other components as long as it is a layer containing the inorganic particles described above. In some embodiments, it is preferable that the insulating layer contains inorganic fibers. The type of inorganic fiber is not particularly limited, but examples include silica fiber, glass fiber, alumina fiber, silica-alumina fiber, silica-alumina-magnesia fiber, biosoluble inorganic fiber, glass fiber, zirconia fiber, alkaline earth silicate fiber, alkaline earth silicate (AES) fiber, glass wool, rock wool, and basalt fiber. When the inorganic fiber is one of the above, heat resistance is improved. The insulating layer may contain one type of inorganic fiber, or two or more types of inorganic fibers.
　断熱層における無機繊維の含有量は、特に限定されず、例えば０．５質量％～５０質量％であり、好ましくは１質量％以上、より好ましくは３質量％以上、さらに好ましくは５質量％以上であり、好ましくは４０質量％以下、より好ましくは３５質量％以下、さらに好ましくは３０質量％以下である。繊維の含有量が上記範囲内であると、良好な熱抵抗を確保しやすくなるとともに、断熱層を製造しやすくなる。 The content of inorganic fibers in the insulating layer is not particularly limited, and is, for example, 0.5% by mass to 50% by mass, preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less. If the fiber content is within the above range, it becomes easier to ensure good thermal resistance and to manufacture the insulating layer.
　断熱層に含まれる無機繊維の平均繊維長は、特に限定されず、例えば０．０５ｍｍ～５０ｍｍであり、好ましくは０．５ｍｍ以上、より好ましくは１．０ｍｍ以上、さらに好ましくは２ｍｍ以上であり、好ましくは３５ｍｍ以下、より好ましくは３０ｍｍ以下、より好ましくは２５ｍｍ以下、より好ましくは１３ｍｍ以下、さらに好ましくは１０ｍｍ以下であり、８ｍｍ以下でもよく、６ｍｍ以下でもよい。繊維の平均繊維長が上記範囲内であると、断熱層を製造しやすくなる。 The average fiber length of the inorganic fibers contained in the insulating layer is not particularly limited, and is, for example, 0.05 mm to 50 mm, preferably 0.5 mm or more, more preferably 1.0 mm or more, even more preferably 2 mm or more, and preferably 35 mm or less, more preferably 30 mm or less, more preferably 25 mm or less, more preferably 13 mm or less, even more preferably 10 mm or less, and may be 8 mm or less, or 6 mm or less. When the average fiber length of the fibers is within the above range, it is easier to manufacture the insulating layer.
　断熱層に含まれる無機繊維の平均繊維径は、特に限定されず、例えば０．１μｍ～５０μｍであり、好ましくは１μｍ以上、より好ましくは５μｍ以上、さらに好ましくは７μｍ以上であり、好ましくは２５μｍ以下、より好ましくは２０μｍ以下、さらに好ましくは１５μｍ以下である。繊維の平均繊維径が上記範囲内であると、良好な断熱性と機械強度を確保しやすくなる。 The average fiber diameter of the inorganic fibers contained in the thermal insulation layer is not particularly limited, and is, for example, 0.1 μm to 50 μm, preferably 1 μm or more, more preferably 5 μm or more, even more preferably 7 μm or more, and preferably 25 μm or less, more preferably 20 μm or less, even more preferably 15 μm or less. When the average fiber diameter of the fibers is within the above range, it becomes easier to ensure good thermal insulation properties and mechanical strength.
　断熱層は、有機繊維を含んでいてもよい。有機繊維の具体例としては、セルロースファイバー、ポリエステル、ポリプロピレン等からなるフェルト等が挙げられる。有機繊維の使用は、緩衝性の向上や、繰り返し圧力疲労への耐久性の向上等の観点から有利となり得る。断熱層における有機繊維の含有量は、所望の使用効果が得られるように適宜設定することができ、無機繊維１００質量部に対して例えば０質量部超、１質量部以上、４質量以上、８質量部以上または１６質量部以上であり得る。一方、いくつかの態様では、耐熱性等の観点から、断熱層における有機繊維の含有量は、無機繊維１００質量部に対して１００質量部未満であることが適当であり、５０質量部未満であることが有利であり、２０質量部未満であってもよく、１０質量部未満であってもよく、５質量部未満または１質量部未満であってもよく、有機繊維を含まない断熱層であってもよい。 The heat insulating layer may contain organic fibers. Specific examples of organic fibers include cellulose fibers, polyester, felt made of polypropylene, etc. The use of organic fibers can be advantageous in terms of improving cushioning properties and durability against repeated pressure fatigue. The content of organic fibers in the heat insulating layer can be appropriately set so as to obtain the desired usage effect, and may be, for example, more than 0 parts by mass, 1 part by mass or more, 4 parts by mass or more, 8 parts by mass or more, or 16 parts by mass or more, relative to 100 parts by mass of inorganic fibers. On the other hand, in some embodiments, from the viewpoint of heat resistance, etc., the content of organic fibers in the heat insulating layer is suitably less than 100 parts by mass, advantageously less than 50 parts by mass, may be less than 20 parts by mass, may be less than 10 parts by mass, may be less than 5 parts by mass, or may be less than 1 part by mass, or may be an insulation layer that does not contain organic fibers.
　断熱層は、前述の無機粒子に加えて、上記その他の成分としてバインダー（結合剤）を含んでいてもよい。断熱層は、１種類のバインダーを含んでいてもよいし、２種類以上のバインダーを含んでいてもよい。断熱層がバインダーを含むことにより、形状安定性が向上する傾向にある。 The heat insulating layer may contain a binder (binding agent) as one of the other components in addition to the inorganic particles described above. The heat insulating layer may contain one type of binder, or may contain two or more types of binders. When the heat insulating layer contains a binder, shape stability tends to be improved.
　断熱層がバインダーを含む場合のバインダー種類は、特に限定されないが、有機バインダーと無機バインダーに分類することができる。有機バインダーの具体例としては、熱可塑性樹脂、熱可塑性エラストマー、熱硬化性樹脂、熱硬化性エラストマー、糖類、水溶性高分子等が挙げられる。無機バインダーの具体例としては、酸化アルミニウム、酸化ジルコニウム、酸化マグネシウム、酸化チタン、酸化カルシウム等が挙げられる。バインダーが上記のものであると、形状安定性が効果的に向上する。 When the heat insulating layer contains a binder, the type of binder is not particularly limited, but can be classified into organic binders and inorganic binders. Specific examples of organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, water-soluble polymers, etc. Specific examples of inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, calcium oxide, etc. If the binder is one of the above, shape stability is effectively improved.
　断熱層がバインダーを含む場合のバインダーの含有量は、特に限定されず、例えば該断熱層の０．０１質量％～１０質量％であり、好ましくは０．０５質量％以上、より好ましくは０．１質量％以上、さらに好ましくは０．２質量％以上であり、好ましくは５質量％以下、より好ましくは３質量％以下、さらに好ましくは１質量％以下である。バインダーの含有量が上記範囲内であると、断熱性と形状安定性が両立しやすくなる。 When the insulating layer contains a binder, the binder content is not particularly limited, and is, for example, 0.01% to 10% by mass of the insulating layer, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.2% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. When the binder content is within the above range, it becomes easier to achieve both thermal insulation and shape stability.
　断熱層は、前述の無機粒子を含んでなる層であり、なかでも無機粒子および無機繊維を含む混合物を成形した成形体であることが好ましい。無機粒子および無機繊維を含む混合物を成形した成形体であると、断熱性と機械強度の両立を図りやすくなる。断熱層が無機粒子および無機繊維を含む混合物を成形した成形体である場合の無機粒子、無機繊維等の混合方法等の詳細は後述する。 The heat insulating layer is a layer containing the aforementioned inorganic particles, and is preferably a molded body formed from a mixture containing inorganic particles and inorganic fibers. A molded body formed from a mixture containing inorganic particles and inorganic fibers makes it easier to achieve both thermal insulation and mechanical strength. Details of the method of mixing the inorganic particles, inorganic fibers, etc. when the heat insulating layer is a molded body formed from a mixture containing inorganic particles and inorganic fibers will be described later.
　断熱層の厚みは、特に限定されず、例えば０．５ｍｍ～１０ｍｍであり、好ましくは０．７ｍｍ以上であり、より好ましくは０．８ｍｍ以上または０．９ｍｍ以上である。いくつかの態様において、断熱層の厚みは、好ましくは１ｍｍ以上、より好ましくは１．５ｍｍ以上、さらに好ましくは２ｍｍ以上であり、好ましくは７ｍｍ以下、より好ましくは５ｍｍ以下、さらに好ましくは３ｍｍ以下である。断熱層の厚みが上記範囲内であると、良好な断熱性を確保しやすくなるとともに、断熱材の大型化を抑制することができる。いくつかの態様において、断熱層の厚みは、２ｍｍ未満であってもよく、１．５ｍｍ未満であってもよく、１．３ｍｍ以下であってもよく、１ｍｍ以下または１ｍｍ未満であってもよい。断熱層の厚みを小さくすることにより、断熱材の薄型化や軽量化を図ることができる。なお、断熱層の厚みとしては、断熱層の断面を厚さ測定器（例えば、尾崎製作所製のデジタルシックネスゲージＪＡＮ－２５７（測定子Φ２０ｍｍ））で数箇所（例えば、１０か所）測定した数値の平均値を採用することができる。 The thickness of the insulating layer is not particularly limited, and is, for example, 0.5 mm to 10 mm, preferably 0.7 mm or more, more preferably 0.8 mm or more or 0.9 mm or more. In some embodiments, the thickness of the insulating layer is preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. When the thickness of the insulating layer is within the above range, good insulation properties can be easily ensured and the size of the insulating material can be suppressed. In some embodiments, the thickness of the insulating layer may be less than 2 mm, less than 1.5 mm, 1.3 mm or less, or 1 mm or less. By reducing the thickness of the insulating layer, the insulating material can be made thinner and lighter. The thickness of the insulating layer can be the average value of the values measured at several points (for example, 10 points) on the cross section of the insulating layer with a thickness gauge (for example, Ozaki Manufacturing's digital thickness gauge JAN-257 (measuring probe Φ20 mm)).
　断熱層の密度は、特に限定されず、例えば０．２～０．５ｇ／ｃｍ３であり、好ましくは０．３ｇ／ｃｍ３以上、より好ましくは０．３５ｇ／ｃｍ３以上、さらに好ましくは０．３７ｇ／ｃｍ３以上であり、好ましくは０．４５ｇ／ｃｍ３以下である。 The density of the heat insulating layer is not particularly limited and is, for example, 0.2 to 0.5 g/ cm3 , preferably 0.3 g/ cm3 or more, more preferably 0.35 g/ cm3 or more, even more preferably 0.37 g/ cm3 or more, and preferably 0.45 g/ cm3 or less.
　断熱層の８０℃、２ＭＰａ加圧条件における熱伝導率は、好ましくは０．０１０Ｗ／Ｋ・ｍ以上であり、好ましくは０．３Ｗ／Ｋ・ｍ以下、より好ましくは０．１Ｗ／Ｋ・ｍ以下、より好ましくは０．０８Ｗ／Ｋ・ｍ以下、より好ましくは０．０６Ｗ／Ｋ・ｍ以下、より好ましくは０．０５５Ｗ／Ｋ・ｍ以下、より好ましくは０．０４５Ｗ／Ｋ・ｍ以下、さらに好ましくは０．０４Ｗ／Ｋ・ｍ以下である。断熱層の６００℃、２ＭＰａ加圧条件における熱伝導率は、好ましくは０．０１０Ｗ／Ｋ・ｍ以上であり、好ましくは０．３Ｗ／Ｋ・ｍ以下、より好ましくは０．２Ｗ／Ｋ・ｍ以下、より好ましくは０．１Ｗ／Ｋ・ｍ以下、より好ましくは０．０８Ｗ／Ｋ・ｍ以下、さらに好ましくは０．０７５Ｗ／Ｋ・ｍ以下である。 The thermal conductivity of the insulating layer at 80°C and 2 MPa pressure is preferably 0.010 W/K·m or more, and preferably 0.3 W/K·m or less, more preferably 0.1 W/K·m or less, more preferably 0.08 W/K·m or less, more preferably 0.06 W/K·m or less, more preferably 0.055 W/K·m or less, more preferably 0.045 W/K·m or less, and even more preferably 0.04 W/K·m or less. The thermal conductivity of the insulating layer at 600°C and 2 MPa pressure is preferably 0.010 W/K·m or more, and preferably 0.3 W/K·m or less, more preferably 0.2 W/K·m or less, more preferably 0.1 W/K·m or less, more preferably 0.08 W/K·m or less, and even more preferably 0.075 W/K·m or less.
　加圧していないときの厚み（初期厚み）が２ｍｍになるように調製した場合の断熱層の８０℃、２ＭＰａ加圧条件における熱抵抗は、好ましくは０．０２０（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．０２５（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．０３（Ｋ・ｍ２）／Ｗ以上、さらに好ましくは０．０３５（Ｋ・ｍ２）／Ｗ以上であり、好ましくは０．１（Ｋ・ｍ２）／Ｗ以下である。初期厚み２ｍｍの断熱層の６００℃、２ＭＰａ加圧条件における熱抵抗は、好ましくは０．０１０（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．０１５（Ｋ・ｍ２）／Ｗ以上、さらに好ましくは０．０２０（Ｋ・ｍ２）／Ｗ以上であり、好ましくは０．１（Ｋ・ｍ２）／Ｗ以下である。 When the thickness (initial thickness) of the insulating layer is adjusted to 2 mm without pressure, the thermal resistance at 80°C and 2 MPa pressure is preferably 0.020 (K·m 2 )/W or more, more preferably 0.025 (K·m 2 )/W or more, more preferably 0.03 (K·m 2 )/W or more, even more preferably 0.035 (K·m 2 )/W or more, and preferably 0.1 (K·m 2 )/W or less. The thermal resistance of the insulating layer with an initial thickness of 2 mm at 600°C and 2 MPa pressure is preferably 0.010 (K·m 2 )/W or more, more preferably 0.015 (K·m 2 )/W or more, even more preferably 0.020 (K·m 2 )/W or more, and preferably 0.1 (K·m 2 )/W or less.
　断熱層の熱伝導率は、日本産業規格ＪＩＳ Ａ　１４１２－２：１９９９「熱絶縁材の熱抵抗および熱伝導率の測定方法－第２部：熱流計法（ＨＦＭ法）」に記載の方法により測定することができる。 The thermal conductivity of the insulation layer can be measured using the method described in Japanese Industrial Standards JIS A 1412-2:1999 "Methods for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method (HFM method)."
　なお、熱流計法（ＨＦＭ法）は、試験体である平板状の熱絶縁材（断熱層）と標準板とを比較して、熱伝導率、熱抵抗等の伝熱特性を測定する二次測定法または比較測定法である。以下、詳細な測定手順と測定条件を説明する。 The heat flow meter method (HFM method) is a secondary or comparative measurement method that measures heat transfer characteristics such as thermal conductivity and thermal resistance by comparing a flat thermal insulation material (insulation layer) as a test specimen with a standard plate. The detailed measurement procedure and conditions are explained below.
　断熱層を所定の大きさ（例えば、２０ｍｍ×２０ｍｍ）に切断して試験体とし、標準板として、例えば、アルミナコンポジットマテリアル（「ＲＳ－１００」、ＺＩＲＣＡＲ　Ｒｅｆｒａｃｔｏｒｙ　Ｃｏｍｐｏｓｉｔｅｓ，Ｉｎｃ．製、厚さ：５ｍｍ、熱伝導率：０．６６Ｗ／Ｋ・ｍ）等を準備する。次に、空圧プレス機の下盤面に、上から第１熱電対、チタン板、断熱層、チタン板、第２熱電対、標準板および第３熱電対の順に設置し、上盤と下盤を挟んで試験体、標準板、熱電対等を密着させる。そして、上盤と下盤をそれぞれ所定の測定温度に加熱し、さらに所定の測定圧力になるように空圧プレス機によって試験体等に荷重をかけて加圧する。 The insulation layer is cut to a specified size (e.g., 20 mm x 20 mm) to prepare the test specimen, and an alumina composite material ("RS-100", manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W/K·m) is prepared as the standard plate. Next, the first thermocouple, titanium plate, insulation layer, titanium plate, second thermocouple, standard plate, and third thermocouple are placed on the lower plate of the pneumatic press in this order from the top, and the test specimen, standard plate, thermocouple, etc. are tightly pressed between the upper and lower plates. The upper and lower plates are then heated to the specified measurement temperature, and the test specimen, etc. are pressed by applying a load using the pneumatic press to reach the specified measurement pressure.
　なお、測定温度としては、第１熱電対側の上盤の温度を８０℃とし、第３熱電対側の下盤の温度を３０℃とすることが挙げられる。一方、高温条件とするときの測定温度としては、第１熱電対側の上盤の温度を６００℃とし、第３熱電対側の下盤の温度を４０℃とすることが挙げられる。 The measurement temperatures are as follows: the temperature of the upper plate on the first thermocouple side is 80°C, and the temperature of the lower plate on the third thermocouple side is 30°C. On the other hand, the measurement temperatures under high temperature conditions are as follows: the temperature of the upper plate on the first thermocouple side is 600°C, and the temperature of the lower plate on the third thermocouple side is 40°C.
　また、測定圧力としては、２ＭＰａ（荷重：８００Ｎ）とすることが挙げられる。加熱加圧させた状態で、各熱電対の検出温度が安定するまで測定を継続し、温度安定後の各熱電対の検出温度、断熱層の加圧時の厚み、標準板の熱伝導率、標準板の加圧時の厚みから、下記式（Ｉ）により断熱層の熱伝導率ｋ１を算出できる。
　ｋ１＝ｋ２×（Ｌ１×ΔＴ１）／（Ｌ２×ΔＴ２）　・・・（Ｉ）
（式中、ｋ１は断熱層の熱伝導率［Ｗ／（ｍ・Ｋ）］、ｋ２は標準板の熱伝導率［Ｗ／（ｍ・Ｋ）］、Ｌ１は断熱層の加圧時厚み、Ｌ２は標準板の厚み、ΔＴ１は第２熱電対の温度と第３熱電対の温度との温度差、ΔＴ２は第１熱電対の温度と第２熱電対の温度との温度差である。） The measurement pressure may be 2 MPa (load: 800 N). Under the heating and pressurizing condition, the measurement is continued until the temperature detected by each thermocouple stabilizes, and the thermal conductivity k1 of the thermal insulation layer can be calculated from the temperature detected by each thermocouple after the temperature stabilizes, the thickness of the thermal insulation layer when pressed, the thermal conductivity of the standard plate, and the thickness of the standard plate when pressed, according to the following formula (I).
k1=k2×(L1×ΔT1)/(L2×ΔT2) (I)
(In the formula, k1 is the thermal conductivity of the insulating layer [W/(m K)], k2 is the thermal conductivity of the standard plate [W/(m K)], L1 is the thickness of the insulating layer when pressed, L2 is the thickness of the standard plate, ΔT1 is the temperature difference between the temperatures of the second thermocouple and the third thermocouple, and ΔT2 is the temperature difference between the temperatures of the first thermocouple and the second thermocouple.)
　なお、検出温度が安定するとは、１０分経時前後での温度変化が所定の範囲内（例えば、±０．１℃以内）になることとすることが挙げられる。 The detected temperature is stabilized when the temperature change after about 10 minutes is within a specified range (for example, within ±0.1°C).
　断熱層の熱抵抗は、前述の熱伝導率ｋ１と加圧時厚みＬ１から、下記式（ＩＩ）により算出することができる。
　Ｒ１＝Ｌ１／ｋ１　・・・（ＩＩ）
（式中、Ｒ１は断熱層の熱抵抗［（ｍ２・Ｋ）／Ｗ］、ｋ１は断熱層の熱伝導率［Ｗ／（ｍ・Ｋ）］、Ｌ１は断熱層の加圧時厚み［ｍ］である。） The thermal resistance of the heat insulating layer can be calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 according to the following formula (II).
R1=L1/k1 (II)
(In the formula, R1 is the thermal resistance of the insulating layer [( m2 ·K)/W], k1 is the thermal conductivity of the insulating layer [W/(m·K)], and L1 is the thickness of the insulating layer when pressed [m].)
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する断熱層は、該断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、圧縮応力値が３．４５ＭＰａのときの圧縮ひずみの値（以下、「３．４５ＭＰａ圧縮時ひずみ」ともいう。他の類似表現も同様である。）が、例えば５５％以下または５０％以下であってよく、断熱層の耐久性や該断熱層からの粉体発生（例えば、無機粒子の脱落による粉体発生）の抑制等の観点から、４０％以下であることが有利であり、３５％以下または３０％以下であることが好ましく、２５％以下または２０％以下であってもよい。上記断熱層の３．４５ＭＰａ圧縮時ひずみは、０％超であり、例えば７％以上であってよく、１０％以上、１２％以上、１５％以上または２０％以上であってもよい。３．４５ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある断熱層は、ここに開示されるいずれかの緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the insulation material disclosed herein, when a compression test is performed on the insulation layer alone at a compression speed of 0.5 mm/min, the value of the compressive strain when the compressive stress value is 3.45 MPa (hereinafter also referred to as "strain at 3.45 MPa compression"; other similar expressions are the same) may be, for example, 55% or less or 50% or less, and from the viewpoint of the durability of the insulation layer and the suppression of powder generation from the insulation layer (for example, powder generation due to falling off of inorganic particles), it is advantageous to have a value of 40% or less, and preferably a value of 35% or less or 30% or less, and may be 25% or less or 20% or less. The 3.45 MPa compression strain of the insulation layer is more than 0%, and may be, for example, 7% or more, or may be 10% or more, 12% or more, 15% or more, or 20% or more. An insulating layer having a 3.45 MPa compressive strain within any of the ranges described above, when combined with any of the buffer layers disclosed herein, is likely to produce an insulating material with good insulation and buffer properties (e.g., good compression characteristics in the loading-unloading test under high pressure conditions described below).
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する断熱層の１．３９ＭＰａ圧縮時ひずみは、例えば４５％以下または４０％以下であってよく、耐久性や粉体発生抑制等の観点から、３０％以下または２５％以下であることが好ましく、２０％以下であることが有利であり、１８％以下、１５％以下または１３％以下であってもよい。上記断熱層の１．３９ＭＰａ圧縮時ひずみは、０％超であり、例えば５％以上であってよく、７％以上、１０％以上、１２％以上または１５％以上であってもよい。１．３９ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある断熱層は、ここに開示されるいずれかの緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the thermal insulation material disclosed herein, the 1.39 MPa compression strain of the thermal insulation layer constituting the thermal insulation material may be, for example, 45% or less or 40% or less, and from the viewpoints of durability and suppression of powder generation, etc., it is preferably 30% or less or 25% or less, advantageously 20% or less, and may be 18% or less, 15% or less, or 13% or less. The 1.39 MPa compression strain of the above-mentioned thermal insulation layer is more than 0%, and may be, for example, 5% or more, 7% or more, 10% or more, 12% or more, or 15% or more. When combined with any of the buffer layers disclosed herein, a thermal insulation material having good thermal insulation and buffer properties (for example, good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) is easily realized.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する断熱層の１．００ＭＰａ圧縮時ひずみは、例えば４０％以下であることが適当であり、２５％以下または２０％以下であることが好ましく、１８％以下であることが有利であり、１５％以下、１２％以下または１０％以下であってもよい。上記断熱層の１．００ＭＰａ圧縮時ひずみは、０％超であり、例えば４％以上であってよく、６％以上、８％以上、１０％以上または１２％以上であってもよい。１．００ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある断熱層は、ここに開示されるいずれかの緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the insulating material disclosed herein, the 1.00 MPa compression strain of the insulating layer constituting the insulating material is, for example, suitably 40% or less, preferably 25% or less or 20% or less, advantageously 18% or less, and may be 15% or less, 12% or less, or 10% or less. The 1.00 MPa compression strain of the insulating layer is greater than 0%, and may be, for example, 4% or more, 6% or more, 8% or more, 10% or more, or 12% or more. An insulating layer having a 1.00 MPa compression strain in any of the above-mentioned ranges is likely to realize an insulating material having good insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described below) in combination with any of the buffer layers disclosed herein.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する断熱層は、０．３４ＭＰａ圧縮時ひずみが３０％以下であることが適当であり、２０％以下であることが好ましく、１５％以下であることがより好ましい。上記断熱層の０．３４ＭＰａ圧縮時ひずみは、０％超であり、例えば３％以上であってよく、５％以上、７％以上または９％以上であってもよい。０．３４ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある断熱層は、ここに開示されるいずれかの緩衝層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the insulating material disclosed herein, the insulating layer constituting the insulating material suitably has a strain at 0.34 MPa compression of 30% or less, preferably 20% or less, and more preferably 15% or less. The strain at 0.34 MPa compression of the insulating layer is greater than 0%, and may be, for example, 3% or more, 5% or more, 7% or more, or 9% or more. An insulating layer having a strain at 0.34 MPa compression in any of the above-mentioned ranges is likely to realize an insulating material with good insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described below) in combination with any of the buffer layers disclosed herein.
