JP2022157070A - Curable composition and cured product - Google Patents

Abstract

To provide a curable composition that is less prone to powdering after curing, or a cured product thereof.SOLUTION: A curable composition contains an anionic dispersant (A) with an OH value of 40 mgKOH-160 mgKOH/g, a monomer having a methacryloyl group (B), a polymerization initiator (D), a plasticizer (E), and a thermally conductive filler (F). The content of the anionic dispersant (A) is 0.1 mass%-1.0 mass% relative to the total mass of the composition. There is also provided a cured product.SELECTED DRAWING: None

Description

The present disclosure relates to curable compositions and cured products.

In recent years, the performance of personal computers, mobile phones, personal digital assistants; electronic devices such as PDAs; light emitting diodes; LEDs, Electronic Luminescent; depends on As described above, the amount of heat generated increases remarkably as the performance of arithmetic elements or light-emitting elements improves, and how to dissipate heat in electronic devices, lighting devices, and display devices has become an important issue. As a countermeasure against heat, TIM (Thermal Interface Materials; thermally conductive material) is placed between the heat generating element and the heat dissipating element in order to transmit the heat generated by the arithmetic element or the light emitting element to the heat dissipating element without loss and dissipate the heat through the heat dissipating element. measures have been taken to provide Heat-dissipating sheets, thermally conductive greases, gap fillers, and the like are known as TIMs that are generally used, but attention is focused on gap fillers, which are paste-like at the beginning and harden after being applied and become solid.

As a gap filler excellent in flexibility, shape stability, and thermal conductivity, for example, Patent Document 1 discloses a compound (A) having one (meth)acrylate group in one molecule and ( A curable composition comprising a compound (B) having two or more meth)acrylate groups, a polymerization initiator (C), a dispersant (D), and a thermally conductive filler (E) containing zinc oxide. is disclosed.

WO2020/149193

A problem to be solved by an embodiment of the present disclosure is to provide a curable composition that is excellent in suppressing dusting after curing.
Another problem to be solved by another embodiment of the present disclosure is to provide a cured product that is excellent in suppressing powder blowing.
In the present specification, "powder blowing" means peeling of the thermally conductive filler (F) from the surface of the curable composition after curing, and "suppression of puffing" means after curing. Means suppression of peeling of the thermally conductive filler (F) from the surface of the curable composition

Means for solving the above problems include the following embodiments.
<1> an anionic dispersant (A) having an OH value of 40 mgKOH to 160 mgKOH/g;
(Meth) a monomer (B) having an acryloyl group;
a polymerization initiator (D);
a plasticizer (E);
a thermally conductive filler (F);
including
A curable composition in which the content of the anionic dispersant (A) is 0.1% by mass to 1.0% by mass relative to the total mass of the composition.
<2> The curable composition according to <1>, wherein the monomer (B) contains a compound represented by the following formula (1).

In formula (1), R ¹ represents an alkyl group having 1 to 50 carbon atoms, and R ² represents a hydrogen atom or a methyl group.
<3> The curable composition according to <1> or <2>, wherein the monomer (B) contains a compound represented by the following formula (2).

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

<4> The curable composition according to any one of <1> to <3>, wherein the anionic dispersant (A) contains an acid group and a salt thereof.
<5> The curable composition according to <4>, wherein the acid group is a carboxy group or a phosphoric acid group.
<6> The curable composition according to any one of <1> to <5>, wherein the anionic dispersant (A) has a molecular weight of less than 1,000.
<7> The curable composition according to any one of <1> to <6>, wherein the plasticizer (F) contains an acrylic polymer or a trimellitate ester.
<8> The content ratio of the anionic dispersant (A) to the thermally conductive filler (F) (anionic dispersant (A)/thermally conductive filler (F)) is 0.001 on a mass basis. 0.015, the curable composition according to any one of <1> to <7>.
<9> The curable composition according to any one of <1> to <8>, wherein the thermally conductive filler (F) contains zinc oxide.
<10> Any one of <1> to <9>, wherein the content of the thermally conductive filler (F) is 70% by mass to 98% by mass with respect to the total mass of the composition. Curable composition.
<11> A cured product of the curable composition according to any one of <1> to <10>.

According to one embodiment of the present disclosure, a curable composition is provided that is excellent in suppressing dusting after curing. Moreover, according to another embodiment of the present disclosure, a cured product that is excellent in suppressing powder blowing is provided.

Hereinafter, embodiments for implementing the curable composition and the cured product according to the present disclosure will be described in detail.
In the present disclosure, "-" representing a numerical range represents a range including the numerical values described as the upper and lower limits thereof. In addition, when only the upper limit value in the numerical range represented by "-" is described in units, it means that the lower limit value is also in the same unit.
In the present disclosure, when there are multiple types of substances corresponding to each component in the composition, the content rate or content of each component in the composition is means the total content or content of
In the numerical ranges described step by step in the present disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described step by step.
In the numerical ranges described in the present disclosure, upper or lower limits described in a certain numerical range may be replaced with values shown in Examples.

In the present disclosure, "(meth)acrylic" is a term used as a concept that includes both acrylic and methacrylic, and "(meth)acryloyl" is a term that is used as a concept that includes both acryloyl and methacryloyl. be.
In the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.
In the present disclosure, each ingredient in the composition means the total amount of the corresponding substances present in the composition when there is more than one of each ingredient in the composition, unless otherwise specified.
In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.
In this disclosure, "JIS" is used as an abbreviation for Japanese Industrial Standards.

(Curable composition)
The curable composition according to the present disclosure includes an anionic dispersant (A) having an OH value of 40 mgKOH/g to 160 mgKOH/g, a (meth)acryloyl group-containing monomer (B), and a polymerization initiator (D). , a plasticizer (E), and a thermally conductive filler (F), and the content of the anionic dispersant (A) is 0.1% by mass to 1.0% by mass relative to the total mass of the composition. It is 0% by mass.
Since the curable composition according to the present disclosure has the above configuration, it is excellent in suppressing dusting after curing.
In the present specification, "powder blowing" means peeling of the thermally conductive filler (F) from the surface of the curable composition after curing, and "suppression of puffing" means after curing. It means suppression of peeling of the thermally conductive filler (F) from the surface of the curable composition.

