Curing agent, one-pack resin composition, curable composition, and method for producing curing agent

Abstract

To provide a curing agent, a one-pack resin composition, a curable composition, and a method for producing the curing agent, that achieve high production efficiency and provide excellent adhesion.SOLUTION: A curing agent has a structure comprising a core particle mainly composed of an amine adduct or an amine compound and a shell covering the core particle. The amine adduct is a compound having an amino group produced by a reaction of an amine compound with at least one compound selected from epoxy resin, carboxylic acid compound, sulfonic acid compound, urea compound, and isocyanate compound. The shell is a copolymer comprising at least one monomer selected from aromatic vinyl monomer, (meth)acrylate monomer, vinyl ester monomer, vinyl ether monomer, monoolefin monomer, diolefin monomer, and halogenated olefin monomer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a curing agent, a one-component resin composition, a curable composition, and a method for producing the curing agent. More specifically, the present invention relates to a curing agent that can be produced with high productivity and that can impart good adhesiveness. [Background technology]

[0002] Resin compositions containing epoxy resins are used in a wide range of applications, such as insulating materials, sealing materials, adhesives, and conductive materials for electronic devices and electrical and electronic components. In particular, there has been a demand for electronic devices in recent years to be more highly functional, smaller, and thinner. Furthermore, there has been a demand for miniaturization and higher circuit density in semiconductor chips, which are one type of electronic device. Furthermore, there has also been a demand for significant improvements in productivity.

[0003] When used for the above-mentioned applications, the resin composition is utilized, for example, as a one-component resin composition containing the resin composition and a curing agent. Furthermore, the one-component resin composition may be utilized as a curable composition by further incorporating a diluent, additives, etc. For example, Patent Document 1 discloses a technology using, as the curing agent, a microcapsule-type curing agent having a so-called core-shell structure, in which a core mainly composed of an amine compound is coated with a specific shell. The curing agent is utilized by being incorporated into the one-component resin composition or curable composition. However, such technology leaves room for improvement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2007 / 037378 Summary of the Invention [Problem to be solved by the invention]

[0005] The microcapsule-type curing agent does not exhibit the effect of accelerating the curing reaction until a reaction trigger such as dissolution or destruction of the microcapsules is received. In this sense, the curing agent can be said to have the potential for accelerating the curing reaction.

[0006] Hereinafter, in this specification, "latency" refers to the property that the curing reaction acceleration effect does not appear until a reaction trigger is obtained, and that the curing reaction acceleration effect appears when certain conditions are met. In the following explanation, it is assumed that the microcapsule-type curing agent has a core-shell structure, and the core part of the core-shell structure contains the component that causes the curing reaction to occur.

[0007] The reaction of the microcapsule-type hardener is triggered by the application of pressure, heat, etc. to the hardener, which causes the microcapsules, i.e., the shells, to dissolve or break.

[0008] For example, the core component of a microcapsule-type curing agent is covered with a specific shell. When the curing agent is heated to a temperature above the glass transition temperature of the shell, the shell dissolves or breaks down. At the same time, the core component expands and liquefies. This causes the core component to be exposed or seep out of the shell, thereby accelerating the curing reaction.

[0009] From the above, the advantage of including a microencapsulated curing agent in the one-component resin composition or curable composition described above is that the curing reaction can be selectively induced in a specific temperature range due to the curing agent's latency. Hereinafter, such a latent curing agent will also be referred to as a "latent curing agent." Note that, in this specification, the term "latent curing agent" is intended to include all latent curing agents, and the term "latent curing agent" is used to conceptually include curing agents other than microencapsulated curing agents.

[0010] However, when a cured product is formed using a composition containing a microcapsule-type curing agent, there is a problem in that it is difficult to achieve both excellent physical properties required for circuits with low dielectric properties compatible with recent high-speed communications and maintaining high productivity.

[0011] The present invention has been made in view of the above problems and circumstances, and an object of the present invention is to provide a curing agent, a one-component resin composition, a curable composition, and a method for producing the curing agent, which are highly productive and capable of imparting good adhesion. [Means for solving the problem]

[0012] In order to solve the above problems, the present inventors have investigated the causes of the above problems and have found that the above problems can be solved by using a curing agent having a core-shell structure composed of core particles whose main component is an amine adduct or an amine compound and a shell that covers the core particles, thereby completing the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

[0013] 1. A curing agent having a core-shell structure, the core-shell structure is a structure composed of a core particle containing an amine adduct or an amine compound as a main component and a shell covering the core particle, the amine adduct is a compound having an amino group produced by a reaction between an amine compound and at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and The shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer. A curing agent characterized by:

[0014] 2. A composition containing the curing agent described in item 1 and a resin composition. A one-component resin composition characterized by:

[0015] 3. The resin composition contains an epoxy resin. 3. The one-component resin composition according to claim 2,

[0016] 4. Contains the one-component resin composition described in item 2 A curable composition characterized by:

[0017] 5. Contains inorganic fillers 5. The curable composition according to claim 4,

[0018] 6. It is a semiconductor sealing material 5. The curable composition according to claim 4,

[0019] 7. A method for producing a curing agent having a core-shell structure, comprising: the core-shell structure is a structure composed of a core particle containing an amine adduct or an amine compound as a main component and a shell covering the core particle, forming the core particles; and forming the shell by associating and fusing a resin onto the surface of the core particle, the amine adduct is a compound having an amino group produced by a reaction between an amine compound and at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and The shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer. A method for producing a curing agent comprising the steps of: [Effects of the Invention]

[0020] According to the above-mentioned means of the present invention, it is possible to provide a curable composition that can be produced with high productivity and that can impart good adhesiveness, and a method for producing the same. The mechanism by which the effects of the present invention are manifested or the mechanism of action is not clear, but is speculated as follows.

[0021] The curing agent of the present invention has a core-shell structure, and the core-shell structure is composed of a core particle mainly composed of an amine adduct or an amine compound, and a shell covering the core particle. The amine adduct is a compound having an amino group produced by reacting an amine compound with at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and the shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer.

[0022] As mentioned above, conventional microencapsulated curing agents are core-shell latent curing agents, and the curing reaction acceleration effect of these microencapsulated curing agents does not appear until a reaction trigger is obtained.

[0023] For example, the microcapsule-type curing agent of Patent Document 1 has an amine compound, which has the effect of accelerating the curing reaction, as the main component of the core, and the core component is covered by a microcapsule shell. Since the core component and the shell component are bound by a covalent bond, it is thought that a large amount of unreacted part of the shell will remain.

[0024] The presence of unreacted portions of the shell deteriorates the electrical properties of the cured product obtained by curing a one-component resin composition or a curable composition containing a microcapsule-type curing agent.

[0025] Furthermore, when heat is applied to the one-component resin composition or the curable composition, the shell of the microcapsule-type curing agent melts or is destroyed, and then mixes with the core component or other components.

[0026] If the unreacted portion of the shell mixes with the core component or other components, the unreacted portion of the shell will not be incorporated into the one-component resin composition or the curable composition but will become a foreign substance, causing the compositions to become non-uniform, which in turn causes the electrical properties of the cured product obtained by curing the one-component resin composition or the curable composition to become non-uniform.

[0027] The curing agent of the present invention is a latent curing agent having a core-shell structure composed of core particles containing components that accelerate the curing reaction and a shell that covers the core particles. The core particles are associated and fused with the shell.

[0028] In this specification, the term "association and fusion" refers to binding by relatively weak intermolecular forces due to the parallel progression of aggregation and fusion.

[0029] Because intermolecular forces are not as strong as covalent bonds, the curing agent of the present invention melts, breaks, or peels off the shell with a weaker reaction trigger than a microcapsule-type curing agent. This results in a curing reaction acceleration effect. An example of this weak reaction trigger is heating. In other words, a curing reaction acceleration effect with high temperature responsiveness is obtained. Furthermore, one-component resin compositions and the like can be thickened to the desired viscosity or hardness and the time until curing can be shortened, thereby improving productivity.

[0030] As described above, since the curing agent of the present invention is a latent curing agent, the viscosity increasing rate of the composition can be suppressed until a reaction trigger is obtained, and therefore, when the curing agent is used as an adhesive for joining different materials, for example, a sufficient joining time can be ensured.

[0031] Furthermore, when a composition containing the curing agent of the present invention is used and heated, its latency is expressed at a lower temperature, thereby accelerating the curing reaction. Therefore, when the composition is used in a fixing member, for example, the thermal stress on the fixing member can be reduced, ensuring resistance to temperature fluctuations in the usage environment. Furthermore, the time required for curing can be shortened.

[0032] Furthermore, the unreacted portion of the shell is small, and the amount of the shell incorporated into the core component and other compositions is uniform, thereby ensuring uniform excellent electrical properties. As a result, even when a composition containing the curing agent of the present invention is used as an adhesive for joining members made of different materials, deformation of the members after curing of the adhesive due to differences in the thermal expansion coefficients between the members does not occur, and it is presumed that the composition has high heat cycle resistance and does not peel at the joint. [Brief explanation of the drawings]

[0033] [Figure 1] An example of a conceptual diagram of the curing agent of the present invention [Figure 2] An example of a conceptual diagram of the one-component resin composition of the present invention [Figure 3] An example of a conceptual diagram of the curable composition of the present invention [Figure 4] An example of a simplified diagram showing how a molded product is made using compression molding DETAILED DESCRIPTION OF THE INVENTION

[0034] The curing agent of the present invention has a core-shell structure, and the core-shell structure is composed of a core particle mainly composed of an amine adduct or an amine compound, and a shell covering the core particle. The amine adduct is a compound having an amino group produced by reacting an amine compound with at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and the shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer. This feature is a technical feature common to or corresponding to each of the following embodiments (modes).

[0035] The one-component resin composition of the present invention contains the curing agent of the present invention and a resin composition.

[0036] The resin composition preferably contains an epoxy resin from the viewpoints of improving adhesion by accelerating the curing reaction and durability against organic solvents, and also from the viewpoint of obtaining a cured product with a low coefficient of thermal expansion (CTE).

[0037] The curable composition of the present invention contains the one-component resin composition of the present invention.

[0038] The curable composition preferably contains an inorganic filler from the viewpoints of reducing the thermal expansion coefficient and improving the toughness of the cured product.

[0039] The curable composition is suitable for use as a semiconductor sealing material.

[0040] The method for producing a curing agent of the present invention is a method for producing a curing agent having a core-shell structure, wherein the core-shell structure is composed of core particles containing an amine adduct or an amine compound as a main component, and a shell covering the core particles, and the method comprises the steps of forming the core particles and associating and fusing a resin to the surface of the core particles to form the shell, wherein the amine adduct is a compound having an amino group produced by reacting an amine compound with at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and the shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer.

[0041] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after it are included as lower and upper limits.

[0042] However, advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for illustrative purposes only and are not intended to define the limits of the invention.

