Heat-dissipating resin composition and cured product thereof

Abstract

The purpose of the present invention is to provide a heat-dissipating resin composition which is free of siloxanes and can yield a cured product having excellent durability at high temperatures. The present invention relates to a heat-dissipating resin composition which contains components (A) to (C), component (A) including component (A-1) and component (A-2).　Component (A) is a crosslinkable silyl group-containing organic polymer. Component (A-1) is a vinyl-based polymer having one or more crosslinkable silyl groups in the molecule. Component (A-2) is an organic polymer having two or more crosslinkable silyl groups in the molecule (excluding component (A-1)). Component (B) is a heat-dissipating filler. Component (C) is a curing catalyst containing a zinc compound.

Description

Heat-dissipating resin composition and cured product thereof

[0001] The present invention relates to a heat-dissipating resin composition and a cured product thereof.

[0002] In recent years, with the improvement in the performance of electronic and electrical devices such as personal computers and smartphones, and batteries, the increase in the amount of heat generated by these components during operation has become a problem. Heat-dissipating resin compositions are used to dissipate this heat to the outside. As an example of a heat-dissipating resin composition, a heat-dissipating silicone resin composition is disclosed in, for example, JP 2004-352947 A (corresponding to U.S. Patent Application Publication No. 2004 / 0242762 A). Heat dissipation is achieved by contacting a heat-dissipating silicone resin obtained by curing this composition with a high-temperature component. However, upon contact, low-molecular-weight siloxane components and cyclic siloxane components may volatilize, resulting in poor contact and other problems. To address this issue, for example, JP 2010-053331 A discloses a heat-dissipating resin composition using a crosslinkable silyl group-containing organic polymer.

[0003] However, the heat-dissipating resin composition using a crosslinkable silyl group-containing organic polymer as disclosed in JP 2010-053331 A has a problem in that when exposed to high temperatures for a long period of time, the resin (cured product) undergoes a volume change due to shrinkage, resulting in deterioration of the properties and sealing ability as a heat-dissipating resin.

[0004] Therefore, an object of the present invention is to provide a heat-dissipating resin composition that can give a cured product that has excellent durability at high temperatures.

[0005] Another object of the present invention is to provide a heat-dissipating resin composition having excellent adhesive properties.

[0006] The present inventors have conducted extensive research to solve the above problems, and as a result have completed the present invention, which relates to a heat-dissipating resin composition.

[0007] The gist of the present invention will now be described. [1] A heat-dissipating resin composition comprising the following components (A) to (C), wherein the component (A) comprises the following components (A-1) and (A-2): component (A): a crosslinkable silyl group-containing organic polymer; component (A-1): a vinyl polymer having one or more crosslinkable silyl groups in the molecule; component (A-2): an organic polymer having two or more crosslinkable silyl groups in the molecule (excluding component (A-1)); component (B): a heat-dissipating filler; and component (C): a curing catalyst containing a zinc compound; [2] The heat-dissipating resin composition according to [1], wherein the component (A-2) is an organic polymer having a polyoxyalkylene skeleton; [3] The heat-dissipating resin composition according to [1] or [2], wherein the component (A-1) and the component (A-2) have crosslinkable silyl groups at at least two ends of the main chain skeleton; [4] The heat-dissipating resin composition according to any one of [1] to [3], wherein the component (B) contains alumina powder; [5] The heat-dissipating resin composition according to any one of [1] to [4], wherein the component (B) comprises the following component (B-1) and component (B-2): component (B-1): a heat-dissipating filler having an average particle size of 0.01 μm or more and less than 10 μm; component (B-2): a heat-dissipating filler having an average particle size of 10 μm or more and 150 μm or less; [6] The heat-dissipating resin composition according to any one of [1] to [5], wherein the volume-based particle size distribution of the component (B) has two or three or more peaks, and at least one peak appears in each of a region where the particle size is 0.01 μm or more and less than 10 μm and a region where the particle size is 10 μm or more and 150 μm or less; [7] The heat-dissipating resin composition according to any one of [1] to [6], wherein the component (A) consists only of the component (A-1) and the component (A-2); [8] The heat-dissipating resin composition according to any one of [1] to [7], wherein the mass ratio of the component (A-1) to the component (A-2) (total mass of the components (A-1):total mass of the components (A-2)) is 80:20 to 20:80; [9] The heat-dissipating resin composition according to any one of [1] to [8], further comprising an amino group-containing silane coupling agent;

[10] The heat-dissipating resin composition according to any one of [1] to [9], wherein the volume change rate of a cured product obtained by curing the heat-dissipating resin composition before and after a load test is 0% by mass or more and 2.0% or less, and the load test is carried out by leaving the cured product at rest at a temperature of 120°C for 240 hours;

[11] A cured product obtained by curing the heat-dissipating resin composition according to any one of [1] to

[10] ;

[12] A method for producing the heat-dissipating resin composition according to any one of [1] to

[10] , comprising sequentially or simultaneously mixing the following components (B-1) and (B-2) with either one of the components (A) and (C), or with a mixture containing at least one of the components (A) and (C): component (B-1): a heat-dissipating filler having an average particle size of 0.01 μm or more and less than 10 μm; and component (B-2): a heat-dissipating filler having an average particle size of 10 μm or more and 150 μm or less.

[0008] The present invention will be described in detail below. In this specification, "X to Y" refers to the numerical values ​​(X and Y) before and after the term "X" and "Y" as upper and lower limits, meaning "X or greater but Y or less." When multiple "X to Y" are listed, for example, when "X1 to Y1" or "X2 to Y2" is listed, the disclosure of each numerical value as an upper limit, the disclosure of each numerical value as a lower limit, and combinations of these upper and lower limits are all disclosed (i.e., they serve as legitimate grounds for amendment). Specifically, amendments to X1 or greater, amendments to Y2 or less, amendments to X1 or less, amendments to Y2 or greater, amendments between X1 and X2, and amendments between X1 and Y2 must all be deemed legitimate. In this specification, the term "(meth)acrylic" refers to both acrylic and methacrylic. Furthermore, "A and / or B" refers to each of A and B, as well as combinations thereof.

[0009] One embodiment of the present invention is a heat-dissipating resin composition comprising the following components (A) to (C), wherein the component (A) comprises the following components (A-1) and (A-2):

[0010] Component (A): a crosslinkable silyl group-containing organic polymer; Component (A-1): a vinyl polymer having one or more crosslinkable silyl groups in the molecule; Component (A-2): an organic polymer having two or more crosslinkable silyl groups in the molecule (excluding component (A-1)); Component (B): a heat-dissipating filler; and Component (C): a curing catalyst containing a zinc compound.

[0011] According to the present invention, it is possible to provide a heat-dissipating resin composition that is siloxane-free and has excellent durability at high temperatures when cured, and also has excellent adhesive properties.

[0012] A heat-dissipating resin composition according to one embodiment of the present invention essentially contains components (A) to (C). By including component (B), a cured product of the heat-dissipating resin composition can exhibit good heat dissipation properties. The composition further includes component (A-1), which is a vinyl polymer having one or more crosslinkable silyl groups in its molecule, and component (A-2), which is an organic polymer having two or more crosslinkable silyl groups in its molecule. It is presumed that the combination of component (A-1), which has a rigid skeleton, and component (A-2), which has a flexible skeleton and two crosslinkable moieties, can reduce the volume change rate upon exposure to high temperatures. Furthermore, it is presumed that the inclusion of component (C) in the heat-dissipating resin composition favorably promotes the crosslinking reaction, thereby achieving the above-mentioned effects. The above mechanism is based on speculation, and whether it is correct or incorrect does not affect the technical scope of the present invention.

