Thermally conductive resin composition, cured product

Abstract

The purpose of the present invention is to provide a thermally conductive resin composition which enables the achievement of a cured product that exhibits excellent tensile strength and excellent elongation, while maintaining adequate thermal conductivity. The present invention provides a thermally conductive resin composition which contains the components (A) to (E) described below. Component (A): a urethane (meth)acrylate which has a polyether skeleton, while having a (meth)acryloyl group at one end Component (B): a monofunctional (meth)acrylic monomer which has a polyether skeleton, but does not have a urethane skeleton Component (C): a radical polymerization initiator Component (D): a plasticizer Component (E): a thermally conductive powder

Description

Technical Field

[0001] The present invention relates to a thermally conductive resin composition and a cured product.

Background Art

[0002] In recent years, for the purpose of dissipating heat generated from electrical and electronic components to the outside, a thermally conductive resin composition is used between a heat generating body of an electrical and electronic component such as a semiconductor and a heat dissipating member such as a heat dissipating fin. As the thermally conductive resin composition, a thermally conductive resin composition is frequently used because it can achieve both adhesiveness and thermal conductivity.

[0003] Japanese Patent Application Laid-Open No. 2015-212325 discloses a thermally conductive resin composition containing a polyurethane having a (meth)acryloyl group and a polyoxyalkylene skeleton, a polymerizable monomer containing (meth)acrylic acid, a thermally conductive filler, and a polymerization initiator.

Summary of the Invention

[0004] However, the thermally conductive resin composition as disclosed in Japanese Patent Application Laid-Open No. 2015-212325 adds a large amount of a thermally conductive filler to obtain thermal conductivity, so that the cured product becomes hard and brittle. Therefore, there is a problem that it is difficult to follow the members such as electrical and electronic components.

[0005] Therefore, the present invention has been made in view of the above situation, and an object thereof is to provide a thermally conductive resin composition capable of obtaining a cured product excellent in tensile strength and extensibility while maintaining thermal conductivity.

[0006] The gist of the present invention will be described below. [1] A thermally conductive resin composition containing the following components (A) to (E). Component (A): A urethane (meth)acrylate having a polyether skeleton and having a (meth)acryloyl group at one end Component (B): A monofunctional (meth)acrylic monomer having a polyether skeleton and not having a urethane skeleton Component (C): A radical polymerization initiator (D) Component: Plasticizer (E) Component: Thermally conductive powder. [2] A thermally conductive resin composition comprising the following agents A and B. Agent A: A composition containing the following components (A) to (E). (A) Component: Polyether backbone urethane (meth)acrylate having a (meth)acryloyl group at one end. (B) Component: Monofunctional (meth)acrylic monomer having a polyether backbone and not a urethane backbone (C) Component: Radical polymerization initiator (D) Component: Plasticizer (E) Component: Thermally conductive powder Agent B: A composition containing at least a curing accelerator. [3] The thermally conductive resin composition according to [1] or [2], wherein the amount of component (A) added (blended amount) is in the range of 20 to 90 parts by mass with respect to 100 parts by mass of the total of component (A) and component (B). [4] The thermally conductive resin composition according to any one of [1] to [3], wherein the amount of component (D) added (blended amount) is in the range of 10 to 200 parts by mass with respect to 100 parts by mass of the total of component (A) and component (B). [5] The thermally conductive resin composition according to any one of [1] to [4], wherein the component (D) is a polyether-based plasticizer. [6] The above (E) component is, (E1) Thermally conductive powder with an average particle size of 0.01 μm or more and less than 2.0 μm, (E2) Thermally conductive powder with an average particle size of 2.0 μm or more and less than 20 μm, (E3) A thermally conductive resin composition according to any one of items [1] to [5], comprising a thermally conductive powder with an average particle size of 20 μm or more and less than 150 μm. [7] The thermally conductive resin composition according to [6], wherein the mass ratio of (E1) / (E3) of component (E) is 0.08 to 1.00 and the mass ratio of (E2) / (E3) is 0.15 to 1.50. [8] A thermally conductive resin composition according to any one of [1] to [7], wherein the elongation of the cured product is 60 to 1500%. A cured product obtained from a thermally conductive resin composition described in any one of items [9][1] to [8]. An electronic component characterized by dissipating heat using a thermally conductive resin composition described in any one of items

[10] [1] to [8].

[11] A thermally conductive resin composition comprising the following components (A"), (B"), (C), and (E), wherein the tensile strength of the cured product is 0.40 MPa or higher and the elongation of the cured product is 60 to 1500%. (A) Component: Urethane (meth)acrylate (B) Component: Monofunctional (meth)acrylic monomer without a urethane skeleton (C) Component: Radical polymerization initiator (E) Component: Thermally conductive powder.

[12] The thermally conductive resin composition according to

[11] , wherein the amount of component (A) added (amount blended) is in the range of 20 to 90 parts by mass with respect to 100 parts by mass of the total of component (A) and component (B).

[13] The thermally conductive resin composition according to

[11] or

[12] , further comprising component (D) below. (D) Ingredient: Plasticizer.

[14] The thermally conductive resin composition according to

[13] , wherein the amount of component (D) added (blended amount) is in the range of 10 to 200 parts by mass with respect to 100 parts by mass of the total of component (A) and component (B).

[15] The thermally conductive resin composition according to

[13] or

[14] , wherein the component (D) is a polyether-based plasticizer.

[16] The above (E) component is, (E1) Thermally conductive powder with an average particle size of 0.01 μm or more and less than 2.0 μm, (E2) Thermally conductive powder with an average particle size of 2.0 μm or more and less than 20 μm, (E3) A thermally conductive resin composition according to any one of items

[11] to

[15] , comprising a thermally conductive powder with an average particle size of 20 μm or more and less than 150 μm.

[17] The thermally conductive resin composition according to

[16] , wherein the mass ratio of (E1) / (E3) of component (E) is 0.08 to 1.00 and the mass ratio of (E2) / (E3) is 0.15 to 1.50. A cured product obtained from the thermally conductive resin composition according to any one of

[18] and

[11] to

[17] .

[19] An electronic component characterized by dissipating heat with the thermally conductive resin composition according to any one of

[11] to

[17] .

Mode for Carrying Out the Invention

[0007] According to the first aspect of the present invention, a thermally conductive resin composition containing the following components (A) to (E) is provided: Component (A): A urethane (meth) acrylate having a polyether backbone and having a (meth) acryloyl group at one end Component (B): A monofunctional (meth) acrylic monomer having a polyether backbone and no urethane backbone Component (C): A radical polymerization initiator Component (D): A plasticizer Component (E): A thermally conductive powder.

[0008] According to the second aspect of the present invention, a thermally conductive resin composition containing the following Agent A and Agent B is provided: Agent A: A composition containing the following components (A) to (E). Component (A): A urethane (meth) acrylate having a polyether backbone and having a (meth) acryloyl group at one end Component (B): A monofunctional (meth) acrylic monomer having a polyether backbone and no urethane backbone Component (C): A radical polymerization initiator Component (D): A plasticizer Component (E): A thermally conductive powder Agent B: A composition containing at least a curing accelerator.

[0009] According to the third aspect of the present invention, a thermally conductive resin composition containing the following components (A"), (B"), (C) and (E), having a tensile strength of the cured product of 0.40 MPa or more and an elongation rate of the cured product of 60 to 1500% is provided: Component (A"): Urethane (meth) acrylate Component (B"): A monofunctional (meth) acrylic monomer having no urethane backbone (C) component: Radical polymerization initiator (E) component: Thermally conductive powder

[0010] According to the present invention, there can be provided a thermally conductive resin composition capable of obtaining a cured product that maintains thermal conductivity and is excellent in tensile strength and extensibility.

[0011] The details of the invention will be described below. The present invention is not limited only to the following and can be variously modified within the scope of the claims. Throughout this specification, singular expressions should be understood to include the concept of their plural forms unless otherwise specifically stated. Therefore, singular articles (for example, in English, "a", "an", "the", etc.) should be understood to include the concept of their plural forms unless otherwise specifically stated. Also, the terms used in this specification should be understood to be used in the meaning usually used in the art unless otherwise specifically stated. Therefore, unless otherwise defined, all technical terms and scientific and technical terms used in this specification have the same meaning as generally understood by those skilled in the art to which the present invention pertains. In case of contradiction, this specification (including definitions) shall prevail.

[0012] In this specification, "X to Y" is used in the sense of including the numerical values (X and Y) described before and after it as the lower limit value and the upper limit value, and means "X or more and Y or less". Also, in the present invention, (meth)acrylate means both acrylate and methacrylate.

[0013] <Thermally conductive resin composition (first aspect)> <(A) component> Component (A) in the thermally conductive resin composition of the present invention is a polyether-based urethane (meth)acrylate having a (meth)acryloyl group at one end. Here, "component (A) is a polyether-based urethane (meth)acrylate having a (meth)acryloyl group at one end" means that component (A) has a (meth)acryloyl group at only one end, that is, component (A) is a polyether-based urethane (meth)acrylate having a (meth)acryloyl group at one end but not at the other end. For this reason, polyether-based urethane (meth)acrylate having (meth)acryloyl groups at both ends is not included in component (A). Component (A) is not particularly limited as long as it is a polyether-based urethane (meth)acrylate having a (meth)acryloyl group at one end, but by combining it with the other components of the present invention, a cured product with excellent tensile strength and elongation can be obtained while maintaining thermal conductivity. The urethane (meth)acrylate is a compound having a urethane bond formed by reacting an isocyanate group with a hydroxyl group and a (meth)acryloyl group. The polyether skeleton refers to a skeleton having an alkylene oxide, such as polyethylene oxide, polypropylene oxide, or polybutylene glycol.