Dispersants such as oleic acid and selachyl alcohol contained in the curable composition used for the gap filler have good wettability with respect to the filler and contribute to reducing the viscosity of the composition. , a monomer having a (meth)acryloyl group, a plasticizer component, etc.), powdering tends to occur after curing. For this reason, there is a demand for further improvement in powder blowing of the curable composition used for the gap filler.
Therefore, as a result of extensive studies by the inventors, in order to suppress dusting and maintain a low viscosity in the curable composition used for the gap filler, the dispersant has wettability with respect to the filler and phase with respect to components other than the filler. We have found that both solubility needs to be excellent, leading to the construction of the curable composition according to the present disclosure.
Although the detailed mechanism by which the above effects are obtained is unknown, it is presumed as follows.

Since the anionic dispersant (A) contained in the curable composition according to the present disclosure has a specific OH value, it has good wettability with the thermally conductive filler (F). Since the anionic dispersant (A) is contained in the composition in the range of the content of , it is speculated that it is excellent in suppressing peeling (powder blowing) of the thermally conductive filler (F) from the surface of the curable composition after curing.
Further, in the curable composition according to the present disclosure, the anionic dispersant (A) has a specific OH value and is contained in a specific amount in the composition, so it is optimal for the thermally conductive filler. In order to exhibit dispersibility, it is speculated that it is also excellent in maintaining the viscosity of the curable composition low (hereinafter also referred to as "low viscosity maintenance property").
Each configuration of the curable composition according to the present disclosure will be described below.

<Anionic dispersant (A)>
The curable composition according to the present disclosure includes an anionic dispersant (A) having an OH value of 40 mgKOH/g to 160 mgKOH/g (hereinafter sometimes simply referred to as "anionic dispersant (A)"). and the content of the anionic dispersant (A) is 0.1% by mass to 1.0% by mass relative to the total mass of the composition.
By including the anionic dispersant (A) having an OH value within the above range in the composition within the above content range, it is possible to suppress dusting after curing and maintain low viscosity.

The OH value of the anionic dispersant (A) is the mass (mg) of potassium hydroxide required to neutralize the acid groups (e.g., free fatty acids, resins having acid groups, etc.) contained in 1 g of the sample. and is obtained by the method described in JIS: K 0070-1992.

The OH value of the anionic dispersant (A) is preferably 50 mgKOH/g to 150 mgKOH/g from the viewpoint of suppressing powdering after curing and maintaining low viscosity, and 60 mgKOH/g to 140 mgKOH/g. more preferably 65 mgKOH/g to 135 mgKOH/g.

The anionic dispersant (A) is not particularly limited as long as it is a compound containing an anionic group used as a dispersant and has an OH value of 40 mgKOH/g to 160 mgKOH/g.
Examples of anionic groups contained in the anionic dispersant (A) include acid groups and salts thereof. The acid group includes a carboxy group, a sulfo group, a phosphoric acid group, a phosphonic acid group, and the like. From the viewpoint of suppressing dusting after curing and maintaining low viscosity, the acid group is preferably a carboxy group or a phosphoric acid group.
As the acid group salt, an alkali metal salt is preferable, and a sodium salt or a potassium salt is more preferable.
From the viewpoint of suppressing powdering after curing and maintaining low viscosity, the anionic dispersant (A) is preferably a compound containing an acid group and its salt, and a carboxy group or a phosphoric acid group and its salt. More preferably, it is a compound containing

Examples of compounds containing a phosphate group or a salt thereof include alkyl phosphates (e.g., sodium stearyl phosphate), alkyl ether phosphates (e.g., polyoxyethylene oleyl ether phosphate, and polyoxyethylene stearyl ether phosphate). ) and the like.
Among these, alkyl ether phosphoric acid and its salt are preferable, and polyoxyalkylene alkyl ether phosphoric acid and its salt are more preferable, from the viewpoint of suppressing dusting after curing and maintaining low viscosity.

Alkyl ether phosphates and salts thereof and polyoxyalkylene alkyl ether phosphates and salts thereof preferably have an alkyl group having 6 to 40 carbon atoms, more preferably an alkyl group having 8 to 30 carbon atoms, It is more preferable to have an aliphatic hydrocarbon group with 12 to 20 carbon atoms.

The polyoxyalkylene group in the polyoxyalkylene alkyl ether phosphoric acid and its salt includes, for example, a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group, or a group in which these groups are randomly bonded. Among these, the polyoxyalkylene group is preferably a polyoxyethylene (POE) group.

The compound containing a phosphoric acid group or a salt thereof is an alkyl group having 6 to 40 carbon atoms (preferably an alkyl group having 8 to 30 carbon atoms, more preferably an alkyl group having 8 to 30 carbon atoms, from the viewpoint of suppressing dusting after curing and maintaining low viscosity. is an aliphatic hydrocarbon group having 12 to 20 carbon atoms), or a polyoxyalkylene alkyl ether phosphoric acid and its salt, preferably an alkyl group having 6 to 40 carbon atoms ( An alkyl group preferably having 8 to 30 carbon atoms, more preferably an aliphatic hydrocarbon group having 12 to 20 carbon atoms. (preferably an alkyl group having 8 to 30 carbon atoms, more preferably an aliphatic hydrocarbon group having 12 to 20 carbon atoms) and a polyoxyethylene alkyl ether phosphoric acid having a poly Oxyethylene oleyl ether phosphate and salts thereof are particularly preferred.

The compound containing a carboxy group or a salt thereof is not particularly limited, and may be a fatty acid having one carboxy group and a hydrocarbon group in one molecule and a salt thereof, or two or more carboxy groups in one molecule. A compound having a group (hereinafter also referred to as polycarboxylic acid) and its salt may be used, but from the viewpoint of suppressing dusting after curing and maintaining low viscosity, polycarboxylic acid and its salt are preferred. preferable.

Polycarboxylic acids are not particularly limited, and include aromatic polycarboxylic acids, aliphatic polycarboxylic acids, and the like.
Examples of aromatic polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, tetrahydroisophthalic acid, hexahydrophthalic acid, hexahydroterephthalic acid, trimellitic acid, and pyromellitic acid.
Aliphatic polycarboxylic acids include adipic acid, sebacic acid, succinic acid, azelaic acid, fumaric acid, maleic acid, and itaconic acid.

