An epoxy resin curing agent, an epoxy resin composition, a sealing material, a conductive material, a thermally conductive material, an adhesive for camera modules, an adhesive for structures, a matrix resin for fiber-reinforced plastics, an impregnated fixing material, an interlayer insulating film, a film-type solder resist, a sealing sheet, a conductive film, and an anisotropic conductive film. Thermally conductive film and method for producing dyed cured product

Abstract

The epoxy resin curing agent has a core (A) containing a nitrogen-containing compound and a layer (B) covering the core (A), and when the epoxy resin curing agent is dyed with ruthenium tetroxide and osmium tetroxide and then observed with a transmission electron microscope and a brightness graph is obtained by image processing, the layer (B) contains a region having a brightness [alpha]. The luminance alpha is higher than the luminance beta of the outermost portion of the layer (B) and the luminance gamma of the boundary between the layer (B) and the core (A).

Description

Technical Field

[0001] The present invention relates to an epoxy resin curing agent, an epoxy resin composition, a sealing material, a conductive material, a thermally conductive material, an adhesive for a camera module, an adhesive for a structure, a matrix resin for fiber-reinforced plastics, an impregnation fixing material, an interlayer insulating film, a film-type solder resist, a sealing sheet, a conductive film, an anisotropic conductive film, a thermally conductive film, and a method for producing a dyed cured product. Background Art

[0002] Epoxy resins are used in a wide range of applications, such as insulating materials for semiconductor packages, camera modules and other electrical and electronic parts, sealing materials, adhesives, conductive materials, matrix resins for fiber-reinforced plastics, impregnation fixing agents for motor coils, adhesives for automobile structures, etc., in the form of epoxy resin compositions containing epoxy resin curing agents.

[0003] In recent years, thin film materials such as bottom filling materials for protecting the protruding connection parts and the circuit surface of the chip, chip bonding films for chip bonding, films for forming interlayer insulation layers, and films for forming solder resist layers are used in semiconductor packages. As the above-mentioned bottom filling materials and various thin film materials, the above-mentioned epoxy resin composition is used.

[0004] As an epoxy resin composition applicable to an underfill material, an epoxy resin composition including a microcapsule type curing agent is disclosed (for example, see Patent Document 1). In addition, as an epoxy resin composition applicable to a film material, an epoxy resin composition including a microcapsule type curing agent is disclosed (for example, see Patent Document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-31227

[0008] Patent Document 2: Japanese Patent Application Publication No. 2017-95570 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] Epoxy resin composition can be used for various purposes as described above, and the components in the composition are appropriately selected according to each purpose. As an optional typical composition system, for example, in the bottom filling material application, an epoxy resin composition comprising a low molecular epoxy compound as a reactive diluent can be cited. In the film material application, an epoxy resin composition comprising solvents such as methyl ethyl ketone (MEK) and cyclohexanone when preparing varnish can be cited. In the dual-curing adhesive application that is cured by both light and heat, an epoxy resin composition comprising a low molecular acrylic compound can be cited. As an epoxy resin curing agent, it is necessary to be able to give storage stability and reactive epoxy resin curing agents in various composition systems as above.

[0011] In addition, when epoxy resin composition includes filler (filler), the cured product formed by curing the epoxy resin composition needs to have excellent appearance, that is, the appearance of the filler uniformly dispersed in the cured product. In recent years, with the high functionality of electronic materials, it is sought to make the micro-region have an excellent appearance than in the past. In other words, filler aggregates and curing agent aggregates that can be evaluated as smaller sizes in the previous level are sometimes regarded as having problems in appearance in recent years.

[0012] The microcapsule-type curing agent and the epoxy resin composition containing the microcapsule-type curing agent disclosed in Patent Documents 1 and 2 still have room for improvement from the above viewpoints.

[0013] An object of the present invention is to provide an epoxy resin curing agent or the like which can impart excellent stability and reactivity to an epoxy resin composition mixed with a low molecular weight epoxy compound, a solvent or a low molecular weight acrylic compound, and can impart excellent appearance even to a micro region when curing an epoxy resin composition containing a filler.

[0014] Solutions for solving problems

[0015] As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by an epoxy resin curing agent having a predetermined structure, thereby completing the present invention.

[0016] That is, the present invention includes the following aspects.

[0017] [1] An epoxy resin curing agent having:

[0018] A core (A) comprising a nitrogen-containing compound, and

[0019] a layer (B) covering the core (A),

[0020] When the epoxy resin curing agent is stained with ruthenium tetroxide and osmium tetroxide and then observed with a transmission electron microscope and a brightness curve diagram is obtained by image processing, the interior of the layer (B) contains a region with brightness α, and the brightness α is higher than the brightness β of the outermost portion of the layer (B) and the brightness γ of the boundary between the layer (B) and the core (A).

[0021] [2] The epoxy resin curing agent according to [1], wherein the core (A) contains 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300.

[0022] [3] The epoxy resin curing agent according to [1] or [2], wherein the core (A) comprises at least one selected from the group consisting of imidazoles, aliphatic amine compounds, and cyclic amine compounds including tertiary amines.

[0023] [4] The epoxy resin curing agent according to any one of [1] to [3], wherein the core (A) comprises an imidazole-based amine-adduct compound.

[0024] [5] The epoxy resin curing agent according to any one of [1] to [4], wherein the particle size D at which the cumulative percentage under the sieve of the core (A) is 50% 50 More than 0.3 μm and less than 12 μm.

[0025] [6] The epoxy resin curing agent according to [5], wherein the particle size D of the core (A) having a cumulative percentage under sieve of 99% 99 With the above D 50 The ratio of D 99 / D 50 Counted as 8 or less.

[0026] [7] The epoxy resin curing agent according to [5] or [6], wherein the specific surface area value Y (m 2 / g) multiplied by the above D 50 The value obtained by measuring the relative humidity (μm) is 3.0 or more and 9.0 or less.

[0027] [8] The epoxy resin curing agent according to any one of [5] to [7], wherein the specific surface area value Y (m 2 / g) multiplied by the above D 50 The value obtained by measuring (μm) is more than 9.0 and less than 18.0.

[0028] [9] An epoxy resin composition comprising the epoxy resin curing agent according to any one of [1] to [8] and an epoxy resin (C).

[0029]

[10] The epoxy resin composition according to [9], wherein the mass ratio of the epoxy resin curing agent to the epoxy resin (C) is 0.1:100 to 1000:100 (epoxy resin curing agent:epoxy resin (C)).

[0030]

[11] The epoxy resin composition according to [9] or

[10] , further comprising an alcohol compound (D) represented by the following formula (1).

[0031]

[0032] (In formula (1), X1 represents an alkylene group having 2 or more and 5 or less carbon atoms which may have a substituent R, and the substituents R and R1 to R5 each independently represent a hydrogen atom, an alkyl group, an unsaturated aliphatic group, an aromatic group, a substituent containing a heteroatom, or a halogen atom, and any of R1 to R5 may constitute a condensed ring compound in which the same ring is formed.)

[0033]

[12] The epoxy resin composition according to

[11] , wherein the content of the alcohol compound (D) is 0.0001% by mass or more and 5% by mass or less relative to the total amount of the epoxy resin composition.

[0034]

[13] The epoxy resin composition according to

[11] or

[12] , wherein the alcohol compound (D) comprises at least one selected from the group consisting of 3-phenoxy-1-propanol, 3-phenoxy-1,2-propanediol, 3-phenoxy-1,3-propanediol, 3-(o-tolyloxy)-1,2-propanediol, 3-(2-methoxyphenoxy)propane-1,2-diol, bisphenol A (3-hydroxypropyl) glycidyl ether and bisphenol A (2,3-dihydroxypropyl) glycidyl ether.

[0035]

[14] The epoxy resin composition according to any one of [9] to

[13] , wherein the core (A) contains 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300, and the amine compound (a) contains at least one selected from the group consisting of imidazoles, aliphatic amine compounds and cyclic amine compounds containing tertiary amines.

[0036]

[15] A sealing material comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0037]

[16] A conductive material comprising the epoxy resin curing agent according to any one of [1] to [8] or the epoxy resin composition according to any one of [9] to

[14] .

[0038]

[17] A thermally conductive material comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0039]

[18] An insulating material comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0040]

[19] An adhesive for a camera module, comprising the epoxy resin curing agent according to any one of [1] to [8] or the epoxy resin composition according to any one of [9] to

[14] .

[0041]

[20] A structural adhesive comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0042]

[21] A matrix resin for fiber-reinforced plastics, comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0043]

[22] An impregnation fixing material comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0044]

[23] An interlayer insulating film comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0045]

[24] A thin film solder resist comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0046]

[25] A sealing sheet comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0047]

[26] A conductive film comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0048]

[27] An anisotropic conductive film comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0049]

[28] A thermally conductive film comprising the epoxy resin curing agent described in any one of [1] to [8] or the epoxy resin composition described in any one of [9] to

[14] .

[0050]

[29] A method for producing a dyed cured product, comprising the following steps: a step of electronically dyeing an epoxy resin curing agent having a core (A) and a layer (B) covering the core (A) with ruthenium tetroxide (S1);

[0051] A step (S2) of obtaining a cured product of the composition containing the epoxy resin curing agent that has undergone the step (S1); and

[0052] A step (S3) of electron staining the slice of the solidified product with osmium tetroxide.

[0053] Effects of the Invention

[0054] According to the present invention, an epoxy resin curing agent or the like can be provided which imparts excellent stability and reactivity to an epoxy resin composition mixed with a low molecular weight epoxy compound, a solvent or a low molecular weight acrylic compound, and can also impart excellent appearance to a micro region when curing an epoxy resin composition containing a filler. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is an edited image obtained by drawing lines at predetermined positions in an image obtained by performing image analysis on a TEM observation image of the epoxy resin hardener 1 of Example 1 in order to confirm the dyeing property.

[0056] Figure 2 For along Figure 1 A graph in which the brightness of each position is plotted by the line segments in the image.

[0057] Figure 3 This is an edited image obtained by drawing lines at predetermined positions in an image obtained by performing image analysis on a TEM observation image of the epoxy resin hardener 3 of Example 3 in order to confirm the dyeing property.

[0058] Figure 4 For along Figure 3 A graph in which the brightness of each position is plotted by the line segments in the image.

[0059] Figure 5 This is an edited image obtained by drawing lines at predetermined positions in an image obtained by performing image analysis on a TEM observation image of the epoxy resin hardener 4 of Example 4 in order to confirm the dyeing property.

[0060] Figure 6 For along Figure 5 A graph in which the brightness of each position is plotted by the line segments in the image.

[0061] Figure 7 This is an edited image obtained by drawing lines at predetermined positions in an image obtained by image analysis of the TEM observation image of the epoxy resin hardener R-1 of Comparative Example 1 in order to confirm the dyeing property.

[0062] Figure 8 For along Figure 7 A graph in which the brightness of each position is plotted by the line segments in the image.

[0063] Fig. 9 These are images showing the results of the appearance evaluation of the micro region in Example 1.

[0064] Fig.10 The images show the results of the appearance evaluation of the micro region in Comparative Example 1. DETAILED DESCRIPTION

[0065] The following is a detailed description of the mode for implementing the present invention (hereinafter also referred to as "this embodiment"). The following this embodiment is an example for illustrating the present invention and is not intended to limit the present invention to the following content. The present invention can be implemented by appropriately modifying it within the scope of its purpose.

[0066] 〔Epoxy resin curing agent〕

[0067] The epoxy resin curing agent of the present embodiment comprises: a core (A) containing a nitrogen-containing compound and a layer (B) covering the core (A), and when the epoxy resin curing agent is stained with ruthenium tetroxide and osmium tetroxide and observed with a transmission electron microscope (hereinafter also referred to as "TEM") and a brightness curve obtained by image processing, the inside of the layer (B) contains a region having a brightness α, and the brightness α is higher than the brightness β of the outermost portion of the layer (B) and the brightness γ of the boundary between the layer (B) and the core (A) (hereinafter, the layer (B) having the above region is also referred to as "having the desired dyeing property"). Since the epoxy resin curing agent of the present embodiment is constructed as described above, when it is mixed with a low molecular weight epoxy compound, a solvent or a low molecular weight acrylic compound to form an epoxy resin composition, it can impart excellent stability and reactivity, and when it is formed into an epoxy resin composition containing a filler and cured, it can also impart excellent appearance to a micro region.

[0068] In this embodiment, it is sufficient that at least a portion of the epoxy resin curing agent has the desired dyeing property, and the more regions having the desired dyeing property, the more preferably. In addition, it is particularly preferred that the entire region of the epoxy resin curing agent has the desired dyeing property.

[0069] (Staining method and TEM observation)

[0070] The dyeing method of the epoxy resin curing agent of the present embodiment and the observation method after dyeing are described below. First, 10.6 mL of the main agent (Quetol 812, manufactured by Nissin EM Co., Ltd.), 9.4 mL of the curing agent (methylnadic anhydride: MNA, manufactured by Nissin EM Co., Ltd.) and 0.34 mL of the reaction accelerator (2,4,6-tris(dimethylaminomethyl)phenol, manufactured by Nissin EM Co., Ltd.: DMP-30) are mixed, and after stirring with a stirrer for 15 minutes, bubbles are removed by vacuum degassing to obtain an epoxy resin composition for dyeing. Next, the epoxy resin curing agent of the present embodiment is made to coexist with ruthenium tetroxide for 10 minutes in a sealed and light-shielded container at room temperature and atmospheric pressure and electronically dyed, mixed with the above-mentioned dyeing epoxy resin composition and cured at 40°C for 42 hours, after the cured product embedded with the epoxy resin curing agent obtained by curing is made into 80nm slices with an ultrathin slicer, the above-mentioned slices are made to coexist with osmium tetroxide for 2 hours in a sealed and light-shielded container at room temperature and atmospheric pressure, and an observation sample electronically dyed with osmium tetroxide vapor is obtained, and an electron beam is irradiated to the above-mentioned observation sample by TEM, and the focus is adjusted to align with the sample, and observed at an accelerating voltage of 120kV and a magnification of 30000 times to obtain a TEM observation image. About these operations, more specifically, the method described in the embodiment described later can be implemented.

[0071] (Brightness curve of layer (B) obtained by image processing)

[0072] The obtained TEM observation image was read with the image analysis software ImageJ, and after applying the median filter (Radius 2.0 pixels), a line segment was drawn from the outermost of the layer (B) in a manner including the boundary between the core (A) and the layer (B), and the brightness was formed into a curve graph along the line segment. About these operations, in more detail, it can be implemented based on the method described in the embodiments described later.

