Two-pack curable composition and cured product

Abstract

A two-part curable composition containing: a liquid A containing a compound having one (meth) acrylate group in one molecule, a compound having two or more (meth) acrylate groups in one molecule, a dispersant, a thiourea compound represented by formula (a), and a thermally conductive filler; and a solution B containing a polymerization initiator, a dispersant, a plasticizer, and a thermally conductive filler, in formula (a), RA represents a linear or branched aliphatic hydrocarbon group having 8 to 18 carbon atoms, and RB1, RB2, and RB3 each independently represent a linear or branched aliphatic hydrocarbon group having 8 to 18 carbon atoms, or a hydrogen atom.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a two-liquid curable composition and a cured product. BACKGROUND

[0002] In recent years, electronic devices such as personal computers, mobile phones, and PDAs (Personal Digital Assistants), lighting and display devices such as LEDs (light emitting diodes) and ELs (Electronic Luminescent), and the like have significantly improved performance due to significant performance improvements in arithmetic elements or light emitting elements. Along with such performance improvements in arithmetic elements and light emitting elements, the amount of heat generated has also significantly increased, and how to dissipate heat in electronic devices, lighting, and display devices has become an important issue. As a heat countermeasure, a countermeasure of providing a TIM (Thermal Interface Material) between a heat generating body and a heat sink to transfer heat generated by the arithmetic elements and the light emitting elements to the heat sink without loss and dissipate the heat through the heat sink has been taken. As the heat sink, for example, a heat sink or the like is known, and as the heat generating body, for example, a CPU (Central Processing Unit), an LSI (Large Scale Integration), or the like is known. As a material generally used for TIMs, a heat sink sheet, a thermally conductive grease, a gap filler, and the like are known, and a gap filler that is initially paste-like, solidifies after being applied, and becomes a solid has attracted attention.

[0003] As a gap filler excellent in flexibility, shape stability, and thermal conductivity, for example, International Publication No. 2020 / 149193 describes a curable composition containing: a compound (A) having one (meth)acrylate group in one molecule, a compound (B) having two or more (meth)acrylate groups in one molecule, a polymerization initiator (C), a dispersant (D), and a thermally conductive filler (E) containing zinc oxide. SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] An object of one embodiment of the present disclosure is to provide a two-liquid curable composition having excellent curability, and in which the rate of increase in viscosity after mixing of the A liquid and the B liquid is suppressed, and a cured product thereof.

[0006] MEANS FOR SOLVING THE PROBLEMS

[0007] The present disclosure includes the following embodiments.

[0008] <1>

[0009] A two-liquid type curable composition comprising:

[0010] An A liquid containing a compound having one (meth)acrylate group in one molecule, a compound having two or more (meth)acrylate groups in one molecule, a dispersant, a thiourea compound represented by the following formula (a), and a thermally conductive filler; and

[0011] A B liquid containing a polymerization initiator, a dispersant, a plasticizer, and a thermally conductive filler.

[0012] [Chemical Formula 1]

[0013]

[0014] In formula (a), R A represents an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms and being linear or branched, R B1 , R B2 , and R B3 each independently represents an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms and being linear or branched, or a hydrogen atom.

[0015] <2>

[0016] The two-liquid type curable composition according to <1>, wherein, in the thiourea compound represented by the formula (a), R B1 is an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms and being linear or branched.

[0017] <3>

[0018] The two-liquid type curable composition according to <1> or <2>, wherein the content of the thiourea compound represented by the formula (a) is 2.00 parts by mass or more and 20.00 parts by mass or less, with respect to 100 parts by mass of the compound having one (meth)acrylate group in one molecule.

[0019] <4>

[0020] The two-liquid type curable composition according to any one of <1> to <3>, wherein the B liquid contains a compound having one (meth)acrylate group in one molecule.

[0021] <5>

[0022] A cured product of the two-liquid type curable composition according to any one of <1> to <4>.

[0023] Effects of the Invention

[0024] According to one embodiment of the present disclosure, there is provided a two-liquid curable composition or a cured product thereof, which has excellent curability and in which the rate of increase in viscosity after mixing of a liquid A and a liquid B is suppressed. DETAILED DESCRIPTION

[0025] Hereinafter, a two-liquid curable composition and a cured product thereof according to the present disclosure will be described in detail.

[0026] In the present disclosure, “~” indicating a numerical range means a range including the values recited as the upper limit and the lower limit, respectively. In addition, in the case where only the upper limit value unit is recited in the numerical range indicated by “~”, it means that the lower limit value is also the same unit.

[0027] In the present disclosure, in the case where a plurality of substances corresponding to each component is present in the composition, unless otherwise specified, the content or the amount of each component in the composition means the total content or the total amount of the plurality of substances present in the composition.

[0028] In the present disclosure, in the case where a numerical range is recited in stages, the upper limit value or the lower limit value recited in a certain numerical range can be replaced with the upper limit value or the lower limit value of another numerically recited range.

[0029] In the numerical range recited in the present disclosure, the upper limit value or the lower limit value recited in a certain numerical range can also be replaced with the value shown in the examples.

[0030] In the present disclosure, “(meth)acrylate” is a term used as a concept including both acrylate and methacrylate.

[0031] In the present disclosure, in the case where a plurality of each component is present in the composition, unless otherwise specified, each component in the composition means the total amount of the corresponding plurality of substances present in the composition.

[0032] In the present disclosure, a combination of two or more preferred modes is a more preferred mode.

[0033] In the present disclosure, “JIS” is an abbreviation for Japanese Industrial Standards.

[0034] (Two-liquid curable composition)

[0035] The two-liquid curable composition according to the present disclosure contains: an A liquid containing a compound having one (meth)acrylate group in one molecule (hereinafter also referred to as "compound A"), a compound having two or more (meth)acrylate groups in one molecule (hereinafter also referred to as "compound B"), a dispersant, a thiourea compound represented by the following formula (a) (hereinafter also referred to as "specific thiourea compound"), and a thermally conductive filler; and a B liquid containing a polymerization initiator, a dispersant, a plasticizer, and a thermally conductive filler.

[0036] The two-liquid curable composition according to the present disclosure has excellent curability, and the viscosity increase rate after mixing the A liquid and the B liquid is suppressed, by having the above structure. The reason for exerting this effect is presumed as follows.

[0037] In the two-liquid curable composition which can be applied to a gap filler, a reducing agent has been added in the past from the viewpoint of promoting the decomposition of a polymerization initiator and making the polymerization reaction proceed easily, and the like. However, when the two-liquid curable composition is cured to form a cured product, since it is sometimes necessary to wait for a certain period of time until the coating is performed after the A liquid and the B liquid are mixed, it is not preferable for the viscosity to immediately increase after the mixing. Therefore, it is required to suppress the rate of the viscosity increase after the mixing of the A liquid and the B liquid. Specifically, it is required that the time required for the viscosity to double (so-called pot life) after the mixing of the A liquid and the B liquid is long.

[0038] On the other hand, it is not preferable for the two-liquid curable composition to take too long time until curing, that is, excellent curability is required. The pot life of the two-liquid curable composition is too long to cause a decrease in curability, and therefore from this viewpoint, it is required that the pot life is not too long.

[0039] From the above viewpoint, for example, the pot life is preferably 30 minutes to 120 minutes.

[0040] On the contrary, the two-liquid curable composition according to the present disclosure contains a thiourea compound represented by the following formula (a) (specific thiourea compound) as a reducing agent. The specific thiourea compound has an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms in a straight chain or a branched chain in the chemical structure, and by the presence of this aliphatic hydrocarbon group, the action of promoting the decomposition of a polymerization initiator is moderately adjusted. As a result, it can be considered that while maintaining excellent curability, the viscosity increase rate after the mixing of the A liquid and the B liquid is suppressed, and the pot life becomes long.

