JP2011111498A - Resin sheet and laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin sheet with excellent handleability and also excellent thermal conductivity and processability, and a laminate. <P>SOLUTION: The resin sheet 2 includes a (meth)acrylic polymer (A), a first inorganic filler (B) having thermal conductivity of 10 W/m.K or more and new Mohs hardness of 3.1 or more, and at least one material (C) of an organic resin filler (C1) and a second inorganic filler (C2) having new Mohs hardness of 3 or less. In the resin sheet 2, the content of the first inorganic filler (B) is 20-60 vol% and the content of the material (C) is 1-40 vol%. The laminate 1 includes the resin sheet 2, a heat-generating component 3 laminated on one side 2a of the resin sheet 2, and a metal housing or heat-radiating component 4 laminated on another side 2b of the resin sheet 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to, for example, a resin sheet that can be used for bonding a heat generating component to a metal casing or a heat radiating component, and a laminate using the resin sheet.

  In recent years, miniaturization and high performance of electric devices have been advanced. Along with this, the mounting density of electronic components is increasing, and the need to dissipate heat generated from electronic components is increasing. As a method of dissipating heat, a method of adhering a heat conductor such as aluminum having high heat dissipation and a thermal conductivity of 10 W / m · K or more to a heat source is widely adopted. In addition, an insulating adhesive material having an insulating property is used to bond the heat conductor to a heat source. Insulating adhesive materials are strongly required to have high thermal conductivity.

  As an example of the above-mentioned insulating adhesive material, the following patent document 1 discloses an insulating adhesive in which a glass cloth is impregnated with an adhesive composition containing an epoxy resin, an epoxy resin curing agent, a curing accelerator, an elastomer and an inorganic filler. A sheet is disclosed.

  Insulating adhesive materials that do not contain glass cloth are also known. For example, the example of Patent Document 2 below includes an insulating adhesive containing bisphenol A type epoxy resin, phenoxy resin, phenol novolak, 1-cyanoethyl-2-phenylimidazole, γ-glycidoxypropyltrimethoxysilane, and alumina. Agents are disclosed.

JP 2006-342238 A JP-A-8-332696

  In the insulating adhesive sheet described in Patent Document 1, a glass cloth is used in order to improve handling properties. With an insulating adhesive sheet including glass cloth, it is difficult to make a thin film, and various processes such as laser processing or drilling are difficult. Moreover, since the heat conductivity of the hardened | cured material of the insulation adhesive sheet containing a glass cloth is comparatively low, sufficient heat dissipation may not be obtained. Furthermore, special impregnation equipment must be prepared for impregnating the glass cloth with the adhesive composition.

  In the insulating adhesive described in Patent Document 2, since glass cloth is not used, the sheet itself is not self-supporting in an uncured state. For this reason, the handling property of the insulating adhesive may be low.

  An object of the present invention is to provide a resin sheet that is excellent in handling properties, and further excellent in thermal conductivity and processability, and a laminate using the resin sheet.

  According to a wide aspect of the present invention, a (meth) acrylic polymer (A) and a first inorganic filler having a thermal conductivity of 10 W / m · K or more and a new Mohs hardness of 3.1 or more ( B) and at least one substance (C) of the organic resin filler (C1) and the second inorganic filler (C2) having a new Mohs hardness of 3 or less, and the first inorganic filler (B ) Is 20 to 60% by volume, and the content of the substance (C) is 1 to 40% by volume.

  In a specific aspect of the resin sheet according to the present invention, the substance (C) is the second inorganic filler (C2), and the first inorganic filler (B) and the second inorganic filler (C2). Satisfies the following formula (X).

  [{(New Mohs hardness of first inorganic filler (B)) × (content of first inorganic filler (B) in 100% by volume of resin sheet (% by volume))} + {(second inorganic filler New Mohs hardness of (C2)) × (content of second inorganic filler (C2) in 100% by volume of resin sheet (% by volume))}] <6 Formula (X)

  In another specific aspect of the resin sheet according to the present invention, the substance (C) is the second inorganic filler (C2), and the second inorganic filler (C2) is diatomaceous earth, boron nitride, hydroxide. It is at least one selected from the group consisting of aluminum, magnesium hydroxide, calcium carbonate, talc, kaolin, clay and mica.

  In still another specific aspect of the resin sheet according to the present invention, the first inorganic filler (B) includes alumina, synthetic magnesite, crystalline silica, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, and magnesium oxide. At least one selected from the group consisting of

  The glass transition temperature of the (meth) acrylic polymer (A) is preferably 25 ° C. or lower.

  A laminate according to the present invention includes a resin sheet configured according to the present invention, a heat generating component laminated on one surface of the resin sheet, and a metal housing or heat radiating component laminated on the other surface of the resin sheet. With.

  The resin sheet according to the present invention includes a (meth) acrylic polymer (A), a first inorganic filler (B) having a thermal conductivity of 10 W / m · K or more and a new Mohs hardness of 3.1 or more. ) And at least one substance (C) of the organic resin filler (C1) and the second inorganic filler (C2) having a new Mohs hardness of 3 or less, and further the first inorganic filler (B ) And the content of the substance (C) are within the specific range, and thus handling properties are excellent. Furthermore, the thermal conductivity and workability of the resin sheet can be improved.

FIG. 1 is a partially cutaway front sectional view schematically showing an example of a laminate using a resin sheet according to an embodiment of the present invention.

  Details of the present invention will be described below.

  The resin sheet according to the present invention includes a (meth) acrylic polymer (A), a first inorganic filler (B) having a thermal conductivity of 10 W / m · K or more and a new Mohs hardness of 3.1 or more. ) And at least one substance (C) among the organic resin filler (C1) and the second inorganic filler (C2) having a new Mohs hardness of 3 or less.

  By adopting the above composition, the inventors of the present application have high thermal conductivity and high workability, particularly by using the first inorganic filler (B) and the substance (C) at the specific content. I found out that they can be compatible. Moreover, since the resin sheet which concerns on this invention has the said composition, it is excellent also in handling property, and also can suppress an excessive flow at the time of lamination | stacking press.

((Meth) acrylic polymer (A))
The (meth) acrylic polymer (A) contained in the resin sheet according to the present invention is not particularly limited as long as it is a polymer having a (meth) acryloyl group. As for (meth) acrylic-type polymer (A), only 1 type may be used and 2 or more types may be used together.

