Composition containing (meth) acrylic polymer and metal particles

Abstract

The present invention provides a composition containing: a (meth) acrylic polymer having (meth) acryloyl groups at both ends of a poly (meth) acrylate chain; and metal particles.

Description

Technical Field

[0001] The present invention relates to a composition containing a (meth)acrylic polymer and metal particles. Background Art

[0002] Electronic parts such as processors, power modules, and batteries for electric vehicles generate heat during use. In order to protect such parts from heat, a mechanism that efficiently dissipates the generated heat is required. A thermally conductive material (sometimes also called a heat sink) called a thermal interface material (TIM) is a material that is disposed between a heat source and a heat sink or other heat dissipation component to reduce the thermal resistance between the heat source and the heat dissipation component and promote heat conduction from the heat source. The heat generated from the heat source is efficiently conducted to the cooling component via the TIM, so it is easy to dissipate heat from the heat dissipation component.

[0003] As thermally conductive materials, many liquid materials also called heat dissipation grease or thermally conductive grease are known. However, when using liquid thermally conductive grease, there may be a phenomenon in which the grease is squeezed out from between parts due to dripping after application or deformation of the parts applied with the thermally conductive grease. In order to solve such a problem, a thermally conductive material formed into a solid state such as a sheet is sometimes used. As a solid thermally conductive material, for example, a thermally conductive sheet containing thermally conductive particles and a cured product of a polymerizable compound has been studied.

[0004] Patent Document 1 describes an acrylic thermally conductive composition containing a monofunctional (meth)acrylate, a polyfunctional (meth)acrylate, a photopolymerization initiator, thermally conductive particles, a plasticizer, and a thiol compound, and a thermally conductive sheet having a thermally conductive resin layer obtained by photocuring the composition.

[0005] Previous technical literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2015-221863 Summary of the invention

[0008] Technical issues to be solved by the invention

[0009] The thermally conductive material preferably has high heat resistance to cope with various heat sources. However, according to the study of the present inventors, it is difficult to achieve high heat resistance when metal particles are used as thermally conductive particles.

[0010] An object of the present invention is to provide a composition capable of forming a cured product having excellent heat resistance.

[0011] Means for solving technical problems

[0012] The present inventors have found that, when metal particles are used, a composition capable of forming a cured product having excellent heat resistance can be obtained by simultaneously using a (meth)acrylic polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain.

[0013] The present invention provides the following [1] to [9] in several aspects.

[0014] [1] A composition comprising: a (meth)acrylic acid-based polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain; and metal particles.

[0015] [2] The composition according to [1], wherein

[0016] The glass transition temperature of the (meth)acrylic polymer is -40°C or lower.

[0017] [3] The composition according to [1] or [2], wherein

[0018] The weight average molecular weight of the (meth)acrylic acid-based polymer is 19,000 or more.

[0019] [4] The composition according to any one of [1] to [3], wherein

[0020] The viscosity of the (meth)acrylic acid-based polymer at 23° C. is 200 Pa·s or more.

[0021] [5] The composition as described in any one of [1] to [4], which further contains a compound having a (meth)acryloyl group, wherein the compound having a (meth)acryloyl group includes a compound having a (meth)acryloyl group and a carboxyl group, and the content of the compound having a (meth)acryloyl group and a carboxyl group is 8% by mass or less based on the total mass of the compound having a (meth)acryloyl group.

[0022] [6] The composition according to any one of [1] to [5], wherein

[0023] The metal particles are silver particles.

[0024] [7] The composition according to any one of [1] to [6], which is used for forming a heat dissipation material.

[0025] [8] A cured product, which is a cured product of the composition according to any one of [1] to [7].

[0026] [9] An article comprising: a heat source; and the cured product according to [8] in thermal contact with the heat source.

[0027] Effects of the Invention

[0028] According to one aspect of the present invention, a composition capable of forming a cured product having excellent heat resistance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic cross-sectional view showing one embodiment of the article.

[0030] Figure 2 It is a schematic cross-sectional view showing another embodiment of the article. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0032] The term "(meth)acryloyl" in the present specification refers to "acryloyl" and its corresponding "methacryloyl", and the same also applies to similar expressions such as "(meth)acrylate" and "(meth)acrylic acid".

[0033] The weight average molecular weight (Mw), number average molecular weight (Mn), and the ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) in this specification refer to values ​​determined by measuring using gel permeation chromatography (GPC) under the following conditions and using polystyrene as a standard substance.

[0034] · Measurement equipment: HLC-8320GPC (product name, manufactured by TOSOH CORPORATION)

[0035] Analytical column: TSKgel SuperMultipore HZ-H (3 connected) (product name, manufactured by TOSOH CORPORATION)

[0036] Guard column: TSKguardcolumn SuperMP(HZ)-H (product name, manufactured by TOSOH CORPORATION)

[0037] ·Eluent: THF

[0038] ·Measurement temperature: 25℃

[0039] A composition according to one embodiment of the present invention contains a (meth)acrylic acid polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain (hereinafter, also referred to as "(meth)acrylic acid polymer") and metal particles. Since the composition contains the (meth)acrylic acid polymer, the cured product of the composition has excellent heat resistance. In addition, in one embodiment, since the composition contains the (meth)acrylic acid polymer, the cured product of the composition may have low elasticity.

[0040] From the viewpoint of lower elasticity and excellent elongation of the cured product, the glass transition temperature (Tg) of the (meth)acrylic polymer may be 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, further preferably -30°C or lower, and particularly preferably -40°C or lower. The Tg of the (meth)acrylic polymer may be -70°C or higher, -60°C or higher, or -55°C or higher. The glass transition temperature refers to a value measured by differential scanning calorimetry.

[0041] The (meth)acrylic polymer may be in liquid form at 23° C. In this case, from the viewpoint of easy application to the coating surface and the viewpoint of improving the adhesion of the cured product to the coating surface, the viscosity of the (meth)acrylic polymer at 23° C. may be 1000 Pa·s or less, 900 Pa·s or less, or 800 Pa·s or less. From the viewpoint of better elongation of the cured product, the viscosity of the (meth)acrylic polymer at 23° C. may be 1 Pa·s or more, 50 Pa·s or more, 100 Pa·s or more, 200 Pa·s or more, 300 Pa·s or more, 400 Pa·s or more, or 500 Pa·s or more.

