Resin composition and heat dissipation member

Abstract

Provided is a resin composition comprising a matrix resin having an alkyl group on a molecular side chain, an inorganic filler, and an antioxidant, the antioxidant being any one of a hydrazide-based antioxidant, or a combination of a hindered phenol-based antioxidant and an organic metal chelate-based antioxidant.

Description

Technical Field

[0001] The present invention relates to a heat dissipating component used in electronic equipment and the like, and a resin composition for forming the heat dissipating component. Background Art

[0002] In electronic devices, integrated electronic components generate heat, which can lead to malfunctions. Therefore, heat sinks are sometimes installed to dissipate the heat generated by the electronic components to the outside of the device. In recent years, with the miniaturization and increased performance of electrical equipment, there has been a demand for material technologies that maintain electrical insulation while efficiently dissipating the heat generated during operation. One method for increasing thermal conductivity has traditionally been to increase the filler content. For example, Patent Document 1 discloses a thermally conductive silicone composition containing 200 to 2500 parts by mass of a thermally conductive filler per 100 parts by mass of an organopolysiloxane.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6194861 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, conventional thermally conductive silicone compositions cannot maintain sufficient heat dissipation performance when used for a long time in a high-temperature environment.

[0008] Therefore, an object of the present invention is to provide a resin composition having high long-term reliability even in a high-temperature environment.

[0009] Means of solving the problem

[0010] The present inventors conducted extensive research and discovered that the failure of a resin composition to maintain heat dissipation performance during long-term use in high-temperature environments is due to oxidative degradation of the resin caused by metallic impurities, particularly iron and manganese ions, present on the surface of the highly loaded filler in the composition. Furthermore, the inventors discovered that the addition of an antioxidant with a specific structure can resolve this problem.

[0011] That is, the present invention provides the following [1] to [7].

[0012] [1] A resin composition comprising a base resin, an inorganic filler, and an antioxidant, wherein the antioxidant is a hydrazide antioxidant or a combination of a hindered phenol antioxidant and a chelate antioxidant.

[0013] [2] The resin composition according to [1], wherein the chelate antioxidant is a hydrazide antioxidant.

[0014] [3] The resin composition according to [1] or [2], wherein the base resin has an alkyl group on a side chain of the molecule.

[0015] [4] The resin composition according to any one of [1] to [3], wherein the inorganic filler comprises at least one selected from diamond and cubic boron nitride.

[0016] [5] The resin composition according to any one of [1] to [4], wherein the matrix resin is at least one selected from silicone resins, epoxy resins, and acrylic resins.

[0017] [6] A heat dissipating component formed from the resin composition according to any one of [1] to [5].

[0018] [7] An electronic device comprising an electronic component and the heat dissipation component described in [6] provided on the electronic component.

[0019] Effects of the Invention

[0020] According to the present invention, a resin composition having high long-term reliability even in a high-temperature environment can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic perspective view showing the shape of an inorganic filler.

[0022] Figure 2 This is a schematic perspective view showing the shape of a polyhedral filler in an inorganic filler. DETAILED DESCRIPTION

[0023] [Resin composition]

[0024] Hereinafter, the resin composition of the present invention will be described in detail.

[0025] The resin composition of the present invention comprises a matrix resin, an inorganic filler, and an antioxidant. These components are described in detail below.

[0026] (Antioxidant)

[0027] The resin composition of the present invention includes an antioxidant. In the present invention, the antioxidant is any one of a combination of a hydrazide antioxidant, a hindered phenol antioxidant, and a chelate antioxidant. These specific antioxidants can capture metal cations, particularly iron ions and manganese ions, which are metal impurities on the surface of the inorganic filler, or capture free radicals generated by the metal impurities, thereby suppressing the oxidative degradation of the resin. Therefore, for a resin composition comprising an inorganic filler, by including the above-mentioned specific antioxidant, the long-term reliability when used in a high-temperature environment can be improved. Therefore, even when used in a high-temperature environment, degradation and hardness rise can also be suppressed. In addition, even if the resin composition is kept at a higher temperature for a long time, degradation can also be suppressed, and storage stability also becomes good.

[0028] As described above, the resin composition of the present invention, in one embodiment, contains a hindered phenolic antioxidant and a chelate antioxidant. In the present invention, the combined use of a hindered phenolic antioxidant and a chelate antioxidant can significantly improve long-term reliability when used in high-temperature environments. While the mechanism for this is uncertain, it is speculated that the chelate antioxidant chelates and inactivates metal cations attached to the surface of the inorganic filler, while the hindered phenolic antioxidant captures free radicals, preventing oxidation of the matrix resin, thereby significantly improving long-term reliability.

[0029] <Hindered phenol antioxidants>

[0030] Hindered phenolic antioxidants are compounds that have a steric hindering group such as a tert-butyl group on the carbon atom adjacent to the carbon atom to which the phenolic hydroxyl group is bonded on the phenyl group. Note that the phenolic hydroxyl group refers to a hydroxyl group that is directly bonded to the phenyl group.

[0031] The molecular weight of the hindered phenolic antioxidant is preferably 300 or greater, more preferably 500 or greater, and even more preferably 700 or greater. By setting the molecular weight of the hindered phenolic antioxidant to be greater than the above lower limit, the hindered phenolic antioxidant in the resin composition is less likely to volatilize, and the hindered phenolic antioxidant's effect is readily exhibited over a long period of time even when used in a high-temperature environment. Furthermore, from the perspective of appropriately capturing free radicals and readily suppressing oxidative degradation of the resin, the molecular weight of the hindered phenolic antioxidant is preferably 2000 or less, more preferably 1500 or less, and even more preferably 1200 or less.

[0032] In hindered phenolic antioxidants, the hydroxyl groups (phenolic hydroxyl groups) bonded to the phenyl group generally capture free radicals to prevent oxidation, so a large number is preferred. Therefore, hindered phenolic antioxidants may have 1 or more phenolic hydroxyl groups, preferably 2 or more, and more preferably 3 or more. The number of phenolic hydroxyl groups is not particularly limited, and may be 6 or less, or 4 or less, for example.

[0033] The phenol equivalent of the hindered phenol antioxidant is preferably 140 or greater, more preferably 160 or greater, and even more preferably 200 or greater. Furthermore, from the perspective of appropriately capturing free radicals and easily suppressing oxidative degradation of the resin, the phenol equivalent is preferably 1000 or less, more preferably 600 or less, and even more preferably 300 or less. Among these, hindered phenol antioxidants particularly preferably have a molecular weight of 700 or greater and a phenol equivalent of 300 or less.

[0034] The phenol equivalent is a value obtained by dividing the molecular weight of the hindered phenolic antioxidant by the number of phenolic hydroxyl groups per molecule of the hindered phenolic antioxidant.

[0035] Specific examples of hindered phenol antioxidants include 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 4,4',4"-(1-methylpropyl-3-ylidene)tris(6-tert-butyl-m-cresol), 1,1,3-tris-(2'-methyl-4'-hydroxy-5'-tert-butylphenyl)-butane, 4,4'-butylene-bis-(2-tert-butyl-5-methylphenol), stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3-[tert-butyl-5-hydroxyphenyl]propionate], and 1,3,5-tris(2'-methyl-4'-hydroxy-5'-tert-butylphenyl)-butane. ,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylmethyl)-2,4,6-trimethylbenzene, 1,3,5-tris(3-hydroxy-4-tert-butyl-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-thiodiethylbis-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, N , N-hexamethylenebis(3,5-di-tert-butyl-4-hydroxy-hydrocinnamic acid), octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 4,6-bis(dodecylthiomethyl)-o-cresol, calcium salt of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid monoethyl ester, 4,6-bis(octylthiomethyl)-o-cresol, 6,6'-di-tert-butyl-4,4'-butylene di-m-cresol, bis[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propionic acid]ethylenedioxybisethylene, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,4-bis(n-octylthio)-6- (4-Hydroxy-3,5-di-tert-butylanilino)-1,3,5-triazine, 2,2'-thio-bis(6-tert-butyl-4-methylphenol), 2,5-di-tert-amyl-hydroquinone, 2,6-di-tert-butyl-4-nonylphenol, 2,2'-isobutylene-bis(4,6-dimethylphenol), 2,2'-methylene-bis(6-(1-methyl-cyclohexyl)-p-cresol), 2,4-dimethyl-6-(1-methyl-cyclohexyl)phenol, 2,6-di-tert-butyl-4-methylphenol, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl]propionohydrazide, etc.

[0036] Commercially available hindered phenol antioxidants may also be used. Examples of commercially available products include ADEKA Stab AO-20, AO-30, AO-40, AO-50, AO-60, AO-80, AO-330, and CDA-10 manufactured by ADEKA, KEMINOX 101, 179, 76, and 9425 manufactured by Chemipro, SEENOX 224M manufactured by Dipro Chemicals, Irganox 1010, 1035, 1076, 1098, 1135, 1330, 1726, 1425WL, 1520L, 245, 259, 3114, 5057, and 565 manufactured by BASF Japan, and Sianox CY-1790 and CY-2777 manufactured by San Chemicar.

[0037] <Chelated antioxidants>

[0038] As the chelate antioxidant used in combination with the hindered phenol antioxidant, a chelate antioxidant without a hindered phenol structure can be used, and specifically, hydrazide antioxidants and organic chelate antioxidants other than hydrazide antioxidants (hereinafter also referred to as "organic chelate antioxidants") can be used. Among them, hydrazide antioxidants are preferred.

[0039] As the chelate antioxidant, as long as it is an organic chelate, the molecular weight is preferably more than 80, more preferably more than 90, and further preferably more than 100. When the molecular weight of the chelate antioxidant is above the above lower limit, the chelate antioxidant deactivates metal impurities such as manganese on the surface of the inorganic filler, easily improving the long-term reliability of the resin combination under a high temperature environment. In addition, from the perspective of easily deactivating the metal impurities, the molecular weight of the chelate antioxidant is preferably less than 700, more preferably less than 600, and further preferably less than 550.

