Hardening components and hardening agents

Abstract

To provide a curable composition and a cured product that yields a cured product with excellent adhesion and flexibility. [Solution] A curable composition and a cured product thereof, comprising a thermally conductive filler, monomer M1, monomer M2, polymerization initiator, and dispersant, wherein monomer M1 comprises a monomer represented by the following formula 1 or a monomer consisting of a (meth)acryloyl group and a residue having a heterocyclic structure, and monomer M2 comprises a monomer consisting of a (meth)acryloyl group and a residue not having a heterocyclic structure (however, monomer M2 does not contain the monomer represented by the following formula 1).

Description

[Technical Field]

[0001] This disclosure relates to curable compositions and cured products. [Background technology]

[0002] In recent years, the performance of electronic devices such as personal computers, mobile phones, and personal digital assistants (PDAs), as well as lighting and display devices such as light-emitting diodes (LEDs) and electronic luminescents (ELs), has improved dramatically, largely due to significant improvements in the performance of computing elements and light-emitting elements. However, this improvement in performance has also led to a significant increase in heat generation, making heat dissipation in electronic devices, lighting, and display devices a critical issue. As a thermal countermeasure, a TIM (Thermal Interface Material) is used between the heat-generating element and the heat-sink to transfer the heat generated by the computing element or light-emitting element to the heat sink without loss, and to dissipate the heat through the heat sink. Commonly used TIMs include heat dissipation sheets, thermal conductive grease, and gap fillers. Gap fillers, which are initially paste-like and harden into a solid after application, are attracting particular attention.

[0003] As a composition applicable as TIM, for example, Patent Document 1 discloses a thermally conductive silicone rubber composition containing (A) an organopolysiloxane having a viscosity of 50 to 100,000 mPa·s at 25°C and containing an average of 2 or more silicon atom-bonded alkenyl groups per molecule, (B) an organopolysiloxane having a viscosity of 1 to 100,000 mPa·s at 25°C and containing an average of 2 or more silicon atom-bonded hydrogen atoms per molecule, (C) a thermally conductive filler, (D) a platinum catalyst, and (E) a specific amount of an organopolysiloxane having a predetermined structure and a molecular weight of 10,000 or more.

[0004] Furthermore, Patent Document 2 discloses a curable composition comprising 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 or magnesium oxide. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-325211 [Patent Document 2] International Publication No. 2020 / 149193 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] TIMs (Thermal Insulation Materials) are sometimes required to possess both thermal conductivity and adhesive properties, that is, to be heat-dissipating adhesives. Heat-dissipating adhesives are expected to be used in environments with more drastic temperature changes than conventional adhesives. However, commonly used adhesive materials such as acrylic resins and epoxy resins form a very hard skeleton after the curing reaction, resulting in a cured product with low flexibility. As a result, the cured product cannot keep up with thermal expansion and contraction and is susceptible to thermal changes. From this perspective, there is currently a demand for curable compositions that achieve both adhesion and flexibility.

[0007] One embodiment of the present disclosure, in view of the above circumstances, aims to provide a curable composition that yields a cured product with excellent adhesion and flexibility, and a cured product with excellent adhesion and flexibility. [Means for solving the problem]

[0008] This disclosure includes the following aspects: <1> Comprising a thermally conductive filler, a monomer M1, a monomer M2, a polymerization initiator, and a dispersant, the monomer M1 includes a monomer represented by the following formula 1, the monomer M2 includes a monomer consisting of a (meth)acryloyl group and a residue having no heterocyclic structure (provided that the monomer M2 does not include a monomer represented by the following formula 1), a curable composition.

Chemical Formula

[0009] <2> Comprising a thermally conductive filler, a monomer M1, a monomer M2, a polymerization initiator, and a dispersant, the monomer M1 includes a monomer consisting of a (meth)acryloyl group and a residue having a heterocyclic structure, the monomer M2 includes a monomer consisting of a (meth)acryloyl group and a residue having no heterocyclic structure (provided that the monomer M2 does not include a monomer represented by the following formula 1), a curable composition.

Chemical Formula

[0010] <3> In formula 1, R1 represents a group represented by the following formula 2, and R2 to R 10 all represent hydrogen atoms, the curable composition according to <1>.

Chemical Formula

[0011] <4> The content of monomer M1 is between 5% by mass and 35% by mass, based on the total content of monomer M1 and monomer M2. <1> ~ <3> A curable composition as described in any one of the following. <5> The content of monomer M1 is 10% by mass or more and 30% by mass or less, based on the total content of monomer M1 and monomer M2. <1> ~ <4> A curable composition as described in any one of the following. <6> In monomer M2, residues that do not have a heterocyclic structure are organic groups with a total of 12 or more carbon atoms. <1> ~ <5> A curable composition as described in any one of the following. <7> The thermally conductive filler contains zinc oxide. <1> ~ <6> A curable composition as described in any one of the following. <8> <1> ~ <7> A cured product of any one of the curable compositions described in any one of the above. [Effects of the Invention]

[0012] According to one embodiment of the present disclosure, a curable composition can be provided that yields a cured product with excellent adhesion and flexibility, and a cured product with excellent adhesion and flexibility can be provided. [Modes for carrying out the invention]

[0013] The curable compositions and cured products related to this disclosure will be described in detail below.