[0041] Hereinafter, each component contained in the two-liquid curable composition according to the present disclosure will be described.

[0042] A liquid

[0043] The two-liquid curable composition according to the present disclosure contains a liquid A containing a compound having one (meth)acrylate group in one molecule (compound A), a compound having two or more (meth)acrylate groups in one molecule (compound B), a dispersant, a thiourea compound represented by the following formula (a), and a thermally conductive filler.

[0044] << Compound having one (meth)acrylate group in one molecule >>

[0045] The liquid A contains a compound having one (meth)acrylate group in one molecule (compound A).

[0046] As the compound A, there is no particular limitation, and for example, a linear, branched, or cyclic alkyl (meth)acrylate or the like can be exemplified. From the viewpoint of taking into account heat resistance and softness of the obtained cured product, as the compound A, a linear or branched alkyl (meth)acrylate is preferred, and more preferably a compound represented by the following general formula (1) is contained.

[0047] [Chemical Formula 2]

[0048]

[0049] In formula (1), R 1 represents an alkyl group having 1 to 50 carbon atoms, R 2 represents a hydrogen atom or a methyl group.

[0050] In formula (1), R 1 The alkyl group in R 1 may be linear, and may be branched. In addition, the alkyl group can have a substituent.

[0051] As the substituent, for example, a carboxyl group, a hydroxyl group, an amino group, an aryl group, a heterocyclic group, or the like can be exemplified.

[0052] From the viewpoint of taking into account heat resistance and softness, the total number of carbon atoms of the alkyl group in R 1 is preferably 2 to 30, more preferably 5 to 25, further preferably 10 to 25, and particularly preferably the total number of carbon atoms is 12 to 24. As R 1Examples of the alkyl group in the alkyl group having 1 to 30 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, cyclobutyl, n-pentyl, isopentyl, sec-pentyl, t-pentyl, neopentyl, 2-methylbutyl, 1,2-dimethylpropyl, 1-ethylpropyl, cyclopentyl, n-hexyl, isohexyl, sec-hexyl, t-hexyl, neohexyl, 2-methylpentyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, 1-ethylbutyl, cyclohexyl, n-heptyl, isoheptyl, sec-heptyl, t-heptyl, neheptyl, cycloheptyl, n-octyl, iso-octyl, sec-octyl, t-octyl, neo-octyl, 2-ethylhexyl, cyclo-octyl, n-nonyl, iso-nonyl, sec-nonyl, t-nonyl, ne-nonyl, cyclo-nonyl, n-decyl, iso-decyl, sec-decyl, t-decyl, ne-decyl, cyclo-decyl, n-undecyl, cyclo-undecyl, n-dodecyl, cyclo-dodecyl, norbornyl, bornyl, menthyl, isobornyl, and adamantyl, and the like.

[0053] Here, when the above alkyl group has a substituent group having a carbon atom, the total number of carbon atoms refers to the total number of carbon atoms including the number of carbon atoms of the substituent group.

[0054] From the viewpoint of balancing heat resistance and flexibility, in the formula (1), R 1 It is preferable that R is a linear or branched alkyl group having a total of 2 to 30 carbon atoms, or a linear or branched alkyl group having a total of 2 to 30 carbon atoms with a substituent group; it is more preferable that R is a linear or branched alkyl group having a total of 2 to 25 carbon atoms, or a linear or branched alkyl group having a total of 2 to 25 carbon atoms with a hydroxyl group; it is further preferable that R is a linear or branched alkyl group having a total of 12 to 24 carbon atoms.

[0055] As the compound A, for example, lauryl (meth)acrylate, stearyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate can be exemplified.

[0056] R 2 It is preferable that R is a linear or branched alkyl group having a total of 2 to 30 carbon atoms, or a linear or branched alkyl group having a total of 2 to 30 carbon atoms with a substituent group; it is more preferable that R is a linear or branched alkyl group having a total of 2 to 25 carbon atoms, or a linear or branched alkyl group having a total of 2 to 25 carbon atoms with a hydroxyl group; it is further preferable that R is a linear or branched alkyl group having a total of 12 to 24 carbon atoms.

[0057] -Content-

[0058] As the content of the compound A, it is preferable that it is 1 to 12 mass% with respect to the total mass of the A liquid, and it is more preferable that it is 2 to 10 mass%.

[0059] The A liquid can contain one kind of compound A alone, or can contain two or more kinds of compound A.

[0060] Compound A is preferably a monomer having a molecular weight of less than 1000.

[0061] In the present disclosure, a monomer refers to a polymerizable compound having a molecular weight of less than 1000.

[0062] << Compound having two or more (meth)acrylate groups in one molecule >>

[0063] A liquid contains a compound (compound B) having two or more (meth)acrylate groups in one molecule.

[0064] As the compound B, for example, (meth)acrylates having a linear or branched alkylene group can be exemplified. As the compound B, for example, hexanediol di(meth)acrylate, butanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate), ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, and the like can be exemplified.

[0065] As the compound B, from the viewpoint of balancing heat resistance and softness, a compound having two or three (meth)acrylate groups in one molecule is preferred, a compound having two (meth)acrylate groups in one molecule is more preferred, and a compound represented by the following formula (2) is further preferred.

[0066] [Chemical Formula 3]

[0067]

[0068] In formula (2), R B1 represents an alkylene group having 1 to 5 carbon atoms, R B2 and R B3 each independently represents a hydrogen atom or a methyl group, and n represents an integer of 4 or more.

[0069] The alkylene group having 1 to 5 carbon atoms represented by R B1 may be linear or branched.

[0070] From the viewpoint of softness, as the alkylene group represented by R B1 , an alkylene group having 2 to 5 carbon atoms which is linear or branched is preferred, an alkylene group having 2 to 4 carbon atoms which is linear or branched is more preferred, and an alkylene group having 3 or 4 carbon atoms which is branched is further preferred.

[0071] R B2 and R B3 is preferably methyl.

[0072] n is preferably 4 to 25, more preferably 4 to 10, and further preferably 4 to 8.

[0073] In formula (2), R B1 is preferably a linear or branched alkylene group having 2 to 5 carbon atoms (more preferably a linear or branched alkylene group having 2 to 4 carbon atoms, and further preferably a branched alkylene group having 3 or 4 carbon atoms), R B2 and R B3 is preferably methyl, and n is preferably 4 to 25 (more preferably 4 to 10, and further preferably 3 to 8).

[0074] - Content -

[0075] From the viewpoint of softness and shape stability of the obtained cured product, the content of the compound B is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 8 parts by mass or less, with respect to 100 parts by mass of the compound A. Note that, in the case where the compound A is contained in both the A liquid and the B liquid, the above "with respect to 100 parts by mass of the compound A" refers to the total amount of the compound A contained in the A liquid and the compound A contained in the B liquid. In addition, in the case where the compound B is contained in both the A liquid and the B liquid, the above "content of the compound B" refers to the total amount of the compound B contained in the A liquid and the compound B contained in the B liquid.

[0076] Further, from the viewpoint of storage stability, the content of the compound B is preferably 0.05% by mass to 3% by mass, more preferably 0.1% by mass to 1% by mass, and further preferably 0.1% by mass to 0.5% by mass, with respect to the total mass of the A liquid.

[0077] The A liquid can contain one kind of compound B alone, or can contain two or more kinds of compound B.

[0078] The compound B is preferably a monomer having a molecular weight of less than 1000.