　断熱層の数は、通常、１以上であり、通常、１０以下、好ましくは７以下、さらに好ましくは５以下である。ここに開示される技術は、断熱層の数が３以下または２以下（典型的には１）である態様で好ましく実施することができる。 The number of insulating layers is typically 1 or more, and typically 10 or less, preferably 7 or less, and more preferably 5 or less. The technology disclosed herein can be preferably implemented in an embodiment in which the number of insulating layers is 3 or less or 2 or less (typically 1).
　断熱層は、隣接する層と接着剤または粘着剤により接合されていてもよく、また接着剤または粘着剤により接合されていなくてもよく、接着剤または粘着剤により接合されていないことが好ましい。接着剤または粘着剤により接合されていない、すなわち接着剤または粘着剤を使用しないことで、使用している場合よりも熱伝導率を低減することができる。 The insulating layer may be bonded to adjacent layers with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the insulating layer is not bonded with an adhesive or pressure-sensitive adhesive. By not bonding with an adhesive or pressure-sensitive adhesive, i.e., by not using an adhesive or pressure-sensitive adhesive, the thermal conductivity can be reduced compared to when an adhesive or pressure-sensitive adhesive is used.
　断熱層の形状は、特に限定されないが、平面視した場合の形状としては、例えば、四角形等の多角形、円形、楕円形等が挙げられる。四角形の例としては矩形（正方形および長方形を包含する。）が挙げられる。 The shape of the insulating layer is not particularly limited, but examples of shapes when viewed in a plane include polygons such as quadrangles, circles, ellipses, etc. Examples of quadrangles include rectangles (including squares and rectangles).
（緩衝層）
　緩衝層は、繊維を含んでなる繊維成形体（以下、「繊維成形体」と略す場合がある。）または発泡体を含んでなる発泡成形体（以下、「発泡成形体」と略す場合がある。）からなる層である。ここで「繊維を含んでなる繊維成形体からなる層」とは、構成材料として少なくとも繊維を含み、層状に成形されたものを意味し、「発泡体を含んでなる発泡成形体からなる層」とは、構成材料として少なくとも発泡体を含み、層状に成形されたものを意味する。以下、繊維成形体、発泡成形体等について詳細に説明する。 (Buffer layer)
The buffer layer is a layer made of a fiber-containing molded body (hereinafter sometimes abbreviated as "fiber-containing molded body") or a foam-containing molded body (hereinafter sometimes abbreviated as "foam-containing molded body"). Here, "a layer made of a fiber-containing molded body" means a layer containing at least fiber as a constituent material, and "a layer made of a foam-containing molded body" means a layer containing at least foam as a constituent material. Hereinafter, fiber-containing molded bodies, foam-containing molded bodies, etc. will be described in detail.
　いくつかの態様における緩衝層は、繊維を含んでなる成形体（繊維成形体）である。前述した断熱層も無機粒子および無機繊維を含む混合物を成形した成形体であることが好ましいため、断熱層がこのような成形体である場合には、緩衝層における繊維成形体との区別は、無機粒子を含んでいるか否かで判断することができる。すなわち、無機粒子を含んでいる層を断熱層と、無機粒子を含まず、繊維を含んで成形された層を緩衝層として判断することができる。緩衝層における繊維成形体は、無機粒子を含まず、繊維を含んでなる成形体であることが好ましい。 In some embodiments, the buffer layer is a molded body (fiber molded body) containing fibers. Since the aforementioned heat insulating layer is also preferably a molded body formed from a mixture containing inorganic particles and inorganic fibers, when the heat insulating layer is such a molded body, it can be distinguished from the fiber molded body in the buffer layer by whether or not it contains inorganic particles. In other words, a layer containing inorganic particles can be determined as the heat insulating layer, and a layer not containing inorganic particles but containing fibers can be determined as the buffer layer. The fiber molded body in the buffer layer is preferably a molded body not containing inorganic particles but containing fibers.
　繊維成形体の繊維の種類は、特に限定されないが、断熱層と同様に無機繊維と有機繊維に分類することができる。具体例としては、グラスウール、ロックウール、グラスマット（グラスニードルマット）等の無機繊維、セルロースファイバー、ポリエステル、ポリプロピレン等からなるフェルト等の有機繊維が挙げられるが、無機繊維が好ましく、グラスウールが特に好ましい。グラスウールは、繊維および熱硬化性樹脂（例えばフェノールバインダー）を含む硬化物であり、繊維同士が熱硬化性樹脂で接合されている。また、圧縮応力を高め、かつ緩衝機能を発揮させる効果がある。なお、繊維成形体は、１種類の繊維を含んでいてもよいし、２種類以上の繊維を含んでいてもよい。また、繊維の集合形態は、不織布、織物、編物等のいずれであってもよく、例えば不織布の形態である。 The type of fiber in the fiber molding is not particularly limited, but can be classified into inorganic and organic fibers, as in the heat insulating layer. Specific examples include inorganic fibers such as glass wool, rock wool, and glass mat (glass needle mat), and organic fibers such as cellulose fiber, polyester, and felt made of polypropylene, etc., but inorganic fibers are preferred, and glass wool is particularly preferred. Glass wool is a hardened material containing fibers and a thermosetting resin (e.g., a phenol binder), and the fibers are bonded together with the thermosetting resin. It also has the effect of increasing compressive stress and exerting a buffer function. The fiber molding may contain one type of fiber, or may contain two or more types of fibers. The fiber assembly may be in the form of a nonwoven fabric, woven fabric, knitted fabric, etc., for example, a nonwoven fabric.
　繊維成形体における繊維の含有量は、特に限定されず、例えば５０質量％以上（典型的には５０質量％～９９質量％）であり、好ましくは６０質量％以上、より好ましくは７０質量％以上、さらに好ましくは８０質量％以上（例えば８２質量％以上）であり、好ましくは９７質量％以下、より好ましくは９５質量％以下、さらに好ましくは９３質量％以下である。繊維の含有量が上記範囲内であると、繊維成形体は緩衝性を発揮し易くなる。 The fiber content in the fiber molding is not particularly limited, and is, for example, 50% by mass or more (typically 50% by mass to 99% by mass), preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more (for example, 82% by mass or more), and preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 93% by mass or less. When the fiber content is within the above range, the fiber molding is more likely to exhibit cushioning properties.
　繊維成形体の繊維の平均繊維長は、特に限定されず、例えば１ｍｍ～２００ｍｍであり、好ましくは５ｍｍ以上、より好ましくは１０ｍｍ以上、さらに好ましくは２０ｍｍ以上であり、好ましくは１７５ｍｍ以下、より好ましくは１５０ｍｍ以下、さらに好ましくは１２５ｍｍ以下である。繊維の平均繊維長が上記範囲内であると、緩衝性が発揮し易くなる。 The average fiber length of the fibers in the fiber molding is not particularly limited, and is, for example, 1 mm to 200 mm, preferably 5 mm or more, more preferably 10 mm or more, even more preferably 20 mm or more, and preferably 175 mm or less, more preferably 150 mm or less, even more preferably 125 mm or less. If the average fiber length of the fibers is within the above range, it becomes easier for the fibers to exhibit cushioning properties.
　繊維成形体の繊維の平均繊維径は、特に限定されず、例えば３μｍ～１３μｍであり、好ましくは４μｍ以上、より好ましくは４．５μｍ以上、さらに好ましくは５μｍ以上であり、好ましくは１０μｍ以下、より好ましくは９μｍ以下、さらに好ましくは８μｍ以下である。繊維の平均繊維径が上記範囲内であると、繊維成形体は、緩衝性と低熱伝導率を両立し易くなる。 The average fiber diameter of the fibers in the fiber molding is not particularly limited, and is, for example, 3 μm to 13 μm, preferably 4 μm or more, more preferably 4.5 μm or more, even more preferably 5 μm or more, and preferably 10 μm or less, more preferably 9 μm or less, even more preferably 8 μm or less. When the average fiber diameter of the fibers is within the above range, the fiber molding is more likely to achieve both cushioning properties and low thermal conductivity.
　繊維成形体は、繊維に加えてバインダー（結合剤）を含むことが好ましい。繊維成形体のバインダーの種類は、特に限定されないが、有機バインダーと無機バインダーに分類することができる。 The fiber molding preferably contains a binder in addition to the fibers. The type of binder in the fiber molding is not particularly limited, but can be classified into organic binders and inorganic binders.
　有機バインダーの具体例としては、熱可塑性樹脂、熱可塑性エラストマー、熱硬化性樹脂、熱硬化性エラストマー、糖類、水溶性高分子等が挙げられる。無機バインダーの具体例としては、酸化アルミニウム、酸化ジルコニウム、酸化マグネシウム、酸化チタン、酸化カルシウム等が挙げられる。バインダーが上述したものであると、形状安定性が向上する。なお、繊維成形体は、１種類のバインダーを含んでいてもよいし、２種類以上のバインダーを含んでいてもよい。 Specific examples of organic binders include thermoplastic resins, thermoplastic elastomers, thermosetting resins, thermosetting elastomers, sugars, water-soluble polymers, etc. Specific examples of inorganic binders include aluminum oxide, zirconium oxide, magnesium oxide, titanium oxide, calcium oxide, etc. When the binder is one of the above, shape stability is improved. The fiber molding may contain one type of binder or two or more types of binders.
　繊維成形体におけるバインダーの含有量は、特に限定されず、例えば該繊維成形体の１質量％～５０質量％であり、好ましくは２質量％以上、より好ましくは５質量％以上、さらに好ましくは７質量％以上であり、１０質量％以上または１２質量％以上であってもよく、また、好ましくは４０質量％以下、より好ましくは３０質量％以下、さらに好ましくは２０質量％以下であり、１８質量％以下または１６質量％以下であってもよい。バインダーの含有量が上記範囲内であると、低熱伝導率かつ緩衝性が良好になる。 The binder content in the fiber molding is not particularly limited, and may be, for example, 1% to 50% by mass of the fiber molding, preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and may be 10% by mass or more or 12% by mass or more, and may be 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and may be 18% by mass or less or 16% by mass or less. When the binder content is within the above range, low thermal conductivity and good cushioning properties are achieved.
　繊維成形体は、親水性フュームドシリカを含まず、かつ繊維およびバインダーを含む混合物を成形した成形体であることが好ましい。なお、繊維成形体に使用する繊維には、バインダーとしての熱硬化性樹脂が分散された状態（繊維の少なくとも一部に付着した状態）で販売されているものがあり、このような繊維は、目的の形態に切断した後、加熱圧縮することで繊維成形体とすることができる。 The fiber molding is preferably a molding that does not contain hydrophilic fumed silica and is formed from a mixture that contains fibers and a binder. Some fibers used in fiber moldings are sold with a thermosetting resin dispersed as a binder (attached to at least a portion of the fibers). Such fibers can be cut to the desired shape and then heated and compressed to form a fiber molding.
　発泡成形体は、発泡体を含んでなる成形体である。上記発泡体の材質は、通常、熱可塑性樹脂、熱硬化性樹脂等の樹脂である。上記発泡体の成形は、公知の成形方法とその条件を適宜採用して行うことができる。 A foamed molded product is a molded product that contains a foam. The material of the foam is usually a resin such as a thermoplastic resin or a thermosetting resin. The foam can be molded by appropriately adopting a known molding method and its conditions.
　発泡体成形体の発泡体の樹脂の種類は、特に限定されず、具体例としては、ポリエチレン、ポリプロピレン等のポリオレフィン系樹脂、ポリエチレンテレフタレート樹脂、塩化ビニル樹脂（ＰＶＣ）、ポリスチレン等のスチロール系樹脂、ポリウレタン樹脂等のポリウレタン系樹脂、フェノール樹脂（ＰＦ）等のレゾール型フェノール樹脂、メラミン樹脂（ＭＦ）等のメラミン系樹脂、エポキシ樹脂（ＥＰ）等のエポキシ系樹脂、天然ゴム（ＮＲ）、スチレンブタジエンゴム（ＳＢＲ）、クロロプレンゴム（ＣＲ）、ニトリルゴム（ＮＢＲ）、ポリウレタン等の樹脂から形成された発泡フォーム等が挙げられる。 The type of resin in the foam of the foam molded body is not particularly limited, and specific examples include polyolefin resins such as polyethylene and polypropylene, polyethylene terephthalate resin, polyvinyl chloride resin (PVC), styrene resins such as polystyrene, polyurethane resins such as polyurethane resin, resol-type phenolic resins such as phenolic resin (PF), melamine resins such as melamine resin (MF), epoxy resins such as epoxy resin (EP), and foams formed from resins such as natural rubber (NR), styrene butadiene rubber (SBR), chloroprene rubber (CR), nitrile rubber (NBR), and polyurethane.
　発泡成形体の気泡構造は、独立気泡であってもよく、連続気泡であってもよく、目的の物理的性質等に応じて適宜選択することができる。 The cell structure of the foamed molded product may be either closed or open, and can be selected appropriately depending on the desired physical properties, etc.
　緩衝層の厚みは、例えば０．５ｍｍ～１０ｍｍであり、好ましくは１ｍｍ以上、より好ましくは１．５ｍｍ以上、さらに好ましくは２ｍｍ以上であり、好ましくは７ｍｍ以下、より好ましくは６ｍｍ以下、さらに好ましくは５ｍｍ以下である。緩衝層の厚みが上記範囲内であると、バッテリー膨張で発生した応力を適切に緩衝することができる。なお、緩衝層の厚みとしては、断熱層と同様に、厚さ測定器（デジタルシックネスゲージＪＡＮ－２５７、測定子Φ２０ｍｍ、尾崎製作所製）を使用して緩衝層の断面の厚みを測定し、さらにこの測定を任意の数か所（例えば、１０ヶ所）で行って得られた数値群の平均値を採用することができる。 The thickness of the buffer layer is, for example, 0.5 mm to 10 mm, preferably 1 mm or more, more preferably 1.5 mm or more, even more preferably 2 mm or more, and preferably 7 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less. If the thickness of the buffer layer is within the above range, it can adequately buffer the stress generated by the expansion of the battery. As with the insulating layer, the thickness of the buffer layer's cross section can be measured using a thickness gauge (digital thickness gauge JAN-257, probe Φ20 mm, manufactured by Ozaki Manufacturing Co., Ltd.), and the average value of the numerical values obtained by performing this measurement at any number of locations (for example, 10 locations) can be used as the thickness of the buffer layer.
　緩衝層の熱伝導率は、特に限定されない。いくつかの態様において、緩衝層の８０℃、２ＭＰａ条件下における熱伝導率は、好ましくは０．０３０Ｗ／Ｋ・ｍ以上、より好ましくは０．０４０Ｗ／Ｋ・ｍ以上、さらに好ましくは０．０５０Ｗ／Ｋ・ｍ以上であり、好ましくは０．２Ｗ／Ｋ・ｍ以下、より好ましくは０．１５Ｗ／Ｋ・ｍ以下、さらに好ましくは０．１Ｗ／Ｋ・ｍ以下である。また、いくつかの態様において、緩衝層の６００℃、２ＭＰａ条件下での熱伝導率は、好ましくは０．０４Ｗ／Ｋ・ｍ以上、より好ましくは０．０５Ｗ／Ｋ・ｍ以上、さらに好ましくは０．０６Ｗ／Ｋ・ｍ以上であり、好ましくは０．３０Ｗ／Ｋ・ｍ以下、より好ましくは０．２５Ｗ／Ｋ・ｍ以下、さらに好ましくは０．２０Ｗ／Ｋ・ｍ以下である。なお、緩衝層の熱伝導率は、上述した断熱層の熱伝導率の測定方法と同様の方法により測定することができる。 The thermal conductivity of the buffer layer is not particularly limited. In some embodiments, the thermal conductivity of the buffer layer at 80°C and 2 MPa is preferably 0.030 W/K·m or more, more preferably 0.040 W/K·m or more, and even more preferably 0.050 W/K·m or more, and is preferably 0.2 W/K·m or less, more preferably 0.15 W/K·m or less, and even more preferably 0.1 W/K·m or less. In some embodiments, the thermal conductivity of the buffer layer at 600°C and 2 MPa is preferably 0.04 W/K·m or more, more preferably 0.05 W/K·m or more, and even more preferably 0.06 W/K·m or more, and is preferably 0.30 W/K·m or less, more preferably 0.25 W/K·m or less, and even more preferably 0.20 W/K·m or less. The thermal conductivity of the buffer layer can be measured by the same method as the method for measuring the thermal conductivity of the insulating layer described above.
　緩衝層の熱抵抗は、特に限定されない。いくつかの態様において、緩衝層の８０℃、２ＭＰａ条件下における熱抵抗は、好ましくは０．０２０（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．０２５（Ｋ・ｍ２）／Ｗ以上、さらに好ましくは０．０３（Ｋ・ｍ２）／Ｗ以上であり、好ましくは０．０７（Ｋ・ｍ２）／Ｗ以下、より好ましくは０．０６（Ｋ・ｍ２）／Ｗ以下、さらに好ましくは０．０５（Ｋ・ｍ２）／Ｗ以下である。また、いくつかの態様において、緩衝層の６００℃、２ＭＰａ条件下での熱抵抗は、好ましくは０．００１（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．００３（Ｋ・ｍ２）／Ｗ以上、さらに好ましくは０．００５（Ｋ・ｍ２）／Ｗ以上であり、好ましくは０．１（Ｋ・ｍ２）／Ｗ以下、より好ましくは０．０５（Ｋ・ｍ２）／Ｗ以下、さらに好ましくは０．０１（Ｋ・ｍ２）／Ｗ以下である。なお、緩衝層の熱抵抗は、上述した断熱層の熱伝導率の測定方法と同様の方法により測定することができる。 The thermal resistance of the buffer layer is not particularly limited. In some embodiments, the thermal resistance of the buffer layer under conditions of 80° C. and 2 MPa is preferably 0.020 (K·m 2 )/W or more, more preferably 0.025 (K·m 2 )/W or more, even more preferably 0.03 (K·m 2 )/W or more, and preferably 0.07 (K·m 2 )/W or less, more preferably 0.06 (K·m 2 )/W or less, even more preferably 0.05 (K·m 2 )/W or less. In some embodiments, the thermal resistance of the buffer layer at 600°C and 2 MPa is preferably 0.001 (K· m2 )/W or more, more preferably 0.003 (K· m2 )/W or more, even more preferably 0.005 (K· m2 )/W or more, and preferably 0.1 (K· m2 )/W or less, more preferably 0.05 (K· m2 )/W or less, even more preferably 0.01 (K· m2 )/W or less. The thermal resistance of the buffer layer can be measured by the same method as the method for measuring the thermal conductivity of the heat insulating layer described above.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する緩衝層は、該緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、圧縮応力値が３．４５ＭＰａのときの圧縮ひずみの値（以下、「３．４５ＭＰａ圧縮時ひずみ」ともいう。他の類似表現も同様である。）が、例えば２５％以上であってよく、３０％以上または３５％以上であることが有利であり、４０％以上であることが好ましく、４５％以上であることがより好ましく、５０％以上または５５％以上であってもよい。上記緩衝層の３．４５ＭＰａ圧縮時ひずみは、例えば９０％以下であってよく、８５％以下（例えば８５％未満）、８０％以下または７５％以下であってもよい。３．４５ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある緩衝層は、ここに開示されるいずれかの断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the thermal insulation material disclosed herein, when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min, the value of the compressive strain when the compressive stress value is 3.45 MPa (hereinafter also referred to as "3.45 MPa compression strain"; other similar expressions are the same) may be, for example, 25% or more, advantageously 30% or more or 35% or more, preferably 40% or more, more preferably 45% or more, and may be 50% or more or 55% or more. The 3.45 MPa compression strain of the buffer layer may be, for example, 90% or less, 85% or less (e.g., less than 85%), 80% or less, or 75% or less. A buffer layer having a 3.45 MPa compression strain in any of the above-mentioned ranges is likely to realize a thermal insulation material with good thermal insulation and cushioning properties (for example, good compression characteristics in a loading-unloading test under high pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する緩衝層の１．３９ＭＰａ圧縮時ひずみは、例えば２５％以上であってよく、３５％以上であることが有利であり、４５％以上であることが好ましく、５０％以上または５５％以上であることがより好ましく、６０％以上または６５％以上であってもよい。上記緩衝層の１．３９ＭＰａ圧縮時ひずみは、例えば９０％以下であってよく、８０％以下であることが好ましく、７５％以下であってもよい。１．３９ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある緩衝層は、ここに開示されるいずれかの断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する低圧力条件での載荷－除荷試験における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the insulating material disclosed herein, the 1.39 MPa compression strain of the buffer layer constituting the insulating material may be, for example, 25% or more, advantageously 35% or more, preferably 45% or more, more preferably 50% or more or 55% or more, and may be 60% or more or 65% or more. The 1.39 MPa compression strain of the buffer layer may be, for example, 90% or less, preferably 80% or less, and may be 75% or less. A buffer layer having a 1.39 MPa compression strain in any of the above-mentioned ranges is likely to realize an insulating material with good insulation and cushioning properties (for example, good compression characteristics in a loading-unloading test under low pressure conditions described below) when combined with any of the insulating layers disclosed herein.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する緩衝層の１．００ＭＰａ圧縮時ひずみは、例えば５％以上であってよく、７％以上または１０％以上であることが好ましく、１５％以上、２０％以上、２５％以上、３０％以上、３５％以上、４０％以上、５０％以上、５５％以上または６０％以上であってもよい。上記緩衝層の１．００ＭＰａ圧縮時ひずみは、例えば８５％以下であってよく、８０％以下であることが好ましく、７５％以下または７０％以下であってもよい。１．００ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある緩衝層は、ここに開示されるいずれかの断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the thermal insulation material disclosed herein, the strain at 1.00 MPa compression of the buffer layer constituting the thermal insulation material may be, for example, 5% or more, preferably 7% or more or 10% or more, and may be 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, 50% or more, 55% or more, or 60% or more. The strain at 1.00 MPa compression of the buffer layer may be, for example, 85% or less, preferably 80% or less, and may be 75% or less or 70% or less. A buffer layer having a strain at 1.00 MPa compression in any of the above-mentioned ranges is likely to realize a thermal insulation material having good thermal insulation and cushioning properties (for example, good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
　ここに開示される断熱材のいくつかの態様において、該断熱材を構成する緩衝層の０．３４ＭＰａ圧縮時ひずみは、例えば３％以上または５％以上またはであってよく、１０％以上であることが好ましく、１５％以上、２０％以上、２５％以上、３０％以上、３５％以上、４０％以上または４５％以上であってもよい。上記緩衝層の０．３４ＭＰａ圧縮時ひずみは、例えば７５％以下であってよく、７０％以下であることが好ましく、６５％以下、６０％以下、５０％以下、４０％以下、３５％以下、２５％以下または２０％以下であってもよい。０．３４ＭＰａ圧縮時ひずみが上述したいずれかの範囲にある緩衝層は、ここに開示されるいずれかの断熱層との組合せにおいて、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。 In some embodiments of the thermal insulation material disclosed herein, the 0.34 MPa compression strain of the buffer layer constituting the thermal insulation material may be, for example, 3% or more, 5% or more, preferably 10% or more, and may be 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 45% or more. The 0.34 MPa compression strain of the buffer layer may be, for example, 75% or less, preferably 70% or less, and may be 65% or less, 60% or less, 50% or less, 40% or less, 35% or less, 25% or less, or 20% or less. A buffer layer having a 0.34 MPa compression strain in any of the above-mentioned ranges is likely to realize a thermal insulation material having good thermal insulation and cushioning properties (for example, good compression properties in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions described later) in combination with any of the thermal insulation layers disclosed herein.
