Curable resin composition, cured product thereof, adhesive and laminate

Abstract

To provide a curable resin composition that excels in thermal conductivity and elongation after curing, and can be used as a low-viscosity, room-temperature-curable, two-component or multi-component adhesive.SOLUTION: A curable resin composition includes a first component including epoxy resin (A), and a second component including a specific epoxy curing agent (D). The curable resin composition further includes a polymer particle (B) with a core-shell structure including a core layer and a shell layer, and aluminum oxide (C) with a specific average particle size. The aluminum oxide (C) is contained in a specific amount.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a two-component or multi-component curable resin composition, a cured product thereof, an adhesive containing the curable resin composition, and a laminate formed using the adhesive.

Background Art

[0002] A cured product obtained by curing an epoxy resin composition is excellent in strength, heat resistance, water resistance, chemical resistance, electrical insulation, etc. Therefore, epoxy resin compositions are used as adhesives in a wide range of fields such as industrial and civil engineering applications. Currently, various adhesives containing epoxy resin compositions have been developed (for example, Patent Documents 1 to 7, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-mentioned conventional technologies had room for further improvement from the viewpoints of the handleability of the curable resin composition, and the thermal conductivity and elongation of the cured product.

[0005] One embodiment of the present invention has been made in view of the above-mentioned problems, and its objective is to provide a curable resin composition that can provide a cured product with excellent thermal conductivity and elongation, and can be used as a low-viscosity, room-temperature curing two-component or multi-component adhesive. [Means for solving the problem]

[0006] The present inventors, after diligent study to solve the aforementioned problems, have completed the present invention. That is, one embodiment of the present invention includes the following configuration.

[0007] [1] A two-component or multi-component curable resin composition comprising a first component containing an epoxy resin (A) and a second component containing an epoxy curing agent (D), wherein the curable resin composition further comprises polymer particles (B) having a core-shell structure including a core layer and a shell layer, and aluminum oxide (C), wherein the total mass of aluminum oxide (C) is 25% to 90% by mass of 100% by mass of the total mass of the curable resin composition, the average particle diameter of aluminum oxide (C) is 0.3 μm to 10.0 μm, and the epoxy curing agent (D) comprises at least one selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers.

[0008] [2] The curable resin composition according to [1], further comprising aluminum hydroxide (E).

[0009] [3] The curable resin composition according to [2], wherein the average particle size of the aluminum hydroxide (E) is 11 μm to 200 μm.

[0010] [4] The curable resin composition according to any one of [1] to [3], wherein the volume average particle diameter of the polymer particles (B) is 0.15 μm to 0.30 μm, the ratio of the mass of the core layer to the mass of the shell layer in the polymer particles (B) (mass of the core layer / mass of the shell layer) is 65 / 35 to 92 / 8, and the shell layer of the polymer particles (B) is a copolymer obtained by polymerizing a monomer component that contains 55% by mass or more of alkyl (meth)acrylate having 1 to 4 carbon atoms in the alkyl group in 100% by mass of the monomer component, and the monomer component contains 10% by mass to 100% by mass of alkyl (meth)acrylate having 1 carbon atom in the alkyl group and 0% by mass of alkyl (meth)acrylate having 4 carbon atoms in the alkyl group in 100% by mass of the monomer component.

[0011] [5] The curable resin composition according to any one of [1] to [4], wherein the epoxy curing agent (D) comprises (i) an amine compound (D1) having an active hydrogen equivalent of 300 g / eq to 1000 g / eq, and (ii) an amine compound (D2) having an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq.

[0012] [6] The curable resin composition according to any one of [1] to [4], wherein the epoxy curing agent (D) comprises (i) one or more amine compounds selected from the group consisting of amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, and (ii) one or more amine compounds selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, and modified amine-terminated polyethers.

[0013] 〔7〕The ratio of the number of moles of epoxy groups in the epoxy resin (A) to the number of moles of active hydrogen groups in the epoxy curing agent (D) (the number of moles of epoxy groups in the epoxy resin (A) / the number of moles of active hydrogen groups in the epoxy curing agent (D)) is 0.5 or more and 1.5 or less, and the curable resin composition according to any one of 〔1〕~〔6〕.

[0014] 〔8〕The polymer particles (B) have a diene rubber in the core layer, and the diene rubber is a butadiene rubber and / or a butadiene-styrene rubber, and the curable resin composition according to any one of 〔1〕~〔7〕.

[0015] 〔9〕The polymer particles (B) having the core-shell structure have an epoxy group in the shell layer, and the curable resin composition according to any one of 〔1〕~〔8〕.

[0016] 〔10〕 The polymer particles (B) have an epoxy group in the shell layer, and the content of the epoxy group in the shell layer is 0.1 mmol / g to 2.0 mmol / g with respect to the total mass of the shell layer, and the curable resin composition according to any one of 〔1〕~〔9〕.

[0017] 〔11〕The polymer particles (B) do not contain an epoxy group in the shell layer, and the curable resin composition according to any one of 〔1〕~〔8〕.

[0018] 〔12〕A cured product obtained by curing the curable resin composition according to any one of 〔1〕~〔11〕.

[0019] 〔13〕An adhesive containing the curable resin composition according to any one of 〔1〕~〔11〕.

[0020] 〔14〕The adhesive according to 〔13〕, wherein the adhesive is an adhesive for secondary batteries.

[0021] 〔15〕The adhesive according to 〔13〕, wherein the adhesive is an adhesive for vehicles.

[0022]

[16] Two base materials and an adhesive layer formed by curing the adhesive according to any one of

[13] to

[15] , wherein the adhesive layer joins the two base materials, a laminate.

Advantages of the Invention

[0023] According to one aspect of the present invention, there is an effect that a curable resin composition can be provided that can provide a cured product excellent in thermal conductivity and elongation and can be used as a room-temperature curable two-component or multi-component adhesive with low viscosity.

Modes for Carrying Out the Invention

[0024] One embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to each configuration described below, and various modifications are possible within the scope shown in the claims. Also, embodiments or examples obtained by appropriately combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, by combining the technical means disclosed in each embodiment, new technical features can be formed. All academic documents and patent documents described in this specification are incorporated herein by reference. Also, unless otherwise specified in this specification, "A to B" representing a numerical range is intended to mean "A or more (including A and greater than A) and B or less (including B and less than B)".

[0025] [1. Technical Idea of the Present Invention] For example, adhesives used to fix lithium-ion batteries to battery cases may be required to be curable at around room temperature (e.g., 5°C to 50°C) without requiring high-temperature heat treatment (e.g., above 50°C). This is because lithium-ion batteries are sensitive to heat. Similarly, adhesives used to fix lithium-ion batteries to battery cases may require high heat dissipation performance (specifically, high thermal conductivity) of the cured product (adhesive layer). Furthermore, from the perspective of reducing vibrations in vehicles and other equipment on which lithium-ion batteries are mounted, adhesives used when mounting lithium-ion batteries in vehicles and other equipment may require elongation of the cured product (adhesive layer). The conventional technologies described above had room for further improvement in terms of room-temperature curing, thermal conductivity, and elongation.

[0026] Therefore, the inventors diligently conducted research with the aim of providing a curable resin composition that can provide a cured product with excellent thermal conductivity and elongation, and that can be used as a room-temperature curing two-component or multi-component adhesive. As a result, the inventors independently discovered the following novel findings: a curable resin composition containing a large amount of aluminum oxide (for example, 25% to 90% by mass out of 100% by mass of the total mass of the curable resin composition), in addition to epoxy resin, polymer particles, and a specific epoxy curing agent, can provide a cured product with excellent thermal conductivity and elongation, and can be suitably used as a room-temperature curing adhesive.

[0027] Furthermore, during the course of diligent research, the inventors independently discovered a novel finding regarding the above-mentioned curable resin composition: that the viscosity of the curable resin composition may be high. Adhesives are sometimes required to have low viscosity from the viewpoint of workability. Therefore, the inventors further diligently researched with the aim of providing a curable resin composition that can provide a cured product with excellent thermal conductivity and elongation, and can be used as a low-viscosity, room-temperature curing, two-component or multi-component adhesive. As a result, the inventors independently discovered the following novel finding and completed the present invention: Surprisingly, a curable resin composition containing a large amount of aluminum oxide with a small average particle size (e.g., 0.3 μm to 10.0 μm) in addition to epoxy resin, polymer particles, and a specific epoxy curing agent (for example, 25% to 90% by mass in 100% by mass of the total mass of the curable resin composition) can provide a cured product with excellent thermal conductivity and elongation, and can be suitably used as a low-viscosity, room-temperature curing adhesive.

[0028] Generally, in adhesives containing fillers (e.g., inorganic particles), the viscosity of the filler increases as the average particle size of the filler decreases. However, in the course of diligent research, the inventors have independently discovered a novel finding: when aluminum oxide with a small average particle size (e.g., 0.3 μm to 10.0 μm) is included, the viscosity of the curable resin composition is surprisingly lower compared to when aluminum oxide with a large average particle size (e.g., exceeding 10.0 μm). This finding is the exact opposite of common technical knowledge in the field of adhesives and is a surprising and unprecedented novel finding.

[0029] [1. Curable resin composition] A curable resin composition according to one embodiment of the present invention is a two-component or multi-component curable resin composition comprising a first component containing an epoxy resin (A) and a second component containing an epoxy curing agent (D), wherein the curable resin composition further comprises polymer particles (B) having a core-shell structure including a core layer and a shell layer, and aluminum oxide (C), wherein the total mass of aluminum oxide (C) is 25% by mass or more and 90% by mass or less of the total mass of the curable resin composition, the average particle diameter of aluminum oxide (C) is 0.3 μm to 10.0 μm, and the epoxy curing agent (D) comprises at least one selected from the group consisting of aliphatic amines, alicyclic amines, amide amines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amide amines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers.

[0030] A cured product made from a curable resin composition can be provided by curing a curable resin composition according to one embodiment of the present invention using a known method.

[0031] In this specification, "a curable resin composition according to one embodiment of the present invention" may be referred to as "the present curable resin composition," "a cured product obtained by curing the curable resin composition" may be referred to as "the cured product," "a cured product obtained by curing the curable resin composition according to one embodiment of the present invention" may be referred to as "the present cured product," "an adhesive containing a curable resin composition" may be referred to as "the adhesive," "an adhesive containing a curable resin composition according to one embodiment of the present invention" may be referred to as "the adhesive," "a laminate formed by joining two substrates with an adhesive layer formed by curing an adhesive containing a curable resin composition" may be referred to as "a laminate," and "a laminate formed by joining two substrates with an adhesive layer formed by curing an adhesive containing a curable resin composition according to one embodiment of the present invention" may be referred to as "the present laminate."

[0032] One embodiment of the present invention has the advantage of providing a curable resin composition that, having the above configuration, can provide a cured product with superior thermal conductivity and elongation compared to conventional products, and can be suitably used as a low-viscosity, room-temperature curing two-component or multi-component adhesive. It can also be said that this curable resin composition can provide a cured product with superior thermal conductivity and elongation, and can provide a low-viscosity, room-temperature curing adhesive.

[0033] In this specification, "epoxy resin (A)", "polymer particles (B)", "aluminum oxide (C)", and "epoxy curing agent (D)" may be referred to as "component (A)", "component (B)", "component (C)", and "component (D)", respectively.

[0034] In this specification, thermal conductivity is evaluated by thermal conductivity (W / mK). A higher value of thermal conductivity (W / mK) for the cured product indicates superior thermal conductivity of the curable resin composition and the cured product. The method for measuring thermal conductivity (W / mK) will be described in detail in the following examples.

[0035] Furthermore, in this specification, viscosity is defined as the viscosity of the first and second components at 25°C and a shear rate of 5s. -1 This refers to the viscosity (Pa·s) value measured by [method / tool ​​name]. A lower viscosity indicates that the curable resin composition has better workability. The method for measuring viscosity will be explained in detail in the following examples.

[0036] Furthermore, in this specification, the elongation of the cured product is evaluated by the elongation at break (%), and the strength of the cured product is evaluated by the maximum tensile stress (MPa). The methods for measuring the maximum tensile stress (MPa) and elongation at break (%) will be described in detail in the following examples.

[0037] [1.1. Epoxy resin (A)] This curable resin composition contains epoxy resin (A) as the first component as the curable resin. Various epoxy resins can be used as the epoxy resin. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol S type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, novolac type epoxy resin, glycidyl ether type epoxy resin of bisphenol A propylene oxide adduct, hydrogenated bisphenol A (or F) type epoxy resin, fluorinated epoxy resin, flame-retardant epoxy resin such as glycidyl ether of tetrabromobisphenol A, p-oxybenzoic acid glycidyl ether type epoxy resin, m-aminophenol type epoxy resin, diaminodiphenylmethane-based epoxy resin, various alicyclic epoxy resins, N,N-diglycidylaniline, N,N-diglycidyl-o-toluside Examples of epoxy resins include triglycidyl isocyanurate, divinylbenzene dioxide, resorcinol diglycidyl ether, polyalkylene glycol diglycidyl ether, glycol diglycidyl ether, diglycidyl ester of aliphatic polybasic acid, glycidyl ether of divalent or higher polyhydric aliphatic alcohol such as glycerin, chelate-modified epoxy resin, rubber-modified epoxy resin, urethane-modified epoxy resin, hydantoin-type epoxy resin, epoxidized compounds of unsaturated polymers such as petroleum resin, aminoglycidyl ether resins, and epoxy compounds obtained by adding bisphenol A (or F) or polybasic acids to the above epoxy resins, but are not limited to these, and commonly used epoxy resins may be used. These epoxy resins may be used alone or in combination of two or more types.

[0038] Of these, the polyalkylene glycol diglycidyl ether can be more specifically identified as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like. The glycol diglycidyl ether can be more specifically identified as neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and the like. The aliphatic polybasic acid diglycidyl ester can be more specifically identified as dimer acid diglycidyl ester, adipic acid diglycidyl ester, sebacate acid diglycidyl ester, maleic acid diglycidyl ester, and the like. The diglycidyl ether of divalent or higher polyhydric aliphatic alcohol can be more specifically identified as trimethylolpropane triglycidyl ether, trimethylolethane triglycidyl ether, castor oil modified polyglycidyl ether, propoxylated glycerin triglycidyl ether, sorbitol polyglycidyl ether, and the like. Examples of epoxy compounds obtained by adding polybasic acids to epoxy resins include the addition reaction product of a tall oil fatty acid dimer (dimer acid) and a bisphenol A type epoxy resin, as described in International Publication No. 2010-098950.

[0039] The polyalkylene glycol diglycidyl ether, the glycol diglycidyl ether, the diglycidyl ester of the aliphatic polybasic acid, and the glycidyl ether of the divalent or higher polyhydric aliphatic alcohol (e.g., alkyl diglycidyl ether) are epoxy resins having relatively low viscosity. When used in combination with other epoxy resins such as bisphenol A type epoxy resin or bisphenol F type epoxy resin, they function as reactive diluents, improving the balance between the viscosity of the composition and the physical properties of the cured product. In other words, the epoxy resin (A) preferably contains polyepoxide as a reactive diluent. On the other hand, monoepoxide functions as a reactive diluent as described later, but is not included in epoxy resin (A). The content of these epoxy resins that function as reactive diluents is preferably 0.5 to 30% by mass, more preferably 2 to 20% by mass, and even more preferably 5 to 15% by mass in component (A).

[0040] The chelate-modified epoxy resin is a reaction product of an epoxy resin and a compound containing a chelate functional group (chelate ligand). When a curable resin composition to which this is added is used as an adhesive for vehicles, it can improve adhesion to metal substrate surfaces contaminated with oily substances. A chelate functional group is a functional group of a compound that has multiple coordination sites capable of coordinating to metal ions within its molecule. Examples include phosphorus-containing acid groups (e.g., -PO(OH)2), carboxylic acid groups (-CO2H), sulfur-containing acid groups (e.g., -SO3H), amino groups, and hydroxyl groups (especially hydroxyl groups adjacent to each other in an aromatic ring). Examples of chelate ligands include ethylenediamine, bipyridine, ethylenediaminetetraacetic acid, phenanthroline, porphyrin, and crown ether. A commercially available chelate-modified epoxy resin is ADEKA's ADEKA Resin EP-49-10N. The amount of chelate-modified epoxy resin used in component (A) is preferably 0.1 to 10% by mass, more preferably 0.5 to 3% by mass.