[0042] In this specification, viscosity refers to a value measured in accordance with JIS Z8803, specifically, a value measured by an E-type viscometer (for example, PE-80L manufactured by TOKI SANGYO CO., LTD.) The viscometer can be calibrated in accordance with JIS Z8809-JS14000.

[0043] From the viewpoint of lower elasticity and excellent elongation of the cured product, the weight average molecular weight of the (meth)acrylic polymer is preferably 3000 or more, 4000 or more, 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, 10000 or more, 11000 or more, 12000 or more, 13000 or more, 15000 or more, 19000 or more, 21000 or more, 23000 or more, or 25000 or more. From the viewpoint of easy adjustment of the viscosity of the composition, the weight average molecular weight of the (meth)acrylic polymer is preferably 150000 or less, 120000 or less, 100000 or less, 80000 or less, 60000 or less, or 40000 or less.

[0044] The two (meth)acryloyl groups present at the two ends of the (meth)acrylic polymer may be acryloyl or methacryloyl groups, respectively and independently. The poly(meth)acrylate chain includes (meth)acrylate as a monomer unit. The (meth)acrylate as a monomer unit may have hydrocarbon groups such as alkyl, aryl (phenyl, toluoyl, etc.), benzyl, etc.; organic groups having oxygen atoms such as alkoxy, hydroxyl, carboxyl, glycidyl, etc.; groups having nitrogen atoms such as amino, nitrile, etc., etc.

[0045] The hydrocarbon group may be chain-shaped or may have a ring (e.g., an aromatic ring). The number of carbon atoms of the hydrocarbon group may be, for example, 1 or more or 18 or less. The (meth)acrylate having a hydrocarbon group may be an alkyl (meth)acrylate, an aryl (meth)acrylate, a benzyl (meth)acrylate, or the like. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate.

[0046] Examples of the (meth)acrylate having an organic group having an oxygen atom include 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, carboxyl (meth)acrylate, and glycidyl (meth)acrylate.

[0047] Examples of the (meth)acrylate having an organic group having a nitrogen atom include 2-aminoethyl (meth)acrylate and nitrile (meth)acrylate.

[0048] From the viewpoint of achieving better heat resistance of the cured product, the content of the (meth)acrylic polymer may be 0.5% by mass or more, 1% by mass or more, or 3% by mass or less, or 10% by mass or less, 8% by mass or less, or 6% by mass or less, based on the total mass of the composition.

[0049] For the purpose of adjusting the physical properties of the cured product, the composition may contain, in addition to the (meth)acrylic acid polymer, other polymerizable compounds other than the (meth)acrylic acid polymer (details will be described later). From the viewpoint of better heat resistance of the cured product, the content of the (meth)acrylic acid polymer is preferably 5 parts by mass or more, 10 parts by mass or more, 20 parts by mass or more, 30 parts by mass or more, or 35 parts by mass or more, and may be, for example, 80 parts by mass or less, 70 parts by mass or less, 60 parts by mass or less, 50 parts by mass or less, or 45 parts by mass or less, relative to 100 parts by mass of the total of the (meth)acrylic acid polymer and other polymerizable compounds (hereinafter referred to as "the total content of the polymerizable components").

[0050] The metal forming the metal particles may be, for example, silver, gold, copper, aluminum, etc. From the viewpoint of excellent thermal conductivity of the cured product, the metal particles are preferably silver particles. Based on the total mass of the metal particles, the content of the metal in the metal particles is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and particularly preferably 99% by mass or more. The metal particles may be particles substantially formed only of metal (particles substantially 100% by mass of the particles are metal particles, or particles formed only of metal and inevitable impurities).

[0051] From the viewpoint of achieving better thermal conductivity of the cured product, the thermal conductivity of the metal particles may be 200 W / (m·K) or more, 250 W / (m·K) or more, 300 W / (m·K) or more, 350 W / (m·K) or more, or 400 W / (m·K) or more.

[0052] The shape of the metal particles can be flaky, spherical, massive, dendritic, plate-like, etc. From the viewpoint of the better thermal conductivity of the cured product, the shape of the metal particles is preferably flaky. As the metal particles, two or more metal particles with different shapes can be used.

[0053] From the viewpoint of better thermal conductivity of the cured product, the average particle size of the metal particles is preferably 1.0 μm or more, 3.0 μm or more, or 5.0 μm or more, and 16.0 μm or less, 14.0 μm or less, 12.0 μm or less, or 10.0 μm or less. The average particle size of the metal particles can be measured by a laser diffraction particle size distribution measuring device (laser diffraction method).

[0054] The BET specific surface area of ​​metal particles can be 0.08 m 2 / g or above or 0.1m 2 / g or more, can be 1m 2 / g or less, 0.8m 2 / g or less or 0.5m 2 / g or less.

[0055] From the viewpoint of better thermal conductivity of the cured product, the content of the metal particles is preferably 60% by mass or more, more preferably 70% by mass or more, and further preferably 80% by mass or more, based on the total mass of the composition. The content of the metal particles may be 98% by mass or less, 95% by mass or less, or 90% by mass or less, based on the total mass of the composition.

[0056] From the viewpoint of better thermal conductivity of the cured product, the content of the metal particles is preferably 20% by volume or more, more preferably 30% by volume or more, and further preferably 40% by volume or more, based on the total volume of the composition. The content of the metal particles may be 90% by volume or less, 80% by volume or less, or 70% by volume or less, based on the total volume of the composition.

[0057] The composition may further contain other polymerizable compounds copolymerizable with the above-mentioned (meth)acrylic polymer for the purpose of adjusting the physical properties of the composition and the cured product.

[0058] Other polymerizable compounds may be, for example, compounds having one (meth)acryloyl group. Such compounds may be, for example, alkyl (meth)acrylates. Other polymerizable compounds may be compounds having, in addition to one (meth)acryloyl group, an aromatic hydrocarbon group, a group containing a polyoxyalkylene chain, a group containing a heterocycle, an alkoxy group, a phenoxy group, a group containing a silyl group, a group containing a siloxane bond, a halogen atom, a hydroxyl group, a carboxyl group, an amino group, or an epoxy group. By having the composition further contain a compound having one (meth)acryloyl group, the physical properties of the cured product, such as thermal conductivity, can be adjusted.

