JP2010281444A - Heat insulating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat insulating material having excellent heat insulating performance, easily filled in a clearance by being flexibly brought into close contact in response to a shape of an object, and superior in durability without causing deformation and a thickness change over a long period due to having sufficient form retention. <P>SOLUTION: This heat insulating material is provided by filling gas of heat conductivity lower than nitrogen inside by wrapping a core material 2 being a fiber stacking body and having a void inside with a skin material 1 having gas-barrier performance, and has the gas-barrier performance on which permeability of carbon dioxide of the skin material 1 is 15 ml/m<SP>2</SP>day (a measuring condition of 23°C, 0%RH) or less. As a desirably mode, the fiber stacking body includes fiber having a fiber diameter of 15 μm or less by 70 wt.% or more based on the whole weight of the fiber stacking body. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat insulating material.

Insulation materials are used from the viewpoint of energy saving in places where large amounts of energy are used, such as household electrical appliances such as refrigerators and rice cookers, commercial equipment such as vending machines and cold storage cars, and buildings such as houses, buildings, and cold storage warehouses. Has been. For example, foamed resin heat insulation material (hereinafter referred to as foamed heat insulation material) in which polystyrene, urethane, phenol resin is foamed with chlorofluorocarbon, hydrocarbon, carbon dioxide (carbon dioxide), etc. is used because it has high heat insulation properties. The amount is increasing but relatively expensive.
In addition to the above foam insulation, there is an inorganic fiber insulation that is molded into a nonwoven fabric using phenolic resin as a binder to artificial mineral fibers obtained from glass fibers and steel slag, etc., which is less expensive than foam insulation. Since it is flexible and can be deformed freely, it can be used in various places. However, since the inside of the heat insulating material is air, the performance is low compared to the foamed heat insulating material having low heat conductivity such as chlorofluorocarbon, hydrocarbon and carbon dioxide inside, and there is a problem that the heat insulating material becomes thick to make up for it. there were.

  In recent years, from the viewpoint of global warming prevention and environmental protection, demands for the performance of heat insulating materials are increasing, and vacuum heat insulating materials with higher heat insulating performance are being used in various places. The vacuum heat insulating material is a material obtained by wrapping a core material with an outer skin material and evacuating the inside to achieve a very high heat insulating performance. A void is formed in the inside by using a core material filled with inorganic particles such as pearlite or silica, a resin foam such as a continuous foam of urethane resin, or a nonwoven fabric such as glass fiber. Then, in order to improve the gas barrier property to resin films such as polyester resin, after wrapping the core material with a gas barrier film laminated with metal vapor deposition or metal foil as the outer skin material, heat seal the edge of the outer skin material while decompressing By doing so, it is made hermetically (Patent Documents 1 and 2).

  The vacuum insulation material has a reduced pressure inside, so that it can withstand atmospheric pressure and maintain its thickness, so that the core material has compression resistance, and the outer skin material is in close contact from above and below the core material. The structure becomes very stiff. When the core material is fibrous, such as glass fiber, it is possible to bend the vacuum heat insulating material, but because of its high rigidity, it is difficult to adhere the heat insulating material to curved parts, uneven parts, corner parts, etc. It is. Therefore, there is a problem that a gap is formed between the portion to be insulated and the heat insulating material, and heat loss is generated therefrom. There is also a problem when the vacuum insulation material is discarded. For example, if the core material is an inorganic fiber such as glass fiber, it cannot be incinerated, so it costs to be separated. In the case of a urethane resin, an unhealthy gas may be generated during combustion. It is not preferable for a person. In recent years, polyester fibers are used as the core material (Patent Document 3). In this case, there are few problems at the time of disposal, but synthetic fibers such as polyester fibers are creeped compared to glass wool. Due to inferior characteristics, there is another problem that the thickness is reduced by continuing to receive atmospheric pressure.

  For the purpose of ease of separation and disassembly, a heat insulating material is disclosed in which a thin plate formed by molding a resin in a porous shape is wrapped with a film and filled with carbon dioxide gas or ozone non-destructive gas (Patent Document 4). However, the flexibility to adhere to the shape of the object is poor, there is no disclosure of internal gas leakage prevention means, and there is a problem in durability of heat insulation performance.

  Further, from the viewpoint of improving the heat insulation performance, a method of wrapping a compression plate with a sheet and filling the gas (Patent Document 5), a method of filling and solidifying the fiber in the heat insulating portion of the container, and filling the gas (Patent Document 6) or foaming A method (Patent Document 7) is disclosed in which a heat insulating material is wrapped with a film and filled with gas. However, these heat insulating materials have extremely high rigidity and poor flexibility because the core material or the outer skin material is hard.

JP-A-7-091594 JP 2008-69820 A JP 2008-286282 A JP-A-4-285396 Japanese Patent Laid-Open No. 60-260796 JP-A-6-283217 Japanese Patent Laid-Open No. 7-10338

It is an object of the present invention to have excellent heat insulation performance, be flexible and fit in conformity with the shape of an object, and can be easily filled into a gap, and has sufficient form-retaining properties. It is to provide a heat insulating material excellent in durability without deformation or thickness change over a period of time.

In order to solve this problem, the present invention is characterized by the following configuration.
(1) A heat-insulating material in which a core material having a void inside is wrapped with a skin material having a gas barrier property and filled with a gas having a lower thermal conductivity than nitrogen. Carbon dioxide gas permeability of 15 ml / m ² · day (measuring condition 23 ° C., 0% RH) or less has a gas barrier property.
(2) The fiber assembly includes 70% by weight or more of fibers having a fiber diameter of 15 μm or less with respect to the total weight of the fiber assembly, and a density of 10 kg / m ³ or more and 150 kg / m ³ or less. The said heat insulating material characterized by these.
(3) The heat insulating material according to any one of the above, wherein the fiber aggregate is a fiber aggregate including matrix fibers and binder fibers.
(4) The binder fiber has a core portion made of a thermoplastic resin and a sheath portion made of a thermoplastic resin having a melting point lower than that of the thermoplastic resin of the core portion, and the constituent ratio of the sheath portion is the total of the binder fibers. The said heat insulating material characterized by being 40 to 80 weight% with respect to a weight.
(5) The heat insulating material according to any one of the above, wherein the heat insulating material has a bending strength of 20 N / cm ² or less measured according to JIS K7221-2 (2006).
(6) The gas having a lower thermal conductivity than nitrogen is at least one gas selected from the group consisting of hydrocarbon, carbon dioxide, argon, krypton, and xenon, and the filling concentration of the gas is 30 to 100%. The heat insulating material according to any one of the above, wherein the heat insulating material is any one of the above.
(7) The skin material is a film having a multilayer structure, and is selected from the group consisting of an ethylene vinyl alcohol copolymer, polyamide, polyglycolic acid, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and a fluororesin. The heat insulating material according to any one of the above, wherein the heat insulating material has at least one gas barrier resin film layer made of a resin.
(8) At least one layer of the multilayer structure of the outer skin material is a reinforcing film layer in which a resin selected from the group consisting of polyamide, aromatic polyester, aliphatic polyester, and polyolefin resin is used alone or in combination of two or more. The heat insulating material according to any one of the above, wherein the heat insulating material is any one of the above.
(9) At least one of the gas barrier resin film layer and the reinforcing film layer, or a film layer obtained by laminating the gas barrier resin film layer and the reinforcing film layer is uniaxial or biaxial with an area magnification of 2.0 times or more. The heat insulating material according to any one of the above, wherein the heat insulating material is a stretched film layer.
(10) The heat insulating material according to any one of the above, wherein at least one layer of the outer skin material is formed of a vapor deposition layer selected from a metal or a metal oxide.