[0041] The rubber-modified epoxy resin is a reaction product obtained by reacting rubber with an epoxy group-containing compound, having an average of 1.1 or more epoxy groups per molecule, preferably 2 or more. Examples of rubber include rubber polymers such as acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), hydrogenated nitrile rubber (HNBR), ethylene propylene rubber (EPDM), acrylic rubber (ACM), butyl rubber (IIR), butadiene rubber, and polyoxyalkylenes such as polypropylene oxide, polyethylene oxide, and polytetramethylene oxide. The rubber polymer is preferably one having reactive groups such as amino groups, hydroxyl groups, or carboxyl groups at its ends. The rubber-modified epoxy resin is obtained by reacting these rubber polymers with epoxy resin in an appropriate blending ratio using a known method. Among these, acrylonitrile-butadiene rubber-modified epoxy resins and polyoxyalkylene-modified epoxy resins are preferred from the viewpoint of adhesive strength and impact-peel adhesion of the resulting curable resin composition, with acrylonitrile-butadiene rubber-modified epoxy resins being more preferred. Acrylonitrile-butadiene rubber-modified epoxy resins can be obtained, for example, by the reaction of carboxyl-terminated NBR (CTBN) with a bisphenol A type epoxy resin.

[0042] In the acrylonitrile-butadiene rubber-modified epoxy resin, the content of the acrylonitrile monomer component in the acrylonitrile-butadiene rubber is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 15 to 30% by mass, from the viewpoint of adhesive strength and impact-peel adhesion of the resulting curable resin composition. From the viewpoint of workability of the resulting curable resin composition, 20 to 30% by mass is particularly preferred.

[0043] In this specification, "workability of the curable resin composition" refers to the workability in operations (such as coating) using the curable resin composition.

[0044] Furthermore, for example, the addition reaction product of an amine-terminated polyether and an epoxy resin (hereinafter also referred to as "adduct") is also included in rubber-modified epoxy resins. The adduct can be easily manufactured by known methods, for example, as described in U.S. Patent No. 5084532 and U.S. Patent No. 6015865. The epoxy resin used in manufacturing the adduct can be, for example, a specific example of component (A) mentioned above, but bisphenol A type epoxy resin or bisphenol F type epoxy resin is preferred, and bisphenol A type epoxy resin is more preferred. Commercially available amine-terminated polyethers used in manufacturing the adduct can be, for example, Jeffamine D-230, Jeffamine D-400, Jeffamine D-2000, Jeffamine D-4000, and Jeffamine T-5000 manufactured by Huntsman.

[0045] The average number of epoxide-reactive end groups per molecule in the rubber is preferably 1.5 to 2.5, and more preferably 1.8 to 2.2. Note that "epoxide-reactive end groups" refers to end groups that are reactive with epoxy groups.

[0046] The number-average molecular weight of the rubber, measured by GPC in terms of polystyrene-equivalent molecular weight, is preferably 1000 to 10000, more preferably 2000 to 8000, and particularly preferably 3000 to 6000.

[0047] There are no particular restrictions on the method for producing rubber-modified epoxy resins; for example, they can be produced by reacting rubber with an epoxy group-containing compound in a large amount of epoxy group-containing compound. Specifically, it is preferable to react at least two equivalents of epoxy group-containing compound per equivalent of epoxy-reactive end groups in the rubber. It is more preferable to react at least enough epoxy group-containing compound to form a mixture of an adduct of rubber and the epoxy group-containing compound and free epoxy group-containing compound. For example, rubber-modified epoxy resins can be produced by heating at a temperature of 100 to 250°C in the presence of a catalyst such as phenyldimethylurea or triphenylphosphine. There are no particular restrictions on the epoxy group-containing compound used in the production of rubber-modified epoxy resins, but bisphenol A type epoxy resins and bisphenol F type epoxy resins are preferred, with bisphenol A type epoxy resins being more preferred. If an excess amount of epoxy group-containing compound is used in the production of rubber-modified epoxy resins, the unreacted epoxy group-containing compound remaining after the reaction shall not be included in the rubber-modified epoxy resin as defined herein.

[0048] In rubber-modified epoxy resins, the epoxy resin can be modified by pre-reacting it with a bisphenol component. The amount of bisphenol component used for modification is preferably 3 to 35 parts by mass, and more preferably 5 to 25 parts by mass, per 100 parts by mass of the rubber component in the rubber-modified epoxy resin. The cured product obtained by curing a curable resin composition containing the modified rubber-modified epoxy resin exhibits excellent adhesive durability after exposure to high temperatures, as well as excellent impact resistance at low temperatures.

[0049] The glass transition temperature (Tg) of the rubber-modified epoxy resin is not particularly limited, but is preferably -25°C or lower, more preferably -35°C or lower, even more preferably -40°C or lower, and particularly preferably -50°C or lower.

[0050] The number-average molecular weight of the rubber-modified epoxy resin is preferably 1,500 to 40,000, more preferably 3,000 to 30,000, and particularly preferably 4,000 to 20,000, as measured by GPC (Glycerin Proportional Concentration). The molecular weight distribution (ratio of mass-average molecular weight to number-average molecular weight) is preferably 1 to 4, more preferably 1.2 to 3, and particularly preferably 1.5 to 2.5.

[0051] Rubber-modified epoxy resins can be used alone or in combination of two or more types.

[0052] (A) The amount of rubber-modified epoxy resin used in component is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, even more preferably 5 to 30% by mass, and particularly preferably 10 to 20% by mass.

[0053] The urethane-modified epoxy resin is a reaction product obtained by reacting a compound containing a group reactive with isocyanate groups and epoxy groups with a urethane prepolymer containing isocyanate groups, having an average of 1.1 or more epoxy groups per molecule, preferably 2 or more. For example, a urethane-modified epoxy resin can be obtained by reacting a hydroxyl group-containing epoxy compound with a urethane prepolymer.

[0054] The number-average molecular weight of the urethane-modified epoxy resin is preferably 1,500 to 40,000, more preferably 3,000 to 30,000, and particularly preferably 4,000 to 20,000, as measured by GPC (Glycerin Proportional Concentration). The molecular weight distribution (ratio of mass-average molecular weight to number-average molecular weight) is preferably 1 to 4, more preferably 1.2 to 3, and particularly preferably 1.5 to 2.5.

[0055] Urethane-modified epoxy resins can be used alone or in combination of two or more types.

[0056] (A) The amount of urethane-modified epoxy resin used in component is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, even more preferably 5 to 30% by mass, and particularly preferably 10 to 20% by mass.

[0057] Among these epoxy resins, those having at least two epoxy groups per molecule are preferred because they exhibit high curability, high flexibility after curing, and excellent effect in improving impact peel resistance through the incorporation of core-shell polymer particles (B). Compounds having two epoxy groups per molecule are particularly preferred.

[0058] As component (A), among the epoxy resins mentioned above, bisphenol A type epoxy resin and bisphenol F type epoxy resin have a high elastic modulus of the resulting cured product, excellent heat resistance and adhesion, and are relatively inexpensive. Therefore, epoxy resin (A) is preferably bisphenol A type epoxy resin and / or bisphenol F type epoxy resin. Furthermore, since a curable resin composition that can provide a cured product with excellent heat resistance can be obtained at a low cost, epoxy resin (A) is particularly preferably bisphenol A type epoxy resin.

[0059] Furthermore, among the various epoxy resins, epoxy resins with an epoxy equivalent of less than 220 g / eq are preferred because the resulting cured product has a high elastic modulus and heat resistance, epoxy equivalents of 90 g / eq or more and less than 210 g / eq are more preferred, and 150 g / eq or more and less than 200 g / eq are even more preferred.

[0060] Here, epoxy equivalent (g / eq) refers to the number of grams of epoxy resin containing one equivalent of epoxy groups; in other words, it is the value obtained by dividing the molecular weight of the epoxy resin by the number of epoxy groups in one molecule of the epoxy resin.

[0061] In particular, bisphenol A type epoxy resins and bisphenol F type epoxy resins with an epoxy equivalent of less than 220 g / eq are preferred because they are liquid at room temperature and the resulting curable resin composition is easy to handle.

[0062] When component (A) contains, in 100% by mass of component (A), bisphenol A type epoxy resin and bisphenol F type epoxy resin with an epoxy equivalent of 220 g / eq or more and less than 5000 g / eq, preferably in an amount of 40% by mass or less, more preferably 20% by mass or less, the resulting cured product has excellent impact resistance, which is preferable.

[0063] [1.2. Polymer particles having a core-shell structure (B)] This curable resin composition contains polymer particles having a core-shell structure as component (B) in the first component and / or the second component. Here, "polymer particles (B) having a core-shell structure" means that polymer particles (B) have a core layer and a shell layer.

[0064] When a curable resin composition contains component (B), the toughness-improving effect of component (B) results in a cured product (e.g., an adhesive layer) with excellent elongation and impact-peel adhesion. Furthermore, when a curable resin composition contains component (B), the resulting cured product tends to have superior adhesive strength. Component (B) may be contained in only the first component, only the second component, or in both the first and second components. Component (B) may swell due to low-molecular-weight compounds contained in component (D) or other components in the second component. Therefore, from the viewpoint of storage stability of the composition, it is preferable that component (B) be contained in at least the first component, and more preferably in only the first component. Hereinafter, "polymer particles having a core-shell structure (B)" will also be referred to as "core-shell polymer particles (B)".

[0065] The core-shell polymer particles (B) may or may not have epoxy groups in their shell layer. In other words, the shell layer of the core-shell polymer particles (B) may or may not have epoxy groups. It is preferable that the core-shell polymer particles (B) have epoxy groups in their shell layer because the resulting cured product has excellent impact-resistant peel adhesion. When the shell layer of the core-shell polymer particles (B) has epoxy groups, the content of epoxy groups in the shell layer relative to the total mass of the shell layer of the core-shell polymer particles (B) is preferably greater than 0 mmol / g and 2.0 mmol / g or less, more preferably between 0.1 mmol / g and 2.0 mmol / g, and more preferably between 0.3 mmol / g and 1.5 mmol / g, from the viewpoint of elongation and impact-resistant peel adhesion of the resulting cured product. If the content of epoxy groups in the shell layer exceeds 0 mmol / g, the impact-resistant peel adhesion of the resulting cured product may be even better. If the epoxy group content of the shell layer is 2.0 mmol / g or less, the elongation of the resulting cured product may be better. It is presumed that the presence of epoxy groups in the shell layer suppresses aggregation of core-shell polymer particles (B), allowing the core-shell polymer particles (B) to be dispersed in the cured product as primary particles, thereby improving the impact-resistant peel adhesion of the cured product. Furthermore, it is presumed that by appropriately suppressing the amount of epoxy groups in the shell layer, the crosslinking density of the resulting cured product can be appropriately suppressed, increasing the molecular weight between crosslinking points of the cured product, thereby improving the elongation of the cured product. When the shell layer has epoxy groups, it is preferable that component (B) is contained only in the first component. Also, from the viewpoint of storage stability of the curable resin composition, it is preferable that the core-shell polymer particles (B) do not have epoxy groups in the shell layer. When core-shell polymer particles (B) are added to the second component which contains an epoxy curing agent (D) described later that has reactivity with epoxy groups, it is preferable that component (B) does not have epoxy groups in the shell layer.

[0066] The curable resin composition may contain (i) core-shell polymer particles (B) having epoxy groups in the shell layer in the first component, and (ii) core-shell polymer particles (B) not having epoxy groups in the shell layer in the second component.

[0067] In one embodiment of the present invention, the volume-average particle diameter of the core-shell polymer particles (B) is not particularly limited. Considering industrial productivity, the volume-average particle diameter (Mv) of the core-shell polymer particles (B) is preferably 0.01 μm to 2.00 μm, more preferably 0.03 μm to 0.60 μm, more preferably 0.05 μm to 0.40 μm, more preferably 0.10 μm to 0.30 μm, more preferably 0.15 μm to 0.30 μm, more preferably 0.16 μm to 0.28 μm, more preferably 0.17 μm to 0.27 μm, and even more preferably 0.18 μm to 0.25 μm. If the volume-average particle diameter (Mv) of the core-shell polymer particles (B) is (a) 0.01 μm or more, the viscosity of the curable resin composition is reduced, resulting in good workability. If it is (b) 2.00 μm or less, the polymerization time of component (B) is shortened, resulting in higher industrial productivity. In this specification, the volume-average particle diameter (Mv) of the core-shell polymer particles (B) can be measured for the latex of the polymer particles using a Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).

[0068] In the curable resin composition, it is preferable that the core-shell polymer particles (B) have a width at half maximum of 0.5 times or more and 1 time or less of the volume-average particle diameter in their number distribution, because this results in a curable resin composition with low viscosity and easy handling.

[0069] From the viewpoint of easily realizing the specific particle size distribution described above, it is preferable that there are two or more maximum values ​​in the particle size number distribution of the core-shell polymer particles (B), and from the viewpoint of manufacturing effort and cost, it is more preferable that there are two to three maximum values, and even more preferable that there are two maximum values. In particular, it is preferable to contain 10 to 90% by mass of core-shell polymer particles with a volume average particle size of 10 nm or more and less than 150 nm, and 90 to 10% by mass of core-shell polymer particles with a volume average particle size of 150 nm or more and 2000 nm or less.

[0070] It is preferable that the core-shell polymer particles (B) are dispersed in the curable resin composition as primary particles. In this specification, "core-shell polymer particles dispersed as primary particles" (hereinafter also referred to as "primary dispersion") means that the core-shell polymer particles are dispersed substantially independently (without contact) with each other, and this dispersion state can be confirmed, for example, by dissolving a portion of the curable resin composition in a solvent such as methyl ethyl ketone and measuring the particle size using a particle size analyzer that measures particle size using laser light scattering.

[0071] The value of volume-average particle diameter (Mv) / number-average particle diameter (Mn) obtained by the particle size measurement is not particularly limited, but is preferably 3.0 or less, more preferably 2.5 or less, even more preferably 2.0 or less, and particularly preferably 1.5 or less. If the volume-average particle diameter (Mv) / number-average particle diameter (Mn) is 3.0 or less, it is considered that the core-shell polymer particles (B) are well dispersed, and the physical properties such as elongation, impact resistance, and adhesion (adhesion strength) of the resulting cured product are good.

[0072] The volume-average particle diameter (Mv) / number-average particle diameter (Mn) can be calculated by measuring Mv using a Microtrac UPA (manufactured by Nikkiso Co., Ltd.) and dividing Mv by Mn.

[0073] Furthermore, "stable dispersion" of core-shell polymer particles means that the core-shell polymer particles remain dispersed steadily under normal conditions for a long period of time without agglomerating, separating, or settling in a continuous layer. It is also preferable that the distribution of core-shell polymer particles in the continuous layer does not change substantially, and that the "stable dispersion" can be maintained even when these compositions are heated to a safe extent to reduce viscosity and then stirred.

[0074] Core-shell polymer particles (B) may be used individually or in combination of two or more types.

[0075] The structure of the core-shell polymer particles (B) is not particularly limited, but it is preferable to have two or more layers. It is also possible to have a structure of three or more layers, consisting of an intermediate layer covering the core layer and a shell layer further covering this intermediate layer.

[0076] The following describes each layer of the core-shell polymer particles (B) in detail.

[0077] [1.2.1] Core Layer The core layer is preferably an elastic core layer having rubber properties in order to enhance the toughness of the cured product of the curable resin composition. In order to have rubber properties, the elastic core layer preferably has a gel content of 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. In this specification, gel content refers to the ratio of insoluble matter to the total amount of insoluble matter when 0.5 g of crumb obtained by solidification and drying is immersed in 100 g of toluene, left to stand at 23°C for 24 hours, and then the insoluble matter and soluble matter are separated.