[0079] <<Dispersant>>

[0080] The A liquid contains a dispersant. In the two-liquid curable composition according to the present disclosure, since the A liquid and the B liquid described later each contain a dispersant, the mixability (hereinafter simply referred to as "mixability") of the A liquid and the B liquid is good, and is excellent in suppressing poor curing.

[0081] The dispersing agent contained in the A liquid and the B liquid can be the same dispersing agent or different dispersing agents, but from the viewpoint of storage stability and miscibility, the same dispersing agent is preferred.

[0082] As the dispersing agent, there is no particular limitation, and anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, high-molecular surfactants, alcohols, compounds having a carboxyl group (fatty acids and the like), metal soaps, fatty acid oligomer compounds, fluorine-based surfactants, and boron-based surfactants, and the like can be exemplified.

[0083] Among the above dispersing agents, at least one compound selected from nonionic surfactants, compounds having a carboxyl group, and metal soaps is preferred.

[0084] At least one of the A liquid and the B liquid preferably contains at least one compound selected from nonionic surfactants, compounds having a carboxyl group, and metal soaps as a dispersing agent.

[0085] As the nonionic surfactant, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerol fatty acid ester, polyoxyethylene glycerol fatty acid ester, polyglycerol fatty acid ester, polyglycerol fatty acid ether, polyglycerol monoalkyl ether, sucrose fatty acid ester, polyoxyethylene alkylamine, polyethylene glycol polypropylene glycol block copolymer, acetylene glycol, and polyoxyethylene adducts of acetylene glycol, and the like can be exemplified.

[0086] The compound having a carboxyl group is not particularly limited, and can be a fatty acid having one carboxyl group and a hydrocarbon group in one molecule, or a compound having two or more carboxyl groups in one molecule. As the compound having a carboxyl group, aliphatic carboxylic acids, aromatic carboxylic acids, fatty acids having an aliphatic hydrocarbon group having a carbon atom number of 12 to 22, fatty acids having an unsaturated hydrocarbon group having a carbon atom number of 18 to 22, and the like can be exemplified.

[0087] As the fatty acid having an aliphatic hydrocarbon group having a carbon atom number of 12 to 22, stearic acid, palmitic acid, myristic acid, lauric acid, and the like can be exemplified. As the fatty acid having an unsaturated hydrocarbon group having a carbon atom number of 18 to 22, oleic acid, erucic acid, and the like can be exemplified.

[0088] Further, as the compound having a carboxyl group, multivalent carboxylic acids (i.e., polycarboxylic acids) such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, and adipic acid, which have two or more carboxyl groups in one molecule, alkylamine salts, alkylammonium salts, polycarboxylic acid polyaminoamides, sodium salts of polycarboxylic acids, ammonium salts of polycarboxylic acids, and aminoalcohol salts of polycarboxylic acids, and the like can be exemplified.

[0089] As the polycarboxylic acid compound, there can be mentioned alkylamine salts or alkylammonium salts of polycarboxylic acids, polycarboxylic acid polyaminoamides, sodium salts of polycarboxylic acids, ammonium salts of polycarboxylic acids, and aminoalcohol salts of polycarboxylic acids, and the like.

[0090] As the metal soap, there can be mentioned, for example, metal salts of higher fatty acids such as calcium stearate, potassium oleate, calcium oleate, and the like.

[0091] From the viewpoint of softness of the obtained cured product, as the dispersant, it is preferable to contain at least one compound selected from the group consisting of polyglycerol monoalkyl ether compounds, compounds having a carboxyl group, and metal soaps, more preferable to contain at least one compound selected from the group consisting of polyglycerol monoalkyl ether compounds and fatty acids having an aliphatic hydrocarbon group having a carbon number of 12 to 22, and further preferable to contain at least one compound selected from the group consisting of polyglycerol monoalkyl ether compounds and fatty acids having an unsaturated hydrocarbon group having a carbon number of 18 to 22.

[0092] - Content -

[0093] From the viewpoint of storage stability and miscibility, the content of the dispersant contained in the A liquid is preferably 0.1 to 3% by mass, more preferably 0.2 to 1.5% by mass, and further preferably 0.2 to 0.8% by mass, relative to the total mass of the A liquid.

[0094] From the viewpoint of obtaining a cured product having good softness, shape stability, and inhibitory properties of changes in thermal conductivity, the content of the dispersant contained in the A liquid is preferably 0.5 parts by mass or more and 20 parts by mass or less, and more preferably 1 part by mass or more and 17 parts by mass or less, relative to 100 parts by mass of Compound A (when Compound A is contained in both the A liquid and the B liquid, it refers to the total amount of Compound A contained in the A liquid and Compound A contained in the B liquid).

[0095] The A liquid can contain one dispersant alone, or two or more dispersants.

[0096] < Specific Thiourea Compound >

[0097] The A liquid contains a thiourea compound represented by the following formula (a) (specific thiourea compound). The specific thiourea compound functions as a reducing agent, and promotes the decomposition of the polymerization initiator when the A liquid and the B liquid are mixed, making the polymerization reaction proceed easily.

[0098] [Chemical Formula 4]

[0099]

[0100] In formula (a), R A represents an aliphatic hydrocarbon group having a carbon number of 8 or more and 18 or less, and being linear or branched.B1 , R B2 , and R B3 each independently represents an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms in a straight chain or branched chain, or a hydrogen atom.

[0101] The specific thiourea compound has at least one aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms in a straight chain or branched chain (hereinafter also referred to as "specific hydrocarbon group") in one molecule. Note that, from the viewpoint of exhibiting excellent curability and further suppressing the rate of increase in viscosity after mixing of the A liquid and the B liquid, it is preferable that two or more specific hydrocarbon groups be present in one molecule, and more preferable that R B1 in formula (a) be a specific hydrocarbon group. In this case, R B2 and R B3 may each independently be a specific hydrocarbon group or a hydrogen atom.

[0102] The specific hydrocarbon group has 8 or more and 18 or less carbon atoms. From the viewpoint of exhibiting excellent curability and further suppressing the rate of increase in viscosity after mixing of the A liquid and the B liquid, it is preferable that it have 10 or more and 16 or less carbon atoms, and more preferable that it have 10 or more and 14 or less carbon atoms.

[0103] As the specific thiourea compound, for example, N,N'-dioctylthiourea, N,N'-didecylthiourea, N,N'-dilaurylthiourea, N,N'-ditetradecylthiourea, N,N'-dihexadecylthiourea, N,N'-dioctadecylthiourea, N-octylthiourea, N-decylthiourea, N-laurylthiourea, N-tetradecylthiourea, N-hexadecylthiourea, N-octadecylthiourea, and the like can be given. Among them, from the viewpoint of exhibiting excellent curability and further suppressing the rate of increase in viscosity after mixing of the A liquid and the B liquid, N,N'-dilaurylthiourea is more preferable.

[0104] - Content -

[0105] From the viewpoint of exhibiting excellent curability and further suppressing the rate of increase in viscosity after mixing of the A liquid and the B liquid, the content of the specific thiourea compound is preferably 2.00 parts by mass or more and 20.00 parts by mass or less, more preferably 4.00 parts by mass or more and 17.00 parts by mass or less, and further preferably 6.00 parts by mass or more and 15.00 parts by mass or less, with respect to 100 parts by mass of the compound A (when the compound A is contained in both the A liquid and the B liquid, the total amount of the compound A contained in the A liquid and the compound A contained in the B liquid is meant).