　ここに開示される断熱材のいくつかの態様において、断熱層の０．３４ＭＰａ圧縮時ひずみ［％］に対する緩衝層の０．３４ＭＰａ圧縮時ひずみ［％］の比（すなわち、０．３４ＭＰａ圧縮時ひずみ比（緩衝層／断熱層））は、０．５以上であることが適当であり、０．７５以上であることが有利であり、１．０以上（例えば１．０超）であることが好ましい。上記０．３４ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）を満たす断熱層と緩衝層の組合せによると、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。低圧力条件での載荷－除荷試験においてより良好な圧縮特性を示す断熱材を得やすくする観点から、いくつかの態様において、上記０．３４ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）は、２．０以上であることが好ましく、３．０以上であることがより好ましく、３．５以上または４．０以上であってもよい。 In some embodiments of the insulating material disclosed herein, the ratio of the strain at 0.34 MPa compression [%] of the buffer layer to the strain at 0.34 MPa compression [%] of the insulating layer (i.e., the strain ratio at 0.34 MPa compression (buffer layer/insulating layer)) is suitably 0.5 or greater, advantageously 0.75 or greater, and preferably 1.0 or greater (e.g., greater than 1.0). A combination of an insulating layer and a buffer layer that satisfies the above-mentioned strain ratio at 0.34 MPa compression (buffer layer/insulating layer) makes it easy to realize an insulating material that has good insulation and cushioning properties (e.g., good compression characteristics in one or both of the loading-unloading tests under high pressure conditions and the loading-unloading tests under low pressure conditions described below). From the viewpoint of making it easier to obtain an insulating material that exhibits better compression characteristics in a load-unload test under low pressure conditions, in some embodiments, the above-mentioned strain ratio at 0.34 MPa compression (buffer layer/insulating layer) is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more or 4.0 or more.
　ここに開示される断熱材のいくつかの態様において、断熱層の１．００ＭＰａ圧縮時ひずみ［％］に対する緩衝層の１．００ＭＰａ圧縮時ひずみ［％］の比（すなわち、１．００ＭＰａ圧縮時ひずみ比（緩衝層／断熱層））は、０．５以上であることが適当であり、０．７５以上であることが有利であり、１．０以上（例えば１．０超）であることが好ましい。上記１．００ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）を満たす断熱層と緩衝層の組合せによると、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。低圧力条件での載荷－除荷試験においてより良好な圧縮特性を示す断熱材を得やすくする観点から、いくつかの態様において、上記１．００ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）は、２．０以上であることが好ましく、３．０以上であることがより好ましく、３．５以上または４．０以上であってもよい。 In some embodiments of the insulating material disclosed herein, the ratio of the strain at 1.00 MPa compression [%] of the buffer layer to the strain at 1.00 MPa compression [%] of the insulating layer (i.e., the strain ratio at 1.00 MPa compression (buffer layer/insulating layer)) is suitably 0.5 or greater, advantageously 0.75 or greater, and preferably 1.0 or greater (e.g., greater than 1.0). A combination of an insulating layer and a buffer layer that satisfies the above-mentioned strain ratio at 1.00 MPa compression (buffer layer/insulating layer) makes it easy to realize an insulating material that has good insulation and cushioning properties (e.g., good compression characteristics in one or both of the loading-unloading tests under high pressure conditions and the loading-unloading tests under low pressure conditions described below). From the viewpoint of making it easier to obtain an insulating material that exhibits better compression characteristics in a load-unload test under low pressure conditions, in some embodiments, the above-mentioned strain ratio at 1.00 MPa compression (buffer layer/insulating layer) is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more or 4.0 or more.
　ここに開示される断熱材のいくつかの態様において、断熱層の１．３９ＭＰａ圧縮時ひずみ［％］に対する緩衝層の１．３９ＭＰａ圧縮時ひずみ［％］の比（すなわち、１．３９ＭＰａ圧縮時ひずみ比（緩衝層／断熱層））は、０．５以上であることが適当であり、０．７５以上であることが有利であり、１．０以上（例えば１．０超）であることが好ましい。上記１．３９ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）を満たす断熱層と緩衝層の組合せによると、良好な断熱性と緩衝性（例えば、後述する高圧力条件での載荷－除荷試験および低圧力条件での載荷－除荷試験の一方または両方における良好な圧縮特性）とを備えた断熱材を実現しやすい。低圧力条件での載荷－除荷試験においてより良好な圧縮特性を示す断熱材を得やすくする観点から、いくつかの態様において、上記１．３９ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）は、２．０以上であることが好ましく、３．０以上であることがより好ましく、３．５以上であってもよい。 In some embodiments of the thermal insulation material disclosed herein, the ratio of the strain at 1.39 MPa compression [%] of the buffer layer to the strain at 1.39 MPa compression [%] of the thermal insulation layer (i.e., the 1.39 MPa compression strain ratio (buffer layer/thermal insulation layer)) is suitably 0.5 or more, advantageously 0.75 or more, and preferably 1.0 or more (e.g., more than 1.0). A combination of a thermal insulation layer and a buffer layer that satisfies the above 1.39 MPa compression strain ratio (buffer layer/thermal insulation layer) makes it easy to realize a thermal insulation material with good thermal insulation and cushioning properties (e.g., good compression characteristics in one or both of the loading-unloading test under high pressure conditions and the loading-unloading test under low pressure conditions, which will be described later). From the viewpoint of making it easier to obtain a thermal insulation material that shows better compression characteristics in the loading-unloading test under low pressure conditions, in some embodiments, the above 1.39 MPa compression strain ratio (buffer layer/thermal insulation layer) is preferably 2.0 or more, more preferably 3.0 or more, and may be 3.5 or more.
　緩衝層の数は、通常１０以下、好ましくは５以下、さらに好ましくは３以下であり、２でもよく、１でもよい。 The number of buffer layers is usually 10 or less, preferably 5 or less, and more preferably 3 or less, and may be 2 or 1.
　緩衝層は、隣接する層と接着剤または粘着剤により接合されていてもよく、また接着剤または粘着剤により接合されていなくてもよく、接着剤または粘着剤により接合されていないことが好ましい。接着剤または粘着剤により接合されていない、すなわち接着剤または粘着剤を使用しないことで、使用している場合よりも熱伝導率の増加を抑制することができる。 The buffer layer may be bonded to the adjacent layers with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the buffer layer is not bonded with an adhesive or pressure-sensitive adhesive. By not bonding with an adhesive or pressure-sensitive adhesive, i.e., by not using an adhesive or pressure-sensitive adhesive, the increase in thermal conductivity can be suppressed compared to when an adhesive or pressure-sensitive adhesive is used.
　緩衝層の形状は、特に限定されないが、平面視した場合の形状としては、例えば、四角形等の多角形、円形、楕円形等が挙げられる。四角形の例としては矩形（正方形および長方形を包含する。）が挙げられる。 The shape of the buffer layer is not particularly limited, but examples of shapes when viewed in a plane include polygons such as quadrangles, circles, and ellipses. Examples of quadrangles include rectangles (including squares and rectangles).
（被覆層）
　この明細書により開示される断熱材は、被覆層を含むことが好ましい。被覆層は、断熱層の無機粒子等の脱落を抑制したり、断熱層を保護したりする役割を果たす層である。例えば、樹脂フィルムを用いて構成された被覆層を好ましく採用し得る。 (Covering layer)
The heat insulating material disclosed in this specification preferably includes a coating layer. The coating layer is a layer that plays a role in suppressing the falling off of inorganic particles and the like of the heat insulating layer and protecting the heat insulating layer. For example, a coating layer formed using a resin film can be preferably adopted.
　被覆層の樹脂の種類は、特に限定されないが、具体例としては、ポリエチレンテレフタレート（ＰＥＴ）、ポリブチレンテレフタレート（ＰＢＴ）、ポリイミド（ＰＩ）、難燃ポリカーボネート（ＰＣ）、通気性多孔質ポリエチレン（ＰＥ）、難燃ポリエチレン（ＰＥ）、二軸延伸ナイロンフィルム（Ｎｙ）等が挙げられる。通気性多孔質ＰＥとしては、分子量が１００万～７００万であるものが好ましい。 The type of resin for the coating layer is not particularly limited, but specific examples include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide (PI), flame-retardant polycarbonate (PC), breathable porous polyethylene (PE), flame-retardant polyethylene (PE), biaxially oriented nylon film (Ny), etc. Breathable porous PE preferably has a molecular weight of 1 to 7 million.
　被覆層の厚みは、特に限定されず、例えば０．００１ｍｍ～０．２ｍｍであり、好ましくは０．００５ｍｍ以上、より好ましくは０．００７ｍｍ以上、さらに好ましくは０．０１０ｍｍ以上であり、好ましくは０．１５ｍｍ以下、より好ましくは０．１０ｍｍ以下、さらに好ましくは０．０５０ｍｍ以下である。被覆層の厚みが上記範囲内であると、低熱伝導率と機械強度を両立することができる。なお、被覆層の厚みの測定は、断熱層の厚みの測定と同様にして行うことができる。 The thickness of the coating layer is not particularly limited, and is, for example, 0.001 mm to 0.2 mm, preferably 0.005 mm or more, more preferably 0.007 mm or more, even more preferably 0.010 mm or more, and preferably 0.15 mm or less, more preferably 0.10 mm or less, even more preferably 0.050 mm or less. When the thickness of the coating layer is within the above range, it is possible to achieve both low thermal conductivity and mechanical strength. The thickness of the coating layer can be measured in the same manner as the thickness of the insulating layer.
　被覆層の数は、通常、１以上であり、好ましくは２以上であり、通常、５以下であり、好ましくは４以下、さらに好ましくは３以下である。なお、２以上の被覆層は、２枚以上の樹脂フィルムであってもよく、１枚の樹脂フィルムを折り返して２層の被覆層としてもよい。このように折り返した場合の被覆層の数は、２層として考えるものとする。 The number of coating layers is usually 1 or more, preferably 2 or more, and usually 5 or less, preferably 4 or less, and more preferably 3 or less. The 2 or more coating layers may be 2 or more resin films, or a single resin film may be folded back to form 2 coating layers. When folded back in this way, the number of coating layers is considered to be 2.
　断熱材が２層以上の被覆層を含む場合、上記２層以上の被覆層が断熱層を厚み方向から挟んで包接し、それらの被覆層の間隙（上記２層以上の被覆層により区画された空間）が密閉されていてもよい。なお、被覆層の間隙を密閉する方法は、特に限定されないが、例えば、被覆層の外縁にシール部を設けて、被覆層間のシール部同士を貼り合せることが挙げられる。シール部の貼り合せ方法も、特に限定されず、例えば、熱溶着、超音波溶着等を利用した溶着、接着剤、粘着剤等を利用した接着が挙げられる。また、溶着は、被覆層の樹脂を直接溶着させてもよく、別途溶着用の樹脂層を設けて溶着してもよい。 When the insulating material includes two or more coating layers, the two or more coating layers may sandwich and enclose the insulating layer from the thickness direction, and the gaps between the coating layers (the space partitioned by the two or more coating layers) may be sealed. The method for sealing the gaps between the coating layers is not particularly limited, but examples include providing a seal portion on the outer edge of the coating layer and bonding the seal portions between the coating layers. The method for bonding the seal portions is also not particularly limited, and examples include welding using heat welding, ultrasonic welding, etc., and adhesion using adhesives, pressure sensitive adhesives, etc. In addition, welding may be performed by directly welding the resin of the coating layer, or by providing a separate resin layer for welding and welding it.
　被覆層は、隣接する断熱層と接着剤または粘着剤により接合されていてもよく、また接着剤または粘着剤により接合されていなくてもよく、接着剤または粘着剤により接合されていないことが好ましい。 The covering layer may be bonded to the adjacent insulating layer with an adhesive or pressure-sensitive adhesive, or may not be bonded with an adhesive or pressure-sensitive adhesive, and it is preferable that the covering layer is not bonded with an adhesive or pressure-sensitive adhesive.
　断熱材が２層以上の被覆層を含み、上記２層以上の被覆層の間隙が密閉されている場合、被覆層は上記間隙と外部空間とをつなぐ通気口を有することが好ましい。通気口を有することにより、包装方法として、シュリンク包装や、深絞り成形フィルムを用いた包装等を採用することができる。 If the insulation material includes two or more coating layers and the gaps between the two or more coating layers are sealed, it is preferable that the coating layers have an air vent that connects the gaps with the outside space. By having an air vent, shrink packaging, packaging using deep-drawn molded film, etc. can be used as a packaging method.
　被覆層の通気口の数は、通常、１以上であり、好ましくは２以上であり、通常、５０以下であり、好ましくは２５以下であり、さらに好ましくは１０以下である。 The number of ventilation holes in the coating layer is usually 1 or more, preferably 2 or more, and usually 50 or less, preferably 25 or less, and more preferably 10 or less.
　被覆層の通気口の合計開口面積は、通常、０．００００７９ｃｍ２～１０ｃｍ２であることが適当であり、好ましくは０．０００１ｃｍ２以上、より好ましくは０．００５ｃｍ２以上、さらに好ましくは０．０１ｃｍ２以上であり、好ましくは５ｃｍ２以下、より好ましくは４ｃｍ２以下、さらに好ましくは３ｃｍ２以下である。被覆層の通気口の合計開口面積が上記範囲内であると、断熱層からの粉体流出を抑制しやすい。 The total opening area of the ventilation holes in the coating layer is usually 0.000079 cm 2 to 10 cm 2 , preferably 0.0001 cm 2 or more, more preferably 0.005 cm 2 or more, even more preferably 0.01 cm 2 or more, and preferably 5 cm 2 or less, more preferably 4 cm 2 or less, and even more preferably 3 cm 2 or less. When the total opening area of the ventilation holes in the coating layer is within the above range, it is easy to suppress powder outflow from the heat insulating layer.
　被覆層の通気口は、通気膜で被覆されていてもよい。通気膜の通気度は、通常、４ｃｍ３／（ｃｍ2・ｓ）～５００ｃｍ３／（ｃｍ2・ｓ）であることが適当であり、好ましくは７ｃｍ３／（ｃｍ2・ｓ）以上、より好ましくは１０ｃｍ３／（ｃｍ2・ｓ）以上、さらに好ましくは２１ｃｍ３／（ｃｍ2・ｓ）以上であり、好ましくは２５０ｃｍ３／（ｃｍ2・ｓ）以下、より好ましくは２００ｃｍ３／（ｃｍ2・ｓ）以下、さらに好ましくは１００ｃｍ３／（ｃｍ2・ｓ）以下である。 The ventilation hole of the covering layer may be covered with a ventilation film. The ventilation film usually has an air permeability of 4 cm 3 /(cm 2 ·s) to 500 cm 3 /(cm 2 ·s), preferably 7 cm 3 /(cm 2 ·s) or more, more preferably 10 cm 3 /(cm 2 ·s) or more, even more preferably 21 cm 3 /(cm 2 ·s) or more, and preferably 250 cm 3 /(cm 2 ·s) or less, more preferably 200 cm 3 /(cm 2 ·s) or less, even more preferably 100 cm 3 /(cm 2 ·s) or less.
　ここに開示される断熱材は、前述の条件を満たすものであれば、その他は特に限定されない。ここに開示される断熱材のいくつかの態様において、該断熱材の８０℃、２ＭＰａ条件下での熱伝導率は、好ましくは０．０２Ｗ／Ｋ・ｍ以上、より好ましくは０．０３Ｗ／Ｋ・ｍ以上、さらに好ましくは０．０４Ｗ／Ｋ・ｍ以上であり、好ましくは０．２Ｗ／Ｋ・ｍ以下、より好ましくは０．１５Ｗ／Ｋ・ｍ以下、さらに好ましくは０．１０Ｗ／Ｋ・ｍ以下である。なお、断熱材の熱伝導率は、断熱層の熱伝導率と同様の方法により測定される。 The insulating material disclosed herein is not particularly limited as long as it satisfies the above-mentioned conditions. In some embodiments of the insulating material disclosed herein, the thermal conductivity of the insulating material at 80°C and 2 MPa is preferably 0.02 W/K·m or more, more preferably 0.03 W/K·m or more, even more preferably 0.04 W/K·m or more, and preferably 0.2 W/K·m or less, more preferably 0.15 W/K·m or less, even more preferably 0.10 W/K·m or less. The thermal conductivity of the insulating material is measured by the same method as that for the thermal conductivity of the insulating layer.
　加圧していないときの厚みが２ｍｍになるように調製した場合の断熱材の８０℃、２ＭＰａ条件下での熱抵抗は、特に限定されず、好ましくは０．０１（Ｋ・ｍ２）／Ｗ以上、より好ましくは０．０２（Ｋ・ｍ２）／Ｗ以上、さらに好ましくは０．０３（Ｋ・ｍ２）／Ｗ以上であり、好ましくは０．１０（Ｋ・ｍ２）／Ｗ以下、より好ましくは０．０９（Ｋ・ｍ２）／Ｗ以下、さらに好ましくは０．０８（Ｋ・ｍ２）／Ｗ以下である。なお、断熱材の熱抵抗は、断熱層の熱抵抗と同様の方法により測定される。 The thermal resistance of the insulating material when adjusted to have an unpressurized thickness of 2 mm under conditions of 80°C and 2 MPa is not particularly limited, and is preferably 0.01 (K· m2 )/W or more, more preferably 0.02 (K· m2 )/W or more, even more preferably 0.03 (K· m2 )/W or more, and preferably 0.10 (K· m2 )/W or less, more preferably 0.09 (K· m2 )/W or less, even more preferably 0.08 (K· m2 )/W or less. The thermal resistance of the insulating material is measured by the same method as that of the thermal resistance of the insulating layer.
　ここに開示される断熱材は、後述する実施例に記載の方法により行われる高圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験１）において、圧縮過程における圧力０．３４ＭＰａ時の圧縮ひずみを圧力３．４５ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｈｐ））が１５％以上（より好ましくは２０％以上、さらに好ましくは２５％以上）であり、かつ、圧縮解放過程において上記圧縮過程の圧縮応力０．３４ＭＰａと同一変位になる圧縮状態での圧縮ひずみを圧力３．４５ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｈｒ））が５％以上であることが好ましい。上記ひずみ差分（Ｘｈｐ）が３０％以上であり、かつ、上記ひずみ差分（Ｘｈｒ）が６％以上であることがより好ましい。載荷－除荷試験１の圧縮過程および圧縮解放過程において上記のような圧縮特性を示す断熱材は、例えばバッテリーモジュール等においてセル間に配置される断熱材として好ましく用いられて、セルの膨張と収縮の繰り返し等に対して相応の厚みを変動でき、さらに適度な応力を発生しうる緩衝性を発揮し得る。 In the insulating material disclosed herein, in a loading-unloading test under high pressure conditions performed by the method described in the Examples below (i.e., loading-unloading test 1), it is preferable that the value (strain difference (Xhp)) obtained by subtracting the compressive strain at a pressure of 0.34 MPa during the compression process from the compressive strain at a pressure of 3.45 MPa is 15% or more (more preferably 20% or more, and even more preferably 25% or more), and that the value (strain difference (Xhr)) obtained by subtracting the compressive strain in a compressed state that results in the same displacement as the compressive stress of 0.34 MPa during the compression process during the compression-release process from the compressive strain at a pressure of 3.45 MPa is 5% or more. It is more preferable that the strain difference (Xhp) is 30% or more, and that the strain difference (Xhr) is 6% or more. Insulating materials that exhibit the above-mentioned compression characteristics during the compression and compression-release processes of the loading-unloading test 1 are preferably used as insulating materials placed between cells in battery modules, for example, and can vary in thickness accordingly in response to repeated expansion and contraction of the cells, and can also exhibit cushioning properties that can generate appropriate stress.
　いくつかの態様に係る断熱材は、上記載荷－除荷試験１の圧縮過程における圧力０．３４ＭＰａ時の圧縮ひずみが、４０％以下であることが適当であり、３５％以下であることが有利であり、３０％以下（例えば３０％未満）であることが好ましく、２５％以下、２０％以下または１５％以下であってもよい。かかる態様の断熱材において、上記圧力０．３４ＭＰａ時の圧縮ひずみは、典型的には０％超であり、３％以上であってもよく、５％以上または１０％以上であってもよい。また、上記態様に係る断熱材は、上記載荷－除荷試験１の圧縮過程における圧力３．４５ＭＰａ時の圧縮ひずみが、２０％以上であることが適当であり、２５％以上であることが好ましく、３０％以上（例えば３０％超）であることがより好ましく、３５％以上であってもよく、４０％以上であってもよい。かかる態様の断熱材において、上記圧力３．４５ＭＰａ時の圧縮ひずみは、例えば７０％以下であってよく、６５％以下または６０％以下（例えば６０％未満）であってもよい。載荷－除荷試験１の圧縮過程における圧力０．３４ＭＰａ時および圧力３．４５ＭＰａ時の圧縮ひずみがそれぞれ上記範囲にある断熱材によると、上述した好ましいひずみ差分（Ｘｈｐ）および／またはひずみ差分（Ｘｈｒ）が得られやすい。 In some embodiments of the insulating material, the compressive strain at a pressure of 0.34 MPa in the compression process of the above-described load-unload test 1 is suitably 40% or less, advantageously 35% or less, preferably 30% or less (e.g., less than 30%), and may be 25% or less, 20% or less, or 15% or less. In the insulating material of such an embodiment, the compressive strain at the above-described pressure of 0.34 MPa is typically more than 0%, and may be 3% or more, 5% or more, or 10% or more. In addition, in the insulating material of the above embodiment, the compressive strain at a pressure of 3.45 MPa in the compression process of the above-described load-unload test 1 is suitably 20% or more, preferably 25% or more, more preferably 30% or more (e.g., more than 30%), may be 35% or more, or may be 40% or more. In this embodiment of the insulating material, the compressive strain at a pressure of 3.45 MPa may be, for example, 70% or less, or 65% or less, or 60% or less (for example, less than 60%). With an insulating material in which the compressive strains at a pressure of 0.34 MPa and at a pressure of 3.45 MPa during the compression process of loading-unloading test 1 are within the above ranges, the above-mentioned preferable strain difference (Xhp) and/or strain difference (Xhr) are easily obtained.