[0014] The method for producing component (A) is not particularly limited, but examples include urethane (meth)acrylate consisting of a reaction product of a polyol compound having a hydroxyl group and a (meth)acrylate having an isocyanate group, and urethane (meth)acrylate consisting of a reaction product of a polyol compound having a hydroxyl group, a polyisocyanate compound and a (meth)acrylate having a hydroxyl group. The polyol compound having a hydroxyl group is, for example, polyethylene oxide, polypropylene oxide, and polybutylene glycol, and the number of alkylene oxide repeats is not particularly limited, but is, for example, 3 to 500, more preferably 5 to 100, and particularly preferably in the range of 10 to 50. Examples of the (meth)acrylate having an isocyanate group include 2-isocyanatoethyl (meth)acrylate and 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate. The polyisocyanate compound is not particularly limited, but examples include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. Among these, aliphatic polyisocyanates and alicyclic polyisocyanates are preferred from the viewpoint of obtaining a flexible cured product. These may be used individually or in combination.

[0015] Aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-disocyanate, and triphenylmethane triisocyanate. Alicyclic polyisocyanates include isophorone diisocyanate, bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate. Aliphatic polyisocyanates include hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. Examples of the hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 1,6-hexanediol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, (poly)ethylene glycol mono(meth)acrylate, (poly)propylene glycol mono(meth)acrylate, and pentaerythritol tri(meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxycyclohexyl (meth)acrylate are preferred from the viewpoint of obtaining a cured product with excellent flexibility. These may be used individually or in combination.

[0016] Furthermore, examples of catalysts used in the synthesis of component (A) include lead oleate, antimony trichloride, triphenylaluminum, trioctylaluminum, tetrabutyltin, dibutyltin dilaurate, copper naphthenate, zinc naphthenate, zinc octoate, zinc octnate, zirconium naphthenate, cobalt naphthenate, tetra-n-butyl-1,3-diacetyloxydistanoxane, triethylamine, 1,4-diaza[2,2,2]bicyclooctane, and N-ethylmorpholine. Among these, dibutyltin dilaurate, zinc naphthenate, zinc octoate, and zinc octnate are preferred because they yield a heat-conductive resin composition with excellent tensile strength and elongation. It is preferable to use 0.0001 to 10 parts by mass of these catalysts per 100 parts by mass of the total amount of reactants. The reaction temperature is usually 10 to 100°C, and particularly preferably 30 to 90°C. Furthermore, a monofunctional urethane (meth)acrylate can be obtained by sealing the excess isocyanate groups from the synthesis of component (A) using a capping agent. Examples of capping agents include methanol, ethanol, isopropanol, n-propanol, 1-butanol, 1-heptanol, 1-hexanol, and n-octyl alcohol.

[0017] In the present invention, there are no particular restrictions on the weight-average molecular weight of component (A). However, in order to obtain a thermally conductive resin composition that yields a cured product with excellent tensile strength and elongation, the weight-average molecular weight is preferably, for example, 0.3 million to 200,000, more preferably 0.5 million to 100,000, and particularly preferably 10,000 to 50,000. Unless otherwise specified, the weight-average molecular weight was calculated using the standard polystyrene conversion method with size exclusion chromatography (SEC).

[0018] The commercially available products of component (A) mentioned above are not particularly limited, but can be obtained from companies such as Rahn AG and Negami Kogyo Co., Ltd. Specifically, examples include GENOMER 4188, 4312, 4316, and 4590 manufactured by Rahn AG.

[0019] The amount of component (A) added (blended amount) is preferably in the range of 20 to 90 parts by mass, more preferably 25 to 80 parts by mass, even more preferably 30 to 75 parts by mass, even more preferably 40 to 70 parts by mass, and particularly preferably more than 45 parts by mass and less than 65 parts by mass, relative to 100 parts by mass of the total of component (A) and component (B) described later. Within the above range, a thermally conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity even more. If the thermally conductive resin composition contains two or more types of component (A), the amount of component (A) added (blended amount) is the total amount of component (A) relative to 100 parts by mass of the total of component (A) and component (B).

[0020] Alternatively, the amount of component (A) added (blended) is preferably in the range of 3 to 15 parts by mass, more preferably 5.0 to 9.0 parts by mass, and particularly preferably greater than 5.0 parts by mass and 8.5 parts by mass or less, per 100 parts by mass of the total thermal conductive resin composition. Within the above range, a thermal conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity. If the thermal conductive resin composition contains two or more types of component (A), the amount of component (A) added (blended) is the total amount of component (A) per 100 parts by mass of the total thermal conductive resin composition.

[0021] <(B) component> Component (B) in the thermally conductive resin composition of the present invention is a monofunctional (meth)acrylic monomer having a polyether skeleton and not having a urethane skeleton. While there are no particular limitations on the monofunctional (meth)acrylic monomer having a polyether skeleton and not having a urethane skeleton, as long as it is component (B) in the thermally conductive resin composition of the present invention, by combining it with other components of the present invention, a cured product with excellent tensile strength and elongation properties can be obtained while maintaining thermal conductivity. The polyether skeleton refers to a skeleton having alkylene oxides such as polyethylene oxide, polypropylene oxide, or polybutylene glycol. From the viewpoint of obtaining a thermally conductive resin composition that further maintains thermal conductivity while yielding a cured product with excellent tensile strength and elongation (especially elongation), it is preferable that the polyether skeleton in component (B) is a skeleton having polyethylene oxide. The number of repeating alkylene oxide moieties is not particularly limited, but for example, it is 2 to 300. From the viewpoint of obtaining a thermally conductive resin composition that further maintains thermal conductivity while yielding a cured product with excellent tensile strength and extensibility (especially extensibility), it is preferably 2 to 9, and more preferably 5 to 9. A monofunctional (meth)acrylic monomer refers to a compound that has only one (meth)acryloyl group in one molecule.

[0022] The aforementioned component (B) is not particularly limited, but examples include methoxydiethylene glycol mono(meth)acrylate, methoxytriethylene glycol mono(meth)acrylate, methoxytetraethylene glycol mono(meth)acrylate, methoxypentaethylene glycol mono(meth)acrylate, methoxyhexaethylene glycol mono(meth)acrylate, methoxyheptaethylene glycol mono(meth)acrylate, methoxyoctaethylene glycol mono(meth)acrylate, methoxynononaethylene glycol mono(meth)acrylate, methoxydecaethylene glycol mono(meth)acrylate, methoxytripropylene glycol mono(meth)acrylate, methoxytetrapropylene glycol mono(meth)acrylate, methoxypentapropylene glycol mono(meth)acrylate, methoxyhexapropylene glycol mono(meth)acrylate, methoxyheptapropylene glycol mono(meth)acrylate, methoxyoctapropylene glycol mono(meth)acrylate, and methoxynononapropylene glycol mono(meth)acrylate. Methoxydecapropylene glycol mono(meth)acrylate, methoxytributylene glycol mono(meth)acrylate, methoxytetrabutylene glycol mono(meth)acrylate, methoxypentabutylene glycol mono(meth)acrylate, methoxyhexabutylene glycol mono(meth)acrylate, methoxyheptabutylene glycol mono(meth)acrylate, methoxyoctabutylene glycol mono(meth)acrylate, methoxynonabutylene glycol mono(meth)acrylate, methoxydecabutylene glycol Ethoxydiethylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, ethoxytetraethylene glycol mono(meth)acrylate, ethoxypentaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate, ethoxyheptaethylene glycol mono(meth)acrylate, ethoxyoctaethylene glycol mono(meth)acrylate, ethoxynonaethylene glycol mono(meth)acrylate,Ethoxydecaethylene glycol mono(meth)acrylate, ethoxytripropylene glycol mono(meth)acrylate, ethoxytetrapropylene glycol mono(meth)acrylate, ethoxypentapropylene glycol mono(meth)acrylate, ethoxyhexapropylene glycol mono(meth)acrylate, ethoxyheptapropylene glycol mono(meth)acrylate, ethoxyoctapropylene glycol mono(meth)acrylate, ethoxynonapropylene glycol mono(meth)acrylate, ethoxydecapropylene glycol Examples include mono(meth)acrylate, ethoxytributylene glycol mono(meth)acrylate, ethoxytetrabutylene glycol mono(meth)acrylate, ethoxypentabutylene glycol mono(meth)acrylate, ethoxyhexabutylene glycol mono(meth)acrylate, ethoxyheptabutylene glycol mono(meth)acrylate, ethoxyoctabutylene glycol mono(meth)acrylate, ethoxynonabutylene glycol mono(meth)acrylate, and ethoxydecabutylene glycol mono(meth)acrylate. From the viewpoint of obtaining a heat-conductive resin composition that yields a cured product with even better tensile strength and extensibility (especially extensibility) while maintaining thermal conductivity, component (B) is methoxydiethylene glycol mono(meth)acrylate, methoxytriethylene glycol mono(meth)acrylate, methoxytetraethylene glycol mono(meth)acrylate, methoxypentaethylene glycol mono(meth)acrylate, methoxyhexaethylene glycol mono(meth)acrylate, methoxyheptaethylene glycol mono(meth)acrylate, methoxyoctaethylene glycol mono(meth)acrylate, methoxynonaethylene glycol mono(meth)acrylate, ethoxydiethylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, ethoxytetraethylene glycol mono(meth)acrylate, ethoxypentaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate, ethoxyheptaethylene glycol mono(meth)acrylate,Ethoxyoctaethylene glycol mono(meth)acrylate and ethoxynonaethylene glycol mono(meth)acrylate are preferred, methoxydiethylene glycol mono(meth)acrylate, methoxytriethylene glycol mono(meth)acrylate, methoxytetraethylene glycol mono(meth)acrylate, methoxypentaethylene glycol mono(meth)acrylate, ethoxydiethylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, ethoxytetraethylene glycol mono(meth)acrylate, and ethoxypentaethylene glycol mono(meth)acrylate are more preferred, methoxynonaethylene glycol mono(meth)acrylate and ethoxydiethylene glycol mono(meth)acrylate are even more preferred, and ethoxydiethylene glycol mono(meth)acrylate is particularly preferred. These may be used individually or in combination.