[0106] = Other reducing agents =

[0107] The A liquid can contain other reducing agents in addition to the specific thiourea compound, within a range in which the effects of the present disclosure can be obtained, but from the viewpoint of showing excellent curability and further suppressing the rate of increase in viscosity after mixing of the A liquid and the B liquid, it is preferable that the A liquid contain only the specific thiourea compound. As the other reducing agent, there is no particular limitation as long as it can promote the decomposition of the above-described polymerization initiator, and known reducing agents used in combination with polymerization initiators can be cited. When the two-liquid curable composition according to the present disclosure contains a reducing agent other than the specific thiourea compound, the content of the other reducing agent is preferably 30% by mass or less, more preferably 10% by mass or less, with respect to the total mass of the reducing agent.

[0108] <Thermally conductive filler>

[0109] The A liquid contains a thermally conductive filler.

[0110] The thermally conductive fillers contained in the A liquid and the B liquid described later can be the same thermally conductive filler or can be different thermally conductive fillers, but from the viewpoint of storage stability and miscibility, the thermally conductive fillers contained in the A liquid and the B liquid described later are preferably the same thermally conductive filler.

[0111] The same thermally conductive filler means a filler in which the types and ratios of elements are completely the same.

[0112] As the thermally conductive filler, there is no particular limitation, and known fillers used in TIMs can be used. From the viewpoint of thermal conductivity, as the thermally conductive filler, it is preferable to contain at least one compound selected from the group consisting of zinc oxide and magnesium oxide, and more preferably to contain zinc oxide.

[0113] As the zinc oxide used as the thermally conductive filler, there is no particular limitation, and zinc oxide (ZnO) commonly used as a thermally conductive filler can be cited.

[0114] As the zinc oxide, it is preferable to be in the form of particles, and from the viewpoint of balancing the softness and high conductivity of the obtained cured product, it is more preferable to be particles having a volume average particle diameter of 0.05 μm to 100 μm, and even more preferable to be particles having a volume average particle diameter of 0.1 μm to 50 μm.

[0115] In addition, from the viewpoint of high conductivity, the volume average particle diameter of the zinc oxide is preferably 30 μm or more, and more preferably 30 μm to 50 μm.

[0116] In the case where the A liquid contains zinc oxide, from the viewpoint of highly filling the thermally conductive filler in the composition, it is preferable to contain two or more kinds of zinc oxide having different volume average particle diameters.

[0117] When the A liquid contains two or more kinds of zinc oxide having different volume average particle diameters, the ratio of the largest volume average particle diameter to the smallest volume average particle diameter is preferably 30 to 70 times, more preferably 40 to 60 times, from the viewpoint of high filling of the thermally conductive filler into the composition.

[0118] Note that the smallest volume average particle diameter and the largest volume average particle diameter mean the smallest volume average particle diameter and the largest volume average particle diameter obtained in the volume distribution in the measurement of the volume average particle diameter described later.

[0119] Further, when the A liquid contains zinc oxide, from the viewpoint of high filling of the thermally conductive filler, the zinc oxide contained in the A liquid is more preferably two or more kinds of zinc oxide having a volume average particle diameter of 0.05 μm to 100 μm, different volume average particle diameters, and a difference of 5 μm or more in the volume average particle diameter.

[0120] - Content -

[0121] The content of the thermally conductive filler contained in the A liquid is preferably 50% by mass or more, more preferably 70% by mass to 98% by mass, and further preferably 85% by mass to 98% by mass, relative to the total mass of the A liquid, from the viewpoint of thermal conductivity.

[0122] The content of the thermally conductive filler means the total content of zinc oxide and magnesium oxide, and the compounds other than zinc oxide and magnesium oxide described later.

[0123] The A liquid contained in the two-liquid type curable composition can contain one kind of thermally conductive filler alone, or two or more kinds of thermally conductive fillers.

[0124] When the thermally conductive filler contains zinc oxide, the content of the zinc oxide is preferably 50% by mass or more, more preferably 70% by mass to 100% by mass, and further preferably 85% by mass to 100% by mass, relative to the total mass of the thermally conductive filler contained in the A liquid, from the viewpoint of thermal conductivity.

[0125] The total mass of the thermally conductive filler contained in the A liquid means the total mass of zinc oxide and magnesium oxide contained in the A liquid, and the compounds other than zinc oxide and magnesium oxide described later.

[0126] The A liquid contained in the two-liquid type curable composition can contain one kind of zinc oxide alone, or two or more kinds of zinc oxide.

[0127] The thermally conductive filler contained in the A liquid can contain magnesium oxide.

[0128] The magnesium oxide used as the thermally conductive filler is not particularly limited, and the magnesium oxide (MgO) generally used as a thermally conductive filler can be mentioned.

[0129] The A liquid of the two-liquid curable composition can contain only one magnesium oxide or two or more kinds of magnesium oxides.

[0130] The magnesium oxide is preferably in the form of particles, and from the viewpoint of inhibiting changes in thermal conductivity, the volume average particle diameter is preferably 10 μm or more, more preferably 20 μm to 100 μm, and further preferably 30 μm to 80 μm.

[0131] The thermally conductive filler contained in the A liquid of the two-liquid curable composition according to the present disclosure preferably contains both magnesium oxide and zinc oxide from the viewpoint of shape stability of the obtained cured product.

[0132] The zinc oxide in the case where the thermally conductive filler contains both magnesium oxide and zinc oxide can be exemplified by the above-mentioned zinc oxide, and the preferred modes are the same.

[0133] In the case where the A liquid contains both magnesium oxide and zinc oxide as the thermally conductive filler, the content of the zinc oxide (total content in the case where two or more kinds of zinc oxides are contained) is preferably 50% by mass to 90% by mass, more preferably 60% by mass to 80% by mass, and further preferably 65% by mass to 75% by mass, relative to the total mass of the thermally conductive filler contained in the A liquid, from the viewpoint of obtaining a cured product that is excellent in softness, shape stability, and inhibiting changes in thermal conductivity.

[0134] In the case where the A liquid contains both magnesium oxide and zinc oxide as the thermally conductive filler, the content ratio of the magnesium oxide to the zinc oxide in the thermally conductive filler (magnesium oxide : zinc oxide) is preferably 5 : 1 to 1 : 5, more preferably 1 : 1 to 1 : 4, and further preferably 1 : 1.5 to 1 : 3, on a mass basis, from the viewpoint of obtaining a cured product that is excellent in softness, shape stability, and inhibiting changes in thermal conductivity.

[0135] The above-mentioned volume average particle diameter is calculated from the measured value (volume distribution) measured at a laser wavelength of 405 nm, for example, by a particle size distribution measuring device (for example, SALD-7500nano manufactured by Shimadzu Corporation, product name: Nanoparticle Size Distribution Measuring Device SALD-7500nano).

[0136] In the case where the A liquid contains two or more kinds of zinc oxides having different volume average particle diameters, the content of the zinc oxide having the largest volume average particle diameter calculated from the volume distribution is preferably 50% by mass or more, relative to the total mass of the zinc oxide contained in the thermally conductive filler.

[0137] From the viewpoint of highly filling the thermally conductive filler into the composition, the magnesium oxide and the zinc oxide preferably have two or more peaks in the volume distribution.

[0138] Note that the volume distribution is obtained by the same method as the volume average particle diameter of the above zinc oxide.

[0139] The A liquid contained in the two-liquid curable composition according to the present disclosure can also contain a compound other than the above magnesium oxide and zinc oxide as a thermally conductive filler.

[0140] As the compound other than zinc oxide, aluminum oxide, aluminum hydroxide, aluminum nitride, boron nitride, carbon, and the like can be given.