[0014] In this disclosure, the "~" symbol used to indicate a numerical range represents a range that includes the numerical values ​​specified as its upper and lower limits, respectively. Furthermore, if only the upper limit of a numerical range represented by "~" has a unit specified, it means that the lower limit also has the same unit. In this disclosure, if there are multiple substances corresponding to each component in a composition, the content or amount of each component in the composition means the total content or amount of those multiple substances present in the composition, unless otherwise specified. In numerical ranges described in stages within this disclosure, an upper or lower limit stated in one numerical range may be replaced with an upper or lower limit in another numerical range described in stages. Within the numerical ranges described in this disclosure, any upper or lower limit specified within a numerical range may be replaced with the values ​​shown in the examples.

[0015] In this disclosure, "(meth)acrylic" is a term used to encompass both acrylic and methacrylic, and "(meth)acryloyl" is a term used to encompass both acryloyl and methacryloyl. In this disclosure, if multiple instances of a particular component are present in the composition, unless otherwise specified, each component in the composition refers to the total amount of the relevant substance present in the composition. In this disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.

[0016] In this disclosure, "JIS" is used as an abbreviation for Japanese Industrial Standards. In this disclosure, "ASTM" refers to the international standards developed by ASTM International. In this disclosure, ordinal numbers (e.g., "1st" and "2nd") are terms used to distinguish between multiple components and do not limit the number of components or their relative importance.

[0017] In this disclosure, "monomer" means a polymerizable compound having a molecular weight of less than 1,000. In this disclosure, "polymer" means a compound having a weight-average molecular weight (Mw) of 1,000 or more. In this disclosure, the concept of "polymer" also includes so-called oligomers.

[0018] (Curable composition) The curable compositions relating to this disclosure include the first and second embodiments. In the following description, matters that are not explicitly stated as belonging to the first or second embodiment are common to both the first and second embodiments.

[0019] A first aspect of the curable composition relating to this disclosure is: It contains a thermally conductive filler, monomer M1, monomer M2, polymerization initiator, and dispersant. Monomer M1 contains a monomer represented by the following formula 1, Monomer M2 includes monomers consisting of a (meth)acryloyl group and residues that do not have a heterocyclic structure (however, monomer M2 does not include monomers represented by formula 1 below).

[0020] [ka]

[0021] In formula 1, R1~R 10 Each of these independently represents a hydrogen atom or an organic group.

[0022] A second aspect of the curable composition according to this disclosure comprises a thermally conductive filler, monomer M1, monomer C, polymerization initiator D, and dispersant E. Monomer M1 comprises a monomer consisting of a (meth)acryloyl group and a residue having a heterocyclic structure. Monomer M2 includes a monomer consisting of a (meth)acryloyl group and a residue that does not have a heterocyclic structure (however, monomer M2 does not include the monomer represented by formula 1 above).

[0023] The curable composition relating to this disclosure, having the above-described structure, can produce a cured product with excellent adhesion and flexibility. The reason for this is not clear, but it is presumed to be as follows; however, the following presumption is not intended to be interpreted restrictively to the lubricating oil composition relating to this disclosure, but is explained as an example.

[0024] The monomers M1 and M2 contained as curing components in the curable composition according to this disclosure are both acrylic monomers, and a cured product with excellent adhesion is obtained. Furthermore, since the monomer represented by formula 1 included as monomer M1 in the curable composition of the first embodiment undergoes cyclopolymerization, the cured product of the curable composition contains a polymer having a heterocyclic structure. Also, since the monomer consisting of a (meth)acryloyl group and a residue without a heterocyclic structure included as monomer M1 in the curable composition of the second embodiment contains a residue with a heterocyclic structure, the cured product of the curable composition contains a polymer having a heterocyclic structure. Because the cured product contains a polymer having a heterocyclic structure, it is presumed that the cured product obtained from the curable composition according to this disclosure will have excellent adhesion and appropriate flexibility.

[0025] The following describes each component contained in the curable composition relating to this disclosure.

[0026] <Thermal conductive filler> The curable composition relating to this disclosure contains a thermally conductive filler. The material of the thermally conductive filler is not particularly limited and includes zinc oxide, magnesium oxide, aluminum oxide, boron nitride, aluminum nitride, carbon, etc. From the viewpoint of insulation, high thermal conductivity, and proven track record as a thermally conductive filler, it is preferable that the thermally conductive filler contains at least one selected from aluminum nitride, zinc oxide, magnesium oxide, and aluminum oxide, more preferably aluminum nitride or zinc oxide, and even more preferably zinc oxide from the viewpoint of dispersibility and viscosity of the curable composition.

[0027] The thermally conductive filler may be a surface-treated thermally conductive filler. Surface-treated thermally conductive fillers can improve affinity with other components, contributing to lower viscosity and improved thermal conductivity.

[0028] The surface treatment of the thermally conductive filler is not particularly limited and may be a physical or chemical treatment. Known treatments that can treat the surface of the particles constituting the thermally conductive filler can be applied. For surface treatment, it is preferable to use a surface treatment agent.

[0029] Examples of surface treatment agents include silane-based coupling agents, titanium-based coupling agents, carboxylic acid-based coupling agents, phosphate-based coupling agents, fatty acids, polymer compounds, surfactants, and oils and fats.

[0030] From the viewpoint of dispersibility, it is preferable that the thermally conductive filler is surface-treated with a silane-based coupling agent as a surface treatment agent.