[0023] The amount of component (B) added (blended amount) is preferably the mixing ratio with component (A) as specified for component (A) above. Within the above range, a thermally conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity. If the thermally conductive resin composition contains two or more types of component (B), the amount of component (B) added (blended amount) is the total amount of component (B) per 100 parts by mass of the total of component (A) and component (B).

[0024] Alternatively, the amount of component (B) added (blended) is preferably in the range of 1 to 10 parts by mass, more preferably 3.0 parts by mass or more and less than 6.5 parts by mass, and particularly preferably 4.0 parts by mass or more and 6.0 parts by mass or less, per 100 parts by mass of the total thermal conductive resin composition. Within the above range, a thermal conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity even more. If the thermal conductive resin composition contains two or more types of component (B), the amount of component (B) added (blended) is the total amount of component (B) per 100 parts by mass of the total thermal conductive resin composition.

[0025] <(C) component> The component (C) that can be used in the present invention is a radical polymerization initiator. Examples of such a component (C) include photoradical polymerization initiators (hereinafter also referred to as photoradical initiators) and organic peroxides. The curing mode of the thermally conductive resin composition of the present invention can be selected from photocuring, heat curing, or redox curing by selecting component (C) of the present invention. For example, if you want to impart "photocurability" to the thermally conductive resin composition, you can select a photoradical polymerization initiator, and if you want to impart "heat curing or curing by redox reaction," you can select an organic peroxide. These radical polymerization initiators may be used alone or in combination of multiple agents.

[0026] The amount of component (C) added (blended amount) is not particularly limited, but for example, it is in the range of 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, even more preferably 0.5 to 10 parts by mass, and particularly preferably more than 2.5 parts by mass but less than 7.0 parts by mass, based on 100 parts by mass of the total amount of components (A) and (B). By keeping it within the above range, a thermally conductive resin composition can be obtained in which a cured product with even greater tensile strength and elongation properties can be obtained. If the thermally conductive resin composition contains two or more types of component (C), the amount of component (C) added (blended amount) is the total amount of component (C) relative to 100 parts by mass of the total amount of components (A) and (B).

[0027] Alternatively, the amount of component (C) added (blended amount) is preferably in the range of 0.1 to 5 parts by mass, more preferably 0.2 parts by mass or more and less than 1.0 part by mass, and particularly preferably 0.3 parts by mass or more and 0.8 parts by mass or less, per 100 parts by mass of the total thermal conductive resin composition. Within the above range, a thermal conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity. If the thermal conductive resin composition contains two or more types of component (C), the amount of component (C) added (blended amount) is the total amount of component (C) per 100 parts by mass of the total thermal conductive resin composition.

[0028] The photoradical initiator, which is component (C) used in the present invention, is not limited to any compound that generates radicals when irradiated with active energy rays. Examples of component (C) include acetophenone-based photoradical initiators, benzoin-based photoradical initiators, thioxanthone-based photoradical initiators, acylphosphine oxide-based photoradical initiators, and titanocene-based photoradical initiators. Among these, acetophenone-based photoradical initiators and acylphosphine oxide-based photoradical initiators are preferred from the viewpoint of excellent photocurability, and acetophenone-based photoradical initiators are particularly preferred. These may be used alone or in combination of two or more.

[0029] Examples of the aforementioned acetophenone-based photoradical initiators include, but are not limited to, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl-ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer. Commercially available products include IRGACURE184, DAROCUR1173 (manufactured by BASF), and DOUBLE BOND CHEMICAL IND.CO.,LTD.

[0030] Examples of the aforementioned acylphosphine oxide-based photoradical initiators include, but are not limited to, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0031] The organic peroxide component (C) used in the present invention is a compound that generates radical species upon heating to 50°C or higher or through a redox reaction. Using a redox reaction is preferable because it allows for the generation of radical species at room temperature. (C) The components are not particularly limited, but include, for example, ketone peroxide compounds such as methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetate peroxide, and acetylacetone peroxide; peroxyketal compounds such as 1,1-bis(t-butyl peroxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butyl peroxy)cyclohexane, 2,2-bis(t-butyl peroxy)octane, n-butyl-4,4-bis(t-butyl peroxy)valerate, and 2,2-bis(t-butyl peroxy)butane; t-butyl hydroperoxide, cumene hydroperoxide (cumene hydroperoxide), diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 2,5- Hydroperoxide compounds such as dimethylhexane-2,5-dihydroperoxide and 1,1,3,3-tetramethylbutylhydroperoxide; dialkylperoxide compounds such as di-t-butylperoxide, t-butylcumylperoxide, dicumylperoxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3; diacylperoxide compounds such as acetylperoxide, isobutyrylperoxide, octanoylperoxide, decanoylperoxide, lauroylperoxide, 3,5,5-trimethylhexanoylperoxide, succinic acid peroxide, benzoylperoxide, 2,4-dichlorobenzoylperoxide, and m-toluylperoxide;Peroxydicarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, bis-(4-t-butylcyclohexyl) peroxydicarbonate, dimyristyl peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di(3-methyl-3-methoxybutyl) peroxydicarbonate, diallyl peroxydicarbonate, etc.; t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, t-butyl peroxy-2-ethylhexanoate, cumyl peroxyneodecanoate, t-butyl-2-ethyl Examples include peroxyester compounds such as peroxyhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, di-t-butylperoxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxymalic acid, t-butylperoxyisopropyl carbonate, cumylperoxyoctoate, t-hexylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxyneohexanoate, t-hexylperoxyneohexanoate, and cumylperoxyneohexanoate; and acetylcyclohexylsulfonyl peroxide and t-butylperoxyallyl carbonate. These organic peroxides may be used alone or in combination. Of these, dialkyl peroxide compounds, peroxydicarbonate compounds, and peroxyester compounds are preferred from the viewpoint of curability. Furthermore, dialkyl peroxide compounds are mentioned as organic peroxides suitable for redox reactions.

[0032] When an organic peroxide is used as component (C), a curing accelerator may be added to promote the redox reaction. When component (C) includes an organic peroxide and a curing accelerator, the thermally conductive resin composition of the present invention can be used as a one-component composition. Such curing accelerators are not particularly limited, but preferably include saccharin (o-benzoix sulfimide), hydrazine compounds, amine compounds, mercaptan compounds, thiourea compounds, and metal-organic compounds. Among these, saccharin (o-benzoix sulfimide), hydrazine compounds, thiourea compounds, and metal-organic compounds are preferred because they yield cured products with excellent tensile strength and elongation. The curing accelerators may be used alone or in combination of several. Combination use is preferable from the viewpoint of curing acceleration, and among these, a combination of a hydrazine compound or thiourea compound and a metal-organic compound is preferred, with a combination of a hydrazine compound and a metal-organic compound being the most preferred.

[0033] Examples of the aforementioned hydrazine compounds include 1-acetyl-2-phenylhydrazine, 1-acetyl-2(p-tolyl)hydrazine, 1-benzoyl-2-phenylhydrazine, 1-(1',1',1'-trifluoro)acetyl-2-phenylhydrazine, 1,5-diphenyl-carbohydrazine, 1-fomyl-2-phenylhydrazine, 1-acetyl-2-(p-bromophenyl)hydrazine, 1-acetyl-2-(p-nitrophenyl)hydrazine, 1-acetyl-2-(2'-phenylethylhydrazine), ethylcarbazate, p-nitrophenylhydrazine, and p-trisulfonylhydrazide.

[0034] Examples of the amine compounds include heterocyclic secondary amines such as 2-ethylhexylamine, 1,2,3,4-tetrahydroquinone, and 1,2,3,4-tetrahydroquinaldine; heterocyclic tertiary amines such as quinoline, methylquinoline, quinaldine, and quinoxalinephenazine; aromatic tertiary amines such as N,N-dimethyl-p-toluidine, N,N-dimethylanisidine, and N,N-dimethylaniline; and azole compounds such as 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, and 3-mercaptobenzotrizole.

[0035] Examples of the mercaptan compounds include n-dodecyl mercaptan, ethyl mercaptan, butyl mercaptan, tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tristhioglycolate, and pentaerythritol tetrakisthioglycolate.

[0036] Examples of the thiourea compounds include ethylenethiourea, diethylthiourea, tetramethylthiourea, monoacetylthiourea, monobenzoylthiourea, diphenylthiourea, N,N'-dibutylthiourea, and N,N'-dioctylthiourea.