  In addition, (meth) acryl shows acrylic and methacryl. (Meth) acryloyl refers to acryloyl and methacryloyl.

  The (meth) acrylic polymer can be obtained by polymerizing (meth) acrylic acid or (meth) acrylic acid ester. Examples of this polymerization reaction include a free radical polymerization reaction, a living radical polymerization reaction, and a living anion polymerization reaction. These polymerization reactions can be initiated by applying energy such as heat, ultraviolet rays or electron beams. Examples of the polymerization means include bulk polymerization, solution polymerization, soap-free polymerization, suspension polymerization, and emulsion polymerization. In polymerization, a reaction initiator may be used. The (meth) acrylic polymer (A) may be synthesized by reacting (meth) acrylic acid or (meth) acrylic acid ester after sheet forming.

  Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, tert-butyl (meth) acrylate, and cyclohexyl (meth). Acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (Meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate and tetrahydrofurfuryl (meth) acrylate Doors and the like. Only 1 type may be used for these (meth) acrylic acid esters, and 2 or more types may be used together.

  When synthesizing the (meth) acrylic polymer, other monomers than the above-described (meth) acrylic acid or (meth) acrylic acid ester may be used. As for another monomer, only 1 type may be used and 2 or more types may be used together.

  Specific examples of the other monomer include, for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- Hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 3-hydroxy-3-methylbutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, Examples include pentaerythritol tri (meth) acrylate, 2-[(meth) acryloyloxy] ethyl 2-hydroxyethylphthalic acid, and 2-[(meth) acryloyloxy] ethyl 2-hydroxypropylphthalic acid.

  Examples of the other monomers include (meth) acrylonitrile derivatives, N-vinyl derivatives, (meth) acrylic acid derivatives, maleic anhydride, maleimidic acid derivatives, styrene, styrene derivatives, and vinyl ester derivatives.

  Examples of the N-vinyl derivative include N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylcaprolactone and N-vinylpiperidine. Examples of the (meth) acrylic acid derivative include epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) acrylate.

  Examples of the styrene derivative include indene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butoxystyrene, p-chloromethylstyrene, p-acetoxystyrene, divinylbenzene, and the like.

  Examples of the vinyl ester derivative include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, and vinyl cinnamate.

  From the viewpoint of further increasing the adhesive strength of the resin sheet, the (meth) acrylic polymer preferably has a functional group capable of crosslinking reaction. Examples of the functional group capable of crosslinking reaction include a hydroxyl group, a carboxyl group, an epoxy group, a vinyl group, and an isocyanate group. From the viewpoint of further enhancing the adhesive strength of the resin sheet, the (meth) acrylic polymer (A) preferably has a hydroxyl group, a carboxyl group, or an epoxy group.

  The weight average molecular weight of the (meth) acrylic polymer (A) is preferably 10,000 or more. The preferred lower limit for the weight average molecular weight of the (meth) acrylic polymer (A) is 30,000, the more preferred lower limit is 40,000, the still more preferred lower limit is 100,000, the preferred upper limit is 1,500,000, and the more preferred upper limit is 1,000,000. When the weight average molecular weight of the (meth) acrylic polymer (A) satisfies the above preferable lower limit, the cohesive force of the resin sheet can be sufficiently obtained, and the handling property can be further enhanced. When the weight average molecular weight of the (meth) acrylic polymer (A) satisfies the above preferable upper limit, sufficient flexibility can be obtained, and adhesion between the resin sheet, the heat generating component and the heat radiating component can be improved. As a result, heat dissipation can be further enhanced.

  The glass transition temperature of the (meth) acrylic polymer (A) is preferably 25 ° C. or lower. The upper limit of the glass transition temperature of the (meth) acrylic polymer (A) is preferably 15 ° C, more preferably 10 ° C, and still more preferably 0 ° C. When the glass transition temperature of the (meth) acrylic polymer (A) satisfies the above preferable upper limit, sufficient flexibility can be obtained, and adhesion between the resin sheet, the heat generating component, and the heat dissipation component can be improved.

  The content of the (meth) acrylic polymer (A) is in the range of 50 to 100% by weight in a total of 100% by weight of all resin components contained in the resin sheet containing the (meth) acrylic polymer (A). Preferably there is. The more preferable lower limit of the content of the (meth) acrylic polymer (A) in the total 100% by weight of all the resin components is 70% by weight. When content of (meth) acrylic-type polymer (A) satisfy | fills the said preferable minimum, the adhesive force of a resin sheet can be improved further. In addition, a 1st inorganic filler (B) and a substance (C) are not contained in all the resin components. The total resin component does not include the organic resin filler (C1) and the second inorganic filler (C2).

  When the below-mentioned crosslinking agent (D) is used, the preferable upper limit of the content of the (meth) acrylic polymer (A) in the total 100% by weight of all the resin components is 99.99% by weight, more preferably the upper limit. Is 99.97% by weight.

  When the compound (E) having a cyclic ether skeleton described later is used, the preferable upper limit of the content of the (meth) acrylic polymer (A) in the total 100% by weight of all the resin components is 99% by weight, more A preferred upper limit is 97% by weight.

  When a cross-linking agent (D) described later and a compound (E) having a cyclic ether skeleton are used, the content of the (meth) acrylic polymer (A) in the total 100% by weight of all the resin components is preferable. The upper limit is 99.99 wt%, and the more preferable upper limit is 98.97 wt%. A more preferred upper limit is 96.99% by weight, and a most preferred upper limit is 96.97% by weight.

(First inorganic filler (B))
The first inorganic filler (B) contained in the resin sheet according to the present invention has a thermal conductivity of 10 W / m · K or more and a new Mohs hardness of 3.1 or more. By using this first inorganic filler (B), the thermal conductivity of the resin sheet can be increased. As a result, the heat dissipation of the resin sheet is increased. As for a 1st inorganic filler (B), only 1 type may be used and 2 or more types may be used together.

  When the thermal conductivity of the first inorganic filler (B) is 10 W / m · K or more, the thermal conductivity of the resin sheet can be sufficiently increased. When the thermal conductivity of the first inorganic filler (B) is smaller than 10 W / m · K, it is difficult to sufficiently increase the thermal conductivity of the resin sheet. A preferable lower limit of the thermal conductivity of the first inorganic filler (B) is 15 W / m · K, and a more preferable lower limit is 20 W / m · K. The upper limit of the thermal conductivity of the first inorganic filler (B) is not particularly limited. Inorganic fillers having a thermal conductivity of about 300 W / m · K are widely known, and inorganic fillers having a thermal conductivity of about 200 W / m · K are easily available.