　ここに開示される断熱材は、また、後述する実施例に記載の方法により行われる低圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験２）において、圧縮過程における圧力０．０３ＭＰａ時の圧縮ひずみを圧力１．３９ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｌｐ））が１５％以上（より好ましくは２０％以上または２５％以上、さらに好ましくは３０％以上）であり、かつ、圧縮解放過程において上記圧縮過程の圧縮応力０．０３ＭＰａと同一変位になる圧縮状態での圧縮ひずみを圧力１．３９ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｌｒ））が、５％以上（より好ましくは６％以上、さらに好ましくは８％以上または１０％以上）であることが好ましい。上記ひずみ差分（Ｘｌｐ）が３０％以上であり、かつ、上記ひずみ差分（Ｘｌｒ）が６％以上（さらに好ましくは８％以上、例えば１０％以上）であることがより好ましい。載荷－除荷試験２の圧縮過程および圧縮解放過程において上記のような圧縮特性を示す断熱材は、例えばバッテリーモジュール等においてセル間に配置される断熱材として好ましく用いられて、セルの膨張と収縮の繰り返し等に対して相応の厚みを変動でき、さらに適度な応力を発生しうる緩衝性を発揮し得る。 In the insulating material disclosed herein, in a loading-unloading test under low pressure conditions (i.e., loading-unloading test 2) performed by the method described in the examples below, the value obtained by subtracting the compressive strain at a pressure of 0.03 MPa during the compression process from the compressive strain at a pressure of 1.39 MPa (strain difference (Xlp)) is 15% or more (more preferably 20% or more or 25% or more, and even more preferably 30% or more), and the value obtained by subtracting the compressive strain in a compressed state that results in the same displacement as the compressive stress of 0.03 MPa during the compression process during the compression-release process from the compressive strain at a pressure of 1.39 MPa (strain difference (Xlr)) is 5% or more (more preferably 6% or more, and even more preferably 8% or more or 10% or more). It is more preferable that the strain difference (Xlp) is 30% or more, and the strain difference (Xlr) is 6% or more (even more preferably 8% or more, for example 10% or more). Insulating materials that exhibit the above-mentioned compression characteristics during the compression and compression-release processes of the loading-unloading test 2 are preferably used as insulating materials placed between cells in battery modules, for example, and can vary in thickness accordingly in response to repeated expansion and contraction of the cells, and can also exhibit cushioning properties that can generate appropriate stress.
　いくつかの態様に係る断熱材は、上記載荷－除荷試験２の圧縮過程における圧力０．０３ＭＰａ時の圧縮ひずみが、４０％以下であることが適当であり、３５％以下であることが有利であり、３０％以下（例えば３０％未満）であることが好ましく、２５％以下、２０％以下または１５％以下であってもよい。かかる態様の断熱材において、上記圧力０．０３ＭＰａ時の圧縮ひずみは、典型的には０％超であり、３％以上であってもよく、５％以上または１０％以上であってもよい。また、上記態様に係る断熱材は、上記載荷－除荷試験２の圧縮過程における圧力１．３９ＭＰａ時の圧縮ひずみが、２０％以上であることが適当であり、３０％以上（例えば３０％超）であることが好ましく、４０％以上であってもよく、５０％以上または５５％以上であってもよい。かかる態様の断熱材において、上記圧力１．３９ＭＰａ時の圧縮ひずみは、例えば９０％以下であってよく、８５％以下であってもよく、８０％以下、７０％以下または６０％以下（例えば６０％未満）であってもよい。載荷－除荷試験２の圧縮過程における圧力０．０３ＭＰａ時および圧力１．３９ＭＰａ時の圧縮ひずみがそれぞれ上記範囲にある断熱材によると、上述した好ましいひずみ差分（Ｘｌｐ）および／またはひずみ差分（Ｘｌｒ）が得られやすい。 In some embodiments of the insulating material, the compressive strain at a pressure of 0.03 MPa during the compression process of the above-described load-unload test 2 is suitably 40% or less, advantageously 35% or less, preferably 30% or less (e.g., less than 30%), and may be 25% or less, 20% or less, or 15% or less. In the insulating material of such an embodiment, the compressive strain at the above-described pressure of 0.03 MPa is typically more than 0%, and may be 3% or more, 5% or more, or 10% or more. In addition, in the insulating material of the above embodiment, the compressive strain at a pressure of 1.39 MPa during the compression process of the above-described load-unload test 2 is suitably 20% or more, preferably 30% or more (e.g., more than 30%), and may be 40% or more, 50% or more, or 55% or more. In the insulating material of this embodiment, the compressive strain at the pressure of 1.39 MPa may be, for example, 90% or less, 85% or less, 80% or less, 70% or less, or 60% or less (for example, less than 60%). With an insulating material in which the compressive strain at a pressure of 0.03 MPa and a pressure of 1.39 MPa during the compression process of loading-unloading test 2 is within the above ranges, the above-mentioned preferable strain difference (Xlp) and/or strain difference (Xlr) is easily obtained.
　ここに開示される断熱材の用途は、特に限定されず、断熱材が利用される公知の用途に適宜利用することができる。いくつかの態様に係る断熱材は、バッテリーモジュールのセル間に配置される断熱材として使用することが好ましく、より具体的にはリチウムイオンバッテリーモジュールのセル間に配置される断熱材として使用することが特に好ましい。 The uses of the insulating material disclosed herein are not particularly limited, and the material can be used appropriately in known applications for which insulating materials are used. The insulating material according to some embodiments is preferably used as an insulating material disposed between cells of a battery module, and more specifically, is particularly preferably used as an insulating material disposed between cells of a lithium-ion battery module.
　図２は、本発明の一態様である断熱材がセル間に配置されたバッテリーモジュールの一例を模式的に示す斜視図であり、図３はそのII－II線断面図である。図２に示されるように、バッテリーモジュール５０は、厚み方向に配列された複数の電池セル（ここでは角型セル）５１を備え、各電池セル５１同士の間に断熱材５２が配置されている。このように相互の間に断熱材５２を挟んで配列された複数の電池セル５１は、通常、両端に配置された拘束板５２ａ、５２ａを介して厚さ方向に押圧力（圧縮力）を加えた状態で拘束され、バッテリーケース５３に収容して用いられる。 FIG. 2 is a perspective view showing a schematic example of a battery module in which a heat insulating material, which is an embodiment of the present invention, is disposed between cells, and FIG. 3 is a cross-sectional view taken along line II-II thereof. As shown in FIG. 2, a battery module 50 comprises a plurality of battery cells (here rectangular cells) 51 arranged in the thickness direction, with heat insulating material 52 disposed between each battery cell 51. The plurality of battery cells 51 thus arranged with heat insulating material 52 sandwiched between them are typically restrained with a pressing force (compressive force) applied in the thickness direction via restraining plates 52a, 52a arranged at both ends, and are housed in a battery case 53 for use.
　図３に示されるように、断熱材５２は、断熱層５２１と緩衝層５２２とが積層されており、これらが２枚の樹脂フィルム（２層の被覆層）５２３Ａ，５２３Ｂにより厚み方向から挟まれて包設された構成を有する。樹脂フィルム５２３Ａ，５２３Ｂは、それらの外縁に沿って設けられたシール部において接着（例えば熱溶着）により密閉され、一体となって被覆材５２３を形成している。かかる構成の断熱材５２が隣接する２つの電池セル５１，５１の間に挟み込まれていることにより、上記２つの電池セル５１，５１の対向面５１ａ，５１ａ間を断熱する効果が発揮される。なお、図３には２つの緩衝層５２２Ａ，５２２Ｂが被覆材５２３内に積層配置された構成を示しているが、緩衝層の数は１つでもよく、２つ以上であってもよく、２以上の緩衝層が断熱層の両側に分けて配置されていてもよい。同様に、図３には１つの断熱層５２１のみを有する構成を示しているが、断熱層の数は２つ以上であってもよい。また、緩衝層は被覆材の外側に配置されていてもよく、複数の緩衝層が被覆材の外側と内側とに分けて配置されていてもよい。被覆材５２３には通気口が設けられていてもよい。 As shown in FIG. 3, the heat insulating material 52 has a structure in which a heat insulating layer 521 and a buffer layer 522 are laminated, and these are sandwiched and wrapped in two resin films (two coating layers) 523A, 523B from the thickness direction. The resin films 523A, 523B are sealed by adhesion (for example, heat welding) at the seal parts provided along their outer edges, and are integrated to form the coating material 523. The heat insulating material 52 having such a structure is sandwiched between two adjacent battery cells 51, 51, thereby exerting the effect of insulating the opposing surfaces 51a, 51a of the two battery cells 51, 51. Note that FIG. 3 shows a structure in which two buffer layers 522A, 522B are laminated in the coating material 523, but the number of buffer layers may be one or two or more, and two or more buffer layers may be arranged separately on both sides of the heat insulating layer. Similarly, FIG. 3 shows a structure having only one heat insulating layer 521, but the number of heat insulating layers may be two or more. The buffer layer may be disposed on the outside of the covering material, or multiple buffer layers may be disposed separately on the outside and inside of the covering material. The covering material 523 may be provided with an air vent.
　以下、断熱材のとり得るいくつかの態様について、より具体的に例示する。
　図４は、一実施形態に係る断熱材を模式的に示す斜視図であり、図５は図４のIV－IV線断面図である。断熱材１は、図５に示されるように、緩衝層２０の一方の面２０ａに、２つの断熱層１０Ａ，１０Ｂからなる断熱層１０が積層され、それらが２枚の樹脂フィルム（２層の被覆層）３１Ａ，３１Ｂにより厚み方向から挟まれて包設された構成を有する。樹脂フィルム３１Ａ，３１Ｂは、それらの外縁に沿って設けられたシール部３２において接着（例えば熱溶着）により密閉され、一体となって被覆材３０を形成している。樹脂フィルム３１Ａは、断熱層１０と緩衝層２０との積層物の端面を概ね覆う凸形状に成形されており、この端面を覆う部分に通気口（貫通孔）３３が形成されている。通気口３３の外部への開口部には、断熱層からの粉体流出を防ぐための通気膜３４が配置されている。この断熱材１は、例えば厚み方向に配列された複数のセルを備えるバッテリーモジュールにおいて上記セル間に配置される場合、図５に示すＺ方向（断熱材１の厚さ方向）が上記セルの配列方向となり、Ｙ方向が上記セルの電極取り出し方向となるように、すなわち断熱材１の通気口の開口方向（Ｘ方向）とセルの電極取り出し方向とが一致しない向きとなるように配置して用いられ得る。 Some possible embodiments of the heat insulating material will be described in more detail below.
FIG. 4 is a perspective view showing a typical heat insulating material according to one embodiment, and FIG. 5 is a cross-sectional view taken along line IV-IV in FIG. 4. As shown in FIG. 5, the heat insulating material 1 has a structure in which a heat insulating layer 10 consisting of two heat insulating layers 10A and 10B is laminated on one surface 20a of a buffer layer 20, and the heat insulating layer 10 is sandwiched and wrapped in two resin films (two coating layers) 31A and 31B in the thickness direction. The resin films 31A and 31B are sealed by adhesion (for example, heat welding) at a seal portion 32 provided along their outer edges, and integrally form a coating material 30. The resin film 31A is formed into a convex shape that generally covers the end face of the laminate of the heat insulating layer 10 and the buffer layer 20, and a vent (through hole) 33 is formed in the portion covering this end face. An air permeable film 34 is arranged at the opening of the air permeable film 33 to the outside to prevent powder from flowing out from the heat insulating layer. When this insulating material 1 is placed between cells in a battery module having a plurality of cells arranged in the thickness direction, for example, the Z direction (thickness direction of the insulating material 1) shown in Figure 5 is the arrangement direction of the cells, and the Y direction is the electrode extraction direction of the cells, that is, the opening direction of the air vent in the insulating material 1 (X direction) and the electrode extraction direction of the cells do not coincide.
　図６は、他の一実施形態に係る断熱材を模式的に示す断面図である。この実施形態では、断熱層１０を構成する２つの断熱層１０Ａ，１０Ｂが、緩衝層２０の一方の面２０ａおよび他方の面２０ｂに分けて積層されている。かかる構成の断熱材１は、厚さ方向に対して構造の対称性が高く、また両面の温度差を抑制しやすいことから、断熱材の変形（例えば反り変形）防止の観点から有利となり得る。なお、図７に示す実施形態例のように、緩衝層２０は、緩衝層２０Ａ，２０Ｂの２層からなる積層構造であってもよく、３層以上の積層構造であってもよい。また、断熱層１０Ａの内面１０ａと緩衝材２０とは、接合されていてもよく、接合されていなくてもよい。断熱層１０Ｂの内面と緩衝材２０との接合についても同様である。 FIG. 6 is a cross-sectional view showing a schematic of an insulating material according to another embodiment. In this embodiment, two insulating layers 10A and 10B constituting the insulating layer 10 are laminated on one side 20a and the other side 20b of the buffer layer 20. The insulating material 1 having such a configuration has a high structural symmetry in the thickness direction and is easy to suppress the temperature difference between the two sides, which may be advantageous from the viewpoint of preventing deformation (e.g., warping) of the insulating material. As in the embodiment shown in FIG. 7, the buffer layer 20 may have a laminated structure consisting of two layers of the buffer layers 20A and 20B, or a laminated structure of three or more layers. In addition, the inner surface 10a of the insulating layer 10A and the buffer material 20 may or may not be bonded. The same applies to the bonding between the inner surface of the insulating layer 10B and the buffer material 20.
　図８は、他の一実施形態に係る断熱材を模式的に示す断面図である。この実施形態では、断熱層１０が被覆材３０に包摂される一方、緩衝材２０は被覆材３０の外側に配置されている。より詳しくは、緩衝材２０の一方の面２０ａが、接着剤または粘着剤からなる接着層４０を介して被覆材３０の一方の面に固定されている。ここに開示される断熱材は、このような態様でも実施することができる。 FIG. 8 is a cross-sectional view showing a schematic of an insulating material according to another embodiment. In this embodiment, the insulating layer 10 is enclosed in the covering material 30, while the buffer material 20 is disposed outside the covering material 30. More specifically, one surface 20a of the buffer material 20 is fixed to one surface of the covering material 30 via an adhesive layer 40 made of an adhesive or pressure-sensitive adhesive. The insulating material disclosed herein can also be implemented in such an embodiment.
　なお、対象となるセルは、角型セルに限定されず、例えばラミネートセル、円筒型セルのいずれであってもよい。断熱材の形状は、セルの種類に応じて適宜採用することができる。 The target cells are not limited to rectangular cells, but may be, for example, laminated cells or cylindrical cells. The shape of the insulation material can be appropriately adopted depending on the type of cell.
　また、バッテリーの対象機器としては、電気自動車（ＥＶ）、ハイブリッド自動車（ＨＶ）、プラグインハイブリッド自動車（ＰＨＶ）等の電動車両、携帯端末、携帯電話およびノート型パソコン等の携帯電子機器、ウェアラブル機器等が挙げられる。 Devices that the batteries will be used on include electric vehicles such as electric vehicles (EVs), hybrid vehicles (HVs), and plug-in hybrid vehicles (PHVs), portable electronic devices such as mobile terminals, mobile phones, and notebook computers, and wearable devices.
（断熱材の製造方法）
　断熱材の製造方法は、特に限定されず、公知の工程を適宜採用して製造することができる。例えば、下記の工程を含む製造方法が挙げられる。
・断熱層準備工程：無機粒子を含んでなる断熱層を準備する工程
・緩衝層準備工程：繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層を準備する工程
・積層工程：断熱層準備工程で準備した断熱層および緩衝層準備工程で準備した緩衝層を含む構成層群を積層する工程 (Method of manufacturing heat insulating material)
The method for producing the insulating material is not particularly limited, and the insulating material can be produced by appropriately adopting known processes. For example, a production method including the following steps can be mentioned.
- Heat insulating layer preparation step: a step of preparing a heat insulating layer containing inorganic particles. - Buffer layer preparation step: a step of preparing a buffer layer made of a fiber molded body containing fibers or a foamed molded body containing a foam. - Lamination step: a step of laminating a group of constituent layers including the heat insulating layer prepared in the heat insulating layer preparation step and the buffer layer prepared in the buffer layer preparation step.
　なお、断熱層準備工程、緩衝層準備工程、積層工程は、先の工程を引用していないものであれば、時系列として、その他の工程と同時並行で行われる工程であってもよく、順番に行われる工程であってもよい。 In addition, the heat insulating layer preparation process, the buffer layer preparation process, and the lamination process may be processes that are performed simultaneously with other processes in a chronological order, or may be processes that are performed in sequence, as long as they do not refer to previous processes.
　いくつかの態様において、上記緩衝層準備工程は、緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、上述した領域（ｂ１）（好ましくは領域（ｂ２）、より好ましくは領域（ｂ３）、さらに好ましくは領域（ｂ４））を通過するか、または、上述した領域（ｂ５）（好ましくは領域（ｂ６）、より好ましくは領域（ｂ７）、さらに好ましくは領域（ｂ８））を通過する応力－ひずみ曲線を与える緩衝層を選択することを含み得る。したがって、この明細書によると、緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、ひずみをｘ軸、応力をｙ軸とするグラフにおいて所定の領域を通過する緩衝層を選択すること；および、無機粒子を含んでなる断熱層と上記緩衝層とを積層すること；を含む、断熱材の製造方法が提供される。 In some embodiments, the buffer layer preparation step may include selecting a buffer layer that, when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min, passes through the above-mentioned region (b1) (preferably region (b2), more preferably region (b3), and even more preferably region (b4)) or passes through the above-mentioned region (b5) (preferably region (b6), more preferably region (b7), and even more preferably region (b8)). Thus, according to this specification, a method for producing an insulating material is provided, which includes: selecting a buffer layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on the buffer layer alone at a compression speed of 0.5 mm/min; and laminating an insulating layer containing inorganic particles and the buffer layer.
　いくつかの好ましい態様において、上記断熱層準備工程は、断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、上述した領域（ａ１）（好ましくは領域（ａ２）、より好ましくは領域（ａ３））を通過するか、または、上述した領域（ａ４）（好ましくは領域（ａ５）、より好ましくは領域（ａ６））を通過する応力－ひずみ曲線を与える断熱層を選択することを含み得る。したがって、この明細書によると、緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、ひずみをｘ軸、応力をｙ軸とするグラフにおいて所定の領域を通過する緩衝層を選択すること；断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、ひずみをｘ軸、応力をｙ軸とするグラフにおいて所定の領域を通過する断熱層を選択すること；および、上記断熱層と上記緩衝層とを積層すること；を含む、断熱材の製造方法が提供される。また、上記緩衝層の選択および上記断熱層の選択を含む、断熱層の設計方法が提供される。 In some preferred embodiments, the heat insulating layer preparation step may include selecting a heat insulating layer that provides a stress-strain curve that passes through the above-mentioned region (a1) (preferably region (a2), more preferably region (a3)) or passes through the above-mentioned region (a4) (preferably region (a5), more preferably region (a6)) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min. Thus, according to this specification, a method for manufacturing a heat insulating material is provided, which includes: selecting a buffer layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min; selecting a heat insulating layer that passes through a predetermined region in a graph with strain on the x-axis and stress on the y-axis when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min; and laminating the heat insulating layer and the buffer layer. Also provided is a method for designing a heat insulating layer, which includes selecting the buffer layer and selecting the heat insulating layer.
　また、いくつかの態様において、上記緩衝層準備工程は、０．３４ＭＰａ圧縮時ひずみ、１．００ＭＰａ圧縮時ひずみ、１．３９ＭＰａ圧縮時ひずみおよび３．４５ＭＰａ圧縮時ひずみの少なくとも１つが、この明細書により開示されるいずれかの範囲にある緩衝層を選択することを含み得る。例えば、後述する高圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験１）において良好な圧縮特性を示す断熱材の製造または設計にあたっては、少なくとも０．３４ＭＰａ圧縮時ひずみおよび３．４５ＭＰａ圧縮時ひずみが、この明細書により開示されるいずれかの範囲にある緩衝層を選択することが好ましい。また、後述する低圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験２）において良好な圧縮特性を示す断熱材の製造または設計にあたっては、少なくとも０．３４ＭＰａ圧縮時ひずみおよび１．３９ＭＰａ圧縮時ひずみが、この明細書により開示されるいずれかの範囲にある緩衝層を選択することが好ましい。 In some embodiments, the buffer layer preparation step may include selecting a buffer layer in which at least one of the 0.34 MPa compressive strain, 1.00 MPa compressive strain, 1.39 MPa compressive strain, and 3.45 MPa compressive strain is within any of the ranges disclosed in this specification. For example, in manufacturing or designing a thermal insulation material that exhibits good compressive properties in a loading-unloading test under high pressure conditions (i.e., loading-unloading test 1) described below, it is preferable to select a buffer layer in which at least the 0.34 MPa compressive strain and the 3.45 MPa compressive strain are within any of the ranges disclosed in this specification. In addition, in manufacturing or designing a thermal insulation material that exhibits good compressive properties in a loading-unloading test under low pressure conditions (i.e., loading-unloading test 2) described below, it is preferable to select a buffer layer in which at least the 0.34 MPa compressive strain and the 1.39 MPa compressive strain are within any of the ranges disclosed in this specification.
　いくつかの態様において、上記断熱層準備工程は、０．３４ＭＰａ圧縮時ひずみ、１．００ＭＰａ圧縮時ひずみ、１．３９ＭＰａ圧縮時ひずみおよび３．４５ＭＰａ圧縮時ひずみの少なくとも１つが、この明細書により開示されるいずれかの範囲にある断熱層を選択することを含み得る。例えば、後述する高圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験１）において良好な圧縮特性を示す断熱材の製造または設計にあたっては、少なくとも０．３４ＭＰａ圧縮時ひずみおよび３．４５ＭＰａ圧縮時ひずみの値が、この明細書により開示されるいずれかの範囲にある断熱層を選択することが好ましい。また、後述する低圧力条件での載荷－除荷試験（すなわち、載荷－除荷試験２）において良好な圧縮特性を示す断熱材の製造または設計にあたっては、少なくとも０．３４ＭＰａ圧縮時ひずみおよび１．３９ＭＰａ圧縮時ひずみの値が、この明細書により開示されるいずれかの範囲にある断熱層を選択することが好ましい。いくつかの態様では、さらに、上述した０．３４ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）および１．３９ＭＰａ圧縮時ひずみ比（緩衝層／断熱層）を考慮して断熱材を製造または設計することがより好ましい。 In some embodiments, the insulating layer preparation step may include selecting an insulating layer in which at least one of the 0.34 MPa compressive strain, 1.00 MPa compressive strain, 1.39 MPa compressive strain, and 3.45 MPa compressive strain is within any of the ranges disclosed herein. For example, in manufacturing or designing an insulating material that exhibits good compressive properties in a loading-unloading test under high pressure conditions (i.e., loading-unloading test 1) described below, it is preferable to select an insulating layer in which the values of at least the 0.34 MPa compressive strain and the 3.45 MPa compressive strain are within any of the ranges disclosed herein. In addition, in manufacturing or designing an insulating material that exhibits good compressive properties in a loading-unloading test under low pressure conditions (i.e., loading-unloading test 2) described below, it is preferable to select an insulating layer in which the values of at least the 0.34 MPa compressive strain and the 1.39 MPa compressive strain are within any of the ranges disclosed herein. In some embodiments, it is more preferable to manufacture or design the insulation material taking into consideration the above-mentioned 0.34 MPa compression strain ratio (buffer layer/insulation layer) and 1.39 MPa compression strain ratio (buffer layer/insulation layer).
　以下、断熱層準備工程、緩衝層準備工程、積層工程の各工程について詳細に説明する。 The following describes in detail each of the steps of the insulation layer preparation process, the buffer layer preparation process, and the lamination process.