Examples of the polycarboxylic acid salts include alkylamine salts of polycarboxylic acids, alkylammonium salts, polycarboxylic acid polyaminoamides, polycarboxylic acid sodium salts, polycarboxylic acid ammonium salts, polycarboxylic acid aminoalcohol salts, and the like. mentioned.

The polycarboxylic acid and its salt may be a polycarboxylic acid copolymer.
Also, the polycarboxylic acid-based copolymer may be a comb-shaped polymer. A comb-shaped polymer indicates a polymer in which three or more side chains are attached to the main chain.
As used herein, the main chain of a polymer means a portion extended by a reaction between polymerizable unsaturated groups. Moreover, the side chain of a polymer means a chain that binds to the main chain of the polymer.

From the viewpoint of suppressing powdering after curing and maintaining low viscosity, polycarboxylic acid copolymerization comprises a structural unit formed from a polycarboxylic acid or a salt thereof and a structural unit formed from a steric repulsive group. preferably included.
By having the above structural unit, the polycarboxylic acid or its salt portion is adsorbed to the thermally conductive filler, and the thermally conductive filler is dispersed by the steric repulsion force and steric repulsion group resulting from the adsorption. It is presumed to be superior in suppressing powder blowing after curing.

Stereorepulsive groups include, for example, polyether chains, polyester chains, polyamide chains, or acrylic resin chains.
Among these, as the steric repulsion group, it is more preferable to have a polyether chain, a polyester chain, or an acrylic resin chain, more preferably to have a polyether chain or an acrylic resin chain. Having an alkyleneoxy group is particularly preferred.
Examples of the polyalkyleneoxy group include -(C ₂ H ₄ O)a- (a: an integer of 2 to 10), -(C ₃ H ₆ O)a- (a: an integer of 2 to 10), and the like. mentioned.

From the viewpoint of suppressing dusting after curing, the structural unit formed from polycarboxylic acid or a salt thereof is preferably a structural unit represented by the following formula (Pc1) or formula (Pc2).

In formula (Pc1), ^RUA represents a hydrogen atom or a methyl group, and M represents a hydrogen atom or a cationic group. Cationic groups include alkali metals such as sodium and calcium, or ammonium.

From the viewpoint of suppressing powdering after curing and maintaining low viscosity, the polycarboxylic acid copolymer has a structural unit formed from a carboxylic acid or a salt thereof and a structural unit formed from a steric repulsive group in the molecular structure. It is preferably a polycarboxylic acid-based copolymer containing and more preferably a polymer having a structure represented by the following formula (Pc3).

In formula (Pc3), R represents a hydrogen atom or a methyl group, M represents a hydrogen atom or an alkali metal, and m and n represent integers of 1-20.

Polycarboxylic acid-based copolymerization further includes structural units other than structural units formed from upper carboxylic acids and salts thereof and structural units formed from steric repulsive groups (hereinafter also referred to as "other structural units"). You can
Styrene etc. are mentioned as another structural unit.

The polycarboxylic acid-based copolymer may be a synthetic product or a commercially available product. Commercially available products include, for example, CRODA's Hypermer (registered trademark) KD-9 (a comb-shaped polymeric ionic dispersant having a polycarboxylic acid as a main skeleton and a hydrocarbon chain as a side chain, weight average molecular weight of 760 , an acid value of 74 mgKOH/g) and the like.

The molecular weight of the anionic dispersant (the weight average molecular weight when it has a molecular weight distribution) is not particularly limited, but is preferably less than 1000, more preferably 50 or more and 800 or less.

From the viewpoint of suppressing powdering after curing and maintaining low viscosity, the content of the anionic dispersant (A) is 0.15% by mass to 0.8% by mass with respect to the total mass of the composition. preferably 0.2% by mass to 0.6% by mass, even more preferably 0.4% by mass to 0.6% by mass.

In addition, from the viewpoint of suppressing powdering after curing and maintaining low viscosity, the ratio of the content of the anionic dispersant (A) to the thermally conductive filler (F) described later (anionic dispersant (A) / Thermally conductive filler (F)) is preferably 0.001 to 0.015, more preferably 0.002 to 0.01, and 0.003 to 0.007 on a mass basis. is more preferred.
The anionic dispersant may be contained singly or in combination of two or more in the composition.

<Monomer (B) having a (meth)acryloyl group>
A curable composition according to the present disclosure comprises a monomer (B) having a (meth)acryloyl group. The (meth)acryloyl group-containing monomer (B) may be a monomer having one (meth)acrylate group in one molecule, or a monomer having two or more (meth)acrylate groups in one molecule. There may be.
The monomer having one (meth)acrylate group in one molecule is not particularly limited, and examples thereof include linear, branched or cyclic alkyl (meth)acrylates, acrylic acid and the like.
From the viewpoint of achieving both heat resistance and flexibility, the monomer having one (meth)acrylate group in one molecule is preferably a linear or branched alkyl (meth)acrylate, represented by the following formula (1) It is further preferable that the compound represented by is included.

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

In formula (1), the alkyl group for R ¹ may be linear or branched. Moreover, the alkyl group may have a substituent.
Examples of substituents include a carboxy group, a hydroxy group, an amino group, an aryl group, and a heterocyclic group, preferably a carboxy group or a hydroxy group, more preferably a hydroxy group.

From the viewpoint of achieving both heat resistance and flexibility, the total carbon number of the alkyl group in R ¹ is preferably 2 to 30, more preferably 5 to 25, even more preferably 10 to 25. , a total carbon number of 12 to 24 is particularly preferred.
Here, the total number of carbon atoms means the total number of carbon atoms including the number of carbon atoms of the substituent when the above alkyl group has a substituent containing a carbon atom.

From the viewpoint of achieving both heat resistance and flexibility, in formula (1), R ¹ is preferably a linear or branched alkyl group or an alkyl group having a total carbon number of 2 to 30 having a substituent. It is more preferably a linear or branched alkyl group having a total carbon number of 2 to 25 or having a hydroxyl group, more preferably a linear or branched unsubstituted alkyl group having 12 to 24 carbon atoms.

Monomers having one (meth)acrylate group in one molecule include, for example, 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 and the like.

R ² is a hydrogen atom or a methyl group, preferably a methyl group.

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.