[0059] The alkyl group (alkyl moiety other than the (meth)acryloyl group) in the alkyl (meth)acrylate may be linear, branched, or cyclic. The number of carbon atoms in the alkyl group may be 1 or more, 3 or more, 5 or more, or 6 or more, and may be 30 or less, 24 or less, 20 or less, 18 or less, 14 or less, or 12 or less. The number of carbon atoms in the alkyl group may be, for example, 1 to 30, 1 to 24, 3 to 18, 5 to 14, or 6 to 12, or 1 to 11, 1 to 8, 1 to 6, or 1 to 4, or 12 to 30, 12 to 28, 12 to 24, 12 to 22, 12 to 18, or 12 to 14.

[0060] Examples of the alkyl (meth)acrylate having a linear alkyl group include alkyl (meth)acrylate having a linear alkyl group having 1 to 11 carbon atoms and alkyl (meth)acrylate having a linear alkyl group having 12 to 30 carbon atoms. Examples of the alkyl (meth)acrylate having a linear alkyl group having 1 to 11 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, and undecyl (meth)acrylate. Examples of the alkyl (meth)acrylate having a linear alkyl group having 12 to 30 carbon atoms include dodecyl (meth)acrylate (lauryl (meth)acrylate), tetradecyl (meth)acrylate, hexadecyl (meth)acrylate (cetyl (meth)acrylate), octadecyl (meth)acrylate (stearyl (meth)acrylate), behenyl (meth)acrylate (behenyl (meth)acrylate), lignoceryl (meth)acrylate, hexadecyl (meth)acrylate, and dioctadecyl (meth)acrylate.

[0061] Examples of the alkyl (meth)acrylate having a branched alkyl group include alkyl (meth)acrylate having a branched alkyl group having 1 to 11 carbon atoms and alkyl (meth)acrylate having a branched alkyl group having 12 to 30 carbon atoms. Examples of the alkyl (meth)acrylate having a branched alkyl group having 1 to 11 carbon atoms include sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, isoamyl (meth)acrylate, isopentyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and the like. Examples of the alkyl (meth)acrylate having a branched alkyl group having 12 to 30 carbon atoms include isomyristyl (meth)acrylate, 2-propylheptyl (meth)acrylate, isoundecyl (meth)acrylate, isododecyl (meth)acrylate, isotridecyl (meth)acrylate, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, isostearyl (meth)acrylate, and decyltetradecyl (meth)acrylate.

[0062] Examples of the alkyl (meth)acrylate having a cyclic alkyl group (cycloalkyl group) include cyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, terpene (meth)acrylate, and dicyclopentanyl (meth)acrylate.

[0063] Examples of the compound having one (meth)acryloyl group and an aromatic hydrocarbon group include benzyl (meth)acrylate and the like.

[0064] Examples of the compound having one (meth)acryloyl group and a polyoxyalkylene chain-containing group include polyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, polybutylene glycol (meth)acrylate, and methoxypolybutylene glycol (meth)acrylate.

[0065] Examples of the compound having one (meth)acryloyl group and a heterocyclic ring-containing group include N-acryloyl methacrylate (ACMO) and tetrahydrofurfuryl (meth)acrylate.

[0066] Examples of the compound having one (meth)acryloyl group and an alkoxy group include 2-methoxyethyl acrylate and the like.

[0067] Examples of the compound having one (meth)acryloyl group and a phenoxy group include phenoxyethyl (meth)acrylate and the like.

[0068] Examples of the compound having one (meth)acryloyl group and a group containing a silyl group include 3-acryloxypropyltriethoxysilane, 10-methacryloxydecyltrimethoxysilane, 10-acryloxydecyltrimethoxysilane, 10-methacryloxydecyltriethoxysilane, and 10-acryloxydecyltriethoxysilane.

[0069] Examples of the compound having one (meth)acryloyl group and a group containing a siloxane bond include silicone (meth)acrylate and the like.

[0070] Examples of the compound having one (meth)acryloyl group and a halogen atom include (meth)acrylates having fluorine atoms. Examples of the (meth)acrylates having fluorine atoms include trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 1,1,1,3,3,3-hexafluoro-2-propyl (meth)acrylate, perfluoroethyl methyl (meth)acrylate, perfluoropropyl (meth)acrylate, perfluorobutyl methyl (meth)acrylate, perfluoropentyl methyl (meth)acrylate, perfluorohexyl methyl (meth)acrylate, perfluoroheptyl methyl (meth)acrylate, perfluorooctyl methyl (meth)acrylate, perfluorononyl methyl (meth)acrylate, perfluorodecyl methyl (meth)acrylate, perfluoroundecyl methyl (meth)acrylate, perfluorododecyl methyl (meth)acrylate, and perfluorooctyl methyl (meth)acrylate. methyl (meth)acrylate, perfluorotridecyl methyl (meth)acrylate, perfluorotetradecyl methyl (meth)acrylate, 2-(trifluoromethyl)ethyl (meth)acrylate, 2-(perfluoroethyl)ethyl (meth)acrylate, 2-(perfluoropropyl)ethyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 2-(perfluoropentyl)ethyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 2-(perfluoroheptyl)ethyl (meth)acrylate, 2-(perfluorooctyl)ethyl (meth)acrylate, 2-(perfluorononyl)ethyl (meth)acrylate, 2-(perfluorotridecyl)ethyl (meth)acrylate, 2-(perfluorotetradecyl)ethyl (meth)acrylate, and the like.

[0071] Examples of the compound having one (meth)acryloyl group and a hydroxyl group include hydroxyalkyl (meth)acrylates and hydroxyalkylcycloalkyl (meth)acrylates. Examples of hydroxyalkyl (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. Examples of hydroxyalkylcycloalkane (meth)acrylates include (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

[0072] Examples of the compound having a (meth)acryloyl group and a carboxyl group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, monohydroxyethyl acrylate phthalate (e.g., "ARONIX M5400" manufactured by TOAGOSEI CO., LTD.), and 2-acryloyloxyethyl succinate (e.g., "NK Ester A-SA" manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0073] In the case where the composition further contains a compound having a (meth)acryloyl group, from the viewpoint of better thermal conductivity of the cured product, the compound having a (meth)acryloyl group preferably includes a compound having a (meth)acryloyl group and a carboxyl group. Based on the total mass of the compound having a (meth)acryloyl group, the content of the compound having a (meth)acryloyl group and a carboxyl group is preferably 8% by mass or less, more preferably 6% by mass or less, and further preferably 4% by mass or less. Based on the total mass of the compound having a (meth)acryloyl group, the content of the compound having a (meth)acryloyl group and a carboxyl group may be 1% by mass or more.