[0040] Hydrazide antioxidants

[0041] The hydrazide antioxidant may be any compound having a hydrazide structure, and as described above, any compound not having a hindered phenol structure may be used. The hydrazide antioxidant is preferably a dihydrazide compound having two hydrazide structures.

[0042] Specifically, the hydrazide antioxidant is preferably a compound represented by the following general formula (1).

[0043]

[0044] In the above formula (1), R 1 and R 2Each independently represents an organic group having 1 to 20 carbon atoms. 3 It represents a divalent hydrocarbon group having 1 to 20 carbon atoms.

[0045] In the above formula (1), R 3 It is preferably a saturated aliphatic group, more preferably -(CH2)n-. n represents an integer of 1 to 20, and n is preferably 2 to 15, more preferably 4 to 14, and further preferably 5 to 12. R 1 and R 2 It can be a hydrocarbon group or a hydrocarbon group having heteroatoms such as nitrogen atoms, oxygen atoms, and sulfur atoms. 1 and R 2 When there is a heteroatom, as R 1 and R 2 , hydrocarbon groups having ether bonds, ester bonds, amide bonds, thiol bonds, urethane bonds, urea bonds, hydroxyl groups, etc. can be cited. 1 and R 2 The number of carbon atoms is preferably 2 to 15, more preferably 3 to 10, and even more preferably 5 to 8. 1 and R 2 In terms of improving long-term reliability, an aromatic group having a phenolic hydroxyl group is preferred.

[0046] In the above formula (1), R 1 and R 2 It can be an aliphatic group such as an alkyl group or a hydroxyalkyl group, or an aromatic group. As for the aromatic group, as long as it has an aromatic ring, phenyl, naphthyl, methylphenyl, ethylphenyl, benzyl, hydroxyphenyl, hydroxynaphthyl, hydroxymethylphenyl, hydroxyethylphenyl and other aryl groups, benzyl, hydroxybenzyl and other aralkyl groups can be mentioned. Among them, R is preferably 1 and R 2 Both are aromatic groups having a phenolic hydroxyl group, and hydroxyphenyl is particularly preferred.

[0047] Examples of hydrazide antioxidants include N'1,N'12-bis(2-hydroxybenzoyl)dodecane dihydrazide, 1,9-decanedicarboxylic acid bis(N'-salicylic hydrazide), adipic acid dihydrazide, sebacic acid dihydrazide, dodecane dihydrazide, isophthalic acid dihydrazide, and salicylic acid dihydrazide.

[0048] Commercially available hydrazide antioxidants may also be used. Examples of commercially available products include ADEKA START CDA-6S, ZS-90, and ZS-91 manufactured by ADEKA Corporation.

[0049] As the organic chelate antioxidant, there is no particular limitation as long as it is a compound capable of chelating metals, and examples thereof include phthalocyanine compounds such as phthalocyanine, benzimidazole compounds such as benzimidazole and 2-methylbenzimidazole, benzothiazole compounds such as 2-alkyldithiobenzothiazole and 2-(N,N-dialkylthiocarbamoyl)benzothiazole, 2,5-bis(alkyldithio)-1,3,4-thiadiazole, 2,5- Thiadiazole compounds such as bis(N,N-dialkylthiocarbamoyl)-1,3,4-thiadiazole, pyrazole compounds such as pyrazole and 3,5-dimethylpyrazole, triazole compounds such as 2-hydroxy-N-1H-1,2,4-triazol-3-yl-benzamide, 1,3,5-triazine-2,4,6-triamine, ethylenediaminetetraacetic acid, N,N'-disalicylidene-1,2-propylenediamine, alizarin, tetraalkyldithiosemicarbazide, etc.

[0050] Among them, phthalocyanine compounds, benzimidazole compounds, and pyrazole compounds are preferred.

[0051] Commercially available organic chelate antioxidants may also be used, and examples of commercially available products include CDA-1 and ZS-27 manufactured by ADEKA, and EDTA and phthalocyanine manufactured by TCI.

[0052] In one embodiment of the present invention, the resin composition includes a hydrazide antioxidant as an antioxidant. In this case, the resin composition can sufficiently improve long-term reliability even without including a hindered phenolic antioxidant. The mechanism for this is not yet clear, but it is speculated that the hydrazide antioxidant can fully inactivate metal impurities attached to the surface of the inorganic filler, thereby sufficiently improving long-term reliability even without a hindered phenolic antioxidant.

[0053] However, from the viewpoint of improving long-term reliability, the resin composition of the present invention more preferably contains a hindered phenol-based antioxidant as an antioxidant in addition to the hydrazide-based antioxidant.

[0054] The content of the antioxidant in the resin combination of the present invention, based on the gross mass of the composition (hereinafter, also referred to as " resin composition ") except the inorganic filler in the resin combination, is preferably more than 0.01 mass %, more preferably more than 0.015 mass %, further preferably more than 0.1 mass %. When the content of antioxidant is above the above-mentioned lower limit, even when the resin combination is exposed to a high temperature environment, long-term reliability can be improved. In addition, from not excessively comprising antioxidant, obtaining the effect aspect commensurate with its content, based on the gross mass of the resin composition, the content of antioxidant is preferably below 4 mass %, more preferably below 2 mass %, further preferably below 1 mass %.

[0055] In addition, when a combination of a hindered phenolic antioxidant and a chelate antioxidant is included as an antioxidant, the blending ratio of the hindered phenolic antioxidant to the chelate antioxidant (hindered phenolic antioxidant / chelate antioxidant) is preferably 1 / 3 or more and 1 / 0.1 or less, more preferably 1 / 2 or more and 1 / 0.2 or less, and even more preferably 1 / 9 or more and 1 / 1 or less in terms of mass ratio. By making the hindered phenolic antioxidant / chelate antioxidant ratio within the above range, the blending balance of the hindered phenolic antioxidant and the chelate antioxidant becomes appropriate, and the effect of the antioxidant is easily exhibited. In addition, it is preferred that the content of the chelate antioxidant is greater than the content of the hindered phenolic antioxidant, and therefore, it is also preferred that the above blending ratio is less than 1 / 1.

[0056] (Base resin)

[0057] The matrix resin is a resin component that holds the inorganic filler. As a matrix resin, it can be a curable resin or a non-curable matrix resin such as a thermoplastic resin. In addition, it can also be an elastomeric resin. As a curable resin, it can be any of moisture curable, heat curable, and light curable, preferably heat curable. As a matrix resin, it is preferably a liquid component. The resin component of the liquid component can become solid by curing, or it can be non-curable and remain liquid in the heat dissipation component. It should be noted that the liquid component refers to a component that is liquid at room temperature (25°C) and normal pressure (1 atmosphere). In the case of a curable resin, the matrix resin can be any of a single-liquid curing type and a two-liquid curing type, preferably a two-liquid curing type. In the two-liquid curing type, a first liquid containing a main agent and a second liquid containing a curing agent are mixed to form a resin composition. For the two-liquid curing type, by mixing the first liquid and the second liquid, it can be cured at room temperature, for example. The matrix resin may be any material other than the material used as the dispersant described later. Therefore, it may be any material not having a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group.

[0058] The base resin constituting the resin composition of the present invention preferably has an alkyl group on its side chain. It should be noted that a base resin having an alkyl group on its side chain means that at least one side chain bonded to the main chain contains an alkyl group. The main chain may contain a cyclic structure. Furthermore, if the base resin is a curable resin, as described later, the portion that becomes a side chain after curing may contain an alkyl group.

[0059] For example, in the case of alkyl methacrylate (CH2=C(CH3)COOR, R=alkyl), the carbon double bond site (CH2=C) becomes the main chain, so the methyl group bonded to CH2=C and R become the alkyl group on the side chain of the molecule.

[0060] In the case of epoxy resins, for example, the continuous molecular chain between two epoxy groups constitutes the main chain, and thus the alkyl groups bonded to the main chain and the alkyl groups contained in the molecular chains (side chains) bonded to the main chain are the alkyl groups. As an example, in bisphenol A epoxy resins, the two methyl groups bonded to the central carbon of the bisphenol structure (-C6H4-C-C6H4-) constituting the main chain preferably constitute the alkyl groups of the side chains.

[0061] Generally, base resins having alkyl groups on the side chains of the molecules are easily oxidized and degraded by metal cations. However, in the present invention, as described above, by including a predetermined antioxidant, oxidative degradation of the resin can be suppressed, thereby improving the long-term reliability of the resin composition in a high-temperature environment.

[0062] Examples of the matrix resin include silicone resins, epoxy resins, acrylic resins, polyurethane resins, phenolic resins, polyester resins, and olefin resins.

[0063] The matrix resin may be an elastomeric resin, specifically, ethylene-propylene-diene rubber, ethylene-propylene rubber, natural rubber, polyisoprene rubber, polyester thermoplastic elastomers, polyurethane thermoplastic elastomers, styrene thermoplastic elastomers, olefin thermoplastic elastomers, etc. The elastomeric resin may be in a liquid or solid state.

[0064] The matrix resins may be used alone or in combination of two or more.

[0065] The matrix resin used in the present invention is preferably at least one selected from silicone resin, epoxy resin, acrylic resin, olefin resin, and urethane resin, among which at least one selected from silicone resin, olefin resin, epoxy resin, and acrylic resin is more preferred, further preferably at least one selected from silicone resin, epoxy resin, and acrylic resin, and particularly preferably silicone resin.

[0066] <Silicone resin>

[0067] Specific examples of silicone resins include curable silicone resins, which may be either condensation-curable silicone resins or addition-curable silicone resins, with addition-curable silicone resins being preferred.

