Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/32—Windings characterised by the shape, form or construction of the insulation
  • H02K3/34—Windings characterised by the shape, form or construction of the insulation between conductors or between conductor and core, e.g. slot insulation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
  • H01B3/303—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups H01B3/38 or H01B3/302
  • H01B3/306—Polyimides or polyesterimides
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
  • H01B3/42—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes polyesters; polyethers; polyacetals
  • H01B3/421—Polyesters
  • H01B3/422—Linear saturated polyesters derived from dicarboxylic acids and dihydroxy compounds
  • H01B3/423—Linear aromatic polyesters
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
  • H01B3/18—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances
  • H01B3/30—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes
  • H01B3/47—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of organic substances plastics; resins; waxes fibre-reinforced plastics, e.g. glass-reinforced plastics
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F5/00—Coils
  • H01F5/06—Insulation of windings
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/30—Windings characterised by the insulating material
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/32—Windings characterised by the shape, form or construction of the insulation
  • H02K3/34—Windings characterised by the shape, form or construction of the insulation between conductors or between conductor and core, e.g. slot insulation
  • H02K3/345—Windings characterised by the shape, form or construction of the insulation between conductors or between conductor and core, e.g. slot insulation between conductor and core, e.g. slot insulation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B17/00—Insulators or insulating bodies characterised by their form
  • H01B17/56—Insulating bodies
  • H01B17/62—Insulating-layers or insulating-films on metal bodies

Definitions

• the present invention relates to an insulating material and an insulating sheet used to form the insulating material.
• Insulating materials are used in various places to insulate conductive materials.
• an insulating material is an essential element for insulating the inside of a rotating electric machine.
• Patent Document 1 Japanese Patent Application Laid-open No. 2021-129408
• an annular stator 2 and a rotor 3 located radially inward with respect to the stator 2.
• a plurality of teeth 4a and a plurality of slot portions 8 are mutually formed in the circumferential direction. It is described that a thermoplastic liquid crystal polymer film is used as the insulating material 7 for insulating the slot portion 8.
• Patent Document 2 Japanese Patent Laid-Open No. 2020-120528
• an insulating sheet having a foamed portion and a non-foamed portion insulates the slot portion from the coil, and the foamed portion insulates the coil from the slot portion. It is proposed to be fixed.
• thermoplastic liquid crystal polymer film of Patent Document 1 can prevent the coil from coming into direct contact with the slot portion, it cannot fix the coil.
• the insulating sheet of Patent Document 2 insulation is imparted by the non-foamed portion, and the coil can be fixed to the slot portion by the foamed portion, but there is a risk that the coil may be contaminated due to the foaming. It is also difficult to control the foam to expand anisotropically.
• an object of the present invention is to solve the problems in the prior art, and to provide an insulating material that not only insulates a conductive material but also can fix the conductive material without contaminating it. and an insulating sheet (insulating material precursor) for obtaining an insulating material.
• the present inventors found that by combining a specific expandable layer with an insulating layer, it is possible to expand anisotropically while ensuring insulation properties.
• the insulating material not only has insulating properties but also can efficiently fix the conductive material, thereby completing the present invention.
• An insulating material for insulating a conductive material includes at least one insulating layer and at least one void layer, and fixes the conductive material,
• the at least one void layer is composed of a thermoplastic resin and a plurality of reinforcing fibers, and voids are formed between the plurality of reinforcing fibers,
• the porosity Y [%] of the void layer in the insulating material and the thickness X [ ⁇ m] of the insulating layer in the insulating material are expressed by the following formula (1): 0.01 ⁇ Y/X ⁇ 4.75 (1) Insulating material that meets the requirements.
• the at least one insulating layer is composed of a thermoplastic or thermosetting resin, optionally comprising filler material and/or reinforcing fibers.
• the at least one insulating layer optionally comprises a filler material and/or reinforcing fibers, the group consisting of polyetherimide, polyethylene terephthalate, polyethylene naphthalate and liquid crystal polyester.
• An insulating material for a rotating electric machine which is the insulating material according to any one of aspects 1 to 6, and is used for a rotating electric machine.
• a rotating electrical machine at least in part containing the insulating material for a rotating electrical machine according to aspect 7.
• a stator core having teeth and slots alternately along the circumferential direction;
• a stator for a rotating electric machine comprising: a coil attached to the stator core;
• a rotating electrical machine comprising the insulating material for a rotating electrical machine according to aspect 7 between the inner circumferential surface of the slot and the coil.
• An insulating sheet comprising at least one insulating layer and at least one intumescent layer,
• the at least one expandable layer is composed of a thermoplastic resin and a plurality of reinforcing fibers, the reinforcing fibers have a plurality of intersections, and at least some of the intersections are bonded with the thermoplastic resin,
• the volume content of reinforcing fibers with a degree of curvature of 1.004 or more as defined by the following formula (2) with respect to the volume of the entire reinforcing fibers is 20 vol% or more (preferably may be 30 vol% or more, more preferably 35 vol% or more, more preferably 40 vol% or more).
• Curvature fiber length/shortest distance between both ends of the fiber (2)
• the volume content of reinforcing fibers having a degree of curvature of 1.004 or more is 3 to 50 vol% (preferably 5 to 45 vol%, more preferably 10 to 40 vol%).
• the insulating sheet according to aspect 10 or 11, wherein the reinforcing fibers have an average fiber length of 3 to 100 mm.
• the reinforcing fiber is at least one selected from the group consisting of glass fiber, liquid crystal polyester fiber, aramid fiber, and carbon fiber.
• the resin adhesive to metal is at least one selected from the group consisting of polyetherimide, liquid crystal polyester, polycarbonate, and phenoxy. Insulating sheet.
• the at least one insulating layer is composed of a thermoplastic resin or a thermosetting resin, optionally containing filler material and/or reinforcing fibers. ,Insulating sheet.
• the at least one insulating layer is made of a thermoplastic resin having a melting point or a softening point Ti
• the at least one expandable layer is made of a thermoplastic resin having a melting point or a softening point Ti.
• thermoplastic resin having a softening point Tb, where Ti ⁇ Tb.
• thermoplastic resin constituting the at least one expandable layer is selected from the group consisting of polyetherimide, liquid crystal polyester, polycarbonate, and phenoxy resin. At least one type of insulating sheet.
• at least one insulating layer is made of a thermoplastic resin, and the insulating layer has a thickness of 20 ⁇ m at the interface with the expandable layer.
• An insulating sheet that has the following permeable layers: [Aspect 21] A step of preparing at least one layer each of the insulating sheet according to any one of aspects 10 to 20, or the insulating layer and expandable layer according to any one of aspects 10 to 20; manufacturing an insulating material, comprising the step of heating the thermoplastic resin forming the at least one expandable layer above the melting point or softening point Tb to expand the expandable layer to fix the conductive material and insulate it; Method.
• the expandable layer is composed of reinforcing fibers having a specific curvature, it is possible to expand anisotropically between the conductive materials, and the insulating sheet formed thereby Not only can it fix opposing conductive materials, but it also has excellent insulation properties.
• FIG. 1 is a partially schematic cross-sectional view for explaining an insulating material according to a first embodiment of the present invention.
• 1B is a partially enlarged schematic sectional view of the schematic sectional view of FIG. 1A.
• FIG. 7 is a partially schematic cross-sectional view for explaining an insulating material according to a second embodiment of the present invention.
• FIG. 1 is a partially schematic cross-sectional view for explaining a method of forming an insulating material according to a first embodiment of the present invention
• FIG. 3A is a partially enlarged schematic cross-sectional view of the schematic cross-sectional view of FIG. 3A.
• FIG. FIG. 2 is a conceptual diagram for explaining the degree of curvature of reinforcing fibers.
• FIG. 2 is a schematic cross-sectional view showing a state that the insulating sheet of the present invention can take before expansion. It is a schematic perspective view for demonstrating preparation of the sample for a punching load test.
• FIG. 2 is a schematic cross-sectional view for explaining the production of a sample for a punching load test.
• FIG. 1 is a schematic cross-sectional view for explaining a rotating electric machine described in Patent Document 1.
• FIG. It is an enlarged cross-sectional photograph (magnification: 200 times) of the insulating sheet obtained in Example 11.
• This is an enlarged cross-sectional photograph (200x magnification) of the insulating sheet obtained in Comparative Example 5.
• the insulating material of the present invention is an insulating material for insulating a conductive material, and the insulating material includes at least one insulating layer and at least one void layer, and fixes the conductive material. Further, the present invention also includes a rotating electrical machine that includes at least a portion of an insulating material for a rotating electrical machine.
• the at least one void layer is composed of a thermoplastic resin and a plurality of reinforcing fibers, and voids are formed between the plurality of reinforcing fibers,
• the porosity Y [%] of the void layer in the insulating material and the thickness X [ ⁇ m] of the insulating layer in the insulating material are expressed by the following formula (1): 0.01 ⁇ Y/X ⁇ 4.75 (1) Therefore, it is possible to maintain the desired insulation properties while having a void layer.
• FIG. 1A shows a state in which an insulating material according to a first embodiment of the present invention is disposed in a stator of a rotating electric machine.
• FIG. 1A is a partially schematic sectional view for explaining the first embodiment of the insulating material of the present invention
• FIG. 1B is a partially enlarged schematic sectional view of the schematic sectional view of FIG. 1A.