[0074] Examples of the compound having one (meth)acryloyl group and an amino group include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, and N,N-diethylaminopropyl (meth)acrylate.

[0075] Examples of the compound having one (meth)acryloyl group and an epoxy group include glycidyl (meth)acrylate, α-ethyl glycidyl (meth)acrylate, α-n-propyl glycidyl (meth)acrylate, α-n-butyl glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4,5-epoxypentyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, α-ethyl (meth)acrylate-6,7-epoxyheptyl, 3-methyl-3,4-epoxybutyl (meth)acrylate, 4-methyl-4,5-epoxypentyl (meth)acrylate, 5-methyl-5,6-epoxyhexyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and α-ethyl (meth)acrylate-β-methylglycidyl.

[0076] The compound having one (meth)acryloyl group may be a (meth)acrylic acid-based polymer having one (meth)acryloyl group at one end of a poly(meth)acrylate chain. An example of such a (meth)acrylic acid-based polymer is "MM110C" manufactured by KANEKA CORPORATION.

[0077] The content of other polymerizable compounds may be 1% by mass or more, 2% by mass or more, 3% by mass or more, 4% by mass or more, or 15% by mass or less, 10% by mass or less, 8% by mass or less, or 7% by mass or less, based on the total mass of the composition.

[0078] The content of other polymerizable compounds may be 35 parts by mass or more, 40 parts by mass or more, 45 parts by mass or more, or 50 parts by mass or more, or 90 parts by mass or less, 80 parts by mass or less, 70 parts by mass or less, or 60 parts by mass or less, relative to a total of 100 parts by mass of the content of the polymerizable components.

[0079] The composition may further contain a polymerization initiator. The polymerization initiator may be, for example, a thermal polymerization initiator that generates free radicals by heat, a photopolymerization initiator that generates free radicals by light, etc. The polymerization initiator is preferably a thermal polymerization initiator.

[0080] When the composition contains a thermal polymerization initiator, a cured product of the composition can be obtained by applying heat to the composition. In this case, the composition can be a composition that is cured by heating preferably at 105°C or higher, more preferably at 110°C or higher, and further preferably at 115°C or higher, for example, a composition that is cured by heating at 200°C or lower, 190°C or lower, or 180°C or lower. The heating time when the composition is heated can be appropriately selected according to the composition composition so that the composition is suitably cured.

[0081] As the thermal polymerization initiator, there can be mentioned azo compounds, organic peroxides, etc. As the azo compound, there can be mentioned azobisisobutyronitrile, azobis-4-methoxy-2,4-dimethylvaleronitrile, azobiscyclohexane-1-carbonitrile, azobisbenzoyl, etc. As the organic peroxide, there can be mentioned benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, di-tert-butyl peroxyhexahydroterephthalate, tert-butyl peroxy-2-ethylhexanoate, 1,1-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butylperoxyisopropyl carbonate, etc. As for the thermal polymerization initiator, they can be used alone or in combination of two or more.

[0082] When the composition contains a photopolymerization initiator, for example, a cured product of the composition can be obtained by irradiating the composition with light (for example, light having at least a partial wavelength of 200 to 400 nm (ultraviolet light)). The light irradiation conditions can be appropriately set depending on the type of the photopolymerization initiator.

[0083] The photopolymerization initiator may be, for example, a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and the like.

[0084] Examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one (for example, "Irgacure 651" manufactured by BASF), and anisole methyl ether. Examples of the acetophenone-based photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone (e.g., “Irgacure 184” manufactured by BASF), 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (e.g., “Irgacure 2959” manufactured by BASF), 2-hydroxy-2-methyl-1-phenyl-propane-1-one (e.g., “Irgacure 1173” manufactured by BASF), and methoxyacetophenone.

[0085] Examples of α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropane-1-one. Examples of aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0086] Examples of benzoin-based photopolymerization initiators include benzoin. Examples of benzyl-based photopolymerization initiators include benzyl. Examples of benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone, and the like. Examples of ketal-based photopolymerization initiators include benzyl dimethyl ketal, and the like. Examples of thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0087] Examples of the acylphosphine oxide-based photopolymerization initiator include bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)(2,4,4-trimethylpentyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-n-butylphosphine oxide, bis(2,6-dimethoxybenzoyl)-(2-methylpropane-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropane-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-tert-butylphosphine oxide, bis(2,6-dimethoxybenzoyl)cyclohexylphosphine oxide, bis(2,6-dimethoxybenzoyl)octylphosphine oxide, bis(2-methoxybenzoyl)(2,4,4-trimethylpentyl)phosphine oxide, bis(2-methoxybenzoyl)(1-methylpropane-1-yl)phosphine oxide, bis(2-methoxybenzoyl)(1-methylpropane-1-yl)phosphine oxide, bis(2,6-diethoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, bis(2,6-diethoxybenzoyl)(1-methylpropane-1-yl)phosphine oxide, bis(2,6-dibutoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, bis(2,4-dimethoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)(2,4-dipentyloxyphenyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)benzylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2- Phenylpropylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylethylphosphine oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diisopropylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-4-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,3,5,6-tetramethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,3,5,6-tetramethylphenylphosphine oxide, 2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)isobutylphosphine oxide, 2,6-dimethoxybenzoyl-2,4,6-trimethylbenzoyl-n-butylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dibutoxyphenylphosphine oxide, 1,10-bis[bis(2,4,6-trimethylbenzoyl)phosphine oxide]decane, tri(2-methylbenzoyl)phosphine oxide, and the like.

[0088] The above-mentioned photopolymerization initiators can be used alone or in combination of two or more.

[0089] From the viewpoint of suitably performing polymerization, the content of the polymerization initiator is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, further preferably 0.1 parts by mass or more, and particularly preferably 0.5 parts by mass or more, relative to a total of 100 parts by mass of the content of the polymerizable components. From the viewpoint of keeping the molecular weight of the polymer in the cured product of the composition within a suitable range and suppressing decomposition products, the content of the polymerization initiator is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and further preferably 3 parts by mass or less, relative to a total of 100 parts by mass of the content of the polymerizable components.