[0037] Examples of the aforementioned metal-organic compounds include iron pentadione, cobalt pentadione, cobalt neodecanoate, copper pentadione, copper propylenediamine, copper ethylenediamine, copper neodecanoate, iron naphthate, nickel naphthate, cobalt naphthate, copper naphthate, copper octate, iron hexoate, iron propionate, and acetylacetone vanadium.

[0038] The amount of curing accelerator added (blended amount) is not particularly limited, but for example, the amount of curing accelerator is 0.001 to 20 parts by mass, more preferably 0.002 to 15 parts by mass, even more preferably 0.003 to 10 parts by mass, and particularly preferably in the range of 0.3 to 2.0 parts by mass, per 100 parts by mass of the total of components (A) and (B). Within the above range, it is possible to obtain a thermally conductive resin composition that maintains thermal conductivity while producing a cured product with excellent tensile strength and elongation. If the thermally conductive resin composition contains two or more curing accelerators, the amount of curing accelerator added (blended amount) is the total amount of curing accelerators per 100 parts by mass of the total of components (A) and (B). Therefore, for example, when a hydrazine-based compound and a metal-organic compound are used in combination as a curing accelerator, the amount of curing accelerator added (mixing amount) is the total amount of the hydrazine-based compound and the metal-organic compound relative to 100 parts by mass of the total of components (A) and (B).

[0039] <(D) component> The plasticizer component (D) contained in the thermally conductive resin composition of the present invention, when combined with other components of the present invention, can be used to obtain a thermally conductive resin composition that maintains thermal conductivity while producing a cured product with excellent tensile strength and elongation properties. The component (D) is not particularly limited, but examples include polyether-based plasticizers, (meth)acrylic polymer-based plasticizers, phthalate ester-based plasticizers, polycarboxylic acid ester-based plasticizers, polybutadiene-based plasticizers, and polyisoprene-based plasticizers. Among these, polyether-based plasticizers and (meth)acrylic polymer-based plasticizers are preferred, and polyether-based plasticizers are particularly preferred. The component (D) is a compound that does not have a (meth)acryloyl group. These plasticizers may be used alone or in combination of several.

[0040] The polyether-based plasticizer is a compound having a polyether skeleton. The polyether skeleton refers to a skeleton having an alkylene oxide, such as polyethylene oxide, polypropylene oxide, or polybutylene glycol, with polypropylene oxide being preferred. The number of alkylene oxide repeats is not particularly limited, but is, for example, 3 to 300, more preferably 5 to 100, and particularly preferably in the range of 10 to 60.

[0041] The number-average molecular weight of component (D) is not particularly limited, but is, for example, in the range of 200 to 30,000, preferably in the range of 350 to 10,000, and particularly preferably in the range of 500 to 5,000. Unless otherwise specified, the number-average molecular weight was calculated by the standard polystyrene equivalent method using size exclusion chromatography (SEC). By being within the above range, it is possible to obtain a thermally conductive resin composition in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity.

[0042] There are no particular limitations on commercially available polyether-based plasticizers of component (D) mentioned above, but examples include PEG#300, PEG#400, PEG#600, PEG#1000, PEG#1500, PEG#15400, PEG#2000, PEG#4000, PEG#6000, PEG#1100, PEG#2000, Uniol D-700, D-1000, D-1200, D-2000, D-4000, PB-500, PB-700, PB-1000, and PB-2000 (manufactured by NOF Corporation).

[0043] The amount of component (D) added (blended amount) is not particularly limited, but for example, the amount of component (D) is 10 to 200 parts by mass, more preferably 15 to 150 parts by mass, and particularly preferably in the range of 20 to 100 parts by mass, relative to 100 parts by mass of the total of components (A) and (B). Within this range, it is possible to obtain a thermally conductive resin composition that maintains thermal conductivity while producing a cured product with excellent tensile strength and elongation. If the thermally conductive resin composition contains two or more types of component (D), the amount of component (D) added (blended amount) is the total amount of component (D) relative to 100 parts by mass of the total of components (A) and (B).

[0044] Alternatively, the amount of component (D) added (blended amount) is preferably in the range of 1 to 10 parts by mass, and more preferably 3 to 5 parts by mass, per 100 parts by mass of the total thermal conductive resin composition. Within this range, a thermal conductive resin composition can be obtained in which a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity. If the thermal conductive resin composition contains two or more types of component (D), the amount of component (D) added (blended amount) is the total amount of component (D) per 100 parts by mass of the total thermal conductive resin composition.

[0045] <(E) component> Component (E) of the present invention is not particularly limited as long as it is a thermally conductive powder. Component (E) is preferably a mixture of (E1) a thermally conductive powder with an average particle size of 0.01 μm or more and less than 2.0 μm, (E2) a thermally conductive powder with an average particle size of 2.0 μm or more and less than 20 μm, and (E3) a thermally conductive powder with an average particle size of 20 μm or more and less than 150 μm. That is, in a preferred embodiment of the present invention, component (E) includes (E1) a thermally conductive powder with an average particle size of 0.01 μm or more and less than 2.0 μm, (E2) a thermally conductive powder with an average particle size of 2.0 μm or more and less than 20 μm, and (E3) a thermally conductive powder with an average particle size of 20 μm or more and less than 150 μm. By using components (E1) to (E3) in combination with other components of the present invention, a remarkable effect is obtained in which tensile strength and elongation are excellent while maintaining thermal conductivity.

[0046] The average particle size of component (E1) is preferably 0.01 μm or more and less than 2.0 μm, more preferably 0.1 μm or more and 1.9 μm or less, even more preferably 0.2 μm or more and 1.8 μm or less, and particularly preferably 0.3 μm or more and 1.7 μm or less, from the viewpoint of excellent tensile strength and elongation.

[0047] Furthermore, the average particle size of component (E2) is preferably 2.0 μm or more and less than 20 μm (or 2.0 μm or more and less than 20.0 μm), more preferably 2.1 μm or more and 15 μm (or 2.1 μm or more and 15.0 μm), even more preferably 2.2 μm or more and 8 μm (or 2.2 μm or more and 8.0 μm), and particularly preferably 2.3 μm or more and 5 μm (or 2.3 μm or more and 5.0 μm).

[0048] Furthermore, the average particle size of component (E3) is preferably 20 μm to 150 μm, more preferably 23 μm to 100 μm, even more preferably 25 μm to 70 μm, and particularly preferably 27 μm to less than 50 μm, from the viewpoint of maintaining thermal conductivity while exhibiting excellent tensile strength and elongation properties.

[0049] Here, the average particle size of components (E1) to (E3) is the particle size (D50) at a cumulative volume ratio of 50% in the particle size distribution determined by laser diffraction scattering. In this specification, if components (E1) to (E3) are not perfectly spherical, the average particle size is the average of their shortest lengths.

[0050] In the thermally conductive resin composition of the present invention, the mass ratio of component (E1) to component (E3) ((E1) / (E3)) is not particularly limited, but for example, it is 0.08 to 1.00, preferably 0.09 to 0.90, more preferably 0.10 to 0.80, even more preferably 0.11 to 0.70, even more preferably 0.12 to 0.65, and particularly preferably 0.13 to 0.20. Being within the above range further enhances tensile strength and elongation while maintaining thermal conductivity.

[0051] In the thermally conductive resin composition of the present invention, the mass ratio of component (E2) to component (E3) ((E2) / (E3)) is not particularly limited, but for example, it is 0.15 to 1.50, preferably 0.17 to 1.20, more preferably 0.18 to 1.00, even more preferably 0.20 to 1.00, even more preferably 0.23 to 0.95, and particularly preferably 0.25 to 0.30. Being within the above range further enhances tensile strength and elongation while maintaining thermal conductivity.

[0052] Therefore, from the viewpoint of maintaining thermal conductivity while exhibiting excellent tensile strength and elongation, (E1) / (E3) is 0.08~1.0 (or 0.08~1.00) and (E2) / (E3) is 0.15~1.5 (or 0.15~1.50), preferably (E1) / (E3) is 0.09~0.9 (or 0.09~0.90) and (E2) / (E3) is 0.17~1.2 (or 0.17~1.20), and more preferably (E1) / (E3) is 0.10~0.8 (or 0.10~0.80) and (E2) / (E3) is 0.18~1.0 (or 0.18~1.00), more preferably (E1) / (E3) is 0.11~0.70 and (E2) / (E3) is 0.20~1.00, even more preferably (E1) / (E3) is 0.12~0.65 and (E2) / (E3) is 0.23~0.95, and particularly preferably (E1) / (E3) is 0.13~0.20 and (E2) / (E3) is 0.25~0.30.

[0053] The amount of component (E1) added (blended amount) is preferably 5 to 60 parts by mass, more preferably 5 to 30 parts by mass, even more preferably 7 to 28 parts by mass, and particularly preferably 8 to 15 parts by mass, based on 100 parts by mass of the total of (E1), (E2), and (E3). The amount of component (E2) added (blended amount) is preferably 10 to 65 parts by mass, more preferably 10 to 50 parts by mass, even more preferably 15 to 40 parts by mass, and particularly preferably more than 15 parts by mass and less than 25 parts by mass, based on 100 parts by mass of the total of (E1), (E2), and (E3). The amount of component (E3) added (blended amount) is preferably 30 to 85 parts by mass, more preferably 30 to 80 parts by mass, even more preferably 40 to 75 parts by mass, and particularly preferably 65 parts by mass or more and less than 75 parts by mass, based on 100 parts by mass of the total of (E1), (E2), and (E3). By keeping the amounts of components (E1) to (E3) within the above range, the material exhibits superior tensile strength and elongation while maintaining thermal conductivity.