　断熱層準備工程における断熱層の準備方法は、特に限定されず、既存の断熱材を断熱層として入手してもよく、上記準備工程において断熱層を作製してもよい。なお、断熱層が無機粒子および無機繊維を含む混合物を成形した層である場合、湿式法、乾式法等の公知の混合方法を採用して混合することができる。湿式法による作製方法としては、例えば下記の工程を含む作製方法が挙げられる。
・混合工程：無機粒子と無機繊維とを溶媒中で混合して混合液を得る工程
・塗布工程：混合工程で得られた混合液を塗布して塗布膜を得る工程
・塗布膜成形工程：塗布工程で得られた塗布膜を成形して断熱層を得る工程 The method of preparing the heat insulating layer in the heat insulating layer preparation step is not particularly limited, and an existing heat insulating material may be obtained as the heat insulating layer, or the heat insulating layer may be prepared in the above preparation step. When the heat insulating layer is a layer formed by molding a mixture containing inorganic particles and inorganic fibers, it can be mixed by adopting a known mixing method such as a wet method or a dry method. As a preparation method using a wet method, for example, a preparation method including the following steps can be mentioned.
Mixing process: A process of mixing inorganic particles and inorganic fibers in a solvent to obtain a mixed liquid. Coating process: A process of applying the mixed liquid obtained in the mixing process to obtain a coating film. Coating film forming process: A process of forming the coating film obtained in the coating process to obtain a heat insulating layer.
　混合工程は、無機粒子と無機繊維とを溶媒中で混合して混合液を得る工程である。これはいわゆる湿式法であり、具体的には溶媒中で、無機粒子と無機繊維を混合して混合液（スラリー状態）を調製する工程である。混合工程における混合は、例えばディスパー、ラボプラストミル、トリミックス、プラネタリーミキサー、ニーダー等を使用することが挙げられる。 The mixing process is a process in which inorganic particles and inorganic fibers are mixed in a solvent to obtain a mixed liquid. This is a so-called wet method, and specifically, it is a process in which inorganic particles and inorganic fibers are mixed in a solvent to prepare a mixed liquid (slurry state). For example, a disper, a labo plasto mill, a trimix, a planetary mixer, a kneader, etc. can be used for mixing in the mixing process.
　溶媒の種類は、特に限定されず、例えばアルコール、アミド、水等のプロトン性溶媒、エステル、ケトン、ニトリル、エーテル等の非プロトン性溶媒等が挙げられる。 The type of solvent is not particularly limited, and examples include protic solvents such as alcohols, amides, and water, and aprotic solvents such as esters, ketones, nitriles, and ethers.
　溶媒の表面張力は、特に限定されず、例えば２０ｍＮ／ｍ～７３ｍＮ／ｍであり、好ましくは２１ｍＮ／ｍ以上、好ましくは５０ｍＮ／ｍ以下、より好ましくは４０ｍＮ／ｍ以下、さらに好ましくは３０ｍＮ／ｍ以下である。溶媒の表面張力が上記範囲内であると、断熱性および機械強度が良好になる。なお、溶媒の表面張力の測定方法は、リング法により測定することが挙げられる。 The surface tension of the solvent is not particularly limited, and is, for example, 20 mN/m to 73 mN/m, preferably 21 mN/m or more, preferably 50 mN/m or less, more preferably 40 mN/m or less, and even more preferably 30 mN/m or less. If the surface tension of the solvent is within the above range, the thermal insulation and mechanical strength will be good. The surface tension of the solvent can be measured by the ring method, for example.
　混合温度は、特に限定されず、例えば２０℃以上かつ溶媒の沸点以下であり、好ましくは２２℃以上であり、好ましくは５０℃以下、より好ましくは４０℃以下、さらに好ましくは３０℃以下である。混合温度が上記範囲内であると、溶媒（例えば有機溶媒）が揮発しにくく、配合比が変化しにくくなる。 The mixing temperature is not particularly limited, and is, for example, 20°C or higher and the boiling point of the solvent or lower, preferably 22°C or higher, and preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower. If the mixing temperature is within the above range, the solvent (e.g., organic solvent) is less likely to volatilize, and the blending ratio is less likely to change.
　混合時間は、特に限定されず、例えば１分～５時間であり、好ましくは５分以上、好ましくは４時間以下、より好ましくは２時間以下であり、さらに好ましくは１時間以下である。混合時間が上記範囲内であると、効率よく断熱材を作製可能になる。 The mixing time is not particularly limited, and is, for example, 1 minute to 5 hours, preferably 5 minutes or more, preferably 4 hours or less, more preferably 2 hours or less, and even more preferably 1 hour or less. If the mixing time is within the above range, the insulating material can be produced efficiently.
　混合液のちょう度（稠度）は、特に限定されず、例えば５０～２００であり、好ましくは５５以上、より好ましくは６０以上であり、さらに好ましくは６５以上であり、好ましくは１８０以下、より好ましくは１６０以下、さらに好ましくは１４０以下である。混合液のちょう度が上記範囲内であると、繊維を均一分散させる際に繊維折れを低減できる。 The consistency (constancy) of the mixed liquid is not particularly limited, and is, for example, 50 to 200, preferably 55 or more, more preferably 60 or more, even more preferably 65 or more, and preferably 180 or less, more preferably 160 or less, and even more preferably 140 or less. If the consistency of the mixed liquid is within the above range, fiber breakage can be reduced when the fibers are uniformly dispersed.
　なお、混合液のちょう度の測定方法としては、日本産業規格ＪＩＳ Ｋ ２２２０：２０１３「グリース－第７部：ちょう度試験方法」に記載の方法が挙げられ、特に「不混和ちょう度」として測定することが挙げられる。ちょう度を測定することができる測定機器は、市販されており、具体的には日化エンジニアリング製ＰＥＮＥＴＲＯ ＭＥＴＥＲ等が挙げられる。測定手順としては、円錐の分銅を降下させたときに分銅が接触しない程度の大きさのつぼを準備し、それに混合液を充填して、分銅が取り付けられた測定機器に配置する。次に分銅の位置を調節して、分銅と混合液が接触する位置に設定し、その位置を０点とする。そして、室温（２５℃）の条件下で、分銅を５秒間（±０．１秒）降下させて、混合液に侵入した分銅の深さ（ｍｍ）×１０をちょう度として算出する。なお、円錐の分銅は、日本産業規格に規定されている標準円錐を使用することが挙げられ、分銅の全質量は１０２．５ｇ±０．０５ｇ、分銅の保持具の質量は、４７．５±０．０５ｇのものを使用することが挙げられる。 The method for measuring the consistency of the mixed liquid is as described in the Japanese Industrial Standard JIS K 2220:2013 "Grease - Part 7: Consistency test method", and in particular, the consistency can be measured as "immiscible consistency". Measuring instruments that can measure consistency are commercially available, and a specific example is the PENETRO METER manufactured by Nikka Engineering. The measurement procedure involves preparing a container large enough that the conical weight will not come into contact with the container when it is lowered, filling it with the mixed liquid, and placing it on the measuring instrument to which the weight is attached. Next, the position of the weight is adjusted so that it is in contact with the mixed liquid, and this position is designated as the zero point. Then, under room temperature (25°C) conditions, the weight is lowered for 5 seconds (±0.1 seconds), and the depth (mm) of the weight that has penetrated into the mixed liquid x 10 is calculated as the consistency. The conical weight should be a standard cone as specified in the Japanese Industrial Standards, with a total weight of 102.5g ± 0.05g and a weight holder with a weight of 47.5 ± 0.05g.
　塗布工程における塗布方法および塗布条件は、特に限定されず、公知の方法を適宜採用することができる。、例えば、コンマコータ、スピンコータ、ダイコータ、ディスペンサー等を使用して塗布することができる。 The coating method and conditions in the coating process are not particularly limited, and any known method can be used as appropriate. For example, coating can be done using a comma coater, spin coater, die coater, dispenser, etc.
　塗布膜成形工程における成形方法および成形条件は、特に限定されず、公知の方法を適宜採用することができる。例えば熱プレス、真空プレスを使用して圧縮成形し、例えば、フローティングオーブン、ＩＲオーブン等を使用して乾燥することが挙げられる。乾燥条件として、乾燥温度は、例えば、６０℃～１５０℃が好ましい。乾燥時間は、例えば、４分～２０分が好ましい。上記成形方法および成形条件は、所望の密度の（例えば、密度０．２～０．５ｇ／ｃｍ３の）断熱層が得られるように選択することができる。 The molding method and molding conditions in the coating film molding step are not particularly limited, and known methods can be appropriately adopted. For example, compression molding using a heat press or a vacuum press, and drying using a floating oven, an IR oven, or the like can be mentioned. As drying conditions, the drying temperature is preferably, for example, 60°C to 150°C. The drying time is preferably, for example, 4 minutes to 20 minutes. The above molding method and molding conditions can be selected so as to obtain a heat insulating layer with a desired density (for example, a density of 0.2 to 0.5 g/ cm3 ).
　緩衝層準備工程における緩衝層の準備方法は、特に限定されず、既存の断熱材等を緩衝層として入手してもよく、上記準備工程において緩衝層を作製してもよい。なお、緩衝層が繊維およびバインダーを含む混合物を成形した繊維成形体である場合の作製方法としては、例えば下記の工程を含む作製方法が挙げられる。
・前駆体準備工程：繊維にバインダーが分散した前駆体を準備する工程
・前駆体成形工程：前駆体準備工程で準備した前駆体を成形して緩衝層を得る工程 The method for preparing the buffer layer in the buffer layer preparation step is not particularly limited, and an existing heat insulating material or the like may be obtained as the buffer layer, or the buffer layer may be prepared in the above preparation step. In addition, when the buffer layer is a fiber molded body obtained by molding a mixture containing fibers and a binder, for example, a preparation method including the following steps may be mentioned.
Precursor preparation step: A step of preparing a precursor in which a binder is dispersed in fibers. Precursor molding step: A step of molding the precursor prepared in the precursor preparation step to obtain a buffer layer.
　前駆体成形工程における前駆体としては、繊維にバインダーとして熱硬化性樹脂が分散された状態で販売されているものがあり、それを入手することが挙げられる。 As for the precursor for the precursor molding process, there are some that are sold in a state where a thermosetting resin is dispersed in the fibers as a binder, and these can be obtained.
　前駆体成形工程における前駆体の成形方法は、特に限定されないが、前駆体を熱プレス機で加熱圧縮する方法が挙げられる。 The method for forming the precursor in the precursor forming process is not particularly limited, but examples include a method in which the precursor is heated and compressed using a heat press.
　積層工程における構成層群を積層する方法は、特に限定されず、構成層群を単に積み重ねてもよく、公知の圧縮成形方法とその条件を適宜採用して圧縮してもよく、隣接する層同士を接着剤または粘着剤により接合してもよい。また、２層以上の被覆層を使用し、それらの被覆層の間隙を密閉する場合には、被覆層同士を貼り合せることも積層工程に含まれる。 The method of laminating the constituent layers in the lamination process is not particularly limited, and the constituent layers may simply be stacked, or may be compressed using a known compression molding method and appropriate conditions, or adjacent layers may be bonded together with an adhesive or pressure sensitive adhesive. In addition, when two or more coating layers are used and the gaps between the coating layers are sealed, bonding the coating layers together is also included in the lamination process.
　この明細書により開示される事項には、以下のものが含まれる。
　〔１〕　無機粒子を含んでなる断熱層と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層と、を有する断熱材であって、
　前記緩衝層が、前記緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ１－１）および下記式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、断熱材。
　式（ｂ１－１）：０．５０≦ｙＢ≦３．４５
　式（ｂ１－２）：０．３０ｘＢ－１８．６８≦ｙＢ≦０．２０ｘＢ－０．４８
　〔２〕　前記断熱層が、前記断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ１－１）および下記式（ａ１－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１〕に記載の断熱材。
　式（ａ１－１）：０．５０≦ｙＡ≦３．４５
　式（ａ１－２）：０．１２ｘＡ－２．４５≦ｙＡ
　〔３〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ２－１）および下記式（ｂ２－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１〕または〔２〕に記載の断熱材。
　式（ｂ２－１）：１．００≦ｙＢ≦３．００
　式（ｂ２－２）：０．２０ｘＢ－１１．００≦ｙＢ≦０．１０ｘＢ
　〔４〕　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ２－１）および下記式（ａ２－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１〕～〔３〕のいずれかに記載の断熱材。
　式（ａ２－１）：１．００≦ｙＡ≦３．００
　式（ａ２－２）：０．２０ｘＡ－３．００≦ｙＡ
　〔５〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ３－１）および下記式（ｂ３－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１〕～〔４〕のいずれかに記載の断熱材。
　式（ｂ３－１）：１．５０≦ｙＢ≦３．００
　式（ｂ３－２）：０．１５ｘＢ－７．５０≦ｙＢ≦０．１０ｘＢ－１．００
　〔６〕　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ３－１）および下記式（ａ３－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１〕～〔５〕のいずれかに記載の断熱材。
　式（ａ３－１）：１．５０≦ｙＡ≦２．５０
　式（ａ３－２）：０．２０ｘＡ－１．５０≦ｙＡ
　〔７〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ４－１）および下記式（ｂ４－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じる層である、上記〔１〕～〔６〕のいずれかに記載の断熱材。
　式（ｂ４－１）：２．００≦ｙＢ≦２．５０
　式（ｂ４－２）：０．１０ｘＢ－３．５０≦ｙＢ≦０．１０ｘＢ－１．５０
　〔８〕　前記断熱層の前記無機粒子が、二酸化ケイ素粒子である、上記〔１〕～〔７〕のいずれかに記載の断熱材。
　〔９〕　前記二酸化ケイ素粒子が、乾式シリカ、湿式シリカ、およびシリカエアロゲルからなる群より選択される少なくとも１種である、上記〔１〕～〔８〕のいずれかに記載の断熱材。
　〔１０〕　前記二酸化ケイ素粒子が、親水性フュームドシリカである、上記〔１〕～〔９〕のいずれかに記載の断熱材。
　〔１１〕　前記断熱層が、無機粒子および無機繊維を含む混合物を成形した成形体である、上記〔１〕～〔１０〕のいずれかに記載の断熱材。
　〔１２〕　バッテリーモジュールまたはバッテリーパックのセル間に配置される、上記〔１〕～〔１１〕のいずれかに記載の断熱材。 The matters disclosed in this specification include the following.
[1] A heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foamed molded body containing a foam,
The thermal insulation material is a layer in which, when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min, a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) can be generated.
Formula (b1-1): 0.50≦y B ≦3.45
Formula (b1-2): 0.30x B -18.68≦y B ≦0.20x B -0.48
[2] The heat insulating material according to the above [1], wherein the heat insulating layer is a layer capable of generating a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a1-1) and (a1-2) when a compression test is performed on the heat insulating layer alone at a compression speed of 0.5 mm/min.
Formula (a1-1): 0.50≦y A ≦3.45
Formula (a1-2): 0.12x A -2.45≦y A
[3] The thermal insulation material according to the above [1] or [2], wherein the buffer layer is a layer that can generate a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b2-1) and (b2-2) when the compression test is performed.
Formula (b2-1): 1.00≦y B ≦3.00
Formula (b2-2): 0.20x B -11.00 ≦ y B ≦ 0.10x B
[4] The heat insulating material according to any one of [1] to [3] above, wherein the heat insulating layer is a layer that can generate a compressed state having a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a2-1) and formula (a2-2) when the compression test is performed.
Formula (a2-1): 1.00≦y A ≦3.00
Formula (a2-2): 0.20xA -3.00≦ yA
[5] The thermal insulation material according to any one of the above [1] to [4], wherein the buffer layer is a layer that can generate a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b3-1) and formula (b3-2) when the compression test is performed.
Formula (b3-1): 1.50≦y B ≦3.00
Formula (b3-2): 0.15x B -7.50≦y B ≦0.10x B -1.00
[6] The heat insulating material according to any one of [1] to [5] above, wherein the heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a3-1) and formula (a3-2) when the compression test is performed.
Formula (a3-1): 1.50≦y A ≦2.50
Formula (a3-2): 0.20xA -1.50≦ yA
[7] The thermal insulation material according to any one of the above [1] to [6], wherein the buffer layer is a layer that, when the compression test is performed, generates a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b4-1) and formula (b4-2):
Formula (b4-1): 2.00≦y B ≦2.50
Formula (b4-2): 0.10x B -3.50≦y B ≦0.10x B -1.50
[8] The heat insulating material according to any one of [1] to [7] above, wherein the inorganic particles of the heat insulating layer are silicon dioxide particles.
[9] The heat insulating material according to any one of [1] to [8] above, wherein the silicon dioxide particles are at least one selected from the group consisting of dry silica, wet silica, and silica aerogel.
[10] The heat insulating material according to any one of [1] to [9] above, wherein the silicon dioxide particles are hydrophilic fumed silica.
[11] The heat insulating material according to any one of the above [1] to [10], wherein the heat insulating layer is a molded body obtained by molding a mixture containing inorganic particles and inorganic fibers.
[12] The heat insulating material according to any one of [1] to [11] above, which is disposed between cells of a battery module or a battery pack.
　〔１３〕　無機粒子を含んでなる断熱層と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層と、を有する断熱材であって、
　前記緩衝層が、前記緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ５－１）および下記式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、断熱材。
　式（ｂ５－１）：０．１０≦ｙＢ≦１．３９
　式（ｂ５－２）：０．１２９ｘＢ－９．５７５≦ｙＢ≦０．１２９ｘＢ－１．１９
　〔１４〕　前記断熱層が、前記断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ４－１）および下記式（ａ４－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１３〕に記載の断熱材。
　式（ａ４－１）：０．１０≦ｙＡ≦１．３９
　式（ａ４－２）：０．０４３ｘＡ－０．５４５≦ｙＡ
　〔１５〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ６－１）および下記式（ｂ６－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１３〕または〔１４〕に記載の断熱材。
　式（ｂ６－１）：０．２０≦ｙＢ≦１．１０
　式（ｂ６－２）：０．１２ｘＢ－８．８０≦ｙＢ≦０．０３６ｘＢ－０．３４
　〔１６〕　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ５－１）および下記式（ａ５－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１３〕～〔１５〕のいずれかに記載の断熱材。
　式（ａ５－１）：０．２０≦ｙＡ≦１．１０
　式（ａ５－２）：０．０９ｘＡ－１．１５≦ｙＡ
　〔１７〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ７－１）および下記式（ｂ７－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１３〕～〔１６〕のいずれかに記載の断熱材。
　式（ｂ７－１）：０．３０≦ｙＢ≦０．９０
　式（ｂ７－２）：０．１２ｘＢ－８．７０≦ｙＢ≦０．０４ｘＢ－０．９０
　〔１８〕　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ６－１）および下記式（ａ６－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、上記〔１３〕～〔１７〕のいずれかに記載の断熱材。
　式（ａ６－１）：０．３０≦ｙＡ≦０．９０
　式（ａ６－２）：０．１２ｘＡ－０．９０≦ｙＡ
　〔１９〕　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ８－１）および下記式（ｂ８－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じる層である、上記〔１３〕～〔１８〕のいずれかに記載の断熱材。
　式（ｂ８－１）：０．４０≦ｙＢ≦０．８０
　式（ｂ８－２）：０．０８ｘＢ－５．６０≦ｙＢ≦０．０３２ｘＢ－０．８８
　〔２０〕　前記断熱層の前記無機粒子が、二酸化ケイ素粒子である、上記〔１３〕～〔１９〕のいずれかに記載の断熱材。
　〔２１〕　前記二酸化ケイ素粒子が、乾式シリカ、湿式シリカ、およびシリカエアロゲルからなる群より選択される少なくとも１種である、上記〔１３〕～〔２０〕のいずれかに記載の断熱材。
　〔２２〕　前記二酸化ケイ素粒子が、親水性フュームドシリカである、上記〔１３〕～〔２１〕のいずれかに記載の断熱材。
　〔２３〕　前記断熱層が、無機粒子および無機繊維を含む混合物を成形した成形体である、上記〔１３〕～〔２２〕のいずれかに記載の断熱材。
　〔２４〕　バッテリーモジュールまたはバッテリーパックのセル間に配置される、上記〔１３〕～〔２３〕のいずれかに記載の断熱材。 [13] A heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam,
The thermal insulation material is a layer in which a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) can be generated when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min.
Formula (b5-1): 0.10≦y B ≦1.39
Formula (b5-2): 0.129x B -9.575≦y B ≦0.129x B -1.19
[14] The heat insulating material according to [13] above, wherein the heat insulating layer is a layer that can produce a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formulae (a4-1) and (a4-2) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min.
Formula (a4-1): 0.10≦y A ≦1.39
Formula (a4-2): 0.043x A -0.545≦y A
[15] The thermal insulation material according to the above [13] or [14], wherein the buffer layer is a layer that can generate a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b6-1) and (b6-2) when the compression test is performed.
Formula (b6-1): 0.20≦y B ≦1.10
Formula (b6-2): 0.12x B -8.80≦y B ≦0.036x B -0.34
[16] The heat insulating material according to any one of [13] to [15] above, wherein the heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a5-1) and formula (a5-2) when the compression test is performed.
Formula (a5-1): 0.20≦y A ≦1.10
Formula (a5-2): 0.09x A −1.15≦y A
[17] The thermal insulation material according to any one of [13] to [16] above, wherein the buffer layer is a layer that can generate a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b7-1) and formula (b7-2) when the compression test is performed.
Formula (b7-1): 0.30≦y B ≦0.90
Formula (b7-2): 0.12x B -8.70≦y B ≦0.04x B -0.90
[18] The heat insulating material according to any one of [13] to [17] above, wherein the heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a6-1) and formula (a6-2) when the compression test is performed.
Formula (a6-1): 0.30≦y A ≦0.90
Formula (a6-2): 0.12x A −0.90≦y A
[19] The thermal insulation material according to any one of [13] to [18] above, wherein the buffer layer is a layer that, when the compression test is performed, generates a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b8-1) and formula (b8-2):
Formula (b8-1): 0.40≦y B ≦0.80
Formula (b8-2): 0.08x B -5.60≦y B ≦0.032x B -0.88
[20] The heat insulating material according to any one of [13] to [19] above, wherein the inorganic particles of the heat insulating layer are silicon dioxide particles.
[21] The heat insulating material according to any one of [13] to [20] above, wherein the silicon dioxide particles are at least one selected from the group consisting of dry silica, wet silica, and silica aerogel.
[22] The heat insulating material according to any one of [13] to [21] above, wherein the silicon dioxide particles are hydrophilic fumed silica.
[23] The heat insulating material according to any one of [13] to [22] above, wherein the heat insulating layer is a molded body obtained by molding a mixture containing inorganic particles and inorganic fibers.
[24] The heat insulating material according to any one of [13] to [23] above, which is disposed between cells of a battery module or a battery pack.
　以下、本発明に関するいくつかの実施例を説明するが、本発明をかかる具体例に示すものに限定する意図ではない。 Below, several examples of the present invention are described, but it is not intended that the present invention be limited to these specific examples.
＜断熱材（断熱層Ａ）の製造＞
　親水性フュームドシリカ粒子（「ＡＥＲＯＳＩＬ（登録商標）　３８０」、日本アエロジル社製、平均一次粒子径：約７ｎｍ、ＢＥＴ比表面積：３８０ｍ２／ｇ）２１質量部と、無機繊維であるガラス繊維（「ＣＳ　２５Ｋ－８７１」、日東紡績社製、平均繊維径：１３μｍ、平均繊維長：２５ｍｍ）４質量部を事前に手でほぐして繊維を開繊したものとを、ビニール袋に入れて均一に分散するように混合した。次に、得られた混合粉体を紙、不織布、布、織物でできた通気性の良い袋に投入し、中身の粉体を押し固めた成形物の密度が０．２５ｇ／ｃｍ３のシート状になるようにプレス機で圧縮成形して、親水性フュームドシリカ、ガラス繊維を含有する混合物を成形した成形体である断熱材（断熱層Ａ）を作製した。得られた断熱材（断熱層Ａ）の厚さは２ｍｍであり、密度は０．２３ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer A)>
21 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 380", manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter: about 7 nm, BET specific surface area: 380 m 2 /g) and 4 parts by mass of inorganic glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd., average fiber diameter: 13 μm, average fiber length: 25 mm) were mixed in a plastic bag so as to be uniformly dispersed, with the fibers being loosened by hand in advance. Next, the obtained mixed powder was put into a breathable bag made of paper, nonwoven fabric, cloth, or woven fabric, and the powder inside was compressed and molded into a sheet-like shape with a density of 0.25 g/cm 3 , to produce a thermal insulation material (thermal insulation layer A) which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber. The thickness of the obtained thermal insulation material (thermal insulation layer A) was 2 mm, and the density was 0.23 g/cm 3 .