[0043] [ Hardener ] 1. Overview The curing agent of the present invention has a core-shell structure, and the core-shell structure is composed of a core particle mainly composed of an amine adduct or an amine compound, and a shell covering the core particle. The amine adduct is a compound having an amino group produced by reacting an amine compound with at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and the shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer.

[0044] As described above, the core component and the shell component of the microcapsule-type curing agent are bound by a covalent bond, and therefore, the unreacted portion of the shell increases.

[0045] The presence of unreacted shells reduces the electrical properties of the cured product obtained by curing a one-component resin composition or curable composition containing a microcapsule-type curing agent, and also leads to non-uniformity in the amount of shell incorporated into the one-component resin composition or curable composition, resulting in non-uniformity in the electrical properties of the cured product.

[0046] The core particles and shells in the curing agent of the present invention are not bound by a strong covalent bond as in conventional microcapsule-type curing agents, but are associated and fused together. As mentioned above, in this specification, "association and fusion" refers to a bond formed by a relatively weak intermolecular force due to the parallel progression of aggregation and fusion.

[0047] Because intermolecular forces are weaker than covalent bonds, the shell of the curing agent having a core-shell structure of the present invention melts, breaks, or peels off with a weaker reaction trigger than the shell of a microcapsule-type curing agent. This results in a curing reaction acceleration effect. An example of this weak reaction trigger is heating. In other words, a highly temperature-responsive curing reaction acceleration effect is achieved. Furthermore, one-component resin compositions and the like can be thickened to the desired viscosity or hardness and the time required for curing can be shortened, thereby improving productivity.

[0048] Furthermore, since the curing agent of the present invention has no unreacted shell when heated, it does not deteriorate the electrical properties of the cured product of a one-component resin composition or the like, and can form a cured product with uniform electrical properties, resulting in excellent adhesiveness.

[0049] 2. Core particles FIG. 1 is a conceptual diagram of an example of a curing agent of the present invention. Curing agent H has a core-shell structure. The core particle C and shell S of curing agent H are associated and fused together, and the core C is coated by the shell S in a wet and spread manner. The main component of the core particle C is an amine adduct or an amine compound.

[0050] (2.1) Amine adducts The term "amine adduct" refers to a compound having an amine structure that is produced by reacting at least one compound selected from the group consisting of epoxy resins, carboxylic acid compounds, sulfonic acid compounds, urea compounds, and isocyanate compounds with an amine compound.

[0051] An "adduct" is a compound produced by the direct addition of two or more different molecules, resulting in a single reaction product.

[0052] The term "amine compound" refers to a compound having one or more primary, secondary, or tertiary amino groups. Examples of the amine compound include aliphatic amines, alicyclic amines, aromatic amines, hydrazides, guanidine derivatives, and imidazoles.

[0053] The amine compound is preferably imidazole, and among amine adducts, the amine adduct produced by the reaction of an epoxy resin with imidazole is particularly preferred, which enhances the curing property of the curing agent H and ensures storage stability.

[0054] (2.1.1) Compounds that react with amine compounds (epoxy resin) Epoxy resins are resinous compounds with reactive epoxy groups at the ends of their molecules, and are thermosetting compounds formed by polymerization of these compounds with curing agents. Cured epoxy resins have excellent mechanical, electrical, and thermal properties, chemical resistance, and adhesive properties.

[0055] Examples of the epoxy resin include polyepoxy compounds and monoepoxy compounds. Also, mixtures thereof can be used. From the viewpoint of improving the storage stability of the curable composition, the epoxy resin is preferably a polyepoxy compound.

[0056] Examples of polyvalent epoxy compounds include the following compounds (1) to (11), and these epoxy resins may be used alone or in combination. do. (1) Bisphenol-type epoxy resins made by glycidylating bisphenols (2) Epoxy resins glycidylated with other dihydric phenols (3) Epoxy resins glycidylated with trisphenols (4) Epoxy resins glycidylated with tetrakisphenols (5) Novolac-type epoxy resins obtained by glycidylating novolacs (6) Aliphatic ether epoxy resins obtained by glycidylating polyhydric alcohols (7) Ether ester type epoxy resins with glycidyl hydroxycarboxylic acids (8) Ester-type epoxy resins obtained by glycidylating polycarboxylic acids (9) Glycidylated amine compounds (10) Glycidyl epoxy resins such as amine epoxy resins (11) Alicyclic epoxides

[0057] The polyepoxy compound is preferably a glycidyl-type epoxy resin, which dramatically increases the productivity of the amine adduct. From the viewpoint of improving adhesiveness and heat resistance, the polyepoxy compound is preferably a glycidyl-type epoxy resin obtained by glycidylating a polyhydric phenol.

[0058] The polyfunctional epoxy compound is more preferably a bisphenol-type epoxy resin, even more preferably an epoxy resin obtained by glycidylating bisphenol F, and even more preferably an epoxy resin obtained by glycidylating bisphenol A.

[0059] (1) Bisphenol-type epoxy resins made by glycidylating bisphenols Examples of bisphenol-type epoxy resins obtained by glycidylating bisphenols include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, tetrachlorobisphenol A, and tetrafluorobisphenol A.

[0060] (2) Epoxy resins glycidylated with other dihydric phenols Other examples of epoxy resins obtained by glycidylating dihydric phenols include biphenol, dihydroxynaphthalene, and 9,9-bis(4-hydroxyphenyl)fluorene.

[0061] (3) Epoxy resins glycidylated with trisphenols Examples of epoxy resins obtained by glycidylating trisphenols include 1,1,1-tris(4-hydroxyphenyl)methane and 4,4-(1-(4-(1-(4-hydroxyphenyl)-1-methylethyl)phenyl)ethylidene)bisphenol.

[0062] (4) Epoxy resins glycidylated with tetrakisphenols Examples of epoxy resins obtained by glycidylating tetrakisphenols include 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane.

[0063] (5) Novolac-type epoxy resins obtained by glycidylating novolacs Examples of novolac-type epoxy resins obtained by glycidylating novolacs include phenol novolac, cresol novolac, bisphenol A novolac, brominated phenol novolac, and brominated bisphenol A novolac.

[0064] (6) Aliphatic ether epoxy resins obtained by glycidylating polyhydric alcohols Examples of aliphatic ether type epoxy resins obtained by glycidylating polyhydric alcohols include epoxy resins obtained by glycidylating polyhydric phenols, glycerin, and polyethylene glycol.

[0065] (7) Ether ester type epoxy resin obtained by glycidylating hydroxycarboxylic acid Examples of ether ester type epoxy resins obtained by glycidylating hydroxycarboxylic acids include p-oxybenzoic acid and β-oxynaphthoic acid.

[0066] (8) Ester-type epoxy resin obtained by glycidylating polycarboxylic acid Examples of ester-type epoxy resins obtained by glycidylating polycarboxylic acids include phthalic acid and terephthalic acid.

[0067] (9) Glycidylated amine compounds Examples of glycidyl amine compounds include 4,4-diaminodiphenylmethane and m-aminophenol.

[0068] (10) Glycidyl-type epoxy resins such as amine-type epoxy resins Examples of glycidyl type epoxy resins such as amine type epoxy resins include triglycidyl isocyanurate.

[0069] (11) Alicyclic epoxides Examples of alicyclic epoxides include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate.

[0070] Examples of monoepoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexoate, and glycidyl benzoate.

[0071] (carboxylic acid compounds) Examples of the carboxylic acid compound include succinic acid, adipic acid, sebacic acid, phthalic acid, and dimer acid.

[0072] (sulfonic acid compounds) Examples of sulfonic acid compounds include ethanesulfonic acid and p-toluenesulfonic acid.

[0073] (urea compound) Examples of the urea compound include urea, methyl urea, dimethyl urea, ethyl urea, and t-butyl urea.

[0074] (Isocyanate compounds) Examples of the isocyanate compound include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aliphatic triisocyanates, and polyisocyanates.

[0075] Examples of the aliphatic diisocyanate include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0076] Examples of alicyclic diisocyanates include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis(isocyanatomethyl)-cyclohexane, and 1,3-bis(2-isocyanatopropyl-2-yl)-cyclohexane.

[0077] Examples of aromatic diisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, and 1,5-naphthalene diisocyanate.

[0078] Examples of the aliphatic triisocyanate include 1,6,11-undecane triisocyanate, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatomethylhexane, 2,6-diisocyanatohexanoic acid-2-isocyanatoethyl, and 2,6-diisocyanatohexanoic acid-1-methyl-2-isocyanatoethyl.

[0079] Examples of the polyisocyanate include polymethylene polyphenyl polyisocyanate and polyisocyanates derived from the above diisocyanate compounds.

[0080] Examples of polyisocyanates derived from the above diisocyanates include isocyanurate-type polyisocyanates, biuret-type polyisocyanates, urethane-type polyisocyanates, allophanate-type polyisocyanates, and carbodiimide-type polyisocyanates.

[0081] (2.1.2) Amine compound for forming adduct The amine compound may be a compound having a tertiary amino group or a compound not having a tertiary amino group, specifically, the following (1) and (2): (1) A compound having at least one primary amino group and / or secondary amino group but no tertiary amino group (2) A compound having at least one tertiary amino group and at least one active hydrogen group.

[0082] (Compounds without a tertiary amino group) Examples of compounds having no tertiary amino group include the following (1-1) and (1-2). (1-1) Primary amines without a tertiary amino group (1-2) Secondary amines without a tertiary amino group

[0083] Examples of primary amines having no tertiary amino group include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0084] Examples of secondary amines having no tertiary amino group include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperidine, piperidone, diphenylamine, phenylmethylamine, and phenylethylamine.

[0085] (Compounds with a tertiary amino group) Examples of the active hydrogen group in the compound having a tertiary amino group include a primary amino group, a secondary amino group, a hydroxyl group, a thiol group, a carboxylic acid, and a hydrazide group.

[0086] Examples of compounds having an active hydrogen group include imidazole, imidazoline, amino alcohols, aminophenols, tertiary aminoamines, aminomercaptans, aminocarboxylic acids, and aminohydrazides.

[0087] The amine compound is preferably imidazole, and among amine adducts, the amine adduct produced by the reaction of an epoxy resin with imidazole is particularly preferred, which enhances the curing property of the curing agent H and ensures storage stability.

[0088] Examples of imidazoles include imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, 2-butylimidazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, 1-allylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 4-formylimidazole, and 2-butyl-4-formylimidazole. 2-Butyl-4-hydroxymethylimidazole, 2-butyl-4-chloro-5-formylimidazole, 2-hydroxymethylimidazole, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, 2-hydroxymethyl-1-benzylimidazole, 4-hydroxymethyl-2-methylimidazole, 4-formyl-1-methylimidazole, 5-formyl-1-methylimidazole, 4-formyl-5-methylimidazole, 4-formyl-1-tritylimidazole, 4- Carboxymethylimidazole, 4-carboxyethylimidazole, 4-carboxylic acid imidazole, 2-aminoimidazole sulfate, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-formylimidazole, 1-benzyl-5-hydroxymethylimidazole, 1-benzyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethylimidazole, 4-methylimidazole, 1-cyanoethyl Examples thereof include aminoethyl-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-aminoethyl-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, and 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole.