[0141] << Rheology control agent >>

[0142] The A liquid preferably further contains a rheology control agent from the viewpoint of mixability and storage stability.

[0143] The rheology control agent herein refers to an additive that imparts non-Newtonian behavior to a material when the shear rate is changed. Specifically, the rheology control agent is an additive that imparts flow properties such that the shear viscosity becomes high in a low shear rate region and the shear viscosity becomes low in a high shear rate region.

[0144] The rheology control agent can be an inorganic compound-based rheology control agent or an organic compound-based rheology control agent. As the inorganic compound-based rheology control agent, fumed silica, bentonite, mica, and kaolin, and the like can be given.

[0145] Further, as the organic compound-based rheology control agent, urea-modified polymers, polyurethane-modified polymers, castor oil wax, polyethylene wax, polyamide wax, and fatty acid amide wax, and the like can be given.

[0146] Among them, as the rheology control agent, an inorganic compound-based rheology control agent is preferred, fumed silica or bentonite is more preferred, and bentonite is further preferred. In the case of using fumed silica, a substance that makes the surface hydrophobic by a silane coupling agent or other surface modifier is preferred. Further, in the case of using bentonite, an organically modified bentonite that is organically modified by a quaternary ammonium salt or other organic modifier is preferred.

[0147] The content of the rheology control agent is not particularly limited and can be appropriately set.

[0148] From the viewpoint of storage stability, the A liquid preferably does not contain a polymerization initiator. Not containing a polymerization initiator means that the content is 0 mass% or the amount contained does not show polymerization initiating ability.

[0149] << Polymerizable polymer >>

[0150] From the viewpoint of storage stability, the A liquid can also contain, as necessary, a polymerizable polymer (hereinafter also referred to as "compound C"). The polymerizable polymer in the present disclosure refers to a polymerizable polymer having one or more (meth)acrylate groups in one molecule, and having a weight average molecular weight (Mw) of 1000 or more. In the present disclosure, the concept of "polymer" also includes so-called oligomers.

[0151] The main chain of the polymerizable polymer (compound C) is not particularly limited, but from the viewpoint of compatibility with other compounds, a polymer of a (meth)acryl monomer, or a polymer of a butadiene monomer is preferred, and a polymer of a (meth)acryl monomer is more preferred.

[0152] As the compound C, for example, the trade name "KANEKA XMAP RC110C" (manufactured by KANEKA Co., Ltd., acrylic polymer having acrylate groups at both terminals), the trade name "KANEKA XMAP MM110C" (manufactured by KANEKA Co., Ltd., acrylic polymer having acrylate groups at one terminal), "NISSO PB TEAI-1000" (manufactured by Nippon Soda Co., Ltd., hydrogenated butadiene polymer having acrylate groups at both terminals), and the like can be exemplified.

[0153] When the A liquid contains the compound C, as the content of the compound C, relative to the total mass of the A liquid, 10% by mass or less is preferred, 7% by mass or less is more preferred, and 5% by mass or less is further preferred.

[0154] From the viewpoint of storage stability, the A liquid can also contain, as necessary, a plasticizer described later. As the plasticizer contained in the A liquid, the same meaning as the plasticizer in the B liquid described later, and the same preferred modes are preferred.

[0155] When the A liquid contains the plasticizer, as the content of the plasticizer, relative to the total mass of the A liquid, 5% by mass or less is preferred, and 3% by mass or less is more preferred.

[0156] The lower limit value is not particularly limited, but 0% by mass or more is preferred.

[0157]

[0158] The two-liquid type curable composition according to the present disclosure contains an A liquid and a B liquid, and the B liquid contains a polymerization initiator, a dispersant, a plasticizer, and a thermally conductive filler.

[0159] < <Polymerization initiator> >

[0160] The B liquid contains a polymerization initiator.

[0161] As the polymerization initiator, a compound which generates a polymerization initiator species such as a radical, a cation, or the like by light, heat, or energy of both can be appropriately selected from known thermal polymerization initiators, known photopolymerization initiators, and the like.

[0162] As the polymerization initiator, from the viewpoint of reactivity with the compound A and the compound B, a radical polymerization initiator is preferred, a peroxide which generates a free radical by heat is more preferred, and an organic peroxide which generates a free radical by heat is further preferred.

[0163] As the organic peroxide, isobutyl peroxide, α,α'-bis(neodecanoylperoxy)diisopropylbenzene, cumyl isopropyl peroxynonanoate, di-n-propyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-tert-butylcyclohexyl) peroxydicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, di-2-ethoxyethyl peroxydicarbonate, di(ethylhexyl) peroxydicarbonate, tert-hexyl peroxyneodecanoate, dimethoxybutyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, peroxyoctanoic acid, peroxylauric acid, peroxystearic acid, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, peroxysuccinic acid, 2,5-dimethyl-2,5-di(2-ethylhexanoyl)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, tert-hexyl peroxy-2-ethylhexanoate, 4-methylperoxybenzoyl, tert-butyl peroxy-2-ethylhexanoate, m-toluoyl peroxybenzoyl, peroxybenzoyl, tert-butyl peroxyisobutyrate, 1,1-bis(tert-butyl peroxy) 2-methylcyclohexane, 1,1-bis(tert-hexyl peroxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-hexyl peroxy)cyclohexane, 1,1-bis(tert-butyl peroxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butyl peroxy)cyclohexanone, 2,2-bis(4,4-dibutyl peroxy cyclohexyl)propane, 1,1-bis(tert-butyl peroxy)cyclododecane, tert-hexyl peroxyisopropyl monocarbonate, tert-butyl peroxy maleic acid, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxy laurate, 2,5-dimethyl-2,5-di(m-toluoyl peroxy)hexane, tert-butyl peroxyisopropyl monocarbonate, tert-butyl peroxy-2-ethylhexyl carbonate, tert-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoyl peroxy)hexane, tert-butyl peroxyacetate, 2,2-bis(tert-butyl peroxy)butane, tert-butyl peroxybenzoate, n-butyl-4,4-bis(tert-butyl peroxy)valerate, di-tert-butyl peroxy isophthalate, α,α'-bis(tert-butyl peroxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane, tert-butyl peroxy cumene, di-tert-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexyne, diisopropylbenzene hydroperoxide, tert-butyl trimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, and lauryl peroxide.

[0164] Among them, from the viewpoint of reactivity, as the organic peroxide, at least one compound selected from the group consisting of benzoyl peroxide, t-butyl peroxy-2-ethylhexyl carbonate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexyl carbonate, and cumene hydroperoxide is preferable.

[0165] - Content -

[0166] From the viewpoint of obtaining a cured product having good softness, shape stability, and inhibitory properties of changes in thermal conductivity, the content of the polymerization initiator is preferably 0.5 parts by mass or more and 50 parts by mass or less, more preferably 0.5 parts by mass or more and 30 parts by mass or less, and further preferably 1 part by mass or more and 15 parts by mass or less, with respect to 100 parts by mass of the compound A (when the compound A is contained in both the A liquid and the B liquid, the total amount of the compound A contained in the A liquid and the compound A contained in the B liquid is meant).

[0167] From the viewpoint of storage stability, the content of the polymerization initiator in the B liquid is preferably 0.05% by mass or more and 3% by mass or less, more preferably 0.1% by mass or more and 2% by mass or less, and further preferably 0.2% by mass or more and 1% by mass or less, with respect to the total mass of the B liquid.

[0168] The B liquid can contain one kind of polymerization initiator alone, or two or more kinds of polymerization initiators.

[0169] <<Dispersant>>

[0170] The B liquid contains a dispersant. The dispersant contained in the B liquid has the same meaning as the dispersant contained in the above-mentioned A liquid, and the preferable modes other than the content of the dispersant are the same.