[0031] -Content- The content of the thermally conductive filler is preferably 87% by mass or more, more preferably 90% to 98% by mass, and even more preferably 92% to 96% by mass, based on the total mass of the composition. Furthermore, the content of the thermally conductive filler is preferably 40% by volume or more, more preferably 47% to 80% by volume, and even more preferably 60% to 80% by volume, based on the total volume of the curable composition. By keeping the thermally conductive filler content within the above range, high thermal conductivity can be achieved.

[0032] <Monomer M1> The curable composition relating to this disclosure contains monomer M1. Monomer M1 includes monomers represented by the following formula 1 (hereinafter also referred to as "monomer M1a") and monomers consisting of a (meth)acryloyl group and a residue having a heterocyclic structure (hereinafter also referred to as "monomer M1b"). Polymers derived from monomer M1 include polymers containing a heterocyclic structure within the molecule, regardless of whether monomer M1a or monomer M1b is used.

[0033] <<Monomer represented by formula 1>> The curable composition of the first embodiment contains a monomer represented by the following formula 1 (monomer M1a) as monomer M1. The curable composition of the first embodiment may contain only one type of monomer M1a, or it may contain two or more types.

[0034] [ka]

[0035] In formula 1, R1~R 10 Each of these independently represents a hydrogen atom or an organic group. In this disclosure, "organic group" means a functional group containing one or more carbon atoms.

[0036] R1~R 10 Examples of organic groups represented by include alkyl groups, alkyl ester groups, alkyl hydroxy groups, alkyl carboxyl groups, alkyl carbonyl groups, alkyl amino groups, alkyl cyano groups, and alkyl sulfo groups.

[0037] Among these, as monomer M1a, in formula 1, R1 represents the group represented by the following formula 2 (i.e., a methyl ester group), and R2~R 10 It is more preferable that all of these compounds represent hydrogen atoms (i.e., methyl 2-allyloxymethylacrylate).

[0038] [ka]

[0039] In equation 2, * represents the bonding position.

[0040] In the curable composition of the first embodiment, the content of monomer M1 is preferably 0.5% to 5% by mass, and more preferably 0.75% to 3% by mass, based on the total mass of the curable composition.

[0041] <<A monomer consisting of a (meth)acryloyl group and a residue having a heterocyclic structure>> The curable composition of the second embodiment contains a monomer (monomer M1b) as monomer M1, which consists of a (meth)acryloyl group and a residue having a heterocyclic structure. The curable composition of the second embodiment may contain only one type of monomer M1b, or it may contain two or more types.

[0042] Monomer M1b may be a monomer having one or more (meth)acryloyl groups in one molecule, and preferably a monomer having one (meth)acryloyl group in one molecule.

[0043] From the viewpoint of curability, the (meth)acryloyl group of monomer M1b is preferably an acryloyl group, and from the viewpoint of low skin irritation and flexibility, it is preferably a methacryloyl group.

[0044] In the heterocyclic residues of monomer M1b, examples of heterocyclic structures include tetrahydrofuran rings, azetidine rings, oxetane rings, thietan rings, diazetidine rings, dioxetane rings, dithietan rings, borolan rings, borol rings, pyrrolidine rings, pyrrole rings, furan rings, phosphorane rings, phosphole rings, tetrahydrotiphophene rings, imitazolidine rings, imidazole rings, oxazolidine rings, oxazole rings, thiazolidined rings, thiazole rings, dioxolane rings, diotilane rings, piperidine rings, pyridine rings, tetrahydropyran rings, pyran rings, phosphinan rings, phospholine rings, thian rings, thiopyran rings, piperazine rings, diazine rings, morpholine rings, oxazine rings, thiomorpholine rings, thiadin rings, dioxane rings, dioxin rings, dithiane rings, dithiine rings, etc., with tetrahydrofuran rings being preferred.

[0045] A preferred residue having a heterocyclic structure in monomer M1b is, for example, a tetrahydrofurfuryl group.

[0046] As for monomer M1b, for example, from the viewpoint of achieving both adhesion and flexibility, tetrahydrofurfuryl acrylate or tetrahydrofurfuryl methacrylate are preferred.

[0047] In the curable composition of the second embodiment, the content of monomer M1 is preferably 0.5% to 5% by mass, and more preferably 0.75% to 3% by mass, based on the total mass of the curable composition.

[0048] <Monomer M2> The curable composition relating to this disclosure contains monomer M2. Monomer C is a monomer consisting of a (meth)acryloyl group and a residue that does not have a heterocyclic structure (however, monomer M2 does not include the monomer represented by formula 1 above).

[0049] Monomer M2 may be a monomer having one (meth)acryloyl group in one molecule, or it may be a monomer having two or more (meth)acryloyl groups in one molecule.

[0050] In monomer M2, residues that do not have a heterocyclic structure include hydroxyl groups and organic groups that do not have a heterocyclic structure.

[0051] In monomer M2, as residues that do not have a heterocyclic structure, organic groups with a total number of carbon atoms of 12 or more (preferably 12 to 40, more preferably 12 to 32) are preferred from the viewpoint of imparting flexibility to the cured product.

[0052] Examples of monomer M2 include linear, branched, or cyclic alkyl (meth)acrylates, acrylic acid, and the like.

[0053] As for the monomer M2, in certain embodiments, from the perspective of achieving both heat resistance and flexibility, the monomer may include a monomer having one or more (meth)acrylate groups in one molecule, preferably includes a monomer having a linear, branched or cyclic alkyl (meth)acrylate, and more preferably includes a monomer represented by the following formula 3.