  The new Mohs hardness of the first inorganic filler (B) is 3.1 or more. When such a 1st inorganic filler (B) is used, the workability of a resin sheet tends to fall. However, the addition amount of the first inorganic filler (B) is limited to a certain range, and together with the first inorganic filler (B) to compensate for the shortage of the first inorganic filler (B), Substance (C) is used. For this reason, the workability of the resin sheet can be sufficiently ensured without sacrificing the thermal conductivity of the resin sheet. The preferable lower limit of the new Mohs hardness of the first inorganic filler (B) is 4, and the preferable upper limit is 14. When the new Mohs hardness of the first inorganic filler (B) satisfies the above preferable upper limit, the high thermal conductivity and high workability of the resin sheet can be achieved at a higher level.

  The first inorganic filler (B) is preferably at least one selected from the group consisting of alumina, synthetic magnesite, crystalline silica, aluminum nitride, silicon nitride, silicon carbide, zinc oxide and magnesium oxide. By using these preferable first inorganic fillers (B), the heat dissipation of the resin sheet can be further enhanced.

  The first inorganic filler (B) is more preferably at least one selected from the group consisting of spherical alumina, crushed alumina, and spherical aluminum nitride, and more preferably spherical alumina or spherical aluminum nitride. In this case, the heat dissipation of the resin sheet can be further enhanced.

  The first inorganic filler (B) may be a spherical filler or a crushed filler.

  Examples of the crushed filler include crushed alumina. The crushed filler can be obtained, for example, by crushing a massive inorganic substance using a uniaxial crusher, a biaxial crusher, a hammer crusher, a ball mill, or the like. By using the crushed filler, the first inorganic filler (B) in the resin sheet is likely to be bridged or have a structure in which the filler is efficiently brought close. Therefore, the thermal conductivity of the resin sheet can be further enhanced. Moreover, the crushed filler is generally cheaper than a normal filler. For this reason, the cost of the resin sheet can be reduced by using the crushed filler.

  The average particle size of the crushed filler is preferably 12 μm or less. When the average particle size is 12 μm or less, the crushed filler can be dispersed with high density, and the dielectric breakdown characteristics of the resin sheet can be further enhanced. The preferable upper limit of the average particle diameter of the crushed filler is 10 μm, and the preferable lower limit is 1 μm. When the average particle diameter of the crushed filler satisfies the above preferable lower limit, the crushed filler can be filled more densely.

  The aspect ratio of the crushed filler is not particularly limited. The aspect ratio of the crushed filler is preferably in the range of 1.5-20. Fillers with an aspect ratio of less than 1.5 are relatively expensive. When the aspect ratio is 20 or less, filling of the crushed filler is easy.

  The aspect ratio of the crushed filler can be determined, for example, by measuring the crushed surface of the filler using a digital image analysis type particle size distribution measuring device (trade name: FPA, manufactured by Nippon Luft).

  When the first inorganic filler (B) is a spherical filler, the average particle diameter of the spherical filler is preferably in the range of 0.1 to 40 μm. When the average particle size is 0.1 μm or more, the spherical filler can be filled at a high density. When the average particle size is 40 μm or less, the dielectric breakdown characteristics of the resin sheet can be further enhanced.

  The “average particle diameter” is an average particle diameter obtained from a volume average particle size distribution measurement result measured by a laser diffraction particle size distribution measuring apparatus.

  Content of the 1st inorganic filler (B) in 100 volume% of resin sheets exists in the range of 20-60 volume%. When the content of the first inorganic filler (B) is less than 20% by volume, the heat dissipation of the resin sheet may not be sufficiently improved. When content of a 1st inorganic filler (B) exceeds 60 volume%, there exists a possibility that the workability of a resin sheet may fall. The preferable lower limit of the content of the first inorganic filler (B) in 100% by volume of the resin sheet is 30% by volume, the more preferable lower limit is 35% by volume, the preferable upper limit is 57% by volume, and the more preferable upper limit is 55% by volume. The preferred upper limit is 50% by volume, and the most preferred upper limit is 40% by volume. In 100% by volume of the resin sheet, the total content of the first inorganic filler (B) and the substance (C) is less than 100% by volume, preferably less than 90% by volume, more preferably less than 80% by volume, More preferably, it is less than 70 volume%. If the said preferable upper limit is satisfy | filled, the softness | flexibility of a resin sheet will be fully obtained and the adhesiveness of a resin sheet, a heat-emitting component, and a thermal radiation component can be improved. Moreover, the adhesive force of the resin sheet can be further enhanced. In 100% by volume of the resin sheet, the total content of the first inorganic filler (B) and the substance (C) is preferably 21% by volume or more, more preferably 30% by volume or more, and 35% by volume. % Or more is more preferable. When the preferable lower limit is satisfied, the resin sheet can be prevented from excessively flowing during the lamination press. Moreover, the handling property of the resin sheet can be further enhanced.

(Substance (C))
The substance (C) contained in the resin sheet according to the present invention is at least one of the organic resin filler (C1) and the second inorganic filler (C2) having a new Mohs hardness of 3 or less. As the substance (C), only the organic resin filler (C1) may be used, or only the second inorganic filler (C2) may be used. The organic resin filler (C1) and the second inorganic filler (C2) ) May be used. When the content of the first inorganic filler (B) is in the above-mentioned range, a problem that sufficient handling properties cannot be obtained or the resin sheet tends to flow during the lamination press tends to occur. However, in the resin sheet according to the present invention, since the substance (C) is contained at a constant content together with the first inorganic filler (B), the above-mentioned problems are solved without reducing the workability of the resin sheet. can be solved. As a result, for example, when the resin sheet is punched or drilled, wear of the mold can be suppressed. As for a substance (C), only 1 type may be used and 2 or more types may be used together.

  Since the organic resin filler (C1) is formed of a resin, the flexibility is relatively high. Therefore, by using the organic resin filler (C1), it is possible to impart handling properties without lowering the workability of the resin sheet, and to suppress the resin sheet from excessively flowing during the lamination press.