[0090] The composition may also contain a copolymer (hereinafter also referred to as an "acrylic copolymer") containing methyl (meth)acrylate and an alkyl (meth)acrylate having an alkyl group with 2 to 12 carbon atoms (hereinafter also referred to as a "C2-C12 (meth)acrylate alkyl ester") as monomer units. However, the acrylic copolymer does not have a (meth)acryloyl group.

[0091] The content of methyl (meth)acrylate contained in the acrylic copolymer may be 5% by mass or more, 10% by mass or more, 13% by mass or more, or 15% by mass or less, or 70% by mass or less, or 60% by mass or less, or 50% by mass or less, or 40% by mass or less, or 35% by mass or less, or 30% by mass or less, or 25% by mass or less, based on the total mass of the monomer units contained in the acrylic copolymer (hereinafter, also referred to as the "total mass of the monomer units").

[0092] The number of carbon atoms in the alkyl group of the C2-C12 (meth)acrylic acid alkyl ester may be 3 or more, 8 or less, 7 or less, or 6 or less. The alkyl group may be linear, branched, or cyclic.

[0093] Specific examples of the case where the alkyl group in the C2-C12 (meth)acrylic acid alkyl ester is linear include ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, and lauryl (meth)acrylate. Specific examples of the case where the alkyl group in the C2-C12 (meth)acrylic acid alkyl ester is branched include isopropyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, isopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate. As a specific example of the case where the alkyl group in the C2-C12 (meth)acrylic acid alkyl ester is cyclic (cycloalkyl), cyclohexyl (meth)acrylate can be mentioned.

[0094] The above-mentioned C2-C12 alkyl (meth)acrylates can be used alone or in combination of two or more.

[0095] The content of C2-C12 (meth)acrylic acid alkyl ester contained in the acrylic copolymer can be 30 mass% or more, 50 mass% or more, 60 mass% or more, 70 mass% or more, or 75 mass% or less, based on the total mass of the monomer units, or 95 mass% or less, 90 mass% or less, or 85 mass% or less.

[0096] The acrylic copolymer may contain only methyl (meth)acrylate and C2-C12 alkyl (meth)acrylate as monomer units, or may contain other monomer units copolymerizable with methyl (meth)acrylate and C2-C12 alkyl (meth)acrylate. Examples of other monomer units include carboxyl group-containing monomers, hydroxyl group-containing monomers, isocyanate group-containing monomers, amino group-containing monomers, and epoxy group-containing monomers.

[0097] Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. Examples of isocyanate-containing monomers include 2-methacryloyloxyethyl isocyanate and 2-acryloyloxyethyl isocyanate. Examples of amino-containing monomers include N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, and N,N-diethylaminopropyl (meth)acrylate. Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, α-ethyl glycidyl (meth)acrylate, α-n-propyl glycidyl (meth)acrylate, α-n-butyl glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 4,5-epoxypentyl (meth)acrylate, 6,7-epoxyheptyl (meth)acrylate, 6,7-epoxyheptyl α-(meth)acrylate, 3-methyl-3,4-epoxybutyl (meth)acrylate, 4-methyl-4,5-epoxypentyl (meth)acrylate, 5-methyl-5,6-epoxyhexyl (meth)acrylate, β-methylglycidyl (meth)acrylate, and β-methylglycidyl α-(meth)acrylate. The content of other monomer units may be 10% by mass or less, 5% by mass or less, 3% by mass or less, or 1% by mass or less based on the total mass of the monomer units.

[0098] The acrylic copolymer may be an alternating copolymer, a block copolymer or a random copolymer comprising a methyl (meth)acrylate unit, a C2-C12 alkyl (meth)acrylate unit and other monomer units as required, and is preferably a block copolymer.

[0099] The block copolymer may have a block containing a methyl (meth)acrylate unit (hereinafter, also referred to as a "first block") and a block containing a C2-C12 alkyl (meth)acrylate (hereinafter, also referred to as a "second block").

[0100] The content of methyl (meth)acrylate contained in the first block may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the monomer units contained in the first block. For example, the first block may be a polymethyl (meth)acrylate block containing only methyl (meth)acrylate as a monomer unit.

[0101] The content of C2-C12 (meth) alkyl acrylate contained in the second block may be 90% by mass or more, 95% by mass or more, or 99% by mass or more, based on the total mass of the monomer units contained in the second block. The second block may contain one selected from C2-C12 (meth) alkyl acrylates as a monomer unit, or may contain two or more. For example, the second block may be a poly (meth) acrylate n-butyl ester block containing only n-butyl (meth) acrylate as a monomer unit.

[0102] The block copolymer may be a diblock copolymer in which a first block and a second block are bonded in sequence, or may be a triblock copolymer in which a first block, a second block and a first block are bonded in sequence.

[0103] The content of the acrylic copolymer may be 0.05 mass % or more, 0.1 mass % or more, or 0.15 mass % or less, or 1 mass % or less, 0.7 mass % or less, or 0.5 mass % or less, based on the total mass of the composition.

[0104] The content of the acrylic copolymer may be 1 part by mass or more, 2 parts by mass or more, or 3 parts by mass or more, or 10 parts by mass or less, 7 parts by mass or less, or 6 parts by mass or less, based on 100 parts by mass of the total content of the polymerizable components.

[0105] From the viewpoint of improving the thermal reliability of the cured product, the composition may further contain an antioxidant, such as a phenolic antioxidant, a benzophenone antioxidant, a benzoate antioxidant, a hindered amine antioxidant, a benzotriazole antioxidant, etc., preferably a phenolic antioxidant.

[0106] The phenolic antioxidant has, for example, a hindered phenol structure (hindered phenol ring). The hindered phenol structure (hindered phenol ring) may be, for example, a structure in which a tert-butyl group is bonded to one or both of the ortho positions of the hydroxyl group in the phenolic ring. The phenolic antioxidant has one or more such hindered phenol rings, preferably two or more, more preferably three or more, and even more preferably four or more.

[0107] The content of the antioxidant may be 0.1 mass % or more, 0.2 mass % or more, or 0.3 mass % or less, or 5 mass % or less, 3 mass % or less, 1 mass % or less, or 0.7 mass % or less, based on the total mass of the composition.