[0068] Curable silicone resins are preferably composed of a silicone resin constituting a base component and a silicone resin constituting a curing agent that cures the base component. Furthermore, in the case of addition-curable silicone resins, the silicone resin used as the base component is preferably an organopolysiloxane containing alkenyl groups. The organopolysiloxane containing alkenyl groups may contain at least one alkenyl group, preferably two or more, and organopolysiloxanes containing approximately 2 to 10 alkenyl groups may be used.

[0069] The organopolysiloxane used as the main agent may be linear, branched, or a mixture of linear and branched ones, but is preferably linear.

[0070] The alkenyl group in the main agent may be contained in either the terminal or side chain of the molecular chain of the polysiloxane structure of the main agent, or in both the terminal and the side chain. It is preferably contained at least at the terminal, more preferably at both terminals of the molecular chain, and even more preferably only at both terminals.

[0071] The alkenyl group is not particularly limited, and examples thereof include alkenyl groups having 2 to 8 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl. Among these alkenyl groups, vinyl is preferred from the perspectives of ease of synthesis and reactivity. Furthermore, the alkenyl group may be directly bonded to a silicon atom.

[0072] In the main organopolysiloxane, the remaining groups bonded to silicon atoms other than the alkenyl groups include hydrocarbon groups that may have a substituent. Examples of the hydrocarbon groups that may have a substituent include hydrocarbon groups having approximately 1 to 20 carbon atoms, specifically alkyl groups having 1 to 20 carbon atoms, halogenated alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms.

[0073] The alkyl group may be straight-chain, branched, or cyclic. More specifically, examples include straight-chain alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; branched-chain alkyl groups such as isopropyl, tert-butyl, isobutyl, 2-methylundecyl, and 1-hexylheptyl; and cyclic alkyl groups such as cyclopentyl, cyclohexyl, and cyclododecyl.

[0074] Examples of the haloalkyl group include chloromethyl, 3,3,3-trifluoropropyl, and 3-chloropropyl. Examples of the aryl group include phenyl, tolyl, and xylyl. Examples of the aralkyl group include benzyl, phenethyl, and 2-(2,4,6-trimethylphenyl)propyl.

[0075] The organopolysiloxane constituting the main agent preferably has alkyl groups on its side chains. Therefore, the aforementioned remaining groups are preferably alkyl groups, preferably methyl groups for ease of synthesis. Furthermore, of the remaining groups bonded to silicon atoms, preferably 80 mol% or more are methyl groups, more preferably 90 mol% or more, and even more preferably 100 mol% are methyl groups. It should be noted that the organopolysiloxane constituting the main agent need not contain hydrogen atoms as the remaining groups bonded to silicon atoms, that is, it should not contain hydrosilyl groups.

[0076] The main agent may be used alone or in combination of two or more.

[0077] The viscosity of the main agent at 25°C is not particularly limited, but is preferably 20 mPa·s or more and 100,000 mPa·s or less. By setting the viscosity of the main agent to be above the above lower limit, the crosslinking density of the cured product is prevented from becoming too high, and the softness after curing is easily maintained. In addition, by setting it below the above upper limit, the resin composition can be prevented from forming a high viscosity. Furthermore, by setting the viscosity within the above range, it is easy to make the molecular weight of the main agent of an appropriate size and the reactivity appropriate. The viscosity of the main agent at 25°C is more preferably 40 mPa·s or more and 10,000 mPa·s or less, and further preferably 60 mPa·s or more and 1,000 mPa·s or less.

[0078] The hydrogen organopolysiloxane used as a curing agent may be linear or branched, or a mixture of linear and branched chains. The hydrogen organopolysiloxane may have at least one Si—H group, but preferably has two or more Si—H groups, for example, approximately 2 to 10 Si—H groups. Furthermore, the hydrogen organopolysiloxane preferably contains Si—H groups at the terminal ends.

[0079] In hydrogen organopolysiloxane, the remaining groups bonded to silicon atoms other than Si—H groups include optionally substituted hydrocarbon groups. Examples of such optionally substituted hydrocarbon groups include hydrocarbon groups having approximately 1 to 20 carbon atoms, specifically alkyl groups having 1 to 20 carbon atoms, halogenated alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, and aralkyl groups having 7 to 20 carbon atoms. Details of the alkyl, halogenated alkyl, aryl, and aralkyl groups are as described above in the main agent section.

[0080] The hydrogen organopolysiloxane preferably has an alkyl group in its side chain. Therefore, the remaining groups are preferably alkyl groups, and methyl groups are preferred from the perspective of ease of synthesis. Furthermore, of the remaining groups bonded to silicon atoms, preferably 80 mol% or more are methyl groups, more preferably 90 mol% or more are methyl groups, and even more preferably 100 mol% are methyl groups.

[0081] The curing agent may be used alone or in combination of two or more.

[0082] The viscosity of the curing agent at 25°C is not particularly limited, but is preferably 20 mPa·s or more and 100,000 mPa·s or less. By setting the viscosity of the curing agent within the above range, the crosslinking density can be prevented from becoming too high, the flexibility after curing can be maintained, and the resin composition can be prevented from forming a high viscosity. Furthermore, by setting the viscosity within the above range, it is easy to adjust the molecular weight of the curing agent to an appropriate size and the reactivity to be appropriate. The viscosity of the curing agent at 25°C is more preferably 30 mPa·s or more and 10,000 mPa·s or less, and further preferably 40 mPa·s or more and 1,000 mPa·s or less.

[0083] Alternatively, the organic silicone resin may be, for example, silicone oil. The silicone oil preferably has an alkyl group on the side chain. Examples of the silicone oil include methylphenyl silicone oil, dimethyl silicone oil, and modified silicone oil.

[0084] Silicone oil is a liquid at room temperature and normal pressure during mixing and remains in a liquid or gel-like state during use. Specifically, silicone oil is not solidified by curing agents and, even during or after curing, remains in a liquid or gel-like state, effectively a non-curable substance. Therefore, when silicone oil is used alone as a base resin or at a relatively high mixing ratio, it can create a paste-like heat dissipation component formed from a resin composition.

[0085] The silicone oil contained in the resin composition preferably has a viscosity at 25°C of 5 mPa·s to 1000 mPa·s, more preferably 30 mPa·s to 700 mPa·s, and even more preferably 100 mPa·s to 600 mPa·s. If the viscosity of the silicone oil is within the above range, the viscosity of the resin composition can be within the specified range, resulting in good coating properties and maintaining a constant shape after coating, making it easy to place on electronic components, etc. Furthermore, by properly dispersing fillers such as diamond, large amounts of the composition can be easily incorporated.

[0086] The viscosity of the silicone resin can be measured using a viscometer (BROOKFIELD Rotational Viscometer DV-E) using a rotor No. 14 at a rotation speed of 5 rpm and a measurement temperature of 25°C.

[0087] It should be noted that, when the resin composition is a curable type, as described above, it can be a single-liquid curable type or a two-liquid curable type. In the case of a two-liquid curable type, the resin composition can be obtained by mixing a first liquid containing a silicone resin as a main agent and a second liquid containing a silicone resin as a curing agent. Therefore, when the silicone resin is a single-liquid curable type or a two-liquid curable type, the resin composition preferably contains both an organopolysiloxane having an alkenyl group and an organohydrogenpolysiloxane.

[0088] Furthermore, the curable resin composition may contain a non-curable organopolysiloxane as the silicone resin, and for example, in addition to the above-mentioned organopolysiloxane having an alkenyl group or organopolysiloxane having a hydrosilyl group, may also contain silicone oil, etc. Of course, the resin composition may also be a non-curable silicone resin composition, in which case, for example, silicone oil may be used alone as the silicone resin.

[0089] <Olefin resin>

[0090] Examples of the olefin resin include polypropylene resin, polyethylene resin, poly-1-butene resin, and polypentene resin. Among them, polyethylene resin and polypropylene resin are preferred.

[0091] The polyethylene resin is not particularly limited, and examples thereof include low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene. Examples of the linear low-density polyethylene include ethylene / α-olefin copolymers such as ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers, ethylene / 4-methyl-1-pentene copolymers, and ethylene / 1-octene copolymers.

[0092] In the linear low-density polyethylene, a portion of the structural unit derived from an α-olefin other than ethylene preferably forms an alkyl group constituting the side chain. In this case, as a polyethylene resin other than the linear low-density polyethylene, a polyethylene resin having a branched portion of its molecular structure can be used, and it can be said that the branched portion is an alkyl group in the side chain.

[0093] The polypropylene resin is not particularly limited, and examples thereof include propylene homopolymers (homopolypropylene) and copolymers of propylene and other olefins. The copolymers of propylene and other olefins may be block copolymers, random copolymers, or random block copolymers, with random copolymers (random polypropylene) being preferred.

[0094] Examples of other olefins copolymerized with propylene include α-olefins such as ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, and 1-decene, with ethylene being preferred. Therefore, ethylene-propylene random copolymers are more preferred. In the polypropylene resin, the content of structural units derived from other olefins may be, for example, 10% by mass or less, preferably 1 to 8% by mass, and more preferably 2 to 6% by mass.

[0095] In polypropylene resins, it is preferred that a portion of the structural units derived from propylene constitute an alkyl group (methyl group) in the side chain. In addition, when an olefin other than ethylene is used, it is also preferred that a portion of the structural units derived from the olefin other than ethylene constitute an alkyl group in the side chain.

[0096] In poly-1-butene resins and polypentene resins, it is also preferred that a part of the structural unit derived from 1-butene or a part of the structural unit derived from pentene constitute an alkyl group in the side chain.

[0097] <Epoxy resin>

[0098] As the epoxy resin used as the matrix resin, an epoxy compound having at least one, preferably two or more epoxy groups can be used. The epoxy compound is a curable resin and is generally a thermosetting resin.