[0089] Examples of amino alcohols include 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1-butoxymethyl-2-dimethylaminoethanol, methyldiethanolamine, triethanolamine, and N-β-hydroxyethylmorpholine.

[0090] Examples of aminophenols include 2-(dimethylaminomethyl)phenol and 2,4,6-tris(dimethylaminomethyl)phenol.

[0091] Examples of tertiary aminoamines include dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dipropylaminoethylamine, dibutylaminoethylamine, N-methylpiperazine, N-aminoethylpiperazine, and diethylaminoethylpiperazine.

[0092] Examples of aminomercaptans include 2-dimethylaminoethanethiol, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptopyridine, and 4-mercaptopyridine.

[0093] Examples of aminocarboxylic acids include N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, and picolinic acid.

[0094] Examples of aminohydrazides include N,N-dimethylglycine hydrazide, nicotinic acid hydrazide, isonicotinic acid hydrazide, and the like.

[0095] As the amine compound, a compound having at least one tertiary amino group and at least one active hydrogen group is preferred because it has an excellent balance between storage stability and curability. As the compound having an active hydrogen group, imidazoles are more preferred, and 2-methylimidazole or 2-ethyl-4-methylimidazole is even more preferred.

[0096] (2.2) Amine compound as the main component When the main component of the core particle C according to the present invention is not an amine adduct, the main component is an amine compound.

[0097] The amine compound as the main component may be the same as the amine compound described above. When the main component is an amine compound, a particularly preferred compound as the amine compound is imidazole.

[0098] (imidazole) The curing agent of the present invention may contain imidazole as the main component. Imidazole is a low molecular weight amine compound, a type of amine heterocyclic aromatic compound containing nitrogen atoms at the 1st and 3rd positions on a five-membered ring.

[0099] Examples of imidazoles are the same as those listed above for the amine compounds having a tertiary amino group. Among these, 2-methylimidazole, 2-phenylimidazole, and 1,2-dimethylimidazole are preferred from the viewpoint of improving the storage stability and reactivity of the main component of the core particles. 2-methylimidazole and 1,2-dimethylimidazole are more preferred from the viewpoint of reducing steric hindrance to the active site.

[0100] (2.3) Core particle diameter The particle size of the core particles according to the present invention is preferably within the range of 0.1 to 12 μm. If the particle size of the curing agent is greater than 12 μm, the composition of the cured product obtained by curing the one-component resin composition or curable composition described below will not be uniform. Furthermore, when these compositions are blended, large aggregates are likely to be formed, which will deteriorate the physical properties of the cured product. If the particle size of the core particles is smaller than 0.1 μm, aggregation will occur between the components of the core particles, making it difficult to form a thin shell.

[0101] Examples of methods for controlling the particle size of core particles include a method in which aggregated core particle components are coarsely pulverized and finely pulverized, and then precisely classified to obtain a desired average particle size, and a method in which dissolved core particle components are spray-dried under controlled conditions to obtain a desired average particle size.

[0102] Although devices such as ball mills, attritors, bead mills, and jet mills can be used as needed to crush core particles, impact crushers are often used. Examples of impact crushers used here include jet mills such as swirling flow powder collision jet mills and powder collision counter jet mills. Jet mills are devices that use high-speed jet streams of air or other medium to cause solid materials to collide with each other and break down the particles into fine particles.

[0103] As the device for carrying out the classification operation, a general classifier using wind power, or various other dry classifiers such as air separators, micron separators, microbrex, and accucut can be used.

[0104] 3. Shell The shell that coats the core particle according to the present invention is a copolymer composed of at least one of the following monomers:

[0105] (1) Aromatic vinyl monomers (2) (Meth)acrylic acid ester monomers (3) Vinyl ester monomers (4) Vinyl ether monomers (5) Monoolefin monomers (6) Diolefin monomers (7) Halogenated olefin monomers

[0106] The above-mentioned monomers are radically polymerizable monomers, and when the radically polymerizable monomers are polymerized together, a radically polymerizable crosslinking agent can be used as needed.

[0107] As the monomer constituting the shell, a monomer other than the above-mentioned monomers may be used, and conventionally known monomers may be used alone or in combination of two or more depending on the required properties.

[0108] As the monomer other than the above-mentioned monomers, it is preferable to use, for example, at least one monomer selected from radical polymerizable monomers having an acidic group and radical polymerizable monomers having a basic group.

[0109] (3.1) Monomer (aromatic vinyl monomer) Examples of aromatic vinyl monomers include styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof.

[0110] ((Meth)acrylic acid ester monomer) Examples of the (meth)acrylic acid ester monomer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

[0111] (Vinyl ester monomer) Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate.

[0112] (Vinyl ether monomer) Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, and vinyl phenyl ether.

[0113] (monoolefin monomer) Examples of monoolefin monomers include ethylene, propylene, isobutylene, 1-butene, 1-pentene, and 4-methyl-1-pentene.

[0114] (Diolefin monomer) Examples of diolefin monomers include butadiene, isoprene, and chloroprene.

[0115] (Halogenated olefin monomer) Examples of halogenated olefin monomers include vinyl chloride, vinylidene chloride, and vinyl bromide.

[0116] (Radical polymerizable monomer having an acidic group) Examples of the radically polymerizable monomer having an acidic group include carboxylic acid group-containing monomers such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, and maleic acid monooctyl ester, as well as sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfosuccinic acid, and allylsulfosuccinic acid octyl.

[0117] All or part of the radical polymerizable monomer having an acidic group may have a structure of an alkali metal salt such as sodium or potassium, or all or part of the radical polymerizable monomer having an acidic group may have a structure of an alkaline earth metal salt such as calcium.

[0118] The amount of the radical polymerizable monomer having an acidic group in the monomer mixture used to form the shell is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.1 to 15% by mass.

[0119] (Radical polymerizable monomer having a basic group) Examples of the radical polymerizable monomer having a basic group include amine compounds such as primary amines, secondary amines, tertiary amines, and quaternary ammonium salts.

[0120] Examples of amine compounds include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and quaternary ammonium salts thereof. Also included are 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt, acrylamide, N-butylacrylamide, N,N-dibutylacrylamide, piperidyl acrylamide, methacrylamide, N-butylmethacrylamide, N-octadecylacrylamide, vinylpyridine, vinylpyrrolidone, vinyl N-methylpyridinium chloride, vinyl N-ethylpyridinium chloride, N,N-diallylmethylammonium chloride, and N,N-diallylethylammonium chloride.

[0121] The content of the radical polymerizable monomer having a basic group in the monomer mixture used to form the shell is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.1 to 15% by mass.

[0122] (3.2) Other ingredients When forming the shell, other components such as a radical polymerizable crosslinking agent, a chain transfer agent, a radical polymerization initiator, and a surfactant may be used as needed.

[0123] (Radical polymerizable crosslinking agent) Examples of the radically polymerizable crosslinking agent include compounds having two or more unsaturated bonds, such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

[0124] The content of the radical polymerizable crosslinking agent in the monomer mixture used to form the shell is preferably within the range of 0.1 to 10% by mass.

[0125] (chain transfer agent) A commonly used chain transfer agent may be used to adjust the molecular weight of the resin, and is not particularly limited, but examples thereof include mercaptans such as octyl mercaptan, dodecyl mercaptan, and tert-dodecyl mercaptan, and styrene dimer.

[0126] (Radical polymerization initiator) Any water-soluble radical polymerization initiator can be used as the radical polymerization initiator for obtaining the resin.

[0127] Examples of radical polymerization initiators include persulfates, azo compounds, and peroxide compounds. Examples of persulfates include potassium persulfate and ammonium persulfate. Examples of azo compounds include 4,4'-azobis-4-cyanovaleric acid, salts of 4,4'-azobis-4-cyanovaleric acid, and salts of 2,2'-azobis(2-amidinopropane).

[0128] The radical polymerization initiator can be combined with a reducing agent as needed to form a redox initiator, which increases the polymerization activity, lowers the polymerization temperature, and is expected to shorten the polymerization time.

[0129] The polymerization temperature is not particularly limited as long as it is equal to or higher than the minimum radical generation temperature of the radical polymerization initiator. The polymerization temperature is, for example, within a range of 50 to 90°C. However, by using a polymerization initiator that initiates polymerization at room temperature, such as a combination of hydrogen peroxide and a reducing agent such as ascorbic acid, as the radical polymerization initiator, it is also possible to carry out polymerization at a temperature higher than room temperature.

[0130] (surfactant) A surfactant is used when polymerizing a radical polymerizable monomer. The surfactant is not particularly limited, but for example, an ionic surfactant such as a sulfonate, a sulfate ester salt, or a fatty acid salt is suitable for polymerizing a radical polymerizable monomer.

[0131] Examples of sulfonates include sodium dodecylbenzenesulfonate and sodium arylalkyl polyethersulfonate. Examples of sulfate ester salts include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, and sodium octyl sulfate. Examples of fatty acid salts include sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, potassium stearate, and calcium oleate.

[0132] In addition, nonionic surfactants such as polyethylene oxide, polypropylene oxide, a combination of polypropylene oxide and polyethylene oxide, an ester of polyethylene glycol and a higher fatty acid, alkylphenol polyethylene oxide, an ester of a higher fatty acid and polyethylene glycol, an ester of a higher fatty acid and polypropylene oxide, and a sorbitan ester may also be used.

[0133] The surfactant is used as an emulsifier in the emulsion polymerization step, but may also be used in other steps or for purposes other than as an emulsifier.

[0134] (3.3) How to confirm the bonding state between the core particle and the shell The bonding state between the core particle and the shell can be confirmed by FT-IR measurement to determine whether they are bonded by intermolecular forces or chemical bonds. FT-IR measurement involves, for example, using an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) to measure the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle. Then, whether the bonding state between the core particle and the shell is bonded by intermolecular forces or chemical bonds can be confirmed by whether an absorption spectrum is present in an absorption wavelength range within the desired range.

[0135] (3.4) Particle size of hardener The particle size of the curing agent of the present invention is preferably 0.5 to 7.0 μm, although the particle size of the core particle described above is preferably within the range of 0.1 to 12 μm and can be varied as appropriate depending on the thickness of the shell covering the core particle. When the particle size of the core particle is 0.5 μm or more, the curing agent of the present invention can be stably dispersed when incorporated into a resin composition or the like. When the particle size of the core particle is 7.0 μm or less, the curing agent of the present invention can be incorporated into a resin composition or the like and cured uniformly.