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 from the viewpoint of achieving both heat resistance and flexibility. A compound having two (meth)acrylate groups in one molecule is more preferable, and a compound represented by the following formula (2) is even more preferable.

In formula (2), R ^B1 represents an alkylene group having 1 to 5 carbon atoms, R ^B2 and R ^B3 each independently represent a hydrogen atom or a methyl group, and n represents an integer of 4 or more.
The alkylene group having 1 to 5 carbon atoms represented by R 1 ^B1 may be linear or branched.
From the viewpoint of flexibility, the alkylene group represented by R 1 ^B1 is preferably a branched alkylene group having 2 to 5 carbon atoms, and a linear or branched alkylene group having 2 to 4 carbon atoms. is more preferred, and a branched-chain alkylene group having 3 or 4 carbon atoms is even more preferred.
R ^B2 and R ^B3 are each independently preferably a methyl group.
n is preferably 4-25, more preferably 4-10, even more preferably 3-8.

From the viewpoint of flexibility and shape stability, in formula (2), R ^B1 is a branched alkylene group having 2 to 5 carbon atoms (more preferably a linear or branched carbon number 2 to 4 alkylene groups, more preferably branched-chain alkylene groups having 3 or 4 carbon atoms), R ^B2 and R ^B3 are methyl groups, and n is 4 to 25 (more preferably 4 ~10, more preferably 3 to 8).

In one embodiment, the monomer (B) having a (meth)acryloyl group is at least one selected from monomers having one (meth)acrylate group in one molecule and a (meth)acrylate group in one molecule. and at least one selected from monomers having two or more of

The content ratio (A:B) between the content A of the monomer having one (meth)acrylate group in one molecule and the content B of the monomer having two or more (meth)acrylate groups in one molecule is 99.5:0.5 to 95:5 is preferred, and 99:1 to 97:3 is more preferred, from the viewpoint of hardness and curing rate of the cured product.

The content of the (meth)acryloyl group-containing monomer (B) is preferably 1% by mass to 10% by mass, preferably 2% by mass to 8% by mass, based on the total mass of the composition. more preferred.
The monomer (B) having a (meth)acryloyl group may be contained singly or in combination of two or more in the composition.

The (meth)acryloyl group-containing monomer (B) is preferably a monomer having a molecular weight of less than 1,000.
As used herein, a monomer means a polymerizable compound having a molecular weight of less than 1,000, and a polymerizable polymer means a polymerizable compound having a weight average molecular weight (Mw) of 1,000 or more.
The concept of "polymerizable polymer" in the present disclosure also includes so-called oligomers.

<Polymerization initiator (D)>
The curable composition according to the present disclosure contains a polymerization initiator (D).
The polymerization initiator (D) is a compound that generates polymerization initiation species such as radicals and cations by the energy of light, heat, or both, and may be appropriately selected from known thermal polymerization initiators, known photopolymerization initiators, and the like. It can be selected and used.
From the viewpoint of the reactivity of the monomer (B) having a (meth)acryloyl group, the polymerization initiator (D) is preferably a radical polymerization initiator, more preferably a peroxide that generates free radicals by heat. Organic peroxides that generate free radicals by are more preferred.

Examples of organic peroxides include isobutyl peroxide, α,α'bis(neodecanoylperoxy)diisopropylbenzene, cumyl peroxyneodecanoate, di-n-propylperoxydicarbonate, di-s-butylperoxide, Oxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl) peroxydicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate , di-2-ethoxyethyl peroxydicarbonate, di(ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanoate, dimethoxybutyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) per oxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1 , 3,3-tetramethylbutylperoxy-2-ethylhexanoate, succinic peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoyl)hexane, 1-cyclohexyl-1-methyl Ethyl peroxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, 4-methylbenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, m-tolunoylbenzoylperoxide oxide, benzoyl peroxide, t-butylperoxyisobutyrate, 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) oxy)cyclohexanone, 2,2-bis(4,4-dibutylperoxycyclohexyl)propane, 1,1-bis(t-butylperoxy)cyclododecane, t-hexylperoxyisopropylmonocarbonate, t-butylperoxy Maleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, 2,5-dimethyl-2,5-di(m-toluoylperoxy) oxy)hexane, t-butylperoxyisopropylmonocarbonate, t-butylperoxy-2-ethylhexylcarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t -butyl peroxyacetate, 2,2-bis(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4,4-bis(t-butylperoxy)valerate, di-t-butyl Peroxyisophthalate, α,α'bis(t-butylperoxy)diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumylper oxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne, diisopropylbenzene hydroperoxide, t-butyltrimethylsilyl peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, benzoyl peroxide, lauroyl peroxide and the like.
Among these, from the viewpoint of reactivity, organic peroxides include benzoyl peroxide, t-butylperoxy-2-ethylhexyl carbonate 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate , and cumene hydroperoxide.

-Content-
The content of the polymerization initiator (D) is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the monomer (B) having a (meth)acryloyl group, and 0.5 parts by mass. It is more preferable that the content is 4 parts by mass or less.

<Thermal conductive filler (F)>
A curable composition according to the present disclosure comprises a thermally conductive filler (F).
The material of the thermally conductive filler (F) is not particularly limited, and examples thereof include zinc oxide, magnesium oxide, aluminum oxide, boron nitride, aluminum nitride, and carbon. It preferably contains at least one selected from zinc oxide, magnesium oxide and aluminum oxide, and more preferably contains zinc oxide, from the viewpoint of high thermal conductivity and excellent insulation.
Zinc oxide, magnesium oxide and aluminum oxide that are applied as thermally conductive fillers are not particularly limited, and zinc oxide that is commonly used as thermally conductive fillers can be mentioned.

The thermally conductive filler (F) may be a surface-treated thermally conductive filler. Containing a surface-treated thermally conductive filler improves the affinity between the thermally conductive filler and other ingredients other than the thermally conductive filler, suppresses powder blowing after curing, and has a low viscosity. It can contribute to improvement of maintenance.

The surface treatment of the thermally conductive filler is not particularly limited, and may be a physical treatment or a chemical treatment, and any known treatment capable of treating the surface of the particles constituting the thermally conductive filler is applied. can do.
The surface treatment is preferably a treatment using a surface treatment agent.