[0078] The core layer preferably contains one or more selected from the group consisting of diene rubber, (meth)acrylate rubber, and organosiloxane rubber. The core layer preferably contains diene rubber because it has a high effect in improving the elongation and impact-peel adhesion of the resulting cured product, and because it has low affinity with epoxy resin (A), it is less likely to cause an increase in viscosity over time due to swelling of the core layer by component (A).

[0079] (Diene-based rubber) Examples of conjugated diene monomers that constitute the aforementioned diene rubber include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, and 2-methyl-1,3-butadiene. These conjugated diene monomers may be used individually or in combination of two or more.

[0080] The content of the conjugated diene monomer is preferably in the range of 50 to 100% by mass of the core layer, more preferably in the range of 70 to 100% by mass, and even more preferably in the range of 90 to 100% by mass. When the content of the conjugated diene monomer is 50% by mass or more, the elongation and impact-peel adhesion of the resulting cured product may be better.

[0081] Examples of vinyl monomers copolymerizable with conjugated diene monomers include vinylarenes such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; vinyl carboxylic acids such as acrylic acid and methacrylic acid; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; vinyl acetate; alkenes such as ethylene, propylene, butylene, and isobutylene; and polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. These vinyl monomers may be used individually or in combination of two or more. Styrene is particularly preferred.

[0082] The content of the vinyl monomer copolymerizable with the conjugated diene monomer is preferably in the range of 0 to 50% by mass of the core layer, more preferably in the range of 0 to 30% by mass, and even more preferably in the range of 0 to 10% by mass. When the content of the vinyl monomer copolymerizable with the conjugated diene monomer is 50% by mass or less, the elongation and impact-peel adhesion of the resulting cured product may be better.

[0083] Because of its high effectiveness in improving elongation and impact-peel adhesion, and because its low affinity with epoxy resin (A) makes it less likely for viscosity to increase over time due to swelling of the core layer, the diene rubber is preferably a butadiene rubber using 1,3-butadiene, and / or a butadiene-styrene rubber which is a copolymer of 1,3-butadiene and styrene, with butadiene rubber being more preferred. Furthermore, butadiene-styrene rubber is preferred because its transparency of the cured product can be increased by adjusting the refractive index.

[0084] ((meth)acrylate rubber) The (meth)acrylate-based rubber is preferably a rubber elastic body obtained by polymerizing a monomer mixture containing 50 to 100% by mass of at least one monomer selected from the group consisting of (meth)acrylate-based monomers, and 0 to 50% by mass of another vinyl-based monomer copolymerizable with the (meth)acrylate-based monomer.

[0085] Examples of the (meth)acrylate monomers include (i) alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, and behenyl (meth)acrylate; (ii) aromatic ring-containing (meth)acrylates such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate; (iii) 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. Examples include hydroxyalkyl (meth)acrylates such as (iv) glycidyl (meth)acrylates such as glycidyl (meth)acrylate and glycidylalkyl (meth)acrylate; (v) alkoxyalkyl (meth)acrylates; (vi) allylalkyl (meth)acrylates such as allyl (meth)acrylate and allylalkyl (meth)acrylate; and (vii) polyfunctional (meth)acrylates such as monoethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. These (meth)acrylate monomers may be used individually or in combination of two or more. Preferred (meth)acrylate monomers are ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0086] Other vinyl monomers copolymerizable with (meth)acrylate monomers include, for example, (i) vinylarenes such as styrene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; (ii) vinyl carboxylic acids such as acrylic acid and methacrylic acid; (iii) vinyl cyanides such as acrylonitrile and methacrylonitrile; (iv) vinyl halides such as vinyl chloride, vinyl bromide, and chloroprene; (v) vinyl acetate; (vi) alkenes such as ethylene, propylene, butylene, and isobutylene; and (vii) polyfunctional monomers such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. These vinyl monomers may be used individually or in combination of two or more. Styrene is particularly preferred because its refractive index can be easily increased.

[0087] (Organosiloxane-based rubber) Examples of the organosiloxane rubber include (i) polysiloxane polymers composed of alkyl or aryl 2-substituted silyloxy units such as dimethylsilyloxy, diethylsilyloxy, methylphenylsilyloxy, diphenylsilyloxy, and dimethylsilyloxy-diphenylsilyloxy; and (ii) polysiloxane polymers composed of alkyl or aryl 1-substituted silyloxy units such as organohydrogensilyloxy in which part of the alkyl in the side chain is substituted with a hydrogen atom. These polysiloxane polymers may be used individually or in combination of two or more. Among these, dimethylsilyloxy, methylphenylsilyloxy, and dimethylsilyloxy-diphenylsilyloxy are preferred because they can impart heat resistance to the cured product, and dimethylsilyloxy is most preferred because it is readily available. In an embodiment in which the core layer is formed from organosiloxane rubber, it is preferable that the polysiloxane polymer portion is contained in an amount of 80% by mass or more (more preferably 90% by mass or more) of the total organosiloxane rubber, relative to 100% by mass, in order not to impair the heat resistance of the cured product.

[0088] The glass transition temperature of the core layer (hereinafter sometimes simply referred to as "Tg") is preferably 0°C or lower, more preferably -20°C or lower, even more preferably -40°C or lower, and particularly preferably -60°C or lower, in order to increase the toughness of the resulting cured product.

[0089] Furthermore, the volume-average particle diameter of the core layer is not particularly limited, but is preferably 0.03 μm to 2 μm, more preferably 0.05 μm to 1 μm, more preferably 0.12 μm to 0.50 μm, more preferably 0.12 μm to 0.28 μm, and even more preferably 0.14 to 0.25 μm. When the volume-average particle diameter of the core layer is within this range, the core layer can be manufactured stably, and the heat resistance and impact resistance of the cured product can be good. In this specification, the volume-average particle diameter of the core layer can be measured for the latex of the core layer using Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.).

[0090] In the core-shell polymer particles (B) according to one embodiment of the present invention, the proportion of the core layer is not particularly limited. The proportion of the core layer is preferably 40% to 97% by mass, more preferably 60% to 95% by mass, even more preferably 70% to 93% by mass, and particularly preferably 80% to 90% by mass, with the total core-shell polymer particles (B) being 100% by mass. When the proportion of the core layer is 40% by mass or more, the elongation and impact-peel adhesion of the resulting cured product may be better. When the proportion of the core layer is 97% by mass or less, the core-shell polymer particles are less likely to aggregate, the curable resin composition may have a lower viscosity, and the workability may be better.

[0091] In the core-shell polymer particles (B) according to one embodiment of the present invention, the ratio of the mass of the core layer to the mass of the shell layer (mass of the core layer / mass of the shell layer) is not particularly limited. The ratio (mass of the core layer / mass of the shell layer) is preferably 65 / 35 to 92 / 8, more preferably 68 / 32 to 91 / 9, and more preferably 70 / 30 to 90 / 10, as this improves the workability of the curable resin composition and improves the elongation and impact resistance of the cured product. Having the ratio of the mass of the core layer to the mass of the shell layer (mass of the core layer / mass of the shell layer) in the polymer particles (B) within the above range has the advantage of lowering the viscosity of the curable resin composition and improving workability.

[0092] The core layer is often a single-layer structure, but it may also be a multilayer structure consisting of layers having rubber elasticity. Furthermore, if the core layer is a multilayer structure, the polymer composition of each layer may differ within the scope of the disclosure.

[0093] [1.2.2] Middle layer An intermediate layer may be formed between the core layer and the shell layer, if necessary. In particular, the following rubber surface crosslinking layer may be formed as the intermediate layer. From the viewpoint of improving the toughness, elongation, and impact-peel adhesion of the resulting cured product, it is preferable not to include an intermediate layer, and in particular, it is preferable not to include the following rubber surface crosslinking layer.

[0094] If an intermediate layer is present, the ratio of the intermediate layer to 100 parts by mass of the core layer is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 20 parts by mass, even more preferably 0.5 to 10 parts by mass, and particularly preferably 1 to 5 parts by mass.

[0095] The rubber surface crosslinked layer consists of an intermediate layer polymer obtained by polymerizing rubber surface crosslinked layer components comprising 30 to 100% by mass of a polyfunctional monomer having two or more radical polymerizable double bonds in one molecule, and 0 to 70% by mass of other vinyl monomers. This polymer has the effect of reducing the viscosity of the curable resin composition and improving the dispersibility of core-shell polymer particles (B) into component (A). It also has the effect of increasing the crosslinking density of the core layer and improving the grafting efficiency of the shell layer.

[0096] Specific examples of the polyfunctional monomers mentioned above do not include conjugated diene monomers such as butadiene, but include allylalkyl(meth)acrylates such as allyl(meth)acrylate and allylalkyl(meth)acrylate; allyloxyalkyl(meth)acrylates; polyfunctional(meth)acrylates having two or more (meth)acrylic groups such as (poly)ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate; diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene, but allyl methacrylate and triallyl isocyanurate are preferred. In this specification, (meth)acrylate means acrylate and / or methacrylate.

[0097] [1.2.3] Shell layer The outermost shell layer of the core-shell polymer particles is a polymer obtained by polymerizing the monomer for shell layer formation. The polymer constituting the shell layer (shell polymer) improves the compatibility between the core-shell polymer particles (B) and component (A), and plays a role in enabling the core-shell polymer particles (B) to be dispersed as primary particles in the curable resin composition or its cured product.

[0098] Such shell polymers are preferably grafted onto the core layer and / or intermediate layer. Hereinafter, when referring to "grafted onto the core layer," this also includes the configuration in which the shell polymer is grafted onto the intermediate layer when an intermediate layer is formed on the core layer. More precisely, it is preferable that the monomer component used to form the shell layer is graft polymerized onto the core polymer forming the core layer (if an intermediate layer is formed, the core polymer also includes the intermediate layer polymer that forms the intermediate layer; the same applies hereinafter) so that the shell polymer and the core polymer are substantially chemically bonded (if an intermediate layer is formed, it is also preferable that the shell polymer and the intermediate layer polymer are chemically bonded). That is, preferably, the shell polymer is formed by graft polymerizing the shell layer-forming monomer in the presence of the core polymer, thereby graft polymerizing onto the core polymer and covering part or all of the core polymer. This polymerization operation can be carried out by adding the shell polymer layer-forming monomer to the latex of the core polymer prepared in an aqueous polymer latex state and polymerizing it.

[0099] In the core-shell polymer particles (B), it is sufficient that at least a portion of the shell polymer forming the shell layer is graft polymerized (graft bonded) to the core polymer, and the core layer and shell layer do not need to form a complete layer structure. In other words, the shell polymer does not need to cover the entire core layer. In the core-shell polymer particles (B), a portion of the shell polymer may penetrate the core layer. In the core-shell polymer particles (B), it is preferable that a portion of the shell polymer covers the core layer, or in other words, it is preferable that a portion of the shell polymer is present on the outermost surface of the core-shell polymer particles (B) (forming the outermost layer).

[0100] The composition of the shell layer-forming monomer, that is, the type and content ratio of monomers contained in the shell layer-forming monomer, is not particularly limited. As the shell layer-forming monomer, from the viewpoint of compatibility and dispersibility of the core-shell polymer particles (B) in the curable resin composition, for example, aromatic vinyl monomers, vinyl cyanide monomers, or (meth)acrylate monomers are preferred, and (meth)acrylate monomers are more preferred. In particular, it is preferable that the shell layer-forming monomer contains metal methacrylate. These shell layer-forming monomers may be used individually or in appropriate combinations.

[0101] In other words, the types and proportions of constituent units contained in the shell layer are not particularly limited. From the viewpoint of compatibility and dispersibility of the core-shell polymer particles (B) in the curable resin composition, the shell layer preferably contains constituent units derived from one or more monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylate monomers, and more preferably contains constituent units derived from (meth)acrylate monomers. In particular, the shell layer preferably contains constituent units derived from metal methacrylate.

[0102] The total amount of aromatic vinyl monomer, vinyl cyanide monomer, and (meth)acrylate monomer is preferably 10.0% to 99.5% by mass, more preferably 50.0% to 99.0% by mass, even more preferably 65.0% to 98.0% by mass, particularly preferably 67.0% to 80.0% by mass, and most preferably 67.0% to 85.0% by mass, based on 100% by mass of the monomer for shell layer formation.

[0103] In other words, the shell layer preferably contains 10.0% to 99.5% by mass, more preferably 50.0% to 99.0% by mass, even more preferably 65.0% to 98.0% by mass, particularly preferably 67.0% to 80.0% by mass, and most preferably 67.0% to 85.0% by mass, of constituent units derived from one or more monomers selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylate monomers, per 100% by mass of the shell layer (shell polymer).

[0104] Specific examples of the aromatic vinyl monomers include vinylbenzenes such as styrene, α-methylstyrene, p-methylstyrene, and divinylbenzene.

[0105] Specific examples of the vinyl cyanide monomer include acrylonitrile or methacrylonitrile.

[0106] Specific examples of the (meth)acrylate monomer include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; and hydroxyalkyl (meth)acrylates.

[0107] Specific examples of the aforementioned hydroxyalkyl (meth)acrylate include, for example, hydroxylinear alkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate (especially hydroxylinear C1-6 alkyl (meth)acrylate); caprolactone-modified hydroxy (meth)acrylate; hydroxybranched alkyl (meth)acrylates such as α-(hydroxymethyl)acrylate and α-(hydroxymethyl)acrylate; and hydroxyl group-containing (meth)acrylates such as mono(meth)acrylates of polyester diols (especially saturated polyester diols) obtained from divalent carboxylic acids (such as phthalic acid) and divalent alcohols (such as propylene glycol).

[0108] The shell layer according to one embodiment of the present invention is preferably a copolymer obtained by polymerizing a shell layer-forming monomer containing 55% by mass or more of alkyl (meth)acrylate having 1 to 4 carbon atoms in the alkyl group in 100% by mass of the shell layer-forming monomer. In other words, the shell layer according to one embodiment of the present invention preferably contains 55% by mass or more of constituent units derived from alkyl (meth)acrylate having 1 to 4 carbon atoms in the alkyl group in 100% by mass of the shell layer. The shell layer according to one embodiment of the present invention is preferably a copolymer obtained by polymerizing a monomer component containing 65% by mass or more of alkyl (meth)acrylate having 1 to 4 carbon atoms in the alkyl group in 100% by mass of the shell layer-forming monomer, more preferably a copolymer obtained by polymerizing a monomer component containing 75% by mass or more, even more preferably a copolymer obtained by polymerizing a monomer component containing 78% by mass or more, and particularly preferably a copolymer obtained by polymerizing a monomer component containing 83% by mass or more. When the monomer for forming the shell layer contains alkyl (meth)acrylates having 1 to 4 carbon atoms in the alkyl group within the range described above, it has the advantage of improving the workability of the curable resin composition.

[0109] Specific examples of alkyl(meth)acrylates in which the alkyl group has 1 to 4 carbon atoms include alkyl (meth)acrylate esters such as methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, and t-butyl(meth)acrylate.

[0110] In one embodiment of the present invention, the monomer for forming a shell layer preferably contains 10% to 100% by mass of alkyl (meth)acrylate having one carbon atom in the alkyl group, and 0% to 80% by mass of alkyl (meth)acrylate having four carbon atoms in the alkyl group, in 100% by mass of the monomer for forming the shell layer. In other words, in one embodiment of the present invention, the shell layer preferably contains 10% to 100% by mass of constituent units derived from alkyl (meth)acrylate having one carbon atom in the alkyl group, and 0% to 80% by mass of constituent units derived from alkyl (meth)acrylate having four carbon atoms in the alkyl group.