• the rotating electrical machine 100 includes a stator 2 and an inner rotor 3.
• the stator 2 includes a stator core 4 having teeth 4a and slots 8 alternately along the circumferential direction of the stator, and a stator core 4 having teeth 4a and slots 8 alternately along the stator circumferential direction. It is equipped with a coil 6 which is a conductive material attached thereto.
• the rotating electric machine may include an outer rotor instead of the inner rotor.
• FIG. 1B is a schematic enlarged view showing the insulating layer 13 and the void layer 15 that constitute the insulating material 10.
• the insulating material 10 includes an insulating layer 13 and a void layer 15, the insulating layer 13 is in close contact with the inner peripheral surface of the slot portion 8, and the void layer 15 is in close contact with the coil 6.
• the coil 6 is fixed to the slot portion 8 by an insulating material 10.
• the insulating layer 13 has a thickness of X ⁇ m, and provides insulation to the insulating material.
• the void layer 15 is composed of a thermoplastic resin and a plurality of reinforcing fibers, and voids are formed between the plurality of reinforcing fibers.
• the void layer 15 may have a continuous porous structure.
• the void layer 15 has a communicating hole structure, it can be used for passing a coolant, for example, to cool a motor by passing a coolant through the gaps that exist as communicating holes. is possible.
• the voids in the void layer 15 are formed by the expansion of the expandable layer in the insulating sheet, as described below.
• a plurality of reinforcing fibers curved at a predetermined degree of curvature are fixed with a thermoplastic resin, and by heating the insulating sheet to a temperature higher than the melting point or softening point Tb of the thermoplastic resin, the reinforcing fibers are curved and reinforced. The stress accumulated inside the fibers is released, forming voids between the reinforcing fibers and expanding mainly in the thickness direction to form an insulating material.
• voids are formed between the reinforcing fibers due to expansion of the reinforcing fibers, so there is no risk of contamination of the member due to unexpected foaming compared to when a foamed member is used. Furthermore, since the expandable layer can be expanded anisotropically in the thickness direction, the configuration of the void layer can be easily controlled.
• the coil 6, which cannot be fixed with the insulating sheet before expansion can be fixed with the insulating material 10 having the void layer 15.
• the fixity of the insulating material can be maintained even when a load is applied due to the pressing force or adhesion using the resin.
• FIG. 2 is a partially schematic cross-sectional view for explaining a second embodiment of the insulating material of the present invention.
• the insulating material 20 includes a void layer 25a, an insulating layer 23, and a void layer 25b in this order. That is, the insulating material 20 has a structure in which an insulating layer 23 is inserted between void layers 25a and 25b, and the other parts are the same as those in FIGS. 1A and 1B.
• one void layer 25a of the insulating material 20 is in close contact with the surface of the slot portion 8, and the other void layer 25b is in close contact with the coil 6. As a result, the coil 6 is 20 is fixed to the slot portion 8.
• the conductive material can be fixed in a state where the void layer has a predetermined porosity, while the insulating layer has a predetermined porosity in the void layer from the viewpoint of ensuring the insulation properties of the insulating material. It has a thickness of a predetermined ratio with respect to the thickness.
• the porosity Y [%] of the void layer in the insulation material and the thickness X [ ⁇ m] of the insulation layer in the insulation material are calculated using the following formula (1). 0.01 ⁇ Y/X ⁇ 4.75 (1) is met.
• Y/X may be preferably 0.05 or more, more preferably 0.10 or more, still more preferably 0.20 or more, and even more preferably 0.30 or more. Moreover, Y/X may be preferably 4.00 or less, more preferably 3.00 or less, still more preferably 2.00 or less, and even more preferably 1.60 or less.
• the porosity Y may be appropriately set depending on the relationship with the conductive material to which the insulating material is fixed, and may be, for example, 5 to 95%, preferably 30 to 90%, and more preferably 50 to 80%.
• the insulating material only needs to include at least one void layer, and when the insulating material has a plurality of void layers, the porosity Y of the void layer in the insulating material is calculated as the porosity of all the void layers.
• the insulating material only needs to contain at least one insulating layer, and if the insulating material has multiple insulating layers, the thickness X of the insulating layer in the insulating material is the sum of the thicknesses of all the insulating layers in the insulating material. is used.
• the thickness of the insulating layer of the insulating material is measured by cross-sectional observation in the same manner as the above-mentioned void layer.
• the thickness X of the insulating layer can be selected from a wide range of 10 to 1000 ⁇ m, and may be, for example, 20 to 500 ⁇ m, preferably 30 to 350 ⁇ m, and more preferably 50 to 250 ⁇ m. When the thickness is at least the lower limit, it has excellent insulation properties as an insulating material, and when the thickness is at most the upper limit, it has excellent shapeability and ease of insertion into gaps.
• the insulating material only needs to have at least one insulating layer and at least one void layer, and as shown in FIG. It may be a three-layer structure such as a layer/insulating layer/void layer, an insulating layer/void layer/insulating layer, a four-layer structure such as an insulating layer/void layer/insulating layer/void layer, or a structure of five or more layers. etc.
• the outermost layer may be an insulating layer or a void layer, and can be appropriately set depending on the purpose.
• the material of the insulating layer is not particularly limited as long as it can impart insulation properties to the insulating material, and may be an inorganic material or an organic material, but from the viewpoint of formability, filler materials and It is preferably composed of a thermoplastic resin containing reinforcing fibers and/or a thermosetting resin optionally containing filler material and/or reinforcing fibers. These materials may be used alone or in combination of two or more.
• Polyamide resins such as aliphatic polyamide resins (polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, etc.), semi-aromatic polyamide resins, fully aromatic polyamide resins; polyethylene Polyester resins such as terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; fluorine resins such as polytetrafluoroethylene resins; semiaromatic polyimide resins, polyamideimide resins, polyetherimide resins, etc.
• Thermoplastic polyimide resins polysulfone resins such as polysulfone resins and polyether sulfone resins; modified polyphenylene ether resins; polyethers such as polyether ketone resins, polyether ether ketone resins, and polyether ketone ketone resins.
• Ketone resins polycarbonate resins; amorphous polyarylate resins; liquid crystal polyester resins such as fully aromatic polyester resins; urethane-based, styrene-based, olefin-based, vinyl chloride-based, ester-based, and amide-based thermoplastics Examples include elastomers. These thermoplastic resins may be used alone or in combination of two or more.
• thermoplastic resins having a glass transition temperature of 100° C. or higher include polytetrafluoroethylene resins, thermoplastic polyimide resins, polysulfone resins, semi-aromatic polyamide resins, polyetherketone resins, polycarbonate resins, Examples include liquid crystal polyester resin.
• thermoplastic resins are thermoplastic polyimide resins (preferably polyetherimide resins) and polyetherketone resins (preferably polyetheretherketone resins) from the viewpoint of mechanical properties and moldability.
• the glass transition temperature of the thermoplastic resin may be preferably 105°C or higher, more preferably 110°C or higher. There is no particular restriction on the upper limit, but from the viewpoint of economical use of the insulating sheet, it may be 300° C. or lower. Note that the glass transition temperature is a value measured by the method described in Examples below.
• thermoplastic resin that makes up the insulating layer is stored at the softening point (Tg) of the thermoplastic resin that makes up the void layer.
• the retention rate (E' Tg /E' 25 ⁇ 100), which is expressed as the ratio between the elastic modulus E' Tg and the storage elastic modulus E' 25 at room temperature (25° C.) of the thermoplastic resin constituting the insulating layer, is, for example, , 0.1% or more, or 0.5% or more.
• thermosetting resin used in the present invention examples include phenol resin, urea resin, melamine resin, silicone resin, epoxy resin, and thermosetting polyimide resin.
• thermoplastic polyimide resins preferably polyetherimide resins
• polyethylene terephthalate preferably polyethylene naphthalate
• liquid crystal polyesters preferably liquid crystal polyesters
• the insulating layer may contain filler materials and/or reinforcing fibers, as well as various additives, as necessary.
• filler materials reinforcing fibers, and additives, known or commonly used materials are used.
• thermoplastic resin constituting the void layer is not particularly limited as long as it can soften or melt in the expandable layer and expand due to the repulsion of the reinforcing fibers, as described below, and may vary depending on the material used for the insulating layer. It can be set as appropriate. Furthermore, the thermoplastic resin forming the void layer and the thermoplastic resin forming the insulating layer may be the same or different. For example, when the insulating layer is made of a thermoplastic resin having a melting point or softening point Ti, the thermoplastic resin constituting the void layer is made of a thermoplastic resin having a melting point or softening point Tb. It is preferable that the point Tb satisfies Ti ⁇ Tb.
• the temperature of the thermoplastic resin Tb constituting the void layer may be (Ti-120)°C to Ti°C, preferably (Ti-50), based on the thermoplastic resin Ti constituting the insulating layer. °C ⁇ Ti°C. Note that when the thermoplastic resin has a melting point, the melting point can be used as the reference temperature, and when the thermoplastic resin does not have a melting point, the softening point (glass transition temperature) can be used as the reference temperature.
• thermoplastic resins constituting the void layer include thermoplastic resins used in insulating layers.