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

From the viewpoint of dispersibility, the thermally conductive filler (F) is preferably surface-treated using a silane-based coupling agent as a surface treatment agent.

The thermally conductive filler (F) may be entirely surface-treated thermally conductive filler, or partially surface-treated thermally conductive filler. From the viewpoints of suppression of powdering after curing, maintenance of low viscosity and high thermal conductivity, it is preferable to contain a surface-treated thermally conductive filler as the thermally conductive filler (F).

The thermally conductive filler (F) preferably has a volume average particle size of 0.05 μm to 30 μm, preferably 0.1 μm to 0.1 μm, from the viewpoints of suppressing dusting after curing, maintaining low viscosity, and thermal conductivity. It is more preferably 20 μm, and even more preferably 0.3 μm to 15 μm.

In addition, a thermally conductive filler (F) having a volume average particle diameter exceeding 30 μm (preferably zinc oxide ) and a thermally conductive filler (F) having a volume average particle size of 0.05 μm to 30 μm (preferably 0.1 μm to 20 μm, more preferably 0.1 μm to 15 μm). more than 50 μm and a thermally conductive filler (F) may be used in combination.

The volume average particle size of the thermally conductive filler is measured by a laser diffraction/scattering method in accordance with JIS Z 8825:2013 (corresponding international standard: ISO13320).
Specifically, a sample containing thermally conductive filler particles is measured for volume distribution of the thermally conductive filler particles using a laser diffraction/scattering particle size analyzer. Based on the obtained measured value (volume distribution), the volume average particle size of the thermally conductive filler contained in the sample can be obtained.
As an example of a measuring device, a laser diffraction/scattering particle size measuring device manufactured by Shimadzu Corporation, product name: nanoparticle size distribution measuring device SALD-7500nano can be used.

In the curable composition according to the present disclosure, two types of thermally conductive fillers (F) (preferably zinc oxide) having different volume average particle sizes are used from the viewpoint of highly filling the composition with the thermally conductive fillers (F). It is preferable to include the above.
When the curable composition according to the present disclosure contains two or more types of thermally conductive fillers (F) (preferably zinc oxide) having different volume average particle sizes, from the above viewpoint, the maximum volume average particle size with respect to the minimum volume average particle size is preferably 1.5 times or more.

In addition, in the curable composition according to the present disclosure, the volume average particle diameter is 0.05 μm to 30 μm because it has excellent thermal conductivity, suppresses powder blowing after curing, and maintains low viscosity. More preferably, the difference in volume average particle size is 5 μm or more and two or more types of zinc oxide having different volume average particle sizes are included.

-Content-
The content of the thermally conductive filler (F) is preferably 80% by mass or more, more preferably 85% to 98% by mass, more preferably 90% to 96% by mass, based on the total mass of the composition. % by mass is more preferred.

The content of the thermally conductive filler (F) other than zinc oxide is preferably 60% by mass or less with respect to the total mass of the composition with respect to the total mass of the thermally conductive filler (F). It is more preferably 40% by mass or less, and even more preferably 0% by mass or more and 20% by mass or less.

<Plasticizer (E)>
The curable composition according to the present disclosure contains a plasticizer (E).
The plasticizer (E) is not particularly limited, and examples thereof include polymers used as plasticizers, fatty acid ester compounds having unsaturated hydrocarbon groups, aromatic carboxylic acid ester compounds, and fatty acids having unsaturated hydrocarbon groups. and oils containing aromatic carboxylic acids.
In the present disclosure, "polymer" means a compound having a weight average molecular weight (Mw) of 1,000 or more.
In the present disclosure, the concept of "polymer" also includes so-called oligomers.

Examples of polymers used as plasticizers include acrylic polymers, polyester polymers, polyurethane polymers, and silicone polymers. From the viewpoint of flexibility, acrylic polymers are preferred.

The acrylic polymer is not particularly limited as long as it has structural units formed from acrylic monomers, and the acrylic polymer may be a homopolymer or a copolymer.
Acrylic monomers include, for example, acrylic acid, acrylic acid esters, acrylonitrile, acrylamide, methylolacrylamide, and the like.

From the viewpoint of maintaining low viscosity and heat resistance, the acrylic polymer preferably contains a structural unit formed from an acrylic acid ester.
Alkyl (meth)acrylates are preferred as (meth)acrylic esters. Meth)acrylic esters include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and isobutyl (meth)acrylate.
Moreover, the alkyl acrylate may be a non-functional alkyl acrylate, or may have a functional group such as a carboxy group or a hydroxy group (hydroxyl group).

The acrylic polymer is preferably a polymer having a structure represented by the following formula (P ^AC ).

In formula (P ^AC ), Rp represents a hydrogen atom or an alkyl group.
In formula (P ^AC ), the alkyl group may have a substituent. A carboxy group, a hydroxyl group, an amino group, etc. are mentioned as a substituent. The substituent is preferably a carboxy group or a hydroxy group, more preferably a hydroxy group.
As the alkyl group, a saturated alkyl group is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.

When the curable composition according to the present disclosure contains a plasticizer (E), and the plasticizer (E) is a polymer, it is preferably a polymer having a glass transition temperature of -20 ° C. or lower, and the glass transition temperature is more preferably -20°C or lower.
The glass transition temperature (Tg) of a polymer is determined by examining the inflection point of the DSC curve measured using a differential thermal analyzer (DSC).

Examples of fatty acid ester compounds having an unsaturated hydrocarbon group include ester compounds such as 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.

When the curable composition according to the present disclosure contains a plasticizer (E), from the viewpoint of maintaining low viscosity and high temperature stability, the plasticizer (E) is an acrylic polymer and an aromatic carboxylic acid ester compound. It preferably contains at least one compound selected from the group consisting of, and more preferably contains at least one compound selected from the group consisting of a polymer having a structure represented by the formula (P ^AC ) and a trimellitate ester. preferable.

-Content-
When the curable composition according to the present disclosure contains a plasticizer (E) (the total amount if two or more are included), from the viewpoint of maintaining low viscosity, heat resistance and flexibility, the plasticizer (E) The content of is preferably 10 parts by mass to 60 parts by mass, more preferably 20 parts by mass to 50 parts by mass, with respect to 100 parts by mass of the monomer (B) having a (meth)acryloyl group, It is more preferably 30 parts by mass to 45 parts by mass.
The plasticizer (E) may be contained singly or in combination of two or more in the composition.