[0171] The dispersant contained in the B liquid can be the same as or different from the dispersant contained in the A liquid. From the viewpoint of storage stability, the dispersant contained in the B liquid is preferably the same as the dispersant contained in the A liquid.

[0172] From the viewpoints of storage stability and miscibility, the content of the dispersant in the B liquid is preferably 0.05% by mass or more and 3% by mass or less, more preferably 0.1% by mass or more and 2% by mass or less, and further preferably 0.1% by mass or more and 1% by mass or less, with respect to the total mass of the B liquid.

[0173] <<Plasticizer>>

[0174] The B liquid contains a plasticizer. As the plasticizer, there is no particular limitation, and, for example, in addition to a polymer, a fatty acid ester compound having an unsaturated hydrocarbon group, and an aromatic carboxylic acid ester compound, which are used as plasticizers, an oil containing a fatty acid having an unsaturated hydrocarbon group and an aromatic carboxylic acid, and the like can be exemplified.

[0175] In the present disclosure, "polymer" means a compound having a weight average molecular weight (Mw) of 1000 or more.

[0176] In the present disclosure, the concept of "polymer" also includes so-called oligomers.

[0177] As the polymer, for example, an acrylic polymer, a polyester polymer, a polyurethane polymer, a silicone polymer, and the like can be exemplified, but from the viewpoint of heat resistance and softness of the obtained cured product, an acrylic polymer is preferred.

[0178] When the plasticizer is a polymer, from the viewpoint of heat resistance and softness of the obtained cured product, a polymer having a glass transition temperature of -20°C or lower is preferred, and an acrylic polymer having a glass transition temperature of -20°C or lower is more preferred.

[0179] The glass transition temperature (Tg) of the polymer is obtained by investigating the inflection point of the DSC curve measured using a differential thermal analysis device (DSC, Differential Scanning Calorimeter).

[0180] As the fatty acid ester compound having an unsaturated hydrocarbon group, for example, ester compounds such as palmitoleic acid, oleic acid, linoleic acid, and linolenic acid can be exemplified.

[0181] As the aromatic carboxylic acid ester compound, ester compounds such as phthalic acid, terephthalic acid, benzoic acid, and trimellitic acid can be exemplified.

[0182] From the viewpoint of high-temperature stability, the plasticizer preferably contains an aromatic carboxylic acid ester compound, and preferably contains a trimellitate ester.

[0183] -Content-

[0184] From the viewpoint of balancing the miscibility, heat resistance, and softness, the content of the plasticizer (the total amount when two or more plasticizers are contained) is preferably 3% by mass or more and 15% by mass or less, and more preferably 5% by mass or more and 12% by mass or less, relative to the total mass of the B liquid.

[0185] The B liquid contained in the two-liquid type curable composition can contain one plasticizer alone, or two or more plasticizers.

[0186] <Thermally conductive filler>

[0187] The B liquid contains a thermally conductive filler. The thermally conductive filler contained in the B liquid has the same meaning as the thermally conductive filler contained in the A liquid, and the preferred modes are also the same.

[0188] The thermally conductive filler contained in the B liquid can be the same as the thermally conductive filler contained in the A liquid, or can be different from the thermally conductive filler contained in the A liquid, but from the viewpoint of storage stability and miscibility, it is preferable to be the same as the thermally conductive filler contained in the A liquid.

[0189] From the viewpoint of thermal conductivity, the content of the thermally conductive filler contained in the B liquid is preferably 50% by mass or more, more preferably 70% by mass to 98% by mass, and further preferably 85% by mass to 98% by mass, with respect to the total mass of the B liquid.

[0190] < Compound having polymerizability >>

[0191] From the viewpoint of miscibility of the A liquid and the B liquid, the B liquid can contain a compound having polymerizability. As the compound having polymerizability, a compound having one (meth)acrylate group in one molecule (i.e., the above-mentioned compound A), a compound having two or more (meth)acrylate groups in one molecule (i.e., the above-mentioned compound B), and a polymerizable polymer (i.e., the above-mentioned compound C) can be exemplified.

[0192] The B liquid can contain only one compound having polymerizability, or can contain two or more compounds having polymerizability. That is, it can contain only one of the compound A, the compound B, and the compound C, or can contain two or more of the compound A, the compound B, and the compound C. However, when the B liquid contains a compound having polymerizability, from the viewpoint of storage stability, it is preferable to contain only the compound A.

[0193] • Compound having one (meth)acrylate group in one molecule (compound A)

[0194] When the B liquid contains the compound A, as the compound A contained in the B liquid, the meaning is the same as the compound A contained in the above-mentioned A liquid, and the preferred modes other than the content of the compound A are also the same.

[0195] The compound A contained in the B liquid can be the same as the compound A contained in the A liquid, or can be different. From the viewpoint of storage stability, the compound A contained in the B liquid is preferably the same as the compound A contained in the A liquid.

[0196] From the viewpoint of storage stability, the content of the compound A in the B liquid is preferably 1% by mass to 12% by mass, and more preferably 2% by mass to 10% by mass, with respect to the total mass of the B liquid. The B liquid can contain only one compound A, or can contain two or more compounds A.

[0197] • a compound having two or more (meth)acrylate groups in one molecule (Compound B)

[0198] When the B liquid contains Compound B, as Compound B contained in the B liquid, the preferred modes other than the content of Compound B are the same as those of Compound B contained in the above-mentioned A liquid.

[0199] Compound B contained in the B liquid can be the same as or different from Compound B contained in the A liquid. From the viewpoint of storage stability, Compound B contained in the B liquid is preferably the same as Compound B contained in the A liquid.

[0200] From the viewpoint of softness and shape stability of the obtained cured product, the content of Compound B is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 8 parts by mass or less, with respect to 100 parts by mass of Compound A. Note that, when Compound A is contained in both the A liquid and the B liquid, the above-mentioned "with respect to 100 parts by mass of Compound A" refers to the total amount of Compound A contained in the A liquid and Compound A contained in the B liquid. In addition, when Compound B is contained in both the A liquid and the B liquid, the above-mentioned "content of Compound B" refers to the total amount of Compound B contained in the A liquid and Compound B contained in the B liquid.

[0201] Furthermore, from the viewpoint of storage stability, the content of Compound B in the B liquid is preferably 0.05% by mass or more and 3% by mass or less, more preferably 0.1% by mass or more and 1% by mass or less, and further preferably 0.1% by mass or more and 0.5% by mass or less, with respect to the total mass of the B liquid.

[0202] The B liquid can contain one kind of Compound B alone or two or more kinds of Compound B.

[0203] • a polymerizable polymer (Compound C)

[0204] When the B liquid contains Compound C, as Compound C contained in the B liquid, the preferred modes other than the content of Compound C are the same as those of Compound C contained in the above-mentioned A liquid.

[0205] When Compound C is contained in both the A liquid and the B liquid, Compound C contained in the B liquid can be the same as or different from Compound C contained in the A liquid. From the viewpoint of storage stability, Compound C contained in the B liquid is preferably the same as Compound C contained in the A liquid.

[0206] When the B liquid contains Compound C, as the content of Compound C, it is preferably 10% by mass or less, more preferably 7% by mass or less, and further preferably 5% by mass or less, with respect to the total mass of the B liquid.

[0207] << Rheology Control Agent >>

[0208] From the viewpoint of the mixing property and the storage stability, the B liquid preferably further contains a rheology control agent.

[0209] As the rheology control agent, the same meaning as that in the A liquid and the same preferred mode are preferable.

