Heat-resistant resin composition, heat-resistant resin sheet using same, and method for producing same

Abstract

To provide a heat-resistant resin composition which does not cause curing inhibition of a thermosetting resin and does not adversely affect semiconductors or the like, a heat-resistant resin sheet using the same, and a method for producing the same. The heat-resistant resin composition contains a heat resistance aid and a matrix resin comprising a thermosetting resin, and the heat resistance aid is a cellulose charcoal powder.

Description

Heat-resistant resin composition, heat-resistant resin sheet using the same, and method for producing the same

[0001] The present invention relates to a heat-resistant resin composition suitable for being interposed between a heat-generating portion of an electric or electronic part or the like and a heat radiator, a heat-resistant resin sheet using the same, and a method for producing the same.

[0002] In recent years, the performance of semiconductors such as CPUs has improved dramatically, resulting in enormous increases in heat generation. Therefore, heat sinks are attached to heat-generating electronic components, and thermally conductive sheets are used to improve adhesion between the semiconductor and the heat sink. While heat resistance is required for thermally conductive sheets as devices become smaller, perform better, and become more highly integrated, there is also a need to add pigments to differentiate products from those of other companies or between products. WO 2019-021826 proposes adding iron oxide or the like to a silicone composition to improve heat resistance. In JP 2018-123200 A, the applicant proposed carbon powders such as acetylene black, carbon nanotubes, carbon nanofibers, graphene, and furnace black as heat resistance improvers.

[0003] The present invention relates to a heat-resistant resin composition containing a matrix resin made of a thermosetting resin and a heat-resistant aid, wherein the heat-resistant aid is cellulose charcoal powder.

[0004] FIG. 1 is a schematic cross-sectional view showing a method for using a heat-resistant resin sheet according to one embodiment of the present invention. FIGS. 2A-B are schematic explanatory diagrams showing a method for measuring the thermal conductivity of a sample according to one embodiment of the present invention. FIG. 3 is a magnified SEM photograph (1000x magnification) of the bamboo charcoal powder used in one embodiment of the present invention. FIG. 4 is a graph showing the change in ASKER-C hardness over time when heat-resistant resin sheets according to an embodiment of the present invention and a comparative example were stored in a constant temperature bath at 150°C for up to 1000 hours. FIG. 5 is a graph showing the change in viscosity over time of heat-resistant resin compositions according to an embodiment of the present invention and a comparative example. Detailed Description of the Invention

[0005] However, conventional resin compositions and pigments added to resin sheets using the same often contain metals or ionic components such as sulfur, copper, cobalt, etc. The inclusion of these metals or ionic components can inhibit the curing of thermosetting resins, and resin sheets containing such metals or components also have the problem of adversely affecting semiconductors and the like.

[0006] In order to solve the above-mentioned conventional problems, the present invention provides a heat-resistant resin composition that does not inhibit the curing of thermosetting resins and does not adversely affect semiconductors, etc., a heat-resistant resin sheet using the same, and a method for producing the same.

[0007] The heat-resistant resin composition of the present invention is a heat-resistant resin composition containing a matrix resin made of a thermosetting resin and a heat-resistant auxiliary, and is characterized in that the heat-resistant auxiliary is cellulose charcoal powder.

[0008] The heat-resistant resin sheet of the present invention is characterized by comprising the heat-resistant resin composition described above and being formed into a sheet.

[0009] The method for producing a heat-resistant resin sheet of the present invention is characterized by comprising the steps of vacuum degassing the heat-resistant resin composition, rolling it, forming it into a sheet, and then heat-curing it to obtain a heat-resistant resin sheet.

[0010] The heat-resistant resin composition of the present invention contains a matrix resin made of a thermosetting resin and a heat-resistant auxiliary, and the heat-resistant auxiliary is cellulose charcoal powder, which does not inhibit the curing of the thermosetting resin or adversely affect semiconductors or the like. This provides a heat-resistant resin composition and a heat-resistant resin sheet using the same, as well as a method for producing the same. The cellulose charcoal powder is produced by burning natural cellulose at high temperatures to produce charcoal, which is then pulverized. Therefore, the heat-resistant resin composition containing the cellulose charcoal powder contains almost no metal or ionic components such as sulfur, copper, or cobalt. Therefore, even when exposed to temperatures of, for example, 150°C for long periods of time, the hardness of the heat-resistant resin composition is resistant to change. Such heat-resistant resin compositions are useful as thermally conductive compositions and thermally conductive sheets using the same, particularly as thermal interface materials (TIMs) containing thermally conductive particles. High heat resistance is important for heat-dissipating sheets, as they conduct heat from heat-generating electronic components such as semiconductors to heat sinks.

[0011] [Heat-Resistant Resin Composition] The heat-resistant resin composition of the present invention contains a matrix resin made of a thermosetting resin and a heat-resistant auxiliary as described above. <Matrix Resin (Component A)> The matrix resin made of a thermosetting resin of the present invention is, for example, a silicone resin, an acrylic resin, a fluororubber, an epoxy resin, a phenolic resin, an unsaturated polyester resin, a melamine resin, an acrylic resin, a fluororesin, or a non-reactive silicone oil. Among these, silicone resins and non-reactive silicone oils are preferred as the matrix resin because they have high heat resistance, are not corrosive to the surrounding area, and emit few by-products outside the system. The silicone resin may be in the form of rubber, gel, grease, putty, liquid, or the like.

[0012] Silicone resins will be described as matrix resins. Examples of silicone resins include addition-curable silicone resins, peroxide-curable silicone resins, and condensation-curable silicone resins. These may be used alone or in combination. Each silicone resin will be described.

[0013] As an example, the matrix resin preferably contains the following components (A1) and (A2): (A1) base polymer: an organopolysiloxane containing two or more alkenyl groups bonded to silicon atoms in one molecule; and (A2) crosslinking component: an organohydrogenpolysiloxane containing at least two hydrogen atoms bonded to silicon atoms in one molecule.

[0014] The addition-curable silicone resin may contain an organopolysiloxane that does not have a reactive group other than the components (A1) and (A2), such as an unreacted silicone oil, such as dimethylpolysiloxane.