[0111] The monomer for forming a shell layer according to one embodiment of the present invention more preferably contains 11% to 95% by mass of alkyl(meth)acrylate having one carbon atom in the alkyl group, more preferably 12% to 92% by mass, even more preferably 13% to 55% by mass, and particularly preferably 14% to 50% by mass, of the monomer for forming a shell layer. The shell layer forming monomer according to one embodiment of the present invention preferably contains 1% to 89% by mass of alkyl(meth)acrylate having 4 carbon atoms in the alkyl group, more preferably 1% to 88% by mass, 1% to 87% by mass, 1% to 86% by mass, more preferably 1% to 78% by mass, 2% to 76% by mass, 5% to 76% by mass, 8% to 76% by mass, 20% to 74% by mass, 35% to 72% by mass, even more preferably 35% to 60% by mass, and particularly preferably 35% to 50% by mass, in 100% by mass of the shell layer forming monomer. When the shell layer-forming monomer constituting the shell layer of the core-shell polymer particles (B) contains alkyl (meth)acrylates with one carbon atom in the alkyl group and / or alkyl (meth)acrylates with four carbon atoms in the alkyl group within the range described above, the interaction between the core-shell polymer particles (B) and component (C) can be appropriately controlled, which has the advantage of keeping the viscosity of the curable resin composition low and improving workability.

[0112] As alkyl(meth)acrylates with one carbon atom in the alkyl group, methyl methacrylate and methyl acrylate can be used. As alkyl(meth)acrylates with four carbon atoms in the alkyl group, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, and t-butyl methacrylate can be used.

[0113] From the viewpoint of improving the workability of the curable resin composition, the monomer for forming the shell layer according to one embodiment of the present invention preferably has both alkyl (meth)acrylate having one carbon atom in the alkyl group and alkyl (meth)acrylate having four carbon atoms in the alkyl group, and more preferably contains 13% to 55% by mass of alkyl (meth)acrylate having one carbon atom in the alkyl group and 20% to 74% by mass of alkyl (meth)acrylate having four carbon atoms in the alkyl group. In other words, the shell layer according to one embodiment of the present invention preferably has both constituent units derived from alkyl (meth)acrylate having one carbon atom in the alkyl group and constituent units derived from alkyl (meth)acrylate having four carbon atoms in the alkyl group, and preferably contains 13% to 55% by mass of constituent units derived from alkyl (meth)acrylate having one carbon atom in the alkyl group and 20% to 74% by mass of constituent units derived from alkyl (meth)acrylate having four carbon atoms in the alkyl group.

[0114] Furthermore, in the shell layer-forming monomer according to one embodiment of the present invention, it is not necessary for the total amount of alkyl (meth)acrylates with one carbon atom in the alkyl group and alkyl (meth)acrylates with four carbon atoms in the alkyl group to be 100% by mass of the shell layer-forming monomer. In other words, in the shell layer-forming monomer according to one embodiment of the present invention, it is sufficient if the total amount of monomers other than (a) alkyl (meth)acrylates with one carbon atom in the alkyl group, (b) alkyl (meth)acrylates with four carbon atoms in the alkyl group, and (c) alkyl (meth)acrylates with one carbon atom in the alkyl group and alkyl (meth)acrylates with four carbon atoms in the alkyl group is 100% by mass of the shell layer-forming monomer. That is, the shell layer-forming monomer according to one embodiment of the present invention may contain monomers other than alkyl (meth)acrylates with one carbon atom in the alkyl group and alkyl (meth)acrylates with four carbon atoms in the alkyl group.

[0115] When the shell layer forming monomer contains aromatic vinyl monomer and / or vinyl cyanamide monomer, that is, when the shell layer contains constituent units derived from aromatic vinyl monomer and / or vinyl cyanamide monomer, the compatibility and dispersibility of the core-shell polymer particles (B) in the curable resin composition are good. On the other hand, by reducing the interaction between component (B) and component (C), the workability of the curable resin composition can be improved. Therefore, in one embodiment of the present invention, the content of aromatic vinyl monomer in 100% by mass of the shell layer forming monomer may be 30% by mass or less, 20% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less. In other words, in one embodiment of the present invention, the content of constituent units derived from aromatic vinyl monomer in 100% by mass of the shell layer may be 30% by mass or less, 20% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less. Furthermore, from the viewpoint of improving the workability of the curable resin composition, in one embodiment of the present invention, the content of vinyl cyanamide monomer in 100% by mass of the shell layer forming monomer may be 10% by mass, 8% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, or 2% by mass or less. In other words, in one embodiment of the present invention, the content of constituent units derived from vinyl cyanamide monomer in 100% by mass of the shell layer is preferably 10% by mass or less, 8% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, or 2% by mass or less.

[0116] The shell layer may further contain a (meth)acrylate monomer having 5 or more carbon atoms in the alkyl group. In other words, the shell layer may further contain constituent units derived from a (meth)acrylate monomer having 5 or more carbon atoms in the alkyl group. Specific examples of (meth)acrylate monomers having 5 or more carbon atoms in the alkyl group include 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate.

[0117] In order to maintain a good dispersion state without aggregation of core-shell polymer particles (B) in cured products or curable resin compositions, it is preferable to include a reactive group-containing monomer as a shell layer-forming monomer, which contains one or more selected from the group consisting of epoxy groups, oxetane groups, hydroxyl groups, amino groups, imide groups, carboxylic acid groups, carboxylic acid anhydride groups, cyclic esters, cyclic amides, benzoxazine groups, and cyanate ester groups, from the viewpoint of chemically bonding with component (A), and in particular monomers having epoxy groups are preferred.

[0118] The shell layer is preferably a polymer formed by graft polymerization of a shell layer-forming monomer containing an epoxy group onto a core layer (core polymer). This configuration has the advantage that the resulting cured product has excellent impact-peel adhesion.

[0119] From the viewpoint of elongation of the cured product, impact-peel adhesion, and storage stability of the curable resin composition, monomers having epoxy groups are preferably present in an amount of 0% to 90% by mass, more preferably 1% to 50% by mass, even more preferably 2% to 35% by mass, and particularly preferably 3% to 20% by mass, in 100% by mass of the monomers for forming the shell layer.

[0120] In other words, the shell layer preferably has constituent units derived from monomers having epoxy groups. Furthermore, the shell layer preferably contains 0% to 90% by mass of constituent units derived from monomers having epoxy groups, more preferably 1% to 50% by mass, even more preferably 2% to 35% by mass, and particularly preferably 3% to 20% by mass, of the shell layer by mass.

[0121] Monomers having epoxy groups are preferably used for forming the shell layer, and more preferably used solely for forming the shell layer.

[0122] Furthermore, using a polyfunctional monomer having two or more radically polymerizable double bonds as a monomer for forming the shell layer is preferable because it prevents swelling of core-shell polymer particles in the curable resin composition and tends to result in a lower viscosity and better handling of the curable resin composition. On the other hand, from the viewpoint of improving the toughness, elongation, and impact-peel adhesion of the resulting cured product, it is preferable not to use a polyfunctional monomer having two or more radically polymerizable double bonds as a monomer for forming the shell layer.

[0123] The polyfunctional monomer may be present in 100% by mass of the shell layer-forming monomer in amounts of, for example, 0% to 20% by mass, preferably 1% to 20% by mass, and more preferably 5% to 15% by mass.

[0124] Specific examples of monomers having a hydroxyl group as the reactive group-containing monomer include, for example, hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate (especially hydroxyl linear C1-6 alkyl (meth)acrylate); caprolactone-modified hydroxy (meth)acrylate; hydroxyl branched alkyl (meth)acrylates such as α-(hydroxymethyl)acrylate and α-(hydroxymethyl)acrylate; and hydroxyl group-containing (meth)acrylates such as mono(meth)acrylates of polyester diols (especially saturated polyester diols) obtained from divalent carboxylic acids (phthalic acid, etc.) and divalent alcohols (propylene glycol, etc.).

[0125] Specific examples of monomers having the epoxy group include glycidyl group-containing vinyl monomers such as glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and allyl glycidyl ether.

[0126] Specific examples of polyfunctional monomers having two or more radical polymerizable double bonds include the same monomers as those described above, but allyl methacrylate and triallyl isocyanurate are preferred.

[0127] The shell layer according to one embodiment of the present invention is preferably a polymer of the following shell layer forming monomers (total 100% by mass): (a) aromatic vinyl monomer (especially styrene) 0 to 50% by mass (preferably 1 to 50% by mass, more preferably 2 to 48% by mass), (b) vinyl cyanide monomer (especially acrylonitrile) 0 to 50% by mass (preferably 0 to 30% by mass, more preferably 10 to 25% by mass), (c) (meth)acrylate monomer (especially methyl methacrylate) 0 to 100% by mass (preferably 5 to 100% by mass, more preferably 70 to 95% by mass), and (d) monomer having an epoxy group (especially glycidyl methacrylate) 1 to 50% by mass (preferably 2 to 35% by mass, more preferably 3 to 20% by mass). This makes it possible to achieve a good balance between the desired toughness improvement effect and mechanical properties.

[0128] Furthermore, the shell layer according to one embodiment of the present invention is preferably a polymer of the following shell layer forming monomers (total 100% by mass): (a) 10 to 100% by mass (preferably 11 to 95% by mass, particularly preferably 14 to 50% by mass) of alkyl (meth)acrylate monomers having 1 carbon atom in the alkyl group (particularly methyl methacrylate), (b) 0 to 80% by mass (preferably 1 to 78% by mass, particularly preferably 35 to 72% by mass) of alkyl (meth)acrylate monomers having 4 carbon atoms in the alkyl group (particularly butyl acrylate), (c) 30% by mass or less (preferably 10% by mass or less, more preferably 0% by mass) of aromatic vinyl monomers (particularly styrene), (d) 10% by mass or less (preferably 5% by mass or less, more preferably 0%) of vinyl cyanide monomers (particularly acrylonitrile), and (e) 0 to 45% by mass (preferably 0 to 25% by mass, more preferably 3 to 20% by mass) of a combination of shell layer forming monomers (total 100% by mass). This allows for a good balance between improving the desired toughness and achieving workability.

[0129] These monomer components may be used individually or in combination of two or more. The shell layer may be formed by including other monomer components in addition to the above monomer components.

[0130] The glass transition temperature of the shell layer (hereinafter sometimes simply referred to as "Tg") is preferably -45°C to 110°C, more preferably -40°C to 100°C, even more preferably -35°C to 50°C, and particularly preferably -30°C to 10°C, from the viewpoint of improving the workability of the curable resin composition.

[0131] The grafting rate of the shell layer is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. When the grafting rate is 70% or more, the curable resin composition may have a lower viscosity.

[0132] The method for calculating the graft rate is as follows. First, an aqueous latex containing core-shell polymer particles is coagulated and dehydrated, and finally dried to obtain a core-shell polymer particle powder. Next, 2 g of the core-shell polymer particle powder is immersed in 100 g of methyl ethyl ketone (MEK) at 23°C for 24 hours, after which the MEK-soluble portion is separated from the MEK-insoluble portion, and then the methanol-insoluble portion is separated from the MEK-soluble portion. The graft rate is then calculated by determining the ratio of the MEK-insoluble portion to the total amount of MEK-insoluble portion and methanol-insoluble portion.

[0133] [1.2.4] Method for producing core-shell polymer particles (Method of manufacturing the core layer) The core layer constituting the core-shell polymer particles (B) can be produced by, for example, emulsion polymerization, suspension polymerization, or microsuspension polymerization, and methods described in, for example, International Publication No. 2005 / 028546 or International Publication No. 2006 / 070664 can be used.

[0134] (Method for forming shell layers and intermediate layers) The intermediate layer can be formed by polymerizing the intermediate layer-forming monomer by known radical polymerization. When the rubber elastic material constituting the core layer is obtained as an emulsion, it is preferable to polymerize the intermediate layer-forming monomer by emulsion polymerization.

[0135] The shell layer can be formed by polymerizing the shell layer-forming monomer by known radical polymerization. When a core layer, or a polymer particle precursor composed of a core layer coated with an intermediate layer, is obtained as an emulsion, the polymerization of the shell layer-forming monomer is preferably carried out by emulsion polymerization, and can be produced, for example, according to the method described in International Publication No. 2005 / 028546.

[0136] Examples of emulsifiers (dispersants) that can be used in emulsion polymerization include various acids such as alkyl or aryl sulfonic acids, alkyl or aryl ether sulfonic acids, alkyl or aryl sulfuric acids, alkyl or aryl sulfuric acids, alkyl or aryl sulfuric acids, alkyl or aryl ether sulfuric acids, alkyl or aryl substituted phosphoric acids, alkyl or aryl substituted phosphoric acids, N-alkyl or aryl sarcosinic acids, alkyl or aryl carboxylic acids, alkyl or aryl ether carboxylic acids, alkali metal salts or ammonium salts of these acids, anionic emulsifiers (dispersants) such as alkyl or aryl substituted polyethylene glycol, and dispersants such as polyvinyl alcohol, alkyl substituted cellulose, polyvinylpyrrolidone, and polyacrylic acid derivatives. These emulsifiers (dispersants) may be used individually or in combination of two or more.

[0137] It is preferable to use as little emulsifier (dispersant) as possible, as long as it does not impair the dispersion stability of the polymer particles in the aqueous latex. Furthermore, the higher the water solubility of the emulsifier (dispersant), the better. High water solubility makes it easier to wash away the emulsifier (dispersant) with water, and thus easily prevents adverse effects on the final cured product.

[0138] When employing emulsion polymerization, known initiators, namely 2,2'-azobisisobutyronitrile, hydrogen peroxide, potassium persulfate, and ammonium persulfate, can be used as thermal decomposition initiators.

[0139] In addition, redox initiators can be used in combination with peroxides such as organic peroxides including t-butyl peroxyisopropyl carbonate, paramentane hydroperoxide, cumene hydroperoxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and t-hexyl peroxide; and inorganic peroxides including hydrogen peroxide, potassium persulfate, and ammonium persulfate, along with, if necessary, reducing agents such as sodium formaldehyde sulfoxylate and glucose, and, if necessary, transition metal salts such as iron(II) sulfate, and, if further necessary, chelating agents such as disodium ethylenediaminetetraacetate, and, if further necessary, phosphorus-containing compounds such as sodium pyrophosphate.

[0140] When a redox-type initiator system is used, polymerization can be carried out even at low temperatures in which the peroxide does not substantially decompose thermally, which is preferable as it allows the polymerization temperature to be set over a wide range. In particular, it is preferable to use organic peroxides such as cumene hydroperoxide, dicumyl peroxide, and t-butyl hydroperoxide as redox-type initiators. The amount of the initiator used, and when a redox-type initiator is used, the amounts of the reducing agent, transition metal salt, chelating agent, etc. can be used within known ranges. Furthermore, when polymerizing monomers having two or more radically polymerizable double bonds, known chain transfer agents can be used within known ranges. Surfactants can also be used in addition, but this is also within known ranges.

[0141] The polymerization conditions, such as polymerization temperature, pressure, and deoxygenation, can be those within the known range. Furthermore, the polymerization of the intermediate layer-forming monomer may be carried out in one stage or in two or more stages. For example, methods such as adding the intermediate layer-forming monomer to the emulsion of the rubber elastic material constituting the elastic core layer all at once, or adding it continuously, or adding the emulsion of the rubber elastic material constituting the elastic core layer to a reactor that has already been charged with the intermediate layer-forming monomer before polymerization can be employed.

[0142] (B) When core-shell polymer particles are used as component, the amount of core-shell polymer particles in the curable resin composition is preferably 1 to 100 parts by mass, more preferably 5 to 90 parts by mass, even more preferably 10 to 80 parts by mass, even more preferably 15 to 70 parts by mass, and particularly preferably 20 to 60 parts by mass, based on a balance between the ease of handling of the resulting curable resin composition and the toughness improvement effect of the resulting cured product.

