Epoxy resin curing agents, their applications, and methods for manufacturing dyed and cured products

Abstract

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

Description

Technical Field

[0001] This invention relates to epoxy resin curing agents, epoxy resin compositions, sealing materials, conductive materials, thermally conductive materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, impregnation and fixing materials, interlayer insulating films, thin-film solder resists, sealing sheets, conductive films, anisotropic conductive films, thermally conductive films, and methods for manufacturing dyed and cured products. Background Technology

[0002] Epoxy resins, in the form of epoxy resin compositions comprising an epoxy resin curing agent, are widely used in electrical and electronic components such as semiconductor packages, camera modules, and as insulating materials, sealing materials, adhesives, conductive materials, matrix resins for fiber-reinforced plastics, impregnation and fixing agents for motor coils, and adhesives for automotive structures.

[0003] In recent years, the epoxy resin composition has been used as a bottom filler material for protecting the circuit surface of the chip and the bump connection in semiconductor packages, a chip bonding film for chip bonding, a film for forming an interlayer insulating layer, a film for forming a solder resist layer, and other film materials.

[0004] As epoxy resin compositions suitable for use as underfill materials, epoxy resin compositions including, for example, microencapsulated curing agents are disclosed (see, for example, Patent Document 1). Additionally, as epoxy resin compositions suitable for use as film materials, epoxy resin compositions including, for example, microencapsulated curing agents are disclosed (see, for example, Patent Document 2).

[0005] Prior art literature

[0006] Patent documents

[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] The problem the invention aims to solve

[0010] Epoxy resin compositions, as described above, can be used for a variety of applications, with the components selected appropriately for each application. Typical alternative composition systems include, for example, epoxy resin compositions containing low-molecular-weight epoxy compounds as reactive diluents for underfill material applications. For film material applications, epoxy resin compositions containing solvents such as methyl ethyl ketone (MEK) and cyclohexanone for preparing varnishes are examples. For dual-curing adhesive applications that cure by both light and heat, epoxy resin compositions containing low-molecular-weight acrylic compounds are examples. As epoxy resin curing agents, there is a need for epoxy resin curing agents capable of imparting both retention stability and reactivity in the various composition systems described above.

[0011] Furthermore, when an epoxy resin composition contains fillers, the cured product obtained by curing the epoxy resin composition needs to have an excellent appearance, that is, an appearance in which the filler is uniformly dispersed in the cured product. In recent years, with the increasing functionalization of electronic materials, there has been a search for achieving a superior appearance in minute areas compared to the past. In other words, filler aggregates and curing agent aggregates that were previously considered small in size are sometimes now regarded as having an appearance problem.

[0012] From the above perspective, 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.

[0013] The object of the present invention is to provide an epoxy resin curing agent, etc., that imparts excellent stability and reactivity to epoxy resin compositions mixed with low molecular weight epoxy compounds, solvents or low molecular weight acrylic compounds, and that imparts excellent appearance even to small areas when curing epoxy resin compositions containing fillers.

[0014] Solutions for solving problems

[0015] Through in-depth research, the inventors discovered that the above-mentioned problems could be solved by using an epoxy resin curing agent with a specified composition, thus completing this invention.

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

[0017] [1] An epoxy resin curing agent, comprising:

[0018] Contains a nitrogen-containing nucleus (A), and

[0019] Layer (B) covering the aforementioned core (A),

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

[0021] [2] According to the epoxy resin curing agent of [1], wherein the core (A) contains 0.001 to 20% by mass of an amine compound (a) with 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 containing tertiary amines.

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

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

[0025] [6] According to the epoxy resin curing agent of [5], wherein the particle size D of the above-mentioned core (A) has a cumulative percentage of 99% under sieve. 99 With the above D 50 The ratio of D 99 / D 50 The number is below 8.

[0026] [7] According to the epoxy resin curing agent described in [5] or [6], wherein the specific surface area value Y (m²) of the core (A) is... 2 / g) multiplied by the above D 50 The value obtained by (μm) is above 3.0 and below 9.0.

[0027] [8] The epoxy resin curing agent according to any one of [5] to [7], wherein the specific surface area value Y (m²) of the core (A) is... 2 / g) multiplied by the above D 50 The value obtained by (μm) is greater than 9.0 and less than 18.0.

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

[0029]

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

[0030]

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

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

[0031]

[0032] (In formula (1), X1 represents an alkylene group with 2 or more but less than 5 carbon atoms that may be selected to have a substituent R. Substituent 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. Here, it may be selected from any of R1 to R5 to form a fused ring compound that constitutes the same ring.)

[0033]

[12] According to the epoxy resin composition of

[11] , 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) comprises 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300, wherein the amine compound (a) comprises 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 any one of the epoxy resin curing agents described in [1] to [8] or any one of the epoxy resin compositions described in [9] to

[14] .

[0037]

[16] A conductive material comprising any one of the epoxy resin curing agents described in [1] to [8] or any one of the epoxy resin compositions described in [9] to

[14] .