[0099] Examples of epoxy compounds include bisphenol type, novolac type, naphthalene type, trisphenol alkane type, biphenyl type, cycloaliphatic type, halides thereof, hydrides thereof, etc. As the epoxy compound, an epoxy compound having an alkyl group in a side chain is preferably used.

[0100] While epoxy compounds can be used alone as epoxy resins, epoxy resins preferably contain the aforementioned epoxy compounds as the main agent and a curing agent. Curing agents can be either polyaddition-type or catalyst-type curing agents. Examples of polyaddition-type curing agents include polyamine curing agents, acid anhydride curing agents, polyphenol curing agents, polythiols, and dicyandiamide. Examples of catalyst-type curing agents include tertiary amines, imidazoles, and Lewis acid complexes. These curing agents can be used alone or in combination of two or more.

[0101] When an epoxy resin is used, the resin composition may be a two-liquid curing type, that is, it may be cured by mixing a first liquid containing a main agent and a second liquid containing a curing agent.

[0102] When using a curing agent, the content of the curing agent is preferably 1 to 25 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 5 to 15 parts by mass, relative to 100 parts by mass of the epoxy resin. When the content of the curing agent is above the lower limit, the epoxy resin is more easily fully cured. Furthermore, when the content of the curing agent is below the upper limit, excess curing agent that does not participate in curing is less likely to be produced, resulting in an effect commensurate with the content of the curing agent.

[0103] <Acrylic resin>

[0104] As the acrylic resin used as the matrix resin, for example, a photocurable acrylic resin is used. As the acrylic resin, any component that constitutes an acrylic polymer by curing can be used, and various acrylic compounds such as (meth)acrylates such as (meth)acrylates and (meth)hydroxyalkyl (meth)acrylates, (meth)acrylic acid, (meth)acrylamides, and carbamate (meth)acrylates can be cited. In addition, vinyl monomers that can be copolymerized with the above-mentioned acrylic compounds can also be included. The acrylic resin preferably has an alkyl group on the side chain. In the case of obtaining an acrylic resin having an alkyl group on the side chain, the acrylic resin having an alkyl group on the side chain can be obtained by using methacrylate, methacrylic acid, (meth)alkyl acrylate, etc. in at least a part of the acrylic compound used as the matrix resin.

[0105] For the content (filling rate) of matrix resin in resin combination, be preferably more than 5 volume % and below 19.9 volume % relative to the cumulative volume of resin combination, more preferably more than 8 volume % and below 17 volume %, further preferably more than 10 volume % and below 15 volume %.When the content of matrix resin is above these lower limits, the inorganic filler being dispersed in the resin can be suitably dispersed and maintained in the matrix resin. In addition, by being set below these upper limits, a certain amount of inorganic filler, antioxidant can be coordinated in resin combination.

[0106] (Inorganic filler)

[0107] Examples of the inorganic filler include carbides, nitrides, oxides, hydroxides, and carbon-based materials.

[0108] Examples of carbides include silicon carbide, boron carbide, aluminum carbide, titanium carbide, and tungsten carbide. Examples of nitrides include silicon nitride, boron nitride, aluminum nitride, gallium nitride, chromium nitride, tungsten nitride, magnesium nitride, molybdenum nitride, and lithium nitride. Examples of oxides include aluminum oxides such as zinc oxide, iron oxide, alumina, and boehmite, magnesium oxide, titanium oxide, cerium oxide, and zirconium oxide, as well as silicon oxide (silicon dioxide). Examples of hydroxides include metal hydroxides such as aluminum hydroxide, calcium hydroxide, and magnesium hydroxide. Examples of carbon materials include diamond, carbon black, graphite, graphene, fullerene, carbon nanotubes, and carbon nanofibers. Examples of diamonds include nanodiamonds, primary diamonds, and crushed diamonds formed by crushing primary diamonds. In addition, inorganic fillers such as talc, which is a silicate mineral, may also be used. As boron nitride, cubic boron nitride is preferably used.

[0109] Preferred inorganic fillers include nitrides, metal oxides, and diamonds, with boron nitride, aluminum nitride, aluminum oxide, zinc oxide, and diamond being more preferred. Nitrides, metal oxides, and diamonds often use metals such as iron and manganese as catalysts during their synthesis. Consequently, metallic impurities often adhere to the surfaces of these inorganic fillers. However, the use of the aforementioned specific antioxidants can appropriately prevent oxidative degradation caused by these metallic impurities, thereby improving long-term reliability.

[0110] The inorganic filler is preferably a thermally conductive inorganic filler. From the perspective of improving thermal conductivity, the thermal conductivity of the inorganic filler is preferably 8W / (m·K) or more, more preferably 20W / (m·K) or more, and further preferably 30W / (m·K) or more. There is no particular limit to the upper limit of thermal conductivity, and for example, it is 2500W / (m·K). It should be noted that the thermal conductivity of the inorganic filler can be measured, for example, by measuring the cross section of the particles cut by a cross-section polisher using a thermal microscope manufactured by Betel Co., Ltd. by a periodic heating thermal reflection method.

[0111] As an inorganic filler, it is preferred that at least one selected from diamond and cubic boron nitride (hereinafter sometimes referred to as the "first filler") be included among the above-mentioned inorganic fillers. Diamond and cubic boron nitride have particularly excellent thermal conductivity among inorganic fillers, and by using these substances as inorganic fillers, the thermal conductivity of the resin composition can be easily improved. In addition, although relatively large amounts of metal impurities such as manganese are attached to the surfaces of diamond and cubic boron nitride, as described above, even if a large amount of metal impurities are attached to the surface, long-term reliability can be improved by using a specific antioxidant.

[0112] The filling rate of the first filler is preferably 20% by volume or more, more preferably 30% by volume or more, and further preferably 50% by volume or more, based on the total amount of the resin composition. It is preferably 80% by volume or less, more preferably 78% by volume or less, and further preferably 75% by volume or less.

[0113] The first filler is preferably an octahedron or a truncated octahedron. Octahedral and truncated octahedron fillers have a small aspect ratio and excellent sliding properties, making them easy to stack, which can easily improve thermal conductivity and heat dissipation. Octahedral and truncated octahedron fillers are also called so-called as-grown particles. Crystalline particles that retain their shape as synthesized without being crushed can be used.

[0114] It should be noted that the “octahedron” can be ideally exemplified by Figure 1 The regular octahedron shown in (A) does not refer to a strictly regular octahedron in the geometric sense, but refers to a shape that can be identified as a roughly regular octahedron when visually observed with a microscope or the like. In addition, a "truncated octahedron" is a polyhedron having a shape in which the vertices of an octahedron (ideally a regular octahedron) are cut off, and is also called a hexadecahedron. The "truncated octahedron" does not need to be Figure 1 The strict hexaoctahedron shown in (B) refers to a shape that can be recognized as a hexaoctahedron by those skilled in the art when visually observed with a microscope or the like.

[0115] It should be noted that octahedral diamond and truncated octahedral diamond can be easily produced by synthesis using a high temperature and high pressure method, and can also be made into relatively large particle sizes.

[0116] The first filler may have a shape other than an octahedron or a truncated octahedron, and may have an irregular shape, for example. Examples of irregular-shaped fillers include crushed fillers formed by crushing crystalline particles.

[0117] The first filler may be used alone or in combination of two or more.

[0118] From the perspective of thermal conductivity, the ratio of the combined volume of the octahedra and truncated octahedra in the first filler to the combined volume of the first filler is preferably 30% by volume or greater, more preferably 40% by volume or greater, and even more preferably 50% by volume or greater. The upper limit of the combined volume ratio of the octahedra and truncated octahedra is 100% by volume.

[0119] The inorganic filler may contain a filler (hereinafter also referred to as "the second filler") other than diamond particles and cubic boron nitride. In this case, the inorganic filler preferably also contains the second filler in addition to the first filler. For a specific example of the second filler, as listed as the variety used in the inorganic filler other than diamond and cubic boron nitride, among the above-mentioned varieties, it is preferably at least one of a metal oxide and a nitride, wherein, it is more preferably at least one of a boron nitride other than zinc oxide, aluminum oxide, aluminum nitride, and cubic boron nitride. The hardness of the above-mentioned nitride and metal oxide is relatively high, and the friction coefficient is also low, so the sliding property becomes high, and it is easy to improve fluidity. In addition, since the thermal conductivity is also high, it is easy to improve thermal conductivity.

[0120] The shape of the second filler is not particularly limited and can be any of a polyhedral shape, an irregular shape, a plate shape, a sphere shape, a needle shape, a fiber shape, a tube shape, etc. As a polyhedral shape, it can be the above-mentioned octahedron, a truncated octahedron, a cube, or a Figure 2 Polyhedral shapes other than the octahedron, truncated octahedron, and cube shown. Figure 2 Examples of polyhedral fillers include those having crystal faces such as a-plane {1120}, c-plane {0001}, h-plane {1123}, n-plane {2243}, and r-plane {1012}. Polyhedral fillers are also known as as-grown particles, and are crystalline particles that retain their original shape without breaking or otherwise disintegrating.

[0121] As the second filler, a polyhedral shape other than an octahedron and a truncated octahedron, a plate shape, an irregular shape, a spherical shape, or the like is preferable.

[0122] The second filler also preferably includes a so-called round filler. It should be noted that the round filler refers to a filler with a sphericity of 0.75 or more. In the above, for example, a filler with a multi-faceted shape can be a round filler. In addition, a spherical filler is also a type of round filler. The spherical filler can be a sphere, but is not limited to a sphere. In this specification, a filler with a sphericity of 0.95 or more is regarded as a spherical filler. It should be noted that the upper limit of the sphericity of spherical fillers and round fillers is 1.

[0123] In the present invention, when the volume ratio of the first filler is high, a portion of the first filler may not be filled. However, if the inorganic filler contains a so-called round filler as the second filler, the unfilled first filler is less likely to come into contact with the corners, and the fluidity is easily improved. In addition, the use of round fillers can easily increase the filling rate of the inorganic filler.