[0073] [Nucleus (A) comprising a nitrogen-containing compound]

[0074] The core (A) containing a nitrogen-containing compound is a particle or a particle group containing a nitrogen-containing compound (hereinafter, these are also collectively referred to as "core (A) particles".). The nitrogen-containing compound is not particularly limited, and examples thereof include low molecular weight amine compounds, amine adduct compounds, modified polyamine compounds, aliphatic polyamine compounds, heterocyclic polyamine compounds, alicyclic polyamine compounds, aromatic amine compounds, polyamide amine compounds, ketimine compounds, carbamate amine compounds, amide compounds, etc. These can be used alone or in combination of two or more.

[0075] Examples of the low molecular weight amine compound include, but are not limited to, compounds not having a tertiary amine such as methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diaminodiphenylmethane, diaminodiphenylsulfone, dimethylamine, diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperidine, piperidone, diphenylamine, phenylmethylamine, and phenylethylamine; compounds not having a tertiary amine such as 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1- Amino alcohols such as butoxymethyl-2-dimethylaminoethanol, methyldiethanolamine, triethanolamine, and N-β-hydroxyethylmorpholine; aminophenols such as 2-(dimethylaminomethyl)phenol and 2,4,6-tris(dimethylaminomethyl)phenol; imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2-hydroxy- imidazoles such as 1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline, 2-methylimidazoline, 2,4-dimethylimidazoline, 2-ethylimidazoline, 2-ethyl-4-methylimidazoline, 2-benzylimidazoline, 2-phenylimidazoline, 2-(o-tolyl)-imidazoline, tetramethylene-bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-imidazoline, 1,3,3-trimethyl-1,4-tetramethylene-bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1, 3,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,2-phenylene-bis-imidazoline, 1,3-phenylene-bis-imidazoline, 1,4-phenylene-bis-imidazoline, 1,4-phenylene-bis-4-methylimidazoline and other imidazolines; trimethylamine, triethylamine, benzyldimethylamine, N,N-dimethyl-ethylamine, N,N-dimethyl-butylamine, N,N-dimethyldecylamine, N,N-dimethyl-m-toluidine, N,N-dimethyl-p-toluidine, 2,6,10-trimethyl-2,6,10-triazaundecane, N,N'-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane (DABCO), 1-azabicyclo[2.2.2] octan-3-one, 1,8-diazabicyclo(5,4,0)-undecene-7, 1,5-diazabicyclo(4,3,0)-nonene-5, hexamethylenetetramine, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dipropylaminoethylamine, dibutylaminoethylamine, N-methylpiperazine, N-aminoethylpiperazine, diethylaminoethylpiperazine Tertiary aminoamines such as oxazine, 2-dimethylaminopyridine, and 4-dimethylaminopyridine; aminothiols such as 2-dimethylaminoethanethiol, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptopyridine, and 4-mercaptopyridine; aminocarboxylates such as N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, and picolinic acid; aminohydrazides such as N,N-dimethylglycine hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide, etc. These can be used alone or in combination of two or more. .

[0076] As amine adduct compounds, it is not limited to the following, and examples thereof include compounds obtained by reacting any one or more of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins with the above-mentioned low molecular amine compounds. In the present embodiment, the amine adduct compound preferably includes an imidazole amine adduct compound. The imidazole amine adduct can be a reaction product of imidazoles and any one or more of, for example, carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins. As imidazole amine adduct compounds, from the viewpoint of the formability of layer (B), it is preferred to include a reaction product of imidazoles and epoxy resins, and from the viewpoint of mechanical strength, it is particularly preferred to include a reaction product of imidazoles and bisphenol epoxy resins.

[0077] Examples of the carboxylic acid compound include, but are not limited to, succinic acid, adipic acid, sebacic acid, phthalic acid, and dimer acid.

[0078] Examples of the sulfonic acid compound include, but are not limited to, ethanesulfonic acid and p-toluenesulfonic acid.

[0079] Examples of the urea compound include, but are not limited to, urea, methyl urea, dimethyl urea, ethyl urea, and tert-butyl urea.

[0080] Examples of the isocyanate compound include, but are not limited to, aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aliphatic triisocyanates, and polyisocyanates.

[0081] Examples of the aliphatic diisocyanate include, but are not limited to, ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0082] Examples of the alicyclic diisocyanate include, but are not limited to, 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.

[0083] Examples of the aromatic diisocyanate include, but are not limited to, toluene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylene diisocyanate, and 1,5-naphthalene diisocyanate.

[0084] Examples of the aliphatic triisocyanate include, but are not limited to, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, and 1,3,6-triisocyanate methyl hexane.

[0085] As polyisocyanates, there are not limited to the following, and examples thereof include polymethylene polyphenyl polyisocyanates, polyisocyanates derived from the above-mentioned diisocyanate compounds, etc. Examples of polyisocyanates derived from the above-mentioned diisocyanate compounds include isocyanurate-type polyisocyanates, biuret-type polyisocyanates, carbamate-type polyisocyanates, allophanate-type polyisocyanates, and carbodiimide-type polyisocyanates.

[0086] The epoxy resin is not limited to the following, and examples thereof include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, tetrabromobisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenyl benzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin, diphenyl sulfone type epoxy resin, diphenyl disulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcinol type epoxy resin, methylresorcinol type epoxy resin, and catechol type epoxy resin; N,N- Trifunctional epoxy resins such as diglycidylaminobenzene epoxy resin and triazine epoxy resin; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane epoxy resin and diaminobenzene epoxy resin; multifunctional epoxy resins such as phenol novolac epoxy resin, cresol novolac epoxy resin, triphenylmethane epoxy resin, tetraphenylethane epoxy resin, dicyclopentadiene epoxy resin, naphthol aralkyl epoxy resin, brominated phenol novolac epoxy resin; monoepoxy compounds and alicyclic epoxy resins such as butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, p-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, p-xylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexanoate, and glycidyl benzoate. These can be used alone or in combination of two or more.

[0087] Examples of the amide compound include, but are not limited to, dicyandiamide and guanidine compounds as derivatives thereof, compounds obtained by adding an acid anhydride to an amine compound, and hydrazide compounds.

[0088] Examples of the hydrazide compound include, but are not limited to, succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-oxybenzoic acid hydrazide, salicylic acid hydrazide, phenylaminopropionic acid hydrazide, and maleic acid dihydrazide.

[0089] Examples of the guanidine compound include, but are not limited to, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, toluoylguanidine, etc. These may be used alone or in combination of two or more.

[0090] Among these compounds having nitrogen atoms, from the viewpoint of achieving both reactivity during thermal curing and storage stability when prepared as an epoxy resin composition, low molecular weight amine compounds, amine adduct compounds, and amide compounds are preferred, low molecular weight amine compounds and amine adduct compounds are more preferred, and compounds containing both low molecular weight amines and amine adduct compounds are particularly preferred.

[0091] As the low molecular weight amine compound, it is preferred to include an amine compound (a) having a molecular weight of 50 to 300. That is, from the viewpoint of suppressing thickening caused by the core (A) penetrating the layer (B) and reacting with the epoxy resin when the epoxy resin composition is prepared, the molecular weight is preferably 50 or more, more preferably 60 or more, and further preferably 70 or more. In addition, from the viewpoint of exhibiting high reactivity based on excellent diffusion ability, the molecular weight is preferably 300 or less, more preferably 270 or less, and further preferably 240 or less.

[0092] As the amine compound (a), from the viewpoint of excellent reactivity with the epoxy resin, imidazoles, aliphatic amine compounds, and cyclic amine compounds including tertiary amines are preferred. As the imidazole compound, imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 2-phenylimidazole are more preferred. As the aliphatic amine compound, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, Triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, piperidine; and as the cyclic amine compound containing a tertiary amine, 1,4-diazabicyclo[2.2.2]octane, 1-azabicyclo[2.2.2]octan-3-one, 1,8-diazabicyclo(5,4,0)-undecene-7, and 1,5-diazabicyclo(4,3,0)-nonene-5 are more preferred.

[0093] Regarding the content of the low molecular weight amine compound in the core (A), from the viewpoint of both the reactivity during heat curing and the stability during storage when the epoxy resin composition is prepared, in the overall mass of the core (A), preferably 0.001% by mass or more and 20% by mass or less, more preferably 0.003% by mass or more and 18% by mass or less, further preferably 0.005% by mass or more and 16% by mass or less, further preferably 0.008% by mass or more and 14% by mass or less, particularly preferably 0.01% by mass or more and 12% by mass or less. From the same viewpoint as above, the content of the amine compound (a) in the core (A) is preferably 0.001% by mass or more and 20% by mass or less, more preferably 0.003% by mass or more and 18% by mass or less, further preferably 0.005% by mass or more and 16% by mass or less, further preferably 0.008% by mass or more and 14% by mass or less, particularly preferably 0.01% by mass or more and 12% by mass or less.

[0094] From the viewpoint of mechanical strength, the amine adduct-based compound is preferably a compound obtained by reacting an epoxy resin with a low molecular weight amine compound. As the epoxy resin, from the viewpoint of toughness, bisphenol A epoxy resin and bisphenol F epoxy resin are preferred. As the low molecular weight amine compound, from the viewpoint of imparting excellent reactivity with the epoxy resin to the obtained amine adduct-based compound, among the above-mentioned low molecular weight amine compounds, imidazole compounds, compounds having at least one primary amino group and / or secondary amino group but not having a tertiary amino group, and compounds having at least one tertiary amino group and at least one active hydrogen group are more preferred.

[0095] The low molecular weight amine compound contained in the core (A) can be the unreacted low molecular weight amine compound obtained by reacting any one or more of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds and epoxy resins with the low molecular weight amine compounds to obtain an amine adduct compound.

[0096] The core (A) may contain components other than the nitrogen-containing compound, and examples thereof include, but are not limited to, phenol-based curing agents, acid anhydride-based curing agents, and catalyst-type curing agents.

[0097] The phenolic curing agent is not limited to the following, and examples thereof include phenol novolac resin, cresol novolac resin, phenol aralkyl resin, cresol aralkyl resin, naphthol aralkyl resin, biphenyl-modified phenolic resin, biphenyl-modified phenolic aralkyl resin, dicyclopentadiene-modified phenolic resin, aminotriazine-modified phenolic resin, naphthol novolac resin, naphthol-phenol co-condensation novolac resin, naphthol-cresol co-condensation novolac resin, and allyl acrylic phenolic resin.

[0098] Examples of the acid anhydride curing agent include, but are not limited to, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0099] The catalyst type curing agent is not limited to the following, and examples thereof include a cationic heat curing catalyst and a BF3-amine complex.

[0100] From the viewpoint of storage stability, the core (A) is preferably solid at 25° C. and 1013 hPa. Thus, when mixed with other components to obtain an epoxy resin composition, even if the layer (B) is scratched, the components of the core (A) are suppressed from eluting out of the layer (B), and storage stability tends to be maintained.

[0101] The particle size D at which the cumulative percentage of the core (A) under the sieve is 50% 50 It is preferably greater than 0.3 μm and less than 12 μm. 50 When the core (A) has a diameter greater than 0.3 μm, the cores can be further prevented from aggregating with each other, and the formation of the layer (B) becomes easier, and the storage stability of the epoxy resin composition tends to be further improved. 50 The diameter of the epoxy resin is 12 μm or less. When a desired epoxy resin composition is obtained, when a diluent, filler, pigment, dye, flow regulator, thickener, reinforcing agent, mold release agent, wetting agent, stabilizer, flame retardant, surfactant, organic solvent, conductive fine particles, crystalline alcohol, other resins, etc. are added, the formation of large-diameter aggregates can be prevented, and there is a tendency for the cured product to obtain sufficient long-term reliability. Regarding D of the core (A) 50 As the lower limit, it is preferably greater than 0.3 μm, more preferably 0.4 μm or more, and further preferably 0.5 μm or more. As the upper limit, it is preferably 12 μm or less, more preferably 10 μm or less, and further preferably 9 μm or less.

[0102] D of the core (A) 50 It refers to the average particle size defined by the median diameter. More specifically, it refers to the Stoke's diameter measured by a laser diffraction / light scattering method using a particle size distribution meter ("HORIBA LA-920" manufactured by Horiba, Ltd.).

[0103] As the D of the core (A) 50 The method for controlling the above numerical range is not limited to the following methods, and examples thereof include: a method of performing precise control in the crushing process of the bulk core material; performing a coarse crushing process and a fine crushing process as the crushing process of the bulk core material, and further using a precise classification device to classify the desired D 50a method of obtaining a substance with a particle size of 0.04; a method of spray-drying a solution obtained by dissolving a block core material in a solvent, etc.

[0104] As the device used for pulverization, for example, a ball mill, an attritor, a bead mill, a jet mill, etc. can be used as required, and an impact pulverization device is preferably used. Examples of the above-mentioned impact pulverization device include jet mills such as a rotary powder impact jet mill and a powder impact reverse jet mill. A jet mill is a device that uses a high-speed jet stream using air or the like as a medium to cause solid materials to impact each other and thereby micronize them. As a method for performing precise control during the pulverization process, a method for controlling the temperature, humidity, and pulverization amount per unit time during pulverization can be cited. As a method for performing precise control during the pulverization process, a method for controlling the temperature, humidity, and pulverization amount per unit time during pulverization can be cited. As a method for performing precise control after the pulverization process, a precise classifying device can be used to classify the desired D 50 The method of obtaining a substance of a certain size can be exemplified by: for example, to obtain a specified D by classification after pulverization. 50 A method of classifying a powder or granular body using a sieve (e.g., a standard sieve of 325 mesh, 250 mesh, etc.) and a classifier; a method of classifying by wind force according to the specific gravity of the particles, etc. As the classifier used, a wet classifier and a dry classifier can be listed, and a dry classifier is usually preferred. As such a classifier, for example, the "Elbow-Jet" manufactured by Nippon Iron & Steel Mining Co., Ltd., the "Fine Sharp Separator" manufactured by Hosokawa Micron Co., Ltd., the "Variable Impactor" manufactured by Sankyo Electric Co., Ltd., the "Spedic Classifier" manufactured by Saixin Enterprise Co., Ltd., the "DONASELEC" manufactured by Japan DONALDSON Co., Ltd., the "YM Microcassette" manufactured by Yaskawa Corporation, the "TurboClassifier" manufactured by Nissin Engineering Co., Ltd., various other gas separators, micron separators, MICROPLEX, ACCU-CUT and other dry classification devices can be listed, but are not limited to these.