＜断熱材（断熱層Ｂ）の製造＞
　プロトン性溶媒である酢酸（表面張力：２７ｍＮ／ｍ）８３質量部と水（表面張力：７３ｍＮ／ｍ）１７質量部との混合溶媒（表面張力：３３ｍＮ／ｍ）に対して、親水性フュームドシリカ粒子（「ＡＥＲＯＳＩＬ（登録商標）　２００」、日本アエロジル社製）２１質量部と、ガラス繊維（「ＣＳ　２５Ｋ－８７１」、日東紡績社製）４質量部とを加え、後述する方法により測定されるちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが４ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ２ｍｍで密度が０．１～０．３ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカおよびガラス繊維を含有する混合物を成形した成形体である断熱材（断熱層Ｂ）を作製した。得られた断熱材（断熱層Ｂ）の厚さは２ｍｍであり、密度は０．３３ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer B)>
To a mixed solvent (surface tension: 33 mN/m) of 83 parts by mass of acetic acid (surface tension: 27 mN/m) which is a protic solvent and 17 parts by mass of water (surface tension: 73 mN/m), 21 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.) and 4 parts by mass of glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency measured by the method described below was 70 to 140. Next, the resulting mixed liquid was applied to a substrate so as to have a thickness of 4 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 2 mm and a density of 0.1 to 0.3 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer B) which is a molded body formed by molding a mixture containing hydrophilic fumed silica and glass fiber. The resulting heat insulating material (heat insulating layer B) had a thickness of 2 mm and a density of 0.33 g/cm 3 .
＜断熱材（断熱層Ｃ）の製造＞
　酢酸８３質量部と水１７質量部の混合溶媒（表面張力：３３ｍＮ／ｍ）に対して、親水性フュームドシリカ粒子（「ＡＥＲＯＳＩＬ（登録商標）　２００」、日本アエロジル社製）２１質量部と、ガラス繊維（「ＣＳ　２５Ｋ－８７１」、日東紡績社製）４質量部とを加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが４ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ２ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカおよびガラス繊維を含有する混合物を成形した成形体である断熱材（断熱層Ｃ）を作製した。得られた断熱材（断熱層Ｃ）の厚さは２ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer C)>
To a mixed solvent (surface tension: 33 mN/m) of 83 parts by mass of acetic acid and 17 parts by mass of water, 21 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.) and 4 parts by mass of glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency was 70 to 140. Next, the resulting mixture was applied to a substrate so as to have a thickness of 4 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 2 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer C) which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber. The thickness of the obtained heat insulating material (heat insulating layer C) was 2 mm and the density was 0.37 g/cm 3 .
＜断熱材（断熱層Ｄ）の製造＞
　プロトン性溶媒であるイソプロピルアルコール（ＩＰＡ、表面張力：２１ｍＮ／ｍ）３００質量部と水６０質量部との混合溶媒（表面張力：２３ｍＮ／ｍ）に対して、親水性フュームドシリカ粒子（「ＡＥＲＯＳＩＬ（登録商標）２００」、日本アエロジル社製）１００質量部と、ガラス繊維（「ＣＳ　６Ｊ－８８８」、日東紡績社製、平均繊維径：１１μｍ、平均繊維長：６ｍｍ）２０質量部と、非高分子型分散剤として花王社製コータミン２４Ｐ（有効成分：塩化ドデシルトリメチルアンモニウム（Ｃ１２Ｈ２５Ｎ＋（ＣＨ３）３Ｃｌ））、有効成分含有率：２７質量％）１．９質量部（有効成分（アンモニウム塩）として０．５質量部）を加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが４ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ２ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカ、ガラス繊維、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層Ｄ）を作製した。得られた断熱材（断熱層Ｄ）の厚さは２ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer D)>
To a mixed solvent (surface tension: 23 mN/m) of 300 parts by mass of isopropyl alcohol (IPA, surface tension: 21 mN/m) as a protic solvent and 60 parts by mass of water, 100 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.), 20 parts by mass of glass fiber ("CS 6J-888", manufactured by Nitto Boseki Co., Ltd., average fiber diameter: 11 μm, average fiber length: 6 mm), and 1.9 parts by mass of Kao Corporation's Kotamin 24P (active ingredient: dodecyltrimethylammonium chloride (C 12 H 25 N + (CH 3 ) 3 Cl), active ingredient content: 27% by mass) as a non-polymeric dispersant (0.5 parts by mass as active ingredient (ammonium salt)) were added and mixed to a consistency of 70 to 140. Next, the resulting mixed solution was applied to a substrate to a thickness of 4 mm to form a coating film. Furthermore, the coating film was compression molded in a hot press into a sheet having a thickness of 2 mm and a density of 0.3 to 0.5 g/ cm3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer D) which is a molded product of a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer D) had a thickness of 2 mm and a density of 0.37 g/ cm3 .
＜断熱材（断熱層Ｅ）の製造＞
　断熱層Ｄと同様の製造方法で厚さ２．１ｍｍ、密度０．３７ｇ／ｃｍ３のシートを作製した後、そのシートを圧縮速度０．５ｍｍ／ｓｅｃの速度で２．１ＭＰａの圧力となるまで載荷した後に圧力０ＭＰａとなるまで除荷する、という追加の加圧加工工程を１０回繰り返し行うことで、親水性フュームドシリカ、ガラス繊維、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層Ｅ）を作製した。得られた断熱材（断熱層Ｅ）の厚さは２ｍｍであり、密度は０．４０ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer E)>
A sheet having a thickness of 2.1 mm and a density of 0.37 g/ cm3 was produced by the same manufacturing method as for the insulating layer D, and then the sheet was loaded at a compression speed of 0.5 mm/sec until a pressure of 2.1 MPa was reached, and then unloaded until the pressure reached 0 MPa. This additional pressurizing process was repeated 10 times to produce an insulating material (insulating layer E) that was a molded body made by molding a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained insulating material (insulating layer E) had a thickness of 2 mm and a density of 0.40 g/ cm3 .
＜断熱材（断熱層Ｆ）の製造＞
　酢酸８３質量部と水１７質量部との混合溶媒（表面張力：３３ｍＮ／ｍ）に対して、親水性フュームドシリカ粒子（「ＡＥＲＯＳＩＬ（登録商標）　２００」、日本アエロジル社製）２１質量部と、ガラス繊維（「ＣＳ　２５Ｋ－８７１」、日東紡績社製）４質量部とを加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが２ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ１ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカおよびガラス繊維を含有する混合物を成形した成形体である断熱材（断熱層Ｆ）を作製した。得られた断熱材（断熱層Ｆ）の厚さは１ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Manufacture of heat insulating material (heat insulating layer F)>
To a mixed solvent (surface tension: 33 mN/m) of 83 parts by mass of acetic acid and 17 parts by mass of water, 21 parts by mass of hydrophilic fumed silica particles ("AEROSIL (registered trademark) 200", manufactured by Nippon Aerosil Co., Ltd.) and 4 parts by mass of glass fiber ("CS 25K-871", manufactured by Nitto Boseki Co., Ltd.) were added and mixed so that the consistency was 70 to 140. Next, the resulting mixture was applied to a substrate so as to have a thickness of 2 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine so as to have a sheet shape with a thickness of 1 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100 ° C. for 10 minutes to produce a heat insulating material (heat insulating layer F) which is a molded body formed from a mixture containing hydrophilic fumed silica and glass fiber. The obtained heat insulating material (heat insulating layer F) had a thickness of 1 mm and a density of 0.37 g/cm 3 .
＜断熱材（断熱層Ｇ）の製造＞
　断熱層Ｆと同様の製造方法で厚さ１．１ｍｍ、密度０．３７ｇ／ｃｍ３のシートを作製した後、そのシートを圧縮速度０．５ｍｍ／ｓｅｃの速度で１．３９ＭＰａの圧力となるまで載荷した後に圧力０ＭＰaとなるまで除荷する、という追加の加圧加工工程を１０回繰り返し行うことで、親水性フュームドシリカおよびガラス繊維を含有する混合物を成形した成形体である断熱材（断熱層Ｇ）を作製した。得られた断熱材（断熱層Ｇ）の厚さは１ｍｍであり、密度は０．４０ｇ／ｃｍ３であった。 <Manufacture of heat insulating material (heat insulating layer G)>
A sheet having a thickness of 1.1 mm and a density of 0.37 g/ cm3 was produced by the same manufacturing method as for the insulating layer F, and then the sheet was loaded at a compression speed of 0.5 mm/sec until a pressure of 1.39 MPa was reached, and then unloaded until the pressure reached 0 MPa. This additional pressurizing process was repeated 10 times to produce an insulating material (insulating layer G) that was a molded body made from a mixture containing hydrophilic fumed silica and glass fiber. The obtained insulating material (insulating layer G) had a thickness of 1 mm and a density of 0.40 g/ cm3 .
＜断熱材（断熱層Ｈ）の製造＞
　断熱層Ｄと同様の材料を加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが３．６ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ１．８ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカ、ガラス繊維、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層Ｈ）を作製した。得られた断熱材（断熱層Ｈ）の厚さは１．８ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Manufacture of heat insulating material (heat insulating layer H)>
The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to obtain a thickness of 3.6 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to obtain a sheet-like film having a thickness of 1.8 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100° C. for 10 minutes to produce a heat insulating material (heat insulating layer H) that is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer H) had a thickness of 1.8 mm and a density of 0.37 g/cm 3 .
＜断熱材（断熱層Ｉ）の製造＞
　断熱層Ｄと同様の材料を加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが１．６ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ０．８ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカ、ガラス繊維、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層I）を作製した。得られた断熱材（断熱層I）の厚さは０．８ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Production of heat insulating material (heat insulating layer I)>
The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to a thickness of 1.6 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 0.8 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer I) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer I) had a thickness of 0.8 mm and a density of 0.37 g/cm 3 .
＜断熱材（断熱層Ｊ）の製造＞
　断熱層Ｄと同様の材料を加え、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが２．４ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ１．２ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカ、ガラス繊維、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層Ｊ）を作製した。得られた断熱材（断熱層Ｊ）の厚さは１．２ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Manufacture of heat insulating material (heat insulating layer J)>
The same materials as those of the heat insulating layer D were added and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to the substrate to a thickness of 2.4 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 1.2 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce a heat insulating material (heat insulating layer J) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, and a non-polymeric dispersant. The obtained heat insulating material (heat insulating layer J) had a thickness of 1.2 mm and a density of 0.37 g/cm 3 .
＜断熱材（断熱層Ｋ）の製造＞
　断熱材Ｄの配合に黒鉛（「ＡＧＢ－５」、伊藤黒鉛工業社製、平均粒径５μｍ）１０質量部添加し、ちょう度が７０～１４０となるように混合した。次に、得られた混合液を、厚さが２．０ｍｍになるように基材に塗布して塗布膜を形成した。さらに、塗布膜が厚さ１．０ｍｍで密度が０．３～０．５ｇ／ｃｍ３のシート状になるように熱プレス機で圧縮成形した後、１００℃、１０分間乾燥して、親水性フュームドシリカ、ガラス繊維、黒鉛、および非高分子型分散剤を含有する混合物を成形した成形体である断熱材（断熱層Ｋ）を作製した。得られた断熱材（断熱層Ｋ）の厚さは１．０ｍｍであり、密度は０．３７ｇ／ｃｍ３であった。 <Manufacture of heat insulating material (heat insulating layer K)>
10 parts by mass of graphite ("AGB-5", manufactured by Ito Graphite Industries, average particle size 5 μm) was added to the formulation of the insulating material D and mixed to obtain a consistency of 70 to 140. Next, the obtained mixture was applied to a substrate to a thickness of 2.0 mm to form a coating film. Furthermore, the coating film was compression molded with a hot press machine to a sheet shape having a thickness of 1.0 mm and a density of 0.3 to 0.5 g/cm 3 , and then dried at 100°C for 10 minutes to produce an insulating material (insulating layer K) which is a molded body formed from a mixture containing hydrophilic fumed silica, glass fiber, graphite, and a non-polymeric dispersant. The obtained insulating material (insulating layer K) had a thickness of 1.0 mm and a density of 0.37 g/cm 3 .
　なお、断熱層Ｂ～Ｋの製造過程において、各混合液のちょう度は、日本産業規格ＪＩＳ Ｋ ２２２０：２０１３「グリース－第７部：ちょう度試験方法」に記載の内容に準拠して、「不混和ちょう度」として測定した。具体的には、円錐の分銅を降下させたときに分銅が接触しない程度の大きさのつぼを準備し、それに混合液を充填して、分銅が取り付けられた日化エンジニアリング製ＰＥＮＥＴＲＯ ＭＥＴＥＲに配置した。次に、分銅の位置を調節して、分銅と混合液が接触する位置に設定し、その位置を０点とした。そして、室温（２５℃）の条件下で、分銅を５秒間（±０．１秒）降下させて、混合液に侵入した分銅の深さ（ｍｍ）×１０をちょう度として算出した。なお、円錐の分銅は、日本産業規格に規定されている標準円錐であり、全質量が１０２．５ｇのものを、分銅の保持具の質量は、４７．５±０．０５ｇのものを使用した。 In the manufacturing process of the insulation layers B to K, the consistency of each mixed liquid was measured as "immiscible consistency" in accordance with the contents described in the Japanese Industrial Standard JIS K 2220:2013 "Grease - Part 7: Consistency test method". Specifically, a pot large enough that a conical weight would not come into contact with the mixture when lowered was prepared, filled with the mixed liquid, and placed in a Nikka Engineering PENETRO METER with a weight attached. The position of the weight was then adjusted so that it came into contact with the mixed liquid, and this position was designated as the zero point. The weight was then lowered for 5 seconds (±0.1 seconds) under room temperature (25°C) conditions, and the consistency was calculated as the depth (mm) of the weight that had penetrated into the mixed liquid x 10. The cone weight used was a standard cone as specified by the Japanese Industrial Standards, with a total mass of 102.5 g and a weight holder with a mass of 47.5 ± 0.05 g.
＜繊維成形体（緩衝層Ａ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（５００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成型した緩衝層Ａを作製した。得られた繊維成形体（緩衝層Ａ）の密度は０．１７ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer A)>
For the buffer layer, glass wool (uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer A. The density of the obtained fiber molding (buffer layer A) was 0.17 g/ cm3 .
＜繊維成形体（緩衝層Ｂ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（６００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｂを作製した。得られた繊維成形体（緩衝層Ｂ）の密度は０．１８ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer B)>
For the buffer layer, glass wool (uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer B. The density of the obtained fiber molding (buffer layer B) was 0.18 g/ cm3 .
＜繊維成形体（緩衝層Ｃ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（６００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｃを作製した。得られた繊維成形体（緩衝層Ｃ）の密度は０．２０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer C)>
For the buffer layer, glass wool (uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer C. The density of the obtained fiber molding (buffer layer C) was 0.20 g/ cm3 .
＜繊維成形体（緩衝層Ｄ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（７００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｄを作製した。得られた繊維成形体（緩衝層Ｄ）の密度は０．２１ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer D)>
For the buffer layer, glass wool (uncured wool (700 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer D. The density of the obtained fiber molding (buffer layer D) was 0.21 g/ cm3 .
＜繊維成形体（緩衝層Ｅ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（７００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール：含有量８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｅを作製した。得られた繊維成形体（緩衝層Ｅ）の密度は０．２３ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer E)>
For the buffer layer, glass wool (uncured wool (700 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer E. The density of the obtained fiber molding (buffer layer E) was 0.23 g/ cm3 .
＜繊維成形体（緩衝層Ｆ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（８００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｆを作製した。得られた繊維成形体（緩衝層Ｆ）の密度は０．２４ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer F)>
For the buffer layer, glass wool (uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer F. The density of the obtained fiber molding (buffer layer F) was 0.24 g/ cm3 .
＜繊維成形体（緩衝層Ｇ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（８００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｇを作製した。得られた繊維成形体（緩衝層Ｇ）の密度は０．２７ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer G)>
For the buffer layer, glass wool (uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer G. The density of the obtained fiber molding (buffer layer G) was 0.27 g/ cm3 .
＜繊維成形体（緩衝層Ｈ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１０００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｈを作製した。得られた繊維成形体（緩衝層Ｈ）の密度は０．３０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer H)>
For the buffer layer, glass wool (uncured wool (1000 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer H. The density of the obtained fiber molding (buffer layer H) was 0.30 g/ cm3 .
＜繊維成形体（緩衝層Ｉ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１０００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｉを作製した。得られた繊維成形体（緩衝層Ｉ）の密度は０．３３ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer I)>
For the buffer layer, glass wool (uncured wool (1000 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer I. The density of the obtained fiber molding (buffer layer I) was 0.33 g/ cm3 .
＜繊維成形体（緩衝層Ｊ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１２００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｊを作製した。得られた繊維成形体（緩衝層Ｊ）の密度は０．３６ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer J)>
For the buffer layer, glass wool (uncured wool (1200 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer J. The density of the obtained fiber molded product (buffer layer J) was 0.36 g/ cm3 .
＜繊維成形体（緩衝層Ｋ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１２００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｋを作製した。得られた繊維成形体（緩衝層Ｋ）の密度は０．４０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer K)>
As the buffer layer, glass wool (uncured wool (1200 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer K. The density of the obtained fiber molding (buffer layer K) was 0.40 g/ cm3 .
＜繊維成形体（緩衝層Ｌ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１４００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｌを作製した。得られた繊維成形体（緩衝層Ｌ）の密度は０．４２ｇ／ｃｍ３であった。 <Production of fiber molding (buffer layer L)>
For the buffer layer, glass wool (uncured wool (1400 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce a buffer layer L. The density of the obtained fiber molding (buffer layer L) was 0.42 g/ cm3 .
＜繊維成形体（緩衝層Ｍ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１５５６ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．６ｍｍの厚みに圧縮成形した緩衝層Ｍを作製した。得られた繊維成形体（緩衝層Ｍ）の密度は０．４４ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer M)>
For the buffer layer, glass wool (uncured wool (1556 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.6 mm to produce a buffer layer M. The density of the obtained fiber molding (buffer layer M) was 0.44 g/ cm3 .
＜繊維成形体（緩衝層Ｎ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１４００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｎを作製した。得られた繊維成形体（緩衝層Ｎ）の密度は０．４７ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer N)>
For the buffer layer, glass wool (uncured wool (1400 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce buffer layer N. The density of the obtained fiber molding (buffer layer N) was 0.47 g/ cm3 .
＜繊維成形体（緩衝層Ｏ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１６５６ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．３ｍｍの厚みに圧縮成形した緩衝層Ｏを作製した。得られた繊維成形体（緩衝層Ｏ）の密度は０．５０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer O)>
For the buffer layer, glass wool (uncured wool (1656 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.3 mm to produce buffer layer O. The density of the obtained fiber molding (buffer layer O) was 0.50 g/ cm3 .
＜繊維成形体（緩衝層Ｐ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１５５６ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径+：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２００℃の熱プレス機を使用し、２分間加熱し、グラスウール中の樹脂を熱硬化させ、３．０ｍｍの厚みに圧縮成形した緩衝層Ｐを作製した。得られた繊維成形体（緩衝層Ｐ）の密度は０．５２ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer P)>
For the buffer layer, glass wool (uncured wool (1556 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter+: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 2 minutes in a hot press at 200°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.0 mm to produce a buffer layer P. The density of the obtained fiber molding (buffer layer P) was 0.52 g/ cm3 .
＜繊維成形体（緩衝層Ｑ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（８００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、４．０ｍｍの厚みに圧縮成形した緩衝層Ｑを作製した。得られた繊維成形体（緩衝層Ｑ）の密度は０．２０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer Q)>
As the buffer layer, glass wool (uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 4.0 mm to produce a buffer layer Q. The density of the obtained fiber molding (buffer layer Q) was 0.20 g/ cm3 .
＜繊維成形体（緩衝層Ｒ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（８００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、４．２ｍｍの厚みに圧縮成形した緩衝層Ｒを作製した。得られた繊維成形体（緩衝層Ｒ）の密度は０．１９ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer R)>
For the buffer layer, glass wool (uncured wool (800 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 4.2 mm to produce a buffer layer R. The density of the obtained fiber molding (buffer layer R) was 0.19 g/ cm3 .
＜繊維成形体（緩衝層Ｓ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（１０５０ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、４．０ｍｍの厚みに圧縮成形した緩衝層Ｓを作製した。得られた繊維成形体（緩衝層Ｓ）の密度は０．２６ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer S)>
For the buffer layer, glass wool (uncured wool (1050 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 4.0 mm to produce a buffer layer S. The density of the obtained fiber molding (buffer layer S) was 0.26 g/ cm3 .
＜繊維成形体（緩衝層Ｔ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（９００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、３．５ｍｍの厚みに圧縮成形した緩衝層Ｔを作製した。得られた繊維成形体（緩衝層Ｔ）の密度は０．２５ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer T)>
For the buffer layer, glass wool (uncured wool (900 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.5 mm to produce a buffer layer T. The density of the obtained fiber molding (buffer layer T) was 0.25 g/ cm3 .
＜繊維成形体（緩衝層Ｕ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（５００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、３．５ｍｍの厚みに圧縮成形した緩衝層Ｕを作製した。なお、得られた繊維成形体（緩衝層Ｕ）の密度は０．１４ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer U)>
For the buffer layer, glass wool (uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 3.5 mm to produce a buffer layer U. The density of the obtained fiber molding (buffer layer U) was 0.14 g/ cm3 .
＜繊維成形体（緩衝層Ｖ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（５００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、５．０ｍｍの厚みに圧縮成形した緩衝層Ｖを作製した。得られた繊維成形体（緩衝層Ｖ）の密度は０．１０ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer V)>
For the buffer layer, glass wool (uncured wool (500 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 5.0 mm to produce buffer layer V. The density of the obtained fiber molding (buffer layer V) was 0.10 g/ cm3 .
＜繊維成形体（緩衝層Ｗ）の製造＞
　緩衝層として、グラスウール（アンキュアードウール（６００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ、グラスウール含有量：８０～９０質量％、フェノールバインダー含有量：１０～２０質量％）を２４０℃の熱プレス機を使用して、１分間加熱し、グラスウール中の樹脂を熱硬化させ、５．０ｍｍの厚みに圧縮成形した緩衝層Ｗを作製した。得られた繊維成形体（緩衝層Ｗ）の密度は０．１２ｇ／ｃｍ３であった。 <Production of fiber molded body (buffer layer W)>
For the buffer layer, glass wool (uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm, glass wool content: 80-90% by mass, phenol binder content: 10-20% by mass) was heated for 1 minute using a hot press machine at 240°C to thermally cure the resin in the glass wool, and compression molded to a thickness of 5.0 mm to produce a buffer layer W. The density of the obtained fiber molding (buffer layer W) was 0.12 g/ cm3 .