  Since the processability of the resin sheet is not deteriorated, the handling property is imparted, the excessive flow of the resin sheet can be suppressed at the time of laminating press, and the heat dissipation and heat resistance of the resin sheet can be further enhanced. (C) is preferably the second inorganic filler (C2).

  When the new Mohs hardness of the second inorganic filler (C2) is 3 or less, the processability of the resin sheet can be sufficiently enhanced. If the new Mohs hardness of the second inorganic filler (C2) is 3.1 or more, the processability of the resin sheet may be lowered. The preferable upper limit of the new Mohs hardness of the second inorganic filler (C2) is 2.8, the more preferable upper limit is 2.0, and the preferable lower limit is 1.

  The organic resin filler (C1) is preferably insoluble particles including a repeating structure formed of monomers. The monomer is preferably an acrylic monomer or a styrene monomer. As for an acryl-type monomer and a styrene-type monomer, only 1 type may respectively be used and 2 or more types may be used together.

  Examples of the acrylic monomer include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, acrylate-2-ethylhexyl, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, Butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate Can be mentioned.

  Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, and pn-. Butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2,4-dimethyl Examples include styrene and 3,4-dichlorostyrene.

  The organic resin filler (C1) preferably has a core-shell structure. By using the organic resin filler having a core-shell structure, the heat resistance of the resin sheet can be further enhanced. The organic resin filler having a core-shell structure has a core layer and a shell layer covering the core layer. The core layer and the shell layer covering the core layer are preferably acrylic compounds.

  The organic resin filler (C1) is preferably a composite filler containing a compound having a skeleton in which oxygen atoms are directly bonded to silicon atoms and an organic substance. In this case, the heat resistance of the resin sheet can be further enhanced.

  The core layer preferably contains a compound having a skeleton in which oxygen atoms are directly bonded to silicon atoms. The shell layer preferably contains an organic substance. The organic resin filler (C1) is preferably a composite filler having a core layer containing a compound having a skeleton in which an oxygen atom is directly bonded to the silicon atom, and a shell layer containing the organic substance.

  The compound having a skeleton in which an oxygen atom is directly bonded to the silicon atom is preferably a siloxane polymer. The organic material is preferably an acrylic compound.

  The average particle diameter of the organic resin filler (C1) is preferably in the range of 0.1 to 40 μm. When the average particle diameter of the organic resin filler (C1) is 0.1 μm or more, the organic resin filler (C1) can be filled at a higher density. The heat resistance of a resin sheet can be improved further as the average particle diameter of an organic resin filler (C1) is 40 micrometers or less.

  The substance (C) is the second inorganic filler (C2), and the second inorganic filler (C2) is from diatomaceous earth, boron nitride, aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, kaolin, clay and mica. More preferably, it is at least one selected from the group consisting of talc. By using this second inorganic filler (C2), the processability of the resin sheet can be further enhanced.

  The second inorganic filler (C2) may be a spherical filler or a crushed filler.

  When the second inorganic filler (C2) is a spherical filler, the preferable lower limit of the average particle diameter of the spherical filler is 0.1 μm, the more preferable lower limit is 0.5 μm, the preferable upper limit is 40 μm, and the more preferable upper limit is 20 μm. When the average particle diameter of the second inorganic filler (C2) satisfies the preferable lower limit, the second inorganic filler (C2) can be filled at a higher density. When the average particle diameter of the second inorganic filler (C2) satisfies the preferable upper limit, the dielectric breakdown characteristics of the resin sheet can be further enhanced.

  The “average particle diameter” is an average particle diameter obtained from a volume average particle size distribution measurement result measured by a laser diffraction particle size distribution measuring apparatus.

  Content of the substance (C) in 100 volume% of resin sheets exists in the range of 1-40 volume%. If the content of the substance (C) is less than 1% by volume, excessive flow of the resin sheet may not be sufficiently suppressed during the lamination press. When the content of the substance (C) exceeds 40% by volume, the total addition amount of the first inorganic filler (B) and the substance (C) is excessively increased, so that the dielectric breakdown characteristics of the resin sheet are deteriorated. Or the resin sheet becomes hard and brittle, and the handleability and adhesiveness of the resin sheet may be reduced. A preferable lower limit of the content of the substance (C) in 100% by volume of the resin sheet is 3% by volume, a more preferable lower limit is 5% by volume, a further preferable lower limit is 10% by volume, a preferable upper limit is 30% by volume, and a more preferable upper limit is 20%. % By volume.

  Moreover, when a resin sheet contains only an organic resin filler (C1) as a substance (C), the minimum with preferable content of the organic resin filler (C1) in 100 volume% of resin sheets is 3 volume%, and a more preferable minimum Is 5% by volume, a more preferred lower limit is 10% by volume, a preferred upper limit is 30% by volume, and a more preferred upper limit is 20% by volume.

  Moreover, when a resin sheet contains only the 2nd inorganic filler (C2) as a substance (C), the minimum with preferable content of the 2nd inorganic filler (C2) in 100 volume% of resin sheets is 2 volume%. A more preferred lower limit is 3% by volume, a preferred upper limit is 30% by volume, and a more preferred upper limit is 20% by volume.

  The substance (C) is the second inorganic filler (C2), and it is preferable that the first inorganic filler (B) and the second inorganic filler (C2) satisfy the following formula (X). In this case, the workability of the resin sheet can be further enhanced.

[{(New Mohs hardness of first inorganic filler (B)) × (content of first inorganic filler (B) in 100% by volume of resin sheet (% by volume))} + {(second inorganic filler New Mohs hardness of (C2)) × (content of second inorganic filler (C2) in 100% by volume of resin sheet (% by volume))}] <6 Formula (X)
The value on the right side in the formula (X) is 6, and the value on the right side in the formula (X) is preferably 5.5, and more preferably 5. That is, “<6” in the formula (X) is preferably “<5.5”, and more preferably “<5”.

(Crosslinking agent (D))
The resin sheet according to the present invention preferably further contains a crosslinking agent (D). In this case, the (meth) acrylic polymer (A) preferably has a functional group capable of crosslinking reaction. By using the crosslinking agent (D), the adhesive strength of the resin sheet can be further enhanced. As for a crosslinking agent (D), only 1 type may be used and 2 or more types may be used together.