[0038]

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

[14] .

[0039]

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

[14] .

[0040]

[19] An adhesive for a camera module comprising any one of the epoxy resin curing agents described in [1] to [8] or any one of the epoxy resin compositions described in [9] to

[14] .

[0041]

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

[14] .

[0042]

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

[14] .

[0043]

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

[14] .

[0044]

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

[14] .

[0045]

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

[14] .

[0046]

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

[14] .

[0047]

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

[14] .

[0048]

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

[14] .

[0049]

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

[14] .

[0050]

[29] A method for manufacturing a dyed and cured material includes the following steps: 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.

[0051] Step (S2) to obtain a cured product comprising the epoxy resin curing agent described in step (S1); and

[0052] The process of electron staining the slices of the above-mentioned cured material with osmium tetroxide (S3).

[0053] The effects of the invention

[0054] According to the present invention, epoxy resin curing agents can be provided that impart excellent stability and reactivity to epoxy resin compositions mixed with low-molecular-weight epoxy compounds, solvents, or low-molecular-weight acrylic compounds, and that impart excellent appearance even to small areas when curing epoxy resin compositions containing fillers. Attached Figure Description

[0055] Figure 1 This is an edited image created by drawing lines at specified locations in order to confirm staining properties in an image obtained by performing image analysis on a TEM observation image of epoxy resin curing agent 1 of Example 1.

[0056] Figure 2 For along Figure 1 The curve is formed by plotting the brightness at various locations using line segments in the image.

[0057] Figure 3 This is an edited image created by drawing lines at specified locations in order to confirm staining properties in an image obtained from the TEM observation image of the epoxy resin curing agent 3 of Example 3, in order to perform image analysis.

[0058] Figure 4 For along Figure 3 The curve is formed by plotting the brightness at various locations using line segments in the image.

[0059] Figure 5 This is an edited image created by drawing lines at specified locations in order to confirm staining properties in an image obtained by performing image analysis on a TEM observation image of epoxy resin curing agent 4 of Example 4.

[0060] Figure 6 For along Figure 5 The curve is formed by plotting the brightness at various locations using line segments in the image.

[0061] Figure 7 This is an edited image created by drawing lines at specified locations in order to confirm staining properties in the image obtained from the TEM observation image of epoxy resin curing agent R-1 of Comparative Example 1, in order to perform image analysis.

[0062] Figure 8 For along Figure 7 The curve is formed by plotting the brightness at various locations using line segments in the image.

[0063] Figure 9 An image showing the appearance evaluation results of a small area in Example 1.

[0064] Figure 10 An image showing the appearance evaluation results of a small area in Comparative Example 1. Detailed Implementation

[0065] The following provides a detailed description of a method for implementing the present invention (hereinafter also referred to as "this embodiment"). This embodiment is illustrative of the invention and is not intended to limit the invention to the following content. The invention can be implemented with appropriate modifications within its scope.

[0066] [Epoxy resin curing agent]

[0067] The epoxy resin curing agent of this embodiment comprises a core (A) containing a nitrogen-containing compound and a layer (B) covering the core (A). When the epoxy resin curing agent is stained with ruthenium tetroxide and osmium tetroxide and observed by a transmission electron microscope (hereinafter also referred to as "TEM") and a brightness curve is obtained by image processing, the interior of the layer (B) contains a region with brightness α, which is higher than the brightness β of the outermost part of the layer (B) and the brightness γ of the boundary between the layer (B) and the core (A) (hereinafter, the presence of the above-mentioned region in the layer (B) is also referred to as "having the desired staining property"). Because the epoxy resin curing agent of this embodiment is configured in the above manner, it can impart excellent stability and reactivity when mixed with low-molecular-weight epoxy compounds, solvents, or low-molecular-weight acrylic compounds to form an epoxy resin composition, and can impart excellent appearance even in small areas when an epoxy resin composition containing fillers is formed and cured.

[0068] In this embodiment, it is sufficient for at least a portion of the epoxy resin curing agent to have the desired dyeability, and the more areas with the desired dyeability, the more preferred. Furthermore, it is particularly preferred that the entire area of ​​the epoxy resin curing agent has the desired dyeability.

[0069] (Staining methods and TEM observation)

[0070] The following describes the dyeing method and observation method after dyeing using the epoxy resin curing agent of this embodiment. First, 10.6 mL of the main agent (Quetol 812, manufactured by Nisshin EM Co., Ltd.), 9.4 mL of the curing agent (methylnadic anhydride: MNA, manufactured by Nisshin EM Co., Ltd.), and 0.34 mL of the reaction promoter (2,4,6-tris(dimethylaminomethyl)phenol, manufactured by Nisshin EM Co., Ltd.: DMP-30) are mixed and stirred with a stirrer for 15 minutes. After removing air bubbles, the mixture is degassed under vacuum to obtain the epoxy resin composition for dyeing. Next, the epoxy resin curing agent of this embodiment was subjected to electron staining by coexisting with ruthenium tetroxide in a sealed and light-proof container at room temperature and atmospheric pressure for 10 minutes. Afterward, it was mixed with the aforementioned epoxy resin composition for staining and cured at 40°C for 42 hours. The cured product containing the epoxy resin curing agent was then sliced ​​into 80 nm sections using an ultramicrotome. These sections were then coexisted 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 was then irradiated with an electron beam using a TEM, the focus adjusted to align with the sample, and observed at an accelerating voltage of 120 kV and a magnification of 30,000x to obtain a TEM image. These operations can be performed in more detail based on the methods described in the following embodiments.