[0015] Each component is described below. <<Base Polymer (Component A1)>> The base polymer is an organopolysiloxane containing two or more silicon-bonded alkenyl groups per molecule. This organopolysiloxane is the main component (base polymer component) in the matrix resin of the present invention. This organopolysiloxane contains two silicon-bonded alkenyl groups per molecule, such as vinyl or allyl groups, each having 2 to 8 carbon atoms, and particularly 2 to 6 carbon atoms. From the standpoint of workability, curability, and the like, it is desirable for the viscosity of the organopolysiloxane to be 10 to 1,000,000 mPa·s, and particularly 100 to 100,000 mPa·s, at 25°C.

[0016] Specifically, an organopolysiloxane represented by the following general formula (I) containing alkenyl groups bonded to silicon atoms at both ends of the molecular chain per molecule can be used. This organopolysiloxane is a linear organopolysiloxane whose side chains are blocked with alkyl groups. From the viewpoint of workability, curability, and the like, it is desirable for the organopolysiloxane to have a viscosity of 10 to 1,000,000 mPa·s at 25°C. Note that this linear organopolysiloxane may also contain a small amount of branched structures (trifunctional siloxane units) in the molecular chain.

[0017]

[0018] In the formula, each R 1may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups that do not have an aliphatic unsaturated bond, R 2 is an alkenyl group, and k is 0 or a positive integer.

[0019] In general formula (I), R 1 The unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond is preferably one having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. Specific examples of the unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl. Examples of the substituted monovalent hydrocarbon group having no aliphatic unsaturated bond include groups in which some or all of the hydrogen atoms of the unsubstituted monovalent hydrocarbon group have been substituted with halogen atoms such as fluorine, bromine, or chlorine; or with cyano groups, such as halogen-substituted alkyl groups such as chloromethyl, chloropropyl, bromoethyl, and trifluoropropyl; and cyanoethyl.

[0020] In general formula (I), R 2 The alkenyl group preferably has, for example, 2 to 6 carbon atoms, particularly 2 to 3. Specific examples of the alkenyl group include a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group, and a cyclohexenyl group, and the vinyl group is preferred.

[0021] In general formula (I), k is 0 or a positive integer, preferably 0 or a positive integer satisfying 0≦k≦10,000, more preferably 5≦k≦2,000, and more preferably 10≦k≦1,200.

[0022] The organopolysiloxane of component A1 may be an organopolysiloxane having three or more, typically 3 to 30, and preferably about 3 to 20, alkenyl groups having 2 to 8, particularly 2 to 6, carbon atoms bonded to silicon atoms per molecule, such as vinyl groups or allyl groups. The molecular structure of the organopolysiloxane used in combination may be linear, cyclic, branched, or three-dimensional network. The organopolysiloxane used in combination is preferably a linear organopolysiloxane whose main chain is composed of repeating diorganosiloxane units, both molecular chain terminals are blocked with triorganosiloxy groups, and whose viscosity at 25°C is 10 to 1,000,000 mPa·s, particularly 100 to 100,000 mPa·s.

[0023] In organopolysiloxanes containing two or more alkenyl groups bonded to silicon atoms per molecule, the alkenyl groups may be bonded to any part of the molecule. For example, they may be bonded to silicon atoms at the molecular chain terminals or non-terminal locations (in the middle of the molecular chain). Among these, linear organopolysiloxanes represented by the following general formula (II), in which one to three alkenyl groups are bonded to silicon atoms at both molecular chain terminals, and which have a viscosity at 25°C of 10 to 1,000,000 mPa·s are preferred from the viewpoints of workability and curability. However, when the number of alkenyl groups bonded to silicon atoms at the molecular chain terminals of this linear organopolysiloxane is one or two in total, linear organopolysiloxanes in which the alkenyl groups bonded to non-terminal locations (in the middle of the molecular chain) are used as substituents in, for example, diorganosiloxane units are preferred. This linear organopolysiloxane may contain a small amount of branched structure (trifunctional siloxane unit) in the molecular chain.

[0024]

[0025] In the formula, each R 3 may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups, at least one of which is an alkenyl group; 4 may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups that do not have an aliphatic unsaturated bond, R5 is an alkenyl group, and l and m are each independently 0 or a positive integer.

[0026] In general formula (II), R 3 Preferred monovalent hydrocarbon groups include those having 1 to 10 carbon atoms, and particularly 1 to 6 carbon atoms. Specific examples of unsubstituted monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl, phenylethyl, and phenylpropyl; and alkenyl groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl. Examples of the substituted monovalent hydrocarbon group include groups in which some or all of the hydrogen atoms of the unsubstituted monovalent hydrocarbon group have been substituted with halogen atoms such as fluorine, bromine, or chlorine; or a cyano group, such as halogen-substituted alkyl groups such as a chloromethyl group, a chloropropyl group, a bromoethyl group, or a trifluoropropyl group; and a cyanoethyl group.

[0027] In general formula (II), R 4 The unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond is preferably one having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. 4 The unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond includes the above-mentioned R 1 Specific examples of the unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond are the same as those of the group 1, except that alkenyl groups are not included.

[0028] In general formula (II), R 5 The alkenyl group in the formula (I) is preferably an alkenyl group having 2 to 6 carbon atoms, particularly preferably having 2 to 3 carbon atoms. 2 The same groups as those shown in the above are exemplified, and a vinyl group is preferred.

[0029] In general formula (II), l and m are each independently 0 or a positive integer, preferably 0 or a positive integer satisfying 0 < l + m ≦ 10,000, more preferably 5 ≦ l + m ≦ 2,000, even more preferably 10 ≦ l + m ≦ 1,200, and are also preferably an integer satisfying 0 < l / (l + m) ≦ 0.2, and even more preferably 0.0011 ≦ l / (l + m) ≦ 0.1.

[0030] <<Crosslinking Component (Component A2)>> The crosslinking component of component A2 of the present invention is, for example, an organohydrogenpolysiloxane. This organohydrogenpolysiloxane functions as a crosslinking agent. A cured product is formed by addition reaction (hydrosilylation) between SiH groups in this organohydrogenpolysiloxane and alkenyl groups in the organopolysiloxane of component A1. Any organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms (i.e., SiH groups) per molecule can be used as the crosslinking component (component A2). The molecular structure of this organohydrogenpolysiloxane may be linear, cyclic, branched, or a three-dimensional network structure. Furthermore, organohydrogenpolysiloxanes having a number of silicon atoms per molecule (i.e., degree of polymerization) of 2 to 1,000, particularly about 2 to 300, are preferably used as the crosslinking component (component A2).