[0136] 4. Manufacturing method of hardener The method for producing a curing agent of the present invention is a method for producing a curing agent having a core-shell structure, wherein the core-shell structure is composed of core particles containing an amine adduct or an amine compound as a main component, and a shell covering the core particles, and the method comprises the steps of forming the core particles and associating and fusing a resin to the surface of the core particles to form the shell, wherein the amine adduct is a compound having an amino group produced by reacting an amine compound with at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and the shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer.

[0137] (4.1) Step of forming core particles In the step of forming core particles, when the main component is an amine adduct, an amine adduct is prepared and used as the core particles, whereas when the main component is an amine compound, the amine compound is used as it is as the core particles.

[0138] (Preparation of amine adducts) To prepare the amine adduct, first, at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound is mixed with an amine compound and an organic solvent to cause a reaction, and then the organic solvent is distilled off under reduced pressure to prepare a solid amine adduct, which is used as the core particle.

[0139] (4.2) Shell Formation Process In the shell formation process, a curing agent is produced by forming a core-shell structure by associating and fusing a resin onto the surface of the prepared core particles. In other words, in the shell formation process, the core particles are coated with a shell using the association and fusion method.

[0140] Here, the "association fusion method" refers to a method in which aggregation and fusion are carried out in parallel, and when the aggregated particles grow to the desired size, an aggregation terminator is added to stop the particle growth. Note that the above-mentioned "aggregation" refers to the gathering of particles by interactions such as electrostatic interactions, hydrogen bonds, and van der Waals forces.

[0141] In this step, first, a polymerization step is carried out to prepare the shell resin particles, which can basically be carried out by a conventionally known polymerization method such as emulsion polymerization or suspension polymerization.

[0142] A preferred polymerization method involves dispersing a monomer solution, prepared by dissolving a specific monomer in an aqueous medium containing a surfactant at a concentration below the critical micelle concentration, into oil droplets using mechanical energy to prepare a dispersion. A water-soluble polymerization initiator is added to the resulting dispersion to cause radical polymerization. Hereinafter, this method will be referred to as the "mini-emulsion method."

[0143] Instead of adding the water-soluble polymerization initiator, or in addition to adding the water-soluble polymerization initiator, an oil-soluble polymerization initiator may be added to the monomer solution.

[0144] The dispersing machine for dispersing oil droplets using mechanical energy is not particularly limited, and examples include a stirring device equipped with a high-speed rotating rotor, the CLEARMIX (manufactured by M Technique Co., Ltd.), an ultrasonic dispersing machine, a mechanical homogenizer, a Manton-Gaulin homogenizer, and a pressure homogenizer. The dispersed particle diameter is 10 to 1000 nm, preferably 30 to 300 nm.

[0145] The molecular weight of the shell resin particles can be adjusted by the amount of polymerization initiator, the reaction temperature, the addition of a chain transfer agent, etc. When a chain transfer agent is used to adjust the molecular weight of the shell resin particles, it is preferable to add the chain transfer agent in a mixture with the radical polymerizable monomer.

[0146] The particle diameter of the shell resin particles is preferably within a range of 50 to 500 nm in terms of weight average particle diameter.

[0147] (Preparation of Shell Resin Particle Dispersion) The shell resin particle dispersion can be prepared by a conventionally known polymerization method such as emulsion polymerization or suspension polymerization. For example, a suitable method is to prepare a shell resin particle dispersion according to a conventional method such as emulsion polymerization, add a radical polymerizable monomer to the shell resin particle dispersion, and polymerize the resulting mixture to form a multilayer (composite) structure.

[0148] As an example of the above method, the following method can be mentioned, in which the polymerization step is divided into three stages, the shell resin particles are made into composite resin particles, and the resin particles are multilayered (composite) with a high molecular weight resin, an intermediate molecular weight resin, and a low molecular weight resin.

[0149] [Preparation of a dispersion containing core particles for shell resin particles: First-stage polymerization] A dispersion liquid of a high molecular weight resin is prepared by a polymerization treatment (first-stage polymerization) according to a conventional method. Hereinafter, the "core particles of the shell resin particles" will be simply referred to as "core resin particles for the shell," and the "dispersion liquid of a high molecular weight resin" will be referred to as "latex [H]."

[0150] [Formation of intermediate layer on core resin particles for shell: second-stage polymerization] A polymerization initiator and a polymerizable monomer mixture for obtaining a medium molecular weight resin are added to the latex [H] to prepare a mixed dispersion with the latex [H].

[0151] The mixed dispersion with latex [H] is polymerized (second-stage polymerization) to prepare a dispersion of resin particles in which the surfaces of resin particles made of high molecular weight resin are coated with a medium molecular weight resin. Hereinafter, this "dispersion of resin particles in which the surfaces of resin particles made of high molecular weight resin are coated with a medium molecular weight resin" will also be referred to as latex [HM].

[0152] [Formation of outer layer covering intermediate layer: third-stage polymerization] A polymerization initiator and a polymerizable monomer mixture for obtaining a low molecular weight resin are added to the above latex [HM] to prepare a mixed dispersion with the latex [HM].

[0153] The mixed dispersion with latex (HM) is polymerized (third-stage polymerization) to prepare a dispersion containing composite resin particles consisting of a core made of a high molecular weight resin, an intermediate layer made of a medium molecular weight resin, and an outer layer made of a low molecular weight resin. Hereinafter, this "dispersion containing composite resin particles consisting of a core made of a high molecular weight resin, an intermediate layer made of a medium molecular weight resin, and an outer layer made of a low molecular weight resin" will also be referred to as "latex (HML)."

[0154] [Specific example of the case where the shell resin particles are not composite resin particles] When the shell resin particles are not composite resin particles, the shell resin particle dispersion liquid can be prepared, for example, as follows. (1) A surfactant-containing aqueous medium prepared by dissolving a surfactant in ion-exchanged water is mixed with a polymerization initiator-containing solution prepared by dissolving a radical polymerization initiator in ion-exchanged water, and the mixture is heated to prepare a mixed solution [1] containing a surfactant and a radical polymerization initiator.

[0155] The term "aqueous medium" refers to a medium consisting of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. When an aqueous medium is used as an emulsifier, an aqueous solution of a surfactant is used as the aqueous medium.

[0156] As the water-soluble organic solvent, in addition to the surfactant used as an emulsifier, for example, methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, tetrahydrofuran, etc. As the organic solvent, an alcohol-based organic solvent that does not dissolve the obtained resin can also be used.

[0157] (2) A monomer mixture [1] containing a radical polymerizable monomer is prepared. At this time, the monomer mixture [1] preferably contains at least one of a radical polymerizable monomer having an acidic group and a radical polymerizable monomer having a basic group in a proportion within a range of 0.1 to 20 mass %.

[0158] After heating, when the mixed solution [1] containing the surfactant and the radical polymerization initiator reaches a predetermined temperature, a monomer mixture [1] containing a radical polymerizable monomer is added, and the system is heated while being stirred, usually under a nitrogen atmosphere, to prepare a dispersion solution [1] of shell resin particles.

[0159] The above-mentioned “predetermined temperature” refers to the “polymerization temperature.” The polymerization temperature and polymerization time can be appropriately set within a range in which the polymerization reaction occurs.

[0160] (Shell fusion to core particle) The core particles are subjected to the association and fusion treatment in a state where they are dispersed in an aqueous medium. The aqueous medium in which the core particles are dispersed can be, for example, an aqueous solution in which a surfactant is dissolved at a concentration equal to or higher than the critical micelle concentration (CMC). The surfactant can be the same as the surfactant used as an emulsifier in preparing the shell resin particle dispersion.

[0161] The dispersing machine used for the dispersion treatment of the core particles is not particularly limited, but preferred examples include a stirring device equipped with a rotor that rotates at high speed, such as "CLEARMIX" (manufactured by M Technique Co., Ltd.), an ultrasonic dispersing machine, a mechanical homogenizer, a pressure dispersing machine such as a Manton-Gaulin homogenizer or a pressure homogenizer, and a media-type dispersing machine such as a Getzmann mill or a diamond fine mill.

[0162] To fuse the core particles and shells, it is necessary to add a flocculant at a critical flocculation concentration or higher to a dispersion in which the core particles and shell resin particles are dispersed, and to heat the dispersion at a temperature relatively close to the glass transition temperature (Tg) of the shell resin particles. As long as the heating temperature is relatively close to the glass transition temperature (Tg), the fusing can occur even at a temperature lower than the glass transition temperature (Tg). Furthermore, if the heating temperature is too high, the shell will melt, which is undesirable.

[0163] The temperature range suitable for association and fusion, based on the glass transition temperature (Tg) of the shell resin particles, is (Tg-10) to (Tg+50°C), and particularly preferably (Tg-5) to (Tg+30°C).

[0164] The "flocculant" used in the association and fusion may include alkali metal salts and alkaline earth metal salts.

[0165] Examples of alkali metals include lithium, potassium, and sodium. Examples of alkaline earth metals include magnesium, calcium, strontium, and barium. Among these, potassium, sodium, magnesium, calcium, and barium are preferred as flocculants. Examples of counter ions (anions constituting salts) of the alkali metals or alkaline earth metals include chloride ions, bromide ions, iodide ions, carbonate ions, and sulfate ions.

[0166] Examples of the "organic solvent infinitely soluble in water" that can be added during association and fusion include methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, glycerin, acetone, etc. Among these, alcohols having 3 or less carbon atoms such as methanol, ethanol, 1-propanol, and 2-propanol are preferred, with 2-propanol being particularly preferred.

[0167] When the aggregating agent is added to the dispersion in which the shell resin particles and core particles are dispersed, the temperature of the dispersion is preferably equal to or lower than the glass transition temperature (Tg) of the shell resin particles, specifically, within a range of 5 to 55° C., and more preferably within a range of 10 to 45° C. If the temperature of the dispersion when the aggregating agent is added is equal to or higher than the glass transition temperature (Tg) of the shell resin particles, it becomes difficult to control the particle size, and large particles are likely to be produced.

[0168] The curing agent of the present invention is produced by the above steps.

[0169] [One-component resin composition] 5. Overview FIG. 2 is a conceptual diagram of one example of the one-component resin composition of the present invention. The one-component resin composition PH of the present invention contains a curing agent H and a resin composition P. The resin composition P contains at least a resin. Furthermore, the resin composition P may contain a thermosetting agent to the extent that the functionality of the one-component resin composition PH is not impaired.

[0170] The resin contained in the resin composition P is also called a "binder resin" and is used as a medium or matrix (parent body) for dispersing and retaining the curing agent H, and has the function of adhering to, for example, a fixing member, etc.

[0171] The weight ratio of the curing agent to the resin composition in the one-component resin composition of the present invention is preferably 100:0.1 to 100:1000. The one-component resin composition of the present invention is preferably a liquid at room temperature or a paste having a viscosity of 50 mPa·s to 10,000,000 mPa·s at 25°C. The lower the viscosity, the higher the workability and the lower the amount of adhesion to the container, which makes it possible to reduce waste, which is preferable.