• thermoplastic resins constituting the void layer are , polyolefin resin, aliphatic polyamide resin, polyetherimide, liquid crystal polyester, polycarbonate, phenoxy resin, and the like are preferably used.
• a thermoplastic polyimide resin preferably a polyetherimide resin
• the reinforcing fibers constituting the void layer are not particularly limited as long as they can exhibit expandability, and may be organic fibers or inorganic fibers, and may be used alone or in combination of two or more types. It may also be used.
• inorganic fibers include glass fibers, carbon fibers, various ceramic fibers (e.g., silicon carbide fibers, silicon nitride fibers, silica fibers, alumina fibers, zirconia fibers, boron fibers, basalt fibers, etc.), and various metal fibers (e.g., gold, silver, copper, iron, nickel, titanium, stainless steel, etc.).
• the organic fibers are not particularly limited as long as their glass transition temperature or melting point is higher than the softening point of the thermoplastic resin that bonds the intersections of the reinforcing fibers, such as wholly aromatic polyester fibers, polyphenylene sulfide fibers, para-aramid fibers, etc. Examples include fibers, polysulfonamide fibers, phenol resin fibers, polyimide fibers, fluorine fibers, and the like.
• the softening point mainly means the heat deformation temperature in a thermoplastic resin, and may also be, for example, the deflection temperature under load (JIS K 7207). In particular, in the case of an amorphous resin, it means its glass transition temperature.
• insulating fibers for example, glass fibers, liquid crystal polyester fibers, aramid fibers, etc. may be used.
• a method for forming or manufacturing an insulating material includes the steps of preparing an insulating sheet, and heating the thermoplastic resin forming at least one expandable layer in the insulating sheet to a temperature higher than the softening point or melting point of the thermoplastic resin to form the expandable layer.
• the method may include a step of expanding the conductive material, fixing the conductive material, and insulating the conductive material.
• the method for manufacturing an insulating material also includes the steps of preparing at least one insulating layer and at least one expandable layer, and heating to a temperature higher than the softening point or melting point of a thermoplastic resin forming at least one expandable layer in the insulating sheet.
• the method may include a step of expanding the expandable layer to fix the conductive material and insulate the conductive material. Note that the insulating sheet, the insulating layer, and the expandable layer may be used in combination as necessary.
• FIG. 3A is a partially schematic cross-sectional view for explaining an example of a method of forming the insulating material 10 of the first embodiment of the present invention.
• the insulating material 10 is formed by expanding the insulating sheet 30 in the thickness direction of the insulating sheet 30.
• the left side of FIG. 3A shows a state where the insulating sheet 30 is inserted between the inner peripheral surface of the slot portion 8 and the coil 6, and the right side of FIG. 3 shows that the insulating sheet 30 expands due to heating.
• the insulating material 10 is interposed between the inner circumferential surface of the slot portion 6 and the coil 6 to fix the coil 6.
• FIG. 3B is a partially enlarged schematic sectional view of the schematic sectional view of FIG. 3A.
• FIG. 3B is a schematic enlarged view showing the insulating sheet 30 inserted between the inner peripheral surface of the slot portion 6 and the coil 6.
• the insulating sheet 30 has an insulating layer 33 and an expandable layer 35.
• the insulating layer 33 corresponds to the insulating layer 13 of the insulating material 10
• the expandable layer 35 corresponds to the insulating layer 13 of the insulating material 10. This corresponds to the void layer 15 of .
• the reinforcing fibers in a curved state are restrained by the thermoplastic resin, and by heating above the melting point or softening point of the thermoplastic resin constituting the expandable layer 35, the thermoplastic resin As the resin melts or softens, the reinforcing fibers restrained by the thermoplastic resin are released from their curvature, and as a result, a repulsive force (restoring force) of the reinforcing fibers is developed in the thickness direction.
• the insulating sheet 30 irreversibly expands in the thickness direction and fixes the coil 6 in the slot portion 8 as the insulating material 10, as shown in FIG. 1B.
• a thermoplastic resin constituting the insulating material is bonded to the inner circumferential surface of the slot portion 8 and the coil 6 by fusion.
• the insulating material of the present invention can be obtained, for example, by heating the insulating sheet of the present invention to expand the expandable layer as described above.
• the insulating material of the present invention can be prepared by separately preparing an insulating layer and an expandable layer, inserting them separately between conductive materials, and then expanding the expandable layer by heating.
• an insulating material including an insulating layer and a void layer may be formed.
• the insulating material may be fixed in contact with the conductive material and may also insulate the conductive material.
• an insulating sheet e.g., a ribbon-like material
• a conductive material e.g., a conductive material for cables
• the resulting wrapped body is heated, and the expansible layer of the insulating sheet is expanded to form a void layer.
• an insulating material including an insulating layer and a void layer may be formed to insulate the conductive material.
• the insulating material may be in contact with the conductive material for insulation, and the conductive material may be fixed in a predetermined space.
• a predetermined space an insulating sheet is placed adjacent to a conductive material, and an insulating material formed by expanding an expandable layer of the insulating sheet to form a void layer insulates the conductive material in contact with the conductive material.
• an insulating material may fill the predetermined space. The manner in which the conductive material is fixed is determined appropriately depending on the shape of the space, and if the conductive material can be fixed in the space by the expansion of the insulating layer, the space will be completely filled with the insulating material. It doesn't have to be done.
• the electrically conductive material may be fixed by filling the space between the electrically conductive material and at least one wall surface of the space with the insulating material.
• the temperature at which the expandable layer is heated to expand the expandable layer may be Tb or higher, preferably (Tb+10), based on the softening point or melting point Tb of the thermoplastic resin forming at least one expandable layer.
• the temperature may be at least .degree. C., more preferably at least (Tb+20).degree.
• the upper limit of the temperature at which the expandable layer is expanded may be equal to or lower than the thermal decomposition temperature of the thermoplastic resin forming the expandable layer.
• the temperature at which the expandable layer is heated to expand the expandable layer may be set depending on the insulating layer.
• the temperature is such that the insulating layer does not flow.
• the heating temperature may be (Ti + 90) °C or lower, preferably (Ti + 80) °C or lower, more preferably (Ti + 70) °C or lower, based on the softening point or melting point Ti of the thermoplastic resin forming the insulating layer.
• the temperature may be below °C.
• the value of the lowest temperature insulating layer may be used as the reference Ti.
• the insulating sheet of the present invention includes at least one insulating layer and at least one expandable layer.
• the insulating layer corresponds to an insulating layer present in the insulating material.
• the insulating layer of the insulating material is formed of a thermosetting resin or the like, the insulating layer of the insulating sheet may be formed of a precursor before thermosetting.
• the expandable layer is composed of reinforcing fibers and thermoplastic resin.
• the expandable layer may contain substances other than reinforcing fibers and thermoplastic resin as long as the effects of the present invention are not impaired.
• the reinforcing fibers have a plurality of intersections, and at least some of the intersections are bonded with thermoplastic resin.
• the reinforcing fibers may be randomly oriented and have a plurality of intersection points, and at least some of the intersection points of the reinforcing fibers may be bonded with a thermoplastic resin.
• the intersection points of the reinforcing fibers are centered.
• the thermoplastic resin may be present in the form of a web, or the reinforcing fibers may be embedded in the thermoplastic resin forming the matrix.
• the volume content of reinforcing fibers having a degree of curvature defined by the following formula (2) of 1.004 or more may be 20 vol % or more with respect to the volume of the entire reinforcing fibers.
• Curvature fiber length/shortest distance between both ends of the fiber (2)
• FIG. 5 is a conceptual diagram for explaining the degree of curvature of reinforcing fibers.
• the reinforcing fibers in the expandable layer have an arched shape centered approximately at the center.
• the fiber length in the above formula (2) indicates the length L along the curved shape of the fiber, and the shortest distance between both ends of the fiber indicates the distance L 0 of a straight line connecting two points at both ends of the fiber.
• the curved reinforcing fibers are not limited to the arched shape as shown in FIG. 5, but may have a chevron shape or a wave shape.
• Residual stress occurs due to the reinforcing fibers being curved, and when the insulating sheet is heated, the thermoplastic resin that makes up the expandable layer flows, and reinforcing fibers with a degree of curvature of 1.004 or more have a large repulsive force. Even when combined with an insulating layer for ensuring the insulation properties of the insulating material, it is possible to ensure the fixation of the fixing material due to the repulsive force.
• the volume content of reinforcing fibers with a degree of curvature of 1.004 or more with respect to the volume of the entire reinforcing fibers may be preferably 30 vol% or more, more preferably 35 vol% or more, and even more preferably 40 vol%. % or more.
• the upper limit of the volume content of reinforcing fibers having a degree of curvature of 1.004 or more with respect to the volume of the entire reinforcing fibers is not particularly limited, but may be, for example, 100%. Note that the degree of curvature of the reinforcing fibers is a value measured by the method described in Examples below.
• the repulsive force of the curved reinforcing fibers will be expressed in the thickness direction, so such an expandable layer will increase in thickness when heated. It expands in the longitudinal direction, and expansion stress occurs in the thickness direction.
• the volume content of reinforcing fibers with a degree of curvature of 1.004 or more may be 3 to 50 vol% with respect to the volume of the entire expandable layer, and is preferably may be 5 to 45 vol%, more preferably 10 to 40 vol%.
