Resin composition, heat dissipation device, and electronic device

Abstract

A resin composition including a urethane (meth)acrylate, a heat-conductive filler, and a crosslinking agent, wherein the urethane (meth)acrylate is a reaction product of: a hydroxyl-group-containing, high-molecular-weight body having a number-average molecular weight of more than 5,000 and being at least one selected from the group consisting of amino alcohols having one or more hydroxyl groups and one or more amino groups, and polyols having two or more hydroxyl groups; a polyisocyanate having two or more isocyanate groups; and a (meth)acrylate having one or more hydroxyl groups.

Description

Resin composition, heat dissipation device, and electronic device

[0001] The present invention relates to a resin composition, a heat dissipation device, and an electronic device, and in particular to a resin composition, a heat dissipation device including an adhesive layer formed from a cured product of the resin composition, and an electronic device including an insulating layer formed from a cured product of the resin composition.

[0002] Electronic devices are used in a variety of industrial fields, and various proposals have been made regarding further improving the functionality of materials for electronic devices. For example, Patent Document 1 discloses a resin composition that contains an amorphous resin component, an epoxy resin that is liquid at 25°C, a thermally conductive filler with a thermal conductivity of 20 W / m·K or more, and rubber particles, and that can form an insulating layer that has excellent thermal conductivity and adhesive strength to a metal layer at low temperatures.

[0003] Japanese Patent Application Laid-Open No. 2019-38969

[0004] However, a resin composition that maintains the basic properties of heat dissipation paste, such as fluidity and heat dissipation, while having sufficient strength after curing and being easy to handle, such as being less likely to crack, has not yet been obtained, and there has been a strong demand for the development of such a resin composition.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a resin composition that maintains the fluidity and heat dissipation properties that are the basic properties of a heat dissipation paste while exhibiting good handleability after curing, a heat dissipation device including an adhesive layer formed from the cured product of the resin composition, and an electronic device including an insulating layer formed from the cured product of the resin composition.

[0006] The present invention is based on the discovery that by including a urethane (meth)acrylate of a specific structure prepared using a hydroxyl group-containing polymer (number average molecular weight exceeding 5000) (hereinafter also referred to as component (A)), it is possible to obtain a resin composition that has good handleability after curing while maintaining the basic properties of heat dissipation paste, namely, fluidity and heat dissipation.

[0007] The present invention provides the following means. [1] A resin composition comprising a urethane (meth)acrylate, a thermally conductive filler, and a crosslinking agent, wherein the urethane (meth)acrylate is at least one selected from the group consisting of amino alcohols having one or more hydroxyl groups and one or more amino groups, and polyols having two or more hydroxyl groups, and is a reaction product of a hydroxyl group-containing polymer having a number average molecular weight of more than 5,000, a polyisocyanate having two or more isocyanate groups, and a (meth)acrylate having one or more hydroxyl groups. [2] The resin composition according to [1] above, wherein the thermally conductive filler is at least one selected from the group consisting of boron nitride, aluminum oxide, silicon carbide, and aluminum. [3] The resin composition according to [1] or [2] above, wherein the content of the urethane (meth)acrylate is 7.0 to 33.0 mass% based on the total mass of solids in the resin composition. [4] The resin composition according to any one of [1] to [3] above, wherein the content of the thermally conductive filler is 50.0 to 92.0 mass% based on the total solid mass of the resin composition. [5] The resin composition according to any one of [1] to [4] above, wherein the content of the crosslinking agent is 1.0 to 17.0 mass% based on the total solid mass of the resin composition. [6] The resin composition according to any one of [1] to [5] above, wherein the cured product of the resin composition has a thermal conductivity of 5 W / m K or more. [7] A heat dissipation device according to any one of [1] to [6] above, comprising an adhesive layer formed from a cured product of the resin composition. [8] An electronic device according to any one of [1] to [6] above, comprising an insulating layer formed from a cured product of the resin composition.

[0008] According to the present invention, there are provided a resin composition that maintains the basic properties of heat dissipation paste, namely fluidity and heat dissipation, while exhibiting good handleability after curing, a heat dissipation device including an adhesive layer formed from the cured product of the resin composition, and an electronic device including an insulating layer formed from the cured product of the resin composition.

[0009] The definitions and meanings of terms and notations used in this specification are shown below. In this specification, the number average molecular weight (Mn) is the polystyrene-equivalent molecular weight determined by gel permeation chromatography (GPC) based on a calibration curve prepared using a standard polystyrene sample. In this specification, the term "(meth)acrylic" refers to "methacrylic" or "acrylic". Similarly, the term "(meth)acrylate" refers to "methacrylate" or "acrylate". In this specification, the term "solid content" refers to the non-volatile content excluding volatile substances such as solvents, and indicates the components that remain without volatilization when the resin composition is dried, and includes those that are liquid, syrup-like, and wax-like at room temperature.

[0010] [Resin Composition] The resin composition according to an embodiment of the present invention (hereinafter referred to as the present embodiment) contains a urethane (meth)acrylate, a thermally conductive filler, and a crosslinking agent, and further contains other components as necessary.

[0011] The resin composition of this embodiment is non-stretchable. Here, "non-stretchable" means that the resin composition does not elastically recover after being stretched 11 times to an elongation of 80%.

[0012] The resin composition of this embodiment may be in the form of a liquid, paste, film, or molded article. The resin composition includes various pastes such as adhesives, paints, and conductive pastes, as well as products or uses before the final product, such as protective films, molding materials, resin modifiers, and additives. The resin composition may also be a component itself, such as a layer, film, or molded product. The use of the resin composition is not limited, but it is suitable as a resin composition for SiC MOSFETs. The term "SiC MOSFET" refers to a MOSFET made of SiC (silicon carbide) that has high breakdown voltage and low ON resistance.

[0013] (Urethane (meth)acrylate) The urethane (meth)acrylate is a reaction product of the above-mentioned hydroxyl group-containing polymer (hereinafter also referred to as “component (A)”), the above-mentioned polyisocyanate (hereinafter also referred to as “component (B)”), and a (meth)acrylate (hereinafter also referred to as “component (C)”).

[0014] <Component (A)> Component (A) is at least one selected from the group consisting of amino alcohols and polyols.