[0031] The organohydrogenpolysiloxane contains SiH groups as described above. In the organohydrogenpolysiloxane, the position of the SiH groups is not particularly limited, and they may be at the terminals of the molecular chain or at non-terminal locations (in the middle of the molecular chain). Furthermore, examples of organic groups bonded to silicon atoms other than hydrogen atoms include R in the general formula (I). 1 and unsubstituted or substituted monovalent hydrocarbon groups having no aliphatic unsaturated bonds, similar to those shown above.

[0032] An example of the organohydrogenpolysiloxane of component A2 is one represented by the following formula (III).

[0033]

[0034] In the formula, each R 6may be the same or different and are each an alkyl group, a phenyl group, an epoxy group, an acryloyl group, a methacryloyl group, an alkoxy group, or a hydrogen atom, provided that at least two of them are hydrogen atoms. L is an integer of 0 to 1,000, preferably an integer of 0 to 300, and M is an integer of 1 to 200.

[0035] The crosslinking component is preferably contained in an amount of less than 1 mole per mole of silicon-bonded alkenyl groups in the base polymer component (A1).

[0036] The non-reactive silicone oil used as the matrix resin will now be described. The non-reactive silicone oil has a kinematic viscosity of, for example, 50 to 3,000 mm at 25°C. 2 / s, preferably 70 to 2,500 mm 2 / s. Viscosity is measured using a Brooklyn Field type rotational viscometer SP No. 2. If the kinematic viscosity is within the above range, oil bleeding can be kept low. Furthermore, when the heat-resistant resin composition further contains thermally conductive particles, the filling properties of the thermally conductive particles are also improved. The non-reactive silicone oil is a silicone polymer that does not have a reactive group, and examples thereof include dimethylpolysiloxane and diphenylpolysiloxane.

[0037] <Heat-Resistant Auxiliary Agent (Component D)> The cellulose charcoal powder of the heat-resistant auxiliary agent of the present invention is preferably at least one charcoal powder selected from the group consisting of bamboo charcoal powder, charcoal powder, coconut shell charcoal powder, mangrove charcoal powder, plum nut charcoal powder, plum seed charcoal powder, and rice husk charcoal powder. Among these, bamboo charcoal powder, plum nut charcoal powder, plum seed charcoal powder, and charcoal powder are preferred, as they are readily available with uniform particle sizes. These cellulose charcoal powders are made from natural bamboo or wood and fired at high temperatures. Cellulose charcoal powder can be obtained by firing binchotan charcoal (charcoal so carbonized that it makes a metallic sound when struck) at a temperature of, for example, 1000-1200°C, crushing the binchotan, which has been fired and then shaped to a predetermined particle size. Iron black (iron tetroxide), carbon black, etc. have traditionally been used as black pigments, and red iron oxide (ferric oxide) has been used as red pigments. However, these pigments contain metals or ionic components such as sulfur, copper, and cobalt. Therefore, there was the problem of inhibiting the curing of the thermosetting resin as mentioned above, but the cellulose charcoal powder used in the present invention does not contain metal or ionic components, so such a problem does not occur. Furthermore, since the heat-resistant auxiliary agent of the present invention is a cellulose charcoal powder, it also functions as a black pigment.

[0038] The heat resistance aid may be surface-treated with a coupling agent. Examples of the coupling agent include a silane coupling agent, specifically a compound represented by the formula R(CH3) a Si(OR') 4-a(wherein R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), or a partial hydrolyzate thereof. Examples of the silane compound include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. The silane compounds can be used alone or in combination. The heat resistance aid may be surface-treated with preferably 0.1 to 50 parts by mass, more preferably 0.5 to 30 parts by mass of the silane coupling agent, relative to 100 parts by mass of the heat resistance aid, using a stirring degassing device. The silane coupling agent coats the surface of the heat resistance aid (surface treatment), and as a result, the heat resistance aid is more easily filled into the matrix resin (plasticizer function).

[0039] The cellulose charcoal powder preferably has a cumulative particle size distribution D50 (median diameter) of 0.01 to 150 μm on a volume basis, more preferably 0.05 to 130 μm, and even more preferably 0.1 to 100 μm. The cellulose charcoal powder having the above median diameter is suitable for use as a heat resistance aid and a black pigment.

[0040] The cellulose charcoal powder is contained in the heat-resistant resin composition in an amount of 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and even more preferably 1 to 10 parts by mass, per 100 parts by mass of the matrix resin. At this content, the cellulose charcoal powder is suitable as a heat-resistant auxiliary and a black pigment.

[0041] <Thermal Conductive Particles (Component C)> The heat-resistant resin composition of the present invention preferably further contains thermally conductive particles. This is because such a heat-resistant resin composition is useful as a thermally conductive composition. The thermally conductive particles are preferably at least one inorganic particle selected from the group consisting of aluminum oxide (alumina), zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide, and a combination of aluminum oxide (alumina) and aluminum hydroxide is more preferred. These inorganic particles have high thermal conductivity, and heat-resistant resin compositions containing them are suitable as materials for thermal interface materials (TIMs). The D50 (median diameter) of the cumulative particle size distribution based on volume of the thermally conductive particles is preferably 0.01 to 150 μm, more preferably 0.05 to 130 μm, and even more preferably 0.1 to 100 μm.

[0042] The thermally conductive particles can be a mixture of multiple types of thermally conductive inorganic particles with different average particle sizes. This allows smaller thermally conductive inorganic particles to be embedded between larger particles, resulting in a nearly close-packed state, enhancing the thermal conductivity of the cured heat-resistant resin composition. This also results in a cured heat-resistant resin composition with low plasticity and excellent moldability. This also allows the cured heat-resistant resin composition to be molded into a thermal interface material (TIM), which has a low compressive load and is easier to handle than putty-like materials.