<<Other Additives>>
The curable composition according to the present disclosure optionally includes the anionic dispersant (A), a monomer having a (meth)acryloyl group (B), a polymerization initiator (D), and a thermally conductive filler (F). , and components other than the plasticizer (E) (hereinafter also referred to as “other additives”).
As other additives, additives such as other dispersants, reducing agents (G), antioxidants, corrosion inhibitors, rust inhibitors, rheology control agents (viscosity modifiers), etc. can be appropriately blended.
The above additives may be used singly or in combination of two or more.
<<Reducing agent (G)>>
The curable composition according to the present disclosure may further contain a reducing agent (G), if necessary. When the curable composition according to the present disclosure is applied to a two-component curable composition described later, it is preferable that one curable composition contains the reducing agent (G).
By adding the reducing agent (G), the decomposition of the polymerization initiator (D) (for example, peroxide) is facilitated, and the polymerization reaction tends to proceed even under low temperature conditions.

The reducing agent (G) is not particularly limited as long as it can promote the decomposition of the polymerization initiator (D), and includes known reducing agents used in combination with the polymerization initiator. From the viewpoint of accelerating the decomposition of , it is preferable to use a metal compound-based reducing agent.

Examples of metal compound reducing agents include stannous oxide, dioctyltin dilaurate, dibutyltin dilaurate, dibutyltin diacetate, zinc naphthenate, antimony trichloride, potassium oleate, sodium O-phenylphenate, bismuth nitrate, chloride ferric iron, tetra-n-butyltin, tetra(2-ethylhexyl) titanate, cobalt 2-ethylhexoate, ferric 2-ethylhexoate and the like.
Among these, cobalt 2-ethylhexoate and cobalt naphthenate are preferable as the metal compound reducing agent from the viewpoint of reactivity.

-Content-
When the curable composition according to the present disclosure contains the reducing agent (G), from the viewpoint of curing speed, the content of the reducing agent (G) is 100 parts by mass of the monomer (B) having the (meth)acryloyl group. On the other hand, it is preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 2 parts by mass or more and 9 parts by mass or less.
The reducing agent (F) may be used singly or in combination of two or more.

<<Other Dispersants>>
The curable composition according to the present disclosure may further contain a dispersant other than the anionic dispersant (A) (hereinafter sometimes referred to as "other dispersant").
Other dispersants are not particularly limited as long as they are dispersants other than the anionic dispersant (A). Examples include cationic surfactants, nonionic surfactants, amphoteric surfactants, polymer surfactants, Active agents, alcohols, metallic soaps, fluorine-based surfactants, boron-based surfactants, and the like are included.

The content of other dispersants is preferably 5% by mass or less, preferably 3% by mass or less, relative to the total mass of the dispersants contained in the curable composition according to the present disclosure. It is more preferably 0% by mass or more and 1% by mass or less, and it is particularly preferable not to contain other dispersants.

<<Antioxidant>>
Examples of antioxidants include phenol antioxidants, amine antioxidants, phosphite antioxidants, and the like.

<<Corrosion Inhibitor>>
Corrosion inhibitors include benzotriazole, tolyltriazole, thiadiazole, benzimidazole, and the like.

<<Antirust agent>>
Examples of rust preventives include metal sulfonate compounds and sorbitan compounds.

<<Rheology control agent>>
In the present disclosure, the rheology control agent refers to an agent that imparts non-Newtonian properties to shear rate changes, such that the shear viscosity increases in the low shear rate range and decreases in the high shear rate range. It is an additive that imparts flow properties.

The rheology control agent may be an inorganic compound rheology control agent or an organic compound rheology control agent. Inorganic system rheology control agents include fumed silica, bentonite, mica, kaolin, and the like.
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, the rheology control agent is preferably an inorganic compound rheology control agent, more preferably fumed silica or bentonite, and still more preferably bentonite. When fumed silica is used, it is preferable to make the surface hydrophobic with a silane coupling agent or other surface modifier. When bentonite is used, organically modified bentonite organically modified with a quaternary ammonium salt or other organic modifier is preferably used.

The content of the rheology control agent is not particularly limited and can be set as appropriate.

[Physical properties of curable composition]
The spreading consistency of the curable composition according to the present disclosure is preferably 100 to 500, more preferably 260 to 340, and 280 to 310, from the viewpoint of viscoelasticity, handleability and defoaming properties. is more preferable.
Spreading penetration was measured by inserting 0.05 mL of the sample (curable composition before curing) between two acrylic plates in an environment of 25 ° C., applying a load of 100 g on the plate for 5 seconds, and removing the sample. It is determined by compressing, measuring the spread diameter millimeters of the sample, subtracting 1 from this measurement, and multiplying by 20.
Spread consistency = (measured value - 1) x 20

[Form of curable composition]
The curable composition according to the present disclosure is preferably a one-component curable composition that uses one type of curable composition when applied to a substrate, a heating element, or the like. The curable composition according to the present disclosure may be a two-component curable composition that uses a mixture of two curable compositions.

[Method for producing curable composition]
The method for producing the curable composition according to the present disclosure is not particularly limited and is not particularly limited. A curable composition according to the present disclosure can be produced, for example, by the following method.
An anionic dispersant (A), a monomer having a (meth)acryloyl group (B), a polymerization initiator (D), a plasticizer (E) and a thermally conductive filler (F), if necessary other additives , is obtained by putting into a stirring vessel and stirring and mixing.
In addition, a well-known stirrer etc. can be used for stirring and mixing.

In the method for producing a curable composition, when adding other additives, the additives may be stirred only for a time during which the additives can be dissolved or dispersed, and the anionic dispersant (A) has a (meth)acryloyl group. It may be added to the stirring vessel together with the monomer (B), the polymerization initiator (D), the plasticizer (E) and the thermally conductive filler (F), or may be added after mixing the components other than the other additives. good.

(cured product)
A cured product according to the present disclosure is a cured product of the curable composition according to the present disclosure. The method for curing the curable composition is not limited and can be appropriately selected from commonly used methods. Examples of the curing method include irradiation with an active energy ray and heating, and a curing method by heating is preferred.
When curing by heating, the heating temperature is preferably 60° C. or higher, more preferably 70° C. or higher. Further, the heating time is preferably 1 minute to 120 minutes.
Moreover, the curable composition may be cured by reaction with moisture in the air, or may be cured at room temperature.