[0143] [1.3. Aluminum(C) Oxide] A curable resin composition according to one embodiment of the present invention contains, as component (C), aluminum oxide having an average particle size of 0.3 μm to 10.0 μm in the first component and / or the second component. When a curable resin composition according to one embodiment of the present invention contains component (C) having the above average particle size, the curable resin composition has the advantage of being low viscosity and the resulting cured product having excellent thermal conductivity. In this specification, aluminum oxide with an average particle size of less than 0.3 μm and aluminum oxide with an average particle size of more than 10.0 μm are not considered to be component (C) (i.e., aluminum oxide (C)).

[0144] In one embodiment of the present invention, the total mass of aluminum oxide (C) relative to the total mass (100% by mass) of the curable resin composition is 25% to 90% by mass, preferably 27% to 88% by mass, more preferably 29% to 86% by mass, even more preferably 31% to 84% by mass, and particularly preferably 33% to 84% by mass, from the viewpoint of improving the properties of the resulting cured product (thermal conductivity and elongation of the cured product) and improving the workability of the curable resin composition before curing (reducing the viscosity of the curable resin composition).

[0145] Component (C) may be contained in the first component only, in the second component only, or in both the first and second components. From the viewpoint of incorporating a large amount of component (C) into the curable resin composition, it is preferable that component (C) be contained in at least the first component, and more preferably in both the first and second components.

[0146] Aluminum oxide is a white powder crystalline substance with the chemical formula Al2O3, also known as alumina. Aluminum oxide is generally produced by heat-treating aluminum hydroxide.

[0147] Component (C) may be coupled to improve adhesion with component (A). This improves the physical properties of the resulting cured product, such as elongation, impact resistance, strength, and water resistance. The coupling agents are not particularly limited, but examples include silane-based coupling agents, chromium-based coupling agents, titanium-based coupling agents, aluminum-based coupling agents, and zirconium-based coupling agents. Among these, silane-based coupling agents are preferred, and epoxy silane coupling agents are more preferred. The coupling agents may be used alone or in combination of two or more types.

[0148] Aluminum oxide products exist with various average particle sizes. In one embodiment of the present invention, the average particle size of component (C) is preferably 0.3 μm to 10.0 μm, more preferably 0.4 μm to 9.0 μm, more preferably 0.6 μm to 8.0 μm, even more preferably 0.8 μm to 7.0 μm, and particularly preferably 1.0 μm to 6.0 μm, from the viewpoint of providing a low viscosity curable resin composition. Component (C) may be a single type of aluminum oxide with the same average particle size, or two or more types with different average particle sizes may be used in combination.

[0149] The curable resin composition may contain aluminum oxide with an average particle diameter of less than 0.3 μm and aluminum oxide with an average particle diameter of more than 10.0 μm, as long as the curing according to one embodiment of the present invention is not impaired. Since a low viscosity curable resin composition can be provided, it is preferable that the content of aluminum oxide with an average particle diameter of more than 10.0 μm in the curable resin composition is low. For example, the content of aluminum oxide with an average particle diameter of more than 10.0 μm in the curable resin composition is preferably 5% by mass or less, more preferably 3% by mass or less, more preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less, per 100% by mass of the curable resin composition. Most preferably, the content of aluminum oxide with an average particle diameter of more than 10.0 μm in the curable resin composition is 0% by mass per 100% by mass of the curable resin composition, that is, it is most preferable that the curable resin composition does not contain aluminum oxide with an average particle diameter of more than 10.0 μm.

[0150] In this specification, the average particle diameter of component (C) can be determined from measurements using a laser scattering particle size analyzer, and is the particle diameter (Dp50) corresponding to an integrated particle size distribution of 50% by volume.

[0151] When using multiple types of (C) components with different average particle sizes, the average particle size of the entire (C) component can be calculated by weighting the values ​​obtained by multiplying the mass percentage of each (C) component relative to the total amount of (C) components by their respective average particle size.

[0152] The content (amount) of aluminum oxide (C) per 100 parts by mass of epoxy resin (A) is not particularly limited, but from the viewpoint of improving the properties of the resulting cured product (thermal conductivity and elongation of the cured product) and improving the workability of the curable resin composition before curing (reducing the viscosity of the curable resin composition), it is preferably 200 parts by mass or more and 1800 parts by mass or less, more preferably 250 parts by mass or more and 1600 parts by mass or less, even more preferably 300 parts by mass or more and 1500 parts by mass or less, and particularly preferably 350 parts by mass or more and 1400 parts by mass or less.

[0153] As described above, polymer particles (B) and aluminum oxide (C) having a core-shell structure are preferably contained in the first and / or second component, respectively. In this case, the polymer particles (B) and aluminum oxide (C) may or may not be contained in the same component, but when component (B) and component (C) are included, it is preferable that component (B) and component (C) are included as the first component and component (C) is included as the second component.

[0154] [1.4. Epoxy hardener (D)] A curable resin composition according to one embodiment of the present invention contains an epoxy curing agent as component (D) in the second component.

[0155] Component (D) is a compound (including oligomers or polymers) containing active hydrogen groups that can react with epoxy resin (A) to form crosslinks even at low temperatures such as room temperature.

[0156] The epoxy curing agent (D) is reactive with epoxy groups at around room temperature (e.g., between 5°C and 50°C). Compared to epoxy curing agents for heat curing, epoxy curing agent (D) is reactive with epoxy groups at lower temperatures. When used in combination with polymer particles (B) and the compound (G) described later, epoxy curing agent (D) has the effect of achieving both excellent rapid curing and good adhesive strength without requiring heat treatment at high temperatures above 50°C.

[0157] The epoxy curing agent (D) according to one embodiment of the present invention preferably comprises one or more amine-based curing agents selected from the group consisting of (a) aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, and (b) one or more amine-terminated butadiene nitrile rubbers selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers.

[0158] In one embodiment of the present invention, the epoxy curing agent (D) more preferably comprises (i) an amine compound (D1) having an active hydrogen equivalent of 300 g / eq to 1000 g / eq, and (ii) an amine compound (D2) having an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq. By using a combination of an amine compound (D1) having an active hydrogen equivalent of 300 g / eq to 1000 g / eq and an amine compound (D2) having an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq, a cured product with high elongation and higher strength can be obtained.

[0159] Here, the active hydrogen equivalent (g / eq) is the number of grams of an amine compound containing one equivalent of active hydrogen from an amino group. In other words, it is the value obtained by dividing the molecular weight of the amine compound by the number of active hydrogens from amino groups in one molecule of the amine compound.

[0160] Examples of the aliphatic amines include linear aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, diethylaminopropylamine, and hexamethylenediamine, as well as fatty aromatic amines such as metaxylenediamine. Among these, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, diethylaminopropylamine, hexamethylenediamine, and metaxylenediamine are included in the amine compounds (D2) with an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq.

[0161] Examples of the aforementioned alicyclic amines include N-aminoethylpiberazine, bis(4-amino-3-methylcyclohexyl)methane, mensendiamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane (a type of spiroacetal diamine), norbornanediamine, bis(aminomethyl)tricyclodecane, and 1,3-bisaminomethylcyclohexane. Among these, N-aminoethylpiberazine, bis(4-amino-3-methylcyclohexyl)methane, mensendiamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, norbornanediamine, bis(aminomethyl)tricyclodecane, and 1,3-bisaminomethylcyclohexane are included in the amine compounds (D2) with an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq.

[0162] The aforementioned amide amines are compounds produced by the condensation of a dimer of tall oil fatty acid (dimer acid) with a polyamine such as triethylenetetramine or tetraethylenepentamine. Commercially available amide amines include Versamid 140 and Versamid 115. Among these, Versamid 140 and Versamid 115 are included in the amine compounds (D2) with an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq.

[0163] The amine-terminated polyethers include a polyether backbone and, on average, have 1 to 4 (more preferably 1.5 to 3) amino groups and / or imino groups per molecule. Examples include poly(oxypropylene)monoamine, poly(oxypropylene)diamine, poly(oxypropylene)triamine, and poly(oxypropylene)tetraamine. Commercially available amine-terminated polyethers include Jeffamine D-230 (poly(oxypropylene)diamine), Jeffamine D-400 (poly(oxypropylene)diamine), Jeffamine D-2000 (poly(oxypropylene)diamine), Jeffamine D-4000 (poly(oxypropylene)diamine), and Jeffamine T-5000 (poly(oxypropylene)triamine) manufactured by Huntsman. Among these, Jeffamine D-230 and Jeffamine D-400 are included in amine compounds (D2) with an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq, while Jeffamine D-2000, Jeffamine D-4000, and Jeffamine T-5000 are included in amine compounds (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq.

[0164] The amine-terminated butadiene nitrile rubber is a polybutadiene / acrylonitrile copolymer having, on average, 1 to 4 (more preferably 1.5 to 3) amino groups and / or imino groups per molecule, and having a main chain acrylonitrile monomer content of 5% to 40% by mass (more preferably 10% to 35% by mass, and even more preferably 15% to 30% by mass). Examples of commercially available amine-terminated rubbers include Hypro 1300X16 ATBN manufactured by CVC. Among these, Hypro 1300X16 ATBN is included in the amine compound (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq.

[0165] Examples of modified amine curing agents include (i) polyamine epoxy resin adducts, which are reaction products of various polyamines such as the aliphatic amines and alicyclic amines mentioned above with less than an equal amount of epoxy resin, and (ii) ketimines, which are dehydration reaction products of polyamines with ketones such as methyl ethyl ketone and isobutyl methyl ketone. Among these, modified aliphatic amines such as tetraethylenepentamine epoxy resin adducts and hexamethylenediamine epoxy resin adducts; modified alicyclic amines such as isophoronediamine epoxy resin adducts and 1,3-bisaminomethylcyclohexane epoxy resin adducts; modified amide amines such as Versamid 140 epoxy resin adducts; and modified amine-terminated polyethers such as Jeffamine D-230 epoxy resin adducts are included in the amine compounds (D2) with an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq. Furthermore, modified amine-terminated polyethers such as the epoxy resin adduct of Jeffamine D-2000, and modified amine-terminated butadiene nitrile rubbers such as the epoxy resin adduct of Hypro 1300X16 ATBN are included in the amine compound (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq.

[0166] Alternatively, the epoxy curing agent (D) in one embodiment of the present invention may also preferably include (i) one or more amine compounds selected from the group consisting of amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, and (ii) one or more amine compounds selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, and modified amine-terminated polyethers. With the above combination, a cured product with high elongation and higher strength can be obtained.

[0167] The epoxy curing agent (D) according to one embodiment of the present invention preferably contains, among amine-based curing agents, one or more selected from the group consisting of amine-terminated polyethers and amine-terminated butadiene nitrile rubbers, from the viewpoint of the elongation and impact resistance of the resulting cured product, and (b) it is even more preferable to contain amine-terminated butadiene nitrile rubber from the viewpoint of curability. The epoxy curing agent (D) according to one embodiment of the present invention is preferably, among amine-based curing agents, (a) from the viewpoint of the adhesive strength of the resulting cured product, (a-1) contains one or more selected from the group consisting of alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, (a-2) more preferably contains one or more selected from the group consisting of alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, and (b) from the viewpoint of curability, (b-1) more preferably contains one or more selected from the group consisting of alicyclic amines and amine-terminated butadiene nitrile rubbers, and (b-2) more preferably contains one or more selected from the group consisting of alicyclic amines and amine-terminated butadiene nitrile rubbers. The epoxy curing agent (D) according to one embodiment of the present invention more preferably contains at least one selected from the group consisting of alicyclic amines, amine-terminated butadiene nitrile rubbers, modified alicyclic amines, and modified amine-terminated butadiene nitrile rubbers, and even more preferably contains at least one selected from the group consisting of alicyclic amines, amine-terminated butadiene nitrile rubbers, modified alicyclic amines, and modified amine-terminated butadiene nitrile rubbers, from the viewpoint of the adhesive strength and curability of the resulting cured product.

[0168] The ratio of the number of moles of epoxy groups in the epoxy resin (A) to the number of moles of active hydrogen groups in the epoxy curing agent (D) (number of moles of epoxy groups / number of moles of active hydrogen groups) is preferably 0.5 to 1.5, more preferably 1.1 to 1.5, even more preferably 1.1 to 1.4, and particularly preferably 1.2 to 1.4, from the viewpoint of the rapid curing properties of the curable resin composition and the adhesive strength, elongation, and impact resistance of the resulting cured product.

[0169] The content (amount) of the epoxy curing agent (D) per 100 parts by mass of the epoxy resin (A) is preferably 15 parts by mass or more and 300 parts by mass or less, more preferably 20 parts by mass or more and 280 parts by mass or less, even more preferably 30 parts by mass or more and 260 parts by mass or less, and particularly preferably 40 parts by mass or more and 240 parts by mass or less, from the viewpoint of achieving a balance between adhesive strength, elongation and impact resistance of the resulting cured product, and ease of mixing when mixing the first and second components. Component (D) may be used alone or two or more may be used in combination.

[0170] This curable resin composition may or may not contain aromatic amines. It is preferable that this curable resin composition substantially contains aromatic amines, as this results in superior elongation properties of the resulting cured product upon heating. In this specification, "substantially free of aromatic amines" means that the aromatic amine content in 100 parts by mass of the curable resin composition is 1000 ppm or less. Examples of aromatic amines include metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0171] Component (D) may further contain a mercaptan-based curing agent, which is a curing agent capable of reacting with epoxy resin (A) to form crosslinks even at low temperatures such as room temperature. More specifically, examples of the mercaptan-based curing agent include pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinan-2,4,6-trione, trimethylolpropane tris(3-mercaptobutyrate), thiol-terminated polyethers, and thiol-terminated polysulfides.

[0172] In addition to epoxy curing agents containing active hydrogen groups that can react with epoxy resins at low temperatures (such as the amine-based curing agents and mercaptan-based curing agents mentioned above), epoxy curing agents that exhibit activity at high temperatures can be included in this curable resin composition, provided that they do not impair the curing rate. Examples of epoxy curing agents that exhibit activity at high temperatures include acid anhydride-based curing agents, boron trifluoride-amine complexes, dicyandiamides, and organic acid hydrazides.

[0173] Although the aforementioned acid anhydride-based curing agent requires higher temperatures compared to amine-based curing agents, it has a longer pot life, and the cured product has a good balance of physical properties such as electrical, chemical, and mechanical properties. More specifically, examples of acid anhydride-based curing agents include polysebacic acid polyanhydride, polyazelaic acid polyanhydride, succinic anhydride, citraconic acid anhydride, itaconic acid anhydride, alkenyl-substituted succinic acid anhydride, dodecenyl succinic acid anhydride, maleic anhydride, tricarbaryl anhydride, nadoic acid anhydride, methylnadoic acid anhydride, linoleic acid adducts with maleic anhydride, alkylated-terminated alkylene tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic acid dianhydride, trimellitic acid anhydride, phthalic anhydride, tetrachlorophthalic acid anhydride, tetrabromophthalic acid anhydride, dichloromaleic acid anhydride, chloronadoic acid anhydride, and chlorendic acid anhydride, as well as maleic anhydride-grafted polybutadiene.

[0174] More specifically, examples of the boron trifluoride-amine complexes include boron trifluoride-monoethylamine, boron trifluoride-piperidine, boron trifluoride-triethylamine, and boron trifluoride-aniline.

[0175] More specifically, examples of the aforementioned organic acid hydrazides include adipic acid dihydrazide, stearate dihydrazide, isophthalic acid dihydrazide, and semicarbazide.

[0176] In the curable resin composition, the content (amount blended) of epoxy curing agents other than component (D) that exhibit activity at high temperatures is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, even more preferably 1 part by mass or more and 15 parts by mass or less, and particularly preferably 2 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the epoxy resin (A).

[0177] [1.5. Aluminum(E) hydroxide] The curable resin composition according to one embodiment of the present invention more preferably contains aluminum hydroxide (E) in the first component and / or the second component. In this specification, "aluminum hydroxide (E)" may also be referred to as "component (E)". When the curable resin composition contains component (E), the resulting cured product has the advantage of excellent thermal conductivity and flame retardancy.

[0178] Aluminum hydroxide is a white powder crystal represented by the chemical formula Al(OH)3 or Al2O3·3H2O, and is generally produced by the Bayer process using bauxite as a raw material.