[0043] For example, when the total amount of the thermally conductive particles is taken as 100% by mass, the thermally conductive particles preferably contain 50 to 90% by mass of alumina having a D50 (median diameter) of less than 20 μm and 10 to 50% by mass of aluminum hydroxide having a D50 (median diameter) of 20 μm or more, and more preferably contain 60 to 80% by mass of alumina having a D50 (median diameter) of less than 20 μm and 20 to 40% by mass of aluminum hydroxide having a D50 (median diameter) of 20 μm or more.

[0044] The heat-resistant resin composition preferably contains 50 to 3,000 parts by mass of the thermally conductive particles, more preferably 100 to 2,000 parts by mass, and even more preferably 200 to 1,800 parts by mass of the particles per 100 parts by mass of the matrix resin. This amount of addition can increase the thermal conductivity of the heat-resistant resin composition, making the heat-resistant resin composition suitable as a material for a thermal interface material (TIM) or a thermally conductive sheet.

[0045] The thermally conductive particles may be surface-treated with a coupling agent, such as a compound represented by the formula R(CH3) a Si(OR') 4-a (wherein R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), or a partial hydrolyzate thereof. Examples of the silane compound include methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, and octadecyltriethoxysilane. The silane compounds can be used alone or in combination. The thermally conductive particles may be surface-treated with preferably 0.1 to 90 parts by mass, more preferably 0.5 to 85 parts by mass of the silane coupling agent relative to 100 parts by mass of the thermally conductive particles, because the silane coupling agent coats the surfaces of the thermally conductive particles (surface treatment), thereby making it easier for the thermally conductive particles to be filled into a matrix resin (plasticizer function).

[0046] The heat-resistant resin composition may further contain the silane coupling agent in an amount of preferably 0.1 to 10 parts by mass, more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the matrix resin. The silane coupling agent coats the surfaces of the thermally conductive particles and / or the heat-resistant auxiliary (surface treatment), thereby making it easier for the thermally conductive particles and / or the heat-resistant auxiliary to be filled into the matrix resin (plasticizer function).

[0047] <Curing Catalyst (Component B)> The heat-resistant resin composition of the present invention may further contain a curing catalyst. A catalyst used in a hydrosilylation reaction can be used as the curing catalyst. Examples of the curing catalyst include platinum-based catalysts such as platinum black, platinic chloride, chloroplatinic acid, reaction products of chloroplatinic acid with monohydric alcohols, complexes of chloroplatinic acid with olefins or vinylsiloxanes, platinum bisacetoacetate, and other platinum group metal catalysts such as palladium-based catalysts and rhodium-based catalysts. While two-component curing silicone polymers typically contain a platinum group metal catalyst, it is preferable to add an additional platinum group metal catalyst to the heat-resistant resin composition of the present invention. The platinum group metal catalyst is added to control the curing rate of the heat-resistant resin composition.

[0048] The curing catalyst is contained in the heat-resistant resin composition in an amount of, for example, 0.01 to 1,000 parts by mass, preferably 0.1 to 100 parts by mass, and more preferably 0.5 to 50 parts by mass, per 100 parts by mass of the matrix resin (component A).

[0049] <Other Additives> The heat-resistant resin composition of the present invention may contain components other than those described above, as needed. For example, the heat-resistant resin composition may contain a heat resistance improver such as titanium oxide or cerium oxide, a flame retardant aid, or the like. The heat-resistant resin composition may also contain an organic or inorganic pigment for the purpose of coloring or toning. The heat-resistant resin composition may also contain the silane coupling agent described above.

[0050] <Physical Properties of Heat-Resistant Resin Composition> The heat-resistant resin composition preferably has a hardness increase rate of 100% or less, more preferably 10 to 80%, and even more preferably 10 to 50%, after 1000 hours at 150°C relative to the initial ASKER-C hardness. A lower hardness increase rate after 1000 hours at 150°C relative to the initial ASKER-C hardness indicates higher heat resistance of the heat-resistant resin composition.

[0051] The heat-resistant resin composition of the present invention can be cured by heating or the like.

[0052] The heat-resistant resin composition preferably has an ASKER-C hardness (initial value) of 75 or less, more preferably 10 to 75, and even more preferably 15 to 70. Such a heat-resistant resin composition exhibits good conformability to heat-generating bodies and heat-dissipating bodies (heat sinks).

[0053] The heat-resistant resin composition preferably has a breakdown voltage (JIS K6249) of 7 to 16 kV / mm. Such a heat-resistant resin composition can be made into a thermally conductive sheet with high electrical insulation properties.

[0054] The volume resistivity (JIS K6249) of the heat-resistant resin composition is 10 10 ~10 14 Such a heat-resistant resin composition can be made into a thermally conductive sheet having high electrical insulation properties.

[0055] [Heat-resistant resin sheet] The heat-resistant resin composition of the present invention, when molded into a sheet, is highly versatile and suitable as a TIM. The thickness of the heat-resistant resin sheet containing the heat-resistant resin composition is preferably in the range of 0.2 to 10 mm.

[0056] The heat-resistant resin sheet preferably has a hardness increase rate of 100% or less, more preferably 10 to 80%, and even more preferably 10 to 50%, relative to the ASKER-C initial hardness after 1000 hours at 150°C. The lower the hardness increase rate relative to the ASKER-C initial hardness after 1000 hours at 150°C, the higher the heat resistance of the heat-resistant resin sheet.

[0057] The heat-resistant resin sheet preferably has an ASKER-C hardness (initial value) of 75 or less, more preferably 10 to 75, and even more preferably 15 to 70. Such a heat-resistant resin sheet exhibits good conformability to a heat generating body and a heat dissipating body (heat sink).

[0058] The heat-resistant resin sheet preferably has a thermal conductivity of 1 W / m K or more, more preferably 1 to 20 W / m K, and even more preferably 2 to 20 W / m K. Such a heat-resistant resin sheet has high thermal conductivity and is suitable as a heat-dissipating sheet: TIM (Thermal Interface Material) or a thermally conductive sheet.