[0124] The round filler can be appropriately selected from the above-mentioned fillers and is preferably at least one of metal oxides and nitrides, more preferably aluminum oxide and aluminum nitride, and even more preferably aluminum oxide.

[0125] The round filler may be used alone or in combination of two or more.

[0126] The sphericity of each filler can be determined by examining an electron microscope photograph of each filler and calculating (diameter of a circle equal to the projected area of ​​the particle / diameter of the smallest circle circumscribing the projected image of the particle) from the obtained image.

[0127] In the resin composition, the filling rate of the round filler as the second filler relative to 100% by volume of the resin composition is preferably 3% by volume or more, more preferably 5% by volume or more, and even more preferably 8% by volume or more. Furthermore, in the resin composition, the round filler is preferably 90% by volume or less, more preferably 70% by volume or less, and even more preferably 40% by volume or less relative to 100% by volume of the inorganic filler.

[0128] In the resin composition, the filling rate of the second filler relative to 100 volume % of the resin composition is preferably 5 volume % or more, more preferably 8 volume % or more, and even more preferably 10 volume % or more. Furthermore, in the resin composition, the content of the spherical filler relative to 100 volume % of the inorganic filler is preferably 90 volume % or less, more preferably 75 volume % or less, and even more preferably 45 volume % or less.

[0129] The filling rate of the inorganic filler in the resin composition of the present invention is preferably 80 volume % or more, more preferably 83 volume % or more, and further preferably 85 volume % or more, based on the total amount of the resin composition. By making the content of the inorganic filler above the above lower limit, it is easy to improve the thermal conductivity of the resin composition. In addition, if the filling rate of the inorganic filler is improved, the matrix resin etc. are easily oxidized and degraded due to the influence of metal impurities attached to the surface of the inorganic filler. However, in the present invention, by using a specific antioxidant, it is possible to suppress oxidative degradation and improve long-term reliability.

[0130] In addition, from the perspective of containing a certain amount of resin and antioxidant and properly dispersing the inorganic filler in the matrix resin, the filling rate of the inorganic filler is preferably 90 volume % or less, more preferably 88 volume % or less, and even more preferably 87 volume % or less.

[0131] It should be noted that, in this manual, " filling rate " refers to the volume % relative to the cumulative volume of resin combination, for example, the filling rate of inorganic filler refers to the volume % shared by inorganic filler relative to the cumulative volume of resin combination. The cumulative volume of resin combination is the summation of the volume of all the components constituting resin combination. In addition, for example, the volume of inorganic filler is the summation of the volume of all the components (filler) constituting inorganic filler. The volume of each component can be calculated by the weight and density of each component.

[0132] It should be noted that the filling ratio (volume %) of above-mentioned inorganic filler can be obtained as described above, or can be for example to separate each component and obtain from resin combination. Specifically, first, in resin combination, suitably add solvent, resin or resin and antioxidant are dissolved, utilize centrifuge etc. that resin or resin and antioxidant are separated from inorganic filler.Then, measure the proportion and the weight of the mixture of isolated resin or resin and antioxidant, and obtain the volume of the mixture of resin or resin and antioxidant by this measured value. Similarly, for isolated inorganic filler, also measure proportion and weight, and obtain the volume of inorganic filler overall by this measured value. In addition, for isolated inorganic filler, can be separated by kind by known method, measure the proportion and weight of each inorganic filler, and obtain the volume of each inorganic filler by this measured value, calculate the volume % (filling ratio) of each inorganic filler.

[0133] The specific gravity of the separated resin and the like, and the specific gravity of the inorganic filler can be measured at 23° C. using a densitometer (for example, a measuring device “Aquapic II 1340”, manufactured by Shimadzu Corporation).

[0134] The average particle size of the primary particles of the inorganic filler included in the resin composition of the present invention is, for example, less than 400 μm, preferably less than 200 μm, more preferably less than 100 μm, and further preferably less than 70 μm. By making the average particle size of the primary particles of the inorganic filler below the above-mentioned upper limit, the filmization of the resin composition can be achieved, and the resin composition is easily filled even in narrow gaps such as inside electronic devices. From the perspective of ensuring the thermal conductivity of the resin composition, the average particle size of the primary particles of the inorganic filler is preferably more than 0.1 μm, more preferably more than 0.2 μm.

[0135] It should be noted that regarding the average particle size of the primary particles of the inorganic filler, the average particle size of the primary particles of the entire inorganic filler may be within the above range. When two or more inorganic fillers are used, it is preferred that all of the various inorganic fillers be within the above range. The same applies to the following.

[0136] The average particle size of the primary particles of the first filler is preferably 400 μm or less, more preferably 200 μm or less, and further preferably 150 μm or less. In addition, the average particle size of the primary particles of the second filler is preferably 200 μm or less, more preferably 100 μm or less, and further preferably 70 μm or less. By making the average particle size of the primary particles of the first filler and the second filler below the above-mentioned upper limit, the filmization of the resin composition can be achieved, and the resin composition can be easily filled even in narrow gaps such as inside electronic devices.

[0137] The average particle size of the primary particles of the first filler is preferably 10 μm or greater, more preferably 20 μm or greater. The average particle size of the primary particles of the second filler is preferably 0.1 μm or greater, more preferably 0.2 μm or greater. By setting the average particle size of the primary particles of the first and second fillers to be above the above lower limits, the thermal conductivity of the resin composition can be easily ensured.

[0138] The average particle size of the primary particles can be determined by measuring the 50% particle size (D50) in the cumulative particle size distribution of the primary particles on a volume basis. The cumulative particle size distribution on a volume basis is determined using a laser diffraction / scattering particle size distribution analyzer. Examples of laser diffraction / scattering particle size distribution analyzers include the "MT3300EXII" manufactured by Microtrac.

[0139] (Dispersant)

[0140] The resin composition of the present invention may contain a dispersant. By using a dispersant, the dispersibility of the inorganic filler is improved and the accumulation of the inorganic filler is promoted. As the dispersant, a silane coupling agent is preferably used.

[0141] As a silane coupling agent, for example, an alkoxysilane compound can be used. An alkoxysilane compound is a compound having a structure in which one to three of the four bonds carried by a silicon atom (Si) are bonded to an alkoxy group, and the remaining bonds are bonded to an organic substituent. The alkoxy group in an alkoxysilane compound is a hydrolyzable group, and examples thereof include methoxy, ethoxy, orthooxy, butoxy, pentyloxy, and hexyloxy. Among these, alkoxysilane compounds having a methoxy or ethoxy group are preferred.

[0142] From the perspective of improving affinity with inorganic fillers such as diamond, the number of alkoxy groups possessed by the alkoxysilane compound is preferably 3. Therefore, the alkoxysilane compound is more preferably at least one selected from trimethoxysilane compounds and triethoxysilane compounds.

[0143] Examples of the functional group contained in the organic substituent of the alkoxysilane compound include acryloyl, alkyl, carboxyl, vinyl, methacryloyl, aryl, amino, isocyanate, isocyanurate, epoxy, hydroxyl, and mercapto groups.

[0144] It should be noted that by appropriately selecting the functional group, compatibility with the resin becomes good. From this perspective, when the resin is an acrylic resin, the functional group is preferably an acryloyl group or a methacryloyl group. In addition, when the resin is an epoxy resin, the functional group is preferably an epoxy group.

[0145] In addition, from the perspective of easy fusion with resins such as silicone resins and improved dispersibility of inorganic fillers, the alkoxysilane compound is preferably an alkylalkoxysilane compound having an alkyl group bonded to a silicon atom. The number of carbon atoms in the alkyl group bonded to the silicon atom is preferably 4 or more. In addition, from the perspective of the low viscosity of the alkoxysilane compound itself and the low viscosity of the resin composition, the number of carbon atoms in the alkyl group bonded to the silicon atom is preferably 16 or less.

[0146] Preferred examples of the alkylalkoxysilane compound include n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane.

[0147] In addition, examples of alkoxysilane compounds other than alkylalkoxysilane compounds include 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, and 3-phenylaminopropyltrimethoxysilane.

[0148] As a silane coupling agent, an organosilicon compound having a polar group at the end can be used. Here, the polar group can bond to a Si atom. Therefore, the polar group is preferably a hydrolyzable silyl group such as a silanol group or an alkoxysilyl group, and more preferably an alkoxysilyl group. Organosilicon compounds having a polar group at the end are preferably used when the resin is an organosilicon resin.

[0149] The resin composition contains an organosilicon compound with a terminal polar group as a silane coupling agent. The polar groups of the silane coupling agent bond or interact with trace functional groups on the surface of inorganic fillers such as diamond, thereby improving the slip properties of the inorganic filler or facilitating dispersion of the inorganic filler in the resin. In particular, alkoxy groups are easily hydrolyzed and react with the diamond surface, while hydroxyl groups interact with polar groups on the surface of the inorganic filler and enter the inorganic filler interface, thereby enhancing slip properties.

[0150] Furthermore, by using an organosilicon compound as a silane coupling agent, when an organosilicon resin is used as a resin, the inorganic filler is particularly easily fused with the resin, and the filling rate of the inorganic filler in the resin composition is easily increased.

[0151] The organosilicon compound having a polar group at the end is preferably an organopolysiloxane having a hydrolyzable silyl group at the molecular chain end (hereinafter also referred to as organopolysiloxane (X)). The organopolysiloxane (X) may be linear, branched, or a mixture of linear and branched chains, but is preferably linear. Furthermore, the organopolysiloxane (X) is preferably an organopolysiloxane having at least one hydrolyzable silyl group at the molecular chain end, more preferably an organopolysiloxane having at least one hydrolyzable silyl group at only one terminal, and even more preferably an organopolysiloxane having three hydrolyzable silyl groups at one terminal. The hydrolyzable silyl group is more preferably an alkoxysilyl group, and even more preferably a methoxysilyl group.