[0054] Therefore, the mixing ratio of components (E1) to (E3) is preferably such that, out of a total of 100% by mass of (E1), (E2), and (E3), component (E1) is 5 to 60% by mass, component (E2) is 10 to 65% by mass, and component (E3) is 30 to 85% by mass; more preferably, component (E1) is 5 to 30% by mass, component (E2) is 10 to 50% by mass, and component (E3) is 30 to 80% by mass; even more preferably, component (E1) is 7 to 28% by mass, component (E2) is 15 to 40% by mass, and component (E3) is 40 to 75% by mass; particularly preferably, component (E1) is 8 to 15% by mass, component (E2) is more than 15% by mass but less than 25% by mass, and component (E3) is 65% by mass or more but less than 75% by mass. By keeping the mixing ratio of components (E1) to (E3) within the above range, the material exhibits superior tensile strength and elongation while maintaining thermal conductivity.

[0055] From the viewpoint of further improving the effects of the present invention, the content of component (E1) is, for example, 60 to 400 parts by mass, preferably 70 to 300 parts by mass, more preferably 80 to 250 parts by mass, and particularly preferably more than 80 parts by mass but less than 100 parts by mass, based on 100 parts by mass of the total of components (A) and (B). From a similar viewpoint, the content of component (E2) is preferably 110 to 400 parts by mass, more preferably 120 to 350 parts by mass, and particularly preferably 125 parts by mass or more but less than 200 parts by mass, based on 100 parts by mass of the total of components (A) and (B). From a similar viewpoint, the content of component (E3) is preferably 400 to 1200 parts by mass, more preferably 450 to 1000 parts by mass, and particularly preferably more than 450 parts by mass but less than 600 parts by mass, based on 100 parts by mass of the total of components (A) and (B).

[0056] The content of component (E) (i.e., the total content of components (E1) to (E3)) is not particularly limited, but for example, it is preferably 55 to 99% by mass, more preferably 70 to 95% by mass, even more preferably 75 to 93% by mass, and particularly preferably 80 to 90% by mass, relative to the entire thermal conductive resin composition of the present invention (100% by mass). Within the above range, the tensile strength and elongation are further improved while maintaining thermal conductivity.

[0057] The components (E1) to (E3) are preferably each independently at least one thermally conductive powder selected from the group consisting of alumina, zinc oxide, aluminum nitride, boron nitride, carbon, and diamond. In particular, due to their excellent thermal conductivity, each is more preferably independently at least one thermally conductive powder selected from the group consisting of alumina, aluminum nitride, and boron nitride. From the viewpoint of further improving the effects of the present invention, it is preferable that at least one of the components (E1) to (E3) is alumina, and it is particularly preferable that all of the components (E1) to (E3) are alumina. Furthermore, component (E) may be surface-treated. These may also be used individually or in combination of two or more types.

[0058] The shapes of the components (E1) to (E3) are preferably spherical or irregular.

[0059] In this specification, "spherical" includes not only perfectly spherical shapes, but also nearly spherical, elliptical, and other shapes. More specifically, "spherical" means having an average degree of circularity of 0.4 or higher.

[0060] In this specification, "irregular shape" refers to a shape having angles other than a sphere (e.g., needle-like, fibrous, scaly, dendritic, plate-like, fragmented, etc.). More specifically, "irregular shape" means having an average roundness of less than 0.4.

[0061] Furthermore, if component (E) is a mixture containing spherical thermally conductive powder and amorphous thermally conductive powder, a cured product with even greater thermal conductivity can be obtained.

[0062] Here, circularity is a value expressed as X / Y, where, for example, a particle projection image is acquired using a flow-type particle image analyzer FPIA-3000 (manufactured by Malvern Corporation), and the circumference of a circle having the same projection area as the particle projection image is X, and the length of the contour line of the particle projection image is Y. Furthermore, the average circularity is calculated by summing the circularity values ​​of each particle and dividing by the total number of particles.

[0063] From the viewpoint of excellent tensile strength and elongation, the shape of component (E1) is preferably spherical. On the other hand, considering the thermal conductivity of the cured product, the shape of component (E1) is preferably amorphous.

[0064] From the viewpoint of excellent tensile strength and elongation, the shape of component (E2) is preferably spherical. Also, from the viewpoint of excellent tensile strength and elongation, the shape of component (E3) is preferably spherical. Therefore, in one embodiment of the present invention, components (E2) and (E3) are spherical thermal conductive powders.

[0065] In a preferred embodiment of the present invention, component (E1) is a spherical or amorphous thermally conductive powder, and components (E2) and (E3) are spherical thermally conductive powders.

[0066] In a more preferred embodiment of the present invention, component (E1) is an amorphous thermally conductive powder, and components (E2) and (E3) are spherical thermally conductive powders.

[0067] There are no particular limitations on the commercially available products of component (E) mentioned above, but they can be obtained from, for example, Showa Denko Corporation, Nippon Light Metal Corporation, Nippon Steel & Sumitomo Metal Materials Corporation, Denka Corporation, and others.

[0068] <Optional ingredients> Additives such as bifunctional or polyfunctional (meth)acrylic monomers, styrene copolymers, silane coupling agents, inorganic fillers (excluding component (E) above), organic fillers (excluding component (E) above), flame retardants, preservative stabilizers, antioxidants, light stabilizers, rust inhibitors, solvents, pigments, dyes, tackifiers, and surfactants can be used in the thermally conductive resin composition of the present invention, to the extent that the objectives of the present invention are not impaired.

[0069] The thermally conductive resin composition of the present invention is not particularly limited as long as it contains a bifunctional or polyfunctional (meth)acrylic monomer. Among these, a tetrafunctional or more (meth)acrylic monomer is preferred.

[0070] The above-mentioned quadrifunctional or more (meth)acrylic monomers are not particularly limited, but examples include ditrimethylolpropanetetra(meth)acrylate, pentaerythritoltetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. These polymerizable monomers can be used alone or as a mixture of two or more.

[0071] For every 100 parts by mass of the total of components (A) and (B), the amount of the tetrafunctional or more polyfunctional (meth)acrylic monomer is preferably in the range of 0.1 to 15 parts by mass, more preferably in the range of 0.2 to 5 parts by mass, and particularly preferably in the range of 0.3 to 3 parts by mass. Being within the above range further enhances tensile strength and elongation. If the thermally conductive resin composition contains two or more tetrafunctional or more polyfunctional (meth)acrylic monomers, the amount of the tetrafunctional or more polyfunctional (meth)acrylic monomer added (blended amount) is the total amount of the tetrafunctional or more polyfunctional (meth)acrylic monomers relative to 100 parts by mass of the total of components (A) and (B).

[0072] The inorganic filler is not particularly limited, but examples include glass, fumed silica, talc, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum hydroxide, kaolin clay, dried clay minerals, dried diatomaceous earth, etc., with glass, fumed silica, talc, and mica being preferred among them.

[0073] The fumed silica can be incorporated to improve the mechanical strength of the cured product of the thermally conductive resin composition. Preferably, silica treated with hydrophobic agents such as organochlorosilanes, polyorganosiloxanes, or hexamethyldisilazane can be used. Specific examples of silica include commercially available products from Nippon Aerosil, such as Aerosil R974, R972, R972V, R972CF, R805, R812, R812S, R816, R8200, RY200, RX200, RY200S, and R202. These may be used alone or in combination.

[0074] Examples of the aforementioned organic fillers include polyethylene, polypropylene, nylon, crosslinked acrylic, crosslinked polystyrene, polyester, polyvinyl alcohol, polyvinyl butyral, and polycarbonate. Other examples include organic hollow fillers such as MMA-AN-MAN copolymers.

[0075] The amount of the filler added is not particularly limited, but for example, it is in the range of 0.01 to 500 parts by mass, more preferably 0.1 to 300 parts by mass, and especially preferably 0.5 to 150 parts by mass, relative to 100 parts by mass of the total amount of component (A) and component (B). These may be used alone or in combination of multiple fillers. The amount of the filler added refers to the total amount of inorganic and organic fillers. Therefore, if the thermally conductive resin composition contains two or more inorganic fillers or two or more organic fillers or a combination of one or more inorganic fillers and one or more organic fillers, the amount of the filler added is the total amount of fillers relative to 100 parts by mass of the total amount of component (A) and component (B).

[0076] Examples of the aforementioned flame retardants include aluminum hydroxide and magnesium hydroxide. In this invention, aluminum hydroxide or magnesium hydroxide is treated as a flame retardant rather than component (E) of the present invention.

[0077] <Manufacturing method> The thermally conductive resin composition of the present invention can be manufactured by conventionally known methods. For example, it can be manufactured by blending predetermined amounts of components (A) to (E) and other optional components, and mixing them using a mixing means such as a planetary mixer at a temperature of preferably 10 to 70°C, more preferably 20 to 50°C, and most preferably at room temperature (25°C) for preferably 0.1 to 5 hours, more preferably 30 minutes to 3 hours, and most preferably around 60 minutes. After the above mixing, a defoaming treatment may be performed if necessary.

[0078] <Curing method and cured product> The curing method of the thermally conductive resin composition of the present invention can be selected by selecting component (C) of the present invention, which can be photocured, heat cured, or redox cured. For example, if photocurability is desired for the thermally conductive resin composition, a photoradical polymerization initiator can be selected, and if curing by heat curing or redox reaction is desired, an organic peroxide can be selected.