[0210] From the viewpoint of the storage stability, the B liquid can not contain the above-mentioned compound A, compound B, and compound C. On the other hand, from the viewpoint of the mixing property of the A liquid and the B liquid, the B liquid can contain at least one selected from the above-mentioned compound A, compound B, and compound C. The B liquid not containing the compound A, compound B, and compound C means that the content of the compound A, compound B, and compound C in the B liquid is 0 mass% or the content does not show a polymerization reaction.

[0211] From the viewpoint of the storage stability, the B liquid preferably does not contain a reducing agent. The B liquid not containing the reducing agent means that the content of the reducing agent is 0 mass% or the content does not show a reducing ability.

[0212] <Other matters related to the two-liquid curable composition>

[0213] <<Other additives>>

[0214] The two-liquid curable composition according to the present disclosure can further contain, as needed, components other than the compound A, compound B, compound C, polymerization initiator, dispersing agent, thermally conductive filler, plasticizer, reducing agent (including the above-mentioned specific thiourea compound), and rheology control agent (hereinafter also referred to as "other additives") in the A liquid and / or B liquid.

[0215] As the other additives, additives such as anticorrosive agents, rust-preventive agents, and the like can be appropriately incorporated.

[0216] The above-mentioned additives can be used alone or in combination of two or more.

[0217] As the anticorrosive agent, benzotriazole, tolyltriazole, thiadiazole, benzimidazole, and the like can be exemplified.

[0218] As the rust-preventive agent, sulfonic acid metal salt-based compounds, sorbitan compounds, and the like can be exemplified.

[0219] <Mass ratio of the A liquid to the B liquid>

[0220] From the viewpoint of the mixing property and the usability, the mass ratio of the A liquid to the B liquid is preferably 4: 1 to 1: 4, more preferably 2: 1 to 1: 2, and most preferably 1: 1 on a mass basis.

[0221] <<Shear viscosity of the A liquid and the B liquid>>

[0222] The shear viscosities of the A liquid and the B liquid are each independently preferably 100 Pa-s to 400 Pa-s, more preferably 100 Pa-s to 300 Pa-s, and further preferably 100 Pa-s to 200 Pa-s, from the viewpoints of mixability and coating properties.

[0223] The above-mentioned shear viscosities are values measured using a viscoelasticity measuring device (for example, product name: MCR301, manufactured by Anton Paar) under conditions where the measurement temperature is 25°C, the shear rate is 10 s -1

[0224] (Method for producing two-liquid type curable composition)

[0225] The method for producing the two-liquid type curable composition according to the present disclosure is not particularly limited, and can be produced, for example, by the following method.

[0226] The A liquid contained in the two-liquid type curable composition according to the present disclosure is obtained by stirring and mixing, for example, the compound A, the compound B, the dispersant, the reducing agent containing the thiourea compound represented by the above-mentioned formula (a) (specific thiourea compound), and the thermally conductive filler, and the compound C, the plasticizer, the rheology control agent, and other additives, which are added as necessary, by putting them into a stirring container.

[0227] Further, the B liquid contained in the two-liquid type curable composition according to the present disclosure is obtained by stirring and mixing, for example, the polymerization initiator, the dispersant, the plasticizer, and the thermally conductive filler, and the compound A, the compound B, the compound C, the rheology control agent, and other additives, which are added as necessary, by putting them into a stirring container.

[0228] Note that the stirring and mixing can use a known stirrer or the like.

[0229] In the method for producing the two-liquid type curable composition according to the present disclosure, when the rheology control agent and other additives are added, the stirring can be performed for a time until the rheology control agent and the additives are dissolved or dispersed.

[0230] Further, the order of addition of the rheology control agent and other additives is not particularly limited, and can be appropriately set. For example, the compound A, the compound B, the dispersant, and the reducing agent containing the specific thiourea compound, or the polymerization initiator, the dispersant, and the plasticizer can be added together with the rheology control agent and other additives to the stirring container, or the "compound A, compound B, dispersant, reducing agent" or "polymerization initiator, dispersant, plasticizer" can be mixed, and then the rheology control agent and other additives can be added.

[0231] (Cured product) ​

[0232] The cured product according to the present disclosure is a cured product of the two-liquid curable composition according to the present disclosure. As a method of curing the two-liquid curable composition, there is no particular limitation as long as the A liquid and the B liquid contained in the two-liquid curable composition according to the present disclosure are mixed.

[0233] As a method of mixing the A liquid and the B liquid, there is no particular limitation, and a publicly known stirrer or the like can be used.

[0234] From the viewpoints of mixability and usability, the mixing ratio of the A liquid to the B liquid is preferably 4: 1 to 1: 4, more preferably 2: 1 to 1: 2, and most preferably 1: 1, on a mass basis.

[0235] As the temperature at the time of mixing the A liquid and the B liquid (i.e., the curing temperature), there is no particular limitation, and it can be room temperature (25°C) or 10°C to 40°C.

[0236] In addition, irradiation with active energy rays, heating, or the like can be further performed after the A liquid and the B liquid contained in the two-liquid curable composition according to the present disclosure are mixed.

[0237] As the heating temperature at the time of heating, it is preferably 60°C or higher, and more preferably 70°C or higher. In addition, as the heating temperature time, it is preferably 1 minute to 120 minutes.

[0238] From the viewpoints of softness, shape stability, and inhibition of changes in thermal conductivity, the thermal conductivity of the cured product according to the present disclosure is preferably 0.5 [W / (m·K)] to 50 [W / (m·K)], and more preferably 1 [W / (m·K)] to 20 [W / (m·K)].

[0239] From the viewpoint of stress relaxation to the surrounding components of the cured product, the softness of the cured product according to the present disclosure is preferably an Asker C hardness of 70 or less, and more preferably 66 or less.

[0240] Similarly, the Shore OO hardness is preferably 90 or less, and more preferably 86 or less.

[0241] In the present disclosure, the Asker C hardness is measured in accordance with JIS K7312: 1996, and the Shore OO hardness is measured in accordance with ASTM D2240.

[0242] <Usage>

[0243] The two-liquid curable composition according to the present disclosure can be suitably used, for example, as a TIM filled in a recess (gap between a heat generating body and a heat sink) formed on a substrate.

[0244] The two-liquid curable composition according to the present disclosure exhibits excellent curability, and further suppresses the rate of increase in viscosity after mixing of the A liquid and the B liquid, and thus can be suitably used as a gap filler.

[0245] Examples

[0246] Hereinafter, the two-liquid curable composition according to the present disclosure will be specifically described by way of examples. Note that the two-liquid curable composition according to the present disclosure is not limited by any of these examples.

[0247] (Examples 1 to 3 and Comparative Examples 1 to 4)

[0248] Each raw material was mixed in the amounts (parts by mass) described in Tables 1 and 2 using a self-rotation · revolution agitator (THINKY Corporation, product name: awatoritentaro ARV-310) at 2000 rpm, 2 minutes, and atmospheric pressure to prepare a two-liquid curable composition composed of an A liquid and a B liquid.

[0249] The two-liquid curable compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were used to perform the following evaluations. The results are described in Tables 1 and 2.

[0250] -Evaluation-

[0251] <Shear Viscosity>

[0252] The shear viscosity was measured using a viscoelasticity measuring device (product name: MCR301, Anton Paar Corporation) under conditions in which the measurement temperature was 25°C and the shear rate was 10 s -1 The smaller the difference in shear viscosity between the A liquid and the B liquid, the more excellent the mixability.