• the volume content of reinforcing fibers with a degree of curvature of 1.004 or more with respect to the volume of the entire expandable layer is the ratio of the volume occupied by reinforcing fibers with a degree of curvature of 1.004 or more with respect to the bulk volume of the expandable layer. This is a value measured by the method described in the Examples below.
• the average degree of curvature of the reinforcing fibers may be 1.003 or more, preferably 1.004 or more, more preferably 1.005 or more, and even more preferably may be 1.006 or more.
• the upper limit of the average degree of curvature of the reinforcing fibers may be, for example, 1.05 or less, preferably 1.04 or less, and more preferably 1.03 or less. Note that the average degree of curvature of the reinforcing fibers is a value measured by the method described in Examples below.
• the weight content of the reinforcing fibers is 15 to 60 wt% based on the total weight of the expandable layer.
• the content is preferably from 18 to 55 wt%, even more preferably from 20 to 50 wt%, and even more preferably from 25 to 48 wt%. If the weight content of the reinforcing fibers is too low, the reinforcing fibers will be less likely to come into contact with each other, making it difficult for the reinforcing fibers to curve.
• the reinforcing fibers cannot be maintained in a curved state due to the small amount of thermoplastic resin, and it tends to be difficult to adjust the degree of curvature of the reinforcing fibers.
• the expansible layer preferably has a thermoplastic resin weight content of 40 to 85 wt% based on the total weight of the expansible layer.
• the percentage may be more preferably 45 to 82 wt%, even more preferably 50 to 80 wt%, even more preferably 52 to 75 wt%. If the amount of thermoplastic resin is small, the contribution of the molten thermoplastic resin to adhesion will be small, so there is a risk that reinforcing force or fixing force will be insufficient.
• the thermoplastic resin contained in the expandable layer may contain a binder component used as necessary for manufacturing a nonwoven fabric as a composite sheet.
• the expandable layer increases the area of the thermoplastic resin in contact with the conductive material, and from the viewpoint of ensuring sufficient expandability, the volume ratio of reinforcing fibers and thermoplastic resin (reinforcing fibers: thermoplastic resin) is adjusted. However, it may be from 10:90 to 70:30.
• the volume ratio of reinforcing fibers to thermoplastic resin (reinforcing fibers: thermoplastic resin) may be preferably 15:85 to 65:35, more preferably 20:80 to 60:40.
• the average basis weight of the expandable layer can be varied depending on the space to be filled and the purpose.For example, it can be selected from a wide range of 10 to 10,000 g/ m2 , but it can be selected with high precision even in narrow spaces. From the viewpoint of being able to be filled, the amount may be 10 to 500 g/m 2 , preferably 20 to 400 g/m 2 , and more preferably 50 to 300 g/m 2 .
• the average basis weight of the expandable layer is a value measured by the method described in Examples below.
• the density of the expandable layer can be varied depending on the space to be filled and the purpose, but it may be 0.5 to 5 g/cm, preferably 0.6 to 4 g/cm. 3 , more preferably 0.7 to 3 g/cm 3 . Note that the density of the expandable layer is a value measured by the method described in Examples below.
• the expandable layer may have a release rate of curvature defined by the following formula (3) of 20% or more, preferably 30% or more, more preferably 40% or more, still more preferably 50% or more, and More preferably, it may be 60% or more.
• the release rate of the degree of curvature is an index that indicates how much ability the expandable layer has to thermally expand, and the expandable layer having the release rate of the degree of curvature as described above can be filled in a predetermined space. Excellent strength for reinforcing spaces and fixing materials.
• the upper limit of the release rate of the degree of curvature is not particularly limited, but may be, for example, 100%.
• Curvature release rate (%) [(A-1)-(B-1)]/(A-1) ⁇ 100 (3) (In the formula, A: average degree of curvature of the reinforcing fibers in the expandable layer before expansion, B: average degree of curvature of the reinforcing fibers in the expandable layer after being heated and expanded under no pressure.)
• the expandable layer does not substantially contain volatile substances that evaporate during heating (e.g., low-molecular compounds with a boiling point lower than the heating temperature), blowing agents, expanded graphite, etc.
• the total amount of volatile materials in the intumescent layer may be less than 0.5 wt%.
• the temperature is (Tb+10)°C or higher based on the melting point or softening point (Tb) of the thermoplastic resin of the expandable layer.
• the temperature may be preferably (Tb+30)°C or higher, more preferably (Tb+50)°C or higher.
• the upper limit of the heating temperature may be, for example, (Tb + 250) °C or less, preferably (Tb + 200) °C or less, and from the viewpoint of suppressing deterioration of the thermoplastic resin, it is more preferably (Tb + 150) °C or less. .
• the insulating sheet may expand rapidly, or may expand slowly to have an overall uniform structure.
• the heating time for expansion may be 1.
• the time may be about minutes to 1 hour, preferably about 10 to 50 minutes.
• Such an expandable layer is formed from an expandable layer precursor.
• the expandable layer includes a step of preparing an expandable layer precursor containing reinforcing fibers and a thermoplastic resin, and heating the expandable layer precursor to a temperature higher than the melting point or softening point of the thermoplastic resin.
• the thermoplastic resin may include at least the steps of hot pressing by applying pressure in the thickness direction, and cooling to a temperature lower than the melting point or softening point of the thermoplastic resin while the pressure is being applied.
• the degree of curvature of the reinforcing fibers by adjusting the ratio of reinforcing fibers in the expandable layer precursor, the number of expandable layer precursors subjected to heat pressing, the hot pressing conditions, etc.
• the expandable layer precursor is a material that includes reinforcing fibers and a thermoplastic resin and can form an expandable layer through a hot pressing process and a cooling process, and various forms of sheet-like materials can be used.
• the expandable layer precursor include a nonwoven fabric of a mixture of reinforcing fibers and thermoplastic fibers, or a nonwoven fabric of reinforcing fibers in which particulate (or granular) thermoplastic resin is dispersed. It may also be a nonwoven fabric mixed with thermoplastic fibers.
• a wet nonwoven fabric containing reinforcing fibers and thermoplastic fibers e.g., mixed paper, hereinafter referred to as "mixed paper” in the present invention, a mixed nonwoven fabric produced by a wet papermaking method is referred to as a mixed paper).
• mixed paper a mixed nonwoven fabric produced by a wet papermaking method
• a mixed paper is more preferable.
• the types of reinforcing fibers and thermoplastic resin are the same as the types of reinforcing fibers and thermoplastic resin used in insulating materials, so their description is omitted here.
• the reinforcing fibers used may be continuous fibers, but are preferably discontinuous fibers, and the average fiber length is preferably 3 to 100 mm from the viewpoint of increasing the repulsion force of the reinforcing fibers.
• the length may be more preferably 4 to 80 mm, and even more preferably 5 to 50 mm. Note that the average fiber length is a value measured by the method described in Examples below.
• the average fiber diameter of the single fibers is 2 to 40 ⁇ m.
• the thickness may be more preferably 3 to 30 ⁇ m, and even more preferably 4 to 20 ⁇ m. Note that the average fiber diameter is a value measured by the method described in Examples below.
• the aspect ratio of the single fibers is 100 to 50,000. It may be more preferably 300 to 10,000, and even more preferably 500 to 5,000.
• the reinforcing fibers preferably have a tensile modulus of 10 GPa or more from the viewpoint of increasing the repulsive force of the reinforcing fibers. It may be more preferably 30 GPa or more, and still more preferably 50 GPa or more. There is no particular restriction on the upper limit, but it may be 1000 GPa or less.
• the tensile modulus should be measured by a method that complies with the standards suitable for each fiber, such as JIS R 7606 for carbon fibers, JIS R 3420 for glass fibers, and JIS L 1013 for organic fibers. I can do it.
• the weight content of the reinforcing fibers may be 15 to 60 wt%, preferably 18 to 55 wt%, based on the total weight of the expandable layer precursor. %, more preferably 20 to 50 wt%, still more preferably 25 to 48 wt%. If the content of the reinforcing fibers is too low, the reinforcing fibers will be less likely to come into contact with each other, making it difficult for the reinforcing fibers to curve.
• the content of reinforcing fibers is too high, the reinforcing fibers cannot be maintained in a curved state due to the small amount of thermoplastic resin, and it tends to be difficult to adjust the degree of curvature of the reinforcing fibers.
• thermoplastic fibers obtained by fiberizing the above-mentioned thermoplastic resin by a known method can be used.
• the mixed nonwoven fabric used in the present invention may have a thermoplastic fiber weight content of 40 to 85 wt% based on the total weight of the mixed nonwoven fabric, from the viewpoint of adjusting the degree of curvature of the reinforcing fibers in the resulting expandable layer. , preferably 45 to 82 wt%, more preferably 50 to 80 wt%, even more preferably 52 to 75 wt%.
• the single fiber fineness of the thermoplastic fiber is preferably 0.1 to 20 dtex from the viewpoint of improving the dispersibility of reinforcing fibers. In order to obtain an expandable layer with excellent expansion stress upon heating, it is desirable to uniformly disperse the reinforcing fibers in the mixed nonwoven fabric.