[0059] [Method for manufacturing a heat-resistant resin sheet] The method for manufacturing a heat-resistant resin sheet of the present invention includes the steps of vacuum-degassing the heat-resistant resin composition, rolling it, forming it into a sheet, and then heat-curing it to obtain a heat-resistant resin sheet. Vacuum degassing can be performed by reducing the pressure of the heat-resistant resin composition to -0.08 to -0.1 Pa and leaving it for about 5 to 10 minutes to degas it. The rolling can be performed by roll-rolling, press-forming, or the like, but roll-rolling is preferred because it allows for continuous production.

[0060] The obtained heat-resistant resin sheet has a substantially uniform composition from the inside to the outside. A sheet with a uniform composition can exhibit uniform physical properties even after being mounted on an electrical or electronic component as a TIM. In one example of roll-rolling, the heat-resistant resin composition is sandwiched between two synthetic resin films and then rolled from above with a roll. The heat-curing conditions for the heat-resistant resin sheet are preferably a temperature of 90 to 120°C and a time of 5 to 180 minutes. In this specification, curing and crosslinking are the same.

[0061] The following description will be made with reference to the drawings. In the following drawings, the same reference numerals indicate the same components. FIG. 1 is a schematic cross-sectional view of a heat-resistant resin sheet according to one embodiment of the present invention incorporated into a heat dissipation structure 10. The heat-resistant resin sheet 11b dissipates heat generated by an electronic component 13, such as a semiconductor element. The heat-resistant resin sheet 11b is fixed to a main surface 12a of the heat spreader 12 facing the electronic component 13, and is sandwiched between the electronic component 13 and the heat spreader 2. The heat-resistant resin sheet 11a is sandwiched between the heat spreader 12 and a heat sink 15. The heat-resistant resin sheets 11a and 11b, together with the heat spreader 2, constitute a heat dissipation member that dissipates heat from the electronic component 13. The heat spreader 12 is formed, for example, in the shape of a rectangular plate and has a main surface 12a facing the electronic component 13 and a sidewall 12b extending along the outer periphery of the main surface 12a. The heat spreader 2 has a heat-resistant resin sheet 11b provided on a main surface 12a surrounded by side walls 12b, and a heat sink 15 provided on another surface 12c opposite the main surface 12a via the heat-resistant resin sheet 11a. The electronic component 13 is, for example, a semiconductor element such as a BGA, and is mounted on a wiring board 14. In this arrangement, the heat-resistant resin sheet functions as a thermally conductive sheet.

[0062] The present invention includes the following aspects: [Item 1] A heat-resistant resin composition comprising a matrix resin made of a thermosetting resin and a heat-resistant aid, wherein the heat-resistant aid is a cellulose charcoal powder.

[0063] [Item 2] The cellulose charcoal powder is at least one charcoal powder selected from the group consisting of bamboo charcoal powder, wood charcoal powder, coconut shell charcoal powder, mangrove charcoal powder, plum nut charcoal powder, plum seed charcoal powder, and rice husk charcoal powder, and is preferably bamboo charcoal powder, plum nut charcoal powder, or wood charcoal powder. The heat-resistant resin composition according to Item 1.

[0064] [Item 3] The cellulose charcoal powder has a cumulative particle size distribution D50 (median diameter) based on volume of 0.01 to 150 μm, preferably 0.05 to 130 μm, and more preferably 0.1 to 100 μm. The heat-resistant resin composition according to item 1 or 2.

[0065] [Item 4] The heat-resistant resin composition according to any one of Items 1 to 3, containing 0.1 to 20 parts by mass, preferably 0.5 to 15 parts by mass, more preferably 1 to 10 parts by mass of the cellulose charcoal powder per 100 parts by mass of the matrix resin.

[0066] [Item 5] The heat-resistant resin composition according to any one of Items 1 to 4, wherein the matrix resin made of the thermosetting resin is at least one resin selected from the group consisting of silicone resin, acrylic resin, fluororubber, epoxy resin, phenolic resin, unsaturated polyester resin, melamine resin, acrylic resin, fluororesin, and non-reactive silicone oil, and is preferably a silicone resin or non-reactive silicone oil.

[0067] [Item 6] The heat-resistant resin composition according to Item 5, wherein the silicone resin comprises a base polymer (component A1) and a crosslinking component (A2).

[0068] [Item 7] The heat-resistant resin composition according to any one of Items 1 to 6, wherein the base polymer component is an organopolysiloxane containing two or more silicon-bonded alkenyl groups per molecule, preferably an organopolysiloxane containing two or more silicon-bonded alkenyl groups per molecule, each alkenyl group having from 2 to 8 carbon atoms, particularly from 2 to 6 carbon atoms, such as vinyl or allyl groups, and more preferably an organopolysiloxane represented by general formula (I) containing alkenyl groups bonded to silicon atoms at both molecular chain terminals per molecule, or a linear organopolysiloxane represented by general formula (II) having from 1 to 3 alkenyl groups on each silicon atom at both molecular chain terminals.

[0069]

[0070] In the formula, each R 1 may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups that do not have an aliphatic unsaturated bond, R 2 is an alkenyl group, and k is 0 or a positive integer.

[0071]

[0072] In the formula, each R 3may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups, at least one of which is an alkenyl group; 4 may be the same or different and are unsubstituted or substituted monovalent hydrocarbon groups that do not have an aliphatic unsaturated bond, R 5 is an alkenyl group, and l and m are each independently 0 or a positive integer.

[0073] [Item 8] The heat-resistant resin composition according to any one of Items 1 to 7, wherein the crosslinking component is an organohydrogenpolysiloxane, preferably an organohydrogenpolysiloxane having two or more hydrogen atoms bonded to silicon atoms (i.e., SiH groups) in one molecule, and more preferably an organohydrogenpolysiloxane represented by general formula (III):

[0074]

[0075] In the above formula, each R 6 may be the same or different and are each an alkyl group, a phenyl group, an epoxy group, an acryloyl group, a methacryloyl group, an alkoxy group, or a hydrogen atom, provided that at least two of them are hydrogen atoms. L is an integer of 0 to 1,000, preferably an integer of 0 to 300, and M is an integer of 1 to 200.

[0076] [Item 9] The heat-resistant resin composition according to any one of Items 1 to 8, further comprising a curing catalyst. The curing catalyst is a catalyst used in a hydrosilylation reaction, and is preferably a platinum group metal catalyst such as platinum black, platinic chloride, chloroplatinic acid, a reaction product of chloroplatinic acid with a monohydric alcohol, a complex of chloroplatinic acid with an olefin or vinylsiloxane, a complex of platinum with vinyldisiloxane, platinum bisacetoacetate, or the like; a palladium catalyst; or a rhodium catalyst.