  Examples of the crosslinking agent (D) include an isocyanate crosslinking agent, an aziridine crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent.

  From the viewpoint of further increasing the adhesive strength of the resin sheet, the crosslinking agent (D) preferably has a functional group capable of reacting with the (meth) acrylic polymer (A). Examples of the reactive functional group include an isocyanate group, an epoxy group, and an aziridine group. From the viewpoint of further enhancing the adhesive strength of the resin sheet, the crosslinking agent (D) preferably has an isocyanate group or an epoxy group.

  When the (meth) acrylic monomer is polymerized by photopolymerization, it is preferable to add a polyfunctional (meth) acrylate compound as the crosslinking agent (D). By using the crosslinking agent, crosslinking can be performed simultaneously with the polymerization of the acrylic acid alkyl ester monomer.

  Examples of the polyfunctional (meth) acrylate compound include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ( Poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol tri (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) Acrylate, and the like. As for the said polyfunctional (meth) acrylate compound, only 1 type may be used and 2 or more types may be used together.

  When the cross-linking agent (D) is used, the cross-linking agent (100% in total of all resin components contained in the resin sheet containing the (meth) acrylic polymer (A) and the cross-linking agent (D) ( The content of D) is preferably in the range of 0.01 to 10% by weight. The more preferable lower limit of the content of the crosslinking agent (D) in 100% by weight of the total resin components is 0.03% by weight, and the more preferable upper limit is 5% by weight. When content of a crosslinking agent (D) satisfy | fills the said preferable minimum, the heat resistance of a resin sheet can be improved further. When content of a crosslinking agent (D) satisfy | fills the said preferable upper limit, the adhesive force of a resin sheet can be improved further. In addition, a crosslinking agent (D) is contained in all the resin components.

(Compound having a cyclic ether skeleton (E))
The resin sheet according to the present invention preferably further contains a compound (E) having a cyclic ether skeleton. By using the compound (E) having a cyclic ether skeleton, the thermosetting property of the resin sheet can be enhanced and the adhesive force can be further enhanced. Only 1 type may be used for the compound (E) which has cyclic ether frame | skeleton, and 2 or more types may be used together.

  Examples of the compound (E) having a cyclic ether skeleton include an epoxy resin (E1) and an oxetane resin (E2). Of these, epoxy resin (E1) is preferable.

  Specific examples of the epoxy resin (E1) include an epoxy monomer having a bisphenol skeleton, an epoxy monomer having a dicyclopentadiene skeleton, an epoxy monomer having a naphthalene skeleton, an epoxy monomer having an adamantene skeleton, an epoxy monomer having a fluorene skeleton, and a biphenyl skeleton An epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton, an epoxy monomer having a xanthene skeleton, an epoxy monomer having an anthracene skeleton, an epoxy monomer having a pyrene skeleton, and the like, including at least one of them It may be a polymer.

  Examples of the epoxy monomer having a bisphenol skeleton include an epoxy monomer having a bisphenol skeleton of bisphenol A type, bisphenol F type, and bisphenol S type.

  Examples of the epoxy monomer having a dicyclopentadiene skeleton include dicyclopentadiene dioxide and a phenol novolac epoxy monomer having a dicyclopentadiene skeleton, and a polymer containing at least one of them may be used.

  Examples of the epoxy monomer having a naphthalene skeleton include 1-glycidylnaphthalene, 2-glycidylnaphthalene, 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidyl. Naphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, 1,2,5,6-tetraglycidylnaphthalene and the like may be mentioned, and a polymer containing at least one of them may be used.

  Examples of the epoxy monomer having an adamantene skeleton include 1,3-bis (4-glycidyloxyphenyl) adamanten, 2,2-bis (4-glycidyloxyphenyl) adamanten, and the like, which includes at least one kind thereof. It may be combined.

  Examples of the epoxy monomer having a fluorene skeleton include 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3-methylphenyl) fluorene, and 9,9-bis (4- Glycidyloxy-3-chlorophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-bromophenyl) fluorene, 9,9-bis (4-glycidyloxy-3-fluorophenyl) fluorene, 9,9-bis (4-Glycidyloxy-3-methoxyphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dimethylphenyl) fluorene, 9,9-bis (4-glycidyloxy-3,5-dichlorophenyl) Fluorene and 9,9-bis (4-glycidyloxy-3,5-dibromophenyl) Fluorene, and the like, may be a polymer which contains at least one.

  Examples of the epoxy monomer having a biphenyl skeleton include 4,4′-diglycidyl biphenyl, 4,4′-diglycidyl-3,3 ′, 5,5′-tetramethylbiphenyl, and the like. It may be a polymer.

  Examples of the epoxy monomer having a bi (glycidyloxyphenyl) methane skeleton include 1,1′-bi (2,7-glycidyloxynaphthyl) methane, 1,8′-bi (2,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,7-glycidyloxynaphthyl) methane, 1,8′-bi (3,7-glycidyloxynaphthyl) methane, 1,1′-bi (3,5-glycidyloxynaphthyl) methane 1,8'-bi (3,5-glycidyloxynaphthyl) methane, 1,2'-bi (2,7-glycidyloxynaphthyl) methane, 1,2'-bi (3,7-glycidyloxynaphthyl) Examples thereof include methane and 1,2′-bi (3,5-glycidyloxynaphthyl) methane, and a polymer containing at least one of them may be used.

  Examples of the epoxy monomer having a xanthene skeleton include 1,3,4,5,6,8-hexamethyl-2,7-bis-oxiranylmethoxy-9-phenyl-9H-xanthene, and at least one of them. It may be a polymer containing seeds.

  Specific examples of the oxetane resin (E2) include, for example, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylate bis [(3-ethyl-3- Oxetanyl) methyl] ester, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] benzene, oxetated phenol novolak, and the like, and a polymer containing at least one of them may be used.

  When the compound (E) having a cyclic ether skeleton is used, the total of all resin components contained in the resin sheet containing the (meth) acrylic polymer (A) and the compound (E) having a cyclic ether skeleton In 100% by weight, the content of the compound (E) having a cyclic ether skeleton is preferably in the range of 1 to 50% by weight. The more preferable lower limit of the content of the compound (E) having a cyclic ether skeleton in 100% by weight of the total resin components is 3% by weight, and the more preferable upper limit is 30% by weight. When content of the compound (E) which has cyclic ether frame | skeleton satisfy | fills the said preferable minimum, the adhesive force of a resin sheet can be improved further. When the content of the compound (E) having a cyclic ether skeleton satisfies the above preferable upper limit, the cohesive force of the (meth) acrylic polymer (A) can be sufficiently ensured. In addition, the compound (E) which has cyclic ether skeleton is contained in all the resin components.