• the single fiber fineness of the thermoplastic fiber may be more preferably 0.5 to 18 dtex, and even more preferably 1 to 16 dtex. Note that the single fiber fineness is a value measured by the method described in Examples below.
• the average fiber length of the thermoplastic fibers is preferably 0.5 to 60 mm, more preferably 1 to 55 mm, and even more preferably 3 to 50 mm, from the viewpoint of improving the dispersibility of reinforcing fibers. .
• the average fiber length is a value measured by the method described in Examples below.
• the cross-sectional shape of the fibers there is no particular restriction on the cross-sectional shape of the fibers, and the cross-sectional shape of the fibers may be circular, hollow, flat, or irregularly shaped such as a star shape.
• the mixed nonwoven fabric may contain a binder component as necessary.
• the weight content of the binder component with respect to the mixed nonwoven fabric may be, for example, 10 wt% or less.
• the shape of the binder component may be fibrous, particulate, liquid, etc., but from the viewpoint of forming a nonwoven fabric, binder fibers are preferred.
• the binder component is not particularly limited and includes, for example, polyolefin resins, polyamide resins, polyester resins, acrylic resins, polyvinyl alcohol resins, polyurethane resins, and polyester resins are preferred.
• binder components correspond to components constituting the thermoplastic resin of the resulting expandable layer. From the viewpoint that the binder component becomes a part of the matrix as a thermoplastic resin, it is preferable to use a binder component that is compatible with the thermoplastic fibers. Because of this, it has excellent strength.
• a polyester resin By using such a polyester resin, the strength of the mixed nonwoven fabric can be improved due to good binder properties, so that it is excellent in process passability and thermal decomposition during high temperature molding can be suppressed.
• the polyester resin may contain a small amount (for example, 5 mol % or less) of a dicarboxylic acid component other than terephthalic acid and isophthalic acid, either alone or in combination, as long as the effects of the present invention are not impaired.
• a dicarboxylic acid component other than terephthalic acid and isophthalic acid either alone or in combination, as long as the effects of the present invention are not impaired.
• ethylene glycol can be used as a diol component, but a small amount (for example, 5 mol% or less) of other diol components other than ethylene glycol may be used in combination of one or more types. may also be included.
• the method for producing the nonwoven fabric there are no particular limitations on the method for producing the nonwoven fabric, and examples include spunlace method, needle punch method, steam jet method, dry papermaking method, wet papermaking method (wet laid process), and the like.
• the wet papermaking method is preferred in terms of production efficiency and uniform dispersion of reinforcing fibers in the nonwoven fabric.
• an aqueous slurry containing thermoplastic fibers and reinforcing fibers may be prepared, and then this slurry may be subjected to a normal papermaking process.
• the aqueous slurry may contain the above-mentioned binder fibers (for example, water-soluble polymer fibers such as polyvinyl alcohol fibers, heat-fusible fibers such as polyester fibers), etc., as necessary.
• a binder component may be applied by spray drying, or a hot press process may be added after the wet papermaking process.
• an aqueous slurry further containing a dispersant may be used from the viewpoint of increasing the uniformity of the thickness and basis weight of the expandable layer obtained.
• a dispersant known dispersants capable of dispersing reinforcing fibers and thermoplastic fibers in water can be used, such as polyalkylene oxide-based dispersants, polyacrylamide-based dispersants, and polyacrylic acid-based dispersants. Examples include polymeric dispersants such as dispersants and urethane resin dispersants.
• an aqueous slurry further containing a thickener may be used.
• the thickener include anionic polyacrylamide and nonionic polyethylene oxide.
• anionic polyacrylamide it is preferable to use anionic polyacrylamide as the thickener. This is because it becomes easier to obtain a mixed bundle of fibers when the cationic compound is added.
• the basis weight of the nonwoven fabric is not particularly limited, it is preferably 5 to 1500 g/m 2 . It may be more preferably 10 to 1000 g/m 2 , and even more preferably 20 to 500 g/m 2 .
• the expandable layer precursor may be heated to a temperature higher than the melting point or softening point of the thermoplastic resin, and then hot pressed by applying pressure in the thickness direction.
• the reinforcing fibers are compressed in a state in which they are in contact with each other, so that the reinforcing fibers can be curved.
• the reinforcing fibers are adjusted by adjusting the heat pressing conditions described below depending on the content ratio of reinforcing fibers and thermoplastic resin in the expandable layer precursor and the basis weight and number of sheets of the expandable layer precursor. It is possible to adjust the degree of curvature.
• the molding temperature at that time may be set in accordance with the softening point and melting point of the thermoplastic resin of the expandable layer precursor to be used.
• the heating temperature is preferably higher than the melting point or softening point of the thermoplastic resin of the expandable layer precursor.
• the heating temperature is higher than the melting point of the thermoplastic resin, (melting point + 100°C)
• the following ranges are preferable.
• the heating temperature is preferably in the range of not less than the glass transition temperature of the thermoplastic resin and not more than (glass transition temperature + 200)°C as a softening point. Note that, if necessary, preliminary heating may be performed using an IR heater or the like before hot pressing.
• the pressure during hot pressing is usually carried out at a pressure of 0.05 MPa or higher.
• the pressure may be more preferably 0.1 MPa or more, and even more preferably 0.5 MPa or more.
• the upper limit is not particularly limited, but may be about 30 MPa.
• the time for heat pressing but if exposed to high temperatures for a long time, the thermoplastic resin may deteriorate, so it is usually preferably within 30 minutes, and more preferably within 25 minutes. , more preferably within 20 minutes.
• the lower limit is not particularly limited, it may be about 1 minute.
• one or more sheets of the above-mentioned expandable layer precursor can be laminated and hot-pressed.
• preferable conditions vary, from the viewpoint of adjusting the degree of curvature of the reinforcing fibers, a multilayer body obtained by laminating a plurality of the above expandable layer precursors (for example, 2 to 100 sheets, preferably 3 to 50 sheets) is hot-pressed. You may.
• the type of reinforcing fibers and the pressure to be applied can be set as appropriate. Furthermore, there is no particular restriction on the shape of the expandable layer obtained, and it can be set as appropriate. Depending on the purpose, it is also possible to laminate multiple layers of mixed nonwoven fabrics with different specifications, or to place mixed nonwoven fabrics with different specifications separately in a mold of a certain size and heat press them. .
• an expandable layer having a predetermined shape can be obtained by cooling to a temperature lower than the melting point or softening point of the thermoplastic resin while keeping the pressure applied in the hot pressing step.
• the state of the reinforcing fibers adjusted to a specific degree of curvature in the heat press process as described above can be maintained, and a specific amount of reinforcing fibers with a specific degree of curvature are present.
• An intumescent layer can be obtained.
• pressure may be applied to the expandable layer precursor using a press device equipped with a pressure dispersion mechanism.
• the insulating sheet may be manufactured by separately manufacturing the insulating layer and the expandable layer, and then integrating them by fusing or using an adhesive.
• an insulating sheet may be manufactured by overlapping an insulating layer and an expandable layer precursor and integrating the insulating layer with the insulating layer in the process of forming the expandable layer as described below.
• the insulating sheet when the insulating layer is made of thermoplastic resin, the insulating sheet may be manufactured by fusing and integrating the insulating layer and the expandable layer in a hot pressing process.
• the heating temperature in the hot pressing step is preferably such that the thermoplastic resin forming the insulating layer does not flow excessively in the hot pressing step.
• the thermoplastic resin forming the insulating layer is an amorphous resin
• the heating temperature may be (Ti + 50) °C or lower, preferably (Ti + 40) °C or lower, more preferably (Ti + 40) °C or lower, based on the softening point Ti. may be (Ti+30)°C or less.
• the temperature may be less than Ti°C, preferably (Ti-20)°C or less, more preferably (Ti-40), based on the melting point Ti. °C or less, and the lower limit value may be (Ti-60) °C or more.
• the value of the lowest temperature insulating layer may be used as the reference Ti.
• An insulating sheet whose insulating layer is made of thermoplastic resin is based on the theory of the expandable layer calculated from the thickness of the insulating layer and the expandable precursor when the expandable layer and the insulating layer are integrated by fusion. It is preferable to set the conditions of the hot pressing process so that the thickness of the insulating sheet becomes larger when compared to the sum of the thicknesses.
• the insulating layer when the insulating layer is made of thermoplastic resin, the insulating layer may have a permeable layer at the interface with the expandable layer.
• the permeable layer is a layer formed when some of the reinforcing fibers used in the expandable layer penetrate into the insulating layer, and during the heat pressing process when forming the insulating sheet, the thermoplastic resin in the insulating layer It is formed by flowing.
• the thickness of the permeable layer can be determined by the distance from the interface between the insulating layer and the expandable layer to the point in the insulating layer where the reinforcing fibers have penetrated the most.
• FIGS. 8 and 9 show enlarged cross-sectional photographs of the insulating layers obtained in Example 11 and Comparative Example 5, respectively.
• the thickness of the permeable layer can be determined by the distance from the resin interface between the insulating layer and the expandable layer to the upper end of the fiber that penetrates the deepest into the insulating layer.
• the resin interface between the insulating layer and the expandable layer may be determined from the appearance of the resin, or if the resin interface cannot be clearly determined from the appearance, the resin interface between the insulating layer and the expandable layer may be determined by the group of reinforcing fibers present in the expandable layer.