[0172] The one-component resin composition of the present invention can be produced by dispersing the curing agent of the present invention in the resin composition using a three-roll mill or the like.

[0173] In recent years, particularly in the field of electronic devices, one-component resin compositions have been used as a type of connecting material to address the need for higher circuit density and improved connection reliability, to allow the use of materials with low heat resistance in order to reduce the weight of mobile devices, and to significantly improve productivity. These one-component resin compositions are required to have excellent curability while maintaining storage stability.

[0174] The curing agent of the present invention is a latent curing agent that can accelerate the curing reaction at a lower temperature than conventional latent curing agents. Furthermore, when used in combination with a resin composition to form a one-component resin composition, the viscosity increasing rate of the resin composition during the curing reaction increases dramatically, making it suitable for satisfying the above-mentioned requirements.

[0175] 6.Contains ingredients (6.1) Resin The resin is not particularly limited, and conventionally known resins can be used, such as epoxy resins, polyesters, polyurethanes, acrylic resins, polyethers, melamine resins, and modified epoxy resins such as urethane-modified epoxy resins, rubber-modified epoxy resins, and alkyd-modified epoxy resins.

[0176] The epoxy resin may be used in combination with a conventionally known resin, or different resins may be selected from conventionally known resins and used in combination.

[0177] The resin is preferably an epoxy resin from the viewpoints of improving adhesiveness by accelerating the curing reaction and durability against organic solvents, and also from the viewpoint of obtaining a cured product with a low coefficient of thermal expansion (CTE).

[0178] The epoxy resin is preferably a different type of epoxy resin from the type of epoxy resin used in the shell described above.

[0179] (6.2) Heat hardener There are two types of thermosetting agents: those that undergo a curing reaction even at relatively low temperatures and those that do not undergo a curing reaction unless the temperature is high. The preferred thermosetting agent to be contained in the one-component resin composition of the present invention is a thermosetting agent that does not undergo a curing reaction unless the temperature is high.

[0180] Examples of the heat curing agent that exhibits a curing reaction even at a relatively low temperature include aliphatic polyamines, polyaminoamides, and polymercaptans.

[0181] Examples of heat-curing agents that do not undergo a curing reaction unless heated to a high temperature include aromatic polyamines, acid anhydrides, phenol novolac resins, dicyandiamide, etc. By using these, it is possible to obtain a cured product that has high heat resistance, a low thermal expansion coefficient, a high glass transition temperature, and excellent film strength and insulating properties.

[0182] Among the above-mentioned thermosetting agents, acid anhydrides are more preferred because of their high solubility in epoxy resins and reactive diluents. High solubility in resin compositions is preferred from the viewpoints of ejection stability and pot life. Solid materials such as dicyandiamide may precipitate even after dissolving, making it difficult to achieve inkjet suitability, such as ejection stability, when inkjet-ejecting a one-component resin composition, for example. Furthermore, solid materials may require heating to dissolve, which may shorten the pot life of the ink.

[0183] Examples of acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, dodecylsuccinic anhydride, chlorendic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, methylcyclohexenetetracarboxylic anhydride, trimellitic anhydride, and polyazelaic anhydride.

[0184] As the heat curing agent other than the acid anhydride, for example, a modified polyamine compound such as an amine-epoxy adduct may be used, and other heat curing agents may also be used.

[0185] In addition, adducts such as epoxy compound-added polyamines (reaction products of epoxy compounds and polyamines), Michael addition polyamines (reaction products of α,β-unsaturated ketones and polyamines), Mannich addition polyamines (condensates of polyamines with formalin and phenols), thiourea-added polyamines (reaction products of thiourea and polyamines), and ketone-blocked polyamines (reaction products of ketone compounds and polyamines [ketimines]) may also be used.

[0186] The content of the thermosetting agent is preferably in the range of 1 to 60 mass %, more preferably in the range of 5 to 60 mass %, and even more preferably in the range of 5 to 50 mass %, relative to 100 mass % of the one-component resin composition.

[0187] Specifically, for example, when the thermosetting compound is an epoxy resin, the optimal ratio varies depending on the compound used, but it is generally preferable to use 0.8 to 1.2 molar equivalents of thermosetting agent relative to the epoxy equivalent (molecular weight divided by the number of glycidyl groups).

[0188] [Curable composition] 7. Overview The curable composition of the present invention contains the one-component resin composition of the present invention. The curable composition of the present invention is a further improvement of the one-component resin composition of the present invention for specific applications. Therefore, the one-component resin composition is further diluted with a diluent resin composition or the like, and further contains inorganic fillers and other additives as necessary to form the curable composition of the present invention.

[0189] 8.Ingredients (8.1) Resin composition for dilution The diluent resin composition can be the same as the resin composition P contained in the one-component resin composition described above. The diluent resin composition is preferably an epoxy resin. The diluent resin composition may also contain the inorganic filler described below, and may contain the additives described above.

[0190] Fig. 3 is a conceptual diagram of an example of the curable composition of the present invention. The curable composition HPH contains a resin composition Pd diluted with a diluting resin composition (not shown) and a curing agent H. It may also contain an inorganic filler IF and other additives as needed.

[0191] (8.2) Inorganic filler The curable composition of the present invention preferably contains an inorganic filler from the viewpoints of reducing the thermal expansion coefficient and improving the toughness of the cured product.

[0192] Examples include alumina particles, silica particles, strontium titanate particles, zirconia particles, zinc oxide particles, chromium oxide particles, cerium oxide particles, antimony oxide particles, tungsten oxide particles, tin oxide particles, tellurium oxide particles, manganese oxide particles, and boron oxide particles.

[0193] The inorganic filler is preferably subjected to a hydrophobic treatment using a silane coupling agent, a titanium coupling agent, or the like.

[0194] The degree of hydrophobic treatment is not particularly limited, but a methanol wettability in the range of 40 to 95 is preferred. "Methanol wettability" represents the degree of hydrophobicity and is an index for evaluating wettability with methanol. Methanol wettability, i.e., the degree of hydrophobicity, is calculated as follows.

[0195] 0.2 g of the inorganic filler to be measured is weighed and added to 50 ml of distilled water placed in a 200 ml beaker. Methanol is slowly added dropwise from a burette with the tip immersed in the liquid while stirring slowly until the inorganic filler is completely wet. If the amount of methanol required to completely wet the inorganic fine particles is a (ml), the hydrophobicity degree is calculated using the following formula. Formula: Hydrophobicity = [a / (a+50)] x 100

[0196] (8.3) Additives Examples of additives that can be contained in the curable composition of the present invention include diluents, pigments, conductive fine particles, organic particles, lubricants, organic solvents, crystalline alcohols, water, etc. In addition, other additives such as coupling agents, extenders, and reinforcing materials can also be included.

[0197] (diluent) A "diluent" is a colorless, low-viscosity liquid that is added to a substance to reduce its viscosity and make it easier to handle. By adding a diluent to a one-component resin composition, the viscosity of the one-component resin composition can be reduced.

[0198] The purpose of adding a reactive diluent is to lower the viscosity of the one-component resin composition, and it is more preferable to use a monomer with a high glass transition temperature, as this can increase the glass transition temperature of the cured product.

[0199] Diluents include reactive diluents and non-reactive diluents. Reactive diluents include, for example, butyl glycidyl ether, N,N'-glycidyl-o-toluidine, phenyl glycidyl ether, styrene oxide, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. Non-reactive diluents include, for example, dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and petroleum-based solvents.

[0200] (pigment) Examples of pigments include kaolin, aluminum oxide trihydrate, aluminum hydroxide, chalk powder, gypsum, calcium carbonate, antimony trioxide, pentone, silica, aerosol, lithopone, baryte, and titanium dioxide.

[0201] (Conductive fine particles) Examples of conductive fine particles include carbon black, graphite, carbon nanotubes, fullerenes, iron oxide, gold, silver, aluminum powder, iron powder, nickel, copper, zinc, chromium, solder, nano-sized metal crystals, and intermetallic compounds, all of which can be effectively used depending on the application.

[0202] (organic particles) The organic particles may be particles whose main component is an organic material, and examples of such organic particles include homopolymers such as styrene and methyl methacrylate, polystyrene, polymethyl methacrylate, and styrene-methyl methacrylate copolymers. Examples of organic fine particles include spherical fine particles having a number average primary particle diameter of about 10 to 2000 nm.

[0203] (lubricant) The lubricant may be a metal salt of a higher fatty acid, such as a metal salt of stearate, a metal salt of oleate, a metal salt of palmitate, a metal salt of linoleate, or a metal salt of ricinoleate.

[0204] Examples of metal stearates include zinc stearate, aluminum stearate, copper stearate, magnesium stearate, and calcium stearate. Examples of metal oleates include zinc oleate, manganese oleate, iron oleate, copper oleate, and magnesium oleate. Examples of metal palmitates include zinc palmitate, copper palmitate, magnesium palmitate, and calcium palmitate. Examples of metal linoleates include zinc linoleate and calcium linoleate. Examples of metal ricinoleates include zinc ricinoleate and calcium ricinoleate.

[0205] (organic solvent) Examples of organic solvents include those classified into hydrocarbons, ketones, esters, and alcohols.

[0206] Examples of hydrocarbons include benzene, toluene, xylene, cyclohexane, mineral spirits, and naphtha. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of esters include ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ether acetate. Examples of alcohols include methanol, isopropanol, n-butanol, butyl cellosolve, and butyl carbitol.

[0207] The above organic solvents may be used in combination. When forming core particles, it is preferable to remove organic solvents that are reactive with the amine adduct or amine compound by distillation or the like.

[0208] By incorporating an organic solvent inactive to the amine adduct or the amine compound within a specific range, the one-component resin composition has high storage stability without impairing the curability thereof, and the resin composition has excellent fluidity and dispersibility when a curing agent composition is blended therewith.

[0209] However, the content of the organic solvent is preferably kept to 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less, based on 100% by mass of the one-component resin composition.

[0210] (crystalline alcohol) Examples of crystalline alcohols include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, pentaerythritol, sorbitol, sucrose, and trimethylolpropane.

[0211] (water) The water is not particularly limited and may be ion-exchanged water, distilled water, or pure water, but the water content is preferably kept to 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.2% by mass or less, based on 100% by mass of the one-component resin composition.

[0212] (Additive content) The content of the additive is preferably less than 30% by weight. The content of the additive is preferably in the range of 0.05 to 5.0 parts by mass relative to the total mass of the one-component resin composition, from the viewpoints of improving fluidity and homogenizing the components contained in the one-component resin composition, thereby stabilizing the physical properties of the cured product after it is formed.

[0213] 9.Applications The curing agent composition of the present invention can be used in a variety of applications in the form of a paste or film, and is useful, for example, as a sealing material. In addition to adhesives and / or bonding pastes and bonding films, the curing agent composition is also useful as a conductive material, anisotropic conductive material, conductive particles, insulating materials, coating materials, paint compositions, prepregs, thermally conductive materials, and sealing materials for fuel cells.