[0054]

Chemical formula

[0055] In formula 3, R 1 represents a linear, branched or cyclic alkyl group having 1 to 50 carbon atoms, and R 2 represents a hydrogen atom or a methyl group.

[0056] In formula 3, the alkyl group for R 1 may be linear, branched or cyclic. Furthermore, the alkyl group may have a substituent. Examples of the substituent include a carboxy group, a hydroxy group, an amino group, an aryl group, etc., but it is preferably a carboxy group or a hydroxy group, and more preferably a hydroxy group.

[0057] From the perspective of achieving both heat resistance and flexibility, the number of carbon atoms of the alkyl group for R 1 is preferably 2 to 30, more preferably 5 to 25, still more preferably 10 to 25, and particularly preferably 12 to 18. Here, when the alkyl group has a substituent containing carbon atoms, the number of carbon atoms means the total number of carbon atoms including the number of carbon atoms of the substituent.

[0058] From the perspective of achieving both heat resistance and flexibility, in formula (3), R 1 is preferably a linear, branched or cyclic alkyl group having a total of 2 to 30 carbon atoms, which may have a substituent, and more preferably a linear, branched or cyclic alkyl group having a total of 2 to 25 carbon atoms, which may have a hydroxy group.

[0059] Examples of monomer C include lauryl (meth)acrylate, isostearyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, decyltetradecanol monomethacrylate, 2-ethylhexyl methacrylate, 2-hydroxypropyl methacrylate, 2-methacryloyloxyethyl succinate, and isobornyl acrylate.

[0060] In formula 3, R 2 This is a hydrogen atom or a methyl group, and a methyl group is preferred.

[0061] In one embodiment, monomer M2 may include monomers having two or more (meth)acrylate groups in one molecule. Examples of monomers having two or more (meth)acrylate groups in one molecule include 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.

[0062] In one embodiment, monomer M2 may include a monomer having two or more (meth)acrylate groups in one molecule, from the viewpoint of achieving both heat resistance and flexibility. Preferably, the monomer having two or more (meth)acrylate groups in one molecule is a compound having two and / or three (meth)acrylate groups in one molecule, more preferably a compound having two (meth)acrylate groups in one molecule, and even more preferably a compound represented by the following formula 4.

[0063] [ka]

[0064] In formula 4, R B1 R represents an alkylene group with 1 to 5 carbon atoms. B2 and R B3 Each of these independently represents either a hydrogen atom or a methyl group, and n represents an integer of 4 or greater. R B1 The alkylene group having 1 to 5 carbon atoms, represented by , may be linear or branched. From the standpoint of flexibility, R B1 The alkylene group represented is preferably a branched alkylene group having 2 to 5 carbon atoms, more preferably a linear or branched alkylene group having 2 to 4 carbon atoms, and even more preferably a branched alkylene group having 3 or 4 carbon atoms. R B2 and R B3 Each of these is preferably a methyl group. n is preferably 4 to 25, more preferably 4 to 10, and even more preferably 3 to 8.

[0065] From the viewpoint of flexibility and shape stability, in Equation 4, R B1 R is a branched alkylene group having 2 to 5 carbon atoms (more preferably a linear or branched alkylene group having 2 to 4 carbon atoms, and even more preferably a branched alkylene group having 3 or 4 carbon atoms), B2 and R B3The group is a methyl group, and n is preferably 4 to 25 (more preferably 4 to 10, and even more preferably 3 to 8).

[0066] In one embodiment, monomer M2 preferably comprises at least one monomer selected from monomers having one (meth)acrylate group in one molecule, and at least one monomer selected from monomers having two or more (meth)acrylate groups in one molecule.

[0067] In the curable composition according to this disclosure, the monomer M2 content is preferably 0.5% to 20% by mass, and more preferably 1% to 15% by mass, based on the total mass of the curable composition.

[0068] In the curable composition according to this disclosure, from the viewpoint of achieving both adhesion and flexibility, the content of monomer M1 is preferably 5% by mass or more and 35% by mass or less, and more preferably 10% by mass or more and 30% by mass or less, based on the total content of monomer M1 and monomer M2.

[0069] <Polymerization initiator> The curable composition relating to this disclosure contains a polymerization initiator. As polymerization initiators, compounds that generate polymerization initiator species such as radicals and cations in response to light, heat, or both energy, can be appropriately selected and used, such as known thermal polymerization initiators and known photopolymerization initiators. As a polymerization initiator, a radical polymerization initiator is preferred from the viewpoint of reactivity with monomers M1 and M2, a peroxide that generates free radicals upon heat is more preferred, and an organic peroxide that generates free radicals upon heat is even more preferred.

[0070] Examples of organic peroxides include isobutyl peroxide, α,α'bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, di-s-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, di-2-ethoxyethyl peroxydicarbonate, and di(ethylhexyl)peroxy Sidic carbonate, t-hexyl peroxyneodecanoate, dimethoxybutyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, succinic peroxide, 2,5-dimethyl-2,5-di (2-ethylhexanoyl)hexane, 1-cyclohexyl-1-methylethyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylhexanoate, 4-methylbenzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, m-toluyl benzoyl peroxide, benzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-bis(t-butylperoxy)2-methylcyclohexane, 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, 1,1 -Bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexanone, 2,2-bis(4,4-dibutylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)cyclododecane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(m-toluylperoxy)hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl carbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxyacetate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4,4-bis(t-butylperoxy)valerate, di-t-butylperoxyisophthalate, α,α'bis(t-butylperoxy)diisopropylbenzene, dicumylperoxy Examples include oxides, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide, etc. Among these, from the viewpoint of reactivity, the organic peroxide is preferably at least one compound selected from the group consisting of benzoyl peroxide, t-butyl peroxy-2-ethylhexyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, and cumene hydroperoxide.