[0152] The organopolysiloxane (X), having a hydrolyzable silyl group at its terminal end, readily reacts or interacts with functional groups present on the surface of the inorganic filler, thereby enhancing the lubricity of the inorganic filler. Furthermore, the presence of a polysiloxane structure also improves the dispersibility of the inorganic filler.

[0153] Specifically, the organopolysiloxane (X) is preferably a compound represented by the following formula (2).

[0154]

[0155] In formula (2), R 1 Each independently represents any one of an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. In formula (2), a plurality of R 1 Each may be the same or different. 2 Each independently represents an alkyl group having 1 to 4 carbon atoms. In formula (2), R 2 When there are multiple R 2 Each may be the same or different. 3 are each independently any one of an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group having 2 to 4 carbon atoms, a hydrogen atom, and an acyl group having 2 to 4 carbon atoms. In formula (2), R 3 When there are multiple R 3 Can be the same or different. 4 is an alkyl group having 1 to 8 carbon atoms. 6is an oxygen atom or a divalent organic group having 1 to 40 carbon atoms. m is an integer of 3 to 315. In formula (2), a is an integer of 0 to 2.

[0156] In the above formula (2), R 1 The alkyl group in the group may be a straight chain, a branched chain, or a cyclic structure. More specifically, examples include straight chain alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, and eicosyl; branched chain alkyl groups such as isopropyl, tert-butyl, isobutyl, 2-methylundecyl, and 1-hexylheptyl; and cyclic alkyl groups such as cyclopentyl, cyclohexyl, and cyclododecyl.

[0157] Examples of the haloalkyl group include chloromethyl, 3,3,3-trifluoropropyl, and 3-chloropropyl. Examples of the aryl group include phenyl, tolyl, and xylyl. Examples of the aralkyl group include benzyl, phenethyl, and 2-(2,4,6-trimethylphenyl)propyl.

[0158] Among them, R 1 It is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably a methyl group. 1 is methyl, more preferably 90% or more is methyl. 1 All are methyl groups.

[0159] In the above formula (2), R 2 is an alkyl group having 1 to 4 carbon atoms, R 2 When there are multiple R 2 Each of them can be the same or different. In addition, the alkyl group can be a straight chain or a branched chain. 2 It is preferably an alkyl group having 1 to 2 carbon atoms, and more preferably a methyl group. In addition, a is an integer of 0 to 2, and a is preferably 0 or 1, and more preferably 0.

[0160] In the above formula (2), R 3 is an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group having 2 to 4 carbon atoms, a hydrogen atom, or an acyl group having 2 to 4 carbon atoms, and R 3 When multiple R 3 They can be the same or different. 3 The alkyl, alkoxyalkyl and acyl groups in R can be straight chains or branched chains. 3 An alkyl group having 1 to 4 carbon atoms is preferred, and a methyl group is more preferred.

[0161] In the above formula (2), R 4 It is an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 2 to 6 carbon atoms, and more preferably a butyl group.

[0162] In the above formula (2), R 6 The group represented by the following formula (3), an oxygen atom, or a divalent hydrocarbon group having 1 to 20 carbon atoms is preferred, and the group represented by the following formula (3) or a divalent hydrocarbon group having 1 to 20 carbon atoms is more preferred. Here, the divalent hydrocarbon group having 1 to 20 carbon atoms is preferably an alkylene group, which may be a linear or branched chain. The divalent hydrocarbon group having 1 to 20 carbon atoms is preferably an alkylene group having 2 to 10 carbon atoms, more preferably an alkylene group having 2 to 8 carbon atoms, and even more preferably an alkylene group having 2 to 4 carbon atoms. Examples thereof include methylene, ethylene, propylene, butylene, and methylethylene, and ethylene is preferred.

[0163]

[0164] In formula (3), R 5 is a divalent hydrocarbon group having 1 to 20 carbon atoms, and multiple R 5 They can be the same or different. * is the same as R 1 -Si-R 1 The bonding position of the silicon atom in the 2 a(OR 3 ) 3-a The position where the silicon atoms in the bond.

[0165] R 5 The divalent hydrocarbon group in R is preferably an alkylene group, which may be a straight chain or a branched chain. 5 It is preferably an alkylene group having 2 to 10 carbon atoms, more preferably an alkylene group having 2 to 8 carbon atoms, further preferably an alkylene group having 2 to 4 carbon atoms, and more preferably an alkylene group represented by CH2-CH2-CH2- or -CH(CH3)-CH2-.

[0166] In formula (2), m represents the number of repetitions, and is an integer of 3 to 315, preferably an integer of 4 to 280, more preferably an integer of 5 to 220, and even more preferably an integer of 5 to 100.

[0167] As the dispersant, dispersants other than silane coupling agents can also be used, and polymer dispersants other than organosilicon compounds can be used. As the polymer dispersant used, polymer compounds with functional groups can be enumerated. As the polymer compound, for example, acrylic acid, vinyl, polyester, polyurethane, polyether, epoxy, polystyrene, amino etc. can be enumerated. In addition, as the functional group, carboxyl, phosphoric acid, sulfonic acid, carboxylate, phosphate, sulfonate, hydroxyl, amino, quaternary ammonium salt, amide etc. can be enumerated, preferably phosphate.

[0168] A polymeric dispersant other than an organosilicon compound is preferably used when the matrix resin contains a resin other than an organosilicon resin, such as an epoxy resin or an acrylic resin.

[0169] The functional groups of the polymeric dispersant bond or interact with trace functional groups on the surface of diamond or other inorganic fillers, thereby improving the lubricity of the inorganic filler or facilitating its dispersion in the matrix resin. Furthermore, since the polymeric dispersant is a polymer other than an organosilicon compound, when a resin component other than an organosilicon resin (e.g., an epoxy resin or an acrylic resin) is used as the matrix resin, the inorganic filler is particularly easily incorporated into the matrix resin, thereby increasing the filling rate of the inorganic filler in the resin composition.

[0170] As the dispersant, one of the above-mentioned substances may be used alone, or two or more thereof may be used in combination.

[0171] Relative to the total mass reference 100 mass % of resinous components, the content of the dispersant in the resin combination is, for example, more than 1 mass % and less than 70 mass %. The above-mentioned content of the dispersant in the resin combination is preferably more than 3 mass % and less than 40 mass %, more preferably more than 5 mass % and less than 30 mass %. By setting the content of the dispersant to more than a certain value, the dispersion of the inorganic filler can be promoted by the dispersant, fully promoting the filling of the inorganic filler. In addition, by setting the amount of the dispersant to less than a certain value, the crushing effect of the inorganic filler can be brought into play, and it is not easy to occur that the material reaggregation of the dispersed independent particles is undesirable. Therefore, by setting the content of the dispersant in the above-mentioned desired range, it is easy to improve thermal conductivity.

[0172] (Other additives)

[0173] When the resin composition is a curing type, a curing catalyst may be appropriately included. For example, when using an addition reaction curing type silicone resin, platinum catalysts, palladium catalysts, rhodium catalysts, etc. can be cited as the curing catalyst. These curing catalysts are catalysts used to cure the silicone resin as the main agent and the silicone resin as the curing agent. The amount of the curing catalyst is generally 0.1 to 200 ppm, preferably 0.5 to 100 ppm, relative to the silicone resin on a mass basis. In the case of a two-liquid curing type, the curing catalyst is preferably added to the first liquid containing the main agent, but may also be included in the second liquid containing the curing agent.

[0174] The resin composition of the present invention may contain, as needed, antioxidants other than the above-mentioned specific antioxidants, colorants, flame retardants, antistatic agents, and other additives commonly used in heat dissipation components. Furthermore, when using a curable resin such as a thermosetting resin, the resin composition may contain a reaction inhibitor. By including a reaction inhibitor, the catalytic activity of the curing catalyst may be suppressed, thereby extending the shelf life and pot life of the resin composition. Furthermore, when using a photocurable resin, the resin composition may contain a photopolymerization initiator.

[0175] (Physical Properties of Resin Composition)

[0176] The resin composition of the present invention, by including an inorganic filler, has a higher thermal conductivity, resulting in improved thermal conductivity. The thermal conductivity of the resin composition is preferably 5 W / (m·K) or higher, more preferably 10 W / (m·K) or higher. The higher the thermal conductivity of the resin composition, the better the heat dissipation properties. However, for practical purposes, it can be, for example, 25 W / (m·K) or lower.

[0177] In addition, the resin composition of the present invention can improve long-term reliability in high-temperature environments by suppressing the weight loss rate and the hardness increase rate. The weight loss rate of the resin composition is preferably less than 1%, more preferably less than 0.7%, and even more preferably less than 0.5%. In addition, the hardness increase rate of the resin composition is preferably less than 30%, more preferably less than 20%, and even more preferably less than 10%. The lower the weight loss rate, the more it can improve long-term reliability, and a rate of 0% or more can be sufficient. In addition, the lower the hardness increase rate, the more it can improve long-term reliability, and a rate of 0% or more can be sufficient.

[0178] The weight reduction rate and the hardness increase rate can be measured by the methods described in the Examples.

[0179] (Preparation of resin composition)

[0180] The resin composition of the present invention can be prepared by mixing a base resin, an antioxidant, an inorganic filler, and, if necessary, additives such as a dispersant. The method for mixing these components is not particularly limited. For example, the composition can be prepared by adding an antioxidant, an inorganic filler, and, if necessary, an additive such as a dispersant, to the base resin, followed by stirring or kneading.

[0181] In the case of a two-liquid curing type, a first liquid and a second liquid produced by the same method as described above may be prepared, and the first liquid and the second liquid may be mixed to produce a resin composition.