[0015] The number average molecular weight of component (A) is not particularly limited as long as it is greater than 5,000, but from the viewpoint of the fluidity of the heat dissipation paste, it is preferably 5,100 to 30,000, more preferably 5,300 to 20,000, and particularly preferably 5,500 to 12,000. When the number average molecular weight of component (A) is within the above range, the resin composition tends to have good handleability after curing. By making the number average molecular weight of component (A) greater than 5,000, it is expected that the cured resin composition will be less likely to break, improving handleability.

[0016] <<Amino Alcohol>> The amino alcohol is not particularly limited as long as it has one or more hydroxyl groups and one or more amino groups, and examples thereof include hexamethylenediamine-isoprene copolymer diol obtained by copolymerizing hexamethylenediamine and isoprene and modifying the terminal alkyl groups with hydroxyl groups. These may be used alone or in combination of two or more.

[0017] The number of hydroxyl groups that the amino alcohol has is preferably 1 or 2, from the viewpoint of curability. The number of amino groups that the amino alcohol has is preferably 1 or 2, from the viewpoint of curability. The amino group that the amino alcohol has may be any of a primary amino group, a secondary amino group, and a tertiary amino group, but a tertiary amino group is preferred, from the viewpoint of curability. Examples of amino alcohols include (R １ ) ２ -N-R ２ In this case, compounds represented by R １ represents an alkyl group, and R ２ represents a hydroxyalkyl group. １ may be the same or different. １ R may be linear or branched. １ The number of carbon atoms in R is preferably 1 to 4 from the viewpoint of water solubility. ２ R may be linear or branched. ２The number of carbon atoms is preferably 1 to 4 from the viewpoint of water solubility.

[0018] <<Polyol>> The polyol is not particularly limited as long as it has two or more hydroxyl groups, and examples thereof include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, vegetable oil-based polyols, and other polyols. These may be used alone or in combination of two or more. Among these, from the viewpoint of the handleability of the cured product, polyether polyols, polyester polyols, polycarbonate polyols, and polyolefin polyols are preferred, polyether polyols and polyolefin polyols are more preferred, and polyolefin polyols are particularly preferred.

[0019] -Polyether polyol- The polyether polyol is not particularly limited, and examples thereof include polyols obtained by adding an alkylene oxide such as methylene oxide, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, or polyoxytetramethylene oxide to a compound having two or more active hydrogen groups. These may be used alone or in combination of two or more.

[0020] The compound having two or more active hydrogen groups is not particularly limited, and examples thereof include low molecular weight polyols, bisphenols, etc. These may be used alone or in combination of two or more.

[0021] The low molecular weight polyol is not particularly limited, and examples thereof include bifunctional low molecular weight polyols, trifunctional or higher functional low molecular weight polyols, etc. These may be used alone or in combination of two or more.

[0022] The bifunctional low molecular weight polyol is not particularly limited, and examples thereof include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, hexanediol, octanediol, nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,8-octane. Examples of suitable hydroxyl groups include diols, polyoxyethylene glycol (number of moles added: 10 or less), polyoxypropylene glycol (number of moles added: 10 or less), cyclohexanediol, cyclohexanedimethanol, tricyclodecane dimethanol, cyclopentadiene dimethanol, dimer diol, bisphenol A, N,N-bis(2-hydroxypropyl)aniline, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dihydroxypropionic acid, and dihydroxybenzoic acid. These may be used alone or in combination of two or more.

[0023] The tri- or higher functional low molecular weight polyol is not particularly limited, and examples thereof include trimethylolethane, trimethylolpropane, 1,1,1-trimethylolbutane, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,6-butanetriol, trimethylolbutene, trimethylolpentene, trimethylolhexene, trimethylolheptene, trimethyloloctene, trimethylolnonene, trimethyloldecene, trimethylolundecene, trimethyloldodecene, and trimethyloltridecene. , trimethylol pentadecene, trimethylol hexadecene, trimetrol heptadecene, trimethylol octadecene, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, trimethylol hexene, 1,2,3-octanetriol, 1,3,7-octanetriol, 3,7-dimethyl-1,2,3-octanetriol, 1,1,1-, 1, 1,1-trimethyloldecane, 1,2,10-decanetriol, 1,1,1-trimethylolisoheptadecane, 1,1,1-trimethylol-sec-butane, 1,1,1-trimethylol-tert-pentane, 1,1,1-trimethylol-tert-nonane, 1,1,1-trimethylol-tert-tridecane, 1,1,1-trimethylol-tert-heptadecane, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3-methyl-hexane, 1,1,1-trimethylol 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, 1,1,1-trimethylolisoheptadecane, 1,2,3,4-butanetetraol, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, diglycerin, triglycerin, polyglycerin, ditrimethylolethane, ditrimethylolpropane, tris(2-hydroxyethyl)isocyanurate, benzene-1,3,5-triol, benzene-1,2,3-triol, stilbene-3,Examples of such sugars include 4',5-triol, sucrose, inositol, sorbitan, sorbitol, mannitol, saccharose, cellulose, and xylitol. These sugars may be used alone or in combination of two or more.

[0024] The bisphenols are not particularly limited, and examples thereof include bisphenol A, bisphenol AP, bisphenol B, bisphenol C, bisphenol E, and bisphenol F. These may be used alone or in combination of two or more.

[0025] -Polyester Polyol- The polyester polyol is not particularly limited, and examples thereof include polyester polyols obtained by a condensation reaction between the above-mentioned low-molecular-weight polyol and a dibasic acid component. The dibasic acid component is not particularly limited, and examples thereof include aliphatic or aromatic dibasic acids such as terephthalic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic anhydride, isophthalic acid, trimellitic acid, glutaric acid, pimelic acid, suberic acid, and sebacic acid, as well as anhydrides thereof. These may be used alone or in combination of two or more.

[0026] Furthermore, polyester polyols that can be used include those obtained by ring-opening polymerization of cyclic ester compounds of lactones such as ε-caprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0027] -Polycarbonate polyol- There are no particular limitations on the polycarbonate polyol, and examples thereof include those obtained by reacting the above-mentioned low-molecular-weight polyol with a carbonate compound such as a dialkyl carbonate, an alkylene carbonate, a diaryl carbonate, etc. Dimethyl carbonate or diethyl carbonate can be used as the dialkyl carbonate, ethylene carbonate can be used as the alkylene carbonate, and diphenyl carbonate can be used as the diaryl carbonate.