  According to this invention, it has the outstanding heat insulation performance and can become flexible. As a result, it is easy to make it closely adhere to the shape of the heat insulation object or to fill the gap. Moreover, since it has sufficient form retentivity, it is possible to provide a heat insulating material with excellent durability that is free from deformation and thickness change over a long period of time. The heat insulating material of the present invention can be suitably used as a heat insulating material for buildings such as home appliances, industrial machines, and houses.

It is the schematic of the cross section of the heat insulating material produced in the Example of this invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  The heat insulating material of the present invention is characterized in that a core material having a void inside is wrapped with a skin material having a gas barrier property, and the inside of the skin material is filled with a gas having a lower thermal conductivity than air.

The gas filled inside is selected from gases having lower thermal conductivity than nitrogen. The thermal conductivity of nitrogen is 26.5 mW / m · K (at 298 K, 101 kPa, the thermal conductivity of the gas described below is the same temperature and pressure conditions), and the average thermal conductivity of air is 26. It is almost the same as 6mW / m · K. By filling the inside of the heat insulating material with a gas having a lower thermal conductivity than nitrogen, the heat insulating performance of the heat insulating material is improved. Any gas that has a lower thermal conductivity than nitrogen can be used.
Halogen compounds such as chlorofluorocarbon gas have lower thermal conductivity than nitrogen and can be used, but are not preferable because they are considered to be one of the causative substances of global warming. Gases that can be preferably used in the present invention and can be obtained industrially at low cost include hydrocarbons such as isobutane (16.3 mW / m · K), carbon dioxide (16.8 mW / m · K), and argon (18.01 mW). / M · K), krypton (9.4 mW / m · K), and xenon (5.6 mW / m · K). Among them, carbon dioxide gas and rare gas are non-flammable gases, and are safe and preferable because they have the effect of preventing the spread of fire when the heat insulating material is ignited. Among them, a heat insulating material using carbon dioxide gas or argon gas is industrially inexpensive and is most suitable for a heat insulating material for a house where a low price is required. In addition, heat insulating materials using krypton gas and xenon gas have low thermal conductivity, and are optimal for residential heat insulating materials, household electric appliances, and industrial heat insulating materials that require high performance. In the present invention, a gas having a lower thermal conductivity than nitrogen is referred to as a “low thermal conductivity gas”. Since the heat insulation performance of a heat insulating material becomes high, so that the density | concentration of low heat conductivity gas is high, 100% is preferable. However, it is expensive to replace the interior with a filling gas when manufacturing the heat insulating material. The concentration at which both performance and cost are industrially compatible is preferably 30% or more. More preferably, it is 80% or more. If the concentration of the low thermal conductivity is less than 30%, heat conduction of air remaining inside the heat insulating material is large, and sufficient heat insulating performance cannot be obtained.
The filling amount of the low thermal conductivity gas is preferably such that the internal pressure is almost the same as the atmospheric pressure. Since the atmospheric pressure differs slightly depending on the location and temperature, it is determined in consideration of the location and temperature range to be used. If the internal pressure greatly exceeds the atmospheric pressure, the heat insulating material swells, making it difficult to bend or deform the heat insulating material, resulting in the worst burst. If the internal pressure is reduced to less than atmospheric pressure, the heat insulating material may be compressed by atmospheric pressure. In addition, the gas filling concentration in the present invention is based on the method described in the measuring methods (1) and (2) in the column of Examples described later, but any measuring device can be used as long as it can perform the same measurement. There may be.

  The skin material of the heat insulating material of the present invention has a thickness of 50 to 400 μm. If the thickness is 50 μm or less, the strength is not sufficient, and there is a possibility that it will be broken during use. On the other hand, if it is 400 μm or more, the rigidity becomes high, the flexibility of the heat insulating material is lost, and it becomes difficult to use.