[0077] [Item 10] The heat-resistant resin composition according to Item 9, wherein the curing catalyst is contained in an amount of, for example, 0.01 to 1,000 parts by mass, preferably 0.1 to 100 parts by mass, and more preferably 0.5 to 50 parts by mass, per 100 parts by mass of the matrix resin (component A).

[0078] [Item 11] The heat-resistant resin composition preferably further contains thermally conductive particles, and the thermally conductive particles are more preferably at least one inorganic particle selected from the group consisting of aluminum oxide (alumina), zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide. The heat-resistant resin composition according to any one of Items 1 to 10.

[0079] [Item 12] The thermally conductive particles have a cumulative particle size distribution D50 (median diameter) of 0.01 to 150 μm, preferably 0.05 to 130 μm, more preferably 0.1 to 100 μm. Item 11. The heat-resistant resin composition according to item 11.

[0080] [Item 13] The heat-resistant resin composition according to Item 11 or 12, wherein the thermally conductive particles preferably contain 50 to 90 mass% of alumina having a D50 (median diameter) of less than 20 μm and 10 to 50 mass% of aluminum hydroxide having a D50 (median diameter) of 20 μm or more, when the total amount of the thermally conductive particles is 100 mass%, and more preferably contain 60 to 80 mass% of alumina having a D50 (median diameter) of less than 20 μm and 20 to 40 mass% of aluminum hydroxide having a D50 (median diameter) of 20 μm or more.

[0081] [Item 14] The heat-resistant resin composition according to any one of Items 11 to 13, comprising 50 to 3,000 parts by mass, preferably 100 to 2,000 parts by mass, and more preferably 200 to 1,800 parts by mass of the thermally conductive particles relative to 100 parts by mass of the matrix resin.

[0082] [Item 15] The heat-resistant resin composition according to any one of Items 11 to 14, wherein at least a portion of the thermally conductive particles are surface-treated with a coupling agent.

[0083] [Item 16] The coupling agent is a silane coupling agent, preferably a silane coupling agent represented by the formula R(CH3) a Si(OR') 4-a(R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), or a partial hydrolyzate thereof, more preferably methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, or octadecyltriethoxysilane.

[0084] [Item 17] The heat-resistant resin composition according to any one of Items 11 to 16, wherein the heat-resistant resin composition is a thermally conductive composition.

[0085] [Item 18] The heat-resistant resin composition according to any one of items 1 to 16, wherein the heat-resistant auxiliary is surface-treated with a coupling agent.

[0086] [Item 19] The coupling agent is a compound of the formula R(CH3) a Si(OR') 4-a Item 19. The heat-resistant resin composition according to Item 18, wherein the silane compound is a silane compound represented by the formula (I) (wherein R is an unsubstituted or substituted organic group having 1 to 20 carbon atoms, R' is an alkyl group having 1 to 4 carbon atoms, and a is 0 or 1), or a partial hydrolyzate thereof, preferably methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, pentyltrimethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, octadecyltrimethoxysilane, or octadecyltriethoxysilane.

[0087] [Item 20] The hardness increase rate after holding at 150 ° C. for 1000 hours relative to the ASKER-C initial hardness is 100% or less, preferably 10 to 80%, more preferably 10 to 50%. The heat-resistant resin composition according to any one of items 1 to 19.

[0088] [Item 21] The heat-resistant resin composition according to any one of items 1 to 20, wherein the ASKER-C hardness (initial) is 75 or less, preferably 10 to 75, more preferably 15 to 70.

[0089] [Item 22] A heat-resistant resin sheet comprising the heat-resistant resin composition according to any one of items 1 to 21 and formed into a sheet.

[0090] [Item 23] The heat-resistant resin sheet according to item 22, having a thermal conductivity of 1 W / m K or more, preferably 1 to 20 W / m K, more preferably 2 to 20 W / m K.

[0091] [Item 24] The heat-resistant resin sheet according to item 22 or 23, wherein the thickness of the heat-resistant resin sheet is in the range of 0.2 to 10 mm.

[0092] [Item 25] A thermally conductive sheet comprising the heat-resistant resin composition according to any one of items 1 to 21 and formed into a sheet.

[0093] [Item 26] The thermal conductive sheet according to item 25, having a thermal conductivity of 1 W / m K or more, preferably 1 to 20 W / m K, more preferably 2 to 20 W / m K.

[0094] [Item 27] ​​The thermally conductive sheet according to item 25 or 26, wherein the thickness of the thermally conductive sheet is in the range of 0.2 to 10 mm.

[0095] [Item 28] The heat-resistant resin composition according to any one of items 1 to 21 is vacuum degassed, rolled, sheet-formed, and then heat-cured to obtain a heat-resistant resin sheet. A method for producing a heat-resistant resin sheet.

[0096] [Examples] The present invention will be explained below using examples, but is not limited to these examples. Various parameters were measured by the methods described below.

[0097] <Thermal Conductivity> The thermal conductivity of the heat-resistant resin sheet was measured using a hot disk (compliant with ISO 22007-2:2008). As shown in Figure 2A, this thermal conductivity measuring device 1 sandwiches a polyimide film sensor 2 between two samples 3a and 3b, applies a constant power to the sensor 2, and generates a constant amount of heat, analyzing the thermal characteristics from the temperature rise of the sensor 2. The sensor 2 has a 7 mm diameter tip 4 and, as shown in Figure 2B, has a double spiral electrode structure with an applied current electrode 5 and a resistance value electrode (temperature measurement electrode) 6 located at the bottom. The thermal conductivity is calculated using the following equation (Equation 1).

[0098]

[0099] <Initial Hardness> The initial hardness was measured using an ASKER-C hardness tester immediately after the preparation of the heat-resistant resin composition, and this was defined as the initial ASKER-C hardness (A).