[0028] -Polyolefin polyol- The polyolefin polyol is not particularly limited, and examples thereof include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene such as isoprene-modified diol in which the alkyl groups at the terminals of polyisoprene are modified with hydroxyl groups, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, hydroxyl group-containing chlorinated polyethylene, etc. These may be used alone or in combination of two or more.

[0029] -Vegetable Oil-Based Polyol- The vegetable oil-based polyol is not particularly limited, and examples thereof include polyols derived from plants such as castor oil, dimer acid, or soybean oil. These may be used alone or in combination of two or more.

[0030] The content of component (A) is preferably 5 to 40 mass %, more preferably 10 to 30 mass %, and particularly preferably 10 to 20 mass %, based on the total mass of the urethane (meth)acrylate. When the content of component (A) is within this range, a urethane (meth)acrylate with good fluidity in the thermal paste can be obtained.

[0031] <Component (B)> Component (B) is not particularly limited as long as it is a polyisocyanate having two or more isocyanate groups, and examples thereof include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. These may be used alone or in combination of two or more.

[0032] <<Aromatic Diisocyanate>> The aromatic diisocyanate is not particularly limited, and examples thereof include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, m-tetramethylxylene diisocyanate, p-tetramethylxylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, and 1,5-tetrahydronaphthalene diisocyanate. These may be used alone or in combination of two or more.

[0033] <<Aliphatic Diisocyanate>> The aliphatic diisocyanate is not particularly limited, and examples thereof include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, lysine ester triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate tetramethylene diisocyanate, pentamethylene diisocyanate, trimethylhexamethylene diisocyanate, etc. These may be used alone or in combination of two or more.

[0034] <<Alicyclic Diisocyanate>> The alicyclic diisocyanate is not particularly limited, and examples thereof include isophorone diisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, hydrogenated xylylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate, etc. These may be used alone or in combination of two or more.

[0035] The content of component (B) is preferably 20 to 90 mass %, more preferably 35 to 80 mass %, and particularly preferably 50 to 70 mass %, based on the total mass of the urethane (meth)acrylate. When the content of component (B) is within the above range, a urethane (meth)acrylate with good fluidity in the thermal paste can be obtained.

[0036] <Component (C)> Component (C) is not particularly limited as long as it is a (meth)acrylate having one or more hydroxyl groups. For example, it can be formed by polymerizing an ethylenically unsaturated monomer including a (meth)acrylic monomer, and may have a structural unit derived from the (meth)acrylic monomer. In this specification, the term "ethylenically unsaturated monomer" refers to a monomer having one or more polymerizable ethylenically unsaturated groups in the molecule. The presence of a hydroxyl group in component (C) promotes aggregation due to crosslinking, and the resulting resin composition tends to have good handleability after curing.

[0037] Specific examples of component (C) are not particularly limited and include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxy-3-allyloxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone adducts of these monomers (number of moles added: 1 to 5), polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, glycerin mono(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0038] Component (C) may or may not further have a crosslinking group other than a hydroxyl group. The crosslinking group other than a hydroxyl group is preferably at least one selected from the group consisting of a carboxy group, an epoxy group, an isocyanate group, an amino group, a hydrolyzable silyl group, and a nitrile group, and more preferably at least one selected from the group consisting of a carboxy group, an epoxy group, and an isocyanate group.

[0039] The glass transition point (Tg) of component (C) is not particularly limited, but is preferably −100° C. or higher, and more preferably −80° C. or higher. When Tg is −100° C. or higher, the thermal paste has good fluidity. The glass transition point can be determined using a DSC (differential scanning calorimeter).

[0040] The content of component (C) is not particularly limited, but is preferably 5 to 75 mass %, more preferably 15 to 50 mass %, and particularly preferably 20 to 40 mass %, based on the total mass of the urethane (meth)acrylate. When the content of component (C) is within the above range, a urethane (meth)acrylate with good fluidity in the thermal paste can be obtained.

[0041] <Solvent> The reaction (urethanization reaction) between component (A), component (B), and component (C) may be carried out using or without a solvent. When a solvent is used, the solvent may be removed under reduced pressure or normal pressure during the reaction or after completion of the reaction. There are no particular restrictions on the solvent that can be used in the reaction between component (A), component (B), and component (C), as long as it does not react with an isocyanate group, and any solvent can be used. Examples of such solvents include acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, toluene, xylene, anisole, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, m-cresol, γ-butyrolactone, γ-valerolactone, etc. These may be used alone or in combination of two or more.

[0042] <Catalyst> In the reaction (urethanization reaction) between component (A), component (B), and component (C), a catalyst may be used to adjust the reactivity. Known metal catalysts, amine catalysts, and the like can be used as the catalyst. There are no particular limitations on the metal catalyst, and examples thereof include dibutyltin dilaurate, dibutyltin acetate, dioctyltin dilaurate, tin octoate, dibutyltin di(2-ethylhexoate), lead 2-ethylhexoate, 2-ethylhexyl titanate, titanium ethyl acetate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, zinc naphthenate, cobalt naphthenate, and tetra-n-butyltin. These may be used alone or in combination of two or more. There are no particular limitations on the amine catalyst, and examples thereof include triethylenediamine, triethylamine, and tetramethylbutanediamine. These may be used alone or in combination of two or more. The amount of catalyst used is not particularly limited, but is preferably 0.01 to 1% by mass based on component (A).

[0043] <Thermal Polymerization Inhibitor> The reaction (urethanization reaction) between component (A), component (B), and component (C) is preferably carried out in the presence of a thermal polymerization inhibitor, from the viewpoint of suppressing reaction of the (meth)acryloyl groups. The thermal polymerization inhibitor is not particularly limited, and examples thereof include 2,6-di-tert-butyl-p-cresol, 4-methoxyphenol, and the like. These may be used alone or in combination of two or more.

[0044] The amount of the thermal polymerization inhibitor used is not particularly limited, but is preferably 0.01 to 1.5% by mass, more preferably 0.03 to 1.0% by mass, and particularly preferably 0.03 to 0.8% by mass, relative to 100% by mass of the reaction product.