[0079] When photocuring properties are imparted to the thermally conductive resin composition of the present invention, the curing conditions are as follows: The light source used to cure the thermally conductive resin composition of the present invention by irradiating it with light such as ultraviolet light or visible light is not particularly limited. Examples include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, electron beam irradiation devices, etc. The irradiation dose is 10 kJ / m³ from the viewpoint of the properties of the cured product. 2 It is preferable that it be greater than or equal to 15 kJ / m³, and more preferably 15 kJ / m³. 2 The above is a summary. Furthermore, the curing conditions when heat-curable properties are imparted to the thermally conductive resin composition of the present invention are not particularly limited, but for example, a temperature of 45°C or higher and less than 200°C is preferred, and more preferably 50°C or higher and less than 150°C. The curing time is not particularly limited, but at a temperature of 45°C or higher and less than 200°C, 3 minutes or more and less than 5 hours is preferred, and more preferably 10 minutes or more and within 3 hours. Furthermore, the curing conditions for the thermally conductive resin composition of the present invention containing a curing accelerator are not particularly limited, but for example, a temperature of 10°C or higher and less than 190°C is preferred, and more preferably 20°C or higher and less than 100°C. The curing time is not particularly limited, but 24 hours or more and 100 hours or less is preferred, and more preferably 36 hours or more and within 90 hours. A cured product obtained by curing the thermally conductive resin composition of the present invention is also part of the embodiments of the present invention. A joint formed by bonding with the thermally conductive resin composition of the present invention is also part of the embodiments of the present invention.

[0080] In other words, the present invention also provides a cured product obtained from the thermally conductive resin composition of the present invention. Furthermore, the present invention also provides a bonded body formed by bonding with the thermally conductive resin composition of the present invention.

[0081] <Two-component composition (second aspect)> The thermally conductive resin composition of the present invention can be used as a one-component composition, but it can also be used as a two-component composition. When used as a two-component composition, it is preferable that the composition is divided into agent A and agent B, with agent A containing at least component (C) and agent B containing at least a curing accelerator. That is, the present invention also provides a thermally conductive resin composition comprising the following agent A and agent B: Agent A: A composition containing the following components (A) to (E); (A) Component: Polyether backbone urethane (meth)acrylate having a (meth)acryloyl group at one end. (B) Component: Monofunctional (meth)acrylic monomer having a polyether backbone and not a urethane backbone (C) Component: Radical polymerization initiator (D) Component: Plasticizer (E) Component: Thermally conductive powder Agent B: A composition containing at least a curing accelerator.

[0082] By separating component (C) and the curing accelerator into different liquids, unnecessary reactions during storage can be suppressed, thereby improving storage stability. The two liquids can then be mixed before use, or applied separately and brought into contact to cure at room temperature (25°C). Components other than component (C) and the curing accelerator can be divided into any of the liquids in any proportion.

[0083] Examples of two-component compositions include a thermally conductive resin composition comprising the following components A and B. Agent A: A composition containing the following components (A) to (E); (A) Component: Polyether backbone urethane (meth)acrylate having a (meth)acryloyl group at one end. (B) Component: Monofunctional (meth)acrylic monomer having a polyether backbone and not a urethane backbone (C) Component: Radical polymerization initiator (D) Component: Plasticizer (E) Component: Thermally conductive powder Agent B: A composition comprising at least a curing accelerator and optionally comprising components (A), (B), (D), and (E).

[0084] In the above configuration, components (A), (B), (C), and the curing accelerator, component (D), and component (E) can be the same compounds as those specified above for <component (A)>, <component (B)>, <component (C)>, <component (D)>, and <component (E)>, respectively. The amount of each component added (mixing amount) can also be the same as those specified above.

[0085] Furthermore, if necessary, agents A and B may similarly contain the additives specified in <Optional Components> above. When agents A and B contain optional components, the optional components may be compounds similar to those specified in <Optional Components> above. The amount of optional components added (amount blended) may also be the same as that specified above.

[0086] The mixing ratio of agent A and agent B is not particularly limited, but is preferably such that each component is present in an appropriate amount as described above. Specifically, the mixing ratio of agent A and agent B (mixed mass ratio of agent A to agent B) is preferably 0.1:1 to 10:1, more preferably 0.3:1 to 3:1, and particularly preferably 0.5:1 to 1.5:1. By using the above mixing ratio, it is possible to obtain a thermally conductive resin composition that exhibits excellent tensile strength and elongation while maintaining thermal conductivity.

[0087] <Thermal conductive resin composition (third aspect)> According to the present invention, a cured product with excellent tensile strength and elongation is obtained while maintaining thermal conductivity. Specifically, the present invention also provides a thermally conductive resin composition comprising components (A), (B), (C), and (E), wherein the cured product has a tensile strength of 0.40 MPa or higher and an elongation of 60-1500%. (A) component: Urethane (meth)acrylate (B) Component: Monofunctional (meth)acrylic monomer without a urethane backbone (C) Component: Radical polymerization initiator (E) Component: Thermally conductive powder.

[0088] In the above embodiment, as component (A), in addition to the urethane (meth)acrylate specified in <Component (A)> above, urethane (meth)acrylate with a polybutadiene skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a hydrogenated polybutadiene skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a polycarbonate skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a polyether skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a polyester skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a castor oil skeleton having (meth)acryloyl groups at both ends, urethane (meth)acrylate with a polybutadiene skeleton having (meth)acryloyl groups at one end, and urethane (meth)acrylate with (meth)acryloyl groups at one end. Examples include urethane (meth)acrylate with a hydrogenated polybutadiene skeleton having an yl group, urethane (meth)acrylate with a polycarbonate skeleton having a (meth)acryloyl group at one end, urethane (meth)acrylate with a polyester skeleton having a (meth)acryloyl group at one end, and urethane (meth)acrylate with a castor oil skeleton having a (meth)acryloyl group at one end. Of these, urethane (meth)acrylate with a polyether skeleton having a (meth)acryloyl group at one end, as defined in <Component (A)> above, is preferably used. This makes it possible to obtain a thermally conductive resin composition that provides a cured product with excellent tensile strength and elongation while maintaining thermal conductivity. Furthermore, the amount of component (A) added (blended amount) can be the same as in <Component (A)> above, by replacing component (A) with component (A).

[0089] In the above embodiment, as component (B) above, in addition to the monofunctional (meth)acrylic monomer defined in <Component (B)>, ethyl (meth)acrylate, n-butyl (meth)acrylate, ter-butyl (meth)acrylate, isobutyl methacrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, glycidyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxy (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and benzyl (meth)acrylate. , phenyl(meth)acrylate, phenoxyethyl(meth)acrylate, nonylphenoxyethyl(meth)acrylate, butoxyethyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, trifluoroethyl(meth)acrylate, methacryloxyoxyethyl acid phosphate, 2-hydroxyethyl methacrylate phosphate, γ-methacryloxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, acryloylmorpholine, morpholinoethyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, diethylaminoethyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, N,Examples include N-dimethylaminopropyl (meth)acrylate, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, methacryloxyoctyltrimethoxysilane, neopentyl glycol di(meth)acrylate, stearic acid-modified pentaerythritol di(meth)acrylate, dicyclopentenyl diacrylate, di(meth)acryloyl isocyanurate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol pentaacrylate, and dipentaerythritol hexa(meth)acrylate. Of these, monofunctional (meth)acrylic monomers having a polyether skeleton and lacking a urethane skeleton, as defined in <Component (B)> above, are preferably used. This makes it possible to obtain a thermally conductive resin composition that exhibits even greater tensile strength and elongation while maintaining thermal conductivity. Furthermore, the amount of (B) component added (blended amount) can be the same as in <Component (B)> above, by substituting (B) component with (B) component.

[0090] In the above embodiment, components (C) and (E) can be the same compounds as those specified in <Component (C)> and <Component (E)> above. Furthermore, the amounts added (blended amounts) of components (C) and (E) can be the same amounts as those specified in <Component (C)> and <Component (E)> above.

[0091] The thermally conductive resin composition according to the above embodiment may also contain a plasticizer in addition to the above components (A"), (B"), (C), and (E). When the thermally conductive resin composition according to the above embodiment contains a plasticizer, the plasticizer can be the same compound as specified in <Component (D)> above. In this case, the amount of plasticizer added (amount blended) can also be the same amount as specified in <Component (D)> above.

[0092] Furthermore, the thermally conductive resin composition according to the above embodiment may contain other additives in addition to or instead of the plasticizer. When the thermally conductive resin composition according to the above embodiment contains other additives, the other additives may be compounds similar to those specified in <Optional Components> above. In this case, the amount of other additives added (amount blended) may also be the same as that specified in <Optional Components> above.

[0093] The elongation of the cured product of the thermally conductive resin composition of the present invention is preferably 60 to 1500%, more preferably 65 to 1000%, even more preferably 70 to 500%, and particularly preferably 80 to 500% from the viewpoint of high elongation. The method for measuring the elongation of the cured product is as follows, for example.

[0094] • Method for measuring the elongation of a hardened material A heat-conductive resin composition is prepared to a thickness (thickness after curing) of 1 mm, heated at 120°C for 20 minutes to cure, and a sheet-like cured material is produced. Test pieces are made by punching them out with a No. 3 dumbbell, and markings are made on the test pieces at 20 mm intervals. The ends of the test piece are fixed to the chuck so that the long axis of the test piece and the center of the chuck are in a straight line, and the test piece is pulled at a tensile speed of 500 mm / min until it is cut. During measurement, the test piece stretches and the distance between the markings widens, so the distance between the markings is measured with calipers until the test piece is cut. The percentage of elongation is taken as the initial distance between the markings and defined as the "elongation rate (%)".