[0214] (sealant) As the sealing material, it is useful as a solid sealing material, a liquid sealing material, a film sealing material, etc., and as a liquid sealing material, it is useful as an underfill material, a potting material, a dam material, etc.

[0215] Methods for producing the sealing material are described in, for example, Japanese Patent Application Laid-Open Nos. 5-43661 and 2002-226675 as molding materials for sealing and impregnating electric and electronic parts.

[0216] More specifically, a bisphenol A type epoxy resin, a curing agent such as methylhexahydrophthalic anhydride as an acid anhydride curing agent, and spherical fused silica filler powder are added and mixed uniformly, and the curing agent composition obtained according to the present invention is added thereto and mixed uniformly to obtain an encapsulating material.

[0217] The curable composition is suitable for use as a semiconductor sealing material in the above-mentioned sealing material applications. [Example]

[0218] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. In the examples, the terms "parts" and "%" are used, but unless otherwise specified, they represent "parts by mass" or "% by mass."

[0219] [Preparation of hardener] [1] Preparation of hardener [1] [1-1] Preparation of core particle [C1] The following compounds, which are the main components of the core particles, were prepared in the amounts shown below, and reacted at 80°C in a 1 / 1 mixed solvent of n-butanol and toluene (resin content: 50%). <Compounds that are the main components of core particles> Bisphenol A epoxy resin 1.5 equivalents 2-Methylimidazole (amine compound) 1 equivalent (active hydrogen equivalent)

[0220] The bisphenol A type epoxy resin has an epoxy equivalent of 185 g / equivalent and a total chlorine content of 1400 ppm.

[0221] Thereafter, the 2-methylimidazole was distilled off together with the solvent under reduced pressure until the 2-methylimidazole content was reduced to less than 10 ppm, thereby obtaining a solid amine adduct at 25° C. This was designated as core particles [C1].

[0222] [1-2] Preparation of shell resin particle dispersion [S1] (Preparation of Core Resin Particle Dispersion for Shell: First-Stage Polymerization) A 5000 ml separable flask equipped with a stirrer, a temperature sensor, a condenser, and a nitrogen inlet was charged with an aqueous medium [1], a surfactant solution prepared by dissolving 7.08 g of anionic surfactant in 2760 g of ion-exchanged water. The anionic surfactant used was sodium dodecylsulfonate (SDS).

[0223] The aqueous medium [1] was stirred at a stirring speed of 230 rpm under a nitrogen stream, and the internal temperature was raised to 80°C. A polymerization initiator solution [1] prepared by dissolving 0.42 g of a polymerization initiator in 200 g of ion-exchanged water was added to the aqueous medium [1] to prepare a mixed solution of the aqueous medium [1] and the polymerization initiator solution [1]. Potassium persulfate (KPS) was used as the polymerization initiator.

[0224] The temperature of the mixture of the aqueous medium [1] and the polymerization initiator solution [1] was raised to 75°C, and then a monomer mixture consisting of the following polymerizable monomers was added dropwise to the mixture in the following amount over one hour. <Polymerizable monomer> Styrene (aromatic vinyl monomer) 115.1g n-Butyl acrylate 42.0g Methacrylic acid ((meth)acrylic acid ester monomer) 10.9g

[0225] The system was then heated and stirred at 75°C for 2 hours to carry out polymerization (first stage polymerization) to prepare latex [H1].

[0226] (Formation of intermediate layer on core resin particles for shell: second-stage polymerization) In a flask equipped with a stirrer, 72.0 g of exemplary compound (19) was added to a monomer mixture containing the following polymerizable monomers and the following amounts to prepare a mixture of the polymerizable monomers and exemplary compound (1). <Polymerizable monomer> Styrene (aromatic vinyl monomer) 383.6g n-Butyl acrylate 140.0g Methacrylic acid 36.4g n-Octyl-3-mercaptopropionic acid ester (vinyl ester monomer) 5.6g

[0227] [ka]

[0228] The mixed solution of the polymerizable monomer and exemplary compound (19) was heated to 80° C. to dissolve the monomer, and further adjustment was carried out.

[0229] On the other hand, an aqueous medium [2], which is a surfactant solution prepared by dissolving 1.6 g of anionic surfactant in 2000 ml of ion-exchanged water, was heated to 80°C. Sodium dodecyl sulfonate (SDS) was used.

[0230] This aqueous medium [2] and a mixture of the polymerizable monomer and exemplary compound (19) were mixed and dispersed using a mechanical disperser with a circulation path, "CLEARMIX" (manufactured by M Technique Co., Ltd.) to prepare an emulsified dispersion [1] containing emulsified particles (oil droplets) with a uniform dispersed particle size (110 nm).

[0231] On the other hand, the following polymerization initiator solution [2] and 750 ml of ion-exchanged water were added to the latex [H1], and the system was heated to 80°C. The polymerization initiator solution [2] was prepared by dissolving 19.1 g of a polymerization initiator in 240 ml of ion-exchanged water. Potassium persulfate (KPS) was used as the polymerization initiator.

[0232] Thereafter, the emulsion dispersion [1] was added to this system, and polymerization (second-stage polymerization) was carried out by heating and stirring at 80°C for 3 hours to prepare a latex [HM1].

[0233] (Formation of outer layer covering intermediate layer: third polymerization stage) To the latex [HM1] obtained as described above, a polymerization initiator [3] prepared by dissolving 22.8 g of a polymerization initiator in 200 ml of ion-exchanged water was added, and the following mixed solution of polymerizable monomers was added dropwise in the following amounts over 1 hour at a temperature of 80°C. Potassium persulfate (KPS) was used as the polymerization initiator. <Polymerizable monomer> Styrene (aromatic vinyl monomer) 850g n-Butyl acrylate 252g Methacrylic acid ((meth)acrylic acid ester monomer) 98g n-Octyl-3-mercaptopropionic acid ester (vinyl ester monomer) 32g

[0234] After the dropwise addition was completed, the system was heated and stirred for 2 hours to carry out polymerization (third-stage polymerization), and then cooled to 30°C to prepare latex [HML1]. This latex [HML1] was used as shell resin particle dispersion [S1].

[0235] The weight-average molecular weight (Mw) of the composite resin particles having a core-shell structure that constitute the latex [HML1] was 8900. The weight-average particle size of the composite resin particles was 125 nm.

[0236] [1-3] Shell formation on the core particle [C1] (Preparation of core particle dispersion [CC1]) The following core particles [C1], surfactant, and ion-exchanged water were mixed in the amounts shown below, and pre-dispersed for 10 minutes using a homogenizer (ULTRA-TURRAX T50, manufactured by IKA).

[0237] Core particles [C1] (amine adduct) 100 parts by mass Anionic surfactant 15 parts by mass Ion-exchanged water 400 parts by mass

[0238] The "anionic surfactant" mentioned above is sodium dodecylsulfonate (SDS).

[0239] Thereafter, a dispersion treatment was carried out for 30 minutes at a pressure of 245 MPa using a high-pressure impact disperser, Ultimizer (manufactured by Sugino Machine), to prepare an aqueous dispersion of core particles [C1].

[0240] Ion-exchanged water was further added to the aqueous dispersion of the core particles [C1] to adjust the solid content to 15% by mass, and this was designated as a core particle dispersion [CC1].

[0241] The volume-based median diameter (d50) of the core particles in the core particle dispersion [CC1] was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and was found to be 3.1 μm.

[0242] (Shell formation) A mixture of the following dispersion and ion-exchanged water was placed in a reaction vessel equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirrer in the amounts shown below. The mixture was stirred to adjust the internal temperature to 30°C, and a 5N aqueous solution of sodium hydroxide was added to adjust the pH to 11.0 to prepare a mixed dispersion [1] containing core particles and shell resin particles. <Dispersion liquid and ion-exchanged water> Core particle dispersion [CC1] 1800g Shell resin particle dispersion (S1) 3000g Ion-exchanged water 2000g

[0243] Next, an aqueous solution prepared by dissolving 526 g of magnesium chloride hexahydrate in 720 ml of ion-exchanged water was added to the mixed dispersion liquid [1] over 10 minutes at 30°C while stirring, and the mixture was allowed to stand for 3 minutes. After that, the temperature was raised by 10°C per minute, and the system was heated to 90°C over 6 minutes to obtain mixed dispersion liquid [2].

[0244] An aqueous solution was prepared by dissolving 400 g of magnesium chloride in 500 ml of ion-exchanged water, and this aqueous solution was added to the mixed dispersion liquid [2] and stirred for 30 minutes to prepare a mixed dispersion liquid [3].

[0245] An aqueous solution was prepared by dissolving 1150 g of sodium chloride in 7000 ml of ion-exchanged water, and this aqueous solution was added to the mixed dispersion liquid [3] to stop the particle growth of the composite resin particles in the mixed dispersion liquid [3].

[0246] For the aging treatment, the mixed dispersion liquid [3] was heated to a liquid temperature of 85°C and stirred for 2 hours. This allowed the association and fusion of the shells to the core particles [C1] to continue. The liquid temperature and the heating and stirring time during the aging treatment are listed as the reaction conditions for association and fusion in Table I.

[0247] Thereafter, the liquid temperature of the above system was lowered by 8°C per minute to 30°C, hydrochloric acid was added to adjust the pH to 2.0, stirring was stopped, and a dispersion containing fused particles [1] was prepared.

[0248] The fused particles [1] were filtered from the dispersion, washed repeatedly with ion-exchanged water, and then dried with hot air at 40°C to prepare fused particles [1]. These fused particles [1] were used as curing agent [1].

[0249] The volume average particle size of the curing agent [1] was measured using a Coulter Counter TA-II and found to be 3.5 μm.

[0250] [1-4] Confirmation of remaining functional groups The obtained curing agent [1] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When C13 nuclear magnetic resonance spectroscopy of the shell formed on the surface of the core particle [C1] was performed, a peak was observed in the range of 1200 to 1300 cm -1It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C1].

[0251] [2] Preparation of hardeners [2] to [5] The core particles of the curing agents [2] to [5] were designated as core particles [C1], and the shell resin particle dispersion was designated as shell resin particle dispersion [S1].

[0252] In forming the shell on the core particles, the shell was formed in the same manner as in the preparation of curing agent [1], except that the reaction conditions and reaction time during association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of each of curing agents [2] to [5] was measured, and the results are shown in Table I.

[0253] Furthermore, FT-IR measurements were carried out on the obtained curing agents [2] to [5]. For the FT-IR measurements, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When C13 nuclear magnetic resonance spectroscopy was carried out on the shell formed on the surface of the core particle [C1], a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C1] of each of the curing agents [2] to [5].

[0254] [3] Preparation of hardener [6] [3-1] Core particle The core particles of the curing agent [6] were designated as core particles [C1]. The dispersion of shell resin particles was prepared as follows.