[0045] <Polymerization initiator> A polymerization initiator may be used in the reaction (urethanization reaction) between component (A), component (B), and component (C). The polymerization initiator is not particularly limited, and known azo compounds and organic peroxides may be used. These may be used alone or in combination of two or more. The azo compound is not particularly limited, and examples thereof include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 1,1'-azobis(1-cyclohexanecarboxylate), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]. These may be used alone or in combination of two or more. The organic peroxide is not particularly limited, and examples thereof include benzoyl peroxide, t-butylperoxy 2-ethylhexaate, t-butylperbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionyl peroxide, and diacetyl peroxide. These may be used alone or in combination of two or more.

[0046] The amount of the polymerization initiator is not particularly limited, but from the viewpoint of curability, it is preferably 0.001 to 15 mass% based on the total amount of the monomers constituting component (C). When the amount of the polymerization initiator is within the above range, chain transfer polymerization proceeds effectively, which is preferable.

[0047] <Method for Producing Urethane (Meth)acrylate> Urethane (meth)acrylate can be produced by reacting (urethanization reaction) component (A), component (B), and component (C). When these components are reacted, the hydroxyl groups of component (A) and component (C) and the isocyanate group of component (B) form urethane bonds to produce the urethane (meth)acrylate.

[0048] The reaction temperature for the urethanization reaction is not particularly limited, but is preferably 50 to 150° C., more preferably 60 to 100° C. The reaction time for the urethanization reaction is not particularly limited, but is preferably 6 to 48 hours, more preferably 12 to 36 hours.

[0049] The proportions of the components in the urethanization reaction can be appropriately selected taking into consideration the number of hydroxyl groups in components (A) and (C), the physical properties after synthesis, etc. The ratio (NCO / OH) of the number of isocyanate groups in component (B) to the total number of hydroxyl groups in component (A) and component (C) is not particularly limited, but is preferably 0.5 to 2.

[0050] The proportion of component (A) relative to the total mass of component (A), component (B), and component (C) is not particularly limited, but from the viewpoint of good fluidity of the heat dissipation paste, it is preferably 1.0 to 30.0 mass%, more preferably 2.0 to 20.0 mass%, and particularly preferably 3.0 to 15.0 mass%.

[0051] The proportion of component (B) relative to the total mass of components (A), (B), and (C) is not particularly limited, but from the viewpoint of good fluidity of the heat dissipation paste, it is preferably 20.0 to 90.0 mass%, more preferably 30.0 to 80.0 mass%, and particularly preferably 40.0 to 70.0 mass%.

[0052] The proportion of component (C) relative to the total mass of component (A), component (B), and component (C) is not particularly limited, but from the viewpoint of good fluidity of the heat dissipation paste, it is preferably 3.0 to 50.0 mass%, more preferably 5.0 to 40.0 mass%, and particularly preferably 10.0 to 30.0 mass%.

[0053] In the urethane-forming reaction, it is preferable that substantially all of the isocyanate groups in component (B) react with component (A) or component (C). The infrared absorption spectrum of the reaction product is measured, and the isocyanate groups at wavelengths of 2200 to 2300 cm originating from the isocyanate residues are detected. －１ When the absorption of 1000 ppm is no longer observed, it can be determined that substantially all of the isocyanate groups in component (B) have reacted with component (A) or component (C).

[0054] The number average molecular weight of the urethane (meth)acrylate is preferably more than 5,000 and not more than 300,000, more preferably 10,000 to 100,000, from the viewpoint of good fluidity of the heat dissipation paste.

[0055] The content of the urethane (meth)acrylate relative to the total solid content by mass of the resin composition is not particularly limited, but from the viewpoint of handleability after curing, it is preferably 7.0 to 33.0 mass%, more preferably 8.0 to 25.0 mass%, and particularly preferably 8.0 to 19.0 mass%.

[0056] (Thermal Conductive Filler) The resin composition contains a thermally conductive filler. By including the thermally conductive filler, a layer (e.g., an adhesive layer, an insulating layer) made of a cured product with excellent thermal conductivity can be obtained. Here, the thermally conductive filler refers to an inorganic filler having a thermal conductivity of 20 W / m·K or more.

[0057] The material for the thermally conductive filler is not particularly limited as long as it has a thermal conductivity of 20 W / m K or more, and examples thereof include metal oxides such as boron nitride and aluminum oxide (alumina), metals such as silicon carbide and aluminum, silicon nitride, and aluminum nitride. These may be used alone or in combination of two or more. Among these, from the viewpoint of heat dissipation, boron nitride, aluminum oxide, silicon carbide, and aluminum are preferred, and boron nitride and aluminum oxide are more preferred.

[0058] The shape of the thermally conductive filler is not limited and can be appropriately selected from desired shapes, but spherical, plate-like, etc. are preferred.

[0059] The average particle size of the thermally conductive filler is not particularly limited, but from the viewpoint of obtaining a layer with excellent thermal conductivity and adhesion strength to the metal layer at low temperatures, it is preferably 1 to 50 μm, more preferably 3 to 40 μm, and particularly preferably 5 to 30 μm. The average particle size of particles such as thermally conductive fillers can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis using a laser diffraction / scattering particle size distribution analyzer, and the median diameter is used as the average particle size. A preferred measurement sample is one in which the thermally conductive filler is dispersed in water using ultrasonic waves. Examples of laser diffraction / scattering particle size distribution analyzers that can be used include the "LA-500" manufactured by Horiba, Ltd. and the "SALD2200" manufactured by Shimadzu Corporation. Specifically, measurements can be performed according to the method described in the examples below.

[0060] The thermally conductive filler may be surface-treated with a surface treatment agent to improve moisture resistance and dispersibility. The surface treatment agent is not particularly limited, and examples thereof include aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilane compounds, organosilazane compounds, and titanate coupling agents. These may be used alone or in combination of two or more. Among these, it is preferable to use an aminosilane coupling agent as the surface treatment in order to obtain a layer that has excellent kneadability with urethane (meth)acrylate and excellent peel strength. The surface treatment agent may be used alone or in combination of two or more.

[0061] Commercially available surface treatment agents include, but are not limited to, Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM5783" (N-phenyl-3-aminooctyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy silane coupling agent). These may be used alone or in combination of two or more.