[0071] The content of the polymerization initiator is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 0.5 parts by mass or more and 4 parts by mass or less, based on 100 parts by mass of the total monomer content contained in the curable composition.

[0072] <Dispersant> This disclosure contains a curable composition and a dispersant. There are no particular restrictions on the dispersants, and examples include anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, polymeric surfactants, alcohols, compounds having carboxyl groups such as fatty acids, metal soaps, fatty acid oligomer compounds, fluorinated surfactants, and boron-based surfactants.

[0073] Among the above dispersants, dispersant E is at least one compound selected from the group consisting of nonionic surfactants, compounds having a carboxyl group, and metal soaps. It is preferable that the compound has a carboxyl group, and more preferably that it has a carboxyl group.

[0074] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, polyglycerin fatty acid esters, polyglycerin fatty acid ethers, polyglycerin monoalkyl ethers, sucrose fatty acid esters, polyoxyethylene alkylamines, polyethylene glycol polypropylene glycol block copolymers, acetylene glycol, and polyoxyethylene adducts of acetylene glycol.

[0075] The compounds having a carboxyl group are not particularly limited and may be fatty acids having one carboxyl group and one hydrocarbon group in one molecule, or compounds having two or more carboxyl groups in one molecule.

[0076] Examples of compounds containing a carboxyl group include aromatic carboxylic acids and fatty acids having an aliphatic hydrocarbon group with 12 to 22 carbon atoms. Furthermore, examples of compounds having carboxyl groups include polycarboxylic acids (polycarboxylic acids) having two or more carboxyl groups in one molecule, such as oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, and adipic acid; polycarboxylic acid salts such as alkylamine salts, alkylammonium salts, polycarboxylic acid polyaminoamides, sodium polycarboxylic acid salts, ammonium polycarboxylic acid salts, and amino alcohol polycarboxylic acid salts; and polycarboxylic acid copolymers.

[0077] Examples of metal soaps include metal salts of higher fatty acids such as calcium stearate, potassium oleate, and calcium oleate.

[0078] Among the above dispersants, the dispersant is preferably a compound having a carboxyl group, and more preferably a fatty acid having an aliphatic hydrocarbon group with 12 to 22 carbon atoms. Examples of fatty acids having an aliphatic hydrocarbon group with 12 to 22 carbon atoms include stearic acid, oleic acid, palmitic acid, myristic acid, and lauric acid, with oleic acid being preferred.

[0079] The dispersant content is preferably 0.1 parts by mass or more and 1.0 part by mass or less, more preferably 0.1 parts by mass or more and 0.8 parts by mass or less, and particularly preferably 0.1 parts by mass or more and 0.5 parts by mass or less, per 100 parts by mass of thermally conductive filler.

[0080] <Plasticizer> The curable composition relating to this disclosure may contain a plasticizer. There are no particular restrictions on the plasticizer as long as it is a compound that does not form a crosslinked structure with monomers, etc. Examples include polymers used as plasticizers, fatty acid ester compounds having unsaturated hydrocarbon groups, aromatic carboxylic acid ester compounds, as well as oils containing fatty acids and aromatic carboxylic acids having unsaturated hydrocarbon groups.

[0081] Examples of polymers used as plasticizers include acrylic polymers, polyester polymers, polyurethane polymers, and silicone polymers, but acrylic polymers are preferred from the viewpoint of heat resistance and flexibility of the resulting cured product.

[0082] As an acrylic polymer, it is preferable that it contains structural units formed from acrylic acid esters, from the viewpoint of heat resistance. Alkyl (meth)acrylate is preferred as the (meth)acrylic ester. Examples of meth)acrylic esters include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate. Furthermore, the alkyl acrylate may be an unfunctional alkyl acrylate, or it may have a functional group such as a carboxyl group or a hydroxyl group. The functional group of the alkyl acrylate is preferably a hydroxyl group.

[0083] Acrylic polymers are given by the following formula (P AC The polymer may have a structure represented by ).

[0084] [ka]

[0085] Formula (P AC ), R p represents a hydrogen atom or an alkyl group. Formula (P AC In this compound, the alkyl group may have substituents. Examples of substituents include carboxyl groups, hydroxyl groups, and amino groups. Carboxyl groups or hydroxyl groups are preferred substituents, and hydroxyl groups are more preferred. As the alkyl group, saturated alkyl groups are preferred, such as methyl, ethyl, propyl, butyl, and hexyl groups. Among these, alkyl groups having 1 to 4 carbon atoms are more preferred.

[0086] When the plasticizer contained in the curable composition according to this disclosure is a polymer, from the viewpoint of the heat resistance and flexibility of the resulting cured product, it is preferable that the polymer has a glass transition temperature of -20°C or lower, and more preferably that it is an acrylic polymer with a glass transition temperature of -20°C or lower. preferable.