The skin material of the present invention has a carbon dioxide permeability of 15 [ml / m ² · day · atm (23 ° C., 0% RH)] or less as measured based on the gas chromatographic method described in JIS K7126-2 (2006). It is. When the carbon dioxide permeability exceeds 15 [ml / m ² · day · atm (23 ° C, 0% RH)], the gas filled inside is replaced with air at an early stage. The period will be shortened. Furthermore, when the heat insulating material usage period is required for 10 years or more, preferably, the carbon dioxide permeability is 5 [ml / m ² · day · atm (23 ° C., 0% RH)] or less, and when used for a long time The carbon dioxide permeability is preferably 0.1 [ml / m ² · day · atm (23 ° C., 0% RH)] or less. Carbon dioxide gas has a very high affinity for resins and is more permeable than other gases, so even if the gas that fills the inside of the heat insulating material is other than carbon dioxide, the film performance is above the above performance. If you can, you can use it. The carbon dioxide permeability in the present invention is based on the method described in the measurement method (3) in the column of Examples described later, but the measurement device may be any device as long as it can perform an equivalent measurement. .
More preferably, the outer skin material of the present invention has a water vapor transmission rate of 5.0 [g / m ² · day] or less measured based on the infrared sensor method described in JIS K7129 (2008). Water has a very high thermal conductivity, and if water vapor enters the heat insulating material, the heat insulating performance is extremely lowered. In addition, although the water-vapor-permeation rate in this invention is based on the method described in the measuring method (3) of the column of the Example mentioned later, as long as a measuring apparatus can perform an equivalent measurement, what kind of apparatus may be sufficient as it.
In order to achieve the above performance, the outer skin material of the present invention is preferably a film having a multilayer structure.
Further, in the outer skin material of the present invention, at least one layer of the multilayer structure is preferably a resin film layer having a high gas barrier property. Resins with high gas barrier properties include ethylene vinyl alcohol copolymer, polyamide, polyglycolic acid, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), fluorine resin, etc. It is recommended to use a resin having a small size. Among these, polyglycolic acid, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and fluorine-based resin are preferable because they have low hygroscopicity and extremely low humidity dependency of gas barrier properties. Furthermore, two or more layers of one kind of resin film selected from the above resins can be laminated in order to improve gas barrier properties. It is also possible to select two or more types of resins and to laminate a plurality of layers. The gas barrier resin film layer described above is referred to as a “gas barrier resin film layer” in the present invention.
In addition to the gas barrier resin film layer, the outer covering material of the present invention is laminated with a resin film in which at least one selected from the group consisting of polyamide, aromatic polyester, aliphatic polyester and polyolefin is blended. Is preferred. The resin is excellent in strength, weather resistance, and chemical resistance, and can reinforce and protect the gas barrier film resin film layer. The film layer described above is called a “reinforcing film layer” in the present invention.
The film constituting the skin material of the present invention, that is, the gas barrier resin film and the reinforcing film layer, is preferably stretched uniaxially or biaxially by 2.0 times or more in area magnification. More preferably, it is preferably biaxially stretched at an area magnification of 4.0 times or more. By stretching the film, the regularity of the polymer main chain of the film increases, the interaction between the polymer main chains increases, and the free volume decreases. That is, the gas barrier property of the gas barrier resin film layer is improved, and the strength and durability of the reinforcing film layer are improved. The method of stretching the film is to stretch the film in the direction of travel (longitudinal direction) by passing the film between rolls with a difference in speed, and then holding the both ends of the film in the width direction and stretching in the width direction. Examples include sequential biaxial stretching, and simultaneous biaxial stretching in which the film is blown into a tube shape to simultaneously stretch in the longitudinal direction and the width direction. Stretching of the film layer may be performed after the gas barrier resin film layer and the reinforcing film layer are laminated, or may be laminated on the other film layer after stretching one film layer alone, These film layers may be laminated after being stretched separately.
The outer skin material of the present invention preferably has a vapor deposition layer in which at least one layer is selected from metals or metal oxides. A gas barrier property improves by having a vapor deposition layer. As a method for improving the gas barrier property, a method of laminating a metal foil on a film is also possible. However, since the metal foil is thick and hard, the flexibility of the outer skin material and the heat insulating material is impaired, and thus a vapor deposition layer is preferable. More preferably, it is preferably deposited on at least one side of the gas barrier resin film layer. When the vapor deposition layer contacts the gas barrier resin film layer, the gas barrier property can be improved and the gas barrier resin film layer can be protected by the vapor deposition layer. Deposition is performed after stretching of the film layer.
Examples of the metal used for the vapor deposition layer include aluminum, indium, zinc, gold, silver, platinum, nickel, and chromium. Examples of the metal oxide used for the vapor deposition layer include oxides such as titanium, zirconium, silicon, and magnesium. Among them, aluminum that has low permeability to carbon dioxide gas and water vapor and is widely used is preferably used.
As a vapor deposition method of metal or metal oxide, a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, a physical vapor deposition method such as an ion plating method, or a chemical vapor deposition method such as plasma CVD can be used. From this point of view, the vacuum deposition method is particularly preferably used.
When laminating a vapor deposition layer, it is preferable to perform a pretreatment such as a corona discharge treatment on the vapor deposition surface of a resin film serving as a substrate in advance in order to improve the adhesion of the vapor deposition film.
Moreover, when forming a vapor deposition layer, it is also preferable to apply | coat a primer agent in-line or offline beforehand on the film used as a base material. It is preferable to provide a primer agent coating layer because a vapor-deposited film having high adhesion can be obtained and effective in improving gas barrier properties.
More preferably, it is desirable to heat-treat at 150 ° C. or higher after forming a deposited layer of the outer skin material. By heat-treating, the affinity between the vapor deposition layer and the film can be increased, and cracking or peeling of the vapor deposition layer can be prevented when the heat insulating material is manufactured or used.
The outer skin material of the present invention may be a laminate of a plurality of films having the same configuration or different configurations described above.
It is preferable to have a heat seal layer on at least one surface of the outer skin material of the present invention. Since the outer skin material has a heat seal layer, the heat seal layer can be used to manufacture a bag at the time of manufacturing the heat insulating material, or to bond the outer periphery of the outer skin material after wrapping the core material with the outer skin material. As a result, the production can be made efficient and the sealing performance of the heat insulating material can be improved. The method for forming the heat seal layer is not particularly limited, but the method of laminating the heat sealable resin by the extrusion lamination method is low cost. As the heat sealable resin constituting the heat seal layer, a thermoplastic resin can be preferably used. For example, a low density polyethylene resin (LDPE), a linear low density polyethylene resin (LLDPE), an ethylene / propylene copolymer, an ethylene / propylene copolymer, Polyolefin resins such as methacrylic acid copolymer (EMAA), ethylene / vinyl acetate copolymer, ethylene / α-olefin copolymer, unstretched polypropylene (CPP), biaxially stretched polypropylene (OPP), and biaxially stretched polyester (OPET), pan acrylic (PAN), vinylidene chloride (PVDC), ethylene vinyl alcohol (EVOH), polyvinyl alcohol (PVA), polychlorotrifluoroethylene copolymer (CTFE), etc. are exemplified, depending on use conditions such as temperature Select and use Door can be.
The core material of the present invention uses a material having a void inside. Anything having voids can be used. For example, a method of filling an outer powder with inorganic powder, a continuous foamed resin foam, and a fiber aggregate such as a woven fabric, a knitted fabric, and a non-woven fabric can be used. Nonwoven fabrics are preferred among the fiber aggregates, and fiber molded bodies are preferred because they are flexible and excellent in shape retention.
Nonwoven fabrics such as spunbond (long fiber) nonwoven fabrics and short fiber nonwoven fabrics can be used as the fiber assembly, but nonwoven fabrics composed of short fibers are particularly preferable because the thickness and density can be freely designed.
Short-fiber non-woven fabrics include needle-punched non-woven fabrics that are entangled with needle punches and molded into sheets, and chemical-bond non-woven fabrics that form fibers using resin binders. Although it is easy to manufacture, there is a place where it is difficult to manufacture a nonwoven fabric of 10 mm or more and fine thickness control is difficult. Moreover, since the outgas from binder resin generate | occur | produces, a chemical bond nonwoven fabric is not without the possibility of having a bad influence on the heat insulation performance of a heat insulating material. Accordingly, the fiber aggregate in the present invention is most preferably a non-woven fabric produced by thermoforming a matrix web and a binder fiber that are opened, mixed, and formed into a card web.
The fiber aggregate obtained by the production method can be adjusted in thickness and elasticity by a combination of fiber type, fineness, and density.

The fiber assembly used for the core material of the present invention preferably contains 70% by weight or more of fibers having a fiber diameter of 15 μm or less with respect to the total weight of the fiber assembly. More preferably, it contains 70% by weight or more of fibers of 12 μm or less with respect to the total weight of the fiber assembly. By including 70% by weight or more of the fiber diameter in the range described above, the gap between the fibers is miniaturized, and both heat transfer by radiation and heat transfer by convection of the filling gas in the heat transfer inside the heat insulating material. It becomes possible to suppress, and heat insulation performance can be improved. Here, when the cross section of the fiber is not circular, the diameter of the circumscribed circle in the observed state is adopted as the fiber diameter. Furthermore, the density of the fiber aggregate is preferably 10 kg / m ³ or more and 150 kg / m ³ or less. More preferably, it is 10 kg / m ³ or more and 50 kg / m ³ or less. When the density is low, the gap between the fibers becomes large, and the effect of suppressing the radiation and convection of the fibers is not sufficiently exhibited. On the other hand, if the density is high, the effect of suppressing the radiation and convection of the fiber due to the increase in density is improved, but the amount of heat transmitted through the fiber itself is increased rather than the effect of suppressing the radiation and convection of the fiber, and the heat insulation performance tends not to be improved. It is in.
The characteristics of the matrix fibers and the binder fibers and the production method and form of the fiber assembly are shown below.
(Matrix fiber)
The average fiber diameter of the matrix fibers used in the present invention is preferably 15 μm or less. When the fiber diameter of the binder fiber described later is large, the matrix fiber having the average fiber diameter shown above is contained by 70% by weight or more with respect to the total weight of the fiber assembly. In order to obtain the further improvement effect of the heat insulation performance by refining the space between the fibers, the average fiber diameter is preferably 12 μm or less.
As the matrix fiber used in the present invention, various fibers such as inorganic fibers such as glass fibers, artificial mineral fibers, and metal fibers, synthetic fibers, and natural fibers can be used. In order to stably obtain a fiber having a small diameter and a small fiber diameter, it is preferable to use a synthetic fiber.
Synthetic fibers include, for example, polyester (polyethylene terephthalate, polybutylene terephthalate, polylactic acid, etc.) fiber, polyolefin (polyethylene, polypropylene), polyamide (nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 510, etc.) There are synthetic fibers such as fibers, polyacetal fibers, acrylic fibers, modacrylic fibers, aramid fibers, fluorine fibers, and carbon fibers, and regenerated fibers such as rayon. These one or more types of fibers can be used in combination.

  Polyester (polyethylene terephthalate, polybutylene terephthalate, polylactic acid, etc.) fiber (official moisture content 0.5%), which has high versatility and has an official moisture content of 1% or less and less concern about deterioration of heat insulation performance due to moisture, Or, polyolefin (polyethylene, polypropylene) fiber (official moisture content 0%) is preferably used. In particular, it is preferable to use a polypropylene fiber (thermal conductivity 0.12 W / m · K) that has a low thermal conductivity of the material itself and a good thermal insulation performance in view of the thermal insulation performance.