[0062] The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the thermally conductive filler. There are no particular restrictions on the amount of carbon per unit surface area of ​​the thermally conductive filler. From the viewpoint of improving the dispersibility of the thermally conductive filler and suppressing an increase in the melt viscosity of the resin varnish and the melt viscosity in the form of a sheet, the amount of carbon per unit surface area is preferably 0.02 to 1.0 mg / m ２ , more preferably 0.05 to 0.8 mg / m ２ , particularly preferably 0.1 to 0.5 mg / m ２ The carbon amount per unit surface area of ​​the thermally conductive filler can be measured after the surface-treated thermally conductive filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the thermally conductive filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solid content, the carbon amount per unit surface area of ​​the thermally conductive filler can be measured using a carbon analyzer. As the carbon analyzer, an "EMIA-320V" manufactured by Horiba, Ltd. or the like can be used.

[0063] The content of the thermally conductive filler relative to the total solid mass of the resin composition is not particularly limited, but from the viewpoint of handleability after curing, it is preferably 50.0 to 92.0 mass%, more preferably 60.0 to 95.0 mass%, and particularly preferably 65.0 to 90.0 mass%.

[0064] (Crosslinking Agent) Examples of the crosslinking agent include a thermosetting crosslinking agent and a photocurable crosslinking agent. These may be used alone or in combination of two or more. Among these, a thermosetting crosslinking agent is preferred from the viewpoint of curability.

[0065] Since component (C) in the urethane (meth)acrylate has a hydroxyl group as a crosslinking group in the molecule, the hydroxyl group reacts with the crosslinking agent to promote aggregation due to crosslinking, thereby increasing the degree of cure of the resulting resin composition.

[0066] The crosslinking agent is not particularly limited, but preferably has two or more functional groups in the molecule that can react with the hydroxyl groups contained in the urethane (meth)acrylate. The functional groups that can react with the hydroxyl groups are not particularly limited, and examples thereof include an isocyanate group, an epoxy group, a carboxy group, and an amino group.

[0067] <Crosslinking agent containing an isocyanate group> The crosslinking agent containing an isocyanate group is not particularly limited, and examples thereof include the polyisocyanates described in the section on component (B) above, their biurets, nurates, adducts, and other condensates. These may be used alone or in combination of two or more.

[0068] The biuret compound is not particularly limited, and examples thereof include biuret compounds of hexamethylene diisocyanate (product name "Sumidur N-75", manufactured by Sumika Bayer Urethane Co., Ltd.; product name "Duranate 24A-100", manufactured by Asahi Kasei Chemicals Corporation).

[0069] The nurate form is not particularly limited, and examples thereof include a nurate form of hexamethylene diisocyanate (product name "Sumidur N-3300", manufactured by Sumika Bayer Urethane Co., Ltd.), a nurate form of isophorone diisocyanate (product name "Desmodur Z-4370", manufactured by Sumika Bayer Urethane Co., Ltd.), a nurate form of tolylene diisocyanate (product name "Coronate 2030", manufactured by Nippon Polyurethane Co., Ltd.), and triallyl isocyanurate (product name "TAIC", manufactured by Mitsubishi Chemical Corporation). These may be used alone or in combination of two or more.

[0070] The adduct is not particularly limited, and examples thereof include a hexamethylene diisocyanate adduct of trimethylolpropane (product name "Takenate D-160N", manufactured by Mitsui Chemicals, Inc.) and an isophorone diisocyanate adduct of trimethylolpropane (product name "Takenate D-140N", manufactured by Mitsui Chemicals, Inc.). These may be used alone or in combination of two or more.

[0071] The other condensates are not particularly limited, and examples thereof include polymethylene polyphenyl polyisocyanate (product name "PAPI27", manufactured by Dow), a biuret of hexamethylene diisocyanate (product name "Takenate D-165N", manufactured by Mitsui Chemicals, Inc.), and carbodiimide-modified diphenylmethane diisocyanate (product name "Isonate 143L", manufactured by Dow). These may be used alone or in combination of two or more.

[0072] <Crosslinking Agent Containing Epoxy Group> The crosslinking agent containing an epoxy group is not particularly limited, and examples thereof include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidylaminophenylmethane, etc. These may be used alone or in combination of two or more.

[0073] <Crosslinking Agent Containing Carboxy Group> The crosslinking agent containing a carboxy group is not particularly limited, and examples thereof include succinic acid, adipic acid, sebacic acid, maleic acid, phthalic acid, naphthalenedicarboxylic acid, methylphthalic acid, cyclohexanedicarboxylic acid, methylcyclohexanedicarboxylic acid, methylnorbornenedicarboxylic acid, tetrahydrophthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetetracarboxylic acid, etc. These may be used alone or in combination of two or more.

[0074] <Crosslinking Agent Containing Amino Group> The crosslinking agent containing an amino group is not particularly limited, and examples thereof include diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, pentamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, and p-phenylenediamine; 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, and di-2-hydroxyethylethylenediamine; Examples of suitable amines include diamines having a hydroxyl group, such as ethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine; and polyfunctional amines having three or more functional groups, such as diethylenetriamine, iminobispropylamine, triethylenetetramine, N-(3-aminopropyl)butane-1,4-diamine, 6,6-iminodihexylamine, 3,7-diazanonane-1,9-diamine, N,N'-bis(3-aminopropyl)ethylenediamine, and JEFFAMINE D-230, D-400, D-2000, T-403, and T-3000 (all manufactured by HUNTSMAN). These may be used alone or in combination of two or more.

[0075] The content of the crosslinking agent relative to the total solid content by mass of the resin composition is not particularly limited, but from the viewpoint of heat resistance, it is preferably 1.0 to 17.0 mass%, more preferably 2.0 to 10.0 mass%, and particularly preferably 3.0 to 9.0 mass%.

[0076] The total content of the urethane (meth)acrylate, the thermally conductive filler, and the crosslinking agent relative to the total solid content by mass of the resin composition is not particularly limited, but is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0077] (Other Components) The resin composition of the present invention may or may not further contain other components such as a solvent and an additive, as long as the effects of the present invention are not impaired.