[0255] [3-2] Preparation of shell resin particle dispersion [S2] (Preparation of amorphous polyester particles [a1]) Into a reaction vessel equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet tube, the following monomer [1] and 0.25 parts by mass of "tin dioctylate" per 100 parts by mass of the total of the following monomer [1] were added. <Monomer [1]> Bisphenol A ethylene oxide 2.2 mole adduct 40 mole parts Bisphenol A propylene oxide 2.2 mole adduct 60 mole parts Dimethyl terephthalate 60 parts by mole Dodecenyl succinic anhydride 20 mole parts

[0256] The reaction was carried out in a reaction vessel at 235° C. for 6 hours under a nitrogen gas stream.

[0257] Thereafter, the temperature inside the reaction vessel was lowered to 200° C., and 15 parts by mole of dimethyl fumarate and 5 parts by mole of trimellitic anhydride were added to the reaction vessel, and the mixture was allowed to react in the reaction vessel for 1 hour.

[0258] The temperature inside the reaction vessel was raised to 220° C. over 5 hours, and polymerization was carried out under a pressure of 10 kPa until the desired molecular weight was reached, producing pale yellow, transparent amorphous polyester particles [a1].

[0259] The amorphous polyester particles [a1] had a weight average molecular weight (Mw) of 35,000, a number average molecular weight (Mn) of 8,000, and a glass transition temperature (Tg) of 56°C.

[0260] (Preparation of Dispersion Containing Amorphous Polyester Particles [a1]) Next, the amorphous polyester particles [a1] and the following mixed solution [2] were placed in a separable flask in the amounts shown below, and thoroughly mixed to dissolve. Amorphous polyester particles [a1] 200.0 parts by mass <Mixed solution [2]> Methyl ethyl ketone 100.0 parts by mass Isopropyl alcohol 35.0 parts by mass 10% by mass ammonia aqueous solution 7.0 parts by mass

[0261] Thereafter, ion-exchanged water was added dropwise to the separable flask at a rate of 8 g / min using a pump while the contents were heated and stirred at 40° C. When the amount of ion-exchanged water reached 580 parts by mass, the addition of ion-exchanged water was stopped to prepare a dispersion containing amorphous polyester particles [a1]. Thereafter, the solvent was removed under reduced pressure to prepare another dispersion.

[0262] Ion-exchanged water was added to the dispersion liquid so that the solid content was adjusted to 25% by mass, thereby obtaining a shell resin particle dispersion liquid [S2] containing amorphous polyester particles [a1].

[0263] The volume-based median diameter (d50) of the amorphous polyester particles [a1] was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and was found to be 156 nm.

[0264] [3-3] Shell formation on core particles The core particle dispersion was prepared in the same manner as in the preparation of curing agent [1]. In the formation of the shell, the shell resin particle dispersion [S1] was changed to the shell resin particle dispersion [S2], and the reaction conditions for association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of curing agent [6] was measured at this time, and the results are shown in Table I.

[0265] Furthermore, the obtained curing agent [6] was subjected to FT-IR measurement, and the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C1] of the curing agent [6] was measured. -1 It was confirmed that there was no absorption at 1000 kJ / cm2. This confirmed that there was no secondary amine and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C1] of the curing agent [6].

[0266] [4] Preparation of hardener [7] [4-1] Core particle The core particles were designated as core particles [C1]. The dispersion of shell resin particles was prepared as follows.

[0267] [4-2] Preparation of shell resin particle dispersion [S3] (Preparation of crystalline polyester particles [c1]) The following monomer [4] was placed in the following amounts in a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet tube, and the atmosphere in the reaction vessel was replaced with dry nitrogen gas.

[0268] <Monomer [4]> Dodecanedioic acid 50 mole parts 1,6-Hexanediol 50 mole parts

[0269] Next, 0.25 parts by mass of titanium tetrabutoxide (Ti(On-Bu)4) was added relative to a total of 100 parts by mass of the above monomer [4]. Under a nitrogen gas flow, the temperature inside the reaction vessel was raised to 170°C, and the mixture was stirred and reacted for 3 hours. Thereafter, the temperature inside the reaction vessel was further raised to 210°C over 1 hour, the pressure inside the reaction vessel was reduced to 3 kPa, and the mixture was stirred and reacted under reduced pressure for 13 hours.

[0270] In this way, crystalline polyester particles [c1] were prepared.

[0271] The crystalline polyester particles [c1] had a weight average molecular weight (Mw) of 25,000, a number average molecular weight (Mn) of 8,500, and a melting point of 71.8°C.

[0272] (Preparation of dispersion containing crystalline polyester particles [c1]) Next, the crystalline polyester particles [c1] and a mixed solution consisting of the following mixed solution [5] were placed in a separable flask in the amounts shown below, and the mixture was thoroughly mixed and dissolved at 70°C. After that, 8 parts by mass of a 10% by mass aqueous ammonia solution was added dropwise. Crystalline polyester [c1] 200 parts by mass <Mixed solution [5]> Methyl ethyl ketone 120 parts by mass Isopropyl alcohol 30 parts by mass

[0273] Thereafter, the heating temperature was lowered to 67°C, and ion-exchanged water was added dropwise at a rate of 8 g / min using a pump while stirring. When the amount of ion-exchanged water fed reached 580 parts by mass, the addition of ion-exchanged water was stopped to prepare a dispersion containing crystalline polyester particles [c1]. Thereafter, the solvent was removed under reduced pressure to prepare another dispersion.

[0274] Ion-exchanged water was added to the dispersion liquid so that the solid content was adjusted to 25% by mass, thereby obtaining a shell resin particle dispersion liquid [S3] containing crystalline polyester particles [c1].

[0275] The volume-based median diameter (d50) of the crystalline polyester particles [c1] was measured using Microtrac UPA-150 (manufactured by Nikkiso Co., Ltd.) and was found to be 198 nm.

[0276] [4-3] Shell formation on core particles The core particle dispersion was prepared in the same manner as in the preparation of curing agent [1]. In the formation of the shell, the shell resin particle dispersion [S1] was changed to the shell resin particle dispersion [S3], and the reaction conditions for association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of curing agent [7] was measured at this time, and the results are shown in Table I.

[0277] The obtained curing agent [7] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C1] was measured, a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C1] of the curing agent [7].

[0278] [5] Preparation of hardener [8] [5-1] Core particle and shell resin particle dispersion The core particles were designated as core particles [C1], and the shell resin particle dispersion was designated as shell resin particle dispersion [S1].

[0279] [5-2] Shell formation on core particles (Preparation of core particle dispersion [CC8]) A surfactant solution in a solvent medium was prepared by dissolving 90 g of polyoxyethylene (6) lauryl ether, a nonionic surfactant, in 1600 ml of xylene.

[0280] The above surfactant solution and the following components were charged in the amounts shown below into a reaction vessel equipped with a temperature sensor, a cooling tube, a nitrogen introducing device, and a stirrer. The internal temperature was adjusted to 30°C, and the mixture was stirred for 10 minutes to prepare a core particle dispersion liquid [CC8]. <Ingredients> Core particles (C1) 6000g 2000g xylene

[0281] (Shell formation) The core particle dispersion liquid [CC8] was heated to 80°C over 6 minutes, and then 1000 g of the shell resin particle dispersion liquid [S1] was added to the heated core particle dispersion liquid [CC8] and stirred for 30 minutes.

[0282] Further, as a maturation treatment, the mixture was heated and stirred at a liquid temperature of 85° C. for 2 hours, thereby allowing the association and fusion of the shell to the core particles to continue.

[0283] Thereafter, the liquid temperature of the above system was lowered by 8°C per minute to 30°C, and stirring was stopped to prepare a dispersion liquid.

[0284] The fused particles [8] were filtered from the dispersion, washed repeatedly with xylene, and then dried with hot air at 60°C to prepare fused particles [8]. The fused particles [8] were used as the curing agent [8].

[0285] At this time, the volume average particle diameter of the curing agent [8] was measured, and the results are shown in Table I.

[0286] The obtained curing agent [8] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C1] was measured, a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C1] of the curing agent [8].

[0287] [6] Preparation of hardener [9] [6-1] Preparation of core particle [C9] 6000 g of core particles [C1] were coarsely pulverized using a cutter mill. Further, they were finely pulverized using a jet mill, a high-speed rotary pulverizer, or other pulverizer to produce a microparticle adduct [C9] by the pulverization method. The average particle size of the microparticle adduct [C9] was 0.22 μm. This microparticle adduct [C9] was used as the core particle [C9] of the curing agent [9].

[0288] [6-2] Shell resin particle dispersion The shell resin particle dispersion was named shell resin particle dispersion [S1].

[0289] [6-3] Shell formation on core particles The preparation of the core particle dispersion was carried out in the same manner as for the preparation of curing agent [1], except that core particles [C9] were used as the core particles. In the formation of the shell, curing agent [9] was prepared in the same manner as for curing agent [1], except that the reaction conditions during association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of curing agent [9] was measured at this time, and the results are shown in Table I.

[0290] The obtained curing agent [9] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C9] was measured, a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C9] of the curing agent [9].

[0291] [7] Preparation of hardener

[10] As the hardener

[10] , a hardener identical to the hardener [1] was prepared.

[0292] [8] Preparation of hardener

[11] [8-1] Preparation of core particle [C11] The following compounds, which are the main components of the core particles, were prepared in the amounts shown below, and were pulverized using a cutter mill as a pulverizer. <Compounds that are the main components of core particles> 2-Methylimidazole 1 equivalent (active hydrogen equivalent)

[0293] These particles are designated as core particles [C11]. The average particle size of the core particles [C11] was 3.20 μm.

[0294] [8-2] Shell resin particle dispersion The shell resin particle dispersion was named shell resin particle dispersion [S1].

[0295] [8-3] Shell formation on core particles The preparation of the core particle dispersion was carried out in the same manner as for the preparation of curing agent [1], except that core particles [C11] were used as the core particles. In the formation of the shell, curing agent

[11] was prepared in the same manner as for curing agent [1], except that the reaction conditions during association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of curing agent

[11] was measured at this time, and the results are shown in Table I.

[0296] The obtained curing agent

[11] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C11] was measured, a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C11] of the curing agent

[11] .

[0297] [9] Preparation of hardener

[12] [9-1] Preparation of core particle [C12] The following compounds, which are the main components of the core particles, were prepared in the amounts shown below, and were pulverized using a cutter mill as a pulverizer. <Compounds that are the main components of core particles> 4,4'-methylenedianiline 1 equivalent (active hydrogen equivalent)

[0298] These particles are referred to as core particles [C12]. The average particle size of the core particles [C12] was 3.30 μm.

[0299] [9-2] Shell resin particle dispersion The shell resin particle dispersion was named shell resin particle dispersion [S1].