  Moreover, in order to reduce the fiber diameter of the fiber, it is also possible to use a split composite fiber, for example, a split composite fiber made of polyester and polyamide, or a split composite fiber made of polyethylene and polypropylene, or polypropylene and polyester. It is done. These fibers are divided in the production process of the fiber assembly, divided into ultrafine fibers having a diameter of about 1 to 10 μm, and are preferably used for improving the heat insulation performance.

  In addition, for the purpose of improving the long-term shape retention of the heat insulating material, a highly rigid hollow cross-section fiber or irregular cross-section fiber can be blended. For example, a multi-lobe cross section such as a hollow cross section, a porous hollow cross section, a trilobal cross section (triangular cross section, Y cross section, T cross section, etc.), flat cross section, W cross section, X cross section, etc. can be employed.

  Among these, hollow fibers are preferably used because they contain gas in the fibers and suppress convection of the contained gas, thereby improving the heat insulation performance.

The matrix fiber of the fiber assembly in the present invention preferably has crimps. By doing so, bulkiness improves in a heat insulating material, and it is excellent in heat insulation performance and form retainability. Further, in the carding method, the needle is firmly caught and uniformly dispersed and intertwined with other fibers, so that a stable and high yield fiber assembly can be obtained.
The average fiber length of the matrix fibers is preferably 10 to 90 mm. Bonding matrix fibers having a fiber length of 10 mm or more with binder fibers is preferable because the rigidity of the fiber assembly can be increased and shape retention can be obtained. On the other hand, by setting the fiber length to 90 mm or less, the matrix fiber and the binder fiber are uniformly dispersed and finely entangled in the fiber dispersion manufacturing process, that is, the fiber dispersion process such as the carding method or the airlaid method. It is possible to obtain a heat insulating material that has excellent voids and has excellent heat insulating performance.
(Binder fiber)
The binder fiber used in the present invention is a fiber containing a lower melting point component than the matrix fiber. It is important that the binder fiber is firmly bonded to a part between the matrix fiber and the fiber in the fiber aggregate by applying heat at the time of forming the fiber aggregate. Can get.
More preferable binder fibers include, for example, a core-sheath composite fiber and a side-by-side fiber. Among them, it is preferable to use a core-sheath composite fiber in which the sheath component is a thermoplastic resin having a lower melting point than the matrix fiber, and the core component is a thermoplastic resin having a higher melting point than the sheath component. By doing so, the shape of the sheath collapses due to heat at the time of molding, and the fibers of the thin core part remain, so that a more dense structure can be formed in the matrix fiber, and fine voids can be created, so heat insulation performance Thus, a heat insulating material having excellent shape retention can be obtained.
Examples of the constitution of the binder fiber used in the present invention include low melting point polyester and homopolyester, polyolefin and polyester, polyethylene and polypropylene, and the like. As the low melting point polyester, a polyester obtained by copolymerizing polyethylene terephthalate with diethylene glycol or isophthalic acid can be used.
Here, it is preferable that the composition ratio of the sheath portion constituting the binder fiber is 40 to 80% by weight with respect to the total weight of the binder fiber because excellent heat insulation performance and long-term shape retention can be obtained. By making the composition ratio of the sheath part 40% by weight or more, the matrix fibers are firmly bonded to each other, and excellent shape retention is obtained. Furthermore, the fiber diameter of the remaining core portion is reduced, and fine voids are obtained, improving the heat insulating performance. On the other hand, by setting it to less than 80% by weight, it is possible to prevent the fusion with a conveyor or the like at the time of molding and to manufacture efficiently.
In addition, by using binder fibers having an average fiber diameter of 15 μm or less in the core portion remaining in the fiber form, the effect is exhibited together with the fine structure of the matrix fibers, and the fiber aggregate has a dense structure and a fine void is formed. A heat insulating material with excellent performance can be obtained.

The binder fiber used in the present invention is preferably 10% by weight or more and less than 60% by weight as a whole of the fiber laminate from the viewpoint of shape retention. By setting it as 10 weight% or more, matrix fibers are couple | bonded and the effect of form retention property is acquired. On the other hand, when the content is less than 60% by weight, fusion with a conveyance conveyor or the like at the time of molding can be prevented and production can be efficiently performed.
Like the matrix fiber, the binder fiber used in the present invention preferably has crimps, and the average number average fiber length is preferably 10 to 90 mm.
(Fabric assembly manufacturing method)
In the fiber aggregate of the present invention, it is preferable that the matrix fiber and the binder fiber are mixed, the web is laminated by the carding method or the airlaid method after the fiber opening, and the heat treatment is performed. By this carding method or airlaid method, an aggregate in which matrix fibers and binder fibers are uniformly dispersed can be produced. The heat treatment temperature is higher than the temperature at which the low melting point component in the binder fiber softens or melts, and lower than the temperature at which the other components melt. As a result, the low melting point component is softened or melted, and the matrix fibers can be firmly held together, and the heat insulating material is excellent in long-term shape retention. As a heat treatment method, a hot air dryer, a hot air circulation heat treatment machine, an infrared heater, a hot roll, or the like is used.

  The density adjustment method can determine the amount of lamination depending on the feed rate in the web lamination process, and further, by adjusting the web thickness with a roll before the heat treatment process, a uniform fiber aggregate is obtained. be able to.

Preferably, in the above-described production process, one or both surfaces of the fiber laminate can be fused and bonded to each other using a heating roller, a hot plate press, or the like. As a result, a dense fiber layer can be formed on the surface of the fiber laminate, and convection between the gas contained in the heat insulating material and the external gas can be suppressed, and the heat insulating performance can be improved. Further, the dense fiber layer can be used as an aggregate of the heat insulating material to enhance the shape retention.
An example of the form of the heat insulating material and the manufacturing method of the present invention will be described below.

The heat insulating material of the present invention is configured by wrapping a core material with an outer skin material and filling the inside with a low thermal conductivity gas.
As an example of the manufacturing method of the heat insulating material of the present invention, a bag body is produced with an outer skin material, a core material is put therein, the inside is replaced with a low heat conduction gas, and finally the opening of the bag body is closed. The sealing method can be adopted.
As a method of manufacturing a bag body with an outer skin material, two outer skin materials having the same shape and size are laminated and two or three sides thereof are bonded together, or the outer skin material is folded in half, and one side or two of the outer skin materials are laminated. A method of adhering sides can be adopted. As a method for adhering the skin material, a method in which a heat seal layer is provided on the surface of the skin material in advance and heat sealing or a method of attaching with an adhesive can be employed. The adhesive used here is not particularly limited, but an adhesive having low adhesive strength and gas permeability is preferable. An example thereof is an adhesive for dry lamination. As the adhesive for dry lamination, a two-component type curing type or thermosetting type adhesive such as vinyl type, acrylic type, polyamide type, polyester type, polyether type, polyurethane type, and epoxy type can be used.
As a method of wrapping the core material with the bag body, a method of manufacturing a bag body from an outer skin material in advance and inserting the core material into the bag body or a method of closing the opening after wrapping the core material with the outer skin material is also adopted. can do. As a method of closing the opening after wrapping the core material with the outer skin material, an overwrapping machine such as a horizontal bag making filling machine, a three-side seal packing machine, or a four-side seal packing machine can be used.
As a method of filling the inside of the heat insulating material with the low thermal conductivity gas, the pipe for supplying the low thermal conductivity gas is inserted into the bag body containing the core material, and the low thermal conductivity gas is blown into the inside air. The method of substituting is preferable. When blowing the low thermal conductivity gas inside the bag body, a method of sucking the internal air from the same place where the pipe for supplying the low thermal conductivity gas of the bag body is inserted, or from one or more different places, or a core material After compressing the encapsulating bag body and extruding the air inside, using a method such as releasing the compressive force and blowing low thermal conductivity gas at the same time can quickly replace the inside of the heat insulating material with low thermal conductivity gas. It is preferable because it is possible. After the low thermal conductivity gas inside the heat insulating material reaches a desired concentration, a sealed structure can be made by bonding all the outer circumferences of the outer skin material.