[0078] <Solvent> The solvent is not particularly limited, and examples thereof include methyl ethyl ketone, toluene, water, etc. These may be used alone or in combination of two or more. Among these, methyl ethyl ketone is preferred from the viewpoint of solvent solubility.

[0079] The content of the solvent relative to the total mass of the resin composition is not particularly limited, but from the viewpoint of dispersibility, it is preferably 0.1 to 50.0 mass%, more preferably 5.0 to 45.0 mass%, and particularly preferably 10.0 to 40.0 mass%.

[0080] <Additives> Various additives can be used without limitation depending on the application, as long as they do not deviate from the spirit of the present invention, and examples thereof include radical initiators, ultraviolet inhibitors, antistatic agents, tackifiers, silane coupling agents, antioxidants, polymerization inhibitors, pigments, colorants, plasticizers, softeners, processing aids, antifoaming agents, fillers, viscosity modifiers, dispersants, leveling modifiers, antireflection agents, fluorescent agents, light diffusing agents, light stabilizers, refractive index modifiers, matting agents, fillers, and surfactants.These may be used alone or in combination of two or more.Among these, radical initiators are preferred from the viewpoint of curability.

[0081] The content of the additives relative to the total mass of the resin composition is not particularly limited, but from the viewpoint of good fluidity of the heat dissipation paste, it is preferably 0.1 to 10.0 mass%, more preferably 0.2 to 5.0 mass%, and particularly preferably 0.3 to 2.0 mass%.

[0082] When the resin composition is in the form of a film, the thickness of the film-like resin composition (hereinafter referred to as "resin film") is not particularly limited and can be appropriately designed depending on the application, and can be, for example, about 1 to 300 μm. When the resin composition is in the form of a molded product, the shape of the molded product is not limited and can be appropriately selected from desired shapes.

[0083] The thermal conductivity of the cured product of the resin composition is not particularly limited, but from the viewpoint of heat dissipation when applied to a heat dissipation module, it is preferably 5 W / m K or more, more preferably 7.5 W / m K or more, and particularly preferably 10 W / m K or more.

[0084] [Heat Dissipating Device] The heat dissipating device of the present invention includes an adhesive layer formed from a cured product of the resin composition of the present invention. One embodiment of the heat dissipating device includes, for example, a heat generating element, an adhesive layer, and a heat sink in this order. Another embodiment of the heat dissipating device includes a heat sink, an adhesive layer, and another heat sink, with the heat generating element embedded in the adhesive layer. There are no particular limitations on the heat sink as long as it has heat dissipation properties.

[0085] The heat dissipation device is not particularly limited, and examples thereof include an LED, a power module, and an electrostatic chuck.

[0086] The adhesive layer is usually formed by laminating a resin sheet with a heating element and a heat sink. This lamination can be performed, for example, by removing the protective film from the resin sheet and then heat-pressing the resin sheet to the heating element from the support side, thereby laminating the resin composition layer to the heating element. The member for heat-pressing the resin sheet to the heating element (hereinafter sometimes referred to as the "heat-pressure bonding member") is not particularly limited, and examples include a heated metal plate (such as a SUS panel) or a metal roll (SUS roll). Note that rather than pressing the heat-pressure bonding member directly onto the resin sheet, it is preferable to press it via an elastic material such as heat-resistant rubber so that the resin sheet can sufficiently follow the surface irregularities of the heating element.

[0087] The heating element and the resin sheet may be laminated, for example, by a vacuum lamination method. The thermocompression temperature in the vacuum lamination method is not particularly limited, but is preferably 60 to 160°C, more preferably 80 to 140°C. The thermocompression pressure in the vacuum lamination method is not particularly limited, but is preferably 0.098 to 1.77 MPa, more preferably 0.29 to 1.47 MPa. The thermocompression time in the vacuum lamination method is not particularly limited, but is preferably 20 to 400 seconds, more preferably 30 to 300 seconds. The lamination is preferably carried out under reduced pressure conditions of 13 hPa or less.

[0088] After lamination, the laminated resin sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the support side. The pressing conditions for the smoothing treatment may be the same as the thermocompression conditions for lamination. Note that lamination and smoothing may be performed consecutively using a vacuum laminator.

[0089] After lamination, the support of the resin sheet is peeled off, and the heat sink is laminated so as to be joined to the resin composition layer of the laminate in which the heating element and the resin composition layer are laminated. The lamination method is as described above.

[0090] After forming a resin composition layer on a heat sink, the resin composition layer is thermally cured to form an adhesive layer. The thermal curing conditions for the resin composition layer vary depending on the type of resin composition, etc. The curing temperature for the resin composition layer is not particularly limited, but is preferably 120 to 240°C, more preferably 150 to 220°C, and particularly preferably 170 to 200°C. The curing time for the resin composition layer is not particularly limited, but is preferably 5 to 120 minutes, particularly preferably 10 to 100 minutes, and more preferably 15 to 90 minutes.

[0091] Before thermally curing the resin composition layer, the resin composition layer may be subjected to a preheating treatment in which the resin composition layer is heated at a temperature lower than the curing temperature. The resin composition layer may be preheated prior to thermally curing. The preheating temperature is not particularly limited, but is preferably 50°C or higher and lower than 120°C, more preferably 60 to 110°C, and particularly preferably 70 to 100°C. The preheating time is not particularly limited, but is preferably 5 minutes or longer, more preferably 5 to 150 minutes, and particularly preferably 15 to 120 minutes.

[0092] In this way, the heat dissipation device can be manufactured. In forming the adhesive layer, the method of laminating the resin sheet and the heat generating element has been described above, but the resin sheet and the heat sink may be laminated first.

[0093] [Electronic Device] The electronic device of the present invention includes an insulating layer formed from a cured product of the resin composition of the present invention. The electronic device of the present invention is not particularly limited, and examples thereof include a circuit board, a semiconductor chip package, and a semiconductor device.

[0094] (Circuit Board) The circuit board includes an insulating layer formed from a cured product of the resin composition of the present invention. This circuit board can be produced, for example, by a production method including the following steps (1) and (2): (1) a step of forming a resin composition layer on a substrate; and (2) a step of thermally curing the resin composition layer to form an insulating layer. For details of the production method of such a circuit board, please refer to the descriptions in paragraphs 0053 to 0062 of JP 2015-178620 A, the contents of which are incorporated herein by reference.