＜繊維成形体（緩衝層Ｘ）＞
　グラスウール（アンキュアードウール（６００ｇ／ｍ２）、セントラルグラスファイバー社製　プレス用原綿、平均繊維径：７μｍ％）に、熱可塑性のバインダー（ＤＩＣ社製のブタジエン・メチルメタアクリレート（ＭＢＲ）ラテックス、製品名「ラックスターＤＭ―８２０」を含浸させ、１８０℃の熱プレス機を使用して、７分間加熱し、ラテックス中の水分を蒸発させ、２．９ｍｍの厚みに圧縮成形した緩衝層Ｘを作製した。なお、得られた繊維成形体（緩衝層Ｘ）の密度は０．１８ｇ／ｃｍ３であり、ＭＢＲ含有率は３２質量％であった。 <Fiber molded body (buffer layer X)>
Glass wool (uncured wool (600 g/ m2 ), raw cotton for pressing manufactured by Central Glass Fiber, average fiber diameter: 7 μm%) was impregnated with a thermoplastic binder (butadiene-methyl methacrylate (MBR) latex manufactured by DIC Corporation, product name "Lackstar DM-820" and heated for 7 minutes using a hot press machine at 180°C to evaporate the water in the latex, and a buffer layer X was compression molded to a thickness of 2.9 mm. The density of the obtained fiber molding (buffer layer X) was 0.18 g/ cm3 and the MBR content was 32 mass%.
＜有機フォーム（緩衝層Ｙ）＞
　緩衝層Ｙとして、宮原ゴム工業社製のＮＲフォーム（２９７５ｇ／ｍ２、厚み８．５ｍｍ、　トムソン＃５２）を使用した。密度は０．３５ｇ／ｃｍ３であった。 <Organic foam (buffer layer Y)>
NR foam (2975 g/m 2 , thickness 8.5 mm, Thomson #52) manufactured by Miyahara Rubber Industries Co., Ltd. was used as the buffer layer Y. The density was 0.35 g/cm 3 .
＜有機フォーム（緩衝層Ｚ）＞
　緩衝層Ｚとして、昇英新材料科技（常州）有限責任公司製のウレタンフォーム（２８８０ｇ／ｍ２、厚み６ｍｍ、製品名「ＭｉｃｒｏＦｏａｍ（商標）ＰＨ－４８０－６Ｔ－ＲＰ」）を使用した。密度は０．４８ｇ／ｃｍ３であった。 <Organic foam (buffer layer Z)>
Urethane foam (2880 g/m 2 , thickness 6 mm, product name "MicroFoam (trademark) PH-480-6T-RP") manufactured by Shengying New Material Technology (Changzhou) Co., Ltd. was used as the buffer layer Z. The density was 0.48 g/cm 3 .
＜断熱層と緩衝層の密度測定＞
　断熱層Ａ～Ｋおよび緩衝層Ａ～Ｚの密度測定は、下記の方法により行った。
　各断熱層または緩衝層を２０ｍｍ×２０ｍｍの大きさに切断し、質量、厚みを測定して、質量を体積で除算して密度［ｇ／ｃｍ３］を算出した。結果を表３－１、表３－２、表４－１および表４－２に示す。 <Density measurement of insulation layer and buffer layer>
The density of the heat insulating layers A to K and the buffer layers A to Z was measured by the following method.
Each heat insulating layer or buffer layer was cut to a size of 20 mm x 20 mm, the mass and thickness were measured, and the mass was divided by the volume to calculate the density [g/cm 3 ]. The results are shown in Tables 3-1, 3-2, 4-1 and 4-2.
＜断熱層、緩衝層の圧縮試験＞
　断熱層Ａ～Ｋおよび緩衝層Ａ～Ｚについて、下記の方法により圧縮試験を行った。
　精密万能試験機（オートグラフＡＧＳ－５ｋＮＸ、株式会社島津製作所製）を使用して、圧縮速度０．５ｍｍ／ｍｉｎで断熱層と緩衝層をそれぞれ圧縮する圧縮試験を行い、圧縮ひずみ［％］（圧縮変位量／試験体の初期厚み）と圧縮応力［ＭＰａ］を測定した。得られた各応力－ひずみ曲線（Ｓ－Ｓカーブ）を図９～３１に示す。また、断熱層Ａ～Ｅについて、式（ａ１－１）と式（ａ１－２）を満たす圧縮状態、式（ａ２－１）と式（ａ２－２）を満たす圧縮状態、式（ａ３－１）と式（ａ３－２）を満たす圧縮状態があるかどうか、緩衝層Ａ～Ｐについて、式（ｂ１－１）と式（ｂ１－２）を満たす圧縮状態、式（ｂ２－１）と式（ｂ２－２）を満たす圧縮状態、式（ｂ３－１）と式（ｂ３－２）を満たす圧縮状態、式（ｂ４－１）と式（ｂ４－２）を満たす圧縮状態があるかどうかを検討した。結果を表１および表２－１～表２－４に示す。各断熱層と各緩衝層について、上記圧縮試験において圧縮応力が０．３４ＭＰａ、１．００ＭＰａ、１．３９ＭＰａ、３．４５ＭＰａとなったときの厚みと圧縮ひずみの値を表３－１および表３－２、表４－１および表４－２に示す。
　なお、表４－１中の上向き矢印は、該矢印が記入されたセルの内容が、その上のセルに記入された内容と同じであることを示している。 <Compression test of heat insulation layer and buffer layer>
The heat insulating layers A to K and the buffer layers A to Z were subjected to a compression test by the following method.
A compression test was performed by compressing the heat insulating layer and the buffer layer at a compression speed of 0.5 mm/min using a precision universal testing machine (Autograph AGS-5kNX, manufactured by Shimadzu Corporation), and the compressive strain [%] (compressive displacement amount/initial thickness of the test specimen) and compressive stress [MPa] were measured. The obtained stress-strain curves (S-S curves) are shown in Figures 9 to 31. In addition, for the thermal insulation layers A to E, whether there is a compressed state that satisfies the formula (a1-1) and the formula (a1-2), a compressed state that satisfies the formula (a2-1) and the formula (a2-2), or a compressed state that satisfies the formula (a3-1) and the formula (a3-2), and for the buffer layers A to P, whether there is a compressed state that satisfies the formula (b1-1) and the formula (b1-2), a compressed state that satisfies the formula (b2-1) and the formula (b2-2), a compressed state that satisfies the formula (b3-1) and the formula (b3-2), or a compressed state that satisfies the formula (b4-1) and the formula (b4-2) was examined. The results are shown in Table 1 and Tables 2-1 to 2-4. For each thermal insulation layer and each buffer layer, the thickness and compressive strain values when the compressive stress in the above compression test was 0.34 MPa, 1.00 MPa, 1.39 MPa, and 3.45 MPa are shown in Tables 3-1 and 3-2, Tables 4-1 and 4-2.
In addition, an upward arrow in Table 4-1 indicates that the content of the cell in which the arrow is written is the same as the content written in the cell above it.
　さらに、断熱層Ａ～Ｅについて、ひずみをｘ軸、応力をｙ軸とするグラフにおける応力－ひずみ曲線の形状と領域（ａ１）（すなわち、式（ａ１－１）と式（ａ１－２）で囲まれた領域。以下同様。）、領域（ａ２）、領域（ａ３）との関係を、以下の基準により点数化した。結果を表３－１に示す。
　０点：領域（ａ１）～（ａ３）のいずれも通過しない。
　１点：領域（ａ１）を通過する。
　（領域（ａ１）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　２点：領域（ａ２）を通過する。
　（領域（ａ２）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　３点：領域（ａ３）を通過する。
　（領域（ａ３）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　なお、各領域の上端線、下端線とは、その領域を区画する線のうちｘ軸に平行な２つの直線をいう（以下において同じ。）。 Furthermore, for the thermal insulation layers A to E, the shape of the stress-strain curve in a graph with strain on the x-axis and stress on the y-axis and the relationship with region (a1) (i.e., the region surrounded by formula (a1-1) and formula (a1-2); the same applies below), region (a2), and region (a3) were scored according to the following criteria. The results are shown in Table 3-1.
0 point: None of the areas (a1) to (a3) are passed.
1 point: Pass through area (a1).
(If the line crosses both the top and bottom lines of the area (a1), 0.5 points will be added.)
2 points: Pass through area (a2).
(If the line crosses both the top and bottom lines of the area (a2), 0.5 points will be added.)
3 points: Pass through area (a3).
(If the line crosses both the top and bottom lines of the area (a3), 0.5 points will be added.)
The upper and lower end lines of each region refer to two straight lines parallel to the x-axis among the lines dividing the region (the same applies hereinafter).
　また、断熱層Ｆ～Ｋについて、ひずみをｘ軸、応力をｙ軸とするグラフにおける応力－ひずみ曲線の形状と領域（ａ４）～（ａ６）との関係を、以下の基準により点数化した。結果を表３－２に示す。
　０点：領域（ａ４）～（ａ６）のいずれも通過しない。
　１点：領域（ａ４）を通過する。
　（領域（ａ４）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　２点：領域（ａ５）を通過する。
　（領域（ａ５）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　３点：領域（ａ６）を通過する。
　（領域（ａ６）の上端線と下端線の両方を横切る場合には、０．５点を加点する。） In addition, for the thermal insulation layers F to K, the relationship between the shape of the stress-strain curve and the regions (a4) to (a6) in a graph with strain on the x-axis and stress on the y-axis was scored according to the following criteria. The results are shown in Table 3-2.
0 points: None of the areas (a4) to (a6) are passed through.
1 point: Pass through area (a4).
(If the line crosses both the top and bottom lines of the area (a4), 0.5 points will be added.)
2 points: Pass through area (a5).
(If the line crosses both the top and bottom lines of the area (a5), add 0.5 points.)
3 points: Pass through area (a6).
(If the line crosses both the top and bottom lines of the area (a6), 0.5 points will be added.)
　同様に、緩衝層Ａ～Ｔについて、ひずみをｘ軸、応力をｙ軸とするグラフにおける応力－ひずみ曲線の形状と領域（ｂ１）～（ｂ４）との関係を、以下の基準により点数化した。結果を表４－１に示す。
　０点：領域（ｂ１）～（ｂ４）のいずれも通過しない。
　１点：領域（ｂ１）を通過する。
　（領域（ｂ１）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　２点：領域（ｂ２）を通過する。
　（領域（ｂ２）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　３点：領域（ｂ３）を通過する。
　（領域（ｂ３）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　４点：領域（ｂ４）を通過する。
　（領域（ｂ４）の上端線と下端線の両方を横切る場合には、０．５点を加点する。） Similarly, for the buffer layers A to T, the relationship between the shape of the stress-strain curve in a graph with strain on the x-axis and stress on the y-axis and the regions (b1) to (b4) was scored according to the following criteria. The results are shown in Table 4-1.
0 point: None of the areas (b1) to (b4) are passed through.
1 point: Pass through area (b1).
(If the line crosses both the top and bottom lines of the area (b1), 0.5 points will be added.)
2 points: Pass through area (b2).
(If the line crosses both the top and bottom lines of the area (b2), 0.5 points will be added.)
3 points: Pass through area (b3).
(If the line crosses both the top and bottom lines of the area (b3), 0.5 points will be added.)
4 points: Pass through area (b4).
(If the line crosses both the top and bottom lines of the area (b4), 0.5 points will be added.)
　また、緩衝層Ｕ～Ｚについて、ひずみをｘ軸、応力をｙ軸とするグラフにおける応力－ひずみ曲線の形状と領域（ｂ５）～（ｂ８）との関係を、以下の基準により点数化した。結果を表４－２に示す。
　０点：領域（ｂ５）～（ｂ８）のいずれも通過しない。
　１点：領域（ｂ５）を通過する。
　（領域（ｂ５）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　２点：領域（ｂ６）を通過する。
　（領域（ｂ６）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　３点：領域（ｂ７）を通過する。
　（領域（ｂ７）の上端線と下端線の両方を横切る場合には、０．５点を加点する。）
　４点：領域（ｂ８）を通過する。
　（領域（ｂ８）の上端線と下端線の両方を横切る場合には、０．５点を加点する。） In addition, for the buffer layers U to Z, the relationship between the shape of the stress-strain curve in a graph with strain on the x-axis and stress on the y-axis and the regions (b5) to (b8) was scored according to the following criteria. The results are shown in Table 4-2.
0 points: None of the areas (b5) to (b8) are passed through.
1 point: Pass through area (b5).
(If the ball crosses both the top and bottom lines of the area (b5), 0.5 points will be added.)
2 points: Pass through area (b6).
(If the ball crosses both the top and bottom lines of the area (b6), 0.5 points will be added.)
3 points: Pass through area (b7).
(If the ball crosses both the top and bottom lines of the area (b7), 0.5 points will be added.)
4 points: Pass through area (b8).
(If the ball crosses both the top and bottom lines of the area (b8), 0.5 points will be added.)
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
＜断熱層の熱伝導率測定＞
　断熱層Ａ～Ｋについて、下記の方法により熱伝導率を測定した。
　熱伝導率は、日本産業規格ＪＩＳ Ａ　１４１２－２：１９９９「熱絶縁材の熱抵抗および熱伝導率の測定方法－第２部：熱流計法（ＨＦＭ法）」に記載の内容に準拠して、８０℃、２ＭＰａ条件下と６００℃、２ＭＰａ条件下の２通りの測定をそれぞれ行った。まず、断熱層（加圧していないときの厚みが２ｍｍ）を２０ｍｍ×２０ｍｍの大きさに切断してサンプルを作製した。サンプル、参照試料（アルミナコンポジットマテリアル（「ＲＳ－１００」、ＺＩＲＣＡＲ　Ｒｅｆｒａｃｔｏｒｙ　Ｃｏｍｐｏｓｉｔｅｓ，　Ｉｎｃ．製、厚さ：５ｍｍ、熱伝導率：０．６６Ｗ／（ｍ・Ｋ）））、チタン板（厚さ０．２ｍｍ）を準備した。次に、空圧プレス機（井元製作所社製）の下盤面に、上から、熱電対１（シース熱電対Ｋタイプ（ＳＣＨＳ１－０）、φ＝０．１５、クラスＪＩＳ１、チノー社製）、チタン板、試験体として断熱層、チタン板、熱電対２（シース熱電対Ｋタイプ（ＳＣＨＳ１－０）、φ＝０．１５、クラスＪＩＳ１、チノー社製）、標準板、熱電対３（シース熱電対Ｋタイプ（ＳＣＨＳ１－０）、φ＝０．１５、クラスＪＩＳ１、チノー社製）の順に挟んで断熱層、標準板、熱電対等を密着させた。次に上盤と下盤を加温してプレス機の荷重が８００Ｎ（２ＭＰａ相当）になるように調整した後、加圧した。加温加圧された状態で、熱電対の検出温度が安定するまで測定を継続した。なお、測定温度としては、上盤を８０℃、下盤を３０℃にした場合と、上盤を６００℃、下盤を４０℃にした場合の２通りの測定をそれぞれ行った。また、温度が安定したとは、１０分継時前後での温度変化が±０．１℃以内になることとした。温度安定後の各熱電対の検出温度と断熱層の圧縮時の厚み、標準試料の熱伝導率と厚みから、断熱層の熱伝導率ｋ１を以下の式（Ｉ）により求めた。得られた断熱層の熱伝導率を、表３－３に示す。
　ｋ１＝ｋ２×（Ｌ１×ΔＴ１）／（Ｌ２×ΔＴ２）　・・・（Ｉ）
（式中、ｋ１は断熱層の熱伝導率［Ｗ／（ｍ・Ｋ）］、ｋ２は標準板の熱伝導率［Ｗ／（ｍ・Ｋ）］、Ｌ１は断熱層の加圧時厚み、Ｌ２は標準板の厚み、ΔＴ１は第２熱電対（熱電対２）の温度と第３熱電対（熱電対３）の温度との温度差、ΔＴ２は第１熱電対（熱電対１）の温度と第２熱電対（熱電対２）の温度との温度差である。） <Measurement of thermal conductivity of heat insulating layer>
The thermal conductivity of the heat insulating layers A to K was measured by the following method.
The thermal conductivity was measured in two ways, under conditions of 80°C and 2 MPa and 600°C and 2 MPa, in accordance with the contents described in the Japanese Industrial Standards JIS A 1412-2:1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulation materials - Part 2: Heat flow meter method (HFM method)". First, a sample was prepared by cutting the insulation layer (thickness 2 mm when not pressurized) into a size of 20 mm x 20 mm. A sample, a reference sample (alumina composite material ("RS-100", manufactured by ZIRCAR Refractory Composites, Inc., thickness: 5 mm, thermal conductivity: 0.66 W/(m·K))), and a titanium plate (thickness 0.2 mm) were prepared. Next, on the lower plate surface of a pneumatic press (manufactured by Imoto Seisakusho Co., Ltd.), from the top, thermocouple 1 (sheathed thermocouple type K (SCHS1-0), φ = 0.15, class JIS 1, manufactured by Chino Co., Ltd.), titanium plate, a heat insulating layer as a test specimen, titanium plate, thermocouple 2 (sheathed thermocouple type K (SCHS1-0), φ = 0.15, class JIS 1, manufactured by Chino Co., Ltd.), standard plate, thermocouple 3 (sheathed thermocouple type K (SCHS1-0), φ = 0.15, class JIS 1, manufactured by Chino Co., Ltd.) were sandwiched in this order to bring the heat insulating layer, standard plate, thermocouple, etc. into close contact. Next, the upper plate and the lower plate were heated and adjusted so that the load of the press machine was 800 N (equivalent to 2 MPa), and then pressurized. In the heated and pressurized state, the measurement was continued until the detected temperature of the thermocouple stabilized. The measurement temperatures were two: upper plate 80°C, lower plate 30°C, and upper plate 600°C, lower plate 40°C. The temperature was considered to be stable when the temperature change was within ±0.1°C after 10 minutes. The thermal conductivity k1 of the thermal insulation layer was calculated from the temperature detected by each thermocouple after the temperature was stabilized, the thickness of the thermal insulation layer when compressed, and the thermal conductivity and thickness of the standard sample, using the following formula (I). The thermal conductivity of the thermal insulation layer obtained is shown in Table 3-3.
k1=k2×(L1×ΔT1)/(L2×ΔT2) (I)
(In the formula, k1 is the thermal conductivity of the insulating layer [W/(m K)], k2 is the thermal conductivity of the standard plate [W/(m K)], L1 is the thickness of the insulating layer when pressed, L2 is the thickness of the standard plate, ΔT1 is the temperature difference between the temperature of the second thermocouple (thermocouple 2) and the temperature of the third thermocouple (thermocouple 3), and ΔT2 is the temperature difference between the temperature of the first thermocouple (thermocouple 1) and the temperature of the second thermocouple (thermocouple 2).)
（熱抵抗）
　断熱層の熱抵抗は、前述の熱伝導率ｋ１と加圧時厚みＬ１から、下記式（ＩＩ）により算出した。得られた断熱層の熱抵抗を、表３－３に示す。
　Ｒ１＝Ｌ１／ｋ１　・・・（ＩＩ）
（式中、Ｒ１は断熱層の熱抵抗［（ｍ２・Ｋ）／Ｗ］、ｋ１は断熱層の熱伝導率［Ｗ／（ｍ・Ｋ）］、Ｌ１は断熱層の加圧時厚みである。） (Thermal resistance)
The thermal resistance of the insulating layer was calculated from the above-mentioned thermal conductivity k1 and thickness under pressure L1 according to the following formula (II). The obtained thermal resistance of the insulating layer is shown in Table 3-3.
R1=L1/k1 (II)
(In the formula, R1 is the thermal resistance of the insulating layer [( m2 ·K)/W], k1 is the thermal conductivity of the insulating layer [W/(m·K)], and L1 is the thickness of the insulating layer when pressed.)
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　表４－１においてＳ－Ｓカーブ形状の点数により示されているように、緩衝層Ａ～Ｔは、いずれも、圧縮試験において少なくとも領域（ｂ１）を通る応力－ひずみ曲線を与えるものであった（図１６～２８参照）。 As shown by the scores for the S-S curve shape in Table 4-1, all of the buffer layers A to T provided stress-strain curves that passed through at least region (b1) in the compression test (see Figures 16 to 28).
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　表４－２においてＳ－Ｓカーブ形状の点数により示されているように、緩衝層Ｕ～Ｚは、いずれも、圧縮試験において少なくとも領域（ｂ５）を通る応力－ひずみ曲線を与えるものであった（図２９～３１参照）。 As shown by the scores of the S-S curve shape in Table 4-2, all of the buffer layers U to Z gave stress-strain curves that passed through at least region (b5) in the compression test (see Figures 29 to 31).
＜断熱材（断熱層＋緩衝層）の製造＞
（実施例１）
　断熱層Ｂと緩衝層Ａを組み合わせて積層し、その積層物を通気口付きの被覆層で覆って断熱材を製造した。具体的には、断熱層Ｂと緩衝層Ａとの積層物の上面および下面にポリエチレンテレフタレート（ＰＥＴ）系のシュリンクフィルム（三菱ケミカル社製、製品名「ヒシペットＰＸ－４０Ｓ」、厚さ２０μｍ）を１枚ずつ積層し、上記シュリンクフィルムを上記積層物の平面形状よりも面積比で１０％大きいサイズに溶断して上下のフィルムを上記積層物の周囲で溶着させ、次いで上記フィルムに針またはレーザーにより通気口用の貫通孔を形成した後、加熱炉にて９５℃で１５秒間加熱してフィルムをシュリンクさせることにより、実施例１に係る断熱材を得た。なお、上記通気口は、後述する載荷－除荷試験において被覆層の内部（上記積層物の収容空間）と外部との間での空気の流通を十分に許容できるように形成した。 <Manufacture of insulation material (insulation layer + buffer layer)>
Example 1
The heat insulating layer B and the buffer layer A were laminated together, and the laminate was covered with a coating layer with a vent hole to produce a heat insulating material. Specifically, a polyethylene terephthalate (PET) shrink film (manufactured by Mitsubishi Chemical Corporation, product name "Hishipet PX-40S", thickness 20 μm) was laminated one by one on the upper and lower surfaces of the laminate of the heat insulating layer B and the buffer layer A, and the shrink film was cut into a size 10% larger in area than the planar shape of the laminate, and the upper and lower films were welded around the laminate, and then a through hole for the ventilation hole was formed in the film with a needle or a laser, and the film was shrunk by heating it in a heating furnace at 95 ° C. for 15 seconds to obtain a heat insulating material according to Example 1. The ventilation hole was formed so as to fully allow the flow of air between the inside of the coating layer (the storage space of the laminate) and the outside in the loading-unloading test described later.
（実施例２～１６）
　断熱層と緩衝層との組合せを表５－１に示すとおりとした他は実施例１と同様の作製手順にて断熱材を作製した。 (Examples 2 to 16)
The heat insulating materials were prepared in the same manner as in Example 1, except that the combinations of the heat insulating layer and the buffer layer were as shown in Table 5-1.
（実施例１７～２５）
　断熱層と緩衝層との組合せを表５－２に示すとおりとした他は実施例１と同様の作製手順にて断熱材を作製した。 (Examples 17 to 25)
The heat insulating materials were prepared in the same manner as in Example 1, except that the combinations of the heat insulating layer and the buffer layer were as shown in Table 5-2.
＜載荷－除荷試験１；高圧力条件）＞
　実施例１～２５について、下記の方法により、載荷－除荷試験を行い、下記の各地点における断熱材の厚みと圧縮ひずみを測定した。
　精密万能試験機（オートグラフＡＧＳ－５ｋＮＸ、株式会社島津製作所製）を使用し、圧縮速度０．５ｍｍ／ｍｉｎで圧縮応力が３．４５ＭＰａとなるまで断熱材を圧縮した後、圧縮速度０．５ｍｍ／ｍｉｎで圧縮応力がゼロになるまで断熱材への圧縮を解放した。上記の載荷－除荷試験を模式的に表した応力－ひずみ曲線（Ｓ－Ｓカーブ）を図３２に示す。
　上記載荷－除荷試験の圧縮過程における圧力０．３４ＭＰａ時と圧力３．４５ＭＰａ時の断熱材の圧縮変位を抽出するとともに、さらに圧縮解放過程において、圧縮過程の圧縮応力０．３４ＭＰａと同一変位になる圧縮状態の断熱材の圧縮変位を抽出し、各地点における断熱材の厚みと圧縮変位を算出した。結果を表５－１および表５－４に示す。表５－１、表５－４には、圧縮過程における圧力０．３４ＭＰａ時の圧縮ひずみを圧力３．４５ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｈｐ））と、圧縮解放過程における上記圧縮状態（すなわち、圧縮過程の圧縮応力０．３４ＭＰａと同一変位になる圧縮状態）での圧縮ひずみを圧力３．４５ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｈｒ））を併せて示している。 <Loading-unloading test 1; high pressure conditions>
For Examples 1 to 25, a load-unload test was carried out by the following method, and the thickness and compressive strain of the insulating material were measured at each of the following points.