[0179] Component (E) may be contained in the first component only, in the second component only, or in both the first and second components. From the viewpoint of incorporating a large amount of component (E) into the curable resin composition, it is preferable that component (E) be contained in at least the first component, and more preferably in both the first and second components.

[0180] Component (E) may be coupled to improve its adhesion to component (A). This improves the physical properties of the resulting cured product, such as elongation, impact resistance, strength, and water resistance. The coupling agents are not particularly limited, but examples include silane-based coupling agents, chromium-based coupling agents, titanium-based coupling agents, aluminum-based coupling agents, and zirconium-based coupling agents. Among these, silane-based coupling agents are preferred, and epoxy silane coupling agents are more preferred. The coupling agents may be used alone or in combination of two or more types.

[0181] Aluminum hydroxide exists in products with various average particle sizes depending on the classification. In one embodiment of the present invention, the average particle size of component (E) is not particularly limited, but from the viewpoint of achieving both elongation, impact resistance and adhesive strength of the resulting cured product, and from the viewpoint of suppressing the settling of component (E) over time in the curable resin composition before curing, it is preferably 11 μm to 200 μm, preferably 12 μm to 150 μm, more preferably 13 μm to 100 μm, even more preferably 15 μm to 50 μm, and particularly preferably 17 μm to 30 μm.

[0182] In this specification, the average particle diameter of component (E) can be determined from measurements using a laser scattering particle size analyzer, and is the particle diameter (Dp50) corresponding to an integrated particle size distribution of 50% by volume.

[0183] When using multiple types of (E) components with different average particle sizes, the average particle size of the entire (E) component can be calculated by taking a weighted average of the values ​​obtained by multiplying the mass percentage of each (E) component relative to the total amount of (E) components by their respective average particle size.

[0184] In one embodiment of the present invention, the total mass of aluminum hydroxide (E) relative to the total mass of the curable resin composition is not particularly limited, but from the viewpoint of improving the properties of the resulting cured product (thermal conductivity and elongation of the cured product) and improving the workability of the curable resin composition before curing (reducing the viscosity of the curable resin composition), it is 0% to 68% by mass, preferably 10% to 66% by mass, more preferably 15% to 64% by mass, even more preferably 20% to 62% by mass, and particularly preferably 25% to 60% by mass.

[0185] The content (amount) of aluminum hydroxide (E) per 100 parts by mass of epoxy resin (A) is not particularly limited, but from the viewpoint of improving the properties of the resulting cured product (thermal conductivity and elongation of the cured product) and improving the workability of the curable resin composition before curing (reducing the viscosity of the curable resin composition), it is preferably 0 parts by mass or more and 1000 parts by mass or less, more preferably 100 parts by mass or more and 950 parts by mass or less, even more preferably 200 parts by mass or more and 900 parts by mass or less, and particularly preferably 250 parts by mass or more and 850 parts by mass or less. Component (E) may be used alone or two or more may be used in combination.

[0186] As described above, polymer particles (B) and aluminum hydroxide (E) having a core-shell structure are preferably contained in the first and / or second component, respectively. In this case, the polymer particles (B) and aluminum hydroxide (E) may or may not be contained in the same component, but when component (B) and component (E) are included, it is preferable that component (B) and component (E) are included as the first component and component (E) is included as the second component.

[0187] By using aluminum oxide (C) and aluminum hydroxide (E) in combination as thermally conductive fillers, flame retardancy can be improved without impairing thermal conductivity.

[0188] [1.6. Other Ingredients] [1.6.1] Thermally conductive fillers The curable resin composition according to one embodiment of the present invention may contain thermally conductive fillers other than aluminum oxide (C) and aluminum hydroxide (E). Examples of such thermally conductive fillers include silica, aluminum oxide with an average particle diameter of less than 0.3 μm, aluminum oxide with an average particle diameter of more than 10.0 μm, aluminum nitride, boron nitride, silicon nitride, ZnO, SiC, and BeO.

[0189] The content of thermally conductive fillers other than aluminum oxide (C) and aluminum hydroxide (E) in the curable resin composition is preferably 1 to 300 parts by mass, more preferably 2 to 200 parts by mass, and particularly preferably 5 to 100 parts by mass, per 100 parts by mass of epoxy resin (A).

[0190] [1.6.2] Flame retardants The curable resin composition according to one embodiment of the present invention may contain flame retardants other than aluminum hydroxide. Examples include magnesium hydroxide, ammonium polyphosphate, tricresyl phosphate, triethyl phosphate, triphenyl phosphate, tris(chloropropyl) phosphate, dimethyl methylphosphonate, brominated polyether polyol, ammonium carbonate, and melamine cyanurate.

[0191] The content of flame retardants other than aluminum hydroxide in the curable resin composition is preferably 1 to 100 parts by mass, more preferably 2 to 70 parts by mass, and particularly preferably 5 to 50 parts by mass, per 100 parts by mass of epoxy resin (A).

[0192] [1.6.3] Inorganic filler The components (C) and (E) described above can also function as inorganic fillers in the curable resin composition. The curable resin composition may contain inorganic fillers other than aluminum oxide (C) and aluminum hydroxide (E). Examples of inorganic fillers other than components (C) and (E) include aluminum oxide with an average particle size of less than 0.3 μm, aluminum oxide with an average particle size of more than 10.0 μm, silicic acid and / or silicates. Specific examples of silicates include dry silica, wet silica, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, talc, and the like.

[0193] The aforementioned dry silica is also called fumed silica, and includes hydrophilic fumed silica with no surface treatment and hydrophobic fumed silica produced by chemically treating the silanol group portion of hydrophilic fumed silica with silane or siloxane. Hydrophobic fumed silica is preferred in terms of its dispersibility in components (A) and (D). Fumed silica can impart thixotropy to the first and second components, exhibiting a sagging prevention effect.

[0194] Other specific examples of inorganic fillers other than components (C) and (E) include reinforcing fillers such as dolomite and carbon black; heavy calcium carbonate, colloidal calcium carbonate, wollastonite, magnesium carbonate, titanium dioxide, ferric oxide, aluminum powder, zinc oxide, activated zinc oxide, etc.

[0195] It is preferable that inorganic fillers other than components (C) and (E) are surface-treated with a surface treatment agent. Surface treatment improves the dispersibility of inorganic fillers other than component (C) in the curable resin composition, and as a result, various physical properties of the resulting cured product are improved.

[0196] Inorganic fillers other than components (C) and (E) may be used individually or in combination of two or more types.

[0197] The content (amount used) of inorganic fillers other than components (C) and (E) is preferably 1 to 100 parts by mass, more preferably 2 to 70 parts by mass, even more preferably 5 to 40 parts by mass, and particularly preferably 7 to 20 parts by mass, per 100 parts by mass of component (A).

[0198] [1.6.4] Epoxy curing accelerator (F) A curable resin composition according to one embodiment of the present invention may contain an epoxy curing accelerator (F) in the first component and / or the second component. In this specification, the "epoxy curing accelerator (F)" may also be referred to as "component (F)". Component (F) is a compound that does not readily react with epoxy resin (A) to form crosslinks, but can accelerate the curing reaction between epoxy resin (A) and epoxy curing agent (D). In particular, component (F) is preferably one that exhibits a significant acceleration effect when used in combination with an epoxy curing agent that has high curability at room temperature, such as aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubber, or modified versions thereof.

[0199] Component (F) may be contained in only the first component, only the second component, or in both the first and second components. From the viewpoint of the storage stability of the curable resin composition, it is preferable that component (F) be contained only in the second component.

[0200] (F) Examples of components include imidazoles such as C1-C12 alkyleneimidazole, N-arylimidazole, 2-methylimidazole, 2-ethyl-2-methylimidazole, N-butylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, and addition products of epoxy resin and imidazole; tertiary amines such as N,N-dimethylpiperazine, diazabicycloundecene, diazabicyclononene, triethylenediamine, benzyldimethylamine, and triethylamine; phenols such as 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol incorporated into a poly(p-vinylphenol) matrix, pt-butylphenol, phenol, 4-methoxyphenol, resorcinol, catechol, and 4-t-butylcatechol; and so on. Among these, phenols are preferred from the viewpoint of improving curability, and divalent phenols such as resorcinol, catechol, and 4-t-butylcatechol are more preferred. Component (F) may be used alone or in combination of two or more.

[0201] The amount of epoxy curing accelerator (F) blended with 100 parts by mass of epoxy resin (A) is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 20 parts by mass or less, even more preferably 2 parts by mass or more and 15 parts by mass or less, and particularly preferably 3 parts by mass or more and 10 parts by mass or less, from the viewpoint of improving curability and storage stability.

[0202] [1.6.5] Silane coupling agent (G) A curable resin composition according to one embodiment of the present invention may contain a silane coupling agent (G) in the first component and / or the second component. In this specification, "silane coupling agent (G)" may also be referred to as "component (G)".

[0203] If the curable resin composition contains component (G), component (G) acts as an adhesive aid that connects the adherend surface, such as glass and metal, with the curable resin composition.

[0204] Specific examples of silane coupling agents (G) include isocyanate group-containing silanes such as γ-isocyanatetopropyltrimethoxysilane, γ-isocyanatetopropyltriethoxysilane, and γ-isocyanatetopropylmethyldimethoxysilane; amino group-containing silanes such as γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; and N-(1,3-dimethylbutylidene)- Examples include ketimine-type silanes such as 3-(triethoxysilyl)-1-propanamine; mercapto-group-containing silanes such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldimethoxysilane; epoxy-group-containing silanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane; and isocyanurate silanes such as tris(3-trimethoxysilylpropyl)isocyanurate. Among these, epoxy-group-containing silanes are preferred from the viewpoint of adhesive strength of the cured product obtained.

[0205] In this specification, silane coupling agents (G) that contain epoxy groups may be referred to as "epoxysilane coupling agent (G1)".

[0206] Component (G) may be contained in the first component only, in the second component only, or in both the first and second components. From the viewpoint of the storage stability of the curable resin composition, (a) if component (F) is one or more selected from the group consisting of isocyanate group-containing silanes, epoxy group-containing silanes (epoxysilane coupling agent (G1)), and isocyanurate silanes, it is preferable to contain component (G) in the first component only, and (b) if component (G) is one or more selected from the group consisting of amino group-containing silanes, ketimine-type silanes, and mercapto group-containing silanes, it is preferable to contain component (G) in the second component only.

[0207] The amount of the silane coupling agent (G) blended with 100 parts by mass of the epoxy resin (A) is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, even more preferably 2 parts by mass or more and 10 parts by mass or less, and particularly preferably 3 parts by mass or more and 7 parts by mass or less, from the viewpoint of improving adhesion and storage stability.

[0208] Since the resulting curable resin composition has excellent storage properties and the cured product obtained by curing the curable resin composition has excellent adhesive strength, it is more preferable that the curable resin composition contains an epoxysilane coupling agent (G1) as component (G) in its first component.

[0209] [1.6.6] Reinforcement Agent The curable resin composition may optionally contain reinforcers such as blocked urethane or epoxy unmodified rubber polymers to further improve properties such as toughness, elongation, impact resistance, adhesive strength (shear adhesion (shear bond strength)), and peel adhesion. The reinforcers may be used alone or in combination of two or more types.

[0210] (Blocked urethane) Blocked urethane is an elastomer-type compound containing urethane groups and / or urea groups, and having isocyanate groups at its terminals, wherein all or part of these terminal isocyanate groups are capped with various blocking agents having active hydrogen groups. Compounds in which all of the terminal isocyanate groups are capped with a blocking agent are particularly preferred. Such compounds can be obtained, for example, by reacting an excess polyisocyanate compound with an organic polymer having active hydrogen-containing groups at its terminals to form a polymer (urethane prepolymer) having urethane groups and / or urea groups in the main chain and isocyanate groups at its terminals, and then simultaneously capping all or part of the isocyanate groups with a blocking agent having active hydrogen groups.

[0211] Specific examples of blocked urethanes include the compounds described in International Publication No. 2016 / 163491.

[0212] The number-average molecular weight of the blocked urethane is preferably 2,000 to 40,000, more preferably 3,000 to 30,000, and particularly preferably 4,000 to 20,000, as measured by GPC in terms of polystyrene-equivalent molecular weight. The molecular weight distribution (ratio of mass-average molecular weight to number-average molecular weight) is preferably 1 to 4, more preferably 1.2 to 3, and particularly preferably 1.5 to 2.5.

[0213] Blocked urethane can be used alone or in combination of two or more types.

[0214] The amount of blocked urethane is preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, and particularly preferably 5 to 30 parts by mass, per 100 parts by mass of epoxy resin (A). An amount of 1 part by mass or more provides good improvements in toughness, elongation, impact resistance, and adhesion, while an amount of 50 parts by mass or less results in a higher elastic modulus of the resulting cured product.

[0215] [1.6.7] Epoxy unmodified rubber polymer The rubber polymer may be included (blended) in the curable resin composition as needed, without being reacted with the epoxy resin and remaining in its unmodified state.

[0216] Examples of the aforementioned rubber polymers include acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR), hydrogenated nitrile rubber (HNBR), ethylene propylene rubber (EPDM), acrylic rubber (ACM), butyl rubber (IIR), butadiene rubber, and polyoxyalkylenes such as polypropylene oxide, polyethylene oxide, and polytetramethylene oxide. The rubber polymers are preferably those having reactive groups such as amino groups, hydroxyl groups, or carboxyl groups at their ends. Among these, NBR and polyoxyalkylenes are preferred from the viewpoint of the adhesion of the resulting curable resin composition, as well as the elongation and impact-peel adhesion of the cured product. NBR is more preferred, and carboxyl-terminated NBR (CTBN) is particularly preferred.

[0217] The glass transition temperature (Tg) of the rubber polymer is not particularly limited, but is preferably -25°C or lower, more preferably -35°C or lower, even more preferably -40°C or lower, and particularly preferably -50°C or lower.

[0218] The number-average molecular weight of the rubber polymer is preferably 1,500 to 40,000, more preferably 3,000 to 30,000, and particularly preferably 4,000 to 20,000, as measured by GPC in terms of polystyrene-equivalent molecular weight. The molecular weight distribution (ratio of mass-average molecular weight to number-average molecular weight) is preferably 1 to 4, more preferably 1.2 to 3, and particularly preferably 1.5 to 2.5.

[0219] Rubber polymers can be used individually or in combination of two or more types.

[0220] The amount of rubber polymer is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and particularly preferably 5 to 10 parts by mass, per 100 parts by mass of epoxy resin (A). An amount of 1 part by mass or more provides good improvements in toughness, elongation, impact resistance, and adhesion, while an amount of 50 parts by mass or less results in a higher elastic modulus of the resulting cured product.

[0221] [1.6.8] Monoepoxy The curable resin composition may optionally contain a monoepoxide. The monoepoxide can function as a reactive diluent. Specific examples of monoepoxides include aliphatic glycidyl ethers such as butyl glycidyl ether, aromatic glycidyl ethers such as phenyl glycidyl ether and cresyl glycidyl ether, ethers consisting of an alkyl group with 8 to 10 carbon atoms and a glycidyl group such as 2-ethylhexyl glycidyl ether, ethers consisting of a phenyl group with 6 to 12 carbon atoms and a glycidyl group that can be substituted with an alkyl group with 2 to 8 carbon atoms such as p-tert butylphenyl glycidyl ether, ethers consisting of an alkyl group with 12 to 14 carbon atoms and a glycidyl group such as dodecyl glycidyl ether; aliphatic glycidyl esters such as glycidyl (meth)acrylate and glycidyl maleate; glycidyl esters of aliphatic carboxylic acids with 8 to 12 carbon atoms such as glycidyl versatate, glycidyl neodecanoate, and glycidyl laurate; and pt-butylbenzoate glycidyl ester.