[0013] <Component (A)> The component (A) that can be used in the present invention is a crosslinkable silyl group-containing organic polymer. There are no particular limitations on the number of crosslinkable silyl groups present in the molecule, as long as there is one or more, but from the perspective of reactivity, it is preferable that there be two or more crosslinkable silyl groups present in the molecule. Furthermore, the crosslinkable silyl groups may be present in either the side chains and / or terminals of the molecule, but it is preferable that they be present at the terminals, as this provides excellent suppression of volume change when the cured product is exposed to high temperatures. The component (A) may be used alone or in combination of two or more types.

[0014] The crosslinkable silyl group contained in component (A) is a functional group having one to three crosslinkable groups bonded to a silicon atom. The crosslinking reaction proceeds, for example, by a condensation reaction between two crosslinkable silyl groups to form a siloxane bond (Si—O—Si) or by forming a crosslink via a nitrogen atom (i.e., forming a Si—N—Si bond). Examples of the crosslinkable group include an alkoxy group (alkyloxy group), an alkenyloxy group, an alkynyloxy group, an acyloxy group (acyloxy group), an amino group, an aminooxy group, an oxime group, and an amide group. Of these, the crosslinkable group is preferably selected from an alkoxy group, an alkenyloxy group, and an acyloxy group, with an alkoxy group being particularly preferred.

[0015] In this specification, unless otherwise specified, an "amino group" is defined as -NH ２ , —NHR (R is an alkyl group having 1 to 20 carbon atoms), and —NR′R″ (R′ and R″ are each independently an alkyl group having 1 to 20 carbon atoms). Unless otherwise specified, in this specification, the “aminooxy group” refers to —O—NH ２ , —O-NHR (R is an alkyl group having 1 to 20 carbon atoms), and —O-NR'R" (R' and R" are each independently an alkyl group having 1 to 20 carbon atoms). Unless otherwise specified, in this specification, an "oxime group" includes —NH-OH and —NR-OH (R is an alkyl group having 1 to 20 carbon atoms).

[0016] The alkoxy group is not particularly limited, but is, for example, a linear or branched alkoxy group having 1 to 20 carbon atoms, preferably a linear or branched alkoxy group having 1 to 8 carbon atoms, more preferably a methoxy group, an ethoxy group, an n-propoxy group, or an isopropoxy group, still more preferably a methoxy group or an ethoxy group, and particularly preferably a methoxy group.

[0017] Furthermore, a group other than the crosslinkable group may be bonded to the silicon atom of the crosslinkable silyl group, and examples of the group other than the crosslinkable group include a hydrogen atom, a deuterium atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and an arylalkyl group. Among these, an alkyl group is preferred, a linear or branched alkyl group having 1 to 20 carbon atoms is more preferred, a linear or branched alkyl group having 1 to 8 carbon atoms is even more preferred, and a methyl group, an ethyl group, a propyl group, or an isopropyl group is particularly preferred.

[0018] The crosslinkable silyl group may be represented by the following chemical formulas (1) to (3).

[0019]

[0020] In the above chemical formulas (1) to (3), X １ , X ２１ ~X ２２ , and X ３１ ~X ３３ are each independently an alkoxy group (alkyloxy group), an alkenyloxy group, an alkynyloxy group, an acyloxy group (acyloxy group), an amino group, an aminooxy group, an oxime group, or an amido group, and R １１ ~R １２ and R ２ are each independently a hydrogen atom, a deuterium atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or an arylalkyl group, and * (asterisk) indicates a bonding point to another atom.

[0021] In one embodiment, X in the above chemical formulas (1) to (3) １ , X ２１ ~X ２２ , and X ３１ ~X ３３ represents a crosslinkable group, R １１ ~R １２ and R ２ represents a group that is not a crosslinkable group.

[0022] X in the above chemical formulas (1) to (3) １ , X ２１ ~X ２２ , and X ３１ ~X３３ are each independently a linear or branched chain alkoxy group having 1 to 8 carbon atoms, a linear or branched chain alkenyloxy group having 2 to 8 carbon atoms, a linear or branched chain alkynyloxy group having 2 to 8 carbon atoms, a linear or branched chain acyloxy group having 1 to 8 carbon atoms, a linear or branched chain amino group having 0 to 16 carbon atoms, a linear or branched chain aminooxy group having 0 to 16 carbon atoms, a linear or branched chain oxime group having 0 to 8 carbon atoms, and a linear or branched chain amide group having 1 to 8 carbon atoms. It may be a group selected from the group consisting of straight-chain or branched-chain alkoxy groups having 1 to 8 carbon atoms, preferably a group selected from the group consisting of straight-chain or branched-chain alkenyloxy groups having 2 to 8 carbon atoms, straight-chain or branched-chain alkynyloxy groups having 2 to 8 carbon atoms, and straight-chain or branched-chain acyloxy groups having 1 to 8 carbon atoms, more preferably a straight-chain or branched-chain alkoxy group having 1 to 8 carbon atoms, and particularly preferably a methoxy group or an ethoxy group.

[0023] In the above chemical formulas (1) to (3), R １１ ~R １２ and R ２ may each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a linear or branched alkenyl group having 2 to 8 carbon atoms, a linear or branched alkynyl group having 2 to 8 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an arylalkyl group having 7 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 8 carbon atoms, and particularly preferably a methyl group or an ethyl group.

[0024] The crosslinkable silyl group is preferably a group having 2 to 3 crosslinkable groups. In one embodiment, the crosslinkable silyl group is preferably a group represented by the above chemical formulas (2) to (3).

[0025] In one embodiment, the crosslinkable silyl group is preferably a group selected from the group consisting of a methoxydimethylsilyl group, an ethoxydimethylsilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a trimethoxysilyl group, and a triethoxysilyl group, and more preferably a dimethoxymethylsilyl group or a trimethoxysilyl group.

[0026] Examples of organic polymers constituting the main chain of component (A) include vinyl polymers, polyoxyalkylenes, polyesters, polyamides, polycarbonates, and polyisobutylenes. From the viewpoint of suppressing volume change upon exposure to high temperatures and achieving excellent curing properties, component (A) preferably includes an organic polymer having a vinyl polymer skeleton and an organic polymer having a skeleton other than a vinyl polymer skeleton, and more preferably includes an organic polymer having a vinyl polymer skeleton and an organic polymer having a polyoxyalkylene skeleton. In one embodiment, component (A) preferably consists solely of component (A-1), a vinyl polymer having one or more crosslinkable silyl groups, and component (A-2), an organic polymer having two or more crosslinkable silyl groups in its molecule (excluding component (A-1)). In this specification, the term "consisting only of" encompasses not only embodiments containing only a specific compound, but also embodiments substantially free of compounds other than the specific compound.

[0027] The mass ratio of the (A-1) component to the (A-2) component ((A-1) component:(A-2) component) is preferably 90:10 to 10:90, more preferably 80:20 to 20:80, and most preferably 75:25 to 25:75. When the mass ratio of the (A-1) component to the (A-2) component is within the above range, the cured product is more excellent in suppressing volume change when exposed to high temperatures. In one embodiment, the mass ratio of the (A-1) component to the (A-2) component ((A-1) component:(A-2) component) may be 75:25 to 50:50, and preferably 70:30 to 55:45.