[0095] Furthermore, from the viewpoint of high strength, the tensile strength of the cured product of the thermally conductive resin composition of the present invention is preferably 0.40 MPa or higher, more preferably 0.50 MPa or higher, and particularly preferably 0.60 MPa or higher. The method for measuring the tensile strength of the cured product is as follows, for example.

[0096] • Method for measuring the tensile strength of hardened material The tensile strength of the cured material conforms to JIS K6251 (2010). Specifically, a heat-conductive resin composition was prepared to a thickness (thickness after curing) of 1 mm, heated at 120°C for 20 minutes, and cured to produce a sheet-like cured material. Test pieces were made by punching them out with a No. 3 dumbbell. Both ends of the test piece were fixed to the chuck so that the long axis of the test piece and the center of the chuck were in a straight line. The test piece was pulled at a tensile speed of 500 mm / min using a universal testing machine (Tensilon, manufactured by Orientec Co., Ltd.), and the maximum load was measured. The strength at this maximum load was defined as the "tensile strength (MPa)".

[0097] Furthermore, the cured product of the thermally conductive resin composition of the present invention can maintain high thermal conductivity. Specifically, the thermal conductivity of the cured product is preferably 1.5 W / m·k or higher, more preferably 1.9 W / m·k or higher, and particularly preferably 2.0 W / m·k or higher. The method for measuring the thermal conductivity of the cured product is as follows, for example.

[0098] • Method for measuring the thermal conductivity of a cured material A thermally conductive resin composition is applied to a thickness of 500 μm, and a test specimen is prepared by heating at 120°C for 20 minutes. Thermal conductivity is measured by measuring the thermal diffusivity at 25°C using an ai-Phase Mobile 1u thermal diffusivity / thermal conductivity measuring device manufactured by i-Phase Corporation.

[0099] <Application Method> Methods for applying the thermally conductive resin composition of the present invention to a substrate include known adhesive and paint application methods. For example, methods such as dispensing using an automatic application machine, spraying, inkjet printing, screen printing, gravure printing, dipping, and spin coating can be used.

[0100] <Application> The thermally conductive resin composition of the present invention can be used in various fields such as the automotive, electrical and electronic components, and aerospace industries. However, because it can produce cured products with excellent tensile strength and extensibility while maintaining conductivity (especially thermal conductivity), it can be used in various applications such as heat dissipation of electronic substrates; heat dissipation of electronic devices such as mobile phones and personal computers; heat dissipation of lighting such as LEDs; heat dissipation of optical pickup modules; heat dissipation of camera modules; heat dissipation of sensing devices; heat dissipation of power semiconductors; heat dissipation of inverters for hybrid vehicles, fuel cell vehicles, and electric vehicles; heat dissipation of converters for hybrid vehicles, fuel cell vehicles, and electric vehicles; and heat dissipation of battery packs and ECU components for hybrid vehicles, fuel cell vehicles, and electric vehicles.

[0101] <Heat dissipation method> The cured product of the thermally conductive resin composition of the present invention can exhibit and maintain high thermal conductivity. Therefore, a heat dissipation method using the thermally conductive resin composition of the present invention includes a method in which the thermally conductive resin composition, which is one embodiment of the present invention, is applied to an electronic component or electrical / electronic component to dissipate the heat generated from the electronic component or electrical / electronic component to the outside. Examples of the electrical / electronic component include electronic circuit boards, mobile phones, personal computers and other electronic devices, lighting equipment such as LEDs, optical pickup modules, camera modules, sensing devices, power semiconductors, inverters for HEVs, FCVs, and EVs, converters for HEVs, FCVs, and EVs, and ECU components for HEVs, FCVs, and EVs.

[0102] In other words, the present invention provides an electronic component or electrical electronic component characterized by dissipating heat using a thermally conductive resin composition. [Examples]

[0103] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0104] <Preparation of thermally conductive resin composition> Examples 1-5, Comparative Examples 1-6 Each component was sampled in parts by mass as shown in Table 1, mixed in a mixer at room temperature (25°C) under light shielding for 60 minutes, and then degassed to obtain a thermally conductive resin composition. Detailed addition amounts are given in Table 1, and all values ​​are expressed in parts by mass. The components in Table 1 are as follows:

[0105] <(A) component> a1: Polyether-based urethane acrylate with an acryloyl group at one end and a weight-average molecular weight of 21,000 (manufactured by Negami Kogyo Co., Ltd.) a2: Polyether-based urethane acrylate with an acryloyl group at one end and a weight-average molecular weight of 30,000 (manufactured by Negami Kogyo Co., Ltd.) <(A) Comparative components> a'1: Polyether-based urethane acrylate with acryloyl groups at both ends and a weight-average molecular weight of 40,000 (Shiko UV-3700B, manufactured by Mitsubishi Chemical Corporation) a'2: A poly(meth)acrylic polymer having acryloyl groups at both ends and a weight-average molecular weight of 24,000 (RC-100C, manufactured by Kaneka Corporation). <(B) component> b1: Ethoxydiethylene glycol monoacrylate (Light Acrylate EC-A, manufactured by Kyoeisha Chemical Co., Ltd.) b2: Methoxynonaethylene glycol monoacrylate (AM-90G, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) <(B) Comparative components> b'1: Isobornyl acrylate (IBXA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) b'2: Phenoxyethyl acrylate (Light Acrylate PO-A, manufactured by Kyoeisha Chemical Co., Ltd.) b'3: Isononyl acrylate (INAA, manufactured by Osaka Organic Chemical Industry Co., Ltd.) <(C) component> c1: t-butylperoxy-2-ethylhexanoate (Perbutyl O, manufactured by Nippon Oil & Fats Co., Ltd.) c2: 2-Hydroxy-2-methyl-1-phenylpropan-1-one (Double Cure 173, manufactured by Double Bond Chemical Ind. Co., Ltd.) <(D) component> d1: Polypropylene glycol with a number-average molecular weight of 2000 and 34 repeating alkylene oxide groups (Uniol D-2000, manufactured by NOF Corporation). <(E) component> e1: Amorphous alumina powder with an average particle size of 0.5 μm (manufactured by Nippon Light Metal Co., Ltd.) e2: Spherical alumina powder with an average particle size of 3.0 μm (manufactured by Nippon Steel & Sumitomo Metal Materials Corporation) e3: Spherical alumina powder with an average particle size of 35.0 μm (manufactured by Nippon Steel & Sumitomo Metal Materials Co., Ltd.) The test methods used in the examples and comparative examples in Table 1, specifically tests (1) to (3), are as follows.

[0106] <(1) Thermal conductivity measurement> Each thermally conductive resin composition shown in Table 1 was applied to a thickness of 500 μm, and test specimens were prepared by heating at 120°C for 20 minutes. Thermal conductivity was measured by measuring the thermal diffusivity at 25°C using an ai-Phase Mobile 1u thermal diffusivity / thermal conductivity measuring device manufactured by i-Phase Corporation. Higher thermal conductivity is preferable because heat is transferred more easily. In particular, in this invention, a thermal conductivity of 1.5 W / m·k or higher is preferred, 1.9 W / m·k or higher is more preferred, and 2.0 W / m·k or higher is especially preferred.

[0107] <(2) Measurement of the tensile strength of the hardened material> Each thermally conductive resin composition in Table 1 was prepared to have a thickness (thickness after curing) of 1 mm, heated at 120°C for 20 minutes, and cured to produce a sheet-like cured material. Test pieces were made by punching them out with a No. 3 dumbbell. Both ends of the test piece were fixed to the chuck so that the long axis of the test piece and the center of the chuck were in a straight line. The test piece was pulled at a tensile speed of 500 mm / min using a universal testing machine (Tensilon, manufactured by Orientec Co., Ltd.), and the maximum load was measured. The strength at this maximum load was defined as "tensile strength (MPa)". The results are shown in Table 1. Details follow JIS K 6251 (2010). In this invention, from the viewpoint of high strength, a tensile strength of 0.40 MPa or higher is preferred, 0.50 MPa or higher is more preferred, and 0.60 MPa or higher is particularly preferred.

[0108] <(3) Method for measuring the elongation of a cured product> Each thermally conductive resin composition in Table 1 was prepared to have a thickness (thickness after curing) of 1 mm, heated at 120°C for 20 minutes, and cured to produce a sheet-like cured material. Test pieces were made by punching them out with a No. 3 dumbbell, and markings were made on the test pieces at 20 mm intervals. The test pieces were fixed to a chuck in the same manner as for measuring tensile strength, and pulled at a tensile speed of 500 mm / min using a universal testing machine (Tensilon, manufactured by Orientec Co., Ltd.) until the test piece was cut. During measurement, the test piece stretches and the distance between the markings widens, so the distance between the markings was measured with calipers until the test piece was cut. The initial distance between the markings was used as the reference, and the percentage of elongation was defined as the "elongation rate (%)". The results were evaluated based on the following criteria and are shown in Table 1. From the viewpoint of high elongation, the elongation rate is preferably 60-1500%, more preferably 65-1000%, even more preferably 70-500%, and particularly preferably 80-500%.

[0109] [Table 1]

[0110] As shown in Examples 1 to 5 of Table 1, it has been confirmed that the present invention is a thermally conductive resin composition that yields a cured product with excellent tensile strength and elongation while maintaining thermal conductivity.