[0108] The composition may further contain other additives as required. Other additives include, for example, thixotropic agents, surface treatment agents, dispersants, curing accelerators, colorants, crystal nucleating agents, thermal stabilizers, foaming agents, flame retardants, damping agents, dehydrating agents, flame retardant aids (such as metal oxides), etc. Based on the total mass of the composition, the content of other additives may be 0.1% by mass or more, or 1% by mass or less.

[0109] The composition is preferably liquid at 25° C. Thus, it can be appropriately applied to the surface of an object such as a component that becomes a heat source or a cooling component, and the adhesion to the applied surface can be improved. The composition may be solid at 25° C. In this case, it is preferably heated (for example, at 50° C. or above) to become liquid.

[0110] [Combination group]

[0111] The above-mentioned composition can be in the state of a plurality of liquid compositions (composition groups). The composition group of one embodiment is a composition group having a first liquid containing an oxidizing agent and a second liquid containing a reducing agent. At least one of the first liquid and the second liquid contains the above-mentioned (meth)acrylic polymer. In addition, at least one of the first liquid and the second liquid contains the above-mentioned metal particles. By mixing the first liquid and the second liquid, the oxidizing agent and the reducing agent react to generate free radicals, and polymerization of polymerizable components such as the (meth)acrylic polymer is carried out. According to the composition group of this embodiment, by mixing the first liquid and the second liquid, a solidified product of the mixture of the first liquid and the second liquid can be immediately obtained. That is, according to the composition group, a solidified product of the composition can be quickly obtained.

[0112] In the composition set, preferably, the first liquid contains an oxidizing agent, a (meth)acrylic polymer, and metal particles, and the second liquid contains a reducing agent, a (meth)acrylic polymer, and metal particles.

[0113] The content of the (meth)acrylic acid polymer based on the total mass of the liquids constituting the composition set (for example, the total mass of the first liquid and the second liquid in the case of a two-liquid composition set) can be in the same range as the content of the (meth)acrylic acid polymer based on the total mass of the above-mentioned composition. The content of the metal particles contained in the composition set is also the same.

[0114] The oxidant contained in the first liquid has a role as a polymerization initiator (free radical polymerization initiator). The oxidant can be, for example, an organic peroxide or an azo compound. The organic peroxide can be, for example, a hydroperoxide, a peroxydicarbonate, a peroxyester, a peroxyketal, a dialkyl peroxide, a diacyl peroxide, etc. The azo compound can be AIBN (2, 2'-azobisisobutyronitrile), V-65 (azobisdimethylvaleronitrile), etc. The oxidant can be used alone or in combination of two or more.

[0115] Examples of the hydroperoxide include diisopropylbenzene hydroperoxide and cumene hydroperoxide.

[0116] Examples of the peroxydicarbonate include di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, di-2-ethoxymethoxyperoxydicarbonate, di(2-ethylhexylperoxy)dicarbonate, dimethoxybutylperoxydicarbonate, and di(3-methyl-3-methoxybutylperoxy)dicarbonate.

[0117] Examples of the peroxyesters include cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxytrimethylacetate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane ... tert-Butyl peroxy-2-ethylhexanoate, tert-Hexyl peroxy-2-ethylhexanoate, tert-Butyl peroxy-2-ethylhexanoate, tert-Butyl peroxyisobutyrate, 1,1-bis(tert-butylperoxy)cyclohexane, tert-Butyl peroxy-3,5,5-trimethylhexanoate, tert-Butyl peroxylaurate, 2,5-dimethyl-2,5-di(m-toluoylperoxy)hexane, tert-Hexyl peroxybenzoate, tert-Butyl peroxyacetate, etc.

[0118] Examples of the peroxyketal include 1,1-bis(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclododecane, and 2,2-bis(tert-butylperoxy)decane.

[0119] Examples of the dialkyl peroxide include α,α′-bis(tert-butylperoxy)diisopropylbenzene, diisopropylphenyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and tert-butylisopropylphenyl peroxide.

[0120] Examples of the diacyl peroxide include isobutyl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic peroxide, benzoyl peroxytoluene, and benzoyl peroxide.

[0121] From the viewpoint of storage stability, the oxidizing agent is preferably a peroxide, more preferably a hydroperoxide, and still more preferably cumene hydroperoxide.

[0122] The content of the oxidant may be 0.1 mass % or more, 0.5 mass % or more, or 10 mass % or less, 5 mass % or less, or 3 mass % or less, based on the total mass of the liquid constituting the composition group.

[0123] The reducing agent contained in the second liquid may be, for example, a tertiary amine, a thiourea derivative, a transition metal salt, etc. As the tertiary amine, triethylamine, tripropylamine, tributylamine, N,N-dimethyl-p-toluidine, etc. may be mentioned. As the thiourea derivative, 2-mercaptobenzimidazole, methylthiourea, dibutylthiourea, tetramethylthiourea, ethylenethiourea, etc. may be mentioned. As the transition metal salt, cobalt naphthenate, copper naphthenate, vanadium acetylacetonate, etc. may be mentioned. The reducing agent may be used alone or in combination of two or more.

[0124] From the viewpoint of excellent curing speed, the reducing agent is preferably a thiourea derivative or a transition metal salt. For example, the thiourea derivative may be ethylenethiourea. From the same viewpoint, the transition metal salt is preferably vanadyl acetylacetonate.

[0125] The content of the reducing agent may be 0.05 mass % or more, 0.1 mass % or more, or 0.3 mass % or less, or 5 mass % or less, or 3 mass % or less, or 1 mass % or less, based on the total mass of the liquid constituting the composition group.

[0126] The composition set may also contain other polymerizable compounds, acrylic copolymers, antioxidants and other additives that can be used in the above-mentioned composition. These components may be contained in one or both of the first liquid and the second liquid, or in a third liquid different from the first liquid and the second liquid. The content of these components based on the total mass of the liquid constituting the composition set may be the same as the range of the content of these components based on the total mass of the above-mentioned composition.