[0105] As a method for directly granulating the particles constituting the core without crushing, there can be cited a method of spray drying a solution obtained by dissolving a blocky core material in a solvent. Specifically, there can be cited a method of uniformly dissolving the core material in an appropriate organic solvent, spraying it in the form of minute droplets in a solution state, and then drying it by hot air, etc. As a drying device at this time, there can be cited a common spray drying device.

[0106] In addition, as a method for granulating the core particles, the following method can be cited: the core material is uniformly dissolved in an appropriate organic solvent, and then a poor solvent for the nitrogen-containing compound constituting the core (A) is added while the uniform solution is vigorously stirred, thereby precipitating the core (A) in the form of fine particles. Then, after filtering and separating the precipitated particles, the solvent is dried at a low temperature below the melting point of the core (A) to remove the solvent.

[0107] D as the core (A) granulated by a method other than classification 50 The method includes, for example, by 50 Mix different particles to adjust D 50 For example, in the case of a core (A) with a large particle size that is difficult to pulverize and classify, D can be produced by adding and mixing a core (A) with a small particle size other than the core (A). 50 A curing agent within the above range.

[0108] The curing agent obtained in this way can be further classified as needed. Examples of mixers used for the purpose of mixing such powders include: a container rotating mixer that rotates the container body containing the powders to be mixed; a container fixed mixer that mixes the powders without rotating the container body but with mechanical stirring or air flow stirring; and a composite mixer that rotates the container containing the powders and uses other external forces to mix the powders.

[0109] Regarding the core (A), from the viewpoint of preventing the particles from agglomerating with each other, the particle size D at which the cumulative percentage under the sieve is 99% is used. 99 Relative to D 50 The ratio (hereinafter sometimes simply referred to as "D 99 / D 50 The particle size distribution represented by ” is preferably 8.0 or less, more preferably 7.0 or less, more preferably 6.0 or less, and particularly preferably 5.5 or less.

[0110] By making D 99 / D 50 When the ratio is 8.0 or less, the number of coarse particles in the powder particles of the core (A) is small, and the formation of aggregates tends to be suppressed, thereby suppressing the deterioration of the physical properties of the cured product obtained by curing the epoxy resin composition when the epoxy resin composition is prepared.

[0111] D 99 / D 50 The smaller the value of means, the sharper the particle size distribution of the core (A), and when the epoxy resin composition is prepared, a homogeneous cured product is easily obtained, and good curing performance tends to be obtained.

[0112] D 99 / D 50It is preferably 1.0 or more. 99 / D 50 When the value is 1.0 or more, there is a tendency to suppress the formation of many gaps between the core (A) particles. 99 / D 50 It is more preferably 1.2 or more, more preferably 1.5 or more, more preferably 1.7 or more, and particularly preferably 2.0 or more.

[0113] The particle size D at which the cumulative percentage under the sieve is 99% 99 It refers to the average particle size defined by the median diameter. More specifically, it refers to the Stoke's diameter measured by a laser diffraction / light scattering method using a particle size distribution meter ("HORIBA LA-920" manufactured by Horiba, Ltd.).

[0114] As the D of the core (A) 99 / D 50 The method of controlling the above-mentioned numerical range can be listed as follows: 50 The conditions of the method are adjusted to achieve the desired D 99 / D 50 method.

[0115] In one embodiment, the specific surface area value Y (m 2 / g) multiplied by the particle size D at which the cumulative percentage under the sieve is 50% 50 The value obtained by measuring the relative humidity (μm) may be 3.0 or more and 9.0 or less.

[0116] When the value is 3.0 or more, aggregation of the core (A) particles tends to be suppressed, and when the value is 9.0 or less, formation of the layer (B) tends to be facilitated.

[0117] From the viewpoint of suppressing aggregation of the core (A) particles, the above value may be 3.5 or more, or 4.0 or more. From the viewpoint of facilitating the formation of the layer (B), the above value may be 8.6 or less, or 8.3 or less.

[0118] The specific surface area value Y(m 2 / g) can be measured according to the method described in the Examples.

[0119] In one embodiment, the specific surface area value Y (m 2 / g) multiplied by the particle size D 50 The value obtained by (μm) can be more than 9.0 and less than 18.0. When the above value exceeds 9.0, there is a tendency to improve the reactivity, and when the above value is less than 18.0, there is a tendency to form a layer (B) with sufficient stability. From this viewpoint, the above value can be set to less than 17.0, and can be set to less than 16.5.

[0120] The specific surface area value Y (m 2 / g) multiplied by the particle size D 50 The method of obtaining the value of (μm) includes, for example, adjusting the control D 50 The method of modifying the surface of the core (A) by adjusting the conditions of the method. Examples of methods for modifying the surface include mechanically rounding the particles and hot air treatment. In such cases, the above value tends to decrease. On the other hand, the above value can be increased by appropriately setting the above pulverizing device, pulverizing conditions, classifying device, and classification conditions.

[0121] [Layer (B)]

[0122] The layer (B) is not particularly limited as long as it has desired dyeability, and examples thereof include layers containing synthetic resins and inorganic oxides. Among these, synthetic resins are preferred from the viewpoint of stability during storage and ease of destruction during heating.

[0123] The synthetic resin used in layer (B) is not limited to the following, and examples thereof include epoxy resins, phenolic resins, polyester resins, polyethylene resins, nylon resins, polystyrene resins, and urethane resins. Among these, epoxy resins, phenolic resins, and urethane resins are preferred from the viewpoint of balancing the stability of layer (B) and the destructiveness during heating.

[0124] The epoxy resin used in layer (B) is not limited to the following, and examples thereof include epoxy resins having two or more epoxy groups, resins produced by reaction of epoxy resins having two or more epoxy groups with compounds having two or more active hydrogens, reaction products of compounds having two or more epoxy groups with compounds having one active hydrogen and a carbon-carbon double bond, etc. Among these, from the viewpoint of stability, resins produced by reaction of compounds having two or more epoxy groups with compounds having two or more active hydrogens are preferred, and in particular, reaction products of amine-based curing agents with epoxy resins having two or more epoxy groups are more preferred. Examples of epoxy resins include the above-mentioned epoxy resins, and examples of amine-based curing agents include nitrogen-containing compounds used in core (A).

[0125] Examples of the phenolic resin include, but are not limited to, phenol-formaldehyde polycondensates, cresol-formaldehyde polycondensates, resorcinol-formaldehyde polycondensates, bisphenol A-formaldehyde polycondensates, and polyethylene polyamine-modified products of phenol-formaldehyde polycondensates.

[0126] Examples of the polyester resin include, but are not limited to, ethylene glycol-terephthalic acid-polypropylene glycol polycondensates, ethylene glycol-butylene glycol-terephthalic acid polycondensates, and terephthalic acid-ethylene glycol-polyethylene glycol polycondensates.

[0127] Examples of the polyethylene resin include, but are not limited to, ethylene-propylene-vinyl alcohol copolymers, ethylene-vinyl acetate copolymers, and ethylene-vinyl acetate-acrylic acid copolymers.

[0128] Examples of the nylon-based resin include, but are not limited to, adipic acid-hexamethylenediamine polycondensates, sebacic acid-hexamethylenediamine polycondensates, and p-phenylenediamine-terephthalic acid polycondensates.

[0129] Examples of the polystyrene-based resin include, but are not limited to, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, acrylonitrile-styrene-divinylbenzene copolymers, and styrene-acryl alcohol copolymers.

[0130] The urethane resin is not limited to the following, and examples thereof include isocyanate monomers such as butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolidine diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate, or condensates thereof, or condensates of polymers thereof with monohydric alcohols or polyhydric alcohols, etc. Among these, urethane resins that are addition polymers of monohydric alcohols or polyhydric alcohols with monoisocyanates or polyisocyanates are preferred.

[0131] Examples of the inorganic oxide include, but are not limited to, boron compounds such as boron oxide and boric acid esters, silicon dioxide, calcium oxide, etc. Among these, boron oxide is preferred from the viewpoint of stability of the film constituting the shell and ease of destruction during heating.

[0132] From the viewpoint of the balance between storage stability and curability when producing the epoxy resin composition of this embodiment, layer (B) preferably contains reaction products of two or more selected from the group consisting of isocyanate compounds, active hydrogen compounds, nitrogen-containing compounds, and epoxy resins.

[0133] As the isocyanate compound, the nitrogen-containing compound and the epoxy resin, the compounds described above with respect to the core (A) can be used.

[0134] Examples of the active hydrogen compound include, but are not limited to, water, a compound having at least one primary and / or secondary amino group, a compound having at least one hydroxyl group, etc. These active hydrogen compounds may be used alone or in combination of two or more.

[0135] Examples of the compound having at least one primary amino group and / or secondary amino group include, but are not limited to, aliphatic amines, alicyclic amines, and aromatic amines.

[0136] The aliphatic amines are not limited to the following, and examples thereof include alkylamines such as methylamine, ethylamine, propylamine, butylamine, and dibutylamine; alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, and hexamethylenediamine; polyalkylenepolyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; and polyoxyalkylenepolyamines such as polyoxypropylenediamine and polyoxyethylenediamine.

[0137] Examples of the alicyclic amine include, but are not limited to, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, and isophoronediamine.

[0138] Examples of the aromatic amine include, but are not limited to, aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

[0139] Examples of the compound having at least one hydroxyl group include alcohol compounds and phenol compounds.

[0140] The alcohol compound is not limited to the following substances, and examples thereof include monohydric alcohols such as methanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, stearyl alcohol, eicosanol, allyl alcohol, crotyl alcohol, propargyl alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; polyhydric alcohols such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, hydrogenated bisphenol A, neopentyl glycol, glycerol, trimethylolpropane, and pentaerythritol; polyhydric alcohols such as compounds having two or more secondary hydroxyl groups in one molecule obtained by reacting a compound having at least one epoxy group with a compound having at least one hydroxyl group, carboxyl group, primary amino group, secondary amino group, or thiol group; and the like.

[0141] These alcohol compounds may be primary alcohols, secondary alcohols, or tertiary alcohols.

[0142] Examples of phenolic compounds include, but are not limited to, monophenols such as phenol, cresol, xylenol, carvacrol, thymol, and naphthol; and polyphenols such as catechol, resorcinol, hydroquinone, bisphenol A, bisphenol F, pyrogallol, phloroglucinol, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol.

[0143] As these compounds having at least one hydroxyl group, polyols and polyphenols are preferred from the viewpoint of potential and solvent resistance, and polyols are more preferred.

[0144] The reaction conditions for preparing the reaction product of two or more selected from the group consisting of isocyanate compounds, active hydrogen compounds, nitrogen-containing compounds and epoxy resins contained in the layer (B) are not particularly limited, but are generally in the range of -10°C to 150°C and for a reaction time of 10 minutes to 12 hours.

[0145] When the isocyanate compound and the active hydrogen compound are used to prepare the reaction product included in the layer (B), the mixing ratio is preferably in the range of 1:0.1 to 1:1000 in terms of (isocyanate group in the isocyanate compound):(active hydrogen in the active hydrogen compound) (equivalent ratio).

[0146] The above reaction can be carried out in a predetermined dispersion medium as required.

[0147] Examples of the dispersion medium include solvents, plasticizers, and resins.

[0148] Examples of the solvent include, but are not limited to, hydrocarbons such as benzene, toluene, xylene, cyclohexane, mineral spirits, and naphtha; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ethyl ether acetate; alcohols such as methanol, isopropanol, n-butanol, butyl cellosolve, and butyl carbitol; and water.

[0149] Examples of plasticizers include, but are not limited to, phthalic acid diester plasticizers such as dibutyl phthalate and di(2-ethylhexyl) phthalate; aliphatic dibasic acid ester plasticizers such as di(2-ethylhexyl) adipate; phosphate triester plasticizers such as tricresyl phosphate; and glycol ester plasticizers such as polyethylene glycol esters.

[0150] Examples of the resins include, but are not limited to, silicone resins, epoxy resins, and phenolic resins.

[0151] These can be used alone or in combination of two or more.

[0152] In the above, the reaction of the epoxy resin and the nitrogen-containing compound is usually carried out at a temperature range of -10°C to 150°C, preferably 0°C to 100°C, for a reaction time of 1 hour to 168 hours, preferably 2 hours to 72 hours. In addition, the dispersion medium is preferably a solvent or a plasticizer.

[0153] The reaction product, as a mass % in layer (B), is usually 1 mass % or more, preferably 50 mass % or more, and may be 100 mass %.

[0154] As a method for forming the layer (B), for example, the following methods (1) to (3) may be mentioned.

[0155] (1): After dissolving / dispersing the core (A) particles and the material for forming the layer (B) (layer (B) forming material) in a solvent serving as a dispersion medium, the solubility of the layer (B) forming material in the dispersion medium is reduced to precipitate the layer (B) forming material on the surface of the core (A) particles.

[0156] (2): A method in which the core (A) particles are dispersed in a dispersion medium, and the layer (B) forming material is added to the dispersion medium to be precipitated on the core (A) particles.

[0157] (3): A method in which a layer (B) forming material is added to a dispersion medium, and the surface of the core (A) particles is used as a reaction field to form the layer (B) there.

[0158] Here, the above methods (2) and (3) are preferred because they can carry out reaction and covering at the same time.

[0159] It should be noted that the dispersion medium in the above methods (1) to (3) includes solvents, plasticizers, resins, etc. In addition, the solvents, plasticizers, and resins may be the same as those used in the reaction for preparing the reaction product of two or more selected from the group consisting of isocyanate compounds, active hydrogen compounds, nitrogen-containing compounds, and epoxy resins contained in the above layer (B).

[0160] The method for separating the epoxy resin curing agent from the dispersion medium after forming the layer (B) by the above methods (2) and (3) is not particularly limited, and an example thereof is a method of removing the dispersion medium and unreacted raw materials for forming the layer (B) by filtration.

[0161] After removing the dispersion medium, the epoxy resin curing agent is preferably washed.

[0162] The washing method is not particularly limited, and the residue may be washed with a solvent that does not dissolve the residue during separation by filtration.

[0163] By filtering, washing and drying, the epoxy resin curing agent can be obtained in a powdered form. The drying method is not particularly limited, and is preferably dried at a temperature below the melting point or softening point of the core (A) and the layer (B), and examples thereof include reduced pressure drying. By being made into a powdered state, the epoxy resin curing agent and the epoxy resin can be easily blended. In addition, when an epoxy resin is used as a dispersion medium, an epoxy resin composition that is integrated with the epoxy resin while forming the layer (B) can be obtained, and therefore it is suitable.