[0100] <Hardness Increase Rate> The hardness after 1000 hours at 150°C was measured using an ASKER-C hardness tester after placing the heat-resistant resin composition in an oven at 150°C and holding it for 1000 hours. This was taken as the hardness (B) after 1000 hours at 150°C. The hardness increase rate was calculated from the data of the initial ASKER-C hardness (A) and the hardness (B) after 1000 hours at 150°C using the following formula: Hardness increase rate = [(B - A) / A] x 100 A: initial ASKER-C hardness B: hardness after 1000 hours at 150°C

[0101] <Viscosity> The initial viscosity of the heat-resistant resin composition (thickness at the time of measurement: 0.5 mm) immediately after preparation was measured using a viscosity and viscoelasticity measuring device MARSIII (manufactured by HAAKE) at a rotational speed of 1.0 (1 / s) and 25°C. The viscosity after 150°C and 1000 hours (hours) was measured using a viscosity and viscoelasticity measuring device MARSIII (manufactured by HAAKE) at a rotational speed of 1.0 (1 / s) and 25°C after storing the heat-resistant resin composition in a constant temperature bath at 150°C for 1000 hours. The viscosity increase rate after 150°C and 1000 hours was calculated from the obtained viscosity value using the following formula: Viscosity increase rate after 150°C and 1000 hours = [(Y-X) / X] x 100 X: initial viscosity Y: viscosity after 150°C and 1000 hours

[0102] Example 1 1. Materials (1) Matrix Resin (Component A): A total of 100 g of a commercially available two-component silicone polymer (addition-curing silicone) containing polyorganosiloxane was used. One component (Component A) contained a base polymer component (polyorganosiloxane, Component A1 of Component A) and a platinum group metal catalyst. The other component (Component B) contained a base polymer component (polyorganosiloxane, Component A1 of Component A) and a crosslinker component (Component A2 of Component A), an organohydrogenpolysiloxane. The mass ratio of Components A and B was A:B = 100:100. This two-component silicone polymer was addition-cured to form a silicone resin by mixing at room temperature. (2) Curing Catalyst (Component B): 0.5 g of a commercially available platinum catalyst was used. (3) Thermally Conductive Particles (Component C): Thermally conductive particles listed in Table 1 were used. The average particle size is the D50 (median diameter) of the cumulative particle size distribution on a volume basis measured by laser diffraction light scattering. 512 g of alumina (C1) with a D50 (median diameter) of 4.6 μm and 232 g of aluminum hydroxide (C2) with a D50 (median diameter) of 49 μm were used. An example of a device for measuring the median diameter is the LA-950S2 laser diffraction / scattering particle distribution analyzer manufactured by Horiba, Ltd. (C1): Alumina (D50 = 4.6 μm, of which 82% by mass was surface-treated with a silane coupling agent (decyltrimethoxysilane)). (C2): Aluminum hydroxide (D50 = 49 μm). (4) Heat-resistant additive (component D): 7 g of commercially available bamboo charcoal powder (manufactured by Suncall Co., Ltd., product name "Kyo Kaguya Charcoal", D50 (median diameter) = 1.8 μm) was used. FIG. 3 shows an enlarged SEM photograph (1000x magnification) of this bamboo charcoal powder.

[0103] 2. Heat-resistant resin composition The amounts of each material shown in Table 1 were weighed out and placed in a mixer to obtain a heat-resistant resin composition. In Table 1, the numerical values ​​for each material indicate parts by mass (g). This heat-resistant resin composition was degassed under a reduced pressure of -0.1 Pa for 5 minutes.

[0104] The heat-resistant resin composition was sandwiched between release-treated polyethylene terephthalate (PET) films, rolled using a constant speed roll into a sheet having a thickness of 2.0 mm, and then heat-cured at 100°C for 10 minutes to form a heat-resistant resin sheet having a thickness of 2.0 mm. The thermal conductivity of this heat-resistant resin sheet was 2.3 W / m K.

[0105] Example 2 A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that the amount of bamboo charcoal powder added was 3.5 g.

[0106] Example 3 A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that the amount of bamboo charcoal powder added was 1.75 g.

[0107] Example 4 A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that bamboo charcoal powder having a D50 (median diameter) of 5.0 μm was used instead of the bamboo charcoal powder having a D50 (median diameter) of 1.8 μm.

[0108] [Example 5] A heat-resistant resin sheet was obtained in the same manner as in Example 2, except that plum seed charcoal powder (manufactured by Furusato Food Research Institute Co., Ltd., product name "Plum Seed Charcoal Powder") having a D50 (median diameter) of 5.6 μm was used instead of bamboo charcoal powder having a D50 (median diameter) of 1.8 μm.

[0109] Comparative Example 1 A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that the heat-resistant auxiliary (component D) was not added.

[0110] Comparative Example 2 A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that 7 g of iron black (D50 (median diameter) 0.17 μm), a conventional color pigment, was added instead of the heat-resistant auxiliary (component D).

[0111] The composition of the heat-resistant resin composition and the results of various parameters of the obtained heat-resistant resin composition and heat-resistant resin sheet are shown in Tables 1 and 2. In addition, a graph showing the results of ASKER-C hardness when the heat-resistant resin sheet was stored in a thermostatic chamber at 150°C for up to 1000 hours is shown in Figure 4.

[0112]

[0113]

[0114] As can be seen from Tables 1 and 2 and FIG. 4, in Examples 1 to 5 of the present invention, the heat-resistant resin sheets had an ASKER-C hardness increase rate of 50% or less after being stored in a constant temperature bath at 150°C for 1000 hours. This confirmed that the heat resistance was significantly higher than that of Comparative Example 1 (205%) and Comparative Example 2 (170%).

[0115] Example 6: Commercially available bamboo charcoal powder (manufactured by Suncall Co., Ltd., trade name "Kyo Kaguya Charcoal," D50 (median diameter) = 1.8 μm) and a silane coupling agent (decyltrimethoxysilane) were placed in a container at a bamboo charcoal powder:silane coupling agent mass ratio of 10:1, and the mixture was surface-treated by stirring using a planetary stirring and degassing device. A heat-resistant resin sheet was obtained in the same manner as in Example 1, except that 17 g of this surface-treated bamboo charcoal powder was used instead of 7 g of commercially available bamboo charcoal powder (manufactured by Suncall Co., Ltd., trade name "Kyo Kaguya Charcoal," D50 (median diameter) = 1.8 μm). The resulting heat-resistant resin sheet maintained its shape, and the PET film could be cleanly peeled off, maintaining its shape. Therefore, it was confirmed that the heat-resistant resin sheet of Example 6 exhibited excellent curability.