[0127] The cured product of the above-mentioned composition and the composition group has thermal conductivity and excellent heat resistance, and is therefore suitable for heat dissipation materials, pressure-sensitive adhesives, die bonding materials, structural adhesives, battery adhesives, stress relaxants, sealants, coatings, coatings and other uses, and is particularly suitable for use as a composition to form a heat dissipation material. Similarly, the cured product of the above-mentioned composition and the cured product of the mixture of the composition group have excellent heat resistance, and are therefore suitable for the above-mentioned purposes. Specifically, the cured product of the above-mentioned composition and the cured product of the composition group can be suitable for use as a heat dissipation material for semiconductor parts, and can be particularly suitable for use as a heat dissipation application for semiconductor packages used in personal computers, servers, base stations, etc.

[0128] [thing]

[0129] Next, an article having a cured product (hereinafter, also referred to as a "cured product") of the above-mentioned composition or composition group is described. An article of one embodiment has a heat source and a cured product in thermal contact with the heat source. Hereinafter, as a more specific example of the article, an electronic component is described as an example. Figure 1 This is a schematic cross-sectional view showing one embodiment of an electronic component including a cured product. Figure 1 The electronic component 1A shown includes a semiconductor wafer 21 as a heat source and a heat sink 22 as a heat dissipation unit.

[0130] The electronic component 1A includes a cured product 11 provided between a semiconductor wafer 21 and a heat sink 22. The cured product 11 is a cured product of the above-mentioned composition or a cured product of a mixture of the composition group.

[0131] Since the cured product 11 has thermal conductivity, the cured product 11 functions as a thermally conductive material (thermal interface material) in the electronic component 1A, and heat is conducted from the semiconductor wafer 21 to the heat sink 22. The heat is then dissipated from the heat sink 22 to the outside.

[0132] Since the cured product 11 has excellent heat resistance, degradation due to heat can be suppressed. Therefore, the heat generated from the semiconductor wafer 21 can be efficiently conducted to the heat sink 22 .

[0133] The cured product 11 can also be obtained by placing a liquid composition (composition group) between the semiconductor wafer 21 and the heat sink 22 and then curing it. Therefore, the generation of voids due to dripping and overflowing can be suppressed, and as a result, the cured product 11 can have excellent adhesion (adhesion to the surfaces of the semiconductor wafer 21 and the heat sink 22). In addition, the curing method and curing conditions of the composition can be adjusted according to the composition of the composition or the type of polymerization initiator.

[0134] exist Figure 1In the electronic component 1A described in the figure, the cured product 11 is arranged to be in direct contact with the semiconductor chip 21 and the heat sink 22, but the cured product 11 only needs to be in thermal contact with the heat source, and in another embodiment, it can be arranged to be in contact with the heat source (semiconductor chip) through other components.

[0135] Figure 2 This is a schematic cross-sectional view showing another embodiment of an electronic component including a cured product. Figure 2 The electronic component 1B shown is a processor including a semiconductor chip 21 as a heat source disposed on one side of a substrate 23 via a primer 24, a heat sink 22 as a heat dissipation portion, and a heat sink 25 disposed between the semiconductor chip 21 and the heat sink 22. A first cured product 11 is disposed between the semiconductor chip 21 and the heat sink 25 so as to be in contact with the semiconductor chip 21. A second cured product 11 is disposed between the heat sink 25 and the heat sink 22.

[0136] The substrate 23, the primer 24, and the heat sink 25 can be formed of materials commonly used in the technical field. For example, the substrate 23 can be a laminate substrate, the primer 24 can be formed of a resin such as epoxy resin, and the heat sink 25 can be a metal plate.

[0137] The first cured product 11 and the second cured product 11 are cured products of the above-mentioned curable composition or cured products of a mixture of the above-mentioned curable composition group. The first cured product 11 is in direct contact with the semiconductor wafer 21 as a heat source, but the second cured product 11 is in thermal contact with the semiconductor wafer 21 as a heat source via the first cured product 11 and the heat sink 25.

[0138] The first cured product 11 and the second cured product 11 have thermal conductivity, and therefore function as thermally conductive materials (thermal interface materials) in the electronic component 1B. That is, the first cured product 11 promotes heat conduction from the semiconductor chip 21 to the heat sink 25. In addition, the second cured product 11 promotes heat conduction from the heat sink 25 to the heat sink 22. Then, the heat is dissipated from the heat sink 22 to the outside.

[0139] The first cured product 11 and the second cured product 11 also have excellent heat resistance, so the first cured product 11 and the second cured product 11 can suppress thermal degradation. Therefore, the heat generated from the semiconductor wafer 21 can be more effectively conducted to the heat sink 25, and further, the heat can be more effectively conducted to the heat sink 22.

[0140] The first cured product 11 and the second cured product 11 can also be obtained by placing a liquid composition (composition group) between the semiconductor chip 21 and the heat sink 25, or between the heat sink 25 and the heat sink 22, and then curing. Therefore, in the electronic component 1B, it is possible to suppress the generation of voids due to dripping and overflowing of the composition (composition group), and as a result, the first cured product 11 and the second cured product 11 can have excellent adhesion (adhesion to the surface of the semiconductor chip 21, the heat sink 25 and / or the heat sink 22).

[0141] Example

[0142] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0143] In the examples and comparative examples, the following components were used.

[0144] (A-1) (meth)acrylic acid polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain ("RC200C" manufactured by KANEKA CORPORATION, weight average molecular weight: 18,000, viscosity at 23° C.: 530 Pa·s, Tg: −39° C.)

[0145] (A-2) (meth)acrylic acid polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain ("RC100C" manufactured by KANEKA CORPORATION, weight average molecular weight: 20,000, viscosity at 23° C.: 160 Pa·s, Tg: −50° C.)

[0146] (A-3) (meth)acrylic acid polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain ("RC310C" manufactured by KANEKA CORPORATION, weight average molecular weight: 30,000, viscosity at 23° C.: 760 Pa·s, Tg: −44° C.)

[0147] (A-4) (meth)acrylic acid polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain ("RC120C" manufactured by KANEKA CORPORATION, weight average molecular weight: 30,000, viscosity at 23° C.: 330 Pa·s, Tg: −50° C.)

[0148] (a-1) A compound represented by the following formula (a-1) (weight average molecular weight: 16,000, a mixture of integers of approximately 246±5 and approximately 105±5 in formula (a-1), viscosity at 25° C.: 55 Pa·s)

[0149]

[0150] In the formula (a-1), -r- is a symbol representing random copolymerization.