[0164] The formation reaction of layer (B) is carried out in a temperature range of -10°C to 150°C, preferably 0°C to 100°C, with a reaction time of 10 minutes to 72 hours, preferably 30 minutes to 24 hours. After the formation reaction of layer (B) is completed, the epoxy resin curing agent is preferably allowed to stand in an environment below 5 to 12°C for more than 8 hours (after a standing step). In the case of the standing step, there is a tendency for layer (B) to have the desired dyeing properties. It should be noted that in the standing step in the present embodiment, the temperature difference between the measured temperature and the set temperature is preferably low. For example, the lowest temperature T from the start time t1 to the end time t2 of the standing step is preferably L With the maximum temperature T H The difference is 4° C. or less. In this case, it is easier to obtain a layer (B) having desired dyeing properties.

[0165] It should be noted that, as mentioned above, the formation reaction can be implemented using a dispersion medium, and the operation of removing the dispersion medium can be performed between the formation reaction and the standing process. In addition, the set temperature in the standing process can be lower than the temperature condition of the formation reaction. As an example, as the set temperature in the standing process, it can be set to more than 40 ° C lower than the reaction temperature in the formation reaction, and can be set to more than 45 ° C lower. Then, the formation reaction and the standing process can be implemented in the same system, and can also be implemented in different systems.

[0166] The presence of the layer (B) can be confirmed by TEM observation described later.

[0167] The thickness of layer (B) is preferably 1 nm to 1000 nm, more preferably 2 nm to 800 nm, further preferably 3 nm to 600 nm, and further preferably 4 nm to 400 nm. When the thickness of layer (B) is 1 nm or more, sufficient stability tends to be imparted. In addition, when layer (B) is 1000 nm or less, sufficient reactivity tends to be imparted.

[0168] Here, the thickness of layer (B) refers to the distance between an arbitrary point on the boundary of brightness γ corresponding to the boundary between layer (B) and core (A) and the point where a line segment connecting the point to a point of brightness β corresponding to the outermost portion of layer (B) is the shortest. In addition, the thickness of layer (B) may vary depending on the position, and in this case, the thickness range is preferably in the range of 1 nm to 1000 nm, more preferably in the range of 2 nm to 800 nm, more preferably in the range of 3 nm to 600 nm, and more preferably in the range of 4 nm to 400 nm.

[0169] [Colorability of layer (B)]

[0170] For the epoxy resin curing agent of this embodiment, when TEM observation is performed after staining with ruthenium tetroxide and osmium tetroxide and a brightness curve diagram is obtained by image processing, the inside of the above-mentioned layer (B) contains a region with brightness α, and the above-mentioned brightness α is higher than the brightness β of the outermost part of the above-mentioned layer (B) and the brightness γ of the boundary between the above-mentioned layer (B) and the above-mentioned core (A). The presence of the above-mentioned region inside the layer (B) can be confirmed based on the method described in the examples described later.

[0171] When the epoxy resin curing agent is a masterbatch epoxy resin curing agent composition described below, the epoxy resin and curing agent components may be separated by a centrifugal separator after adding a dispersion medium as needed, and then the curing agent components may be collected and dried to obtain a single epoxy resin curing agent.

[0172] Examples of the dispersion medium include solvents, plasticizers, and resins, and the dispersion medium can be selected from commercially available dispersion media depending on the solubility of the layer (B).

[0173] In this specification, when there is a layer with different dyeing properties between the region of the epoxy resin composition for dyeing and the core (A) in the above-mentioned TEM observation, it is referred to as layer (B). The difference in dyeing properties can be confirmed by visually observing the TEM image. In addition, the difference in dyeing properties can be confirmed by the brightness of the region of the epoxy resin composition for dyeing to the core (A) in the above-mentioned brightness curve diagram is not monotonous.

[0174] The layer (B) may be a single layer or a multi-layer layer.

[0175] In this specification, the outermost portion of layer (B) is defined as the position with the lowest brightness near the boundary between layer (B) and the dyeing epoxy resin composition region, and the boundary between core (A) and layer (B) is defined as the position with the lowest brightness near the boundary between core (A) and layer (B). When layer (B) is a multilayer, it is sufficient that at least one layer (B) has the desired dyeability, and preferably all layers (B) have the desired dyeability.

[0176] The circularity of the epoxy resin curing agent of this embodiment may be 0.90 or more, 0.93 or more, 0.95 or more, or 0.98 or more. The circularity indicates the degree of proximity to a sphere, and the circularity of a sphere is 1. In addition, the surface of the epoxy resin curing agent (the surface of layer (B)) may be smooth, or unevenness may be observed. When the surface of layer (B) is smooth, the result of TEM image analysis is that an image that appears to be linear or curved can be observed at the boundary between layer (B) and the epoxy resin composition region for dyeing (see the following). Figure 1 , 3On the other hand, when the surface of the layer (B) is observed to be uneven, the result of TEM image analysis is that the boundary between the layer (B) and the epoxy resin composition region for dyeing is observed to be wavy or wrinkled (see the following). Figure 5 ).

[0177] In addition, this embodiment may also include: Figure 2 In the case where the brightness of the highest position in the layer (B) shown is higher than the maximum brightness of the core (A), Figure 4 The case where the brightness of the position with the highest brightness in the layer (B) is lower than the maximum brightness of the core (A) is shown. In any embodiment, as long as the brightness α higher than the brightness β and the brightness γ is observed, it can be preferably used.

[0178] The present inventors have conducted intensive research and found that, by subjecting the epoxy resin curing agent to the above-mentioned standing step after the formation reaction of layer (B) is completed, it is possible to obtain the epoxy resin curing agent of the present embodiment (hereinafter also referred to as low-dyeability epoxy resin curing agent) having an area inside layer (B) in which the dyeability using ruthenium tetroxide and osmium tetroxide based on the above-mentioned dyeing method is significantly reduced.

[0179] Compared with an epoxy resin curing agent having a covering layer that can be easily dyed throughout by ruthenium tetroxide or osmium tetroxide (hereinafter also referred to as a high-dyeability epoxy resin curing agent), the low-dyeability epoxy resin curing agent maintains reactivity and has improved tolerance to low-molecular epoxy resin compounds, solvents, and low-molecular acrylic resins, and can also provide excellent storage stability when applied to epoxy resin compositions containing these.

[0180] In addition, when an epoxy resin composition containing a filler is prepared using a low-dyeing epoxy resin curing agent and cured, the appearance of the cured product in a micro region is observed. The result shows that the filler is more uniformly dispersed than that obtained with a high-dyeing epoxy resin curing agent, and the cured product has an excellent appearance.

[0181] Although not intended to be limiting, the mechanism by which the low-dyeability epoxy resin curing agent of the present embodiment improves resistance to low-molecular epoxy compounds, solvents, and low-molecular acrylic compounds is presumed as follows.

[0182] The layer (B) of the low-dyeing epoxy resin has a high crosslinking density, so it is difficult for ruthenium tetroxide and osmium tetroxide to penetrate into the layer during dyeing, so it shows low dyeing. That is, by making the crosslinking points and molecular chains exist in a high-density state, the low-molecular epoxy compounds, solvents, and low-molecular acrylic compounds are inhibited from penetrating into the layer (B), and these low-molecular compounds are prevented from dissolving the core (A), thereby showing excellent storage stability. On the other hand, during the reaction, the influence of the strength improvement in the high temperature range is very small, so the reactivity is maintained.

[0183] Although not intended to be limiting, the mechanism by which the epoxy resin composition containing fillers is prepared using the low-dyeing epoxy resin curing agent of this embodiment and the fillers are more uniformly dispersed when the appearance of the cured product in a micro region is observed after curing to obtain a cured product with excellent appearance is speculated as follows.

[0184] In the layer (B) of the low-dyeing epoxy resin curing agent, crosslinking points and molecular chains exist at high density, so the surface hardness is high. As a result, the contact area when colliding with the filler during compounding is small, so the probability of curing agent aggregation and filler aggregation is reduced, and the uniform dispersion state of the filler can be maintained until the stage after curing.

[0185] As described above, when evaluating the dyeability of the epoxy resin curing agent of the present embodiment, a dyed cured product is obtained. That is, the method for manufacturing the dyed cured product of the present embodiment includes the following steps: a step (S1) of electronically dyeing the epoxy resin curing agent having a core (A) and a layer (B) covering the core (A) with ruthenium tetroxide; a step (S2) of obtaining a cured product of a composition containing the epoxy resin curing agent that has undergone the step (S1); and a step (S3) of electronically dyeing a slice of the cured product with osmium tetroxide. The epoxy resin curing agent of step (S1) corresponds to the epoxy resin curing agent of the present embodiment. Steps (S2) and (S3) can be implemented in the same manner as the method for evaluating the dyeability of the layer (B) described above. By subjecting the dyed cured product to the above-mentioned TEM observation and image processing, it can be typically confirmed that the interior of the layer (B) has a region with a brightness higher than the brightness of the outermost portion and the brightness of the above-mentioned boundary.

[0186] 〔Epoxy resin composition〕

[0187] The epoxy resin curing agent of the present embodiment can be made into an epoxy resin composition containing epoxy resin (C). The above epoxy resin composition can also be used in the form of a masterbatch type epoxy resin curing agent composition. That is, the masterbatch type epoxy resin curing agent composition containing the epoxy resin curing agent of the present embodiment is also included in the present embodiment.

[0188] 〔Epoxy resin (C)〕

[0189] As the epoxy resin (C), the above-mentioned epoxy resins can be used. The epoxy resin (C) can be used alone or in combination of two or more.

[0190] Regarding the mass ratio of the epoxy resin curing agent to the epoxy resin (C) in this embodiment (epoxy resin curing agent: epoxy resin), from the viewpoint of imparting sufficient reactivity and inhibiting aggregation of the epoxy resin curing agents and imparting sufficient mechanical strength to the cured product, it is preferably 0.1:100 to 1000:100, more preferably 0.5:100 to 500:100, and particularly preferably 1:100 to 200:100. In addition, when the above-mentioned epoxy resin composition is used in the form of a masterbatch type curing agent, from the viewpoint of imparting sufficient reactivity as a curing agent and inhibiting aggregation of the curing agents, the mass ratio of the epoxy resin curing agent to the epoxy resin (C) (epoxy resin curing agent: epoxy resin) of the present embodiment is preferably 0.1:100 to 1000:100, more preferably 1:100 to 500:100, further preferably 5:100 to 300:100, further preferably 10:100 to 200:100, and particularly preferably 20:100 to 150:100.

[0191] The epoxy resin (C) in the epoxy resin composition of the present embodiment preferably contains a bisphenol epoxy resin from the viewpoint of handling properties and heat resistance, and more preferably contains any one or more of a bisphenol A epoxy resin and a bisphenol F epoxy resin from the viewpoint of imparting sufficient mechanical properties.

[0192] The total chlorine content in the epoxy resin (C) is preferably 2500 ppm or less, more preferably 2000 ppm or less, further preferably 1500 ppm or less, and particularly preferably 900 ppm or less, from the viewpoint of obtaining an epoxy resin composition having excellent electrical properties and an excellent balance between curability and storage stability.

[0193] From the viewpoint of achieving a predetermined technical significance, the total chlorine content in the epoxy resin (A) is preferably 0.01 ppm or more, more preferably 0.05 ppm or more, further preferably 0.1 ppm or more, and particularly preferably 0.5 ppm or more.

[0194] Here, the total amount of chlorine contained in the epoxy resin (C) indicates the total amount of organic chlorine and inorganic chlorine contained in the epoxy resin (C), and is a mass reference value relative to the epoxy resin (C).

[0195] The total chlorine content of the epoxy resin (C) can be measured by the following method.

[0196] The epoxy resin (C) is washed with xylene, and the washing and filtering are repeated until there is no epoxy resin in the xylene as the washing liquid. Then, the filtrate is distilled under reduced pressure at below 100°C to obtain an epoxy resin. 1 to 10 g of the obtained epoxy resin sample is accurately weighed so that the titration amount is 3 to 7 mL, dissolved in 25 mL of ethylene glycol monobutyl ether, 25 mL of 1 equivalent KOH propylene glycol solution is added thereto, and after boiling for 20 minutes, titration is performed with a silver nitrate aqueous solution, and calculation can be performed based on the titration amount.

[0197] Here, among all the chlorine, the chlorine contained in the 1,2-chloroethanol group is generally referred to as hydrolyzable chlorine. The amount of hydrolyzable chlorine in the epoxy resin (C) is preferably 100 ppm or less, more preferably 50 ppm or less, further preferably 0.01 ppm or more and 20 ppm or less, and further preferably 0.05 ppm or more and 10 ppm or less. If the amount of hydrolyzable chlorine in the epoxy resin (C) is 100 ppm or less, it is advantageous from the viewpoint of making the epoxy resin composition of the present embodiment have both high curability and storage stability, and there is a tendency that the cured product of the epoxy resin composition of the present embodiment shows excellent electrical properties.

[0198] Here, the hydrolyzable chlorine in the epoxy resin (C) can be measured by the following method.

[0199] 3 g of a sample is dissolved in 50 mL of toluene, 20 mL of a 0.1 N KOH methanol solution is added thereto, and the mixture is boiled for 15 minutes and then titrated with an aqueous silver nitrate solution. The amount of titration can be used for calculation.

[0200] [Alcohol compound (D) represented by formula (1)]

[0201] The epoxy resin composition of the present embodiment may further contain an alcohol compound (D) represented by the following formula (1) (hereinafter also referred to as “component (D)”).

[0202] By containing the component (D), the epoxy resin composition of the present embodiment tends to maintain storage stability and improve low-temperature curability.

[0203]

[0204] In formula (1), X1 represents an alkylene group having 2 or more and 5 or less carbon atoms which optionally has a substituent R, and the substituents R and R1 to R5 each independently represent a hydrogen atom, an alkyl group, an unsaturated aliphatic group, an aromatic group, a substituent containing a heteroatom, or a halogen atom, and here, any one of R1 to R5 is optionally selected to form a condensed ring compound of the same ring. As the substituent containing a heteroatom, for example, it can be a substituent containing a halogen atom.