[0253] <Pot Life>

[0254] The time taken for the viscosity to reach twice the value after mixing the A liquid and the B liquid at the mixing ratio (mass ratio) described in Tables 1 and 2 was measured.

[0255] <Thermal Conductivity>

[0256] The thermal conductivity was measured in accordance with ASTM D5470.

[0257] After mixing A liquid and B liquid at the mixing ratio (mass ratio) described in Tables 1 and 2, the upper and lower of the two-liquid type curable composition molded into 10 mm x 10 mm x 1 mm were sandwiched with a 10 mm x 10 mm copper plate, and left to stand for 24 hours in an environment of 25°C (only Comparative Example 4 was left to stand for 96 hours), to cure it. Then, the thermal resistance (unit: K cm / W) was measured with a thermal resistance measuring device (manufactured by Tsukuba Rika Seiki (K.K.), product name: Thermal Resistance Measuring Device), and converted into the thermal conductivity (unit: W / m K). 2 / W), and converted into the thermal conductivity (unit: W / m K).

[0258] <Shape stability>

[0259] - Shore OO hardness (sample thickness: 6 mm) -

[0260] The Shore OO hardness of the cured product of the two-liquid type curable composition was measured in accordance with ASTM D2240.

[0261] After mixing A liquid and B liquid at the mixing ratio described in Tables 1 and 2, the curable composition was molded into 30 mm x 15 mm x 6 mm (thickness 6 mm), and cured under the same curing conditions as the evaluation test of the thermal conductivity. The obtained cured product was subjected to measurement of the Shore OO hardness using a durometer (hardness gauge) (product name: GS-754G, manufactured by TECLOCK (K.K.)).

[0262] The smaller the value of the Shore hardness, the more easily the external force is mitigated, and thus the shape is easily stably maintained.

[0263] - Asker C hardness (sample thickness: 6 mm) -

[0264] The Asker C hardness of the cured product of the curable composition was measured in accordance with JIS K7312: 1996.

[0265] After mixing A liquid and B liquid at the mixing ratio described in Tables 1 and 2, the curable composition was molded into 30 mm x 15 mm x 6 mm (thickness 6 mm), and cured under the same curing conditions as the evaluation test of the thermal conductivity. The obtained cured product was subjected to measurement of the ASKER C hardness using an ASKER rubber hardness tester C type (manufactured by Polymer Instrument Co., Ltd.).

[0266] The smaller the value of the Asker C hardness, the more easily the external force is mitigated, and thus the shape is easily stably maintained.

[0267] [Table 1]

[0268]

[0269] [Table 2]

[0270]

[0271] Details of each component described in Table 1 and Table 2 are shown below. "-" in Table 1 and Table 2 indicates that the corresponding component is not contained or the corresponding evaluation is not performed.

[0272] << Compound a >>

[0273] • LIGHT ESTER L: lauryl methacrylate (compound represented by formula (1)); manufactured by Kyoeisha Chemical Co., Ltd.

[0274] • NK Ester ITEC: 2-decyltetradecyl methacrylate (compound represented by formula (1)), manufactured by Shin Nakamura Chemical Co., Ltd.

[0275] << Compound c >>

[0276] • NK Ester 9PG: polypropylene glycol dimethacrylate (9PG) (compound represented by formula (2)), manufactured by Shin Nakamura Chemical Co., Ltd.

[0277] << Compound d >>

[0278] • KANEKA XMAP RC110C: difunctional acryloyl-terminated polyacrylate, manufactured by Kaneka Corporation

[0279] • 9-octadecenoic acid (oleic acid); manufactured by NOF Corporation

[0280] • Cobalt hexoate: manufactured by Toyo Rika Corporation, Co: 12%

[0281] • Trimethylthiourea: manufactured by Sanso Chemical Industry Co., Ltd.

[0282] • N,N'-dibutylthiourea (C4): manufactured by Sanso Chemical Industry Co., Ltd.

[0283] • N,N'-diphenylthiourea: manufactured by Tokyo Chemical Industry Co., Ltd.

[0284] • N,N'-dilaurylthiourea (C12): manufactured by Kawaguchi Chemical Industry Co., Ltd.

[0285] • TRIGONOX K-80: cumyl hydroperoxide, manufactured by NOURYON Corporation

[0286] • ADEKA CIZER (アデカサイザー) C-880: Trimellitic acid mixed linear alkyl ester, manufactured by ADEKA Corporation

[0287] • KAOLUBE (カオールーブ) 262: manufactured by Kao Corporation << Rheology control agent >>

[0288] • CLAYTONE-40: manufactured by BYK << Thermal conductive filler >>

[0289] • Zinc oxide (ZnO)

[0290] • Calcined zinc oxide; volume average particle diameter D50; 10 pm, manufactured by HAKUSUI TECH, Inc. • Zinc oxide 1 kind; volume average particle diameter D50; 0.6 pm, manufactured by Sakai Chemical Industry Co., Ltd.

[0291] • Magnesium oxide: volume average particle diameter D50; 60 pm, manufactured by Denka Corporation, spherical magnesium oxide DMG-60

[0292] As shown in Tables 1 and 2, it was found that the two-liquid curable compositions of Examples 1 to 2 had excellent curability, and the viscosity increase rate after mixing of the A liquid and the B liquid was suppressed, as compared with the two-liquid curable compositions of Comparative Examples 1 to 4. In addition, it was found that the two-liquid curable composition of Example 3, which contained a compound having one (meth)acrylate group in one molecule in the B liquid, had excellent curability, and the viscosity increase rate after mixing of the A liquid and the B liquid was suppressed, as compared with the two-liquid curable compositions of Comparative Examples 1 to 4. Note that in Comparative Example 3 in which N,N'-diphenylthiourea was used as a reducing agent, the A liquid and the B liquid did not mix, and a cured product could not be formed, and thus evaluation of the thermal conductivity and the shape stability could not be performed. In Comparative Example 4 in which cobalt hexanate was used as a reducing agent, the pot life was excessively long, and it was found that a long time was required to cure after mixing of the A liquid and the B liquid, which was a result of poor curability.

[0293] Note that the disclosure of Japanese Application No. 2023-044693 is incorporated herein by reference in its entirety.

[0294] All of the documents, patent applications and technical standards described herein are incorporated by reference to the extent that the incorporated reference is in its entirety specifically and individually incorporated by reference.

Claims

1. A two-liquid type curable composition comprising: A liquid containing a compound having one (meth)acrylate group in one molecule, a compound having two or more (meth)acrylate groups in one molecule, a dispersant, a thiourea compound represented by the following formula (a), and a thermally conductive filler; and B liquid containing a polymerization initiator, a dispersant, a plasticizer, and a thermally conductive filler, [Chemical Formula 1] In formula (a), R A represents an aliphatic hydrocarbon group having 8 to 18 carbon atoms which is linear or branched, R B1 , R B2 , and R B3 each independently represents an aliphatic hydrocarbon group having 8 to 18 carbon atoms which is linear or branched, or a hydrogen atom.

2. The two-liquid type curable composition according to claim 1, wherein In the thiourea compound represented by the formula (a), R B1 is an aliphatic hydrocarbon group having 8 or more and 18 or less carbon atoms and being linear or branched.

3. The two-liquid type curable composition according to claim 1, wherein The content of the thiourea compound represented by the formula (a) is 2.00 parts by mass or more and 20.00 parts by mass or less, relative to 100 parts by mass of the compound having one (meth)acrylate group in one molecule.

4. The two-liquid type curable composition according to claim 1, wherein The B liquid contains a compound having one (meth)acrylate group in one molecule.

5. A cured product of the two-liquid type curable composition according to any one of claims 1 to 4.

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