(Other ingredients)
The resin sheet according to the present invention may include rubber particles that are not included in the organic resin filler (C1). By using the rubber particles, the stress relaxation property and flexibility of the resin sheet can be enhanced.

  The resin sheet according to the present invention may contain a dispersant. By using the dispersant, the thermal conductivity and dielectric breakdown characteristics of the resin sheet can be further enhanced.

  The dispersant preferably has a functional group containing a hydrogen atom having hydrogen bonding properties. When the dispersing agent has a functional group containing a hydrogen atom having hydrogen bonding properties, the thermal conductivity and dielectric breakdown characteristics of the resin sheet can be further enhanced. Examples of the functional group containing a hydrogen atom having hydrogen bonding include a carboxyl group (pKa = 4), a phosphate group (pKa = 7), a phenol group (pKa = 10), and the like.

  The preferable lower limit of the pKa of the functional group containing a hydrogen atom having hydrogen bonding properties is 2, a more preferable lower limit is 3, a preferable upper limit is 10, and a more preferable upper limit is 9. When the pKa of the functional group satisfies the preferable lower limit, the acidity of the dispersant does not become too high. Therefore, the storage stability of the resin sheet can be further enhanced. When pKa of the said functional group satisfy | fills the said preferable upper limit, the function as the said dispersing agent will fully be fulfilled and the thermal conductivity and dielectric breakdown characteristic of a resin sheet can be improved further.

  The functional group containing a hydrogen atom having hydrogen bonding properties is preferably a carboxyl group or a phosphate group. In this case, the thermal conductivity and dielectric breakdown characteristics of the resin sheet can be further enhanced.

  Specific examples of the dispersant include a polyester carboxylic acid, a polyether carboxylic acid, a polyacrylic carboxylic acid, an aliphatic carboxylic acid, a polysiloxane carboxylic acid, a polyester phosphoric acid, and a polyether type. Examples thereof include phosphoric acid, polyacrylic phosphoric acid, aliphatic phosphoric acid, polysiloxane phosphoric acid, polyester phenol, polyether phenol, polyacrylic phenol, aliphatic phenol, and polysiloxane phenol. As for the said dispersing agent, only 1 type may be used and 2 or more types may be used together.

  In 100% by weight of the resin sheet, a preferable lower limit of the content of the dispersant is 0.01% by weight, a more preferable lower limit is 0.1% by weight, a preferable upper limit is 20% by weight, and a more preferable upper limit is 10% by weight. When the content of the dispersant satisfies the preferable lower limit and upper limit, aggregation of the first filler (B) or the substance (C) can be suppressed, and the thermal conductivity and dielectric breakdown characteristics of the resin sheet can be sufficiently enhanced. Can do.

  The resin sheet according to the present invention may contain a base material such as glass cloth, glass nonwoven fabric, and aramid nonwoven fabric in order to further improve handling properties. However, even if the base material is not included, the resin sheet according to the present invention has a self-supporting property at room temperature (23 ° C.) and an excellent handling property. Therefore, it is preferable that the resin sheet does not include a base material, and particularly it does not include glass cloth. When the resin sheet does not contain the base material, the thickness of the resin sheet can be reduced and the thermal conductivity of the resin sheet can be further enhanced. Furthermore, when the resin sheet does not contain the above-mentioned base material, various processes such as laser processing or drilling can be easily performed on the resin sheet as necessary. In addition, self-supporting means that the shape of a sheet can be maintained and handled as a sheet even when a support such as a PET film or a copper foil is not present.

  Moreover, the resin sheet which concerns on this invention may contain the hardening | curing agent, the coupling agent, the thixotropy imparting agent, the flame retardant, the coloring agent, etc. as needed.

(Resin sheet)
The method for producing the resin sheet according to the present invention is not particularly limited. The resin sheet can be obtained, for example, by forming a mixture of the above-described materials into a sheet shape by a method such as a solvent casting method or an extrusion film forming method. Defoaming is preferred when forming into a sheet.

  The thickness of the resin sheet is not particularly limited. The thickness of the resin sheet is preferably in the range of 10 to 300 μm. A more preferable lower limit of the thickness of the resin sheet is 50 μm, a further preferable lower limit is 70 μm, a more preferable upper limit is 120 μm, and a further preferable upper limit is 100 μm. When the thickness of the resin sheet satisfies the above preferable lower limit, the insulating property of the resin sheet becomes high. When the thickness of the resin sheet satisfies the above preferable upper limit, the heat dissipation of the resin sheet is further enhanced.

  The glass transition temperature Tg of the resin sheet is preferably 25 ° C. or lower. When the glass transition temperature is 25 ° C. or lower, the resin sheet is hard and hardly brittle at room temperature. For this reason, the handleability of the resin sheet can be further enhanced.

  The thermal conductivity of the resin sheet is preferably 0.7 W / m · K or more, more preferably 1.0 W / m · K or more, and further preferably 1.5 W / m · K or more. preferable. The higher the thermal conductivity, the higher the heat dissipation of the resin sheet.

  The dielectric breakdown voltage of the resin sheet is preferably 30 kV / mm or more, more preferably 40 kV / mm or more, further preferably 50 kV / mm or more, and further preferably 80 kV / mm or more. More preferably, it is 100 kV / mm or more. The higher the dielectric breakdown voltage, the higher the insulation is when the resin sheet is used for large current applications such as for power elements.

(Laminate)
The resin sheet which concerns on this invention is used suitably for adhere | attaching a heat-emitting component, a metal housing | casing, or a thermal radiation component.

  In FIG. 1, an example of the laminated body using the resin sheet which concerns on one Embodiment of this invention is shown typically.

  A laminated body 1 shown in FIG. 1 includes a resin sheet 2, a heat generating component 3 laminated on one surface 2 a of the resin sheet 2, and a heat radiating component 4 laminated on the other surface 2 b of the resin sheet 2. A metal housing may be used in place of the heat dissipation component 4. The resin sheet 2 is disposed between the heat generating component 3 and the heat radiating component 4. The heat generating component 3 and the heat radiating component 4 are bonded by the resin sheet 2.