[0205] Examples of the alcohol compound represented by the formula (1) include, but are not limited to, 3-phenoxy-1-propanol, 3-phenoxy-1,2-propanediol, 3-phenoxy-1,3-propanediol, 3-(o-tolyloxy)-1,2-propanediol, 3-(2-methoxyphenoxy)propane-1,2-diol, bisphenol A (3-hydroxypropyl) glycidyl ether, and bisphenol A (2,3-dihydroxypropyl) glycidyl ether, and bisphenol A (2,3-dihydroxypropyl) glycidyl ether is particularly preferred. These can be used alone or in combination of two or more.

[0206] Regarding the addition amount of component (D), from the viewpoint of giving full play to the effect of reactivity improvement when added to the epoxy resin composition of the present embodiment, it is preferably 0.0001% by mass or more relative to the epoxy resin composition as a whole, more preferably 0.001% by mass or more, further preferably 0.005% by mass or more, and particularly preferably 0.01% by mass or more. In addition, from the viewpoint of suppressing the degradation of storage stability caused by excessive addition, it is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2.5% by mass or less, and further more preferably 2% by mass or less.

[0207] Component (D) may be added when mixing with other components, may be generated in the system after mixing, or may be generated in the system when manufacturing the core (A), layer (B) and epoxy resin (C).

[0208] 〔Other additives〕

[0209] The epoxy resin composition of the present embodiment may further include, in addition to the above-mentioned components, epoxy resin curing agents other than the epoxy resin curing agent of the present embodiment, low molecular weight epoxy compounds, solvents, low molecular weight acrylic compounds, organic fillers, inorganic fillers, pigments, dyes, flow regulators, thickeners, release agents, wetting agents, flame retardants, surfactants, resins other than epoxy resins, etc.

[0210] As epoxy resin curing agents other than the epoxy resin curing agent of the present embodiment, in addition to the nitrogen-containing compounds, phenolic curing agents, acid anhydride curing agents, and catalyst-type curing agents that can be listed as components of the above-mentioned core (A), active ester curing agents, cyanate curing agents, thiol curing agents, etc. can also be listed.

[0211] The active ester-based curing agent is a curing agent that functions as a curing agent for epoxy resin and has an active ester in the molecule.

[0212] When the epoxy resin composition of the present embodiment contains an active ester-based curing agent, hydroxyl groups that are a factor inducing a high dielectric loss tangent are not generated in the epoxy resin composition due to the reaction between the active ester and the epoxy group, and thus the dielectric loss tangent tends to be reduced.

[0213] As active ester curing agent, there is no particular restriction, from the viewpoint of ensuring crosslinking density, preferably a compound having more than 2 active ester groups in 1 molecule. In addition, from the viewpoints of heat resistance of the epoxy resin composition of the present embodiment, it is more preferred to obtain an active ester compound obtained by reacting a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound, and further preferably an active ester compound obtained by reacting a carboxylic acid compound with one or more of phenol compounds, naphthol compounds, and thiol compounds. And, it is further preferred to obtain an aromatic compound having more than 2 active ester groups in 1 molecule by reacting a carboxylic acid compound with an aromatic compound having a phenolic hydroxyl group. And, it is further preferred to be the following aromatic compound: an aromatic compound obtained by reacting a compound having at least 2 or more carboxylic acids in 1 molecule with an aromatic compound having a phenolic hydroxyl group, and an aromatic compound having more than 2 active ester groups in 1 molecule of the aromatic compound.

[0214] In addition, the active ester curing agent can be linear or multi-branched. In addition, compounds having at least two carboxylic acids in one molecule tend to improve compatibility with epoxy resins as long as they contain aliphatic chains, and improve heat resistance as long as they have aromatic rings.

[0215] Here, examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. In particular, from the viewpoint of heat resistance of the epoxy resin composition of the present embodiment, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, and terephthalic acid are preferred, and isophthalic acid and terephthalic acid are more preferred.

[0216] Examples of the thiocarboxylic acid compound include thioacetic acid and thiobenzoic acid, but the thiocarboxylic acid compound is not particularly limited thereto.

[0217] The phenol compound or naphthol compound mentioned above is not limited to the following, and examples thereof include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzyl alcohol, dicyclopentadienyl diphenol, and phenol novolac. Among these, from the viewpoint of heat resistance of the epoxy resin composition of the present embodiment and solubility in epoxy resin and solvent, bisphenol A, bisphenol F, bisphenol S, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzyl alcohol, dicyclopentadienyl diphenol, phenol novolac are preferred, and catechol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzyl alcohol, dicyclopentadienyl diphenol, phenol novolac are more preferred. Tetrahydroxybenzophenone, phloroglucinol, benzyl alcohol, dicyclopentadienyl diphenol, phenol novolac, further preferably 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyl diphenol, phenol novolac, further more preferably dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyl diphenol, phenol novolac, further preferably dicyclopentadienyl diphenol, phenol novolac, particularly preferably dicyclopentadienyl diphenol (Dicyclopentadienyldiphenol).

[0218] Examples of the thiol compound include benzenedithiol and triazine dimethiol, but are not particularly limited thereto.

[0219] As for the active ester compound as the active ester curing agent, the active ester compound disclosed in Japanese Patent Publication No. 2004-277460 and Japanese Patent Publication No. 2013-40270 can be used, and commercially available active ester compounds can also be used. As commercially available active ester compounds, for example, trade names made by DIC: EXB9451, EXB9460, EXB9460S, HPC-8000-65T (active ester compound containing dicyclopentadiene type diphenol structure), EXB9416-70BK (active ester compound containing naphthalene structure), EXB9050L-62M (active ester compound containing phosphorus atom), trade names made by Mitsubishi Chemical: DC808 (active ester compound containing acetylated product of phenol novolac), YLH1026 (active ester compound containing benzoylated product of phenol novolac), etc. can be used 1 kind or in combination of 2 or more kinds.

[0220] Cyanate-based curing agent refers to a material that works as a curing agent for epoxy resin and has a cyanate group in the molecule. The epoxy resin composition of the present embodiment is by comprising a cyanate-based curing agent as other additives, thereby generating oxazoline rings, oxazolinone rings by the reaction with epoxy group and giving flexibility to the epoxy resin composition, and forming a triazine skeleton by the trimerization of cyanate-based, therefore having the tendency to reduce warping and make heat resistance particularly good. In addition, hydroxyl is not easily generated during reaction, therefore having the tendency that dielectric loss tangent can be suppressed to be lower.

[0221] Examples of cyanate curing agents include, but are not limited to, novolac type (phenol novolac type, alkylphenol novolac type, etc.) cyanate resins, dicyclopentadiene type cyanate resins, bisphenol type (bisphenol A type, bisphenol F type, bisphenol S type, etc.) cyanate resins, and prepolymers of these that are partially triazine-treated. Specific examples of the cyanate resin include, for example, difunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylene))benzene, bis(4-cyanatephenyl)sulfide, and bis(4-cyanatephenyl)ether; polyfunctional cyanate resins derived from phenol novolac, cresol novolac, and a phenol resin containing a dicyclopentadiene structure; and prepolymers obtained by partially triazinizing these cyanate resins. These may be used alone or in combination of two or more.

[0222] As the thiol-based curing agent, any curing agent having two or more thiol groups in one molecule is acceptable, and is not limited to the following, and examples thereof include 3,3'-dithiodipropionic acid, trimethylolpropane tris(thioglycolate), pentaerythritol tetra(thioglycolate), ethylene glycol dithioglycolate, 1,4-bis(3-mercaptobutyryloxy)butane, tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, 1,3,5-tris(3- Mercaptobutoxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexa(3-mercaptopropionate), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 4-butanedithiol, 1,6-hexanedithiol, 1,10-decanedithiol, etc. From the viewpoint of impact resistance, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutoxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritoltetrakis(3-mercaptopropionate), and pentaerythritoltetrakis(3-mercaptobutyrate) are preferred, and from the viewpoint of low-temperature curability, pentaerythritoltetrakis(3-mercaptopropionate) and pentaerythritoltetrakis(3-mercaptobutyrate) are more preferred. These can be used alone or in combination of two or more.

[0223] In the present specification, the low molecular weight epoxy compound is defined as a compound other than the compounds exemplified in the epoxy resin (C) and having a viscosity of 1 mPa·s or more and less than 3 Pa·s at 25° C. The low molecular weight epoxy compound is sometimes also referred to as a reactive diluent.

[0224] The low molecular weight epoxy compound is not limited to the following, and examples thereof include the following epoxy compounds having no aromatic ring and epoxy compounds having an aromatic ring.

[0225] Examples of the monofunctional epoxy compound having no aromatic ring include compounds such as n-butyl glycidyl ether, tert-butyl glycidyl ether, allyl glycidyl ether, and 2-ethylhexyl glycidyl ether.

[0226] Examples of the monofunctional epoxy compound having one or more aromatic rings include styrene oxide, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, and compounds such as SY-OPG (trade name) manufactured by Sakamoto Yakuin Kogyo Co., Ltd.

[0227] Examples of the difunctional epoxy compound having no aromatic ring include 1,4-cyclohexanedimethanol diglycidyl ether, 1,3-cyclohexanedimethanol diglycidyl ether, (3,4-epoxycyclohexyl)methyl-3,4-epoxycyclohexylcarboxylate, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, dicyclopentadienyl dimethanol diglycidyl ether, vinyl cyclohexene dioxide, YX-8000 manufactured by Mitsubishi Chemical Corporation, and SR-8EGS manufactured by Sakamoto Yakuin Kogyo Co., Ltd.

[0228] Examples of the bifunctional epoxy compound having one or more aromatic rings include compounds such as hexahydrophthalic acid diglycidyl ether, resorcinol diglycidyl ether, tert-butylhydroquinone diglycidyl ether, diglycidyl ether of polyoxyalkylene bisphenol A, N,N-diglycidyl aniline, and N,N-diglycidyl o-toluidine.

[0229] Examples of the trifunctional epoxy compound include trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, and N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropyloxy)aniline.

[0230] Examples of the solvent include, but are not limited to, hydrocarbons such as toluene, xylene, cyclohexane, mineral spirits, and solvent naphtha; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ethyl ether acetate; alcohols such as isopropyl alcohol, n-butanol, butyl cellosolve, butyl carbitol, and 1-methoxy-2-propanol; and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0231] The low molecular weight acrylic compound refers to an acrylic compound having a molecular weight of 700 or less, and is not limited to the following, and examples thereof include compounds having (meth)acryloyl groups at both ends of polyalkylene oxide, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, trimethylolpropane type multifunctional (meth)acrylate, pentaerythritol type multifunctional (meth)acrylate, dipentaerythritol type multifunctional (meth)acrylate, epoxy (meth)acrylate, and the like.

[0232] The organic filler functions as an impact relaxant capable of relaxing stress caused by impact.

[0233] The epoxy resin composition of the present embodiment can further improve the adhesiveness with various connection members by containing an organic filler, and also tends to suppress the occurrence and intensification of fillet cracks.

[0234] Examples of organic fillers include, but are not limited to, acrylic resins, silicone resins, butadiene rubber, polyester, polyurethane, polyvinyl butyral, polyarylate, polymethyl methacrylate, acrylic rubber, polystyrene, NBR, SBR, silicone-modified resins, and organic microparticles containing copolymers thereof as components.

[0235] From the viewpoint of improving adhesion, examples of organic fine particles include alkyl (meth)acrylate-butadiene-styrene copolymers, alkyl (meth)acrylate-silicone copolymers, silicone-(meth)acrylic copolymers, composites of silicone and (meth)acrylic acid, composites of alkyl (meth)acrylate-butadiene-styrene and silicone, and composites of alkyl (meth)acrylate and silicone.

[0236] In addition, as the organic fine particles, organic fine particles having a core-shell structure and having different compositions of the core layer and the shell layer may be used. Examples of core-shell organic fine particles include particles having a silicone-acrylic rubber as a core and grafted with an acrylic resin, and particles obtained by grafting an acrylic resin onto an acrylic copolymer.

[0237] These organic fillers may be used alone or in combination of two or more.

[0238] The inorganic filler can adjust the thermal expansion coefficient of the epoxy resin composition of the present embodiment. Therefore, the inclusion of the inorganic filler tends to contribute to improvement in heat resistance and moisture resistance when the epoxy resin composition of the present embodiment is used as an underfill material.

[0239] Examples of inorganic fillers include, but are not limited to, silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium oxide, aluminum oxide (alumina), fused silica (such as fused spherical silica and fused crushed silica), synthetic silica, and crystalline silica; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates such as barium sulfate and calcium sulfate; sulfites such as calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; and nitrides such as aluminum nitride, boron nitride, and silicon nitride.

[0240] Among these, from the viewpoint of being able to improve heat resistance, moisture resistance and strength, preferably fused silica, crystalline silica and synthetic silica powder, in addition, preferably any one of alumina and boron nitride. By using them, the thermal linear expansion coefficient can be suppressed, and therefore, improvement in the cold and hot cycle test can be expected.

[0241] The shape of the inorganic filler is not particularly limited, and may be any of, for example, an irregular shape, a spherical shape, and a scale shape.

[0242] These inorganic fillers may be used alone or in combination of two or more.

[0243] Examples of the pigment include, but are not limited to, kaolin, alumina trihydrate, aluminum hydroxide, chalk powder, gypsum, calcium carbonate, antimony trioxide, silicon dioxide, aerosol, lithopone, barite, and titanium dioxide.

[0244] Examples of the dye include, but are not limited to, dyes derived from plants such as madder and indigo; natural dyes such as dyes derived from minerals such as loess and laterite; synthetic dyes such as alizarin and indigo; and fluorescent dyes.

[0245] Examples of the flow regulator include, but are not limited to, organic silane compounds such as silane coupling agents; organic titanium compounds such as titanium tetraisopropoxide and diisopropoxybis(acetylacetonate)titanium; and organic zirconium compounds such as zirconium tetra-n-butoxide and zirconium tetraacetylacetonate.

[0246] Examples of thickeners include, but are not limited to, animal-based thickeners such as gelatin; plant-based thickeners such as polysaccharides and cellulose; and chemically synthesized thickeners such as polyacrylic acid-based thickeners, modified polyacrylic acid-based thickeners, polyether-based thickeners, urethane-modified polyether-based thickeners and carboxymethyl cellulose.

[0247] Examples of the release agent include, but are not limited to, fluorine-based release agents, silicone-based release agents, and acrylic-based release agents composed of a copolymer of glycidyl (meth)acrylate and a linear alkyl (meth)acrylate having 16 to 22 carbon atoms.

[0248] Examples of the wetting agent include, but are not limited to, unsaturated polyester copolymer-based wetting agents having an acidic group such as acrylic polyphosphate ester.