[0028] The component (A-1) is a vinyl polymer having one or more crosslinkable silyl groups in the molecule. There are no particular limitations on the number of crosslinkable silyl groups in the molecule, as long as there is one or more crosslinkable silyl groups in the molecule, and they may be present either on a side chain or at the end of the molecule. However, from the viewpoint of adhesive strength and curability, it is preferable for there to be two or more crosslinkable silyl groups in the molecule, and it is more preferable for them to be present at at least two ends (for example, both ends) of the main chain. There is no particular limitation on the upper limit of the number of crosslinkable silyl groups, but it may be 5 or less, and preferably 3 or less. The component (A-1) may be used alone, or two or more types may be used in combination.

[0029] The crosslinkable silyl group of component (A-1) is as described above. The crosslinkable silyl group of component (A-1) is preferably a group having two to three crosslinkable groups, and more preferably a group having two crosslinkable groups. In one embodiment, the crosslinkable silyl group of component (A-1) is preferably a group represented by the above chemical formulas (2) to (3), and more preferably a group represented by the above chemical formula (2). Furthermore, the crosslinkable silyl group of component (A-1) is preferably an alkoxysilyl group. Examples of the alkoxysilyl group include a methoxydimethylsilyl group, an ethoxydimethylsilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a trimethoxysilyl group, and a triethoxysilyl group. However, a dialkoxysilyl group is preferred in terms of its excellent ability to suppress volume change when the cured product is exposed to high temperatures, and a dimethoxymethylsilyl group or a diethoxymethylsilyl group is more preferred, and a dimethoxymethylsilyl group is most preferred.

[0030] A vinyl polymer means a polymer having a vinyl polymer skeleton as a main chain skeleton. A vinyl polymer skeleton means a skeleton obtained by polymerizing a vinyl monomer. A vinyl polymer may be a homopolymer obtained by polymerizing one monomer, or a copolymer obtained by polymerizing two or more monomers. In the case of a copolymer, the vinyl polymer also includes a skeleton obtained by polymerizing a monomer other than a vinyl monomer in addition to a vinyl monomer. In this specification, a vinyl monomer means a polymer having a vinyl group (H ２ C=CH—) or vinylidene group (H ２The vinyl polymer preferably has a vinyl monomer-derived skeleton of 50 mol % or more, more preferably 70 mol % or more, even more preferably 90 mol % or more, and most preferably 100 mol % (i.e., composed only of vinyl monomer-derived skeletons) in the vinyl polymer skeleton. Furthermore, the vinyl monomer is not particularly limited, but examples thereof include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl ... (meth)acrylic monomers such as hydroxypropyl, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, ethylene oxide adducts of (meth)acrylic acid, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate;Examples of such monomers include aromatic vinyl monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and salts thereof; amide group-containing vinyl monomers such as (meth)acrylamide and N-methylol(meth)acrylamide; acrylonitrile monomers such as (meth)acrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; alkenes such as ethylene and propylene; vinyl chloride and vinylidene chloride;

[0031] In particular, the component (A-1) is preferably a homopolymer and / or copolymer primarily composed of at least one monomer selected from a (meth)acrylic monomer, an aromatic vinyl monomer, and an acrylonitrile monomer, more preferably a homopolymer and / or copolymer primarily composed of a (meth)acrylic monomer, and most preferably a homopolymer and / or copolymer of a (meth)acrylic monomer. In other words, a (meth)acrylic homopolymer and / or a (meth)acrylic copolymer is preferred. Note that the term "polymer primarily composed of monomer (X)" refers to a polymer obtained from a monomer component that contains 50 mol % or more, preferably 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more of monomer (X) relative to the total monomer component.

[0032] From the standpoint of workability, component (A-1) is preferably liquid at 25°C. Being liquid at 25°C means that the viscosity measured at 25°C using a cone-plate rotational viscometer is 1,000 Pa s or less. The viscosity of component (A-1) at 25°C is preferably 30 to 1,000 Pa s, more preferably 50 to 800 Pa s, and most preferably 75 to 600 Pa s. In this specification, viscosity is a value measured at 25°C using a cone-plate rotational viscometer.

[0033] The lower limit of the number average molecular weight (Mn) of the component (A-1) is preferably 500 or more, more preferably 3,000 or more, and particularly preferably 4,000 or more. The upper limit of the number average molecular weight (Mn) of the component (A-1) is preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 50,000 or less. That is, the number average molecular weight (Mn) of the component (A-1) is preferably 500 to 100,000, more preferably 3,000 to 80,000, and particularly preferably 4,000 to 50,000. When the number average molecular weight of the component (A-1) is 500 or more, the heat-dissipating resin composition is more effectively prevented from undergoing volumetric change upon exposure to high temperatures. On the other hand, when the number average molecular weight of the component (A-1) is 100,000 or less, the viscosity of the heat-dissipating resin composition can be better maintained, reducing the likelihood of stringiness when discharged from the nozzle of a dispenser, cartridge, or the like. In this specification, the "number average molecular weight (Mn)" is a value calculated by measurement using gel permeation chromatography (GPC), using tetrahydrofuran as a solvent and polystyrene as a standard.

[0034] The component (A-1) may be either a synthetic product or a commercially available product. The synthesis method for the component (A-1) is not particularly limited, but various polymerization reactions can be used. From the viewpoints of the versatility of monomers that can be used as raw materials and the ease of reaction control, it is preferable to synthesize the component (A-1) by a radical polymerization reaction. Furthermore, among radical polymerization reactions, controlled radical polymerization reactions are preferred, living radical polymerization reactions are more preferred, and atom transfer radical polymerization reactions are particularly preferred. Furthermore, known methods can be appropriately adopted as a method for introducing a crosslinkable silyl group into the main chain structure (vinyl skeleton or (meth)acryloyl skeleton). Methods for introducing a crosslinkable silyl group are described, for example, in JP-A-09-272714 (U.S. Patent Application Publication No. 2002 / 0177670) and JP-A-11-043512. Specific examples of commercially available products of the component (A-1) include XMAP (registered trademark) series SA100S, SA110S, SA120S, and OR100S manufactured by Kaneka Corporation. These may be used alone or in combination of two or more types.

[0035] The component (A-2) is an organic polymer, excluding the above-mentioned component (A-1), having two or more crosslinkable silyl groups in the molecule. There are no particular limitations on the number of crosslinkable silyl groups in the molecule, as long as there are two or more crosslinkable silyl groups in the molecule, and they may be present in either the side chains and / or terminals of the molecule. However, from the viewpoint of adhesive strength and curability, it is preferable that they are present at at least two terminals (for example, both terminals) of the main chain. There is no particular limitation on the upper limit of the number of crosslinkable silyl groups, but it may be 5 or less, and preferably 3 or less. The component (A-2) may be used alone, or two or more types may be used in combination.

[0036] The crosslinkable silyl group of component (A-2) is as described above. The crosslinkable silyl group of component (A-2) is preferably a group having two or three crosslinkable groups. In one embodiment, the crosslinkable silyl group of component (A-2) is preferably a group represented by the above chemical formulas (2) to (3). Furthermore, the crosslinkable silyl group of component (A-2) is preferably an alkoxysilyl group. Examples of the alkoxysilyl group include a methoxydimethylsilyl group, an ethoxydimethylsilyl group, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a trimethoxysilyl group, and a triethoxysilyl group. From the viewpoint of excellent volume change upon exposure to high temperatures, a dimethoxymethylsilyl group, a diethoxymethylsilyl group, a trimethoxysilyl group, and a triethoxysilyl group are preferred, and a dimethoxymethylsilyl group and / or a trimethoxysilyl group are most preferred.