• the upper end portion of the fibers present at the upper end may be determined as the resin interface between the insulating layer and the expandable layer.
• the thickness of the permeable layer the sum of the thicknesses of the permeable layers in the insulating sheet is used.
• the thickness of the permeation layer may be, for example, 20 ⁇ m or less, preferably 0.5 to 18 ⁇ m.
• the presence of the permeable layer can improve the adhesion between the insulating layer, the expandable layer, and the void layer, and can improve the integrity of the insulating sheet and the insulating material.
• the insulating sheet can be easily folded and bent, it can be deformed as appropriate depending on the space into which it is inserted.For example, when disposed in the slot portion of the stator core, it It may have various cross-sectional shapes.
• the average thickness of the insulating sheet can be varied depending on the space to be filled and the purpose.For example, it can be selected from a wide range of 0.01 to 20 mm. From the viewpoint of being able to fill gaps with high accuracy, the thickness may be 10 to 1000 ⁇ m, preferably 20 to 500 ⁇ m, and more preferably 50 to 300 ⁇ m. Note that the average thickness of the insulating sheet is a value measured by the method described in Examples below.
• the basis weight of the insulating sheet can be varied depending on the space to be filled and the purpose.For example, it can be selected from a wide range of 10 to 1000g/ m2 , but it is difficult to insert it into a narrow gap with precision. From the viewpoint of being able to fill gaps well, the amount may be 10 to 800 g/m 2 , preferably 40 to 600 g/m 2 , and more preferably 50 to 500 g/m 2 . Note that the basis weight of the insulating sheet is a value measured by the method described in Examples below.
• the density of the insulating sheet can be varied depending on the space to be filled and the purpose. For example, it can be selected from a wide range of 0.10 to 3.00 g/ cm3 , but it is From the viewpoint of being able to insert and fill the gap with high accuracy, it may be 0.50 to 1.80 g/cm 3 , preferably 0.65 to 1.70 g/cm 3 , more preferably 0.85 to 1.80 g/cm 3 . It may be 1.60 g/cm 3 . Note that the density of the insulating sheet is a value measured by the method described in Examples below.
• the expansion rate in the thickness direction of the insulating sheet may be 101 to 400%, preferably 120 to 400%. , more preferably 130 to 300%, still more preferably 140 to 250%.
• the expansion coefficient in the thickness direction is measured under no load, and an expansion test is performed in which the insulation sheet is heated until there is no change in thickness.
• the insulating sheet can expand anisotropically in the thickness direction, and the dimensional change rate due to expansion or contraction in the direction perpendicular to the thickness direction is -10 before and after the expansion test described above. It is preferably 10%.
• the dimensional change rate in the direction perpendicular to the thickness direction indicates contraction when negative, and expansion when positive.
• the dimensional change rate in the direction perpendicular to the thickness direction may be more preferably -8 to 8%, and still more preferably -5 to 5%.
• the reinforcing fibers of the insulating sheet are oriented in the plane direction, and in the case of such a structure, it is possible to reduce the rate of dimensional change due to expansion or contraction in the direction perpendicular to the thickness direction. can.
• the dimensional change rate due to expansion or contraction in the direction orthogonal to the thickness direction of the insulating sheet is a value measured by the method described in Examples below.
• the insulation sheet may have a dielectric breakdown voltage of 40 kV/mm or more after the above-mentioned expansion test, preferably 45 kV/mm or more, more preferably 50 kV/mm or more. good.
• the insulating sheet When the target electrically conductive material is metal, the insulating sheet preferably has excellent adhesion to the metal.
• the adhesion between the resin and metal that make up the insulating sheet can be judged by the difficulty of peeling off the laminated state of the resin and metal, and generally speaking, if they are not adhered, the two will be separated. Since separation occurs at the interface, the adhesion strength of the insulating sheet (or insulating material) to the metal can be determined by a known or commonly used method. Further, it may be grasped as a push-out load using a jig to be described later.
• the push-out load may be 5N or more, preferably 10N or more, more preferably 15N or more, and still more preferably 20N or more. There may be.
• the upper limit of the punching load is not particularly limited, it may be, for example, about 100N. Note that the punching load is a value measured by the method described in Examples below.
• the insulating sheet of the present invention can efficiently produce the insulating material of the present invention, and the insulating material of the present invention can be used not only for the above-mentioned rotating electric machines, but also for various types of insulating and fixing conductive materials. It can be used in a wide range of applications. Such uses include, for example, cable covering materials, electrical wiring covering materials, etc.
• the insulating material of the present invention can both fix and insulate a plurality of cables or wiring.
• Average fiber length The fiber length of 100 randomly selected fibers was measured, and the average value of the measured values was taken as the average fiber length.
• Average fiber diameter The fiber diameters of 30 randomly selected fibers were measured by microscopic observation, and the average value of the measured values was taken as the average fiber diameter.
• the glass transition temperature of the sample was determined by measuring the temperature dependence of the loss tangent (tan ⁇ ) using a solid state dynamic viscoelasticity device "Rheospectra DVE-V4" manufactured by Rheology, at a frequency of 10 Hz and a heating rate of 10 ° C/min. It was determined from the peak temperature.
• the peak temperature of tan ⁇ is the temperature at which the first differential value of the amount of change in the value of tan ⁇ with respect to temperature becomes zero.
• the peak temperature existing on the higher temperature side was defined as the glass transition temperature of the thermoplastic resin.
• melting point of thermoplastic resin The melting point of the sample was measured using Mettler's "TA3000-DSC" by raising the temperature to 350°C at a heating rate of 10°C/min in a nitrogen atmosphere, and the peak temperature of the observed melting peak was determined as the melting point. (°C).
• the content rate of the thermoplastic resin was calculated as the value obtained by dividing the content rate of all reinforcing fibers, setting the total ratio as 100%.
• the thickness of the insulating layer is determined by the amount of reinforcing fiber that penetrates into the insulating layer by being integrated with the insulating layer by heat pressing.
• the distance was determined as the distance from the interface between the insulating layer and the expandable layer to the point in the insulating layer where the reinforcing fibers had penetrated the most.
• the density (g/cm 3 ) of the expandable layer was calculated as the basis weight (g/m 2 )/thickness ( ⁇ m) of the expandable layer.
• Image analysis conditions > Image analysis software: Avizo (manufactured by Thermo Fisher Scientific) After cutting the three-dimensional image of the insulating sheet sample obtained by X-ray CT measurement to 0.40 mm x 0.40 mm x total thickness using image analysis software, use a NON-LOCAL Filter as necessary. The function removed noise. The NON-LOCAL Filter function was set under the following conditions. Spatial Standard Deviation value: 5 Intensity Standard Deviation value: 0.2 Search window value: 10 Local neighborhood value: 3 Then, binarization was performed using the Interactive Thresholding function to extract all fibers.
• the "Tortuosity" of each extracted fiber was defined as the degree of curvature.
• the volume content (vol%) of reinforcing fibers having a degree of curvature of 1.004 or more with respect to the volume occupied by all the extracted reinforcing fibers was calculated. This was defined as the "proportion of fibers with a degree of curvature of 1.004 or more in the reinforcing fibers" in Tables 1 and 3.
• the volume occupied by all reinforcing fibers in the volume content of all reinforcing fibers with respect to the volume of the entire expandable layer in an insulating sheet which is calculated with reference to JIS K 7075 "Fiber content and void ratio test of carbon fiber reinforced plastics"
• the volume content (vol%) of reinforcing fibers with a curvature of 1.004 or more with respect to the volume of the entire insulating sheet was calculated by multiplying the volume content of reinforcing fibers with a curvature of 1.004 or more with respect to the volume of the entire insulating sheet.
• volume content of reinforcing fibers with a curvature of 1.004 or more with respect to the volume of the entire expansible layer in the insulating sheet that is, the volume content of reinforcing fibers with a curvature of 1.004 or more in the inflatable layer in Tables 1 and 3. percentage.
• Average degree of curvature total degree of curvature of each extracted fiber / number of extracted fibers
• FIG. 6A is a schematic perspective view for explaining the production of a sample for the punching load test
• FIG. 6B is a schematic cross-sectional view for explaining the production of the sample for the punching load test.
• the insulating sheets obtained in Examples and Comparative Examples were cut out to a length of 50 mm and a width of 15 mm to prepare insulating sheet samples.
• a hollow square timber (large) 42a with a length of 20 mm, a width of 20 mm, a thickness of 2.15 mm, and a length of 100 mm was prepared, and a hollow square timber (small) 42b with a width of 15 mm, a thickness of 1.5 mm, and a length of 100 mm were prepared.
• the hollow square timber (small) 42b is inserted into the hollow square timber (large) 42a, the inside lateral surface of the hollow square timber (large) 42a and the outside lateral surface of the hollow square timber (small) 42b.
• Hollow square timbers (small) having vertical dimensions such that the gap had a predetermined height were prepared in each of the Examples and Comparative Examples.
• the vertical dimension of the hollow square material (small) 42b was adjusted to be (inner vertical dimension (15.7 mm) of the hollow square material (large) 42a - gap height h x 2).
• the hollow square timber (large) 42a is inserted into the hollow square timber (large) 42a.