[0095] (Semiconductor Chip Package) A semiconductor chip package includes the above-described circuit board and a semiconductor chip mounted on the circuit board. This semiconductor chip package can be manufactured by bonding the semiconductor chip to the circuit board.

[0096] The bonding conditions for the circuit board and the semiconductor chip can be any conditions that allow conductive connection between the terminal electrodes of the semiconductor chip and the circuit wiring of the circuit board. For example, the conditions used in flip-chip mounting of semiconductor chips can be used. Furthermore, for example, the semiconductor chip and the circuit board can be bonded via an insulating adhesive.

[0097] An example of a bonding method is a method in which a semiconductor chip is pressure-bonded to a circuit board. The pressure-bonding temperature is not particularly limited, but is preferably 120°C to 240°C. The pressure-bonding time is not particularly limited, but is preferably 1 to 60 seconds. Alternatively, the semiconductor chip may be bonded to the circuit board by reflow.

[0098] After bonding the semiconductor chip to the circuit board, the semiconductor chip may be filled with a mold underfill material, which may be the resin composition described above or the resin sheet described above.

[0099] A semiconductor chip package according to another embodiment includes a semiconductor chip and a cured product of the resin composition that encapsulates the semiconductor chip. In such a semiconductor chip package, the cured product of the resin composition typically functions as an encapsulating layer. An example of a semiconductor chip package according to another embodiment is a fan-out type WLP.

[0100] A method for manufacturing a semiconductor chip package such as a fan-out type WLP includes: (A) a step of laminating a temporary fixing film on a substrate; (B) a step of temporarily fixing a semiconductor chip on the temporary fixing film; (C) a step of laminating a layer made of the resin composition of the present invention on the semiconductor chip, or a step of applying the resin composition of the present invention on the semiconductor chip and thermally curing the layer to form a sealing layer; (D) a step of peeling the substrate and the temporary fixing film from the semiconductor chip; (E) a step of forming a rewiring formation layer (insulating layer) on the surface of the semiconductor chip from which the substrate and the temporary fixing film have been peeled; (F) a step of forming a conductor layer (rewiring layer) on the rewiring formation layer (insulating layer); and (G) a step of forming a solder resist layer on the conductor layer. The method for manufacturing a semiconductor chip package may also include a step of (H) dicing a plurality of semiconductor chip packages into individual semiconductor chip packages.

[0101] For details of the manufacturing method of such a semiconductor chip package, please refer to paragraphs 0066 to 0081 of International Publication No. 2016 / 035577, the contents of which are incorporated herein by reference.

[0102] A semiconductor chip package according to still another embodiment is, for example, a semiconductor chip package in which a rewiring formation layer or a solder resist layer in the semiconductor chip package according to the other embodiment is formed from a cured product of the resin composition of the present invention.

[0103] (Semiconductor Device) Examples of semiconductor devices on which the above-mentioned semiconductor chip package is mounted include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, smartphones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

[0104] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the examples described below, and various modifications are possible as long as they do not change the gist of the present invention. Among Examples 1 to 7, Examples 1 to 5 are working examples, and Examples 6 and 7 are comparative examples.

[0105] [Measurement Methods] The methods for measuring the various physical properties are as follows.

[0106] (Number average molecular weight (Mn)) Mn was measured in terms of polystyrene by gel permeation chromatography (GPC) under the following conditions, and calculated from these values. [Measurement conditions] - Instrument used: "HLC-8320GPC", manufactured by Tosoh Corporation - Column used: "TSKgel (registered trademark) SuperMultiporeHZ-M", manufactured by Tosoh Corporation - Detector: Refractive index (RI) detector - Detection temperature: 40°C - Eluent: Tetrahydrofuran - Flow rate: 0.350 mL / min - Sample concentration: 0.5% by mass - Sample injection amount: 10 μL - Standard sample: Polystyrene

[0107] [Production Example 1 (Urethane (meth)acrylate UA1)] As shown in Table 1, 200 parts by mass of 2-hydroxyethyl acrylate, 100 parts by mass of an isoprene-modified diol having an Mn of 7,500 in which the alkyl groups at the terminals of polyisoprene were modified with hydroxyl groups, 0.2 parts by mass of dibutyltin dilaurate, 0.8 parts by mass of 2,6-di-tert-butyl-p-cresol, and 500 parts by mass of hexamethylene diisocyanate were added to a four-neck flask equipped with a thermometer, a condenser, and a stirrer, and after thorough stirring, the mixture was heated to 70°C and reacted with stirring for approximately 24 hours. After the reaction, it was confirmed by infrared absorption spectroscopy that no isocyanate residues were detected, yielding a mixture UA1 containing urethane (meth)acrylate.

[0108] [Production Example 2 (Urethane (meth)acrylate UA2)] As shown in Table 1, a mixture UA2 containing urethane (meth)acrylate was obtained in the same manner as in Production Example 1, except that, instead of the isoprene-modified diol having an Mn of 7,500 used in Production Example 1, a butanol-terminated propylene oxide (PO)-modified polyol having an Mn of 10,000 was used, which was obtained by ring-opening polymerization of propylene oxide using butanol as an initiator.

[0109] [Production Example 3 (Urethane (meth)acrylate UA3)] As shown in Table 1, a mixture UA3 containing urethane (meth)acrylate was obtained in the same manner as in Production Example 1, except that a hexamethylenediamine-isoprene copolymer diol having an Mn of 6,000, which was obtained by copolymerizing hexamethylenediamine and isoprene and modifying the terminal alkyl groups with hydroxyl groups, was used instead of the isoprene-modified diol having an Mn of 7,500 used in Production Example 1.

[0110] [Production Example 4 (Urethane (meth)acrylate UA4)] As shown in Table 1, a mixture UA4 containing urethane (meth)acrylate was obtained in the same manner as in Production Example 1, except that an isoprene-modified diol having Mn of 800, in which the alkyl groups at the terminals of polyisoprene were modified with hydroxyl groups, was used instead of the isoprene-modified diol having Mn of 7,500 used in Production Example 1.