[0037] The organic polymer constituting the main chain of component (A-2) is not particularly limited as long as it has a structure other than that of component (A-1). In other words, if it has a skeleton derived from a vinyl monomer, it is not classified as component (A-2). Specific examples include a polyoxyalkylene skeleton, a polyester skeleton, a polyamide skeleton, a polycarbonate skeleton, a polyisobutylene skeleton, etc., and a polyoxyalkylene skeleton is preferred because it is excellent at suppressing volume change when the heat-dissipating resin composition is exposed to high temperatures. Examples of polyoxyalkylene skeletons include, but are not limited to, a polyoxyethylene skeleton, a polyoxypropylene skeleton, a polyoxytriethylene skeleton, and a polyoxytetraethylene skeleton.

[0038] From the standpoint of workability, component (A-2) is preferably liquid at 25°C. Being liquid at 25°C means that the viscosity measured at 25°C using a cone-plate rotational viscometer is 1,000 Pa s or less. Specifically, the viscosity is preferably 0.1 to 100 Pa s, more preferably 0.3 to 80 Pa s, and most preferably 0.5 to 60 Pa s.

[0039] The component (A-2) may be either a synthetic product or a commercially available product. Specific examples of commercially available products include SAT010, SAX115, SAT030, SAT030, SAT200, SAT350, SAT400, SAX220, SAX510, SAX530, SAX575, SAX580, SAX710, SAX720, SAX725, SAX750, SAX770, S203, S303, S203H, S303H, S943S, S911S, MA440, and MA44. 7, MA451, MA903, MA903M, MA904, S943, MAX923, MAX951, SAX510, SAX520, SAX530, SAX580, EP100S, EP103S, EP303S, EP505S, etc. (manufactured by Kaneka Corporation), ES-S2410, ES-S2420, ES-S3430, ES-S3610, ES-S3630 (manufactured by AGC Inc.), etc. These may be used alone or in combination of two or more.

[0040] The content of component (A) relative to the entire heat-dissipating resin composition may be 1 to 45% by mass, preferably 1.5 to 30% by mass, and more preferably 2 to 10% by mass. The content of component (A) is the total content of all components (A).

[0041] The content of the component (A-1) relative to the entire heat-dissipating resin composition may be 0.5 to 44.5% by mass, preferably 0.5 to 29.5% by mass, and more preferably 1 to 9% by mass. When two or more types of component (A-1) are present, the content of the component (A-1) is the total content of these components.

[0042] The content of the component (A-2) relative to the entire heat-dissipating resin composition may be 0.5 to 44.5% by mass, preferably 0.5 to 29.5% by mass, and more preferably 1 to 9% by mass. When two or more types of component (A-2) are present, the content of the component (A-2) is the total content of these components.

[0043] <Component (B)> The component (B) that can be used in the present invention is a heat-dissipating filler. Examples of the component (B) include gold, silver, copper, alumina, zinc oxide, magnesium oxide, aluminum nitride, boron nitride, carbon, diamond, etc., but from the standpoints of thermal conductivity, insulation, and cost, it preferably contains at least one selected from the group consisting of alumina, aluminum nitride, and boron nitride, more preferably contains alumina, and most preferably contains only alumina. In addition, the heat-dissipating filler may be surface-treated with a fatty acid, resin acid, fatty acid ester, fatty acid metal salt, silane coupling agent, etc. These may be used alone, or two or more may be used in combination.

[0044] The shape of component (B) may be either spherical or irregular. The spherical heat-dissipating filler of the present invention does not only include perfectly spherical shapes, but also includes shapes such as nearly spherical shapes and shapes with elliptical cross sections. The irregular heat-dissipating filler of the present invention refers to heat-dissipating fillers other than spherical shapes, including heat-dissipating fillers with angular shapes. Examples of irregular heat-dissipating fillers include needle-shaped, fibrous, scaly, dendritic, and flat heat-dissipating fillers, as well as heat-dissipating fillers with irregular crushed shapes obtained by crushing block heat-dissipating fillers. These may be used alone or in combination of two or more.

[0045] Component (B) is preferably a powder from the viewpoint of excellent heat dissipation. The volume-based average particle size (50% average particle size) of component (B) is not particularly limited, but is preferably 0.01 to 150 μm, more preferably 0.1 to 100 μm, and most preferably 0.1 to 70 μm, from the viewpoint of obtaining a heat-dissipating resin composition with low viscosity before curing. In the present invention, the volume-based average particle size refers to the particle size at 50% of the cumulative particle size in the particle size distribution determined by a laser diffraction / scattering method. In one embodiment, component (B) preferably contains alumina powder.

[0046] From the viewpoint of reducing viscosity and improving thermal conductivity, the (B) component preferably contains two or more types of heat-dissipating fillers with different average particle sizes. Specifically, the average particle size of the heat-dissipating filler with a small average particle size is preferably 0.01 μm or more and less than 10 μm, more preferably 0.1 to 7 μm. The average particle size of the heat-dissipating filler with a large average particle size is preferably 10 to 150 μm, more preferably 15 to 100 μm, and most preferably 20 to 70 μm. In this specification, a heat-dissipating filler with an average particle size of 0.01 μm or more and less than 10 μm is referred to as the "(B-1) component," and a heat-dissipating filler with an average particle size of 10 to 150 μm is referred to as the "(B-2) component." That is, the (B) component preferably contains the (B-1) component and the (B-2) component. The (B-1) component may be used alone, or two or more types may be used in combination. The component (B-2) may be used alone or in combination of two or more. In one embodiment, the component (B-1) preferably contains two or more heat-dissipating fillers with different average particle sizes. In one embodiment, the component (B-2) preferably does not contain two or more heat-dissipating fillers with different average particle sizes, but uses only one type.

[0047] In one embodiment, the component (B) preferably contains a crushed component (B-1) and a spherical component (B-2). This configuration further improves the heat dissipation properties of the heat-dissipating resin composition. The component (B) preferably contains alumina, which is the crushed component (B-1), and alumina, which is the spherical component (B-2).

[0048] In one embodiment, the content of the (B-2) component is 10 to 800 parts by mass, more preferably 20 to 500 parts by mass, and most preferably 50 to 300 parts by mass, per 100 parts by mass of the (B-1) component. When the content of the (B-2) component is within the range of 10 to 800 parts by mass per 100 parts by mass of the (B-1) component, the thermal conductivity is even more excellent. In one embodiment, the content of the (B-2) component is preferably more than 100 parts by mass and not more than 800 parts by mass, more preferably more than 100 parts by mass and not more than 200 parts by mass, and particularly preferably more than 100 parts by mass and not more than 150 parts by mass, per 100 parts by mass of the (B-1) component. When two or more types of the (B-1) component are contained, the content of the (B-1) component is the total value of these. Similarly, when two or more types of the (B-2) component are contained, the content of the (B-2) component is the total value of these.

[0049] When component (B) contains two or more types of heat-dissipating fillers with different average particle sizes, the volumetric particle size distribution of component (B) may have two or more peaks. When component (B) contains components (B-1) and (B-2), the volumetric particle size distribution of component (B) may have at least one peak in each of the particle size ranges of 0.01 μm or more and less than 10 μm and the particle size range of 10 μm or more and 150 μm or less. In one embodiment, the volumetric particle size distribution of component (B) may have two or more peaks in the particle size range of 0.01 μm or more and less than 10 μm (preferably, 0.1 μm or more and 7 μm or less), and preferably has two or more peaks in the particle size range of 0.01 μm or more and less than 10 μm (preferably, 0.1 μm or more and 7 μm or less), and only one peak in the particle size range of 10 μm or more and 150 μm or less (preferably, 20 μm or more and 70 μm or less). In this specification, "volumetric particle size distribution" means a particle size distribution determined by laser diffraction / scattering.