The heat insulating material of the present invention thus obtained has excellent heat insulating performance and excellent flexibility, and as a result, the bending strength can be 20 N / cm ² or less. As a result, it is easy to closely adhere to the shape of the heat insulation object or to fill the gap. In terms of workability such as close contact and filling in the gap, the bending strength is more preferably 15 N / cm ² or less, and further preferably 10 N / cm ² or less. Moreover, since it has sufficient form-retaining properties, it has excellent durability with no deformation or thickness change over a long period of time, and can be suitably used as a heat insulating material for buildings such as home appliances, industrial machines, and houses.

[Measuring method]
(1) Carbon dioxide concentration inside the heat insulating material Analyzed and measured by a GC / MS apparatus equipped with a head space analyzer. Helium gas having a purity of 99.8% was used as the carrier gas.
(I) The peak of the carrier gas helium was detected as the baseline, and the peak area (BPh) was calculated.
(Ii) Next, 5 cm or more of a sampling needle was inserted in the most longitudinal direction of the heat insulating material, and 5 mL of gas inside the heat insulating material was sampled.
(Iii) Sampling gas was mixed with helium carrier gas and injected into the column of the GC / MS apparatus.
(Iv) Helium, nitrogen, oxygen, hydrocarbon, and carbon dioxide peaks are detected by MS analysis of gas separated by GC, and the peak areas (helium: Ph), (nitrogen: Pn), (oxygen) are detected. : Po), (hydrocarbon-based: Phc), and (carbon dioxide: Pc).
(V) The concentration of carbon dioxide in the heat insulating material was calculated from the obtained peak area by the following formula.
Carbon dioxide concentration [%] = {Pc / (Ph−BPh + Pn + Po + Phc + Pc)} × 100.
(Vi) The number of samples to be measured was 5 samples (n = 5), and the average of 5 times was the carbon dioxide gas concentration.
(2) Measurement of filling gas concentration when filled with other than carbon dioxide gas With an oxygen concentration meter (XO-326ALB, manufactured by New Cosmos Electric Co., Ltd.), the oxygen concentration in the atmosphere and the oxygen concentration inside the heat insulating material are measured. It calculated | required with the following formula | equation.
[Filled gas concentration (w%)] = 100− [Oxygen concentration inside heat insulating material (w%)] ÷ [Oxygen concentration in air (w%)] × 100
(3) Measurement of carbon dioxide gas permeability and water vapor permeability of outer skin material Gas permeation rate measuring device (based on gas chromatograph method described in JIS K7126-2 (2006) under conditions of temperature 23 ° C. and humidity 0% RH ( Carbon dioxide permeability was measured using GL Science (GPM-250). The measurement was performed twice, and the average value of the two measured values was taken as the value of carbon dioxide gas permeability.

Further, based on the infrared sensor method described in JIS K7129 (2008) under the conditions of a temperature of 40 ° C. and a humidity of 90% RH, a moisture permeability measuring device (MOCON, USA: “Permatran” (“PERMATRAN-”) The water vapor transmission rate was measured using W3 / 31 ")). The measurement was performed twice, and the average value of the two measurements was taken as the value of water vapor transmission rate.
(4) Average fiber diameter (when the core is a fiber aggregate)
Measured according to JIS A 9504: 2001 6.7.
The fiber diameter is about 20g from each of the three heat insulating materials, and 20 fibers are taken from each, and the outer diameter (diameter of circumscribed circle) is measured with a magnifying glass using a scanning electron microscope. Values were taken (n = 60). The fiber diameter was measured with an accuracy of 0.1 μm.
(5) Density (when the core material is a fiber aggregate)
Measured according to JIS A 9504: 2001 6.4.2.3.
Density is obtained by the following equation by determining the mass and volume of the sample. The density was determined by calculating the average value of the number of tests 3 times, and the volume and mass were similarly measured and calculated 3 times.
p = m / V
Here, p: density (kg / m ³ )
m: mass (kg)
V: Volume (m ³ )
The volume was obtained from the following formula.
V = t × w × L
Where t: thickness (mm)
w: Width (mm)
L: Length (mm).
The thickness was measured by the following method. First, a 450 × 450 mm test piece is placed on a hard flat plate, and a rigid load plate with a mass of 100 g and 150 × 150 mm is used inside 100 mm or more from the end of the test piece, and through a hole formed in the center of the load plate. A needle-shaped object was inserted, and measurement was made after 1 minute or more had elapsed and the settlement of the load plate stopped. The needle-shaped object was inserted after placing the load plate. In addition, what was compressed and packed was measured after 4 hours passed by the above-mentioned method, holding both ends in the width direction of the sample by hand, shaking well so as to wave in the horizontal direction, and placing on a hard plate.
The mass was measured to an accuracy of 0.1 g with an electronic balance after leaving the test sample used for thickness measurement in a standard state of a temperature of 20 ° C. and a humidity of 65% RH for 24 hours.

(6) Melting point Using a Shimadzu differential scanning calorimeter DSC-60 manufactured by Shimadzu Corporation, 2.0 mg of the sample was measured at a heating rate of 20 ° C./min, and the extreme value of the obtained melting endotherm curve was given. The temperature was the melting point (° C.). The number of tests was 5, and the average value was calculated.
(7) Thermal conductivity It measured according to JIS A 1412-2: 1999 6.2.
The thermal conductivity was measured using a thermal conductivity measuring device HC-074 manufactured by Eihiro Seiki Co., Ltd. The sample size prepared the heat insulating material of width 200mm, length 200mm, and thickness 50mm. As the standard sample, expanded polystyrene was used. The sample is allowed to stand for 24 hours in a standard condition of a temperature of 20 ° C. and a humidity of 65% RH, and then the sample is put into a measuring machine, and the temperature difference of the plate is 24 ° C. and the average temperature is 25 ° C. Was measured under the condition of 13 ° C.), and the thermal conductivity (W / m · K) was calculated from the average value of three test times.
(8) Durability of the heat insulating material When the low heat transfer rate gas is diffused from the inside of the heat insulating material, the thermal conductivity is lowered. In the acceleration test, it was confirmed that the low thermal conductivity gas was difficult to diffuse from the skin material.

After exposing the heat insulating material to an atmosphere of temperature 60 ° C. and humidity 15% RH for 120 hours, the thermal conductivity is measured under the same conditions as the above (1), and the increase in thermal conductivity is less than 20%. The above was determined as x.
(9) Shape retainability of the heat insulating material The shape retaining property is that the heat insulating material having a width of 300 mm, a length of 300 mm, and a thickness of 50 mm is mounted on two pillars (50 mm square) with an interval of 260 mm, and the top of the pillar and the heat insulating material. The difference in the length of the lowermost part (deflection part) was measured to obtain the deflection length. Three samples were evaluated in the width direction and the length direction, respectively, and the average value was calculated. The determination was performed as follows.
Judgment ◯: Deflection length is less than 10 mm Δ: Deflection length is 10 mm or more and less than 20 mm x: Deflection length is 20 mm or more.