[0249] Examples of flame retardants include, but are not limited to, metal hydroxides such as aluminum hydroxide and magnesium hydroxide; halogen-based flame retardants such as chlorine compounds and bromine compounds; phosphorus-based flame retardants such as condensed phosphate esters; antimony-based flame retardants such as antimony trioxide and antimony pentoxide; and inorganic oxides such as silicon dioxide.

[0250] Examples of surfactants include, but are not limited to, anionic surfactants such as alkylbenzene sulfonates and alkyl polyoxyethylene sulfates; cationic surfactants such as alkyl dimethyl ammonium salts; amphoteric surfactants such as alkyl dimethyl amine oxides and alkyl carboxy betaines; and nonionic surfactants such as linear alcohols having 25 or more carbon atoms and fatty acid esters.

[0251] Resins other than epoxy resins are not limited to the following, and examples thereof include silicone resins, phenolic resins, phenoxy resins, polyvinyl butyral resins, polyvinyl acetal resins, polyacrylic resins, polyimide resins; and elastomers having functional groups such as carboxyl, hydroxyl, vinyl and amino groups.

[0252] [Method for producing epoxy resin composition]

[0253] The method for producing the epoxy resin composition of the present embodiment has the following steps: a step of obtaining a mixture of the epoxy resin curing agent having the core (A) and the layer (B) of the present embodiment described above, and the epoxy resin (C). The steps for obtaining the mixture are not limited to the following, and examples thereof include:

[0254] (1) Step of adding epoxy resin (C) to the epoxy resin curing agent of the present embodiment

[0255] (2) Step of adding the epoxy resin curing agent of the present embodiment to the epoxy resin (C)

[0256] (3) A step of adding an epoxy resin (C) to a masterbatch obtained by integrating the epoxy resin curing agent of the present embodiment with a dispersion medium.

[0257] The mixing method included in the method for producing the epoxy resin composition of the present embodiment is also not particularly limited, and can be appropriately selected from, for example, a method using a planetary mixer, a method using a three-roll mill, etc. The method for producing the epoxy resin curing agent of the present embodiment is as described above.

[0258] In addition, the epoxy resin composition of the present embodiment is regarded as a masterbatch type epoxy resin curing agent composition, and an epoxy resin (C) and other additive components are added to the masterbatch type epoxy resin curing agent composition and mixed. The epoxy resin composition obtained is also included in the present embodiment.

[0259] Examples of the mixing method include a method of mixing thoroughly until the mixture is uniform using a mixing roll such as a three-roll mill, a disperser, a planetary mixer, a kneader, an extruder, or the like.

[0260] The epoxy resin curing agent, epoxy resin composition and epoxy resin composition preparation liquid for film described later of the present embodiment can be subjected to heat treatment at a temperature of 30°C to 80°C for 1 to 168 hours. There is no particular limitation on the heating method, and examples thereof include methods of heating with an oven, an incubator, a water bath, an oil bath, etc. In addition, the temperature history is not particularly limited, and for example, the temperature can be raised in stages or all at once. It should be noted that when the epoxy resin curing agent is heated, after the formation reaction of layer (B) is completed, the epoxy resin curing agent is heated after being left to stand in an environment below 5 to 12°C for more than 8 hours.

[0261] [Specific embodiment of epoxy resin composition]

[0262] The epoxy resin composition of this embodiment is suitable for, for example, bottom filling materials, sealing materials for electrical and electronic components such as relay sealing materials, conductive materials such as conductive pastes, thermally conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, impregnation fixing materials for motor coils, etc., but is not limited to the above.

[0263] In addition to the above, the epoxy resin composition of this embodiment is also suitable for, for example, interlayer insulating films, film-type solder resists, sealing sheets, conductive films, anisotropic conductive films, thermal conductive films, etc., but is not limited to the above.

[0264] Regarding the above-mentioned uses, one epoxy resin composition of the present embodiment can be used for multiple uses at the same time. As such an example, when the epoxy resin composition of the present embodiment contains silver particles as a filler, the conductive material obtained from the epoxy resin composition can also become a thermal conductive material, but it is not limited to the above.

[0265] As described above, the epoxy resin composition of the present embodiment can be preferably used as a sealing material, a conductive material, a thermally conductive material, an insulating material, an adhesive for camera modules, an adhesive for structure, a matrix resin for fiber-reinforced plastics, an impregnation fixing material, an interlayer insulating film, a film-type solder resist, a sealing sheet, a conductive film, an anisotropic conductive film and / or a thermally conductive film. In other words, the sealing material, conductive material, thermally conductive material, insulating material, adhesive for camera modules, adhesive for structure, matrix resin for fiber-reinforced plastics, an impregnation fixing material, an interlayer insulating film, a film-type solder resist, a sealing sheet, a conductive film, an anisotropic conductive film and a thermally conductive film of the present embodiment all include the epoxy resin composition of the present embodiment (the epoxy resin curing agent of the present embodiment).

[0266] For example, when the epoxy resin composition of this embodiment is used as an underfill material, it requires stability against heating for rapid penetration between the semiconductor chip and the substrate and excellent curing properties at 120°C to 150°C. The epoxy resin composition of this embodiment contains an epoxy resin curing agent and can therefore have all of these properties at the same time.

[0267] The conductive material may include solder particles, nickel particles, nano-sized metal crystals, particles obtained by coating the metal surface with other metals, copper and silver gradient particles, and other metal particles and solvents as conductive particles. The epoxy resin curing agent of this embodiment has a strong layer (B), so it has resistance to metal particles and also has resistance to solvents. Therefore, the epoxy resin composition including the epoxy resin curing agent of this embodiment can provide a conductive material with excellent stability.

[0268] In the thermally conductive material, metals such as silver with high thermal conductivity, metal oxides such as zinc oxide, ceramics such as boron nitride, aluminum nitride, and aluminum oxide, and inorganic fillers such as silicon dioxide are integrated with the curing agent. Thermally conductive and electrically conductive materials require stability during storage. It is difficult to impart excellent stability when the curing agent and the liquid component are not isolated. Even if there is a covering layer that isolates the curing agent component from the liquid component, if its strength is insufficient, it will be destroyed when it collides with the filler. The epoxy resin composition containing the epoxy resin curing agent of this embodiment has excellent properties in these aspects and can provide a stable thermally conductive material.

[0269] Typical examples of structural adhesives include automotive structural adhesives, and there are cases where the adhesive is applied and placed under high temperature and high humidity, and in this case, excellent stability to both heat and moisture is required. The epoxy resin composition containing the epoxy resin curing agent of this embodiment can provide a structural adhesive having excellent stability to both heat and moisture.

[0270] In the adhesive for camera modules, for example, when actively aligning a lens holder with an electronic component equipped with an image sensor such as a CMOS sensor, a dual-curing adhesive that is cured by both light and heat is used, and the dual-curing adhesive contains both an epoxy resin and an acrylic resin. The epoxy resin composition containing the epoxy resin curing agent of this embodiment can also provide an adhesive for camera modules having sufficient stability and reactivity when containing both.

[0271] Matrix resins for fiber-reinforced plastics and impregnation fixing materials for motor coils are required to have performance in the process from impregnation to curing, that is, permeability into gaps between fine fibers or coils, stability during penetration, and curability. The epoxy resin composition containing the epoxy resin curing agent of this embodiment can have all of these characteristics and is therefore suitable.

[0272] [Film comprising the epoxy resin composition of the present embodiment]

[0273] A film having a resin composition layer containing the epoxy resin curing agent and / or the epoxy resin composition of this embodiment is also included in this embodiment.

[0274] In this case, the epoxy resin composition can also function as an epoxy resin curing agent or curing accelerator. The epoxy resin composition of this embodiment has excellent solvent resistance and is suitable for a thin film.

[0275] The film of this embodiment includes, for example, a predetermined support and a resin composition layer formed on the support using an epoxy resin composition preparation liquid described later, and may include a protective layer on the surface of the resin composition layer opposite to the support, if necessary.

[0276] The support is preferably a material that can withstand the temperature at which the organic solvent is dried. Such a support is not limited to the following, and examples thereof include polyethylene terephthalate films, polyvinyl alcohol films, polyvinyl chloride films, vinyl chloride copolymer films, polyvinylidene chloride films, vinylidene chloride copolymer films, polymethyl methacrylate copolymer films, polystyrene films, polyacrylonitrile films, styrene copolymer films, polyamide films, and cellulose derivative films.

[0277] As these films, stretched films may be used as necessary.

[0278] As the protective layer, preferably a material that can fully maintain the smoothness of the surface of the resin composition layer is used. As such a protective layer, it is not limited to the following, and preferably a polyethylene film, a polypropylene film, a polyethylene terephthalate film treated for easy peeling, an oriented polypropylene film, etc. can be used.

[0279] [Method for preparing epoxy resin composition preparation liquid for film]

[0280] As a method for preparing an epoxy resin composition preparation liquid for forming a resin composition layer of a thin film, the following method can be cited, for example: the epoxy resin curing agent and / or epoxy resin composition of this embodiment is mixed with other additives, a polymer for forming a thin film, etc., and then an organic solvent is added, and mixing is carried out using a planetary mixer or the like.

[0281] As the film-forming polymer, all polymers that have the effect of suppressing cracks, shrinkage, and excessive flow and maintaining the shape of the film when the epoxy resin composition solution is applied and the organic solvent is dried to form a film can be used. Such film-forming polymers are not limited to the following, and examples thereof include phenoxy resins, polyvinyl butyral resins, polyvinyl acetal resins, polyacrylic resins, polyimide resins, and elastomers having functional groups such as carboxyl, hydroxyl, vinyl, and amino groups. Film-forming polymers are sometimes also referred to as binder polymers.

[0282] There are no particular restrictions on the organic solvent, and known organic solvents can be used. Examples include, but are not limited to, hydrocarbons such as toluene, xylene, cyclohexane, mineral spirits, and naphtha; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone; esters such as ethyl acetate, n-butyl acetate, and propylene glycol monomethyl ethyl ether acetate; alcohols such as methanol, isopropyl alcohol, n-butanol, butyl cellosolve, and butyl carbitol; and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0283] [Thin film manufacturing method]

[0284] The film of the present embodiment can be produced by sequentially laminating a support, a resin composition layer, and, if necessary, a protective layer.

[0285] As a method for laminating the support, the resin composition layer, and the protective layer, a known method can be adopted.

[0286] For example, a prepared solution of an epoxy resin composition and an organic solvent comprising the present embodiment is prepared. First, a known method such as an applicator and a rod coater is used to apply it on a support and dry it to form a resin composition layer on the support. As a drying method, it is not particularly limited, and examples thereof include an oven, hot air blowing, etc. In addition, the drying temperature and time are not particularly limited. From the viewpoint of fully removing the solvent and suppressing the deformation of the support caused by excessive heating and the residual reaction of the resin composition layer during drying, it is preferably dried within a temperature range of 50°C to 160°C and within a drying time of 1 minute to 30 minutes, and more preferably within 80°C to 150°C and within 3 minutes to 25 minutes. It should be noted that, with respect to the drying temperature, it can be a fixed temperature or a temperature gradient can be applied. Then, a protective layer is laminated on the formed resin composition layer as needed, so that a film can be manufactured.

[0287] [Specific aspects of the film comprising the epoxy resin composition of the present embodiment]

[0288] The film including the epoxy resin composition of this embodiment can be used as, for example, an interlayer insulating film, a film-type solder resist, a sealing sheet, a conductive film, an anisotropic conductive film, a thermal conductive film, etc., but is not limited thereto.

[0289] The epoxy resin composition of the present embodiment is excellent in solvent resistance and storage stability, and therefore, the coating time of the epoxy resin composition preparation solution for a film containing the composition can be prolonged, and the shelf life of the obtained film can be prolonged.

[0290] Furthermore, since the epoxy resin composition of the present embodiment has excellent curability at 150° C. or lower, the film of the present embodiment also has excellent curability.

[0291] The above characteristics are commonly required for interlayer insulating films, film-type solder resists, sealing sheets, conductive films, anisotropic conductive films, and thermally conductive films. Therefore, the film of this embodiment is suitable for these aspects.

[0292] Example

[0293] The present embodiment will be described below with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.

[0294] In addition, unless otherwise specified, the following "parts" and "%" are based on mass.

[0295] [Production of a core (A) comprising a nitrogen-containing compound]

[0296] (Production Example 1)

[0297] One equivalent (in terms of epoxy group) of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm) and one equivalent (in terms of active hydrogen) of 2-methylimidazole were reacted at 80° C. in a 1:1 mixed solvent of n-butanol and toluene. Unreacted 2-methylimidazole was then distilled off together with the solvent under reduced pressure to obtain a substance 1 which was solid at 25° C.

[0298] Next, the above substance 1 was pulverized by a jet mill and then classified by a classifier to obtain a specific surface area value of 3.71 m 2 / g, average particle size under sieve D 50 2.63μm, with D 99 / D 50 The core component 1 has a particle size distribution of 5.5 and contains 0.005 mass % of 2-methylimidazole (abbreviated as "2MI" in the table).

[0299] About D 50 and D 99Based on the Stoke's particle size measured by a laser diffraction / light scattering method using a particle size distribution meter (manufactured by Horiba, Ltd., "HORIBA LA-920"), the particle size at which the cumulative percentage under the sieve of the core (A) is 50% is defined as D. 50 , the particle size at which the cumulative percentage of the core (A) under the sieve is 99% is set as D 99 (The same applies to the following manufacturing examples).

[0300] The specific surface area value was measured using a fully automatic BET specific surface area measuring apparatus HMmodel-1201 manufactured by MOUNTECH Co., Ltd., using a mixed gas of N2 / He = 30 / 70 (volume ratio) as the adsorption gas (the same applies to the following production examples).

[0301] (Production Example 2)

[0302] The core component 1 was used, and KRYPTRON ORB manufactured by EARTHTECHNICA CO., LTD. was used in an environment of temperature 10°C and humidity 30% at a rotation speed of 13500 rpm, a supply speed of 10 kg / hr, and a wind volume of 3 m 3 / min for shape correction. A cyclone collector and bag filter were added to the classifier for classification, and the specific surface area value was 2.51m 2 / g、D 50 2.80μm, with D 99 / D 50 The core component 2 has a particle size distribution of 3.8 and contains 0.005 mass % of 2-methylimidazole.