[0087] When the plasticizer contained in the curable composition according to this disclosure is a polymer, from the viewpoint of the heat resistance and flexibility of the resulting cured product, it is preferable that the polymer has a glass transition temperature of -90°C or higher and -20°C or lower, and more preferably that it is an acrylic polymer with a glass transition temperature of -90°C or higher and -20°C or lower.

[0088] The glass transition temperature (Tg) of a polymer can be determined by examining the inflection point of the DSC curve, which is measured using a differential thermal analyzer (DSC).

[0089] When the plasticizer contained in the curable composition according to this disclosure is a compound other than a polymer, it is preferable that the compound has a softening temperature of -20°C or lower, and more preferably a compound with a softening temperature of -25°C or lower, from the viewpoint of the heat resistance and flexibility of the resulting cured product. The softening temperature of compounds other than polymers can be determined by examining the inflection point of the DSC curve, which is measured using a differential thermal analyzer (DSC).

[0090] Examples of fatty acid ester compounds having an unsaturated hydrocarbon group include ester compounds of palmitoleic acid, oleic acid, linoleic acid, and linolenic acid. Examples of aromatic carboxylic acid ester compounds include ester compounds such as phthalic acid, terephthalic acid, benzoic acid, and trimellitic acid.

[0091] When the curable composition according to this disclosure contains a plasticizer F, from the viewpoint of high-temperature stability, the plasticizer F preferably contains an aromatic carboxylic acid ester compound, and more preferably contains a trimellitic acid ester.

[0092] In a curable composition, the plasticizer may be present as a single type or as two or more types.

[0093] The plasticizer content is preferably 0.1 parts by mass or more and 3 parts by mass or less, more preferably 0.1 parts by mass or more and 2.5 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 2.0 parts by mass or less, per 100 parts by mass of thermal conductive filler.

[0094] <Other additives> The curable composition relating to this disclosure may, if necessary, contain components other than the thermally conductive filler, monomer M1, monomer M2, polymerization initiator, dispersant, and plasticizer described above (hereinafter also referred to as "other additives"). Other additives that can be appropriately blended include reducing agents, antioxidants, corrosion inhibitors, rust inhibitors, and rheology control agents (viscosity modifiers). Other additives may be used individually or in combination of two or more.

[0095] <Reducing agent> The curable composition relating to this disclosure may optionally contain a reducing agent. When applying the curable composition according to this disclosure to a two-component curable composition described later, it is preferable to include a reducing agent in one of the compositions. Adding a reducing agent facilitates the decomposition of polymerization initiator D (e.g., peroxide), allowing the polymerization reaction to proceed even under low-temperature conditions.

[0096] The reducing agent is not particularly limited as long as it can promote the decomposition of the polymerization initiator, and known reducing agents used in combination with polymerization initiators can be used, but from the viewpoint of promoting the decomposition of the polymerization initiator, a metal compound-based reducing agent is preferred.

[0097] Examples of metal compound reducing agents include stannous oxide, dioctyl tin dilaurate, dibutyl tin dilaurate, dibutyl tin diacetate, zinc naphthenate, antimony trichloride, and Examples include lium oleate, sodium O-phenylphenate, bismuth nitrate, ferric chloride, tetra-n-butyltin, tetra(2-ethylhexyl) titanate, cobalt 2-ethylhexoate, and iron 2-ethylhexoate.

[0098] When the curable composition according to this disclosure contains a reducing agent, from the viewpoint of curing speed, the content of the reducing agent is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 2 parts by mass or more and 9 parts by mass or less, based on 100 parts by mass of the total content of monomers contained in the curable composition. The reducing agent may be used alone or in combination of two or more types.

[0099] <Antioxidant> Examples of antioxidants include phenolic antioxidants, amine antioxidants, and phosphite antioxidants.

[0100] <Corrosion inhibitor> Examples of corrosion inhibitors include benzotriazole, toltriazole, thiadiazole, and benzimidazole.

[0101] <Rust Inhibitor> Examples of rust inhibitors include metal sulfonate salt compounds and sorbitan compounds.

[0102] <Rheology control agent> In this disclosure, the rheology control agent refers to an additive that imparts non-Newtonian properties to changes in shear rate, and is an additive that provides flow characteristics such as high shear viscosity in the low shear rate range and low shear viscosity in the high shear rate range.

[0103] The rheology control agent may be an inorganic compound-based rheology control agent or an organic compound-based rheology control agent. Examples of inorganic compound-based rheology control agents include fumed silica, bentonite, mica, and kaolin. Examples of organic compound-based rheology control agents include urea-modified polymers, urethane-modified polymers, castor oil wax, polyethylene wax, polyamide wax, and fatty acid amide wax. Among these, inorganic compound-based rheology control agents are preferred, with fumed silica or bentonite being more preferred, and bentonite being even more preferred. When using fumed silica, it is preferable that the surface is made hydrophobic by a silane coupling agent or other surface modifier. When using bentonite, organically modified bentonite with a quaternary ammonium salt or other organic modifier is preferably used.

[0104] There are no particular restrictions on the amount of rheology control agent contained, and it can be set as appropriate.

[0105] [Form of the curable composition] The curable composition according to this disclosure is preferably a one-component curable composition that uses only one type of curable composition when applied to a substrate, heating element, etc. The curable composition according to this disclosure may also be a two-component curable composition that uses a mixture of two types of curable compositions.