[0222] When using monoepoxide, the amount of monoepoxide in the curable resin composition is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, and particularly preferably 1 to 5 parts by mass, per 100 parts by mass of component (A). A concentration of 0.1 parts by mass or more provides a good viscosity reduction effect, while a concentration of 20 parts by mass or less results in good physical properties such as adhesion.

[0223] [1.6.9] Other ingredients The curable resin composition may contain other additives as needed. Examples of other additives include radical-curable resins, thermal radical polymerization initiators, photocurable resins, photopolymerization initiators, azotype chemical foaming agents, expanding agents such as thermally expandable microballoons, fibrous pulps such as aramid pulp, colorants such as pigments and dyes, extender pigments, ultraviolet absorbers, antioxidants, stabilizers (gelling inhibitors), plasticizers, leveling agents, defoamers, antistatic agents, lubricants, viscosity reducers, low shrinkage agents, organic fillers, thermoplastic resins, desiccants, dispersants, and solvents.

[0224] In curable resin compositions, the "content" of each component may be interpreted as the "amount blended" of each component.

[0225] [1.7. Method for producing curable resin compositions] The method for producing the curable resin composition is not particularly limited. Below, as one embodiment of the curable resin composition, an example of a method for producing the curable resin composition X will be described, comprising a first component containing component (A), component (B), and component (C), and a second component containing component (D) and component (C).

[0226] The first component of the curable resin composition X includes an epoxy resin (A), which is a curable resin, and a composition containing core-shell polymer particles as component (B) (hereinafter also referred to as the "polymer particle-containing composition"). Preferably, the polymer particle-containing composition is a composition in which the core-shell polymer particles (B) are dispersed in a primary particle state.

[0227] Various methods can be used to obtain a composition (polymer particle-containing composition) in which core-shell polymer particles (B) are dispersed in component (A) in the form of primary particles. Examples of such methods include contacting core-shell polymer particles (B) obtained in an aqueous latex state with component (A) and then removing unwanted components such as water, or extracting the core-shell polymer particles (B) in an organic solvent, mixing the extracted core-shell polymer particles (B) with component (A), and then removing the organic solvent. However, it is preferable to use the method described in International Publication No. 2005 / 028546. A specific method for producing a polymer particle-containing composition preferably comprises, in order: a first step of mixing an aqueous latex containing core-shell polymer particles (B) (more specifically, a reaction mixture obtained after producing core-shell polymer particles (B) by emulsion polymerization) with an organic solvent having a solubility in water at 20°C of 5% by mass or more and 40% by mass or less, and then mixing the resulting mixture with excess water to aggregate the core-shell polymer particles (B); a second step of separating and recovering the aggregated core-shell polymer particles (B) from the liquid phase, and then mixing the resulting aggregate of core-shell polymer particles (B) again with the organic solvent to obtain an organic solvent dispersion of core-shell polymer particles (B); and a third step of further mixing the organic solvent dispersion with component (A), and then distilling off the organic solvent from the resulting mixture.

[0228] Component (A) is preferably liquid at 23°C, as this facilitates the third step. "Liquid at 23°C" means that its softening point is 23°C or lower, and that it exhibits fluidity at 23°C.

[0229] The first component of curable resin composition X can be obtained by mixing the composition obtained through the above process, in which core-shell polymer particles (B) are dispersed in component (A) in a primary particle state (polymer particle-containing composition), with component (C), and optionally additional components (A), (E), and other components (e.g., component (F) and / or component (G)) using a stirrer such as a planetary mixer. The second component of curable resin composition X can be obtained by mixing components (D), (C), and optionally components (B), (E), and other components (e.g., component (F) and / or component (G)) using a stirrer such as a planetary mixer.

[0230] In the above description, a method for producing a curable resin composition X was described in which a first component containing core-shell polymer particles (B) is prepared, and then the first component is mixed with a second component that may or may not contain core-shell polymer particles (B). However, one embodiment of the curable resin composition may be a curable resin composition Y comprising a first component containing components (A) and (C), and a second component containing components (D), (B), and (C). Such a curable resin composition Y can be produced by preparing a first component that does not contain core-shell polymer particles (B), and then mixing the first component with a second component that contains core-shell polymer particles (B).

[0231] As described above, it is preferable that the first component containing epoxy resin (A) and the second component containing epoxy curing agent (D) be prepared separately. It is preferable that the first and second components be mixed immediately before use (immediately before the bonding operation of the objects to be bonded, or immediately before the curing of the curable resin composition).

[0232] On the other hand, powdered core-shell polymer particles (B), obtained by solidifying them by methods such as salting out and then drying them, can be redispersed in component (A) or component (D) using a disperser with high mechanical shear force, such as a three-roll paint mill, roll mill, and kneader. In this case, applying mechanical shear force at a high temperature enables efficient redispersion of component (B). The temperature when redispersing component (B) in component (A) or component (D) is preferably 50 to 200°C, more preferably 70 to 170°C, even more preferably 80 to 150°C, and particularly preferably 90 to 120°C.

[0233] [2. Cured product] A cured product can be obtained by uniformly mixing the first and second components of a curable resin composition using a static mixer or the like, and then curing the resulting mixture at the curing temperature described later. In the first component obtained by the method described above, it is considered that the core-shell polymer particles (B) are uniformly dispersed, and therefore, in a cured product obtained using such a first component, it is considered that the core-shell polymer particles (B) are uniformly dispersed.

[0234] A cured product obtained by curing a curable resin composition is also one embodiment of the present invention. The cured product according to one embodiment of the present invention has the advantage of excellent thermal conductivity (radiation performance) and elongation. The cured product according to one embodiment of the present invention also has the advantage of excellent adhesive strength and impact peel adhesion.

[0235] (Application method) The curable resin composition can be applied to a substrate by any method. According to a preferred embodiment, it can be applied at a low temperature of about room temperature, and can also be applied by heating if necessary.

[0236] The first and second components of the curable resin composition can be uniformly mixed in a static mixer connected to the tip of a quantitative dispensing device after being dispensed from the device, and then applied during application. Alternatively, the first and second components of the curable resin composition can be filled into each cartridge of a double-cartridge type caulking gun, to which a static mixer is connected, and then manually extruded for application. It can also be extruded onto the substrate in a bead, monofilament, or swirl pattern using a coating robot. The viscosity of the curable resin composition at the application temperature is not particularly limited, but is preferably around 150 to 600 Pa·s for the extrusion bead method, about 100 Pa·s for the swirl coating method, and about 20 to 400 Pa·s for the high-volume coating method using a high-speed flow device.

[0237] [3. Adhesives] Curable resin compositions are preferable to use as an adhesive material because the resulting cured product exhibits excellent adhesive strength and impact resistance. An adhesive containing a curable resin composition is also one embodiment of the present invention. The adhesive according to one embodiment of the present invention has low viscosity, and the adhesive layer (cured product) obtained by curing the adhesive has the advantage of excellent thermal conductivity (radiation performance) and elongation. The adhesive layer (cured product) obtained by curing the adhesive according to one embodiment of the present invention also has the advantage of excellent adhesive strength and impact-peel adhesion.

[0238] When using a curable resin composition as an adhesive to bond various substrates together, for example, it can be used to join metals such as aluminum plates and steel plates, wood, plastics, and glass. Examples of substrates include steel materials such as cold-rolled steel and hot-dip galvanized steel, aluminum materials such as aluminum and coated aluminum, general-purpose plastics, engineering plastics, composite materials such as CFRP and GFRP, and various other plastic substrates.

[0239] Furthermore, the cured product of the curable resin composition exhibits excellent thermal conductivity and flame retardancy. For this reason, the curable resin composition is preferably used as an adhesive for fixing EV battery cells to a module case. In other words, the adhesive according to one embodiment of the present invention is preferably an adhesive for secondary batteries. As for a method for manufacturing a battery module using an adhesive containing a curable resin composition, and the application site and method of the adhesive to the module, the method described in International Publication No. 2016 / 137303 can be cited.

[0240] Furthermore, the cured product of the curable resin composition exhibits excellent elongation and impact-peel adhesion. For this reason, the curable resin composition is preferably used as an adhesive for joining two or more substrates that constitute the body of a vehicle (for example, dissimilar materials such as steel materials to steel, aluminum materials to aluminum, or steel and aluminum). In other words, the adhesive according to one embodiment of the present invention is preferably an adhesive for vehicles.

[0241] [4. Laminates] Curable resin compositions have excellent adhesive properties. Therefore, curable resin compositions are preferably used as adhesives for bonding (joining) two substrates. The laminate obtained in this way comprises two substrates and an adhesive layer between the two substrates, formed by curing an adhesive containing the curable resin composition. This adhesive layer is also an embodiment of the present invention. A laminate according to an embodiment of the present invention can be obtained, for example, by the following method: (1) applying an adhesive containing the curable resin composition to one or both substrates; (2) bringing the substrates into contact with each other so that the adhesive is positioned between the two substrates to be joined; (3) curing the adhesive in that state to join the two substrates. The laminate according to an embodiment of the present invention obtained in this way is preferred because it exhibits high adhesive strength.

[0242] Curable resin compositions and adhesives containing such curable resin compositions are suitable for bonding dissimilar substrates with different coefficients of thermal expansion due to their excellent toughness.

[0243] Furthermore, the curable resin composition and the adhesive containing the curable resin composition can also be used for joining aerospace components, particularly exterior metal components.

[0244] (curing temperature) The curing temperature of the curable resin composition is not particularly limited, but from the viewpoint of being able to easily cure at or near room temperature, 5°C to 60°C is preferred, 10°C to 50°C is more preferred, 15°C to 40°C is even more preferred, and 20°C to 30°C is particularly preferred.

[0245] [5.Applications] Curable resin compositions are preferably used in applications such as structural adhesives for vehicles and aircraft, adhesives for secondary batteries such as EV battery cells, structural adhesives for wind power generation, paints, materials for laminating with glass fibers and / or carbon fibers to obtain composite materials, materials for printed circuit boards, solder resists, interlayer insulating films, build-up materials, adhesives for FPCs, electrical insulating materials such as encapsulants for electronic components such as semiconductors and LEDs, die bond materials, underfills, mounting materials for semiconductors (e.g., ACF, ACP, NCF, NCP, etc.), encapsulants for display devices (e.g., liquid crystal panels and OLED displays, etc.) and lighting equipment (e.g., OLED lighting, etc.), and composite materials for concrete repair. Curable resin compositions are particularly useful as adhesives for secondary batteries.

[0246] Generally, secondary batteries such as lithium-ion batteries are sensitive to heat and cannot be heat-cured; therefore, it is necessary to use a room-temperature curing two-component (or multi-component) adhesive rather than a heat-curing adhesive. Furthermore, secondary batteries such as lithium-ion batteries tend to accumulate heat during charging and discharging, so an adhesive with heat dissipation properties is required. This curable resin composition has excellent thermal conductivity after curing, making it particularly useful as an adhesive for secondary batteries such as lithium-ion batteries, where heat dissipation performance is required. In addition, this curable resin composition has excellent elongation after curing, making it particularly useful as an adhesive for vehicles, especially vehicles equipped with lithium-ion batteries, from the viewpoint of impact resistance against vibrations in vehicles.

[0247] When curable resin compositions are used in composite materials, they can be used in a wide range of molding methods without particular limitations. Specifically, they can be molded using known molding methods such as hand lay-up, spray-up, pultrusion, filament winding, matched die, prepreg, centrifugal molding, liquid molding, hot press, casting, injection molding, continuous lamination, resin transfer molding (RTM), vacuum bag molding, and cold press. Curable resin compositions are suitable as composite materials with glass fibers or carbon fibers, and as raw materials for BMC (bulk molding compound) and SMC (sheet molding compound). Furthermore, there are no particular restrictions on the application area, but specifically, it is suitable for artificial marble applications such as kitchen countertops, washbasins, bathtubs, and wall materials; resin concrete, tanks, pressure vessels, industrial pipes, factory piping, fittings, pipes, corrugated sheets, helmets, poles, wind turbine blades, piping for oil field pump extraction systems such as soccer rods and pumps; electrical components, automobile parts, railway vehicle parts, ship parts, aircraft parts, industrial machinery parts, construction materials, furniture, musical instruments and other structural components; and sheet materials such as decorative panels and decorative sheets. [Examples]

[0248] An embodiment of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0249] (Measurement of volume-average particle diameter of core-shell polymer particles) The volume-average particle diameters of polybutadiene rubber particles in the polybutadiene rubber latex described in the manufacturing example, and core-shell polymer particles (B) in the core-shell polymer latex, were measured using the following method. The volume-average particle diameter (Mv) of particles dispersed in aqueous latex was measured using a Microtrac UPA150 (manufactured by Nikkiso Co., Ltd.). Samples diluted with deionized water were used as measurement samples. The measurement was performed by inputting the refractive index of water and the refractive index of each polymer particle, adjusting the sample concentration so that the signal level was within the range of 0.6 to 0.8 with a measurement time of 600 seconds.

[0250] [Manufacturing Example 1: Preparation of Polybutadiene Rubber Latex (R-2) (Formation of Core Layer)] 200 parts by mass of water, 0.03 parts by mass of tripotassium phosphate, 0.002 parts by mass of disodium ethylenediaminetetraacetate (EDTA), 0.001 parts by mass of ferrous sulfate heptahydrate (FE), and 1.55 parts by mass of sodium dodecylbenzenesulfonate (SDBS) were added to a pressure polymerizer. After thoroughly purging the system with nitrogen while stirring the added components to remove oxygen, 100 parts by mass of butadiene (Bd) was added to the system and the temperature of the mixture was raised to 45°C. After raising the temperature, 0.03 parts by mass of paramenthane hydroperoxide (PHP) and then 0.10 parts by mass of sodium formaldehyde sulfoxylate (SFS) were added to the system to start polymerization. At 3 hours, 5 hours, and 7 hours after the start of polymerization, 0.025 parts by mass of PHP were added to the system. Furthermore, 0.0006 parts by mass of EDTA and 0.003 parts by mass of FE were added at 4, 6, and 8 hours after the start of polymerization. At 15 hours of polymerization, the polymerization was terminated by defoliation under reduced pressure to remove any monomers that were not used in polymerization. Through this procedure, polybutadiene rubber latex (R-1), mainly composed of polybutadiene rubber, was obtained. The volume-average particle size of the polybutadiene rubber particles contained in the obtained latex was 80 nm.

[0251] In a pressure polymerization reactor, 21 parts by mass of polybutadiene rubber latex (R-1) (including 7 parts by mass of polybutadiene rubber), 185 parts by mass of deionized water, 0.03 parts by mass of tripotassium phosphate, 0.002 parts by mass of EDTA, and 0.001 parts by mass of FE were added. After thoroughly purging with nitrogen while stirring the added components to remove oxygen from the system, 93 parts by mass of Bd was added to the system and the temperature of the mixture was raised to 45°C. Polymerization was started by adding 0.02 parts by mass of PHP, followed by 0.10 parts by mass of SFS, to the reactor. From the start of polymerization until 24 hours, 0.025 parts by mass of PHP, 0.0006 parts by mass of EDTA, and 0.003 parts by mass of FE were added every 3 hours. At 30 hours of polymerization, the polymerization was terminated by defoliation under reduced pressure to remove any monomers remaining that were not used in polymerization. Through this procedure, a polybutadiene rubber latex (R-2) was obtained, with polybutadiene rubber as the main component of the core layer. The volume-average particle size of the polybutadiene rubber particles (core layer) contained in the obtained latex was 200 nm.