[0050] The content of component (B) relative to the entire heat-dissipating resin composition is preferably 55 to 99% by mass, more preferably 60 to 98% by mass, and most preferably 70 to 95% by mass. Furthermore, the content of component (B) is preferably 100 to 5,000 parts by mass, more preferably 300 to 4,000 parts by mass, particularly preferably 500 to 3,000 parts by mass, and most preferably 1,000 to 3,000 parts by mass, per 100 parts by mass of component (A). By being in the above range, a cured product with excellent thermal conductivity can be obtained. When two or more types of component (B) are contained, the content of component (B) is the total value of these.

[0051] The content of component (B-1) in the entire heat-dissipating resin composition is preferably 15 to 90 mass%, more preferably 20 to 70 mass%, and most preferably 30 to 60 mass%. The content of component (B-1) is preferably 100 to 2,000 mass parts, more preferably 300 to 1,500 mass parts, and most preferably 500 to 1,000 mass parts per 100 mass parts of component (A).

[0052] The content of component (B-2) relative to the total heat-dissipating resin composition is preferably 20 to 90 mass%, more preferably 35 to 80 mass%, and most preferably 45 to 70 mass%. The content of component (B-2) relative to 100 mass parts of component (A) is preferably 100 to 3,000 mass parts, more preferably 500 to 3,500 mass parts, and most preferably 750 to 2,000 mass parts.

[0053] Component (C) that can be used in the present invention is a curing catalyst containing a zinc compound. Examples of the zinc compound of component (C) include zinc salts and zinc complexes, such as, but not limited to, zinc octoate, zinc naphthenate, zinc hexacyanocobaltate complex, 1-methylimidazole-bis(2-hexanoate) zinc complex, and alkylamine zinc complex. These may be used alone or in combination of two or more. From the viewpoint of excellent curability, it is preferable to include an amine compound in addition to the zinc compound. Note that, in this specification, the amine in a zinc complex containing an amine as a ligand is treated as part of the zinc compound, not as an amine compound. Amines that do not contain zinc are treated as amine compounds.

[0054] Examples of the amine compound include alkylamine compounds, alkyldiamine compounds, alkyltriamine compounds, arylamine compounds, aryldiamine compounds, and aryltriamine compounds, and among these, alkylamine compounds are preferred in terms of excellent curability, but are not limited thereto. The alkylamine compound may be the same as the one coordinated to the zinc compound.

[0055] When a zinc compound and an amine compound are used in combination, the respective contents (mass ratio) are preferably 1:99 to 99:1, more preferably 5:95 to 50:50, and most preferably 10:90 to 30:70. A ratio in the range of 1:99 to 99:1 provides excellent curability and excellent suppression of volume change of the cured product when exposed to high temperatures.

[0056] The content of the zinc compound relative to the entire component (C) is, for example, 5% by mass to 30% by mass, preferably 8% by mass to 20% by mass. The content of the zinc compound relative to the total amount of the zinc compound and the amine compound is, for example, 5% by mass to 30% by mass, preferably 8% by mass to 20% by mass. The content of the zinc compound relative to the entire heat-dissipating resin composition is, for example, 0.001% by mass to 2% by mass, preferably 0.002% by mass to 0.5% by mass. The content of the zinc compound relative to 100 parts by mass of component (A) is, for example, 0.01 parts by mass to 5 parts by mass, preferably 0.05 parts by mass to 1 part by mass.

[0057] The content of the amine compound relative to the entire component (C) is, for example, 70% to 95% by mass, preferably 80% to 92% by mass. The content of the amine compound relative to the total amount of the zinc compound and the amine compound is, for example, 70% to 95% by mass, preferably 80% to 92% by mass. The content of the amine compound relative to the entire heat-dissipating resin composition is, for example, 0.005% to 3% by mass, preferably 0.01% to 0.1% by mass. The content of the amine compound is, for example, 0.1 parts by mass to 10 parts by mass, preferably 0.3 parts by mass to 5 parts by mass, relative to 100 parts by mass of component (A).

[0058] The content of component (C) relative to the entire heat-dissipating resin composition is, for example, 0.005% by mass to 10% by mass, preferably 0.01% by mass to 5% by mass, and more preferably 0.03% by mass to 0.5% by mass. Furthermore, the content of component (C) relative to 100 parts by mass of component (A) is preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and most preferably 0.5 to 5 parts by mass. A content of 0.05 parts by mass or more provides excellent curability, while a content of 20 parts by mass or less provides excellent suppression of volume change of the cured product when exposed to high temperatures. When two or more types of component (C) are contained, the content of component (C) is the total value of these.

[0059] Commercially available products of the component (C) include K-KAT670, K-KATXK-648, and K-KATXK-614 (manufactured by KING INDUSTRIES), but are not limited to these.

[0060] The heat dissipating resin composition may contain the components in the following mass ratios: (A) component: 1 mass % to 35 mass %, (B) component: 55 to 98.995 mass %, and (C) component: 0.005 mass % to 10 mass %.

[0061] In addition to the above components, various additives may be added as optional components to the heat-dissipating resin composition of the present invention, as needed, within the range that does not impair the effects of the present invention. Examples of additives include adhesion promoters, storage stabilizers, plasticizers, fillers (excluding component (B)), tackifiers, organic or inorganic pigments, rust inhibitors, antifoaming agents, dispersants, surfactants, antioxidants, light stabilizers, viscoelasticity modifiers, and thickeners.

[0062] The heat-dissipating resin composition of the present invention preferably contains an adhesion promoter. By including an adhesion promoter, a cured product with excellent adhesive strength can be obtained. Examples of adhesion promoters include silane compounds having a crosslinkable silyl group as well as a reactive functional group other than the crosslinkable silyl group. Note that the crosslinkable silyl group-containing organic polymer (dimer or higher polymer) described in the section on component (A) is considered to be included in the above component (A) and is not treated as an adhesion promoter. Furthermore, a (meth)acrylic monomer (monomer) having a crosslinkable silyl group is treated as an adhesion promoter.

[0063] The crosslinkable silyl group that can be contained in the adhesion promoter can be the same as that described for component (A). In one embodiment, the crosslinkable silyl group that can be contained in the adhesion promoter is preferably a crosslinkable silyl group that contains an alkoxy group as the crosslinkable group, because this provides excellent adhesive strength.

[0064] Examples of reactive functional groups other than the crosslinkable silyl group include epoxy groups, vinyl groups, (meth)acrylic groups, amino groups (excluding those bonded to silicon atoms), mercapto groups, and carboxyl groups.

[0065] In one embodiment, the adhesion promoter may be a compound represented by the following chemical formula (4):

[0066]

[0067] In the above chemical formula (4), R ４１ ~R ４３ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and R ４１ ~R ４３ at least one of L is an alkoxy group having 1 to 6 carbon atoms; ４１ is a single bond or an alkylene group having 1 to 6 carbon atoms, R ４４ represents an epoxy group, an epoxycycloalkyl group having 3 to 6 carbon atoms, a carboxyl group, an amino group (-NH ２ ), an arylamino group having 6 to 12 carbon atoms, a mercapto group (—SH), a group represented by the following chemical formula (4-a), and a group represented by the following chemical formula (4-b):

[0068]

[0069] In the above chemical formula (4-a) and chemical formula (4-b), L ４１ is an alkylene group having 1 to 6 carbon atoms, * (asterisk) is the bonding point to another atom, R ４４ is an amino group (-NH ２ ), an arylamino group having 6 to 12 carbon atoms, a mercapto group (—SH), or a group represented by the above chemical formula (4-b), when L ４１ is an alkylene group having 1 to 6 carbon atoms.