[0303] (Production Example 3)

[0304] 1 equivalent (in terms of epoxy group) of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm) and 1.2 equivalents (in terms of active hydrogen) of 2-methylimidazole were reacted at 80° C. in a 1:1 mixed solvent of n-butanol and toluene. Then, the excess 2-methylimidazole was distilled off together with the solvent under reduced pressure to obtain a substance 2 which was solid at 25° C.

[0305] Next, the substance 2 was crushed with a turbine grinder and then classified with a classifier to obtain a specific surface area value of 3.61 m 2 / g, average particle size under sieve D 50 2.41μm, with D 99 / D 50 The core component 3 has a particle size distribution of 5.1 and contains 0.2 mass % of 2-methylimidazole.

[0306] (Production Example 4)

[0307] One equivalent (in terms of epoxy group) of bisphenol F epoxy resin E-2 (BisF resin epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm) and one equivalent (in terms of active hydrogen) of 2-methylimidazole were reacted in a 1:1 mixed solvent of n-butanol and toluene at 80° C. Then, the excess 2-methylimidazole was distilled off together with the solvent under reduced pressure to obtain a substance 3 which was solid at 25° C.

[0308] The obtained substance 3 was pulverized by a turbine grinder to obtain a specific surface area value of 3.91 m 2 / g, average particle size under sieve D 50 2.55μm, with D 99 / D 50 The core component 4 has a particle size distribution of 4.0 and contains 0.01 mass % of 2-methylimidazole.

[0309] (Production Example 5)

[0310] One equivalent (in terms of epoxy group) of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm) and one equivalent of diethylenetriamine (abbreviated as "DETA" in the table) were reacted at 80° C. in a 1:1 mixed solvent of xylene and isopropanol. Then, the excess diethylenetriamine was distilled off together with the solvent under reduced pressure to obtain a solid substance 4 at 25° C.

[0311] 45 g of the above-mentioned substance 4, 45 g of the substance 1 and 11 g of 1,4-diazabicyclo[2.2.2]octane (abbreviated as "DABCO" in the table) were melt-mixed at 150°C to obtain substance 5 which was solid at 25°C.

[0312] Next, the substance 5 was crushed with a turbine grinder and then classified with a classifier to obtain a specific surface area value of 2.69 m 2 / g, average particle size under sieve D 50 2.88μm, with D 99 / D 50 The core component 5 has a particle size distribution of 4.7, contains 10% by mass of 1,4-diazabicyclo[2.2.2]octane, and further contains 0.1% by mass of diethylenetriamine and 2-methylimidazole in total.

[0313] (Production Example 6)

[0314] The above substance 1 was crushed by a jet mill and then classified by a classifier to obtain a specific surface area value of 4.32 m 2 / g, average particle size under sieve D 50 2.27μm, with D99 / D 50 The core component 6 has a particle size distribution of 3.4 and contains 0.005 mass % of 2-methylimidazole.

[0315] [Example 1]

[0316] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 1 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, and then reacted at 55°C for 5 hours. Then, the mixture was allowed to stand for 12 hours (standing step) at 9°C to obtain a masterbatch type epoxy resin curing agent composition 1. It should be noted that temperature monitoring was performed during the above-mentioned standing step to confirm the lowest temperature T from the start time t1 to the end time t2. L With the maximum temperature T H The difference was 4° C. or less. That is, it was confirmed that the temperature change when left to stand for 12 hours under the condition set at 9° C. was within the range of 9° C.±2° C. (hereinafter, the temperature change in the standing step was similarly confirmed.).

[0317] (Evaluation of dyeability of layer (B))

[0318] First, 10.6 mL of a main agent (Quetol 812, manufactured by Nissin EM Co., Ltd.), 9.4 mL of a curing agent (methyl nadic anhydride: MNA, manufactured by Nissin EM Co., Ltd.), and 0.34 mL of a reaction accelerator (2,4,6-tris(dimethylaminomethyl)phenol, manufactured by Nissin EM Co., Ltd.: DMP-30) were mixed, stirred for 15 minutes with a stirrer, and then air bubbles were removed by vacuum degassing to obtain an epoxy resin composition for dyeing.

[0319] Next, toluene was added to the masterbatch type epoxy resin hardener composition 1, and the epoxy resin and the hardener component were separated by a centrifugal separator, and the hardener component was collected and dried, thereby obtaining an epoxy resin hardener 1.

[0320] The obtained epoxy resin curing agent 1 is allowed to coexist with ruthenium tetroxide in a sealed and light-proof container at room temperature and atmospheric pressure for 10 minutes for electron staining, and then mixed with the above-mentioned epoxy resin composition for staining, and cured at 40°C for 42 hours. The obtained cured product embedded with the epoxy resin curing agent 1 is sliced ​​into 80nm slices using an ultrathin slicer, and then the slices are allowed to coexist with osmium tetroxide in a sealed and light-proof container at room temperature and atmospheric pressure for 2 hours to obtain an observation sample electron-stained with osmium tetroxide vapor. The observation sample is irradiated with an electron beam using a TEM, the focus is adjusted to align with the sample, and observation is performed at an acceleration voltage of 120kV and a magnification of 30,000 times to obtain an image 1 of the core (A) and the layer (B).

[0321] The obtained image 1 was read using the image analysis software ImageJ (ImageJ 1.53t Java 1.8.0_345 (64-bit)), and after applying a median filter (Radius 2.0 pixels), a line segment was drawn from the outermost portion of the layer (B) to include the boundary between the core (A) and the layer (B), thereby obtaining image 1' ( Figure 1 ). The brightness is plotted along this line segment to obtain a curve Figure 1 ( Figure 2 ).curve Figure 1 In the figure, the vertical axis represents brightness, and the horizontal axis represents the distance between the outermost side and the end of the layer (B) in the above-mentioned line segment (the same applies to subsequent figures).

[0322] According to the obtained image 1' and curve Figure 1 When a brightness curve graph from the outermost portion of layer (B) to the boundary between layer (B) and core (A) was obtained, it was confirmed that the interior of layer (B) of epoxy resin curing agent 1 had an area with a brightness higher than that of the outermost portion and the above-mentioned boundary.

[0323] [Example 2]

[0324] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 2200 parts by mass of core component 2 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 2. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0325] For the masterbatch type epoxy resin curing agent composition 2, the dyeability of the epoxy resin curing agent 2 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the interior of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0326] [Example 3]

[0327] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 3 and 10 parts by mass of core surface coating material C-2 (CORONATE T100 manufactured by Tosoh Corporation) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 3. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0328] Regarding the masterbatch type epoxy resin curing agent composition 3, the dyeing property of the epoxy resin curing agent 3 was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. That is, in the image 2 obtained by performing image analysis on the TEM observation image of the epoxy resin curing agent 3, a line was drawn at a predetermined position in order to confirm the dyeing property, and an image 2′ ( Figure 3 ). The brightness is plotted along this line segment to obtain a curve Figure 2 ( Figure 4 ). According to image 2' and curve Figure 2 When obtaining a brightness curve from the outermost part of layer (B) to the boundary between layer (B) and core (A), it is confirmed that the interior of layer (B) of epoxy resin curing agent 3 has an area with higher brightness than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0329] [Example 4]

[0330] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 4, 4 parts by mass of core surface coating material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.), and 3 parts by mass of core surface coating material C-3 (Duranate TPA-100 manufactured by Asahi Kasei Corporation) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 4. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0331] For the masterbatch type epoxy resin curing agent composition 4, the dyeing property of the epoxy resin curing agent 4 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. That is, in the image I obtained by performing image analysis on the TEM observation image of the epoxy resin curing agent 4, a line was drawn at a predetermined position in order to confirm the dyeing property, and an image I' ( Figure 5 ). The brightness is plotted along this line segment to obtain a graph G ( Figure 6 ). According to the image I' and the graph G, when a brightness graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) is obtained, it is confirmed that the inside of the layer (B) of the epoxy resin curing agent 4 has a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary. Figure 5 In the example, the boundary between layer (B) and the epoxy resin composition region for dyeing is seen to be wavy or wrinkled, indicating that the surface of layer (B) is a rough surface. Figure 5 (Epoxy resin curing agent 4) and Figure 1 (Epoxy resin curing agent 1) and Figure 3 (Epoxy resin curing agent 3) for comparison, Figure 1 , 3 In the graph, the boundary between the layer (B) and the epoxy resin composition region for dyeing appears to be linear, indicating that the surface of the layer (B) in the epoxy resin curing agents 1 and 3 is smoother than that of the epoxy resin curing agent 4 described later.

[0332] [Example 5]

[0333] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 120 parts by mass of core component 5 and 10 parts by mass of core surface coating material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 5. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0334] For the masterbatch type epoxy resin curing agent composition 5, the dyeability of the epoxy resin curing agent 5 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the interior of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0335] [Example 6]

[0336] 90 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 90 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 20 parts by mass of naphthalene epoxy resin E-3 (epoxy equivalent 142 g / eq, total chlorine content 700 ppm, "HP4032D" manufactured by DIC Corporation), 1100 parts by mass of core component 1, and 10 parts by mass of core surface coating material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 6. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0337] For the masterbatch type epoxy resin curing agent composition 6, the dyeability of the epoxy resin curing agent 6 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the interior of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0338] [Example 7]

[0339] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 1 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand at 6° C. for 8 hours to obtain a masterbatch type epoxy resin curing agent composition 7. It should be noted that the temperature change when allowed to stand at 6° C. for 8 hours was confirmed to be within the range of 6° C.±2° C.

[0340] For the masterbatch type epoxy resin curing agent composition 7, the dyeability of the epoxy resin curing agent 7 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the interior of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0341] [Example 8]

[0342] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 1 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand at 12° C. for 24 hours to obtain a masterbatch type epoxy resin curing agent composition 8. It should be noted that the temperature change when allowed to stand at 12° C. for 24 hours was confirmed to be within the range of 12° C. ± 2° C.

[0343] For the masterbatch type epoxy resin curing agent composition 8, the dyeability of the epoxy resin curing agent 8 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the interior of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0344] [Example 9]

[0345] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 6 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 9° C. to obtain a masterbatch type epoxy resin curing agent composition 9. It should be noted that the temperature change when allowed to stand for 12 hours at 9° C. was confirmed to be within the range of 9° C.±2° C.

[0346] For the masterbatch type epoxy resin curing agent composition 9, the dyeability of the epoxy resin curing agent 9 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A) was obtained, it was confirmed that the inside of the layer (B) had a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0347] [Comparative Example 1]

[0348] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 1 and 10 parts by mass of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand for 12 hours at 25° C. to obtain masterbatch type epoxy resin curing agent R-1. It should be noted that the temperature change when allowed to stand for 12 hours at 25° C. was confirmed to be within the range of 25° C.±2° C.

[0349] The dyeing property of the masterbatch type epoxy resin curing agent composition R-1 was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. That is, in the image 3 obtained by image analysis of the TEM observation image of the epoxy resin curing agent 3, a line was drawn at a predetermined position in order to confirm the dyeing property, and an image 3' ( Figure 7 ). The brightness is plotted along this line segment to obtain a curve Figure 3 ( Figure 8 ). According to image 3' and curve Figure 3When obtaining a brightness curve from the outermost part of layer (B) to the boundary between layer (B) and core (A), it was confirmed that the interior of layer (B) of epoxy resin curing agent R-1 did not have an area with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0350] [Comparative Example 2]

[0351] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by mass of core component 1 and 10 parts by mass of core surface coating material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand at 50° C. for 24 hours to obtain epoxy resin curing agent R-2 of Comparative Example 2. It should be noted that the temperature change when allowed to stand at 50° C. for 24 hours was confirmed to be within the range of 50° C.±2° C.

[0352] For the masterbatch type epoxy resin curing agent composition R-2, the dyeability of the epoxy resin curing agent R-2 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of layer (B) to the boundary between layer (B) and core (A) was obtained, it was confirmed that the interior of layer (B) did not have a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0353] [Comparative Example 3]

[0354] 100 parts by mass of bisphenol A epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by mass of bisphenol F epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 1100 parts by mass of core component 1 and 20 parts by mass of core surface coating material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.) were dispersed and mixed, reacted at 55° C. for 5 hours, and then allowed to stand at 25° C. for 12 hours to obtain epoxy resin curing agent R-3 of Comparative Example 3. It should be noted that the temperature change when allowed to stand at 25° C. for 12 hours was confirmed to be within the range of 25° C.±2° C.

[0355] For the masterbatch type epoxy resin curing agent composition R-3, the dyeability of the epoxy resin curing agent R-3 contained therein was confirmed in the same manner as the masterbatch type epoxy resin curing agent composition 1. The result was that when a brightness curve graph from the outermost part of layer (B) to the boundary between layer (B) and core (A) was obtained, it was confirmed that the interior of layer (B) did not have a region with a brightness higher than the brightness of the outermost part and the brightness of the above-mentioned boundary.

[0356] [Evaluation method of characteristics]

[0357] (Evaluation of the stability of low molecular weight epoxy compounds)

[0358] (Method for preparing epoxy resin composition for evaluating stability of low molecular weight epoxy compounds)

[0359] After weighing 30 parts of the masterbatch type epoxy resin curing agent composition described in Examples 1 to 9 and Comparative Examples 1 to 3, 100 parts of jER828 (manufactured by Mitsubishi Chemical Corporation) and 30 parts of a low molecular weight epoxy compound o-CGE (o-cresyl glycidyl ether; viscosity at 25°C, 7 mPa·s; manufactured by Sigma-Aldrich), these components were stirred for 2 minutes and degassed for 3 minutes using a bubble-free kneader, and mixed to prepare an epoxy resin composition for use in evaluating the stability of the low molecular weight epoxy compound.

[0360] (Stability to low molecular weight epoxy compounds)

[0361] The initial viscosity of the epoxy resin composition for stability evaluation of the low molecular weight epoxy compound immediately after preparation and the post-storage viscosity of the epoxy resin composition for stability evaluation after being left at 40°C for 21 days were measured at room temperature (25°C) using an E-type viscometer, and the post-storage viscosity ratio was calculated by the following mathematical formula (2).

[0362] Viscosity ratio after storage = viscosity after storage / initial viscosity ... Formula (2)

[0363] The viscosity ratio after storage was evaluated according to the following criteria.