[0252] [Manufacturing Example 2: Preparation of Core-Shell Polymer Latex (L-1) (Formation of Shell Layer)] In a glass reactor equipped with a thermometer, stirrer, reflux condenser, nitrogen inlet, and monomer addition device, 271 parts by mass of polybutadiene rubber latex (R-2) (containing 90 parts by mass of polybutadiene rubber particles) and 51 parts by mass of deionized water prepared in Production Example 1 were charged. The charged raw materials were stirred at 60°C while purging with nitrogen. Subsequently, 0.004 parts by mass of EDTA, 0.001 parts by mass of FE, and 0.2 parts by mass of SFS were added to the system. Next, a mixture of shell monomers (9 parts by mass of methyl methacrylate (MMA), 1 part by mass of glycidyl methacrylate (GMA)) and 0.14 parts by mass of cumene hydroperoxide (CHP) was continuously added to the system over 120 minutes. After the addition of the mixture was complete, 0.04 parts by mass of CHP was added to the system. Next, the reaction mixture was stirred for a further 2 hours to complete the polymerization and obtain aqueous latex (L-1) containing core-shell polymer particles (B). The polymerization conversion rate of the monomer components was 99% or higher. The volume-average particle size of the core-shell polymer particles (B) contained in aqueous latex (L-1) was 0.21 μm. The epoxy group content relative to the total mass of the shell layer of the core-shell polymer particles (B) was 0.7 mmol / g.

[0253] [Manufacturing Example 3: Preparation of a dispersion (M-1) in which core-shell polymer particles (B) are dispersed in a curable resin] 132 g of methyl ethyl ketone (MEK) was introduced into a 1 L mixing tank at 25°C. While stirring the MEK, 132 g of core-shell polymer latex (L-1) obtained in Production Example 2 (equivalent to 40 g of core-shell polymer particles) was added to the mixing tank. After the mixture in the mixing tank was uniformly mixed, 200 g of water was added to the mixing tank at a supply rate of 80 g / min. Immediately after the water supply was completed, stirring of the mixture was stopped, and a slurry liquid consisting of floating aggregates and an aqueous phase containing some organic solvent was obtained. Next, the aggregates containing some aqueous phase were left in the mixing tank, and 360 g of the aqueous phase was discharged from the outlet at the bottom of the mixing tank. 90 g of MEK was added to the obtained aggregates and mixed uniformly to obtain a dispersion in which core-shell polymer particles were uniformly dispersed in MEK. 60 g of epoxy resin (JER828, manufactured by Mitsubishi Chemical Corporation, liquid bisphenol A type epoxy resin), which is component (A), was added to the obtained dispersion, and the resulting mixture was mixed. MEK was removed from the resulting mixture using a rotary evaporator. In this way, a dispersion (M-1) was obtained in which core-shell polymer particles (B) were dispersed in epoxy resin (A).

[0254] [Examples 1-7, Comparative Examples 1-7] According to the formulations shown in Tables 1 to 3, each component was weighed and thoroughly mixed to obtain the first and second components of a two-component curable resin composition. After mixing the obtained first and second components, degassing was performed to obtain a curable resin composition. In Tables 1 to 3, the amount of each component is shown in parts by mass. Furthermore, the epoxy resin (A) contained in the first component is explained using the example as an example, as follows: A-1 (45 parts by mass), A-2 (10 parts by mass), and the epoxy resin contained in M-1 (since the mass ratio of core-shell polymer particles to epoxy resin in M-1 is 40:60, 75 parts by mass × 60 / 100 = 45 parts by mass), and the total amount is 100 parts by mass.

[0255] The viscosity of each two-component curable resin composition in Tables 1 to 3 was measured using the following method. Furthermore, the thermal conductivity and elongation (tensile properties) of the cured products obtained from each two-component curable resin composition in Tables 1 to 3 were evaluated using the following method.

[0256] Furthermore, the first component of Comparative Examples 2-4 in Table 1 did not form a paste due to its high viscosity, making it impossible to measure viscosity and thermal conductivity. Similarly, the first and second components of Comparative Example 6 in Table 2 did not form a paste due to their high viscosity, making it impossible to measure viscosity and thermal conductivity.

[0257] <Viscosity> Using a rheometer, the viscosity of each first and second component shown in Tables 1 to 3 at 25°C was measured at a shear rate of 5s. -1 The measurements were taken using [specified method]. The results are shown in Tables 1 to 3.

[0258] <Thermal conductivity> Each of the curable resin compositions shown in Tables 1 to 3 was poured between two Teflon-coated steel plates with a 3 mm thick spacer in between. The resulting steel plates were left at 23°C for one day, and then at 40°C for three days to cure the curable resin composition in the steel plates, obtaining a 3 mm thick cured product. The obtained cured product was cut to obtain two disc-shaped samples with a diameter of 20 mm and a thickness of 3 mm. The thermal conductivity of the cured product was measured using a hot-disk thermal conductivity measuring device TPA-501 (manufactured by Kyoto Electronics Manufacturing Co., Ltd.) by sandwiching a 4φ size sensor between the two disc-shaped samples. The results are shown in Tables 1 to 3.

[0259] <Tensile properties of cured products> Using each curable resin composition shown in Table 3, cured materials with a thickness of 3 mm were obtained using the method described in the section on <Thermal Conductivity> above. The obtained cured materials were punched out into a No. 3 dumbbell shape to obtain samples. Using the obtained samples, tensile tests were performed at 23°C at a tensile speed of 50 mm / min according to JIS K-6251, and the maximum tensile stress (MPa) and elongation at break (%) were measured. The results are shown in Table 3.

[0260] The materials used in Tables 1 to 3 are as follows: <Epoxy resin (A)> A-1: JER828 (manufactured by Mitsubishi Chemical, liquid bisphenol A type epoxy resin at room temperature, epoxy equivalent: 184g / eq~194g / eq) A-2: YED216M (manufactured by Mitsubishi Chemical, alkyl diglycidyl ether, epoxy equivalent: 140g / eq~160g / eq) <Dispersion (M-1) in which polymer fine particles (B) are dispersed in epoxy resin (A)> M-1: Dispersion obtained in the above manufacturing example 3 <Aluminum (C) Oxide> C-1: SA34 (Manufactured by Nippon Light Metal Co., Ltd., average particle size (Dp50): 4.0 μm) C-2: LS-210B (Nippon Light Metal Co., Ltd., average particle size (Dp50): 2.9 μm) <Aluminum oxide other than component (C)> Non-C-1: A11 (Nippon Light Metal Co., Ltd., average particle size (Dp50): 55.0 μm) Non-C-2: A14 (Nippon Light Metal Co., Ltd., average particle size (Dp50): 55.0 μm) Non-C-3: LS-21 (manufactured by Nippon Light Metal Co., Ltd., average particle size (Dp50): 20.0 μm ~ 40.0 μm) <Epoxy hardener (D)> D-1: Hypro ATBN 1300x16 (Huntsman, amine-terminated butadiene-acrylonitrile copolymer, active hydrogen equivalent: 900g / eq) D-2: 1,3-Bis(aminomethyl)cyclohexane (manufactured by Fujifilm Wako Pure Chemical Industries, active hydrogen equivalent: 35.5 g / eq) D-3: Jeffamine D-2000 (Huntsman, poly(oxypropylene)diamine, active hydrogen equivalent: 514g / eq) D-4: Jeffamine D-230 (Huntsman, poly(oxypropylene)diamine, active hydrogen equivalent: 60g / eq) <Aluminum(E) hydroxide> E-1: B303 (Nippon Light Metal Co., Ltd., average particle size (Dp50): 26.0 μm) E-2:BE033 (Nippon Light Metal Co., Ltd., average particle size (Dp50): 3.2μm) <Epoxy curing accelerator (F)> Epoxy curing accelerator: Resorcinol (manufactured by Fujifilm Wako Pure Chemical Industries) <Silane coupling agent (G)> Epoxysilane coupling agent: DOWSIL Z-6040 Silane (manufactured by Toray Dow Corning)

[0261] [Table 1]

[0262] From Table 1, it can be seen that the two-component curable resin compositions of Examples 1 to 2, which contain components (A) to (C) in the first component and components (C) to (D) in the second component, have good thermal conductivity (radiation performance) of the resulting cured product while keeping the viscosities of the first component and the second component relatively low.

[0263] The curable resin compositions of Examples 1, 2 and Comparative Examples 1 to 4 have the same formulation composition except that the added aluminum oxide and component (E) are different. The average particle diameter of the aluminum oxide used in the curable resin compositions of Examples 1 and 2 is small, while the average particle diameter of the aluminum oxide used in the curable resin compositions of Comparative Examples 2 to 4 is large. As a result, in the curable resin compositions of Comparative Examples 2 to 4, the viscosities of the first component and the second component are higher and the workability is worse than those of Examples 1 and 2. In addition, the curable resin composition of Comparative Example 1, which contains no aluminum oxide but only aluminum hydroxide, has lower thermal conductivity than the curable resin compositions of Examples 1 to 2 containing aluminum oxide with a small particle diameter.

[0264] [Table 2]

[0265] From Table 2, it can be seen that the two-component curable resin compositions of Examples 3 to 5, which contain components (A) to (C) in the first component and components (C) to (D) in the second component, have good thermal conductivity of the resulting cured product while keeping the viscosity of the first component or the second component relatively low.

[0266] The curable resin compositions of Examples 3-5 and Comparative Examples 5-6 have the same formulation except for the added aluminum oxide and component (E). While the average particle size of the aluminum oxide used in the curable resin compositions of Examples 3-5 is small, the average particle size of the aluminum oxide used in the curable resin composition of Comparative Example 6 is large, and the first and second components are highly viscous and do not form a paste, resulting in poor workability. Furthermore, the curable resin composition of Comparative Example 5, which contains only aluminum hydroxide and no aluminum oxide, has lower thermal conductivity than the curable resin compositions of Examples 3-5, which contain aluminum oxide with small particle sizes.

[0267] [Table 3]

[0268] Table 3 shows that the two-component curable resin compositions of Examples 6-7, like the two-component curable resin compositions of Examples 1-5, have low viscosity, excellent workability, and good thermal conductivity of the resulting cured product. Furthermore, a comparison between Comparative Example 7, which does not contain component (B), and Examples 6 and 7, which contain component (B), shows that when component (B) is included, the cured product obtained by curing the curable resin composition has a large elongation at break and excellent elongation (flexibility). Therefore, it can be said that Examples 1-5, which contain component (B), also exhibit the same large elongation at break and excellent elongation (flexibility) as Examples 6 and 7.

[0269] In Example 6, the second component uses both an amine compound (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq and an amine compound (D2) with an active hydrogen equivalent of 15 g / eq to 300 g / eq. The cured product obtained by curing the curable resin composition of Example 6 has high elongation (elongation at break) and excellent flexibility, as well as high strength (maximum tensile stress). On the other hand, the second component of Example 7 is an epoxy curing agent (D) using only an amine compound (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq. The cured product obtained by curing the curable resin composition of Example 7 has higher elongation (elongation at break) and better flexibility than Example 6, but the maximum tensile stress is lower than that of Example 6, and the strength of the cured product is slightly lower than that of Example 6.

[0270] In other words, as can be seen from Table 3, when amine compound (D1) and amine compound (D2) are used in combination as epoxy curing agent (D), a cured product with high elongation and higher strength can be obtained. Whether to use amine compound (D1) and amine compound (D2) in combination as epoxy curing agent (D), or to use only one of the amine compounds, should be appropriately selected according to the required elongation and strength of the cured product. [Industrial applicability]

[0271] According to one aspect of the present invention, a novel curable resin composition is available that is superior to conventional two-component or multi-component epoxy resin compositions. One embodiment of the present invention provides a curable resin composition that can provide a cured product with excellent thermal conductivity and elongation, and can be used as a low-viscosity, room-temperature curing two-component or multi-component adhesive. Therefore, the curable resin composition according to one embodiment of the present invention can be preferably used in applications such as adhesives for vehicles and aircraft (structural adhesives), adhesives for secondary batteries such as EV battery cells, structural adhesives for wind power generation, paints, materials for lamination with glass fibers and / or carbon fibers to obtain composite materials, materials for printed circuit boards, solder resists, interlayer insulating films, build-up materials, adhesives for FPCs, electrical insulating materials such as encapsulants for electronic components such as semiconductors and LEDs, die bond materials, underfills, mounting materials for semiconductors (e.g., ACF, ACP, NCF, NCP, etc.), encapsulants for display devices (e.g., liquid crystal panels and OLED displays, etc.) and lighting equipment (e.g., OLED lighting, etc.), and concrete repair composites. A curable resin composition according to one embodiment of the present invention can be suitably used, in particular, as an adhesive for secondary batteries and an adhesive for vehicles.

Claims

1. An adhesive comprising a curable resin composition, The curable resin composition, A two-component or multi-component curable resin composition, It comprises a first component containing epoxy resin (A) and a second component containing epoxy curing agent (D), The curable resin composition further comprises polymer particles (B) having a core-shell structure including a core layer and a shell layer, and aluminum oxide (C), In the total mass of the curable resin composition, the total mass of aluminum oxide (C) is 25% to 90% by mass. The average particle size of the aluminum oxide (C) is 0.3 μm to 10.0 μm. The epoxy curing agent (D) comprises at least one selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers. glue.

2. The adhesive according to claim 1, wherein the curable resin composition further comprises aluminum hydroxide (E).

3. The adhesive according to claim 2, wherein the average particle size of the aluminum hydroxide (E) is 11 μm to 200 μm.

4. The volume-average particle diameter of the polymer particles (B) is 0.15 μm to 0.30 μm, In the polymer particle (B), the ratio of the mass of the core layer to the mass of the shell layer (mass of the core layer / mass of the shell layer) is 65 / 35 to 92 / 8. The shell layer of the polymer particles (B) is a copolymer obtained by polymerizing a monomer component, wherein the monomer component contains 55% by mass or more of an alkyl (meth)acrylate having 1 to 4 carbon atoms in the alkyl group, in a total of 100% by mass of the monomer component. The adhesive according to any one of claims 1 to 3, wherein the monomer component contains 10% to 100% by mass of alkyl (meth)acrylate having one carbon atom in the alkyl group, and 0% to 80% by mass of alkyl (meth)acrylate having four carbon atoms in the alkyl group, in 100% by mass of the monomer component.

5. The epoxy curing agent (D) (i) an amine compound (D1) with an active hydrogen equivalent of 300 g / eq to 1000 g / eq, (ii) An adhesive according to any one of claims 1 to 4, comprising an amine compound (D2) having an active hydrogen equivalent of 15 g / eq or more and less than 300 g / eq.

6. The epoxy curing agent (D) (i) One or more amine compounds selected from the group consisting of amine-terminated polyethers, amine-terminated butadiene nitrile rubbers, modified amine-terminated polyethers, and modified amine-terminated butadiene nitrile rubbers, (ii) An adhesive according to any one of claims 1 to 4, comprising one or more amine compounds selected from the group consisting of aliphatic amines, alicyclic amines, amidoamines, amine-terminated polyethers, modified aliphatic amines, modified alicyclic amines, modified amidoamines, and modified amine-terminated polyethers.

7. The adhesive according to any one of claims 1 to 6, wherein the ratio of the number of moles of epoxy groups in the epoxy resin (A) to the number of moles of active hydrogen groups in the epoxy curing agent (D) (number of moles of epoxy groups in the epoxy resin (A) / number of moles of active hydrogen groups in the epoxy curing agent (D)) is 0.5 or more and 1.5 or less.

8. The polymer particles (B) have a diene rubber in the core layer, The adhesive according to any one of claims 1 to 7, wherein the diene rubber is butadiene rubber and / or butadiene-styrene rubber.

9. The adhesive according to any one of claims 1 to 8, wherein the polymer particles (B) having a core-shell structure have epoxy groups in the shell layer.

10. The polymer particles (B) have epoxy groups in the shell layer, The adhesive according to any one of claims 1 to 9, wherein the content of the epoxy groups in the shell layer relative to the total mass of the shell layer is 0.1 mmol / g to 2.0 mmol / g.

11. The adhesive according to any one of claims 1 to 8, wherein the polymer particles (B) do not contain epoxy groups in the shell layer.

12. The adhesive according to any one of claims 1 to 11, wherein the adhesive is an adhesive for secondary batteries.

13. The adhesive according to any one of claims 1 to 11, wherein the adhesive is an adhesive for vehicles.

14. It comprises two substrates and an adhesive layer formed by curing the adhesive according to any one of claims 1 to 13, The adhesive layer is a laminate formed by joining the two substrates.

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