[0151] (B-1) scaly silver particles (“SILCOATAgC-221PA” manufactured by FUKUDA METAL FOIL & POWDER CO., LTD.), average particle size: 6.8 μm, BET specific surface area: 0.20 m 2 / g)

[0152] (B-2) scaly silver particles (“SILCOATAg C-2262” manufactured by FUKUDA METAL FOIL & POWDER CO., LTD.), average particle size: 5.3 μm, BET specific surface area: 0.1 to 0.4 m 2 / g)

[0153] (C-1) 2-Ethylhexyl acrylate ("AEH" manufactured by NIPPON SHOKUBAI CO., LTD.)

[0154] (C-2) Isodecyl acrylate ("FA111A" manufactured by Showa Denko Materials Co., Ltd.)

[0155] (C-3) 4-Hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0156] (C-4) N-Acryloylmethyl methacrylate ("ACMO" manufactured by KJ Chemicals Corporation)

[0157] (C-5) 2-Acryloyloxyethyl succinate ("NK Ester A-SA" manufactured by Shin-Nakamura Co., Ltd.)

[0158] (D-1) A triblock copolymer in which a polymethyl methacrylate block, a poly-n-butyl acrylate block and a polymethyl methacrylate block are sequentially bonded ("KURARITY (registered trademark) LA2270 manufactured by KURARAY CO., LTD.," methyl methacrylate content based on the total mass of the monomer units: 40% by mass, weight average molecular weight: about 50,000)

[0159] (D-2) A triblock copolymer in which a polymethyl methacrylate block, a poly-n-butyl acrylate block and a polymethyl methacrylate block are sequentially bonded ("KURARITY (registered trademark) LA2140 manufactured by KURARAY CO., LTD.," methyl methacrylate content based on the total mass of the monomer units: 20% by mass, weight average molecular weight: about 47,000)

[0160] (D-3) A triblock copolymer in which a polymethyl methacrylate block, a poly-n-butyl acrylate block and a polymethyl methacrylate block are sequentially bonded ("KURARITY (registered trademark) LA3710 manufactured by KURARAY CO., LTD.," methyl methacrylate content based on the total mass of the monomer units: 15% by mass, weight average molecular weight: 150,000)

[0161] (E) Phenol antioxidant ("Irganox 1010" manufactured by BASF Japan Ltd.)

[0162] (F) Thixotropic agent ("GARAMITE-7305" manufactured by BYK Chemie GmbH)

[0163] (G) Thixotropic agent ("FlOWLEN GW1500" manufactured by KYOEISHA CHEMICAL Co., LTD.)

[0164] [Production of Composition and Cured Product]

[0165] The components were mixed in the proportions shown in Table 1 to obtain the compositions of the examples. The compositions of the examples were filled in 10 cm × 10 cm × 0.5 mm templates (SUS plate), covered with a SUS plate, and then heated at 135° C. for 15 minutes to cure, thereby obtaining a cured product with a thickness of 0.5 mm.

[0166] [Evaluation of heat resistance]

[0167] The cured product with a thickness of 0.5 mm was cut into 3 cm x 3 cm pieces, and the weight (initial weight) was measured, and then placed in a 150°C thermostat, taken out after 1000 hours, and the weight was measured again (weight after 1000 hours). The weight loss was calculated by the following formula.

[0168] Weight loss (%) = {(initial weight - weight after 1000 hours) / initial weight} × 100

[0169] [Measurement of thermal conductivity]

[0170] The cured product with a thickness of 0.5 mm was cut into squares of 10 mm × 10 mm × 0.5 mm, and blackened by graphite spraying, and then the thermal diffusivity at 25° C. was measured by a xenon flash method (“LFA447nanoflash” manufactured by NETZSCH-Geratebau GmbH, Selb / Bayern). The thermal conductivity in the thickness direction of the cured product was calculated based on the following formula, based on the product of this value, the density measured by the Archimedean method, and the specific heat at 25° C. measured by a differential scanning calorimeter (“DSC250” manufactured by TA Instruments Japan Inc.).

[0171] Thermal conductivity λ(W / (m·K))=α×ρ×Cp

[0172] α: Thermal diffusivity (m 2 / s)

[0173] ρ: Density (kg / cm 3 )

[0174] Cp: ​​Specific heat (capacity) (kJ / (kg·K))

[0175] [Determination of elongation at break and tensile modulus]

[0176] The elongation at break and tensile modulus of the cured product at 25° C. were measured using a tensile tester ("Autograph EZ-TEST EZ-S" manufactured by SHIMADZU CORPORATION). The measurement was performed in accordance with JIS K7161 on a cured product having a shape of 0.5 mm (thickness) × 5 mm (width) × 30 mm (length) under the conditions of a chuck distance of 20 mm and a tensile speed of 5 mm / min.

[0177] Tables 1 to 3 show the results of measuring various physical properties of the cured products of the compositions of the respective Examples.

[0178] [Table 1]

[0179]

[0180] [Table 2]

[0181]

[0182] [Table 3]

[0183]

[0184] Explanation of symbols

[0185] 1A, 1B-electronic parts, 11-cured product of the composition, 21-semiconductor chip (heat source), 22-heat sink, 23-substrate, 24-primer, 25-heat sink.

Claims

1. A composition comprising: A (meth)acrylic polymer having (meth)acryloyl groups at both ends of a poly(meth)acrylate chain; and Metal particles.

2. The composition according to claim 1, wherein The glass transition temperature of the (meth)acrylic polymer is -40°C or lower.

3. The composition according to claim 1, wherein The (meth)acrylic acid-based polymer has a weight average molecular weight of 19,000 or more.

4. The composition according to claim 2, wherein The (meth)acrylic acid-based polymer has a viscosity of 200 Pa·s or more at 23°C.

5. The composition according to any one of claims 1 to 4, further comprising a compound having one (meth)acryloyl group, The compound having one (meth)acryloyl group includes a compound having one (meth)acryloyl group and a carboxyl group, The content of the compound having one (meth)acryloyl group and a carboxyl group is 8% by mass or less based on the total mass of the compound having one (meth)acryloyl group.

6. The composition according to any one of claims 1 to 4, wherein The metal particles are silver particles. The composition according to claim 6 , which is used to form a heat dissipation material. 8 . A cured product, which is a cured product of the composition according to claim 1 .

9. An article having: heat source; and The cured product according to claim 8 in thermal contact with the heat source.

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