  Specific examples of the heat generating component 3 include a CPU and a board.

  Specific examples of the heat dissipating component 4 or the metal housing include a heat spreader and a heat sink.

  The heat dissipation component 4 is preferably a heat conductor having a thermal conductivity of 10 W / m · K or more. Examples of the heat conductor include aluminum, copper, alumina, beryllia, silicon carbide, silicon nitride, aluminum nitride, and graphite sheet. Especially, it is preferable that the said heat conductor is copper or aluminum. Copper or aluminum is excellent in heat dissipation.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. The present invention is not limited to the following examples.

  The following materials were prepared.

[(Meth) acrylic polymer (A)]
(1) Hydroxyl group and carboxyl group-containing acrylic polymer (manufactured by Nagase ChemteX Corporation, trade names: WS-023, Mw = 500,000, Tg = −5 ° C.)
(2) Epoxy group-containing acrylic polymer 1 (manufactured by Nagase ChemteX Corporation, trade name: SG-80H, Mw = 350,000, Tg = 7.5 ° C.)
(3) Carboxyl group-containing acrylic polymer (manufactured by Nagase ChemteX Corporation, trade name: SG-280, Mw = 900,000, Tg = -30.9 ° C.)
(4) Hydroxyl group-containing acrylic polymer (manufactured by Nagase ChemteX Corp., trade name: SG-600LB, Mw = 1,200,000, Tg = -31.4 ° C.)
(5) Epoxy group-containing acrylic polymer 2 (manufactured by Nagase ChemteX Corporation, trade name: SG-P3, Mw = 850,000, Tg = 15.0 ° C.)

[First inorganic filler (B)]
(1) Spherical alumina (Denka Co., Ltd., trade name: DAM-10, average particle size 10 μm, thermal conductivity 36 W / m · K, new Mohs hardness 12)
(2) Crushed alumina (trade name: LS-242C, manufactured by Nippon Light Metal Co., Ltd., average particle diameter 2 μm, thermal conductivity 36 W / m · K, new Mohs hardness 12)
(3) Synthetic magnesite (Kamishima Chemical Co., Ltd., trade name: MSL, average particle size 6 μm, thermal conductivity 15 W / m · K, new Mohs hardness 3.5)
(4) Aluminum nitride (manufactured by Toyo Aluminum Co., Ltd., trade name: TOYALNITE-FLX, average particle size 14 μm, thermal conductivity 200 W / m · K, new Mohs hardness 11)
(5) Crystalline silica (manufactured by Tatsumori Co., Ltd., trade name: Crystallite CMC-12, average particle size 5 μm, thermal conductivity 10 W / m · K, new Mohs hardness 7)
(6) Silicon carbide (manufactured by Shinano Electric Smelting Co., Ltd., trade name: Shinano Random GP # 700, average particle diameter 17 μm, thermal conductivity 125 W / m · K, new Mohs hardness 13)
(7) Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name: LPZINC-5, average particle size 5 μm, thermal conductivity 54 W / m · K, new Mohs hardness 5)
(8) Magnesium oxide (manufactured by Sakai Chemical Industry Co., Ltd., trade name: SMO Large Particle, average particle size 1.1 μm, thermal conductivity 35 W / m · K, new Mohs hardness 6)

[Organic resin filler (C1)]
(1) 0.1 μm particles (core shell type silicone-acrylic particles, manufactured by Asahi Kasei Wacker Silicone Co., Ltd., trade name: P22, average particle size 0.1 μm, having a core shell structure, a skeleton in which oxygen atoms are directly bonded to silicon atoms (Including core layer containing compound and organic matter)
(2) 0.5 μm particles (core-shell type organic particles, manufactured by Ganz Kasei Co., Ltd., trade name: AC-3355, average particle size 0.5 μm, having a core-shell structure)
(3) 4 μm particles (acrylic particles, manufactured by Ganz Kasei Co., Ltd., trade name: GM-0401S, average particle diameter 4 μm)

[Second inorganic filler (C2)]
(1) Mica (manufactured by Yamaguchi Mica Industry Co., Ltd., trade name: SJ005, average particle diameter 5 μm, new Mohs hardness 2.8)
(2) Talc (Nippon Talc Co., Ltd., trade name: K-1, average particle diameter 8 μm, new Mohs hardness 1)
(3) Boron nitride (manufactured by Showa Denko KK, trade name: UHP-1, average particle size 8 μm, new Mohs hardness 2)
(4) Clay (manufactured by Shiraishi Calcium Co., Ltd., trade name: ST-301, average particle size 0.7 μm, new Mohs hardness 2)
(5) Kaolin (manufactured by BASF, trade name: ASP-400P, average particle size 4.8 μm, new Mohs hardness 2.8)
(6) Aluminum hydroxide (manufactured by Nippon Light Metal Co., Ltd., trade name: B-103, average particle diameter 8 μm, new Mohs hardness 3)
(7) Magnesium hydroxide (manufactured by Tateho Chemical Co., Ltd., trade name: PZ-1, average particle size 1.2 μm, new Mohs hardness 2.5)
(8) Calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., trade name: BF-300, average particle size 8 μm, new Mohs hardness 3)
(9) Diatomaceous earth (manufactured by Shiraishi Calcium Co., Ltd., trade name: ST-C219, average particle size 9 μm, new Mohs hardness 1.5)

[Other inorganic fillers]
(1) Fused silica (trade name: SE15, average particle size 15 μm, thermal conductivity 2 W / m · K, new Mohs hardness 7 manufactured by Tokuyama Corporation)

[Crosslinking agent (D)]
(1) Isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L)
(2) Bisphenol A type epoxy crosslinking agent (product name: Epicoat 828US, manufactured by Japan Epoxy Resin Co., Ltd.)

[Compound having a cyclic ether skeleton (E)]
(1) Epoxy group-containing styrene resin (manufactured by NOF Corporation, trade name: Marproof G-1010S, Mw = 100,000, Tg = 93 ° C.)