[0111] [Production Example 5 (Urethane (meth)acrylate UA5)] As shown in Table 1, a mixture UA5 containing urethane (meth)acrylate was obtained in the same manner as in Production Example 1, except that an isoprene-modified diol having an Mn of 2,500, in which the alkyl groups at the terminals of polyisoprene were modified with hydroxyl groups, was used instead of the isoprene-modified diol having an Mn of 7,500 used in Production Example 1.

[0112]

[0113] [Thermal conductive filler] D1: spherical alumina, average particle size 25 μm, specific surface area 0.2 m ２ / g (trade name "DAM-20", manufactured by Denka Co., Ltd.) D2: plate-shaped boron nitride, average particle size 8 μm, specific surface area 6 m ２ / g (trade name "GP", manufactured by Denka Co., Ltd.) The average particle size of the thermally conductive filler was measured using a laser diffraction particle size distribution analyzer. The specific surface area of ​​the thermally conductive filler was measured using a specific surface area analyzer.

[0114] [Crosslinking agent] TAIC (triallyl isocyanurate) [Radical initiator] Parkmil D (NOF Corporation) [Solvent] MEK (methyl ethyl ketone)

[0115] [Preparation of Resin Varnish] <Examples 1 to 7> 6.3 parts by mass of urethane (meth)acrylate (UA1), 3.2 parts by mass of TAIC as a crosslinking agent, 0.6 parts by mass of Percumyl D as a radical initiator, 42.9 parts by mass of spherical alumina D1 as a thermally conductive filler, 17.1 parts by mass of plate-shaped boron nitride D2 as a thermally conductive filler, and 30.0 parts by mass of methyl ethyl ketone were mixed and uniformly dispersed in a high-speed rotating mixer to prepare a resin varnish with a solids content of 70% by mass. For Examples 2 to 7, resin varnishes were also prepared using the formulations shown in Table 2.

[0116] [Evaluation Method] <Thermal Conductivity> Two sheets of PET film were prepared by coating the resin varnish obtained in each example, and the PET films with the coating layers were sandwiched between each other and then cured in a press at 180°C for 15 minutes to obtain a 0.2 mm thick sheet of cured product. The thermal conductivity of the obtained cured product was measured according to the following method. Using two of the 0.2 mm thick sheets obtained above, the thermal conductivity was measured with a thermal conductivity meter (TPA-501, manufactured by Kyoto Electronics Manufacturing Co., Ltd.). The results are shown in Table 2. The evaluation criteria are as follows. <<Evaluation Criteria>> ○: Thermal conductivity is 5 W / m·K or more ×: Thermal conductivity is less than 5 W / m·K

[0117] <Handling Ease> The 0.2 mm thick sheet obtained in the above thermal conductivity measurement was cut into 2 cm square pieces and peeled off, and the handling ability was evaluated according to the following evaluation criteria. The results are shown in Table 2. <<Evaluation Criteria>> ○ (Good): The sheet was able to be cut and peeled off from the PET film without tearing. × (Poor): Due to weak strength, it was torn or had excessive deformation.

[0118] <Filling Ability of Varnish> The filling ability of the obtained resin varnish was evaluated. The viscosity of the resin varnish was measured at 25°C using a rheometer (manufactured by Nippon Signal Hegner, product name: MCR300, circular flat plate (diameter: 25 mmφ), gap: 1 m). The filling ability was evaluated based on the obtained results and the following evaluation criteria. The results are shown in Table 2. Note that if the viscosity of the resin varnish is extremely low, the resin may flow out when filling gap holes, etc., with the resin varnish. If the viscosity of the resin varnish is extremely high, the resin may not flow easily when filling. Therefore, the appropriate viscosity range was set to 10,000 mPa·s or more and less than 1,000,000 mPa·s. <<Evaluation Criteria>> ○: Viscosity at a shear rate of 60 rpm is 10,000 mPa·s or more and less than 1,000,000 mPa·s. ×: Viscosity at a shear rate of 60 rpm is less than 10,000 mPa·s.

[0119]

[0120] From Table 2, it can be seen that Examples 1 to 5, which respectively used mixtures UA1 to UA3 containing a urethane (meth)acrylate that is a reaction product of a predetermined hydroxyl group-containing polymer component (A) having a number average molecular weight of more than 5000, a polyisocyanate component (B) having two or more isocyanate groups, and a (meth)acrylate component (C) having one or more hydroxyl groups, have good handleability after curing while maintaining the basic properties of heat dissipation and fluidity of the heat dissipation paste, compared to Examples 6 to 7, which respectively used mixtures UA4 to UA5 containing a urethane (meth)acrylate that is a reaction product of a hydroxyl group-containing polymer component (A) having a number average molecular weight of 5000 or less, a polyisocyanate component (B) having two or more isocyanate groups, and a component (C) having one or more hydroxyl groups.

Claims

1. A resin composition comprising a urethane (meth)acrylate, a thermally conductive filler, and a crosslinking agent, wherein the urethane (meth)acrylate is at least one selected from the group consisting of aminoalcohols having one or more hydroxyl groups and one or more amino groups, and polyols having two or more hydroxyl groups, and is a reaction product of a hydroxyl group-containing polymer having a number average molecular weight of more than 5,000, a polyisocyanate having two or more isocyanate groups, and a (meth)acrylate having one or more hydroxyl groups.

2. The resin composition according to claim 1, wherein the thermally conductive filler is at least one selected from the group consisting of boron nitride, aluminum oxide, silicon carbide, and aluminum.

3. The resin composition according to claim 1 or 2, wherein the content of the urethane (meth)acrylate is 7.0 to 33.0 mass % based on the total solid mass of the resin composition.

4. The resin composition according to claim 1 or 2, wherein the content of the thermally conductive filler is 50.0 to 92.0 mass % based on the total solid mass of the resin composition.

5. The resin composition according to claim 1 or 2, wherein the content of the crosslinking agent is 1.0 to 17.0 mass % based on the total solid mass of the resin composition.

6. The resin composition according to claim 1 or 2, wherein the cured product of the resin composition has a thermal conductivity of 5 W / m·K or more.

7. A heat dissipation device comprising an adhesive layer formed from the cured product of the resin composition according to claim 1 or 2.

8. An electronic device comprising an insulating layer formed from a cured product of the resin composition according to claim 1 or 2.

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