[0182] Alternatively, the inorganic filler can be surface-treated with a dispersant before being mixed with the resin and antioxidant. By pre-treating the inorganic filler's surface with a dispersant, the surface of the filler has been modified with the dispersant. The pre-modified inorganic filler can then be mixed with the matrix resin and antioxidant to prepare a resin composition.

[0183] The method for pre-treating the surface with a dispersant is not particularly limited and may be performed by a known method, such as a wet treatment method or a dry treatment method. In the wet treatment method, for example, an inorganic filler may be added to a treatment solution obtained by dispersing or dissolving the dispersant in a solvent, and the mixture may be mixed. The mixture may then be dried, heated, washed, etc., to allow the dispersant to bind or adhere to the surface of the inorganic filler.

[0184] The dry treatment method is a method of performing surface treatment without using a solvent. Specifically, a dispersant is mixed with an inorganic filler, stirred with a mixer or the like, and then heated to allow the dispersant to bind or adhere to the surface of the inorganic filler.

[0185] [Heat dissipation components]

[0186] The heat dissipation component of the present invention is formed by the above-mentioned resin composition. For example, when the resin component contains a curable resin, the heat dissipation component can be obtained by forming the above-mentioned resin composition into a prescribed shape and then curing it by appropriate heating or the like. In addition, when a photocurable resin is used, the resin composition can be formed into a prescribed shape and then cured by irradiating it with light such as ultraviolet rays. In addition, except for the case where the resin component contains a curable resin, the heat dissipation component can be made by forming the resin composition into a prescribed shape or an irregular shape. There is no particular limitation on the method for forming the resin composition into a prescribed shape, etc., and the resin composition can be formed into a film, sheet, block, etc. by coating, casting, potting, extrusion molding, etc., or into an irregular shape, etc. For coating, a dispenser can be used, for example. The resin composition of the present invention has good fluidity, so it can be easily coated, cast, potted, extruded, etc., and the sprayability from the dispenser is also good.

[0187] The heat dissipation component of the present invention is used, for example, in electronic devices. That is, the present invention also provides an electronic device having a heat dissipation component. The heat dissipation component of the present invention has a high thermal conductivity, so if used inside an electronic device, high heat dissipation can be ensured. More specifically, the heat dissipation component is arranged on the electronic component to dissipate the heat generated by the electronic component. In addition, the heat dissipation component of the present invention is preferably configured and used in a manner of filling the gap between two opposing components. For example, one of the two opposing components can be an electronic component, and the other can be any one of a radiator for dissipating heat from the electronic component, a housing of an electronic device, a substrate, etc.

[0188] Example

[0189] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0190] The methods for measuring and evaluating the physical properties of the present invention are as follows. Among the physical properties, the results of measuring the average particle size of the primary particles are shown in Table 4. Additionally, the results of measuring and evaluating the weight loss rate, hardness increase rate, storage stability, and thermal conductivity are shown in Tables 6, 8, 10, 12, 14, and 16.

[0191] [Average particle size of primary particles]

[0192] The average particle size of the primary particles of each inorganic filler was determined by measuring the 50% particle size (D50) in the cumulative particle size distribution on a volume basis by the method described in the manual.

[0193] [Weight reduction rate]

[0194] The weight reduction rate when 10 g of the resin sheet produced in each Example and Comparative Example was heated in an oven at 150° C. for 1000 hours was calculated by the following mathematical formula.

[0195] Weight reduction rate (%)=(1-(weight of the resin composition after heating / initial weight of the resin composition))×100 On this basis, the weight reduction rate of the resin sheet was evaluated based on the following evaluation criteria.

[0196] (Evaluation Criteria)

[0197] A: Weight reduction rate is less than 0.5%

[0198] B: Weight reduction rate is more than 0.5% and less than 1%

[0199] C: Weight reduction rate exceeds 1%

[0200] [Hardness increase rate]

[0201] Liquid A and Liquid B prepared in each Example and Comparative Example were mixed at a weight ratio of 1 / 1. This mixture was heated at 80°C for 30 minutes to cure, and the hardness increase rate of the cured product was measured under the following conditions. However, in Examples 49 and 50, the resulting resin compositions were cured under the conditions shown in each Example, and the hardness increase rate of the resulting cured products was measured under the following conditions. Furthermore, in Examples 48 and 50, samples were formed from the resulting resin compositions, and the hardness increase rate was measured under the following conditions.

[0202] Environment: Thermostat (PHH-101, made by Espec) 150°C / 1000 hours

[0203] Sample size: 50mm×25mm×6mm

[0204] ·Measurement method: E-type hardness based on JIS K 6253-3

[0205] Evaluation method: Hardness increase rate = ((hardness after heat resistance test - initial hardness) / initial hardness) × 100

[0206] On this basis, the hardness increase rate of the cured product of the resin composition was evaluated based on the following evaluation criteria.

[0207] A: Hardness increase rate is less than 10%

[0208] B: Hardness increase rate is 10% or more and less than 30%

[0209] C: Hardness increase rate is more than 30%

[0210] [Storage stability]

[0211] Liquid A (first liquid) and liquid B (second liquid) prepared in each example and comparative example were filled into respective syringes. Each liquid was heated in an oven at 50°C for 1000 hours and then returned to room temperature. Liquid A and liquid B were mixed in a weight ratio of 1 / 1, and the viscosity was measured after standing at room temperature for 10 minutes.

[0212] In addition, separate syringes filled with liquid A and liquid B were prepared separately. Liquid A and liquid B were mixed at a weight ratio of 1 / 1 without heating, and the viscosity was measured after standing at room temperature for 10 minutes.

[0213] Then, the viscosity ratio (viscosity of the mixture prepared by mixing after heating / viscosity of the mixture prepared by mixing without heating) was calculated, and storage stability was evaluated based on the following evaluation criteria.

[0214] (Evaluation Criteria)

[0215] A: Curable

[0216] B: Cannot be cured

[0217] (Evaluation method)

[0218] A viscosity ratio (viscosity of the mixture prepared by mixing after heating / viscosity of the mixture prepared by mixing without heating) of 0.8 or greater was considered curable. Viscosity was evaluated using a Brookfield rotational viscometer with a No. 14 rotor at a rotational speed of 5 rpm and a measurement temperature of 25°C.

[0219] [Thermal conductivity]

[0220] The resin sheets obtained in each example and comparative example were used as test samples. The thermal resistance of the samples was measured at room temperature (25°C) using a "DynTIM" device manufactured by Mentor Graphics in accordance with ASTM D5470. The thermal conductivity was calculated from this thermal resistance. The thermal resistance was measured with the sample thickness set to 500 μm, 1000 μm, and 1500 μm.

[0221] On this basis, the thermal conductivity of the resin sheet was evaluated based on the following evaluation criteria.

[0222] (Evaluation Criteria)

[0223] A: 10W / (m·K) or more

[0224] B: 5W / (m·K) or more and less than 10W / (m·K)

[0225] C: less than 5W / (m·K)

[0226] The silane coupling agent, antioxidant, and inorganic filler used in Examples and Comparative Examples are as follows.

[0227] (Silane coupling agent)

[0228] Decyltrimethoxysilane (product name: KBM3103, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0229] (Antioxidant)

[0230] Hindered phenol antioxidant 1 (product name: ADEKA STABU AO-20, manufactured by ADEKA Corporation)

[0231] Hindered phenol antioxidant 2 (product name: ADEKA STABU AO-30, manufactured by ADEKA Corporation)

[0232] Hindered phenol antioxidant 3 (product name: ADEKA TABU AO-40, manufactured by ADEKA Corporation)

[0233] Hindered phenol antioxidant 4 (product name: ADEKA STABU AO-50, manufactured by ADEKA Corporation)

[0234] Hindered phenol antioxidant 5 (product name: ADEKA STABU AO-60, manufactured by ADEKA Corporation)

[0235] Hindered phenol antioxidant 6 (product name: ADEKA STABU AO-80, manufactured by ADEKA Corporation)

[0236] Hindered phenol antioxidant 7 (product name: ADEKA STABU AO-330, manufactured by ADEKA Corporation)

[0237] Hindered phenol antioxidant 8 (product name: SEENOX 224M, manufactured by Dipro Chemicals Co., Ltd.)

[0238] Hindered phenol antioxidant 9 (product name: ADEKA START CDA-10, manufactured by ADEKA Corporation)

[0239] Hindered phenol antioxidant 10 (product name: Irganox 565, manufactured by BASF)

[0240] Organic chelate antioxidant 1 (product name: ADEKA STABU CDA-1, manufactured by ADEKA Corporation)

[0241] Organic chelate antioxidant 2 (product name: ADEKA STABU ZS-27, manufactured by ADEKA Corporation)

[0242] Organic chelate antioxidant 3 (product name: EDTA, manufactured by TCI)

[0243] Organic chelate antioxidant 4 (product name: phthalocyanine, manufactured by TCI)

[0244] Hydrazide antioxidant 1 (product name: Adekastat CDA-6S, manufactured by ADEKA Corporation)

[0245] Hydrazide antioxidant 2 (hydrazide derivative, product name: ADEKA STABU ZS-90, manufactured by ADEKA Corporation)

[0246] Hydrazide antioxidant 3 (hydrazide derivative, product name: ADEKA STABU ZS-91, manufactured by ADEKA Corporation)

[0247] Phosphorus antioxidant 1 (product name: ADEKA STABU PEP-36, manufactured by ADEKA Corporation)

[0248] Phosphorus antioxidant 2 (product name: ADEKA STABU HP-10, manufactured by ADEKA Corporation)

[0249] Phosphorus antioxidant 3 (product name: ADEKA STABU 2112, manufactured by ADEKA Corporation)

[0250] Sulfur antioxidant 1 (product name: ADEKA TABU AO-412S, manufactured by ADEKA Corporation)

[0251] Sulfur antioxidant 2 (product name: SEENOX BCS, manufactured by Dipro Chemicals Co., Ltd.)