[0070] In addition, in the above chemical formula (4), L ４１ is preferably an alkylene group having 2 to 6 carbon atoms, and more preferably an alkylene group having 2 to 4 carbon atoms. ４４ is an amino group (-NH ２ ), an arylamino group having 6 to 12 carbon atoms, or a group represented by the above chemical formula (4-b), and ２ ) or a group represented by the above chemical formula (4-b), and an amino group (—NH２ ) is particularly preferred.

[0071] The adhesion promoter is not particularly limited, and examples thereof include epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; glycidyl group-containing silane coupling agents such as 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane; vinyltris(2-methoxyethoxy)silane, vinyltriethoxysilane, and vinyltrimethoxysilane. (meth)acrylic group-containing silane coupling agents such as (3-(meth)acryloyloxypropyl)trimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane; and mercapto group-containing silane coupling agents such as (3-mercaptopropyl)trimethoxysilane. These may be used alone or in combination of two or more.

[0072] The adhesion promoter preferably contains an amino group-containing silane coupling agent, and more preferably contains 3-aminopropyltrimethoxysilane and / or 3-aminopropyltriethoxysilane, in that a cured product with excellent adhesive strength can be obtained.

[0073] The content of the adhesion promoter relative to the entire heat-dissipating resin composition is preferably 0.01 to 0.5% by mass, more preferably 0.05 to 0.2% by mass. The content of the adhesion promoter is not particularly limited, but is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and most preferably 0.5 to 5 parts by mass, per 100 parts by mass of component (A). An amount of 0.01 part by mass or more provides excellent adhesive strength for the cured product, while an amount of 20 parts by mass or less provides excellent suppression of volume change when the cured product is exposed to high temperatures. When two or more adhesion promoters are used, the content of the adhesion promoters is the combined value of these.

[0074] The adhesion promoter may be either a synthetic product or a commercially available product. Specific examples of commercially available products include KBM-903, KBE-903, etc. (manufactured by Shin-Etsu Chemical Co., Ltd.), Z-6610 Silane, Z-6011 Silane, etc. (manufactured by Dow-Toray Industries, Inc.).

[0075] The heat-dissipating resin composition of the present invention may contain a storage stabilizer. Examples of the storage stabilizer include silane compounds that do not have reactive functional groups other than alkoxysilyl groups, excluding the component (A) and adhesion promoters. Examples of silane compounds that do not have reactive functional groups other than alkoxysilyl groups include alkylsilane compounds such as methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, n-propyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltriethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, and decyltriethoxysilane. These may be used alone or in combination of two or more, but in terms of excellent storage stability, it is preferable to contain methyltrimethoxysilane and / or diphenyldimethoxysilane, and it is more preferable to contain methyltrimethoxysilane and diphenyldimethoxysilane. When both methyltrimethoxysilane and diphenyldimethoxysilane are contained, the mass ratio of each is preferably 99:1 to 50:50, more preferably 95:5 to 60:40, and most preferably 90:10 to 70:30.

[0076] The content of the storage stabilizer relative to the entire heat-dissipating resin composition is preferably 0.05 to 5% by mass, more preferably 0.1 to 1% by mass. The content of the storage stabilizer is not particularly limited, but is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, even more preferably 5 to 25 parts by mass, and most preferably 10 to 20 parts by mass, relative to 100 parts by mass of the component (A). When two or more types of storage stabilizers are contained, the content of the storage stabilizers is the total value of these.

[0077] The heat-dissipating resin composition of the present invention may contain a plasticizer. The inclusion of a plasticizer results in excellent storage stability and suppression of volume change when exposed to high temperatures. The plasticizer is preferably liquid at 25°C and is compatible with component (A). Specific examples include, but are not limited to, propylene carbonate, DOS (di-2-ethylhexyl sebacate), DOP (dioctyl phthalate), DINP (diisononyl phthalate), DIDP (diisodecyl phthalate), DBP (dibutyl phthalate), DMS (dimethyl sebacate), DOA (dioctyl adipate), DINA (diisononyl adipate), TCP (tricresyl phosphate), DMM (dimethyl maleate), and (meth)acrylic polymers that are liquid at 25°C. The plasticizer may be, for example, a dicarboxylic acid ester compound. These may be used alone or in combination of two or more. The content of the plasticizer relative to the entire heat-dissipating resin composition is preferably 0.01 to 3 mass%, more preferably 0.05 to 2 mass%. The plasticizer is preferably contained in an amount of 0.5 to 10 parts by mass per 100 parts by mass of component (A). When two or more plasticizers are contained, the content of the plasticizers is the total value of these.

[0078] The heat-dissipating resin composition of the present invention preferably does not substantially contain a polymeric compound having a siloxane structure as its main chain skeleton. If the heat-dissipating resin composition contains a polymeric compound having a siloxane structure as its main chain skeleton, there is a concern that contact failure of electronic components may occur due to the volatilization of low-molecular-weight siloxane components or cyclic siloxane components. "Substantially free" means that the polymeric compound is not intentionally contained as a component of the heat-dissipating resin composition, and does not exclude, for example, unintentional inclusion due to unintentional inclusion or insufficient removal. In one embodiment, the content of the polymeric compound having a siloxane structure as its main chain skeleton is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less, relative to the entire heat-dissipating resin composition. If the content is 1% by mass or less, there is no concern about contact failure of electronic components. In this specification, "polymeric compound" refers to a compound having a molecular weight of 500 or more.

[0079] The viscosity of the heat-dissipating composition of the present invention is, for example, 0.01 to 800 Pa·s, preferably 1 to 600 Pa·s, and more preferably 100 to 500 Pa·s. Within the above range, the heat-dissipating composition is even easier to handle. In this specification, the viscosity is measured at 25°C using a cone-plate viscometer.

[0080] The method for producing the heat-dissipating resin composition according to the present invention is not particularly limited, and conventionally known methods can be appropriately employed. For example, predetermined amounts of components (A), (B), (C), and any optional components are weighed and added to a stirring vessel sequentially or simultaneously in any order, and then mixed using a mixing means such as a planetary mixer, preferably while vacuum degassing. Preferably, component (C) is added last. Adding component (C) last can prevent the curing reaction from proceeding at an undesired stage.

[0081] Specifically, for example, the component (A) and the optional components (e.g., adhesion promoter, storage stabilizer, and plasticizer) are first weighed into a stirring vessel and stirred at room temperature for 10 minutes to 3 hours, preferably 30 minutes to 2 hours, while being vacuum degassed. Then, the component (B) is added to the mixture obtained by stirring, and the mixture is further stirred at room temperature for 1 minute to 3 hours, preferably 30 minutes to 2 hours, while being vacuum degassed. Next, the component (C) is added to the mixture obtained, and the mixture is further stirred at room temperature for 1 minute to 2 hours, preferably 5 minutes to 1 hour, while being vacuum degassed, to obtain a moisture-curable resin composition.