[0111] Comparative Example 1 in Table 1 is a thermally conductive resin composition that does not contain component (D) of the present invention, and it can be seen that the cured product has poor extensibility. Comparative Examples 2 and 3 are thermally conductive resin compositions that use components a'1 and a'2, which are not component (A) of the present invention, and it can be seen that the cured products have poor extensibility. Comparative Examples 4 to 6 are thermally conductive resin compositions that use components b'1 to b'3, which are not component (B) of the present invention, and it can be seen that Comparative Example 4 is a cured product with poor extensibility, and Comparative Examples 5 and 6 are cured products with poor tensile strength.

[0112] Furthermore, the following two-component thermally conductive resin compositions were investigated.

[0113] <Preparation of components A and B of the thermally conductive resin composition of Example 6> Agent A (A) 55 parts by mass of component a1, (B) 35 parts by mass of component b1, (D) 30 parts by mass of component d1, (C) 1 part by mass of cumene hydroperoxide (c3), and (E) 80 parts by mass of component e1, 120 parts by mass of component e2, and 440 parts by mass of component e3 were added and mixed in a mixer at room temperature (25°C) for 60 minutes to obtain agent A.

[0114] • Agent B As component (A), 55 parts by mass of component a1; as component (B), 35 parts by mass of component b1; as component (D), 30 parts by mass of component d1; as a curing accelerator, 1 part by mass of 1-acetyl-2-phenylhydrazine (Aldrich reagent), 0.1 parts by mass of copper neodecanoate (Chuo Chemical Industry Co., Ltd.) with an active ingredient ratio of 5% by mass; and as component (E), 80 parts by mass of component e1, 120 parts by mass of component e2, and 440 parts by mass of component e3 were added. The mixture was then mixed in a mixer at room temperature (25°C) for 60 minutes to obtain component B.

[0115] <Preparation of Agents A' and B' of the thermally conductive resin composition of Comparative Example 7> · Agent A' As a comparative component of component (A), 55 parts by mass of component a'1 was added; as component (B), 35 parts by mass of component b1 was added; as component (D), 30 parts by mass of component d1 was added; as component (C), 1 part by mass of cumene hydroperoxide (c3) was added; and as component (E), 80 parts by mass of component e1, 120 parts by mass of component e2, and 440 parts by mass of component e3 were added. The mixture was then mixed in a mixer at room temperature (25°C) for 60 minutes to obtain agent A'.

[0116] · Agent B As a comparative component of component (A), 55 parts by mass of component a'1 was added; as component (B), 35 parts by mass of component b1 was added; as component (D), 30 parts by mass of component d1 was added; as a curing accelerator, 1 part by mass of 1-acetyl-2-phenylhydrazine (reagent) and 0.1 parts by mass of copper neodecanoate (manufactured by Chuo Chemical Industry Co., Ltd.) with an active ingredient ratio of 5% by mass were added; and as component (E), 80 parts by mass of component e1, 120 parts by mass of component e2, and 440 parts by mass of component e3 were added. The mixture was then mixed in a mixer at room temperature (25°C) for 60 minutes to obtain component B'.

[0117] <(4) Measurement of thermal conductivity> For each of the thermally conductive resin compositions in Example 6 and Comparative Example 7, 100 parts by mass of component A and 100 parts by mass of component B were placed in a polyethylene container and mixed for 10 minutes using a wooden stick at 25°C, after which the mixture was degassed. The mixture was then applied to a thickness of 500 μm and cured for 72 hours at 25°C to prepare test specimens. Thermal conductivity was measured by measuring the thermal diffusivity using an ai-Phase Mobile 1u thermal diffusivity / thermal conductivity measuring device manufactured by i-Phase Corporation at 25°C.

[0118] The results showed that Example 6 had a thermal conductivity of 2.0 W / m·k, while Comparative Example 7 had a thermal conductivity of 1.9 W / m·k. A higher thermal conductivity is preferable because it allows heat to transfer more easily. In particular, in this invention, a thermal conductivity of 1.5 W / m·k or higher is preferred.

[0119] <(5) Measurement of the tensile strength of the cured material> 100 parts by mass of component A and 100 parts by mass of component B of each thermally conductive resin composition from Example 6 and Comparative Example 7 were placed in a polyethylene container and mixed for 10 minutes using a wooden rod at 25°C, after which the mixture was degassed. Next, the mixture was set to a thickness (thickness after curing) of 1 mm and cured for 72 hours at 25°C to produce a sheet-like cured material. Test pieces were made by punching them out with a No. 3 dumbbell. Both ends of the test piece were fixed to the chuck so that the long axis of the test piece and the center of the chuck were in a straight line. The test piece was pulled at a tensile speed of 500 mm / min using a universal testing machine (Tensilon, manufactured by Orientec Co., Ltd.) and the maximum load was measured. The strength at this maximum load was defined as "tensile strength (MPa)". Details follow JIS K 6251 (2010).

[0120] The results showed that Example 6 had a tensile strength of 0.63 MPa, and Comparative Example 7 had a tensile strength of 0.90 MPa. Furthermore, from the viewpoint of achieving high strength in this invention, a tensile strength of 0.40 MPa or higher is preferred, 0.50 MPa or higher is more preferred, and 0.60 MPa or higher is particularly preferred.

[0121] <(6) Method for measuring the elongation of a cured product> 100 parts by mass of component A and 100 parts by mass of component B of each thermally conductive resin composition from Example 6 and Comparative Example 7 were placed in a polyethylene container and mixed for 10 minutes using a wooden stick at 25°C. The mixture was then cured to a thickness (thickness after curing) of 1 mm and allowed to cure for 72 hours at 25°C to produce a sheet-like cured material. Test pieces were made by punching them out with a No. 3 dumbbell, and markings were made on the test pieces at 20 mm intervals.

[0122] The test piece was fixed to a chuck in the same manner as for measuring tensile strength, and pulled at a tensile speed of 500 mm / min using a universal testing machine (Tensilon, manufactured by Orientec Co., Ltd.) until the test piece broke. During measurement, the test piece stretched and the distance between the gauge marks widened, so the distance between the gauge marks was measured with calipers until the test piece broke. The initial distance between the gauge marks was used as the baseline, and the percentage of stretching was defined as the "elongation rate (%)".

[0123] The results showed that Example 6 had an elongation rate of 70%, while Comparative Example 7 had an elongation rate of 40%. Furthermore, from the viewpoint of high stretchability, an elongation rate of 60% or higher is preferable, more preferably 65% ​​or higher, and particularly preferable 70% or higher. [Industrial applicability]

[0124] The present invention provides a thermally conductive resin composition that yields a cured product with excellent tensile strength and elongation while maintaining thermal conductivity, making it industrially useful as it can be used in a variety of fields.

[0125] This application is based on Japanese Patent Application No. 2021-097713, filed on June 11, 2021, the disclosures of which are referenced and incorporated in whole.

Claims

1. The following components (A) to (E): (A) Component: Polyether backbone urethane (meth)acrylate having a (meth)acryloyl group at one end. (B) Component: Monofunctional (meth)acrylic monomer having a polyether skeleton and not a urethane skeleton (C) Component: Radical polymerization initiator (D) Component: Polyether-based plasticizer (E) Component: Thermally conductive powder A thermally conductive resin composition comprising, A thermally conductive resin composition wherein, per 100 parts by mass of the thermally conductive resin composition, the content of component (A) is 3 to 15 parts by mass, the content of component (B) is 1 to 10 parts by mass, and the content of component (D) is 1 to 10 parts by mass.

2. The following are Agent A and Agent B: Agent A: A composition containing the following components (A) to (E). (A) Component: Polyether backbone urethane (meth)acrylate having a (meth)acryloyl group at one end. (B) Component: Monofunctional (meth)acrylic monomer having a polyether skeleton and not a urethane skeleton (C) Component: Radical polymerization initiator (D) Component: Polyether-based plasticizer (E) Component: Thermally conductive powder Agent B: A composition containing at least a curing accelerator. A thermally conductive resin composition comprising, A thermally conductive resin composition wherein, per 100 parts by mass of the thermally conductive resin composition, the content of component (A) is 3 to 15 parts by mass, the content of component (B) is 1 to 10 parts by mass, and the content of component (D) is 1 to 10 parts by mass.

3. The thermally conductive resin composition according to claim 1 or 2, comprising 20 to 90 parts by mass of component (A) with respect to a total of 100 parts by mass of component (A) and component (B).

4. The thermally conductive resin composition according to claim 1 or 2, comprising 10 to 200 parts by mass of component (D) with respect to a total of 100 parts by mass of component (A) and component (B).

5. The aforementioned (E) component is (E1) A thermally conductive powder with an average particle size of 0.01 μm or more and less than 2.0 μm, (E2) Thermally conductive powder with an average particle size of 2.0 μm or more and less than 20 μm, (E3) A thermally conductive powder with an average particle size of 20 μm or more and less than 150 μm, The thermally conductive resin composition according to claim 1 or 2.

6. The thermally conductive resin composition according to claim 5, wherein the mass ratio of (E1) / (E3) of component (E) is 0.08 to 1.00 and the mass ratio of (E2) / (E3) is 0.15 to 1.

50.

7. The thermally conductive resin composition according to claim 1 or 2, wherein the elongation of the cured product is 60 to 1500%.

8. A cured product obtained from the thermally conductive resin composition according to claim 1 or 2.

9. An electronic component characterized by dissipating heat using the thermally conductive resin composition described in claim 1 or 2.

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