[0300] [9-3] Shell formation on core particles The preparation of the core particle dispersion was carried out in the same manner as for the preparation of curing agent [1], except that core particles [C12] were used as the core particles. In the formation of the shell, curing agent

[12] was prepared in the same manner as for curing agent [1], except that the reaction conditions during association and fusion were changed as shown in Table I. In addition, the volume average particle diameter of curing agent

[12] was measured at this time, and the results are shown in Table I.

[0301] The obtained curing agent

[12] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C12] was measured, a peak was observed in the range of 1200 to 1300 cm -1 It was confirmed that the shell had no absorption spectrum in the absorption wavelength range within this range. This confirmed that there were no secondary amines and no residual functional groups in the shell. This confirmed that the shell was not chemically bonded to the core particle [C12] of the curing agent

[12] .

[0302]

[10] Preparation of hardener

[13] [10-1] Core particle 100 parts by mass of core particles [C1] were heated and melted, 2-methylimidazole was mixed uniformly, and the mixture was cooled to room temperature and then pulverized to prepare solid core particles [C13] at 25° C. At this time, the amount of 2-methylimidazole contained in the core particles [C13] was 0.9 parts by mass.

[0303] [10-2] Shell formation on core particles The following materials were mixed in the amounts shown below, and the reaction was continued for 3 hours at 40°C with stirring. <Material> Bisphenol A epoxy resin 200 parts by mass Core particles [C13] 100 parts by mass Ion-exchanged water 1.5 parts by mass Tolylene diisocyanate 7 parts by mass

[0304] Thereafter, the shell-forming reaction was carried out at 50°C for 8 hours, and the solvent was removed using xylene to prepare the curing agent

[13] .

[0305] The volume average particle size of the curing agent

[13] was measured using a Coulter Counter TA-II and found to be 3.4 μm.

[0306] [10-3] Confirmation of remaining functional groups The obtained curing agent

[13] was subjected to FT-IR measurement. For the FT-IR measurement, an infrared spectrophotometer "IRT-5200" (manufactured by JASCO Corporation) was used. When the C13 nuclear magnetic resonance spectrum of the shell formed on the surface of the core particle [C13] was measured, a peak was observed in the range of 1200 to 1400 cm -1 It was confirmed that the shell has an absorption spectrum in the absorption wavelength range within this range. This confirmed the presence of tertiary amines and secondary amines, and the presence of residual functional groups in the shell. It is believed that the residual protons affect the dielectric constant evaluation described below. This confirmed that the shell is chemically bonded to the core particle [C13].

[0307] [Table 1]

[0308] [Preparation of one-component resin composition] The following materials were mixed in the amounts shown below to prepare a one-component resin composition [Pa1]. <Material> Hardener [1] 30 parts Bisphenol A epoxy resin 100 parts HN-2200 100 copies

[0309] The above-mentioned "HN-2200" is manufactured by Hitachi Chemical Co., Ltd., and its main component is phthalic anhydride.

[0310] The curing agent [1] was changed as shown in Table II to prepare one-component resin compositions [Pa2] to [Pa13].

[0311] [A] Storage stability (Evaluation method) The one-component resin compositions [Pa1] to [Pa13] were stored at 50°C for one week to prepare the one-component resin compositions [PA1] to [PA13].

[0312] The viscosity ratio of each of the one-component resin compositions [PA1] to [PA13] was calculated by the following formula, and the storage stability of each of the one-component resin compositions [PA1] to [PA13] was evaluated according to the following evaluation criteria. The results are shown in Table II. The viscosity was measured at 25°C using a BM type viscometer. Formula: Viscosity multiplier = viscosity after 1 week of storage / viscosity before 1 week of storage [times]

[0313] (Evaluation criteria) A: The calculated viscosity multiplier is less than 1.5 times. B: The calculated viscosity multiplier is 1.5 times or more and less than 2 times. C: The calculated viscosity multiplier is 2 times or more.

[0314] [Table 2]

[0315] [B] Storage stability when heated (Evaluation method) The one-component resin compositions [Pa1] to [Pa13] were kept at a constant temperature of 30°C and a humidity of 85% for 6 hours to produce one-component resin compositions [Pb1] to [Pb13].The one-component resin compositions [Pb1] to [Pb13] were then stored at 40°C and a humidity of 50% for one week to produce one-component resin compositions [PB1] to [PB13].

[0316] The viscosity ratios of the one-component resin compositions [PB1] to [PB13] were calculated using the following formula, and the storage stability under heating of the one-component resin compositions [PB1] to [PB13] was evaluated according to the following criteria. The results are shown in Table III. The viscosity was measured at 25°C using a BM type viscometer. Formula: Viscosity multiplier = Viscosity after 1 week storage / Viscosity after 6 hours storage before 1 week storage [times]

[0317] (Evaluation criteria) A: The calculated viscosity multiplier is less than 2 times. B: The calculated viscosity multiplier is 2 times or more and less than 5 times. C: The calculated viscosity multiplier is 5 times or more.

[0318] [Table 3]

[0319] [C] Measurement of shear adhesive strength Test pieces [PC1] to [PC13] of the one-component resin composition were prepared in accordance with JIS K6850 using the one-component resin compositions [Pa1] to [Pa13]. The one-component resin composition test piece [PC1] was cured at 120°C for 1 hour, and the maximum load [kg / cm] until the test piece broke was measured. 2 For the measurement, adherends conforming to JIS G3141, measuring 25 mm wide x 100 mm long x 1.6 mm thick, were used.

[0320] The shear adhesive strength of the test pieces [PC1] to [PC13] of the one-component resin composition is specifically shown in Table IV as the maximum load [kg / cm 2 ] was written.

[0321] [Table 4]

[0322] [Preparation of curable composition] The following materials were charged in the amounts shown below and stirred at room temperature of 25°C to prepare a curable composition [1]. <Material> One-component resin composition [Pa1] 18 parts by mass Methyltetrahydroxy acid anhydride (acid anhydride equivalent 164g / eq) 18 parts by mass Fused spherical silica (average particle size 35μm) 78 parts by mass 3-Glycidoxypropyltrimethoxysilane (silane coupling agent) 3 parts by mass Carbon black 1 part by mass

[0323] Curable compositions [2] to

[13] were prepared in the same manner as curable composition [1], except that the one-component resin composition [Pa1] was changed as shown in Table V. In addition, curable composition

[14] was prepared in the same manner as curable composition [1], except that the one-component resin composition [Pa1] was used as is and fused spherical silica (average particle size 35 μm) was not added.

[0324] [D] Gel time measurement Each of the curable compositions [1] to

[14] was placed in an amount of 0.5 g on a hot plate heated to 120°C, and was spread uniformly in a circle within a range of 2.0 to 2.5 cm using a jig at a rotation speed of 20 to 25 rotations per minute.

[0325] As described above, the curable compositions [1] to

[14] were placed on the hot plate, and the time until the viscosity of each of the curable compositions [1] to

[14] disappeared, they became gelled, and they could be peeled off from the hot plate was measured, and this time was measured as the gel time (seconds). The results are shown in Table V. The shorter the gel time, the better the curability.

[0326] [E] Crack evaluation Figure 4 is a simplified diagram showing an example of how a molded product is produced by compression molding. A film F1 was placed in advance in the cavity 2 of the lower mold part 4 of the compression molding system shown in Figure 4, and each curable composition HPH was applied to the film F1. An FR-4 substrate 1 containing a silicon chip substrate SI was then pressed into the lower mold part 4 by the upper mold part 3, and the resulting product was heated at 120°C for 3 minutes. The cavity 2 and FR-4 substrate 1 were as follows: Resonac's "RM-4170" was used as the film F1. Cavity (100 x 100 x 0.3 mm) FR-4 board (120 x 120 x 0.4 mm)

[0327] The molded products F2 produced using the curable compositions [1] to

[14] were visually inspected for the presence or absence of cracks. The results are shown in Table V.

[0328] [F] Peelability The film F1 was peeled off from each of the molded products F2. At this time, whether or not each curable composition remained on the peeled film F1 side, that is, whether or not there was adhesion to the peeled film F1, was visually observed. When there was no adhesion, it was judged that releasability was present, and when there was adhesion, it was judged that releasability was absent. The results are shown in Table V.

[0329] [G] Measurement of relative permittivity Dk and dielectric loss tangent Df Curable compositions [1] to

[14] were loaded into a vacuum hand press and molded under conditions of a mold temperature of 175°C, a molding pressure of 6.9 MPa, and a cure time of 600 seconds. Post-curing was carried out at 180°C for 6 hours to obtain a plate-shaped cured product (12.5 mm long, 25 mm wide, and 0.2 mm thick). This plate-shaped cured product was used as a test specimen to measure the relative permittivity Dk and dielectric loss tangent Df at approximately 60 GHz at a temperature of 25±3°C using an Agilent Technologies Network Analyzer N5227A. The measurement results are shown in Table V.

[0330] [Table 5]

[0331] [Overall Review] As is clear from Tables I to V, the curing agent, one-component resin composition, and curable composition of the present invention have higher productivity and can impart good adhesion compared to the comparative examples.

[0332] While embodiments of the present invention have been described and illustrated in detail above, the disclosed embodiments are made for purposes of illustration and example only, and not limitation, and the scope of the invention should be construed in terms of the appended claims. [Explanation of symbols]

[0333] H hardener C core particle S shell PH one-component resin composition P resin composition HPH curable composition Resin composition diluted with Pd diluent resin composition IF inorganic filler SI Silicon substrate F1 Film F2 molded product 1 FR-substrate 2 cavities 3 Compression molding upper mold 4. Compression molding lower die

Claims

1. A curing agent having a core-shell structure, the core-shell structure is a structure constituted by a core particle containing an amine adduct or an amine compound as a main component and a shell covering the core particle, the amine adduct is a compound having an amino group produced by a reaction between an amine compound and at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and The shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer. A curing agent characterized by:

2. A composition containing the curing agent according to claim 1 and a resin composition. A one-component resin composition characterized by:

3. The resin composition contains an epoxy resin. The one-component resin composition according to claim 2 .

4. A composition containing the one-component resin composition according to claim 2. A curable composition characterized by:

5. Contains inorganic filler The curable composition according to claim 4 .

6. It is a semiconductor sealing material. The curable composition according to claim 4 .

7. A method for producing a curing agent having a core-shell structure, comprising the steps of: the core-shell structure is a structure constituted by a core particle containing an amine adduct or an amine compound as a main component and a shell covering the core particle, forming the core particles; and forming the shell by associating and fusing a resin onto the surface of the core particle, the amine adduct is a compound having an amino group produced by a reaction between an amine compound and at least one compound selected from the group consisting of an epoxy resin, a carboxylic acid compound, a sulfonic acid compound, a urea compound, and an isocyanate compound, and The shell is a copolymer composed of at least one monomer selected from the group consisting of an aromatic vinyl monomer, a (meth)acrylic acid ester monomer, a vinyl ester monomer, a vinyl ether monomer, a monoolefin monomer, a diolefin monomer, and a halogenated olefin monomer. A method for producing a curing agent comprising the steps of:

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