[0082] In one embodiment, the method for producing a heat-dissipating resin composition according to the present invention preferably comprises sequentially or simultaneously mixing the (B-1) and (B-2) components with either the (A) and (C) components, or with a mixture containing at least one of the (A) and (C) components. In a preferred embodiment, the method comprises sequentially or simultaneously mixing the (B-1) and (B-2) components with a mixture of the (A) component and the optional components (e.g., an adhesion promoter, a storage stabilizer, and a plasticizer). In a further preferred embodiment, the method for producing a heat-dissipating resin composition according to the present invention comprises mixing the (C) component with a mixture of the (A) component, the optional components (e.g., an adhesion promoter, a storage stabilizer, and a plasticizer), and the (B-1) and (B-2) components.

[0083] Another aspect of the present invention is a cured product obtained by curing the heat-dissipating resin composition.

[0084] In one embodiment, the cured product has a volume change rate of 0% or more and 2.0% or less between the cured product immediately after curing (a cured product that has not been exposed to a temperature of 30°C or higher after curing) and the cured product after a load test. The load test is performed by leaving the cured product immediately after curing at a temperature of 120°C for 240 hours. Cured products with a volume change rate within the above range have particularly excellent heat resistance. The volume change rate before and after the load test is measured and calculated by the method described in the examples below. Therefore, the present invention also provides a heat-dissipating resin composition that, when cured, results in a volume change rate within the above range for the cured product.

[0085] In one embodiment, the cured product preferably has adhesive properties because its heat dissipation properties are further improved by its close contact with the adherend. The adhesive strength of the cured product is evaluated, for example, as shear bond strength to aluminum, and the shear bond strength to aluminum is preferably 1.0 MPa or more, particularly preferably 1.5 MPa or more. In this specification, the shear bond strength to aluminum is measured by the method described in the Examples below. Therefore, the present invention also provides a heat-dissipating resin composition that, when cured, results in a shear bond strength to aluminum of the cured product within the above range.

[0086] In one embodiment, the cured product may have excellent heat dissipation properties. Since it is expected that the heat dissipation properties will not change much before and after curing, the heat dissipation properties of the cured product can be evaluated from the heat dissipation properties of the heat dissipating resin composition before curing. The heat dissipation properties of the heat dissipating resin composition before curing are preferably, for example, 3.5 W / (m·k) or more. The heat dissipation properties of the heat dissipating resin composition before curing are measured by the method described in the examples below. Therefore, the present invention also provides a heat dissipating resin composition having heat dissipation properties within the above range.

[0087] The method for curing the heat-dissipating resin composition according to the present invention is not particularly limited, and known methods can be used. One example is a method in which the heat-dissipating resin composition according to the present invention is applied to an adherend, a substrate, or the like, and then cured at room temperature. In this case, the method for applying the heat-dissipating resin composition is not particularly limited, and known methods can be appropriately adopted. For example, methods such as dispensing using an automatic coater, spraying, inkjet printing, screen printing, gravure printing, dipping, and spin coating can be used. Furthermore, the thickness of the coating film is not particularly limited, and can be adjusted appropriately depending on the application.

[0088] The curing temperature of the heat-dissipating resin composition of the present invention is not particularly limited, but is preferably 10 to 50°C, and more preferably 15 to 30°C. The relative humidity during curing is preferably 40% RH or higher. The upper limit of the relative humidity is not particularly limited, but is, for example, 55% RH or lower. Furthermore, the curing time is preferably 1 hour or longer but less than 2 weeks, and more preferably 3 to 10 days.

[0089] The heat-dissipating resin composition of the present invention can be a one-component type or a two-component type as needed. The heat-dissipating resin composition of the present invention is most suitable for use in areas requiring heat dissipation, but can also be used as a sealant, coating agent, potting agent, etc. as needed. The heat-dissipating resin composition of the present invention can be used for various electrical and electronic applications, buildings, automobiles, civil engineering, etc. Since the composition can form a cured product with excellent heat dissipation properties and excellent suppression of volume change upon exposure to high temperatures, and has an extremely low content of low-molecular-weight siloxanes, it is particularly suitable for use in electrical and electronic components and automotive electrical components, and is particularly suitable for heat dissipation applications in batteries.

[0090] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples (hereinafter, the heat-dissipating resin composition may also be simply referred to as the composition). Unless otherwise specified, tests were conducted at room temperature (23°C) and in a 50% RH environment.

[0091] Examples 1 to 5, Comparative Examples 1 to 5 To prepare the compositions of Examples 1 to 5 and Comparative Examples 1 to 5, the following components were prepared.

[0092] Component (A): Crosslinkable silyl group-containing organic polymer Component (A-1): Vinyl polymer having one or more crosslinkable silyl groups in the molecule XMAP SA120S (acrylic copolymer having dimethoxymethylsilyl groups at both ends, viscosity (25°C) 85 Pa·s, number average molecular weight 5,000 to 40,000, manufactured by Kaneka Corporation) XMAP SA110S (acrylic copolymer having dimethoxymethylsilyl groups at both ends, viscosity (25°C) 500 Pa·s, number average molecular weight 5,000 to 40,000, manufactured by Kaneka Corporation) Component (A-2): Organic polymer having two or more crosslinkable silyl groups in the molecule (excluding component (A-1)) Kaneka Silyl SAT115 (polyoxyalkylene having dimethoxymethylsilyl groups at both ends, viscosity (25°C) 0.7 Pa·s, manufactured by Kaneka Corporation) Kaneka Silyl SAX575 (polyoxyalkylene having trimethoxysilyl groups at both ends, viscosity (25°C) 50 Pa·s, manufactured by Kaneka Corporation) Component (A'): a crosslinkable silyl group-containing organic polymer other than components (A-1) and (A-2) Kaneka Silyl SAT145 (polyoxyalkylene having a dimethoxymethylsilyl group at one end, viscosity (25°C) 2.5 Pa·s, manufactured by Kaneka Corporation) Component (B): a heat-dissipating filler Component (B-1): a heat-dissipating filler having an average particle size of 0.01 μm or more and less than 10 μm LS-710C (alumina powder, crushed shape, average particle size: 0.5 μm, manufactured by Nippon Light Metal Co., Ltd.) AX3-32 (alumina powder, spherical, average particle size: 3.5 μm, manufactured by Nippon Steel Chemical & Material Co., Ltd.) Component (B-2): Heat-dissipating filler having an average particle size of 10 to 150 μm AX35-125 (alumina powder, spherical, average particle size: 35 μm, manufactured by Nippon Steel Chemical & Material Co., Ltd.) Component (C): Curing catalyst containing a zinc compound K-KAT670 (zinc compound: 2 mass%, alkylamine: 15 mass%, other component (plasticizer): 83 mass%, manufactured by King Industries) Component (C'): Curing catalyst other than component (C) TC-750 (titanium diisopropoxybis(ethylacetoacetate), manufactured by Matsumoto Fine Chemical Co., Ltd.) Optional component KBM-903 (silane coupling agent, 3-aminopropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)KBM-13 (storage stabilizer, methyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) KBM-202SS (storage stabilizer, diphenyldimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) DMS (plasticizer, dimethyl sebacate, manufactured by Toyokuni Oil Mills Co., Ltd.) Compositions of Examples 1 to 5 and Comparative Examples 1 to 5 were prepared. Specifically, first, component (A) (or component (A')) and optional components were weighed and placed in a stirring vessel, and then stirred for 1 hour while being degassed under vacuum. Thereafter, component (B) was weighed and placed in the stirring vessel, and then stirred for 1 hour while being degassed under vacuum. Finally, component (C) (or component (C')) was weighed and stirred for 30 minutes while being degassed under vacuum to obtain a composition. Detailed mass ratios of the components are shown in Table 1, and all values ​​are expressed in parts by mass.