(10) Flexibility “Bending strength” was measured according to JIS K7221-2 (2006). Three samples each having a width of 25 mm, a length of 120 mm, and a thickness of 20 mm were taken in each of the vertical direction and the horizontal direction. Using a Shimadzu Corporation autograph (AG-50kG), the maximum point of bending strength was measured at a distance between supporting points of 100 mm and a bending speed of 10 mm / min, and an average value of 6 pieces was calculated. The determination of flexibility was performed as follows.

Judgment ○: Bending strength 20 N / cm ² or less ×: Bending strength exceeding 20 N / cm ²

[Examples 1-7]
(Skin material)
Next, a polyethylene terephthalate resin (“Mitsui PET J120” manufactured by Mitsui Chemicals, Inc.) and polybutylene terephthalate (“1200S” manufactured by Toray Industries, Inc.) were fed into an extruder A provided with a two-layer laminated pinole immediately before the T-die. The pellets were mixed and supplied at a weight ratio of 40:60. Next, a polyglycolic acid resin (prepared as in Note 1 below) was supplied to the extruder B connected to the pinole by a short tube. Extruders A and B were heated to 160 to 280 ° C. and 160 ° C. to 240 ° C., respectively, and extruded from the T die into a sheet shape so that the lamination ratio (thickness) was 4: 1. . The extruded sheet is wound around a mirror drum having a temperature of 20 ° C. to be cooled and solidified, stretched three times in the longitudinal direction using a stretching roll having a preheating temperature of 50 ° C. and a stretching temperature of 55 ° C., and then a preheating temperature of 50 ° C. The film was stretched 3 times in the width direction using a tenter having a stretching temperature of 53 ° C. Next, heat treatment was carried out at 180 ° C. for 10 seconds while giving 5% relaxation in the width direction to obtain a biaxially stretched film.

The film was wound by applying a corona discharge treatment at 30 W · min / m ² while maintaining the film temperature at 55 ° C. in an atmosphere of a mixed gas of nitrogen and carbon dioxide (carbon dioxide concentration ratio: 15 vol%). It set in the vacuum evaporation apparatus which equipped the film travel apparatus, and after making it the high pressure reduction state of 1.00 * 10 ^<-2 > Pa, it was made to travel through a 20 degreeC cooling metal drum. At this time, aluminum (“High-Purity Aluminum Wire” manufactured by Nippon Light Metal Co., Ltd.) was evaporated by heating to form a deposited thin film layer on the surface on which the resin polyglycolic acid resin was laminated. After vapor deposition, the inside of the vacuum vapor deposition apparatus was returned to normal pressure, and the wound film was wound up and aged at a temperature of 40 ° C. for 2 days to obtain a resin film with a vapor deposition layer. The optical density of the metal layer was confirmed in-line during vapor deposition, and the optical density was controlled to be 2.5. The thickness of the obtained resin film with a vapor deposition layer was 20 micrometers.

  An acrylonitrile-based coating agent was applied as a primer to the resin surface opposite to the metal vapor deposition surface of the obtained resin film, and a 15 μm-thick polypropylene film (“Torphan” (registered trademark) manufactured by Toray Industries, Inc.) was applied to the metal vapor deposition surface. ) BO) was laminated on the resin surface with a polyethylene film having a thickness of 50 μm (“Tretec” (registered trademark) manufactured by Toray Industries, Inc.) to form an outer skin material having a thickness of 85 μm.

(Note 1: Preparation method of polyglycolic acid resin)
A 70% glycolic acid aqueous solution was heated to 180 ° C. under a nitrogen stream, and then gradually reduced in pressure to 1.0 × 10 ⁻² MPa to concentrate glycolic acid. When about 30% by weight of water was distilled out with respect to the amount of glycolic acid aqueous solution, about 0.14% of triphenyl phosphite was added with respect to the amount of glycolic acid aqueous solution. After 5 minutes, antimony trioxide and ethylene glycol were added in an amount of about 0.13% and 0.57%, respectively, with respect to the amount of glycolic acid aqueous solution. ^{When the} reaction product started to solidify at ⁻⁴ MPa, the stirring rod was raised above the reaction liquid surface, and the reaction was further performed until the reaction product was completely solidified. After completion of the reaction, the reaction product was cooled to room temperature under a nitrogen atmosphere and pulverized to a powder state. This finely divided low polymer was subjected to a polycondensation reaction at 200 ° C. and 5.0 × 10 ⁻⁴ MPa for 40 hours to obtain a light yellow polyglycolic acid which was hardly colored. The obtained polyglycolic acid was used as a phenol / 2,4,5-tetrachlorophenol mixed solvent (10/7 (weight ratio)) solution having a concentration of 0.5 g / dl at 30.0 ± 0.1 ° C. Using an Ubbelohde viscometer, ηsp / C was determined to be 0.63. Further, from ¹ H-NMR analysis of this polymer, it was confirmed that 0.004 mol of ethylene glycol unit was contained in 1 mol of glycolic acid unit in the molecular chain of the polymer.

(Core material)
A fiber assembly was produced by the following method.

  Polyethylene terephthalate short fibers (Toray Co., Ltd. “Tetron” (registered trademark)) having an average fiber length of 35 mm, a single fiber fineness of 0.8 dtex, and a fiber diameter of 10 μm were prepared as matrix fibers. Further, as a binder fiber, a core-sheath composite fiber (sheath component: low melting point polyethylene terephthalate (sheath component: low-melting polyethylene terephthalate) having an average fiber length of 51 mm, a single fiber fineness of 2.2 dtex, a fiber diameter of 14.2 μm, and a core fiber diameter of 10.0 μm. Melting point 110 ° C.), core component: homopolyethylene terephthalate (melting point 255 ° C.), sheath ratio 50% by weight, Toray Industries, Inc. “Safmet” (registered trademark) T9611).

First, a uniform web was formed by mixing and opening using a card machine so that the mixing ratio of the matrix fiber and the binder fiber was 80:20. Next, the web was laminated so that the mass per unit area was 0.5 to 5.0 kg / m ^2, and sandwiched between two perforated iron plates with a spacer having a thickness of 50 mm, and a hot air dryer ( And heated for 20 minutes at a set temperature of 170 ° C. to melt the binder fiber, and as shown in Table 1, a fiber aggregate having a density of 10 to 100 kg / m ³ and a thickness of 50 mm was formed for each example. .

(Low thermal conductivity gas)
Carbon dioxide was used. The filling concentration was as shown in Table 1.

(Insulation material)
A heat insulating material having a size of 300 × 300 mm × thickness of 50 mm was produced by the following method.
Two skin materials were cut into a size of 370 × 370 mm, and the surfaces of the polyethylene film were aligned and laminated. Then, three sides were thermally bonded with an impulse sealer to make a bag.

Next, the core material was cut into a size of 300 × 300 mm and inserted into the bag. Next, insert the hose connected to the cylinder of carbon dioxide gas to the back of the bag, and set the carbon dioxide concentration meter (Shin Cosmo Electric Co., Ltd., XP-3140) in the opening of the bag body. Infused. After the carbon dioxide concentration meter reached the desired concentration, the opening of the bag body was thermally bonded with an impulse sealer and sealed. As a result, a heat insulating material having a cross-sectional shape as shown in the conceptual diagram of FIG. .
Table 1 shows the results of evaluation of the used skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 8]
Except for the outer skin material, the same core material and carbon dioxide gas as in Example 2 were used, and a heat insulating material was produced by the same method.