[0116] [Example 7] 1. Materials (1) Matrix resin (Component A): Commercially available dimethyl silicone oil (kinematic viscosity at 25°C: 1,800 mm 2100 g of (1000 μm / s) was used. (2) Curing catalyst (component B): Not used. (3) Thermally conductive particles (component C): Thermally conductive particles listed in Table 3 were used. The average particle size is the D50 (median diameter) of the cumulative particle size distribution on a volume basis, measured by laser diffraction light scattering. 614.4 g of alumina (C1) with a D50 (median diameter) of 4.6 μm and 278.4 g of aluminum hydroxide (C2) with a D50 (median diameter) of 49 μm were used. An example of an instrument for measuring the median diameter is the LA-950S2 laser diffraction / scattering particle distribution analyzer manufactured by Horiba, Ltd. (C1): Alumina (D50 = 4.6 μm, of which 82 mass% was surface treated with a silane coupling agent (decyltrimethoxysilane)) (C2): Aluminum hydroxide (D50 = 49 μm) (4) Heat resistance aid (Component D): 3.5 g of commercially available bamboo charcoal powder (manufactured by Suncall Co., Ltd., trade name "Kyoto Kaguya Charcoal", D50 (median diameter) = 1.8 μm) was used.

[0117] 2. Heat-resistant resin composition The amounts of each material shown in Table 3 were weighed out and placed in a mixer to obtain a heat-resistant resin composition. In Table 3, the numerical values ​​for each material indicate parts by mass (g). This heat-resistant resin composition was degassed under a reduced pressure of -0.1 Pa for 5 minutes.

[0118] Comparative Example 3 A heat-resistant resin composition was obtained in the same manner as in Example 7, except that the heat-resistant auxiliary (component D) was not used.

[0119] Comparative Example 4 A heat-resistant resin composition was obtained in the same manner as in Example 7, except that 3.5 g of iron black (D50 (median diameter) = 0.2 μm), a conventional color pigment, was added instead of the heat-resistant auxiliary (component D).

[0120] The composition of the heat-resistant resin composition and the results of various parameters of the obtained heat-resistant resin composition are shown in Tables 3 and 4. A graph showing the change in viscosity of the heat-resistant resin composition over time is shown in Figure 5.

[0121]

[0122]

[0123] As shown in Tables 3 and 4 and Fig. 5, it was confirmed that even in the case of an uncured heat-resistant resin composition, Example 7 containing the heat-resistant auxiliary (D) was able to suppress the viscosity increase rate after storage at 150°C for 1000 hours. In other words, it was confirmed that the heat-resistant resin composition of the present invention was able to suppress the viscosity increase rate even after storage at high temperatures and had excellent heat resistance.

[0124] The heat-resistant resin composition and heat-resistant resin sheet of the present invention are suitable as a heat-dissipating sheet (TIM (Thermal Interface Material)) or a thermally conductive sheet to be interposed between a heat-generating part of an electric or electronic part and a heat sink.

[0125] [Explanation of symbols] 1 Thermal conductivity measuring device 2 Sensor 3a, 3b Sample 4 Sensor tip 5 Electrode for applied current 6 Electrode for resistance value (electrode for temperature measurement) 10 Heat dissipation structure 11a, 11b Heat-resistant resin sheet 12 Heat spreader 13 Electronic component 14 Wiring board 15 Heat sink

Claims

1. A heat-resistant resin composition comprising a matrix resin made of a thermosetting resin and a heat-resistant aid, wherein the heat-resistant aid is cellulose carbon powder.

2. The heat-resistant resin composition according to claim 1, wherein the cellulose carbon powder is at least one carbon powder selected from the group consisting of bamboo charcoal powder, charcoal powder, coconut shell charcoal powder, mangrove charcoal powder, ume fruit charcoal powder, ume seed charcoal powder, and rice husk charcoal powder.

3. The heat-resistant resin composition according to claim 1 or 2, wherein the cellulose carbon powder has a D50 (median diameter) of the cumulative particle size distribution based on volume in the range of 0.01 to 150 μm.

4. The heat-resistant resin composition according to any one of claims 1 to 3, comprising 0.1 to 20 parts by mass of the cellulose carbon powder with respect to 100 parts by mass of the matrix resin.

5. The heat-resistant resin composition according to any one of claims 1 to 4, wherein the matrix resin made of the thermosetting resin is at least one resin selected from the group consisting of silicone resin, acrylic resin, fluororubber, epoxy resin, phenolic resin, unsaturated polyester resin, melamine resin, acrylic resin, fluororesin, and non-reactive silicone oil.

6. The heat-resistant resin composition according to any one of claims 1 to 5, further comprising heat-conductive particles, wherein the heat-conductive particles are at least one inorganic particle selected from the group consisting of aluminum oxide (alumina), zinc oxide, magnesium oxide, aluminum nitride, boron nitride, aluminum hydroxide, and silicon carbide.

7. The heat-resistant resin composition according to any one of claims 1 to 6, comprising 50 to 3,000 parts by mass of the heat-conductive particles with respect to 100 parts by mass of the matrix resin.

8. The heat-resistant resin composition according to claim 6 or 7, wherein at least a part of the heat-conductive particles is surface-treated with a coupling agent.

9. The heat-resistant resin composition according to any one of claims 1 to 8, wherein the hardness increase rate after holding at 150 °C for 1,000 hours is 100% or less with respect to the initial Asker-C hardness.

10. A heat-resistant resin sheet formed in a sheet shape and comprising the heat-resistant resin composition according to any one of claims 1 to 9.

11. The heat-resistant resin sheet according to claim 10, wherein the thickness of the heat-resistant resin sheet is in the range of 0.2 to 10 mm.

12. A method for manufacturing a heat-resistant resin sheet, comprising a step of subjecting the heat-resistant resin composition according to any one of claims 1 to 9 to vacuum degassing, rolling, sheet forming, and then heat curing to obtain a heat-resistant resin sheet.

Images