[0364] 0: 1.0 times ≤ viscosity ratio after storage < 1.3 times

[0365] △: 1.3 times ≤ viscosity ratio after storage < 2.0 times

[0366] ×: 2.0 times ≤ viscosity ratio after storage

[0367] (Reactivity of Epoxy Resin Composition Containing Low Molecular Epoxy Compound)

[0368] About 10 mg of an epoxy resin composition (uncured state) for evaluating the stability of a low molecular weight epoxy compound was weighed and heated from 25°C to 250°C at a rate of 20°C / min using DSC EXSTER7020 (manufactured by Hitachi High-Tech Corporation) to obtain a DSC curve. The temperature at the point where the heat flow reaches the maximum is taken as the DSC exotherm peak temperature.

[0369] Evaluation was performed based on the exothermic peak temperature according to the following criteria.

[0370] ◎◎: Exothermic peak temperature ≤ 120℃

[0371] ◎: 120℃<Exothermic peak temperature≤130℃

[0372] 0:130℃<Exothermic peak temperature≤140℃

[0373] △: 140℃<Exothermic peak temperature≤150℃

[0374] ×: 150℃<exothermic peak temperature

[0375] (Evaluation of the stability of MEK)

[0376] (Method for preparing epoxy resin composition for evaluating stability of MEK)

[0377] 50 parts by mass of jER828 (manufactured by Mitsubishi Chemical), 50 parts by mass of PKHB (manufactured by Gabriel Phenoxies) and 100 parts by mass of MEK were mixed and dissolved to obtain a liquid, and 15 parts by mass of the masterbatch type epoxy resin curing agent composition described in Examples 1 to 9 and Comparative Examples 1 to 3 was added to obtain an epoxy resin composition for evaluating the stability of MEK.

[0378] (Stability to MEK)

[0379] The initial viscosity of the epoxy resin composition for stability evaluation with respect to MEK immediately after preparation and the post-storage viscosity of the epoxy resin composition for stability evaluation after being left at 25° C. for 24 hours were measured at room temperature (25° C.) using an E-type viscometer, and the post-storage viscosity ratio was calculated by the following mathematical formula (3).

[0380] Viscosity ratio after storage = viscosity after storage / initial viscosity ... Formula (3)

[0381] The viscosity ratio after storage was evaluated according to the following criteria.

[0382] 0: 1.0 times ≤ viscosity ratio after storage < 2.0 times

[0383] △: 2.0 times ≤ viscosity ratio after storage < 3.0 times

[0384] ×: 3.0 times ≤ viscosity ratio after storage

[0385] (Evaluation of the stability of low molecular weight acrylic compounds)

[0386] (Method for preparing epoxy resin composition for evaluating stability of low molecular weight acrylic compounds)

[0387] After weighing 50 parts by mass of the masterbatch type epoxy resin curing agent composition described in Examples 1 to 9 and Comparative Examples 1 to 3, 100 parts by mass of jER828 (manufactured by Mitsubishi Chemical Corporation) and 50 parts by mass of epoxy acrylate (Epoxy Ester 3000A manufactured by Kyoeisha Chemical Co., Ltd.), these components were stirred for 2 minutes and degassed for 3 minutes using a bubble-free kneader, and then mixed to prepare an epoxy resin composition for stability evaluation of low molecular weight acrylic compounds.

[0388] (Stability to low molecular weight acrylic compounds)

[0389] The initial viscosity of the epoxy resin composition for stability evaluation of the low molecular weight acrylic compound immediately after preparation and the post-storage viscosity of the epoxy resin composition for stability evaluation after being left at 40° C. for 7 days were measured at room temperature (25° C.) using an E-type viscometer, and the post-storage viscosity ratio was calculated by the following mathematical formula (4).

[0390] Viscosity ratio after storage = viscosity after storage / initial viscosity ... Formula (4)

[0391] The viscosity ratio after storage was evaluated according to the following criteria.

[0392] 0:1.0 times≤Viscosity ratio after storage<1.5 times

[0393] △: 1.5 times ≤ viscosity ratio after storage < 2.0 times

[0394] ×: 2.0 times ≤ viscosity ratio after storage

[0395] (Reactivity of Epoxy Resin Composition Containing Low Molecular Weight Acrylic Compound)

[0396] About 10 mg of an epoxy resin composition (uncured state) for evaluating the stability of low molecular weight acrylic compounds was weighed and heated from 25°C to 250°C at a rate of 20°C / min using EXSTER7020 (manufactured by Hitachi High-Technologies Corporation) to obtain a DSC curve. The temperature at the point where the heat flow reaches the maximum is taken as the DSC exotherm peak temperature.

[0397] Evaluation was performed based on the exothermic peak temperature according to the following criteria.

[0398] ◎◎: Exothermic peak temperature ≤ 120℃

[0399] ◎: 120℃<Exothermic peak temperature≤130℃

[0400] 0:130℃<Exothermic peak temperature≤140℃

[0401] △: 140℃<Exothermic peak temperature≤150℃

[0402] ×: 150℃<exothermic peak temperature

[0403] (Appearance evaluation of small area)

[0404] (Method for preparing epoxy resin composition for micro-region appearance evaluation)

[0405] 15 parts by mass of the masterbatch epoxy resin curing agent composition described in Examples 1 to 9 and Comparative Examples 1 to 3, 30 parts by mass of jER828 (manufactured by Mitsubishi Chemical Corporation), 5 parts by mass of a low molecular weight epoxy compound o-CGE (o-cresyl glycidyl ether; viscosity at 25° C.: 7 mPa·s; manufactured by Sigma-Aldrich) and SO-E2 (spherical silica manufactured by Admatechs; D) as a filler were weighed. 50 =0.8 μm) were added, and then these components were stirred for 2 minutes and degassed for 3 minutes using a bubble-free kneader and mixed to prepare an epoxy resin composition for appearance evaluation of a micro region.

[0406] (Appearance evaluation of small area)

[0407] The epoxy resin composition used for the appearance evaluation of the micro area was kept in an oven at 180°C for 1 hour to obtain a cured product. The cured product was cut with a diamond tool, polished with sandpaper, and gold was vapor-deposited on the surface. The polished surface was observed with a SEM at a magnification of 1000 times. The obtained SEM image was binarized, and the area ratio of the area without filler with a circle equivalent diameter of 3 μm or more was calculated.

[0408] The area ratio of the region without filler was evaluated according to the following criteria.

[0409] ○: Less than 5%

[0410] ×: 5% or more

[0411] Table 1 shows the weight % of the low molecular weight amine having a molecular weight of 50 to 300 contained in the core (A) of Examples 1 to 9 and Comparative Examples 1 to 3, the dyeability of the layer (B), and the properties of the epoxy resin compositions prepared in each evaluation item.

[0412] In addition, the dyeability of layer (B) was evaluated according to the following criteria.

[0413] ○: When a brightness curve graph is obtained from the outermost portion of layer (B) to the boundary between layer (B) and core (A), the inner portion of layer (B) has a region with a brightness higher than that of the outermost portion and the above-mentioned boundary.

[0414] ×: When a brightness curve from the outermost portion of layer (B) to the boundary between layer (B) and core (A) is obtained, the inner portion of layer (B) does not have a region having a brightness higher than that of the outermost portion and the above-mentioned boundary.

[0415] [Table 1]

[0416]

[0417] By comparing the embodiments and the comparative examples, it can be seen that when a brightness curve graph is obtained from the outermost part of layer (B) to the boundary between layer (B) and core (A), epoxy resin curing agents 1 to 9 having a position inside layer (B) with a brightness higher than that at the outermost part and the boundary between layer (B) and core (A) have excellent stability and reactivity for low molecular weight epoxy compounds, MEK, and low molecular weight acrylic resins.

[0418] In addition, it can be seen that, in terms of the appearance of the micro region, when a brightness curve graph is obtained from the outermost portion of the layer (B) to the boundary between the layer (B) and the core (A), the appearance of the micro region is excellent because the brightness is higher inside the layer (B) than at the outermost portion and the boundary between the layer (B) and the core (A). Fig. 9 The appearance of Comparative Example 1 is shown in Fig.10 .

[0419] Here, it can be seen from the results of Comparative Examples 1 to 3 that when the masterbatch type epoxy resin curing agent composition is subjected to heat treatment and the increase and temperature of the core surface covering material are not controlled, when a brightness curve diagram is obtained from the outermost part of layer (B) to the boundary between layer (B) and core (A), an epoxy resin curing agent having a position inside layer (B) with a brightness higher than that at the outermost part and the boundary between layer (B) and core (A) cannot be obtained.

[0420] (Effect of adding ingredient (D))

[0421] To the epoxy resin composition for evaluating the stability of low molecular weight epoxy compounds using the masterbatch type epoxy resin curing agent composition of Example 1, 3 parts by mass of bisphenol A (2,3-dihydroxypropyl) glycidyl ether (manufactured by Merck) was further added as component (D), and the stability and reactivity evaluations for low molecular weight epoxy compounds were performed. As a result, the stability for low molecular weight epoxy compounds was 0, and the reactivity of the epoxy resin composition containing the low molecular weight epoxy compound was ◎◎, which shows that the reactivity was improved while maintaining the stability.

[0422] Although the present embodiment has been described above, the present invention is not limited thereto and can be appropriately modified within the scope of the gist of the invention.

[0423] Industrial Applicability

[0424] The epoxy resin curing agent and epoxy resin composition of this embodiment have excellent reactivity and stability even when low molecular weight epoxy compounds, solvents, and low molecular weight acrylic compounds coexist, and thus have excellent appearance in small areas. Therefore, they have industrial applicability in sealing materials for electrical and electronic components such as bottom filling materials, relay sealing materials, conductive materials such as conductive pastes, thermal conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber reinforced plastics, impregnation fixing materials for motor coils, etc.

[0425] In addition, the epoxy resin curing agent and epoxy resin composition of this embodiment have excellent solvent resistance and therefore have industrial applicability in film applications such as interlayer insulating films, film-type solder resists, sealing sheets, conductive films, anisotropic conductive films, and thermal conductive films.

Claims

1. An epoxy resin curing agent, comprising: A core (A) comprising a nitrogen-containing compound, and a layer (B) covering said core (A), When the epoxy resin curing agent is stained with ruthenium tetroxide and osmium tetroxide and then observed with a transmission electron microscope and a brightness curve diagram is obtained by image processing, the interior of the layer (B) contains a region with brightness α, and the brightness α is higher than the brightness β of the outermost portion of the layer (B) and the brightness γ of the boundary between the layer (B) and the core (A).

2. The epoxy resin curing agent according to claim 1, wherein The core (A) contains 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300.

3. The epoxy resin curing agent according to claim 1, wherein The core (A) includes at least one selected from the group consisting of imidazoles, aliphatic amine compounds, and cyclic amine compounds including tertiary amines.

4. The epoxy resin curing agent according to claim 1, wherein The core (A) contains an imidazole-based amine addition compound.

5. The epoxy resin curing agent according to claim 1, wherein The particle size D at which the cumulative percentage under the sieve of the core (A) is 50% 50 More than 0.3 μm and less than 12 μm.

6. The epoxy resin curing agent according to claim 5, wherein The particle size D of the core (A) having a cumulative percentage under the sieve of 99% 99 With the D 50 The ratio of D 99 / D 50 Counted as 8 or less.

7. The epoxy resin curing agent according to claim 5, wherein The specific surface area value Y (m 2 / g) multiplied by the D 50 The value obtained by measuring the relative humidity (μm) is 3.0 or more and 9.0 or less.

8. The epoxy resin curing agent according to claim 5, wherein The specific surface area value Y (m 2 / g) multiplied by the D 50 The value obtained by measuring (μm) is more than 9.0 and less than 18.

0. 9 . An epoxy resin composition comprising the epoxy resin curing agent according to claim 1 and an epoxy resin (C).

10. The epoxy resin composition according to claim 9, wherein The mass ratio of the epoxy resin curing agent to the epoxy resin (C) is 0.1:100 to 1000:100 (epoxy resin curing agent:epoxy resin (C)).

11. The epoxy resin composition according to claim 9, wherein It also contains an alcohol compound (D) represented by the following formula (1), In formula (1), X1 represents an alkylene group having a carbon number of 2 or more and 5 or less which optionally has a substituent R, and the substituents R and R1 to R5 each independently represent a hydrogen atom, an alkyl group, an unsaturated aliphatic group, an aromatic group, a substituent containing a heteroatom or a halogen atom, and herein, any of R1 to R5 can be selected to form a condensed ring compound of the same ring.

12. The epoxy resin composition according to claim 11, wherein The content of the alcohol compound (D) is 0.0001% by mass or more and 5% by mass or less based on the total amount of the epoxy resin composition.

13. The epoxy resin composition according to claim 11, wherein The alcohol compound (D) includes at least one selected from the group consisting of 3-phenoxy-1-propanol, 3-phenoxy-1,2-propanediol, 3-phenoxy-1,3-propanediol, 3-(o-tolyloxy)-1,2-propanediol, 3-(2-methoxyphenoxy)propane-1,2-diol, bisphenol A (3-hydroxypropyl) glycidyl ether and bisphenol A (2,3-dihydroxypropyl) glycidyl ether.

14. The epoxy resin composition according to claim 13, wherein The core (A) contains 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300, wherein the amine compound (a) contains at least one selected from the group consisting of imidazoles, aliphatic amine compounds, and cyclic amine compounds including tertiary amines. 15 . A sealing material comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 16 . A conductive material comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 17 . A thermally conductive material comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 18 . An insulating material comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 19 . An adhesive for a camera module, comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 .

20. A structural adhesive comprising the epoxy resin curing agent according to any one of claims 1 to 3 or the epoxy resin composition according to any one of claims 9, 11, 13 and 14.

21. A matrix resin for fiber reinforced plastics, comprising the epoxy resin curing agent according to any one of claims 1 to 3 or the epoxy resin composition according to any one of claims 9, 11, 13 and 14. 22 . An impregnation fixing material comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 .

23. An interlayer insulating film comprising the epoxy resin curing agent according to any one of claims 1 to 3 or the epoxy resin composition according to any one of claims 9, 11, 13 and 14. 24 . A thin-film solder resist comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 25 . A sealing sheet comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 26 . A conductive film comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 27 . An anisotropic conductive film comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 . 28 . A thermally conductive film comprising the epoxy resin curing agent according to claim 1 or the epoxy resin composition according to claim 9 .

29. A method for producing a dyed cured product, comprising the following steps: a step (S1) of electronically dyeing an epoxy resin curing agent having a core (A) and a layer (B) covering the core (A) with ruthenium tetroxide; a step (S2) of obtaining a cured product of the composition containing the epoxy resin curing agent that has undergone the step (S1); and A step (S3) of electron staining the slice of the solidified product with osmium tetroxide.

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