(Skin material)
A polyethylene terephthalate resin (“Mitsui PET J120” manufactured by Mitsui Chemicals, Inc.) was supplied to a single screw extruder, heated to 160 to 280 ° C., and extruded from a T die into a sheet. The extruded sheet is wound around a mirror drum having a temperature of 20 ° C. to be cooled and solidified, and stretched three times in the longitudinal direction using a stretching roll having a preheating temperature of 80 ° C. and a stretching temperature of 100 ° C., and then a preheating temperature of 90 ° C. Using a tenter with a heating temperature of 120 ° C., the film was stretched 3 times in the width direction. Next, heat treatment was performed at a temperature of 180 ° C. for 10 seconds while giving 5% relaxation in the width direction to obtain a resin film. The film was wound by applying a corona discharge treatment at 30 W · min / m ² while maintaining the film temperature at 55 ° C. in an atmosphere of a mixed gas of nitrogen and carbon dioxide (carbon dioxide concentration ratio: 15 vol%). It set in the vacuum evaporation apparatus which equipped the film travel apparatus, and after making it the high pressure reduction state of 1.00 * 10 ^<-2 > Pa, it was made to travel through a 20 degreeC cooling metal drum. At this time, aluminum (“High-Purity Aluminum Wire” manufactured by Nippon Light Metal Co., Ltd.) was heated and evaporated to form a deposited thin film layer on one side. After vapor deposition, the inside of the vacuum vapor deposition apparatus was returned to normal pressure, and the wound film was wound up and aged at a temperature of 40 ° C. for 2 days to obtain a resin film with a vapor deposition layer. The optical density of the metal layer was confirmed in-line during vapor deposition, and the optical density was controlled to be 2.5. The thickness of the obtained resin film with a vapor deposition layer was 120 micrometers. An acrylonitrile-based coating agent was applied as a primer to the resin surface opposite to the metal vapor deposition surface of the obtained resin film, and a 15 μm-thick polypropylene film (“Torphan” (registered trademark) manufactured by Toray Industries, Inc.) was applied to the metal vapor deposition surface. ) BO) was laminated on the resin surface with a polyethylene film having a thickness of 50 μm (“Tretec” (registered trademark) manufactured by Toray Industries, Inc.) to form an outer skin material having a thickness of 185 μm.

  Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 9]
Except for the outer skin material, the same core material and carbon dioxide gas as in Example 2 were used, and a heat insulating material was produced by the same method.

(Skin material)
Using ethylene vinyl alcohol resin (Kuraray “Eval” (registered trademark)), preheated at 50 ° C. and stretched at 70 ° C., stretched three times in the longitudinal direction using a stretching roll, immediately cooled to room temperature and preheated The film was stretched 3 times in the width direction using a tenter at a temperature of 90 ° C. and a stretching temperature of 120 ° C., and then heat-treated at a temperature of 160 ° C. for 10 seconds while giving 5% relaxation in the width direction to obtain a biaxially stretched film. .

The thickness of the obtained resin film was 50 μm. An acrylonitrile-based coating agent was applied as a primer to both sides of the obtained resin film, and a polypropylene film having a thickness of 15 μm (“Trephan” (registered trademark) BO manufactured by Toray Industries, Inc.) was applied to the other side. A polyethylene film having a thickness of 50 μm (“Tretec” (registered trademark) manufactured by Toray Industries, Inc.) was bonded to the surface by dry lamination to obtain a skin material having a thickness of 115 μm.
Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 10]
Except for the core material, the same skin material and carbon dioxide gas as in Example 2 were used, and a heat insulating material was produced by the same method.

(Core material)
A fiber assembly was produced by the following method.

  Polyethylene terephthalate short fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having an average fiber length of 35 mm, a single fiber fineness of 0.8 dtex, and a fiber diameter of 10 μm as the matrix fiber A, and a single fiber fineness of 6.6 as the matrix fiber B Decitex, a polyethylene terephthalate short fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having a fiber diameter of 30 μm was prepared. Further, as a binder fiber, a core-sheath composite fiber (sheath component: low melting point polyethylene terephthalate (sheath component: low-melting polyethylene terephthalate) having an average fiber length of 51 mm, a single fiber fineness of 2.2 dtex, a fiber diameter of 14.2 μm, and a core fiber diameter of 10.0 μm. Melting point 110 ° C.), core component: homopolyethylene terephthalate (melting point 255 ° C.), sheath ratio 50% by weight, Toray Industries, Inc. “Safmet” (registered trademark) T9611).

First, a uniform web was formed by mixing and opening using a card machine so that the mixing ratio of the matrix fiber A, the matrix fiber B, and the binder fiber was 60:20:20. Next, the web was laminated so that the mass per unit area was 0.5 to 5.0 kg / m ^2, and sandwiched between two perforated iron plates with a spacer having a thickness of 50 mm, and a hot air dryer ( The binder fiber was melted by heating at a preset temperature of 170 ° C. for 20 minutes to form a fiber aggregate having a density of 15 kg / m ³ and a thickness of 50 mm.

  Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 11]
Except for the core material, the same skin material and carbon dioxide gas as in Example 2 were used, and a heat insulating material was produced by the same method.

(Core material)
A fiber assembly was produced by the following method.
Polyethylene terephthalate short fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having an average fiber length of 35 mm, a single fiber fineness of 0.8 dtex, and a fiber diameter of 10 μm as the matrix fiber A, and a single fiber fineness of 2.2 as the matrix fiber B Decitex, a polyethylene terephthalate short fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having a fiber diameter of 14 μm was prepared. Further, as a binder fiber, a core-sheath composite fiber (sheath component: low melting point polyethylene terephthalate (sheath component: low-melting polyethylene terephthalate) having an average fiber length of 51 mm, a single fiber fineness of 2.2 dtex, a fiber diameter of 14.2 μm, and a core fiber diameter of 10.0 μm. Melting point 110 ° C.), core component: homopolyethylene terephthalate (melting point 255 ° C.), sheath ratio 50% by weight, Toray Industries, Inc. “Safmet” (registered trademark) T9611).

First, a uniform web was formed by mixing and opening the fibers using a card machine so that the mixing ratio of the matrix fibers A, the matrix fibers B, and the binder fibers was 50:30:20. Next, the web was laminated so that the mass per unit area was 0.5 to 5.0 kg / m ^2, and sandwiched between two perforated iron plates with a spacer having a thickness of 50 mm, and a hot air dryer ( The binder fiber was melted by heating at a preset temperature of 170 ° C. for 20 minutes to form a fiber aggregate having a density of 10 kg / m ³ and a thickness of 50 mm.

  Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 12]
Using the same skin material and core material as in Example 2, a heat insulating material was produced in which the inside was replaced with argon gas.

A heat insulating material having a size of 300 × 300 mm × thickness of 50 mm was produced by the following method.
First, two skin materials were cut into a size of 370 × 370 mm, and the surfaces of the polyethylene film were aligned and laminated. Then, three sides were thermally bonded with an impulse sealer to make a bag.

Next, the core material was cut into a size of 300 × 300 mm and inserted into the bag. Next, insert a hose connected to an argon gas cylinder to the back of the bag, set an oxygen concentration meter (XO-326ALB, manufactured by Shin Cosmo Electric Co., Ltd.) at the opening of the bag, and adjust the oxygen concentration. It was 21% when measured. Subsequently, argon gas was blown in while measuring the oxygen concentration inside the bag. After the oxygen concentration reached 4.2%, the opening of the bag was thermally bonded with an impulse sealer and sealed. (At this time, the argon gas concentration inside the heat insulating material is 80%).
Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Example 13]
Except for the core material, the same outer material and carbon dioxide gas as in Example 1 were used, and a heat insulating material was produced in the same manner.