[Curing agent]
(1) Isocyanur-modified solid dispersion type imidazole (imidazole curing accelerator, manufactured by Shikoku Kasei Co., Ltd., trade name: 2MZA-PW)

[Dispersant]
(1) Acrylic dispersant (manufactured by Big Chemie Japan, trade name: Disperbyk-2070, pKa has a carboxyl group of 4)
(2) Polyether-based dispersant (manufactured by Enomoto Kasei Co., Ltd., trade name: ED151, pKa has 7 phosphate groups)

[Additive]
(1) Epoxysilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBE403)

[solvent]
(1) Methyl ethyl ketone

(Examples 1-33 and Comparative Examples 1-7)
Using a homodisper type stirrer, each raw material was blended in the proportions (blending units are parts by weight) shown in Tables 1 to 5 below, and kneaded to prepare an insulating varnish.

  The resin varnish was applied to a release PET sheet having a thickness of 50 μm so as to have a thickness of 100 μm and dried in an oven at 90 ° C. for 30 minutes to prepare a resin sheet on the PET sheet.

(Evaluation)
(1) Handling property A laminate sheet having a PET sheet and a resin sheet formed on the PET sheet was cut into a size of 460 mm x 610 mm to obtain a test sample. Using the obtained test sample, the handling property when the resin sheet was peeled from the PET sheet at room temperature (23 ° C.) was evaluated according to the following criteria.
[Handling criteria]
○: The resin sheet is not deformed and can be easily peeled. Δ: Although the resin sheet can be peeled, the sheet is stretched or broken. ×: The resin sheet cannot be peeled.

(2) Thermal conductivity The thermal conductivity of the resin sheet was measured using a thermal conductivity meter “rapid thermal conductivity meter QTM-500” manufactured by Kyoto Electronics Industry Co., Ltd.

(3) Workability A resin sheet sandwiched between two PET films having a thickness of 50 μm was punched out using a mold having a diameter of 20 mm (manufactured by Tsukaya Knife Manufacturing Co., Ltd., Pinnacle Die RDC (FB)). The number of times until the flash was generated was measured, and the punching workability was evaluated according to the following criteria.
[Criteria for workability]
◎: Possible to process 100 times or more without occurrence of burr ○: Possible to process 50 times or more and less than 100 times without occurrence of burr △: Possible to process 10 times or more and less than 50 times without occurrence of burr ×: 10 Burrs are generated by machining less than once

(4) Extrusion amount at the time of lamination press After cutting out the lamination sheet which has a PET sheet and the resin sheet formed on this PET sheet in the magnitude | size of 13 cm x 5 cm, the resin sheet was peeled from the PET sheet. In addition, an aluminum plate having a size of 13 cm × 5 cm (manufactured by Engineering Test Service, JISH4000 A5052P, maximum height roughness Rz 1.1 μm), and a copper foil having a size of 13 cm × 5 cm (manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., An electrolytic copper foil, CT-T8) was prepared.

  A resin sheet was sandwiched between the rough surface of the aluminum plate and the rough surface of the copper foil to obtain a laminate, and then pressed at 23 ° C. and a pressure of 4 MPa for 10 minutes. The weight of the resin sheet protruding from the side surface of the laminate after pressing was measured, and the amount of protrusion of the resin sheet was determined by the following formula. The amount of protrusion was determined according to the following criteria.

Amount of protrusion = (weight of resin sheet protruding from side surface of laminate after pressing) / (weight of resin sheet before pressing) × 100
[Criteria for protruding amount]
○: The protruding amount of the resin sheet is less than 7%. Δ: The protruding amount of the resin sheet is more than 7% and less than 10%. X: The protruding amount of the resin sheet is 10% or more. (5) Adhesive strength The resin sheet is 20 mm × 100 mm. A test sample was obtained by cutting into a size. An aluminum foil having a thickness of 50 μm was attached to one surface of the test sample, and then an aluminum test piece was attached to the other surface of the test sample. Next, it was allowed to stand at 23 ° C. and a relative humidity of 65% RH for 30 minutes to obtain a laminate. Using a tensile tester (manufactured by A & D Co., Ltd., universal tester Tensilon RTF), the laminate resin and aluminum foil were peeled from the aluminum test piece, and the 90 ° peel force was measured. The measured value was defined as the adhesive strength of the resin sheet.

(6) Dielectric breakdown voltage The resin sheet was cut out to a size of 100 mm × 100 mm to obtain a test sample. Using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics), an alternating voltage was applied between the resin sheets so that the voltage increased at a rate of 1 kV / second. The voltage at which the resin sheet was broken was taken as the dielectric breakdown voltage.

  The results are shown in Tables 1 to 5 below.

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Resin sheet 2a ... One side 2b ... The other side 3 ... Heat generating component 4 ... Heat radiating component

Claims (6)

(Meth) acrylic polymer (A),
A first inorganic filler (B) having a thermal conductivity of 10 W / m · K or higher and a new Mohs hardness of 3.1 or higher;
Containing at least one substance (C) of the organic resin filler (C1) and the second inorganic filler (C2) having a new Mohs hardness of 3 or less,
The resin sheet whose content of the said 1st inorganic filler (B) is 20-60 volume%, and whose content of the said substance (C) is 1-40 volume%. The substance (C) is the second inorganic filler (C2);
The resin sheet according to claim 1, wherein the first inorganic filler (B) and the second inorganic filler (C2) satisfy the following formula (X).
[{(New Mohs hardness of first inorganic filler (B)) × (content of first inorganic filler (B) in 100% by volume of resin sheet (% by volume))} + {(second inorganic filler New Mohs hardness of (C2)) × (content of second inorganic filler (C2) in 100% by volume of resin sheet (% by volume))}] <6 Formula (X) The substance (C) is the second inorganic filler (C2);
The second inorganic filler (C2) is at least one selected from the group consisting of diatomaceous earth, boron nitride, aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, kaolin, clay and mica. Or the resin sheet of 2.   The first inorganic filler (B) is at least one selected from the group consisting of alumina, synthetic magnesite, crystalline silica, aluminum nitride, silicon nitride, silicon carbide, zinc oxide, and magnesium oxide. The resin sheet of any one of 1-3.   The resin sheet of any one of Claims 1-4 whose glass transition temperature of the said (meth) acrylic-type polymer (A) is 25 degrees C or less. The resin sheet according to any one of claims 1 to 5,
A heat generating component laminated on one surface of the resin sheet;
A laminate comprising a metal casing or a heat dissipation component laminated on the other surface of the resin sheet.

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