[0252] Sulfur antioxidant 3 (product name: SEENOX DS, manufactured by Dipro Chemicals Co., Ltd.)

[0253] Sulfur antioxidant 4 (product name: SEENOX DM, manufactured by Dipro Chemicals Co., Ltd.)

[0254] Sulfur antioxidant 5 (product name: SEENOX DL, manufactured by Dipro Chemicals Co., Ltd.)

[0255] The detailed information of each antioxidant is shown in Tables 1 to 3.

[0256] Table 1

[0257]

[0258] Table 2

[0259]

[0260] Table 3

[0261]

[0262] (Inorganic filler)

[0263] Diamond 1 (manufactured by Tomei Daiya Co., Ltd.)

[0264] Diamond 2 (manufactured by Tomeidaiya Co., Ltd., crushed filler)

[0265] Cubic boron nitride (manufactured by Toto Corporation)

[0266] Alumina 1 (manufactured by Sumitomo Chemical Co., Ltd.)

[0267] Alumina 2 (manufactured by DIC Corporation)

[0268] Alumina 3 (manufactured by Adomatex Corporation)

[0269] Alumina 4 (manufactured by DENKA Corporation)

[0270] Aluminum nitride (manufactured by Showa Denko K.K.)

[0271] Magnesium oxide (manufactured by Sakai Chemical Co., Ltd.)

[0272] Boron nitride (manufactured by Momentive)

[0273] Zinc oxide (manufactured by Sakai Chemical Co., Ltd.)

[0274] The detailed information of each inorganic filler is shown in Table 4.

[0275] Table 4

[0276] type D50(μm) Manufacturer shape Diamond 1 54 Bu ーメイダヤ truncated octahedron Diamond 2 25 Bu ーメイダヤ irregular shape Cubic Boron Nitride 54 Bu ーメイダヤ truncated octahedron Alumina 1 3 Sumitomo Chemical round Alumina 2 35 DIC 14-sided polygon (circle) Alumina 3 0.25 アドマテツクス spherical Alumina 4 50 DENKA spherical Aluminum nitride 50 Showa Denko spherical MgO 50 Sakai Chemical Irregular shape (broken BN 45 Momentive Plate-like (scaly) ZnO 10 Sakai Chemical Irregular shape (broken)

[0277] [Example 1]

[0278] As a resin, 13.986 parts by volume of an organopolysiloxane (viscosity of 100 mPa·s at 25°C) having vinyl groups at both ends, which constitutes the main component of an addition reaction-type silicone resin, were added. An antioxidant and an inorganic filler were added according to the formulation shown in Table 5, and a catalytic amount of a platinum catalyst was further added to prepare a resin composition liquid A.

[0279] In addition, with respect to 13.986 parts by volume of the organohydrogen polysiloxane (viscosity of 100 mPa·s at 25°C) constituting the curing agent of the addition reaction type silicone resin, an antioxidant and an inorganic filler were added according to the formula shown in Table 5 to prepare a resin composition B liquid. Liquid A and liquid B were mixed in a mass ratio (liquid A / liquid B) of 1:1 to prepare a resin composition, which was injected into a molding mold and left at room temperature (25°C) for 4 hours to cure the resin composition to obtain a resin sheet. The resin sheet was used as a measurement sample to measure the weight loss rate, hardness increase rate, and thermal conductivity. In addition, the storage stability of the resin composition immediately after the mixture of liquid A and liquid B was evaluated.

[0280] [Examples 2 to 47, Comparative Examples 1 to 22, Reference Examples 1 and 2]

[0281] The same procedures as in Example 1 were carried out except that the components and amounts used were changed as shown in Tables 5, 7, 9, 11, 13, and 15. In Example 47, the storage stability was not evaluated.

[0282] [Example 48]

[0283] To 13.986 parts by volume of dimethyl silicone oil (KF96-100cs manufactured by Shin-Etsu Chemical), an antioxidant and an inorganic filler were added and mixed according to the formulation shown in Table 11 to prepare a resin composition. The resulting resin composition was used as a measurement sample, and the weight loss rate and thermal conductivity were measured.

[0284] [Example 49]

[0285] A resin mixture was prepared by adding 10 parts by mass of dicyandiamide (manufactured by Tokyo Chemical Industry Co., Ltd.) as a thermosetting agent and 1 part by mass of an imidazole curing agent (manufactured by Shikoku Chemical Industry Co., Ltd.) to 100 parts by mass of an epoxy resin (trade name "Epicoat 828US", manufactured by Mitsubishi Chemical Corporation). An antioxidant and an inorganic filler were added and mixed according to the formulation shown in Table 11 to 13.986 parts by volume of this resin mixture (base resin) to prepare a resin composition. The resulting resin composition was injected into a molding die and heated at 180°C for 2 hours to cure the resin composition, thereby producing a resin sheet. The resin sheet was used as a measurement sample, and the weight loss rate, hardness increase rate, and thermal conductivity were measured.

[0286] [Example 50]

[0287] An antioxidant and an inorganic filler were added to 13.986 parts by volume of an olefin resin (Sumitomo Chemical's Sumikase F723-P) according to the formulation shown in Table 11 and mixed to prepare a resin composition. The resulting resin composition was heated to 130°C, injected into a mold, and cured to produce a resin sheet. The resin sheet was used as a measurement sample, and the weight loss rate, hardness increase rate, and thermal conductivity were measured.

[0288] [Example 51]

[0289] 100 parts by mass of acrylic resin (4-hydroxybutyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.) and 5 parts by mass of acrylic resin (CN9005, manufactured by ARKEMA Co., Ltd.) were mixed. 1 part by volume of photopolymerization initiator (Irgacure OXE01, manufactured by BASF Co., Ltd.) was added to 12.986 parts by volume of the resulting mixture (resin). An antioxidant and an inorganic filler were further added and mixed according to the formula shown in Table 11 to prepare a resin composition. The resulting resin composition was injected into a molding die and subjected to UV light at 365 nm and 20 mW / cm 2 The resin sheet was cured by irradiation for 60 seconds and used as a measurement sample to measure the weight loss rate, hardness increase rate and thermal conductivity.

[0290] [Example 52]

[0291] As a resin, 0.986 parts by volume of a silane coupling agent was added to 13 parts by volume of an organopolysiloxane (viscosity of 100 mPa·s at 25°C) with vinyl groups at both ends constituting the main component of an addition reaction-type silicone resin, and mixed to produce a mixed composition. Diamond and alumina were added to the resulting mixed composition according to the formulation shown in Table 11, and a catalytic amount of a platinum catalyst was further added to prepare a resin composition, Liquid A.

[0292] In addition, 0.986 parts by volume of a dispersant were added to 13 parts by volume of an organohydrogen polysiloxane (viscosity of 100 mPa·s at 25°C) constituting a curing agent for an addition reaction-type silicone resin, and mixed to obtain a mixed composition. Diamond and alumina were added to the obtained mixed composition according to the formula shown in Table 1 to prepare a liquid B of the resin composition. Liquid A and liquid B were mixed in a mass ratio (liquid A / liquid B) of 1:1 to prepare a resin composition, which was injected into a molding mold and allowed to stand at room temperature (25°C) for 4 hours to cure the resin composition to obtain a resin sheet. The resin sheet was used as a measurement sample to measure the weight loss rate, hardness increase rate, and thermal conductivity. In addition, the storage stability of the resin composition immediately after the liquid A and liquid B were mixed was evaluated.

[0293] Table 5

[0294]

[0295] Table 6

[0296]

[0297] Table 7

[0298]

[0299] Table 8

[0300]

[0301] Table 9

[0302]

[0303] Table 10

[0304]

[0305] Table 11

[0306]

[0307] Table 12

[0308]

[0309] Table 13

[0310]

[0311] Table 14

[0312]

[0313] Table 15

[0314]

[0315] * In Tables 5, 7, 9, 11, 13, and 15, Silicone 1 represents an organopolysiloxane with vinyl groups at both ends constituting the main component of an addition-reaction-type silicone resin, or an organohydrogenpolysiloxane constituting the curing agent for the silicone resin. In this table, Silicone 2 represents dimethyl silicone oil.

[0316] Table 16

[0317]

[0318] The resin compositions of the above examples, by containing a specific antioxidant, exhibited favorable weight loss, hardness increase, and storage stability evaluation results, improving long-term reliability in high-temperature environments. Furthermore, the compositions exhibited excellent thermal conductivity.

[0319] In contrast, the resin compositions prepared in the comparative examples did not contain the specific antioxidant, and therefore at least the evaluation results of the weight reduction rate and the hardness increase rate were poor, resulting in failure to improve the long-term reliability in a high-temperature environment.

[0320] Furthermore, the resin composition prepared in Reference Example 1 did not contain an inorganic filler, and thus failed to achieve excellent thermal conductivity. Furthermore, the resin composition prepared in Reference Example 2 did not contain an antioxidant at all, resulting in poor evaluation results for weight loss and hardness increase, and thus failing to improve long-term reliability in high-temperature environments.

Claims

1. A resin composition comprising a base resin, an inorganic filler and an antioxidant, wherein the antioxidant is any one of a hydrazide antioxidant or a combination of a hindered phenol antioxidant and a chelate antioxidant. 2 . The resin composition according to claim 1 , wherein the chelate antioxidant is a hydrazide antioxidant. The resin composition according to claim 1 or 2, wherein the base resin has an alkyl group on a side chain of the molecule. The resin composition according to claim 1 or 2, wherein the inorganic filler comprises at least one selected from the group consisting of diamond and cubic boron nitride. The resin composition according to claim 1 or 2, wherein the base resin is at least one selected from silicone resin, epoxy resin and acrylic resin. A heat dissipation component formed from the resin composition according to claim 1 or 2. 7 . An electronic device comprising an electronic component and the heat dissipation member according to claim 6 provided on the electronic component.

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