(Core material)
A fiber assembly was produced by the following method.
The matrix fiber A is an average fiber length of 35 mm, a single fiber fineness of 0.8 decitex, and a polyethylene terephthalate short fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having a fiber diameter of 10 μm. A short polyethylene terephthalate fiber (Toray Co., Ltd. “Tetron” (registered trademark)) having a fiber fineness of 3.3 dtex and a fiber diameter of 19 μm was prepared. Further, as a binder fiber, a core-sheath composite fiber (sheath component: low melting point polyethylene terephthalate (sheath component: low-melting polyethylene terephthalate) having an average fiber length of 51 mm, a single fiber fineness of 2.2 dtex, a fiber diameter of 14.2 μm, and a core fiber diameter of 10.0 μm. Melting point 110 ° C.), core component: homopolyethylene terephthalate (melting point 255 ° C.), sheath ratio 50% by weight, Toray Industries, Inc. “Safmet” (registered trademark) T9611).

First, a uniform web was formed by mixing and opening using a card machine such that the mixing ratio of the matrix fiber A, the matrix fiber B, and the binder fiber was 30:50:20. Next, the web was laminated so that the mass per unit area was 0.5 to 5.0 kg / m ^2, and sandwiched between two perforated iron plates with a spacer having a thickness of 50 mm, and a hot air dryer ( The binder fiber was melted by heating at a preset temperature of 170 ° C. for 20 minutes to form a fiber aggregate having a density of 10 kg / m ³ and a thickness of 50 mm.

  Table 2 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in durability, form retention, and flexibility.

[Examples 14 to 16]
The same skin material and core material as in Example 1 were used, and a heat insulating material having a size of 300 × 300 mm × thickness of 50 mm was produced by the following method.
First, two skin materials were cut into a size of 370 × 370 mm, and the surfaces of the polyethylene film were aligned and laminated. Then, three sides were thermally bonded with an impulse sealer to make a bag.

Next, the core material was cut into a size of 300 × 300 mm and inserted into the bag. Next, insert the hose connected to the krypton gas cylinder to the back of the bag, and set the oxygen concentration meter (Shin Cosmo Electric Co., Ltd., XO-326ALB) in the opening of the bag, It was 21% when measured. Subsequently, krypton gas was blown in while measuring the oxygen concentration inside the bag. After the oxygen concentration reached 2.1%, the opening of the bag was thermally bonded with an impulse sealer and sealed. (At this time, the krypton gas concentration inside the heat insulating material is 90%).
Table 3 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material is excellent in heat insulating performance, durability, shape retention, and flexibility.

[Comparative Example 1]
A heat insulating material was produced by the same method using the same core material and carbon dioxide as in Example 2 except that a polyethylene film was used as the outer skin material.

Table 3 shows the evaluation results of the skin material and the heat insulating material. Although the obtained heat insulating material was excellent in heat insulating performance immediately after creation, it was not durable and a decrease in heat insulating performance occurred.
[Comparative Example 2]
A heat insulating material was produced by the same method except that the same outer skin material and core material as those of Example 2 were used, and the low thermal conductivity gas was not filled (that is, the inside was air).

Table 3 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material was only able to obtain heat insulation performance equivalent to that of general glass wool (thermal conductivity 0.033 to 0.050 W / m · K).
[Comparative Example 3]
Using the same core material as in Example 5 and the same skin material as in Example 8, a vacuum heat insulating material having a size of 300 × 300 mm × thickness of 25 mm was produced by the following method.
First, two skin materials were cut into a size of 370 × 370 mm, and the surfaces of the polyethylene film were aligned and laminated. Then, three sides were thermally bonded with an impulse sealer to make a bag.

Next, the core material was cut into a size of 300 × 300 mm and inserted into the bag. Subsequently, vacuum evacuation was performed using a vacuum drawing device so that the internal pressure was 0.01 Torr, and the opening of the bag was thermally bonded with an impulse sealer and sealed.
Table 3 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material was low in durability and inferior in flexibility.
[Comparative Example 4]
Extruded polystyrene foam "Styro Ace II" (3 types b, A-XPS-B-3b, thickness 50 mm) manufactured by Dow Chemical Co., Ltd. using a core material and a skin material similar to Example 8 A heat insulating material having a size of 300 × 300 mm × thickness of 25 mm was produced by the following method.
First, two skin materials were cut into a size of 370 × 370 mm, and the surfaces of the polyethylene film were aligned and laminated. Then, three sides were thermally bonded with an impulse sealer to make a bag.

Next, the core material was cut into a size of 300 × 300 mm and inserted into the bag. Subsequently, vacuum evacuation was performed using a vacuuming device so that the internal pressure was 0.5 Torr, and the opening of the bag was thermally bonded with an impulse sealer and sealed.
Table 3 shows the evaluation results of the obtained skin material and heat insulating material. The obtained heat insulating material was inferior in flexibility.

According to the present invention, since it has excellent heat insulation performance and can be flexible, it can be easily brought into close contact with the shape of the heat insulation object or filled in the gap. Moreover, since it has sufficient form retentivity, it is possible to provide a heat insulating material with excellent durability that does not undergo deformation or thickness change over a long period of time. The heat insulating material of the present invention is not limited to a heat insulating material for a house (walls, floors, ceilings, foundations, roofs), but is used for a home heater such as a water heater, a fuel cell, a bus unit, a refrigerator, a rice cooker, etc. It can also be applied to industrial electrical appliances, vending machines, refrigerated vehicles, and thermal insulation for transportation.

1: Outer material 2: Core material 3: Heat seal part

Claims (10)

A core material that is a fiber aggregate and has a void inside, and is surrounded by a shell material having a gas barrier property, and is filled with a gas whose thermal conductivity is lower than that of nitrogen. Has a gas barrier property of 15 ml / m ² · day (measuring condition 23 ° C., 0% RH) or less. The fiber assembly includes fibers having a fiber diameter of 15 μm or less with respect to the total weight of the fiber assembly, and a density of 10 kg / m ³ or more and 150 kg / m ³ or less. The heat insulating material according to claim 1. The heat insulating material according to claim 1, wherein the fiber aggregate is a fiber aggregate including matrix fibers and binder fibers. The binder fiber has a core part made of a thermoplastic resin and a sheath part made of a thermoplastic resin having a melting point lower than that of the thermoplastic resin of the core part, and the constituent ratio of the sheath part is based on the total weight of the binder fiber The heat insulating material according to claim 3, wherein the heat insulating material is 40 to 80% by weight. 5. The heat insulating material according to claim 1, wherein the heat insulating material has a bending strength of 20 N / cm ² or less measured according to JIS K7221-2 (2006). The gas having a lower thermal conductivity than nitrogen is at least one gas selected from the group consisting of hydrocarbon, carbon dioxide, argon, krypton, and xenon, and the filling concentration of the gas is 30 to 100%. The heat insulating material according to any one of claims 1 to 5.   The outer skin material is a film having a multilayer structure, and is made of a resin selected from the group consisting of ethylene vinyl alcohol copolymer, polyamide, polyglycolic acid, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and fluorine-based resin. The heat insulating material according to claim 1, comprising at least one gas barrier resin film layer.   Of the multilayer structure of the outer skin material, at least one layer is a reinforcing film layer obtained by blending a resin selected from the group consisting of polyamide, aromatic polyester, aliphatic polyester, and polyolefin resin alone or in combination of two or more. The heat insulating material according to any one of claims 1 to 7.   A film in which at least one of the gas barrier resin film layer and the reinforcing film layer, or a film layer obtained by laminating the gas barrier resin film layer and the reinforcing film layer is uniaxially or biaxially stretched at an area magnification of 2.0 times or more. It is a layer, The heat insulating material in any one of Claims 1-8 characterized by the above-mentioned.   The heat insulating material according to any one of claims 1 to 9, wherein at least one layer of the outer skin material is a vapor deposition layer selected from a metal or a metal oxide.

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