[0106] [Method for producing a curable composition] The method for producing the curable composition according to this disclosure is not particularly limited. The curable composition according to this disclosure can be produced, for example, by the following method. In one embodiment, the curable composition according to the disclosure is obtained by placing a thermally conductive filler, monomers M1 and M2, a polymerization initiator, a dispersant, a plasticizer, and other additives into a stirring vessel and stirring and mixing them. For stirring and mixing, known stirrers and the like can be used.

[0107] In the method for producing a curable composition, when other additives are added, stirring is sufficient for a period of time during which the other additives can dissolve or disperse. The other additives may be added to the stirring container together with the other components, or they may be added after the other components have been mixed.

[0108] (cured product) The cured product relating to this disclosure is a cured product of the curable composition relating to this disclosure. The method for curing the curable composition is not limited and can be appropriately selected from commonly used methods. Examples of curing methods include irradiation with active energy rays and heating, but curing by heating is preferred. When curing the curable composition according to this disclosure by heating, the heating temperature is preferably 60°C or higher, and more preferably 70°C or higher. The heating time is preferably 1 minute to 120 minutes.

[0109] Furthermore, the curable composition relating to this disclosure may be cured by reacting with moisture in the air, or by curing at room temperature.

[0110] The thermal conductivity of the cured product according to this disclosure is preferably 0.5 (W·m / K) to 50 (W·m / K), preferably 1 (W·m / K) to 20 (W·m / K), and more preferably 3 (W·m / K) to 20 (W·m / K), from the viewpoint of flexibility, shape stability, and suppression of changes in thermal conductivity.

[0111] The adhesive properties of the cured product according to this disclosure are preferably such that the tensile shear stress measured in accordance with JIS K 6850:1999 is 0.5 MPa or higher, more preferably 0.55 MPa or higher, and even more preferably 0.6 MPa or higher. The upper limit of the tensile shear stress is not particularly limited, but for example, it may be 5 MPa.

[0112] Regarding the flexibility of the cured product relating to this disclosure, from the viewpoint of stress relief to surrounding parts of the cured product, the Shore DO hardness measured in accordance with ASTM D2240 is preferably 85 or less, and more preferably 80 or less. As for the lower limit, for the reason of preventing pump-out, it is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more.

[0113] Shore DO hardness is a value measured using a spring-type hardness tester such as a durometer (registered trademark), and is the value measured immediately after pressing the hardness tester against the object being measured.

[0114] <Application> The curable composition according to this disclosure can be suitably used, for example, as a TIM (Thermal Injection Mixture) to fill recesses (gaps between heating elements and heat sinks) formed in a substrate. The cured product obtained from the curable composition according to this disclosure has excellent adhesion and flexibility, and can follow thermal expansion and contraction, thus efficiently dissipating heat, making it suitable for use as a gap filler. [Examples]

[0115] Next, the curable composition and cured product relating to this disclosure will be specifically described with reference to examples. However, the curable composition and cured product relating to this disclosure are not limited in any way by these examples.

[0116] (Examples 1-6 and Comparative Examples 1-9) Each component listed in the composition column of Table 1 or Table 2 was blended in the amounts specified in Table 1 or Table 2, and the mixture was prepared by mixing it at 2,000 rpm (revolutions per minute) for 2 minutes under atmospheric pressure using a rotational / revolving mixer (manufactured by Shinky Co., Ltd., product name: Awatori Rentaro ARV-310) to prepare a curable composition.

[0117] Details of each component listed in Table 1 or Table 2 are as follows:

[0118] <Thermal conductive filler> Zinc oxide 1: Zinc oxide type 1, volume average diameter D50; 0.6 μm (Sakai Chemical Industry Co., Ltd.) Zinc oxide 2: Calcined zinc oxide DW-4 (4μm) (Hakusui Tech Co., Ltd.) Zinc Oxide 3: Calcined Zinc Oxide Surface Treatment Product (12 μm) (Hakusui Tech Co., Ltd.)

[0119] <Monoma-M1> (Monoma-M1a) 2-(allyloxymethyl)methyl acrylate: AOMA (Nippon Shokubai Co., Ltd.) (Monoma-M1b) Tetrahydrofurfuryl acrylate: THFA (Tokyo Chemical Industries, Ltd.) Tetrahydrofurfuryl methacrylate: THFMA (Tokyo Chemical Industries, Ltd.)

[0120] <Monoma-M2> Decyltetradecanol monomethacrylate:NK ester ITEC (Shin-Nakamura Chemical Industry Co., Ltd.) Lauryl methacrylate:light ester L (Kyoeisha Chemical Co., Ltd.) 2-Hydroxyethyl Methacrylate: Light Ester HO-250(N) (Kyoeisha Chemical Co., Ltd.) 2-Ethylhexyl methacrylate:2-EHMA (Mitsubishi Gas Chemical Company, Inc.) 2-Hydroxypropyl Methacrylate: HPMA (Nippon Shokubai Co., Ltd.) 2-Hydroxybutyl Methacrylate: Light Ester HOB(n) (Kyoeisha Chemical Co., Ltd.) 2-Methacryloyloxyethyl succinate:light ester HO-MS(N) (Kyoeisha Chemical Co., Ltd.) Isobornyl acrylate: Isobornyl acrylate (Daicel Ornex Co., Ltd.) Polypropylene glycol #400 dimethacrylate:9PG (Shin-Nakamura Chemical Industry Co., Ltd.)