Using a precision universal testing machine (Autograph AGS-5kNX, manufactured by Shimadzu Corporation), the heat insulating material was compressed at a compression speed of 0.5 mm/min until the compressive stress reached 3.45 MPa, and then the heat insulating material was released at a compression speed of 0.5 mm/min until the compressive stress reached zero. A stress-strain curve (S-S curve) that shows a schematic representation of the above loading-unloading test is shown in FIG.
The compression displacement of the insulation material at pressures of 0.34 MPa and 3.45 MPa during the compression process of the above-mentioned load-unload test was extracted, and the compression displacement of the insulation material in the compressed state that has the same displacement as the compressive stress of 0.34 MPa during the compression process during the compression release process was extracted, and the thickness and compression displacement of the insulation material at each point were calculated. The results are shown in Tables 5-1 and 5-4. Tables 5-1 and 5-4 also show the value (strain difference (Xhp)) obtained by subtracting the compressive strain at a pressure of 0.34 MPa during the compression process from the compressive strain at a pressure of 3.45 MPa, and the value (strain difference (Xhr)) obtained by subtracting the compressive strain in the above-mentioned compressed state during the compression release process (i.e., the compressed state that has the same displacement as the compressive stress of 0.34 MPa during the compression process) from the compressive strain at a pressure of 3.45 MPa.
＜載荷－除荷試験２；低圧力条件＞
　実施例１～２５について、下記の方法により、載荷－除荷試験を行い、下記の各地点における断熱材の厚みと圧縮ひずみを測定した。
　精密万能試験機（オートグラフＡＧＳ－５ｋＮＸ、株式会社島津製作所製）を使用し、圧縮速度０．５ｍｍ／ｍｉｎで圧縮応力が１．３９ＭＰａとなるまで断熱材を圧縮した後、圧縮速度０．５ｍｍ／ｍｉｎで圧縮応力がゼロになるまで断熱材への圧縮を解放した。上記の載荷－除荷試験を模式的に表した応力－ひずみ曲線（Ｓ－Ｓカーブ）を図３３に示す。
　上記載荷－除荷試験の圧縮過程における圧力０．０３ＭＰａ時と圧力１．３９ＭＰａ時の断熱材の圧縮変位を抽出するとともに、さらに圧縮解放過程において、圧縮過程の圧縮応力０．０３ＭＰａと同一変位になる圧縮状態の断熱材の圧縮変位を抽出し、各地点における断熱材の厚みと圧縮変位を算出した。結果を表５－２および表５－３に示す。表５－２、表５－３には、圧縮過程における圧力０．０３ＭＰａ時の圧縮ひずみを圧力１．３９ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｌｐ））と、圧縮解放過程における上記圧縮状態（すなわち、圧縮過程の圧縮応力０．０３ＭＰａと同一変位になる圧縮状態）での圧縮ひずみを圧力１．３９ＭＰａ時の圧縮ひずみから減算した値（ひずみ差分（Ｘｌｒ））を併せて示している。 <Loading-unloading test 2: Low pressure conditions>
For Examples 1 to 25, a load-unload test was carried out by the following method, and the thickness and compressive strain of the insulating material were measured at each of the following points.
Using a precision universal testing machine (Autograph AGS-5kNX, manufactured by Shimadzu Corporation), the heat insulating material was compressed at a compression speed of 0.5 mm/min until the compressive stress reached 1.39 MPa, and then the heat insulating material was released at a compression speed of 0.5 mm/min until the compressive stress reached zero. A stress-strain curve (S-S curve) that shows a schematic representation of the above loading-unloading test is shown in FIG.
The compression displacement of the insulation material at a pressure of 0.03 MPa and a pressure of 1.39 MPa during the compression process of the above-mentioned load-unload test was extracted, and the compression displacement of the insulation material in a compressed state that has the same displacement as the compressive stress of 0.03 MPa during the compression process during the compression release process was extracted, and the thickness and compression displacement of the insulation material at each point were calculated. The results are shown in Tables 5-2 and 5-3. Tables 5-2 and 5-3 also show the value (strain difference (Xlp)) obtained by subtracting the compressive strain at a pressure of 0.03 MPa during the compression process from the compressive strain at a pressure of 1.39 MPa, and the value (strain difference (Xlr)) obtained by subtracting the compressive strain in the above-mentioned compressed state during the compression release process (i.e., the compressed state that has the same displacement as the compressive stress of 0.03 MPa during the compression process) from the compressive strain at a pressure of 1.39 MPa.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　表５－１に示されるように、単独での圧縮試験において少なくとも領域（ｂ１）を通過する応力－ひずみ曲線を与える緩衝層を備えた実施例１～１６の断熱材は、高圧力条件での載荷－除荷試験１において、いずれも圧縮過程のひずみ差分（Ｘｈｐ）が１５％以上、圧縮解放過程のひずみ差分（Ｘｈｒ）が５％であり、圧力に対して厚みが適切に変動するものであった。これらの断熱材は、Ｓ－Ｓカーブ形状の合計点がいずれも４．０以上であった。このことから、ひずみをｘ軸、応力をｙ軸とするグラフ上に設定した領域との関係で、断熱層のＳ－Ｓカーブ形状と緩衝層のＳ－Ｓカーブ形状との合計点が所定以上となるように断熱層および緩衝層を適切に組み合わせることにより、バッテリーモジュール等においてセル間に配置される断熱材として用いられ得る圧縮特性を示す断熱材を効率よく実現できることがわかる。また、Ｓ－Ｓカーブ形状の合計点がいずれも６．０以上である断熱材は、いずれも、圧縮過程のひずみ差分（Ｘｈｐ）が３０％以上、圧縮解放過程のひずみ差分（Ｘｈｒ）が６％以上という、より良好な圧縮特性を示した。 As shown in Table 5-1, the insulating materials of Examples 1 to 16, which have a buffer layer that gives a stress-strain curve that passes through at least region (b1) in a compression test alone, all had a strain difference (Xhp) during the compression process of 15% or more and a strain difference (Xhr) during the compression release process of 5% in a loading-unloading test 1 under high pressure conditions, and the thickness changed appropriately with respect to pressure. The total point of the S-S curve shape of all of these insulating materials was 4.0 or more. From this, it can be seen that by appropriately combining the insulating layer and the buffer layer so that the total point of the S-S curve shape of the insulating layer and the S-S curve shape of the buffer layer is a predetermined value or more in relation to the region set on a graph with strain on the x-axis and stress on the y-axis, it is possible to efficiently realize an insulating material that exhibits compression characteristics that can be used as an insulating material to be placed between cells in a battery module, etc. Additionally, all insulation materials with a total S-S curve shape score of 6.0 or more showed better compression characteristics, with a strain difference during the compression process (Xhp) of 30% or more and a strain difference during the compression/release process (Xhr) of 6% or more.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　表５－２に示されるように、単独での圧縮試験において少なくとも領域（ｂ５）を通過する応力－ひずみ曲線を与える緩衝層を備えた実施例１７～２６の断熱材は、低圧力条件での載荷－除荷試験２において、いずれも圧縮過程のひずみ差分（Ｘｌｐ）が１５％以上、圧縮解放過程のひずみ差分（Ｘｌｒ）が５％であり、圧力に対して厚みが適切に変動するものであった。これらの断熱材は、領域（ａ６）を通過する応力－ひずみ曲線を与える断熱層と、領域（ｂ８）を通過する応力－ひずみ曲線を与える緩衝層との組合せであり、Ｓ－Ｓカーブ形状の合計点はいずれも６．０以上であって、圧縮過程のひずみ差分（Ｘｌｐ）が３０％以上、圧縮解放過程のひずみ差分（Ｘｌｒ）が６％以上という優れた圧縮特性を示した。これにより、ひずみをｘ軸、応力をｙ軸とするグラフ上に設定した領域との関係で、断熱層のＳ－Ｓカーブ形状と緩衝層のＳ－Ｓカーブ形状との合計点が所定以上となるように断熱層および緩衝層を適切に組み合わせることにより、バッテリーモジュール等においてセル間に配置される断熱材として用いられ得る圧縮特性を示す断熱材を効率よく実現できることが確かめられた。 As shown in Table 5-2, the insulation materials of Examples 17 to 26, which have a buffer layer that gives a stress-strain curve that passes through at least region (b5) in a compression test alone, all had a strain difference (Xlp) during the compression process of 15% or more and a strain difference (Xlr) during the compression-release process of 5% in the loading-unloading test 2 under low pressure conditions, and the thickness changed appropriately with respect to pressure. These insulation materials are combinations of an insulation layer that gives a stress-strain curve that passes through region (a6) and a buffer layer that gives a stress-strain curve that passes through region (b8), and all of the total points of the S-S curve shapes were 6.0 or more, and showed excellent compression characteristics, with a strain difference (Xlp) during the compression process of 30% or more and a strain difference (Xlr) during the compression-release process of 6% or more. This confirmed that by appropriately combining the insulating layer and the buffer layer so that the sum of the S-S curve shape of the insulating layer and the S-S curve shape of the buffer layer is equal to or greater than a predetermined value in relation to the region set on a graph with strain on the x-axis and stress on the y-axis, it is possible to efficiently realize an insulating material that exhibits compression characteristics that can be used as an insulating material placed between cells in a battery module, etc.
　なお、以下の表５－３には実施例１～１６に係る断熱材を載荷－除荷試験２（低圧力条件）により評価した結果を示し、以下の表５－４には実施例１７～２５に係る断熱材を載荷－除荷試験１（高圧力条件）により評価した結果を示している。 Table 5-3 below shows the results of evaluating the insulation materials of Examples 1 to 16 through load-unload test 2 (low pressure conditions), and Table 5-4 below shows the results of evaluating the insulation materials of Examples 17 to 25 through load-unload test 1 (high pressure conditions).
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000013
Figure JPOXMLDOC01-appb-T000014
Figure JPOXMLDOC01-appb-T000014
　以上、本発明の具体例を詳細に説明したが、これらは例示にすぎず、特許請求の範囲を限定するものではない。特許請求の範囲に記載の技術には、以上に例示した具体例を様々に変形、変更したものが含まれる。 　Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples given above.
　　１、５２　断熱材
　１０、１０Ａ、１０Ｂ、５２１　断熱層
　２０、２０Ａ、２０Ｂ、５２２　緩衝層
　３０、５２３　被覆材（被覆層）
　３１Ａ、３１Ｂ　樹脂フィルム
　３２　シール部
　３３　通気口
　３４　通気膜
　４０　接着層
　５０　バッテリーモジュール
　５１　電池セル

  1, 52 Insulation material 10, 10A, 10B, 521 Insulation layer 20, 20A, 20B, 522 Buffer layer 30, 523 Coating material (coating layer)
31A, 31B Resin film 32 Sealing portion 33 Vent 34 Ventilating film 40 Adhesive layer 50 Battery module 51 Battery cell

Claims (24)

  1. 　無機粒子を含んでなる断熱層と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層と、を有する断熱材であって、
    　前記緩衝層が、前記緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ１－１）および下記式（ｂ１－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、断熱材。
    　式（ｂ１－１）：０．５０≦ｙＢ≦３．４５
    　式（ｂ１－２）：０．３０ｘＢ－１８．６８≦ｙＢ≦０．２０ｘＢ－０．４８     A heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam,
    The thermal insulation material is a layer in which, when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min, a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b1-1) and formula (b1-2) can be generated.
    Formula (b1-1): 0.50≦y B ≦3.45
    Formula (b1-2): 0.30x B -18.68≦y B ≦0.20x B -0.48
  2. 　前記断熱層が、前記断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ１－１）および下記式（ａ１－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項１に記載の断熱材。
    　式（ａ１－１）：０．５０≦ｙＡ≦３．４５
    　式（ａ１－２）：０．１２ｘＡ－２．４５≦ｙＡ     The heat insulating material according to claim 1, wherein the heat insulating layer is a layer capable of producing a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a1-1) and formula (a1-2) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min.
    Formula (a1-1): 0.50≦y A ≦3.45
    Formula (a1-2): 0.12x A -2.45≦y A
  3. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ２－１）および下記式（ｂ２－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、請求項１または２に記載の断熱材。
    　式（ｂ２－１）：１．００≦ｙＢ≦３．００
    　式（ｂ２－２）：０．２０ｘＢ－１１．００≦ｙＢ≦０．１０ｘＢ     The thermal insulation material according to claim 1 or 2, wherein the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b2-1) and formula (b2-2) when the compression test is performed.
    Formula (b2-1): 1.00≦y B ≦3.00
    Formula (b2-2): 0.20x B -11.00 ≦ y B ≦ 0.10x B
  4. 　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ２－１）および下記式（ａ２－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項２に記載の断熱材。
    　式（ａ２－１）：１．００≦ｙＡ≦３．００
    　式（ａ２－２）：０．２０ｘＡ－３．００≦ｙＡ     The heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a2-1) and formula (a2-2) when the compression test is performed. The heat insulating material according to claim 2.
    Formula (a2-1): 1.00≦y A ≦3.00
    Formula (a2-2): 0.20xA -3.00≦ yA
  5. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ３－１）および下記式（ｂ３－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、請求項３に記載の断熱材。
    　式（ｂ３－１）：１．５０≦ｙＢ≦３．００
    　式（ｂ３－２）：０．１５ｘＢ－７．５０≦ｙＢ≦０．１０ｘＢ－１．００     The thermal insulation material according to claim 3, wherein the buffer layer is a layer that can generate a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b3-1) and (b3-2) when the compression test is performed.
    Formula (b3-1): 1.50≦y B ≦3.00
    Formula (b3-2): 0.15x B -7.50≦y B ≦0.10x B -1.00
  6. 　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ３－１）および下記式（ａ３－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項４に記載の断熱材。
    　式（ａ３－１）：１．５０≦ｙＡ≦２．５０
    　式（ａ３－２）：０．２０ｘＡ－１．５０≦ｙＡ     The heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a3-1) and formula (a3-2) when the compression test is performed. The heat insulating material according to claim 4.
    Formula (a3-1): 1.50≦y A ≦2.50
    Formula (a3-2): 0.20xA -1.50≦ yA
  7. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ４－１）および下記式（ｂ４－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じる層である、請求項５に記載の断熱材。
    　式（ｂ４－１）：２．００≦ｙＢ≦２．５０
    　式（ｂ４－２）：０．１０ｘＢ－３．５０≦ｙＢ≦０．１０ｘＢ－１．５０     The thermal insulation material according to claim 5, wherein the buffer layer is a layer that, when the compression test is performed, produces a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formulas (b4-1) and (b4-2):
    Formula (b4-1): 2.00≦y B ≦2.50
    Formula (b4-2): 0.10x B -3.50≦y B ≦0.10x B -1.50
  8. 　前記断熱層の前記無機粒子が、二酸化ケイ素粒子である、請求項１または２に記載の断熱材。 The insulating material according to claim 1 or 2, wherein the inorganic particles of the insulating layer are silicon dioxide particles.
  9. 前記二酸化ケイ素粒子が、乾式シリカ、湿式シリカ、およびシリカエアロゲルからなる群より選択される少なくとも１種である、請求項８に記載の断熱材。 The heat insulating material according to claim 8, wherein the silicon dioxide particles are at least one selected from the group consisting of dry silica, wet silica, and silica aerogel.
  10. 前記二酸化ケイ素粒子が、親水性フュームドシリカである、請求項８に記載の断熱材。 The insulation material of claim 8, wherein the silicon dioxide particles are hydrophilic fumed silica.
  11. 前記断熱層が、無機粒子および無機繊維を含む混合物を成形した成形体である、請求項１または２に記載の断熱材。 The heat insulating material according to claim 1 or 2, wherein the heat insulating layer is a molded body made by molding a mixture containing inorganic particles and inorganic fibers.
  12. 　バッテリーモジュールまたはバッテリーパックのセル間に配置される、請求項１または２に記載の断熱材。 The insulating material according to claim 1 or 2, disposed between cells of a battery module or battery pack.
  13. 　無機粒子を含んでなる断熱層と、繊維を含んでなる繊維成形体または発泡体を含んでなる発泡成形体からなる緩衝層と、を有する断熱材であって、
    　前記緩衝層が、前記緩衝層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ｂ５－１）および下記式（ｂ５－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、断熱材。
    　式（ｂ５－１）：０．１０≦ｙＢ≦１．３９
    　式（ｂ５－２）：０．１２９ｘＢ－９．５７５≦ｙＢ≦０．１２９ｘＢ－１．１９     A heat insulating material having a heat insulating layer containing inorganic particles and a buffer layer made of a fiber molded body containing fibers or a foam molded body containing a foam,
    The thermal insulation material is a layer in which a compressed state of a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b5-1) and formula (b5-2) can be generated when a compression test is performed on only the buffer layer at a compression speed of 0.5 mm/min.
    Formula (b5-1): 0.10≦y B ≦1.39
    Formula (b5-2): 0.129x B -9.575≦y B ≦0.129x B -1.19
  14. 　前記断熱層が、前記断熱層のみに対して圧縮速度０．５ｍｍ／ｍｉｎの圧縮試験を行ったときに、下記式（ａ４－１）および下記式（ａ４－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項１３に記載の断熱材。
    　式（ａ４－１）：０．１０≦ｙＡ≦１．３９
    　式（ａ４－２）：０．０４３ｘＡ－０．５４５≦ｙＡ     The heat insulating layer is a layer that can produce a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a4-1) and formula (a4-2) when a compression test is performed on only the heat insulating layer at a compression speed of 0.5 mm/min. The heat insulating material according to claim 13.
    Formula (a4-1): 0.10≦y A ≦1.39
    Formula (a4-2): 0.043x A -0.545≦y A
  15. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ６－１）および下記式（ｂ６－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、請求項１３または１４に記載の断熱材。
    　式（ｂ６－１）：０．２０≦ｙＢ≦１．１０
    　式（ｂ６－２）：０．１２ｘＢ－８．８０≦ｙＢ≦０．０３６ｘＢ－０．３４     The thermal insulation material according to claim 13 or 14, wherein the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b6-1) and formula (b6-2) when the compression test is performed.
    Formula (b6-1): 0.20≦y B ≦1.10
    Formula (b6-2): 0.12x B -8.80≦y B ≦0.036x B -0.34
  16. 　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ５－１）および下記式（ａ５－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項１４に記載の断熱材。
    　式（ａ５－１）：０．２０≦ｙＡ≦１．１０
    　式（ａ５－２）：０．０９ｘＡ－１．１５≦ｙＡ     The heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a5-1) and the following formula (a5-2) when the compression test is performed. The heat insulating material according to claim 14.
    Formula (a5-1): 0.20≦y A ≦1.10
    Formula (a5-2): 0.09x A −1.15≦y A
  17. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ７－１）および下記式（ｂ７－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じうる層である、請求項１５に記載の断熱材。
    　式（ｂ７－１）：０．３０≦ｙＢ≦０．９０
    　式（ｂ７－２）：０．１２ｘＢ－８．７０≦ｙＢ≦０．０４ｘＢ－０．９０     The thermal insulation material according to claim 15, wherein the buffer layer is a layer capable of generating a compressed state having a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b7-1) and formula (b7-2) when the compression test is performed.
    Formula (b7-1): 0.30≦y B ≦0.90
    Formula (b7-2): 0.12x B -8.70≦y B ≦0.04x B -0.90
  18. 　前記断熱層が、前記圧縮試験を行ったときに、下記式（ａ６－１）および下記式（ａ６－２）を満たす圧縮ひずみ値ｘＡ［％］と圧縮応力値ｙＡ［ＭＰａ］の圧縮状態が生じうる層である、請求項１６に記載の断熱材。
    　式（ａ６－１）：０．３０≦ｙＡ≦０．９０
    　式（ａ６－２）：０．１２ｘＡ－０．９０≦ｙＡ     The heat insulating layer is a layer that can generate a compressed state of a compressive strain value x A [%] and a compressive stress value y A [MPa] that satisfy the following formula (a6-1) and formula (a6-2) when the compression test is performed. The heat insulating material according to claim 16.
    Formula (a6-1): 0.30≦y A ≦0.90
    Formula (a6-2): 0.12x A -0.90 ≦ y A
  19. 　前記緩衝層が、前記圧縮試験を行ったときに、下記式（ｂ８－１）および下記式（ｂ８－２）を満たす圧縮ひずみ値ｘＢ［％］と圧縮応力値ｙＢ［ＭＰａ］の圧縮状態が生じる層である、請求項１７に記載の断熱材。
    　式（ｂ８－１）：０．４０≦ｙＢ≦０．８０
    　式（ｂ８－２）：０．０８ｘＢ－５．６０≦ｙＢ≦０．０３２ｘＢ－０．８８     The thermal insulation material according to claim 17, wherein the buffer layer is a layer that, when the compression test is performed, produces a compressed state with a compressive strain value x B [%] and a compressive stress value y B [MPa] that satisfy the following formula (b8-1) and formula (b8-2):
    Formula (b8-1): 0.40≦y B ≦0.80
    Formula (b8-2): 0.08x B -5.60≦y B ≦0.032x B -0.88
  20. 　前記断熱層の前記無機粒子が、二酸化ケイ素粒子である、請求項１３または１４に記載の断熱材。 The insulating material according to claim 13 or 14, wherein the inorganic particles of the insulating layer are silicon dioxide particles.
  21. 前記二酸化ケイ素粒子が、乾式シリカ、湿式シリカ、およびシリカエアロゲルからなる群より選択される少なくとも１種である、請求項２０に記載の断熱材。 The heat insulating material according to claim 20, wherein the silicon dioxide particles are at least one selected from the group consisting of dry silica, wet silica, and silica aerogel.
  22. 前記二酸化ケイ素粒子が、親水性フュームドシリカである、請求項２０に記載の断熱材。 The insulation material of claim 20, wherein the silicon dioxide particles are hydrophilic fumed silica.
  23. 前記断熱層が、無機粒子および無機繊維を含む混合物を成形した成形体である、請求項１３または１４に記載の断熱材。 The heat insulating material according to claim 13 or 14, wherein the heat insulating layer is a molded body formed from a mixture containing inorganic particles and inorganic fibers.
  24. 　バッテリーモジュールまたはバッテリーパックのセル間に配置される、請求項１３または１４に記載の断熱材。

          15. The insulation material of claim 13 or 14, disposed between cells of a battery module or battery pack.
PCT/JP2023/038971 2022-10-31 2023-10-27 Heat-insulating material WO2024095930A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015182768A1 (en) * 2014-05-30 2015-12-03 旭硝子株式会社 Vacuum heat-insulating material
JP2017215014A (en) * 2016-06-02 2017-12-07 パナソニックＩｐマネジメント株式会社 Heat insulating material and apparatus using the same
WO2021177205A1 (en) * 2020-03-06 2021-09-10 ニチアス株式会社 Heat insulating material for battery and battery

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015182768A1 (en) * 2014-05-30 2015-12-03 旭硝子株式会社 Vacuum heat-insulating material
JP2017215014A (en) * 2016-06-02 2017-12-07 パナソニックＩｐマネジメント株式会社 Heat insulating material and apparatus using the same
WO2021177205A1 (en) * 2020-03-06 2021-09-10 ニチアス株式会社 Heat insulating material for battery and battery

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