• One insulating sheet sample 30 was inserted into each of the two gaps between the inner side surface and the outer side surface of the hollow square timber (small) 42b, and a constant temperature incubator (manufactured by Yamato Scientific Co., Ltd.) set at 280°C was used. DN411H”) and heated for 20 minutes, then taken out and cooled to 25° C., thereby expanding and fixing the expandable layer in the insulating sheet.
• the thicknesses of the insulating layer and the void layer are each measured by cross-sectional observation.
• the bulk density (g/cm 3 ) of the void layer is calculated by dividing the basis weight (g/m 2 ) of the void layer by the thickness ( ⁇ m) of the void layer.
• the porosity was calculated from the following formula.
• Porosity (%) (1-bulk density of void layer/true density of void layer) x 100
• the thicknesses of the insulating layer and the void layer are each measured by cross-sectional observation.
• the bulk density (g/cm 3 ) of the void layer is calculated by dividing the basis weight (g/m 2 ) of the void layer by the thickness ( ⁇ m) of the void layer.
• the porosity was calculated from the following formula.
• Porosity (%) (1-bulk density of void layer/true density of void layer) x 100 Further, in calculating the true density of the void layer, the specific gravity measured using a hydrometer for the void layer separated from the insulating layer of the insulating material may be used as the true density.
• Dielectric breakdown voltage Referring to JIS C 2110 "Solid Electrical Insulating Materials - Test Method for Dielectric Breakdown Strength", the dielectric breakdown voltage (kV) of the sample expanded without load was measured. Further, the value was divided by the thickness of the sample to calculate the dielectric breakdown voltage (kV/mm) per thickness.
• PEI polyetherimide
• ULTEM9001 manufactured by Cervic Innovative Plastics
• the PEI-based polymer was discharged from a round hole nozzle under the conditions of a spinning head temperature of 390° C., a spinning speed of 1500 m/min, and a discharge rate of 50 g/min to produce a multifilament of PEI fibers of 2640 dtex/1200 f.
• the obtained multifilament was cut into 15 mm pieces to produce short-cut PEI fibers.
• the appearance of the obtained fibers was good with no fluff, the single fiber fineness was 2.2 dtex, the average fiber length was 15.0 mm, and the glass transition temperature (softening point of an amorphous thermoplastic resin) was 217 ° C. , the density was 1.27 g/ cm3 .
• the obtained PET-based polymer was supplied to a co-rotating type vented twin-screw extruder heated at 270°C, and after a residence time of 2 minutes, it was introduced to a spinning head heated to 280°C, and the output amount was 45 g/
• a multifilament made of PET-based polymer with a diameter of 2640 dtex/1200 f was produced by discharging it from a round hole nozzle under conditions of 1200 m/min and taking it off at a spinning speed of 1200 m/min. The obtained fiber was then cut into 5 mm pieces. The appearance of the obtained fibers was good with no fuzz, single fiber fineness was 2.2 dtex, average fiber length was 5 mm, and density was 1.38 g/cm 3 .
• PC polycarbonate
• Iupilon S-3000 manufactured by Mitsubishi Engineering Plastics
• the PC-based polymer was discharged from a round hole nozzle under the conditions of a spinning head temperature of 300° C., a spinning speed of 1500 m/min, and a discharge rate of 50 g/min to produce a multifilament of PC fibers of 2640 dtex/1200 f.
• the obtained multifilament was cut into 15 mm pieces to produce short-cut PC fibers.
• the appearance of the obtained fibers was good with no fluff, the single fiber fineness was 2.2 dtex, the average fiber length was 15.0 mm, and the glass transition temperature (softening point of an amorphous thermoplastic resin) was 150 ° C. , and the specific gravity was 1.2 g/cm 3 .
• Example 1 Preparation of expandable layer 50 wt% PEI fibers as thermoplastic fibers, 45 wt% glass fibers with a cut length of 13 mm (manufactured by Nippon Electric Glass Co., Ltd.: average fiber diameter 10.5 ⁇ m, specific gravity 2.54 g/cm 3 ) as reinforcing fibers, and PET-based binder as binder fibers. 5 wt % of fibers were put into 1.5 L of water and 40 mL of dispersant, and stirred 1500 times at 540 rpm using a disintegrator to prepare a slurry. 60 to 80 mL of a thickener was added to the obtained slurry, and an expandable layer precursor having a basis weight of 35 g/m 2 was obtained by a wet-laid process.
• PEI film manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 100 ⁇ m, softening point (Ti) 217°C
• the PEI film/expandable precursor was laminated and heated at 240°C for 5 minutes using a test press machine (KVHC-II manufactured by Kitagawa Seiki) while applying pressure at 5 MPa in the lamination direction. After thermocompression bonding, the insulating sheet was produced by cooling to room temperature while maintaining the pressure. The thickness of the obtained insulating sheet was 148 ⁇ m.
• the obtained insulating sheet was placed in a constant temperature incubator (DN411H manufactured by Yamato Scientific Co., Ltd.) set at 260°C, which is above the softening point of the thermoplastic resin, and heated for 10 minutes, then taken out and cooled to 25°C. Insulating material was obtained by doing this. The thickness of the obtained insulating material was 219 ⁇ m.
• Various evaluations were performed on the obtained insulating material, and the evaluation results are shown in Tables 1 and 2.
• the set temperature of the constant temperature incubator for expansibility evaluation was 260°C
• the set temperature of the constant temperature incubator for punching load test was 280°C
• the gap height h of the sample for punching load test was 200 ⁇ m. And so.
• Example 2 In the production process of the insulating sheet, the insulating material was made in the same manner as in Example 1, except that the insulating layer was a commercially available liquid crystal polyester film (manufactured by Kuraray Co., Ltd., Vector CTF, thickness 100 ⁇ m, melting point (Ti) 280°C). Obtained. The thickness of the obtained insulating sheet was 158 ⁇ m, and the thickness of the insulating material was 249 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• the insulating layer was a commercially available liquid crystal polyester film (manufactured by Kuraray Co., Ltd., Vector CTF, thickness 100 ⁇ m, melting point (Ti) 280°C). Obtained. The thickness of the obtained insulating sheet was 158 ⁇ m, and the thickness of the insulating material was 249 ⁇ m.
• the obtained insulating material was evaluated in the same manner as in Example 1, and the
• Example 3 In the step of producing the expandable precursor, insulation was carried out in the same manner as in Example 1, except that the glass fibers were carbon fibers with a cut length of 13 mm (manufactured by Toho Tenax: average fiber diameter 7 ⁇ m, specific gravity 1.82 g/cm 3 ). I got the material. The thickness of the obtained insulating sheet was 151 ⁇ m, and the thickness of the insulating material was 239 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 4 An insulating sheet was obtained in the same manner as in Example 1 except that the thermoplastic fibers were used as PC fibers in the step of producing the expandable precursor. The thickness of the obtained insulating sheet was 156 ⁇ m. Thereafter, the obtained insulating sheet was placed in a constant temperature incubator (DN411H manufactured by Yamato Scientific Co., Ltd.) set at 190°C, which is higher than the softening point of the thermoplastic resin, for 10 minutes, and then taken out and heated to 25°C. An insulating material was obtained by cooling to The thickness of the obtained insulating material was 230 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2. The set temperature of the constant temperature incubator for expansivity evaluation was 190°C, the set temperature of the constant temperature incubator for punching load test was 210°C, and the gap height h of the sample for punching load test was 200 ⁇ m. And so.
• Example 5 50 wt% PEI fibers as thermoplastic fibers, 45 wt% glass fibers with a cut length of 13 mm (manufactured by Nippon Electric Glass Co., Ltd.: average fiber diameter 10.5 ⁇ m, specific gravity 2.54 g/cm 3 ) as reinforcing fibers, and PET-based binder as binder fibers. 5 wt % of fibers were put into 1.5 L of water and 40 mL of dispersant, and stirred 1500 times at 540 rpm using a disintegrator to prepare a slurry.
• the obtained mixed nonwoven fabric was made into a single layer and heated at 240°C for 10 minutes while applying pressure at 5 MPa in the thickness direction of the nonwoven fabric using a test press machine (KVHC-II manufactured by Kitagawa Seiki). After heating and impregnating the molten PEI polymer and PET polymer between the glass fibers, the expandable layer is cooled to 150°C, which is below the glass transition temperature of the PEI polymer, while maintaining pressure. Created.
• the average thickness of the obtained expandable layer was 53 ⁇ m, the average basis weight was 80.2 g/m 2 , and the density was 1.51 g/cm 3 .
• the obtained expandable layer was made into an expandable layer/PEI film using a commercially available PEI film (manufactured by Mitsubishi Chemical Corporation, Superio UI F type, thickness 100 ⁇ m, softening point (Ti) 217°C) as an insulating layer.
• An insulating sheet (expandable layer/PEI film laminate) and an insulating material were obtained in the same manner as in Example 1 except that they were overlapped.
• the thickness of the obtained insulating sheet was 153 ⁇ m, and the thickness of the insulating material was 286 ⁇ m.