[0121] <Dispersant> Oleic acid: Oleic acid (NOF Corporation) <Polymerization initiator> 1,1,3,3-Tetramethylbutyl peroxy-2-ethylhexanoate:perocta-O (NOF Corporation) <Plasticizer> Trimellitic acid mixed linear alkyl ester: C-880 NB, manufactured by ADEKA Corporation) <Rheology control agent> Organically modified bentonite: CLAYTONE-40 (BIG CHEMI Japan Co., Ltd.) <Coloring pigments> Copper phthalocyanine: Cyanine Blue 4920 (Dainichi Seika Kogyo Co., Ltd.)

[0122] In the composition column of Tables 1 and 2, a blank space indicates that the target component is not present. In Tables 1 and 2, "thermal conductive filler filling rate" refers to the percentage (mass %) of the mass of thermal conductive filler relative to the total amount of curable composition. In Tables 1 and 2, the term "binder component" refers to the liquid component in a curable composition containing monomers, dispersants, polymerization initiators, and plasticizers. In Tables 1 and 2, "-" indicates that the corresponding value cannot be calculated.

[0123] -evaluation- The following evaluations were performed using the obtained curable composition.

[0124] <Tensile shear stress: Adhesion> The tensile shear stress of the curable composition was measured in accordance with JIS K 6850:1999. Two aluminum plates (A1050P-H24) measuring 25mm wide x 100mm long x 1.6mm thick were prepared. Two aluminum plates were bonded together using a curable composition, covering an area of ​​25 mm width x 12.5 mm length x 250 μm thickness. The curable composition was then cured at 80°C for 30 minutes. Next, using a tensile testing machine (product name: MX2-1000N-FA, manufactured by IMADA Co., Ltd.), each of the two aluminum plates was pulled in the shear direction at a tensile speed of 10 mm / min, and the tensile shear stress was calculated from the maximum strength measured. The measurement results are shown in Table 1 or Table 2. If the tensile shear stress is 0.5 MPa or higher, this evaluation is deemed to have passed.

[0125] <Hardness: Flexibility> -Softness after hardening: Shore DO hardness- The curable composition was molded into a 50mm x 20mm x 6mm (6mm thick) shape, and a cured product was obtained after curing at 80°C for 30 minutes. The softness of the obtained cured product was measured using a durometer (product name: GS-752G, manufactured by Teclock Co., Ltd.) in accordance with ASTM D 2240. The measurement results are shown in Table 1 or Table 2. If the Shore DO hardness is 85 or less, this evaluation was deemed to be a passing grade.

[0126] <compatibility> The binder component (i.e., the liquid component in the curable composition, including monomers, dispersants, polymerization initiators, and plasticizers) was mixed with other components, and its compatibility was evaluated as kneadability. If kneadability was achieved, the evaluation was deemed satisfactory. The results are shown in Table 1 or Table 2, with "acceptable" indicating that kneadability was possible and "unacceptable" indicating that kneadability was not possible.

[0127] <Overall Evaluation (Performance Pass / Fail)> If all three evaluation criteria—tensile shear stress, hardness, and compatibility—passed, the overall evaluation (performance pass / fail) was determined to be a pass. The results are shown in Table 1 or Table 2.

[0128] [Table 1]

[0129] [Table 2]

[0130] As shown in Table 1, the cured products obtained from the curable compositions of the examples exhibited excellent adhesion and flexibility. In contrast, as shown in Table 2, the comparative curable compositions failed to meet either the adhesion or flexibility requirements, failing to achieve both.

Claims

1. It contains a thermally conductive filler, monomer M1, monomer M2, polymerization initiator, and dispersant. Monomer M1 comprises a monomer represented by the following formula 1, Monomer M2 includes monomers consisting of a (meth)acryloyl group and residues that do not have a heterocyclic structure (however, monomer M2 does not include monomers represented by formula 1 below). Curable composition. 【Chemistry 1】 In formula 1, R １ ~R １０ Each of these independently represents a hydrogen atom or an organic group.

2. It contains a thermally conductive filler, monomer M1, monomer M2, polymerization initiator, and dispersant. Monomer M1 comprises a monomer consisting of a (meth)acryloyl group and a residue having a heterocyclic structure. Monomer M2 includes a monomer consisting of a (meth)acryloyl group and a residue that does not have a heterocyclic structure (however, monomer M2 does not include the monomer represented by formula 1 below). Curable composition. 【Chemistry 2】 In formula 1, R １ ~R １０ Each of these independently represents a hydrogen atom or an organic group.

3. In formula 1, R １ R represents the group shown in the following formula 2, ２ ~R １０ The curable composition according to claim 1, wherein each of these terms represents a hydrogen atom. 【Transformation 3】 In equation 2, * indicates the bonding position.

4. The curable composition according to any one of claims 1 to 3, wherein the content of monomer M1 is 5% by mass or more and 35% by mass or less on a mass basis, relative to the total content of monomer M1 and monomer M2.

5. The curable composition according to any one of claims 1 to 3, wherein the content of monomer M1 is 10% by mass or more and 30% by mass or less on a mass basis, relative to the total content of monomer M1 and monomer M2.

6. The curable composition according to claim 1 or claim 2, wherein in monomer M2, the residue that does not have a heterocyclic structure is an organic group with a total of 12 or more carbon atoms.

7. The curable composition according to claim 1 or claim 2, wherein the thermally conductive filler comprises zinc oxide.

8. A cured product of the curable composition according to claim 1 or claim 2.

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