The thermal conductivity of the cured product according to the present disclosure is 0.5 (W m / K) to 50 (W m / K), preferably 1 (W m / K) to 20 (W m / K), and 3 (W m / K) to 20 (W m / K) It is more preferable to have
The softness of the cured product according to the present disclosure is preferably 100 or less, more preferably 85 or less in Shore OO, from the viewpoint of stress relaxation to peripheral parts of the cured product.
Similarly, the Asker C hardness is preferably 100 or less, more preferably 85 or less, and even more preferably 75 or less.
The softness of the cured product according to the present disclosure is determined according to ASTM D2240 and Asker C according to JIS K 7312 (1996).

<Application>
The curable composition according to the present disclosure can be suitably used, for example, as a TIM that fills a recess (a gap between a heating element and a radiator) formed in a substrate.
Since the curable composition according to the present disclosure is excellent in suppressing dusting after curing, it is possible to maintain the desired quality for a long period of time. In addition, since the curable composition according to the present disclosure has low viscosity and excellent thermal conductivity, the resulting cured product has excellent manufacturability and thermal conductivity.
The cured product obtained from the curable composition according to the present disclosure has excellent flexibility, shape stability, and thermal conductivity, and therefore has excellent followability to the coating surface such as recesses formed on the substrate. Even if there are parts with different heights on the board, the heat can be released efficiently. In addition, since the curable composition according to the present disclosure can follow the microscopic unevenness of the material on the substrate, heat can be released efficiently, and the followability to the coated surface due to temperature fluctuations is also excellent. From the point of view, it can be suitably applied as a gap filler.

EXAMPLES Hereinafter, the curable composition and cured product according to the present disclosure will be specifically described with reference to examples. The curable composition and cured product according to the present disclosure are not limited by these examples.

(Examples 1 to 10 and Comparative Examples 1 to 9)
Each raw material was blended in the amounts shown in Tables 1 and 2, and a rotation/revolution mixer (manufactured by Thinky Co., Ltd., product name: Awatori Mixer ARV-310) was used at 2,000 rpm (revolutions per minute). , 2 minutes at atmospheric pressure to prepare a curable composition.

(Example 11)
Each raw material of liquid A and liquid B was blended in the amount shown in Table 1, and was mixed at 2,000 rpm and 2 minutes, and mixed under atmospheric pressure to obtain liquids A and B. After that, A liquid and B liquid are blended at a mass ratio of 1: 1, using a rotation / revolution mixer (manufactured by Thinky Co., Ltd., product name: Awatori Mixer ARV-310), 2,000 rpm, 1 minute, A two-part curable composition was prepared by mixing under atmospheric pressure.

Using the curable compositions prepared in Examples 1 to 11 and Comparative Examples 1 to 9, the following evaluations were performed. The results are shown in Tables 1 and 2.

-evaluation-
<Viscosity (maintaining low viscosity)>
The curable composition prepared above was measured for shear viscosity η [Pa·s] at 25° C. using a dynamic viscoelasticity measuring device (manufactured by Anton Paar, product name: MCR 101).
A PP25 parallel plate (25 mm in diameter, manufactured by Anton Paar) was used as a jig for the curable composition to be measured.
The measurement is shear viscosity at each shear rate of 0.01 [1/s], 0.1 [1/s], 1 [1/s], 10 [1/s] and 100 [1/s] It was carried out by measuring η [Pa·s].
When the shear viscosity η [Pa s] at 25° C. measured at a shear rate of 0.1 [1/s] is 100 [Pa s] or less, it can be said to be excellent in maintaining low viscosity. .

<Blowing powder>
The curable composition prepared above is cured at 80° C. for 30 minutes in a N ₂ purge atmosphere so that the size of the cured product is 30 mm × 10 mm × 6 mm in length × width × height (thickness). Molded.
A repeated bending test was performed on the molded cured product. Hold the end of the cured product in the vertical direction, bend this end up and down at an angle of 5 degrees or more with respect to the vertical direction of the cured product, and then return the end to its original state. After 100 reciprocating motions, the mass of the component peeled off from the cured product was measured, and suppression of powder blowing after curing was evaluated based on the following evaluation criteria.
When the powder blowing evaluation is A, it can be said that the powder blowing after curing is excellently suppressed.
-Evaluation criteria-
A: Powder blowing is not seen.
B: The mass of powdered components is within 0.05% by mass of the total mass.
C: The mass of the dusting component is 0.05% by mass or more of the total mass.

<Thermal conductivity (W / (m K)>
Thermal conductivity was measured according to ASTM D5470.
A curable composition molded so that the length x width x height (thickness) is 10 mm x 10 mm x 1.0 mm is sandwiched between copper plates of 10 mm x 10 mm, and placed at 80 ° C. for 30 minutes in a N ₂ purge atmosphere. After curing under the curing conditions of , the thermal resistance ⁽ unit: K cm / W) was measured with a thermal resistance measuring device (manufactured by Tsukubarika Seiki Co., Ltd., product name: thermal resistance measuring device), and the thermal conductivity converted to

<spread consistency>
Spreading penetration is measured by inserting 0.05 mL of the sample (curable composition before curing) between two acrylic plates in an environment of 25 ° C., applying a load of 100 g on the plate for 5 seconds, and removing the sample. Compress and measure the spread diameter millimeters of the sample, subtract 1 from this measurement and multiply by 20 to obtain.

<Hardness: shape stability>
-Softness after curing: Shore OO hardness (sample thickness: 6 mm)-
The softness of the cured product of the curable composition was measured according to ASTM D2240.
The curable composition was molded to 50 mm × 20 mm × 6 mm (thickness 6 mm), cured under N ₂ purge atmosphere at 80 ° C. for 30 minutes, and then measured with a durometer (product name: GS-754G, Teclock Co., Ltd.). (manufactured) was used to measure the Shore OO hardness.