• the obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 6 An insulating sheet was obtained in the same manner as in Example 1 except that the fabric weight was 80 g/m 2 in the step of producing the expandable precursor. The thickness of the obtained insulating sheet was 226 ⁇ m, and the thickness of the insulating material was 439 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, except that the gap height h of the sample for the punching load test was 240 ⁇ m, and the evaluation results are shown in Tables 1 and 2. Note that the void layer porosity/insulating layer thickness (Y/X) was evaluated based on the value of the punching load test sample. However, regarding the dielectric breakdown voltage, since it is difficult to measure the dielectric breakdown voltage of the sample for the punch-out load test after expansion, the dielectric breakdown charge was evaluated for the sample expanded under no load. The same applies to Examples 7 to 14 below.
• Example 7 In the process of producing an insulating sheet, the same procedure as Example 1 was performed except that a commercially available PEI film (manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 50 ⁇ m, softening point (Ti) 217°C) was used as the insulating layer. An insulating material was obtained in the same manner. The thickness of the obtained insulating sheet was 158 ⁇ m, and the thickness of the insulating material was 249 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 8 The same procedure as Example 1 was carried out, except that the insulating layer was a commercially available PEI film (manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 200 ⁇ m, softening point (Ti) 217° C.) in the insulating sheet manufacturing process. An insulating sheet was obtained in the same manner. The thickness of the obtained insulating sheet was 245 ⁇ m, and the thickness of the insulating material was 335 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, except that the gap height h of the sample for the punching load test was 250 ⁇ m, and the evaluation results are shown in Tables 1 and 2.
• Example 9 In the process of producing an insulating sheet, the same procedure as Example 1 was performed except that a commercially available PEI film (manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 20 ⁇ m, softening point (Ti) 217°C) was used as the insulating layer. An insulating sheet was obtained in the same manner. The thickness of the obtained insulating sheet was 71 ⁇ m, and the thickness of the insulating material was 124 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, except that the gap height h of the sample for the punching load test was 100 ⁇ m, and the evaluation results are shown in Tables 1 and 2.
• Example 10 Preparation of insulating layer
• a commercially available PEI film manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 50 ⁇ m, softening point (Ti) 217°C
• glass fiber fabric manufactured by Unitika Corporation, equivalent to IPC standard 1037
• KVHC-II manufactured by Kitagawa Seiki
• the thickness of the obtained insulating layer was 98 ⁇ m. (Preparation of insulation sheet) Thereafter, an insulating sheet was obtained in the same manner as in Example 1. The thickness of the obtained insulating sheet was 144 ⁇ m, and the thickness of the insulating material was 208 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 11 50 wt% PEI fibers as thermoplastic fibers, 45 wt% glass fibers with a cut length of 13 mm (manufactured by Nippon Electric Glass Co., Ltd.: average fiber diameter 10.5 ⁇ m, specific gravity 2.54 g/cm 3 ) as reinforcing fibers, and PET-based binder as binder fibers. 5 wt % of fibers were put into 1.5 L of water and 40 mL of dispersant, and stirred 1500 times at 540 rpm using a disintegrator to prepare a slurry. 60 to 80 mL of a thickener was added to the obtained slurry, and an expandable layer precursor having a basis weight of 35 g/m 2 was obtained by a wet-laid process.
• the obtained mixed nonwoven fabric was made into a single layer and heated at 240°C for 10 minutes while applying pressure at 5 MPa in the thickness direction of the nonwoven fabric using a test press machine (KVHC-II manufactured by Kitagawa Seiki). After heating and impregnating the molten PEI polymer and PET polymer between the glass fibers, the expandable layer is cooled to 150°C, which is below the glass transition temperature of the PEI polymer, while maintaining pressure. Created.
• the average thickness of the obtained expandable layer was 53 ⁇ m, the average basis weight was 80.2 g/m 2 , and the density was 1.51 g/cm 3 .
• the obtained expandable layer was prepared by using a commercially available liquid crystal polyester film (manufactured by Kuraray Co., Ltd., Vector CTF, thickness 100 ⁇ m, melting point (Ti) 280°C) as an insulating layer to form an expandable layer/LCP film/expandable layer.
• a test press machine KVHC-II manufactured by Kitagawa Seiki
• the thickness of the obtained insulating sheet was 151 ⁇ m.
• an insulating material was produced in the same manner as in Example 1.
• the thickness of the obtained insulating material was 181 ⁇ m.
• the obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 12 An insulating sheet and an insulating material were produced in the same manner as in Example 11, except that the obtained expandable layer was heated at 260° C. for 5 minutes and bonded by thermocompression. The thickness of the obtained insulating sheet was 148 ⁇ m, and the thickness of the insulating material was 166 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 13 An insulating sheet was obtained in the same manner as in Example 2 except that the thermoplastic fibers were used as PP fibers in the step of producing the expandable precursor. The thickness of the obtained insulating sheet was 149 ⁇ m. Thereafter, the obtained insulating sheet was placed in a constant temperature incubator (“DN411H” manufactured by Yamato Scientific Co., Ltd.) set at 190°C, which is higher than the melting point (Tb: 161°C) of the thermoplastic resin constituting the expandable layer. After heating for 10 minutes, the mixture was taken out and cooled to 25° C. to obtain an insulating material. The thickness of the obtained insulating material was 203 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• Example 14 An insulating sheet was obtained in the same manner as in Example 2 except that the thermoplastic fibers were used as PA6 fibers in the step of producing the expandable precursor. The thickness of the obtained insulating sheet was 145 ⁇ m. Thereafter, the obtained insulating sheet was placed in a constant temperature incubator ("DN411H” manufactured by Yamato Scientific Co., Ltd.) set at 260 °C, which is higher than the melting point (Tb: 225 °C) of the thermoplastic resin constituting the expandable layer. After heating for 10 minutes, the mixture was taken out and cooled to 25° C. to obtain an insulating material. The thickness of the obtained insulating material was 222 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• the obtained insulating sheet was placed in a constant temperature incubator (DN411H manufactured by Yamato Scientific Co., Ltd.) set at a predetermined temperature above the softening point of the thermoplastic resin and heated for 10 minutes, then taken out and cooled to 25°C. Insulating material was obtained by doing this. The thickness of the insulating material was 709 ⁇ m. Evaluation was performed in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2.
• An expandable layer precursor was obtained in the same manner as in Example 1 except that the basis weight was 80 g/m 2 .
• Each of the obtained expandable layer precursors was made into an expandable precursor/film by using a commercially available liquid crystal polyester film (manufactured by Kuraray Co., Ltd., Vector CTF, thickness 100 ⁇ m, melting point (Ti) 280°C) as an insulating layer.
• a test press machine KVHC-II manufactured by Kitagawa Seiki
• heat at 300°C for 5 minutes while applying pressure at 5 MPa in the stacking direction to thermocompression bond and then press. It was cooled to room temperature while maintaining the temperature, and an insulating sheet was produced.
• the thickness of the obtained insulating sheet was 165 ⁇ m, and the thickness of the insulating material was 182 ⁇ m.
• the obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2. However, as in Example 1, although the gap height h of the sample for the punching load test was set to 200 ⁇ m, the punching load test was not performed because it could not be filled.
• Comparative example 4 An insulating sheet was produced in the same manner as in Comparative Example 3, except that the insulating layer was a commercially available PEI film (manufactured by Mitsubishi Chemical Corporation, Superio UT F type, thickness 100 ⁇ m, softening point (Ti) 217° C.). The thickness of the obtained insulating sheet was 154 ⁇ m, and the thickness of the insulating material was 182 ⁇ m. The obtained insulating material was evaluated in the same manner as in Example 1, and the evaluation results are shown in Tables 1 and 2. However, as in Example 1, although the gap height h of the sample for the punching load test was set to 200 ⁇ m, the punching load test was not performed because it could not be filled.
• the gap height h of the sample for the punching load test was set to 200 ⁇ m, the punching load test was not performed because it could not be filled.
• the insulating material cannot form a void layer due to expansion because it does not have an expandable layer. Moreover, in Comparative Example 2, although it expands, it is inferior in dielectric breakdown voltage. Further, in Comparative Examples 3 and 4, the porosity of the void layer and the thickness of the insulating layer of the insulating material after expansion were not within the predetermined ranges, so the dielectric breakdown voltage was inferior to that of the example. On the other hand, in all of Examples 1 to 5, the insulating material is formed by expansion, and the insulating material after expansion has an extremely large value of insulation compared to Comparative Example 2, although it has voids. Indicates breakdown voltage. In particular, it shows good insulation performance regardless of the retention rate of the thermoplastic resin constituting the void layer at room temperature and softening temperature.
• the insulating material of the present invention is useful in various applications because it can not only insulate but also fix a conductive material.
• the insulating material is particularly useful as an insulating material for a rotating electrical machine, a cable covering material, an electrical wiring covering material, etc. used in a rotating electrical machine.

Landscapes

• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Laminated Bodies (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=87934979

Family Applications (1)

Country Status (4)

Cited By (1)

Citations (5)

Family Cites Families (3)

• 2023
  • 2023-03-03 WO PCT/JP2023/008026 patent/WO2023171562A1/ja not_active Ceased
  • 2023-03-03 JP JP2024506281A patent/JP7751724B2/ja active Active
  • 2023-03-03 EP EP23766738.1A patent/EP4492644A4/en active Pending
  • 2023-03-07 TW TW112108325A patent/TW202344378A/zh unknown

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events