[0093] <Adhesion Strength Measurement> Preparation of Test Pieces A heat-dissipating resin composition of an example or comparative example in Table 1 was applied to an aluminum (A1050P) test piece measuring 25 mm wide, 100 mm long, and 1 mm thick. Then, another aluminum (A1050P) test piece was attached and fixed so that the overlapping surface was 25 mm, 10 mm, and a clearance of 1 mm was maintained. The test piece was then left to stand for 7 days in an environment of 23°C and 50% RH to cure, and used as a test piece.

[0094] Measurement of Adhesion Strength: The shear adhesive strength of the test specimens was measured at 25°C using a universal tensile tester (tensile speed 50 mm / min) in accordance with JIS K 6850:1999. The value at the maximum shear adhesive strength is shown in Table 1 as adhesive strength [MPa]. In the present invention, the shear adhesive strength to aluminum is preferably 1.0 MPa or more. In addition, the composition of Comparative Example 5 had a high viscosity in this measurement, and therefore test specimens could not be prepared, and is therefore indicated as "-" in Table 1.

[0095] <Volume Change Measurement> Each of the compositions of Examples 1 to 5 and Comparative Examples 1 and 2 was filled into a mold to a width of 150 mm, length of 100 mm, and thickness of 2 mm. Cured products were then prepared by leaving the mold at 23°C and 50% RH for 7 days. The resulting cured products were cut into 20 mm diameter x 2 mm thick specimens. The specimens were weighed in air (W1) and in water (W2). A load test was then performed on the specimens. Specifically, the specimens were heated in a constant temperature bath at 120°C for 240 hours. The specimens were removed from the constant temperature bath and allowed to stand at room temperature until they reached room temperature. Then, the specimens were weighed in air (W3) and in water (W4). The volume change rate (%), expressed by the following formula 1, was calculated using the obtained weights. The test was performed twice for each composition, and the average values ​​are shown in Table 1. Detailed test methods were performed according to JIS K 6258:2016. In the present invention, the volume change rate is preferably 2.0% or less, more preferably 1.5% or less, and most preferably 1.0% or less, in order to prevent changes in properties such as heat dissipation, adhesive strength, and sealing ability. In Table 1, values ​​for which no measurement was performed are indicated by "-".

[0096]

[0097] <Heat Dissipation Measurement> The heat dissipation properties of the compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were measured by plotting the thermal conductivity [λ(W / (m·K))] of the control substance (reference) on the X axis and the "deviation" shown by the following formula on the Y axis. The value on the X axis when the Y axis value was 0 was calculated using the approximation formula, and the value on the X axis at that time was taken as the heat dissipation property [W / (m·K)]. The test method involved applying the composition to each of the following references to a thickness of 500 μm, and then contacting the composition with a measuring device (QTM-500, product of Kyoto Electronics Manufacturing Co., Ltd.) so as to sandwich the composition between them. Measurements were then performed on each uncured composition. The deviation was calculated using the thermal conductivity obtained in the above measurement and the thermal conductivity of each reference used, and the measured values ​​were plotted. The value on the X axis when the Y axis value was 0 was determined. In the present invention, heat dissipation properties of 3.5 W / (m·K) or more are preferred. In Table 1, values ​​for which no measurement was performed are indicated by "-".

[0098]

[0099]

[0100] Examples 1 to 5, which are compositions containing components (A) to (C), were confirmed to have excellent adhesive strength and heat dissipation, and also excellent durability at high temperatures due to a small volume change rate. On the other hand, Comparative Example 1, which is a composition containing only component (A-2) of the (A) components but not component (A-1), was confirmed to have a high volume change rate and poor durability at high temperatures. Comparative Example 2, which is a composition containing component (A-2) of the (A) components, was also confirmed to have a high volume change rate and poor durability at high temperatures. Furthermore, Comparative Example 3, which is a composition not containing component (A) but instead containing component (A'), was confirmed to have poor adhesive strength. Comparative Example 4, which is a composition containing component (C') instead of component (C), was also confirmed to have poor adhesive strength. Comparative Example 5, which is a composition containing neither component (A-2) nor component (A'), was confirmed to have poor workability, as test specimens could not be prepared due to its extremely high viscosity.

[0101] The heat-dissipating resin composition of the present invention has excellent adhesive strength and heat dissipation properties, and is capable of reducing the rate of volume change when exposed to high temperatures. Therefore, it is extremely useful in a variety of applications, such as heat dissipation and sealing, for electronic substrates, lighting such as LEDs for electronic devices such as mobile phones and personal computers, optical pickup modules, camera modules, sensing devices, power semiconductors, inverters for HEVs, FCVs, and EVs, converters for HEVs, FCVs, and EVs, battery packs, ECU parts for HEVs, FCVs, and EVs, and automobile batteries.

[0102] This application is based on Japanese Patent Application No. 2024-027063, filed on February 27, 2024, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A heat-dissipating resin composition comprising the following components (A) to (C), wherein the component (A) comprises the following components (A-1) and (A-2): Component (A): a crosslinkable silyl group-containing organic polymer; Component (A-1): a vinyl polymer having one or more crosslinkable silyl groups in the molecule; Component (A-2): an organic polymer having two or more crosslinkable silyl groups in the molecule (excluding component (A-1)); Component (B): a heat-dissipating filler; and Component (C): a curing catalyst containing a zinc compound.

2. The heat-dissipating resin composition according to claim 1, wherein the component (A-2) is an organic polymer having a polyoxyalkylene skeleton.

3. The heat-dissipating resin composition according to claim 1 or 2, wherein the component (A-1) and the component (A-2) have crosslinkable silyl groups at at least two ends of the main chain skeleton.

4. The heat-dissipating resin composition according to claim 1 or 2, wherein component (B) contains alumina powder.

5. The heat-dissipating resin composition according to claim 1 or 2, wherein the component (B) comprises the following components (B-1) and (B-2): component (B-1): a heat-dissipating filler having an average particle size of 0.01 μm or more and less than 10 μm; and component (B-2): a heat-dissipating filler having an average particle size of 10 μm or more and 150 μm or less.

6. The heat dissipating resin composition according to claim 1 or 2, wherein the volumetric particle size distribution of component (B) has two or three or more peaks, and at least one peak appears in each of a region where the particle size is 0.01 μm or more and less than 10 μm, and a region where the particle size is 10 μm or more and 150 μm or less.

7. The heat-dissipating resin composition according to claim 1 or 2, wherein the component (A) consists solely of the component (A-1) and the component (A-2).

8. The heat dissipating resin composition according to claim 7, wherein the mass ratio of the component (A-1) to the component (A-2) (total mass of the component (A-1):total mass of the component (A-2)) is 80:20 to 20:

80.

9. The heat-dissipating resin composition according to claim 1 or 2, further comprising an amino group-containing silane coupling agent.

10. A heat-dissipating resin composition according to claim 1 or 2, wherein the volume change rate of a cured product obtained by curing the heat-dissipating resin composition before and after a load test is 0% or more and 2.0% or less, and the load test is carried out by leaving the cured product at a temperature of 120°C for 240 hours.

11. A cured product obtained by curing the heat-dissipating resin composition according to claim 1 or 2.

12. A method for producing a heat-dissipating resin composition according to claim 1 or 2, comprising sequentially or simultaneously mixing the following components (B-1) and (B-2) with either one of the components (A) and (C), or with a mixture containing at least one of the components (A) and (C): component (B-1): a heat-dissipating filler having an average particle size of 0.01 μm or more and less than 10 μm; component (B-2): a heat-dissipating filler having an average particle size of 10 μm or more and 150 μm or less.

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