-Softness after curing: Asker C hardness (sample thickness: 6 mm)-
The softness of the cured product of the curable composition was measured according to JIS K 7312 (1996).
The curable composition was molded to a size of 50 mm × 20 mm × 6 mm (thickness 6 mm), cured at 80 ° C. for 30 minutes in a N ₂ purge atmosphere, and then tested with an Asker rubber hardness tester type C (manufactured by Kobunshi Keiki Co., Ltd.). ) was used to measure the Asker C hardness.

Details of each component described in Tables 1 and 2 are as follows. "-" in Tables 1 and 2 indicates that the corresponding component is not included.
In Tables 1 and 2, "filling rate mass [%]" represents the mass ratio of the total mass of the thermally conductive filler (F) to the total mass of the composition.
In Tables 1 and 2, dispersant/filler represents the weight ratio of the anionic dispersant (A) to the total weight of the thermally conductive filler (F).

<<monomer (B) having a (meth)acryloyl group>>
· Light ester L: lauryl methacrylate; manufactured by Kyoeisha Chemical Co., Ltd., product name: LMA
· HO-250 (N): 2-hydroxyethyl methacrylate; manufactured by Kyoeisha Chemical Co., Ltd., product name; HO-250 (N)
・ITEC: 2-decyltetradecyl methacrylate; manufactured by Shin-Nakamura Chemical Co., Ltd. ・9PG (bifunctional monomer): Polypropylene glycol dimethacrylate; manufactured by Shin-Nakamura Chemical Co., Ltd., product name: 9PG

<<Plasticizer (E)>>
・ARUFON UP-1020 (product name); acrylic polymer; manufactured by Toagosei Co., Ltd.; weight average molecular weight; 2,000; glass transition temperature (Tg); -80°C
・ ADEKA CIZER C-880 (product name); mixed linear alkyl trimellitate; manufactured by ADEKA Co., Ltd.,

<<polymerization initiator (C)>>
Kayakumen H: cumene hydroperoxide; manufactured by Kayaku Akzo Co., Ltd. Perocta O: 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate; manufactured by NOF Corporation

<<Reducing agent (G)>>
・ Cobalt hexoate; manufactured by Toei Kako Co., Ltd.

<<Anionic dispersant (A)>>
· Crodafos O3A: oxyethylene oleyl ether phosphate (anionic dispersant), OH value: 130 mgKOH / g, molecular weight: 420, manufactured by CRODA · Hypermer KD9: comb-shaped polycarboxylic acid (anionic dispersant), weight average Molecular weight 760, OH value 66 mgKOH/g to 77 mgKOH/g, Hypermer KD3 manufactured by CRODA: comb-shaped polyamine (weak cationic polymer), weight average molecular weight: 2,000 to 30,000, OH value: 16 mgKOH/g to 25 mg KOH / g, CRODA Hypermer KD4: comb-shaped polycarboxylic acid (weak anionic polymer), weight average molecular weight 1,700, OH value: 28 mg KOH / g, CRODA Hypermer KD16: dicarboxylic acid, weak anionic Compound, manufactured by CRODA, molecular weight: 490, OH value: 299 mgKOH/g, manufactured by CRODA ・Hypermer KD57: dicarboxylic acid, weak anionic compound, manufactured by CRODA, molecular weight: 470, OH value: 489 mgKOH/g, manufactured by CRODA - Oleic acid (9-octadecenoic acid); molecular weight: 282, OH value: 198 mgKOH/g to 204 mgKOH/g, manufactured by NOF Corporation - NIKKOL (registered trademark) selachyl alcohol (product name); monooleyl glyceryl ether, Molecular weight: 342, OH value: 295 mgKOH/g to 335 mgKOH/g, manufactured by Nippon Surfactant Industry Co., Ltd.

<<Other Additives>>
・Viscosity modifier (rheology control agent): CLAYTONE-40: manufactured by BYK

<<Thermal conductive filler (F)>>
・Zinc oxide type 1; Volume average diameter D50; 0.6 μm, manufactured by Sakai Chemical Industry Co., Ltd. ・Baked zinc white; Volume average diameter D50; Coupling agent treatment, volume average particle size: 12 μm, manufactured by Hakusui Tech Co., Ltd.

As shown in the results of Tables 1 and 2, the cured products formed from the curable compositions of Examples 1 to 11 are compared to the cured products formed from the curable compositions of Comparative Examples 1 to 9. , It can be seen that it is excellent in suppressing powder blowing after curing and maintaining low viscosity. As described above, the curable composition and cured product according to the present disclosure can be suitably used as a gap filler.

Claims (11)

an anionic dispersant (A) having an OH value of 40 mgKOH to 160 mgKOH/g;
(Meth) a monomer (B) having an acryloyl group;
a polymerization initiator (D);
a plasticizer (E);
a thermally conductive filler (F);
including
A curable composition in which the content of the anionic dispersant (A) is 0.1% by mass to 1.0% by mass relative to the total mass of the composition. The curable composition according to claim 1, wherein the monomer (B) contains a compound represented by the following formula (1).

In formula (1), R ¹ represents an alkyl group having 1 to 50 carbon atoms, and R ² represents a hydrogen atom or a methyl group. The curable composition according to claim 1 or 2, wherein the monomer (B) contains a compound represented by the following formula (2).

In formula (2), R ^B1 represents an alkylene group having 1 to 5 carbon atoms, R ^B2 and R ^B3 each independently represent a hydrogen atom or a methyl group, and n represents an integer of 4 or more. The curable composition according to any one of claims 1 to 3, wherein the anionic dispersant (A) comprises acid groups and salts thereof. 5. The curable composition according to claim 4, wherein said acid group is a carboxy group or a phosphate group. The curable composition according to any one of claims 1 to 5, wherein the anionic dispersant (A) has a molecular weight of less than 1,000. The curable composition according to any one of claims 1 to 6, wherein the plasticizer (F) comprises an acrylic polymer or a trimellitate ester. The content ratio of the anionic dispersant (A) to the thermally conductive filler (F) (anionic dispersant (A)/thermally conductive filler (F)) is 0.001 to 0.001 on a mass basis. 015, the curable composition according to any one of claims 1 to 7. A curable composition according to any preceding claim, wherein the thermally conductive filler (F) comprises zinc oxide. The curable composition according to any one of claims 1 to 9, wherein the content of the thermally conductive filler (F) is 70% by mass to 98% by mass with respect to the total mass of the composition. thing. A cured product of the curable composition according to any one of claims 1 to 10.