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

[0072] The obtained TEM observation image is read using the image analysis software ImageJ. After applying a mid-range filter (Radius 2.0 pixels), a line segment is drawn from the outermost layer (B) in a manner that includes the boundary between the kernel (A) and layer (B). A brightness curve is formed along this line segment. These operations can be implemented in more detail based on the methods described in the embodiments described later.

[0073] [A nucleus containing nitrogen-containing compounds]

[0074] The core (A) containing a nitrogen-containing compound is a particle or group of particles containing a nitrogen-containing compound (hereinafter, these are also collectively referred to as "core (A) particles"). There is no particular limitation on the nitrogen-containing compound, but examples 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. One or more of these can be used.

[0075] As low-molecular-weight amine compounds, including but not limited to the following, examples include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diaminodiphenylmethane, diaminodiphenyl sulfone, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperidine, piperidinone, diphenylamine, phenylmethylamine, phenylethylamine, and other compounds that do not possess tertiary amine properties; 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; imidazoles, 2-methylimidazolium, 4-methylimidazolium, 2-ethyl-4-methylimidazolium, 2-undecylimidazolium, 2-heptadecanylimidazolium, 2-phenylimidazolium, 1-aminoethyl-2-methylimidazolium, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazolium, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazolium, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazolium, 1-(2-hydroxy- Imidazole derivatives such as 3-butoxypropyl)-2-ethyl-4-methylimidazoline; 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]octane.2] Octane-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 azines, 2-dimethylaminopyridine, and 4-dimethylaminopyridine; aminothiols such as 2-dimethylaminoethanethiol, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptopyridine, and 4-mercaptopyridine; aminocarboxylic acids such as N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, and pyridinecarboxylic acid; and aminoacylhydrazides such as N,N-dimethylglycine hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide. These can be used alone or in combination of two or more.

[0076] As amine adduct compounds, examples 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 aforementioned low-molecular-weight amine compounds. In this embodiment, the amine adduct compound preferably includes an imidazole-based amine adduct compound. The imidazole-based amine adduct can be a reaction product of imidazoles with, for example, any one or more of carboxylic acid compounds, sulfonic acid compounds, urea compounds, isocyanate compounds, and epoxy resins. From the viewpoint of layer (B) formation, it is preferable that the imidazole-based amine adduct compound includes a reaction product of imidazoles and epoxy resins; from the viewpoint of mechanical strength, it is particularly preferable that the imidazole-based amine adduct compound includes a reaction product of imidazoles and bisphenol-type epoxy resins.

[0077] As carboxylic acid compounds, examples include, but are not limited to, succinic acid, adipic acid, sebacic acid, phthalic acid, dimer acids, etc.

[0078] As sulfonic acid compounds, examples include, but are not limited to, ethanesulfonic acid and p-toluenesulfonic acid.

[0079] Urea compounds, including but not limited to the following, include urea, methylurea, dimethylurea, ethylurea, tert-butylurea, etc.

[0080] As isocyanate compounds, examples include, but are not limited to, aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, aliphatic triisocyanates, and polyisocyanates.

[0081] As aliphatic diisocyanates, examples include, but are not limited to, ethylene diisocyanate, propylene diisocyanate, butyl diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, etc.

[0082] Alicyclic diisocyanates, including but not limited to the following, include isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanate-cyclohexane, 1,3-bis(isocyanate-methyl)-cyclohexane, 1,3-bis(2-isocyanate-propyl-2-yl)-cyclohexane, etc.

[0083] As aromatic diisocyanates, examples include, but are not limited to, toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, etc.

[0084] As aliphatic triisocyanates, examples include, but are not limited to, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, 1,3,6-triisocyanate methyl hexane, etc.

[0085] Examples of polyisocyanates include, but are not limited to, polymethylene polyphenyl polyisocyanates and polyisocyanates derived from the above-mentioned diisocyanate compounds. Examples of polyisocyanates derived from the above-mentioned diisocyanate compounds include isocyanurate-type polyisocyanates, biuret-type polyisocyanates, carbamate-type polyisocyanates, urethane-type polyisocyanates, and carbodiimide-type polyisocyanates.

[0086] As epoxy resins, examples include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol M type epoxy resins, bisphenol P type epoxy resins, tetrabromobisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, tetrabromobiphenyl type epoxy resins, diphenyl ether type epoxy resins, benzophenone type epoxy resins, phenylbenzoate type epoxy resins, diphenyl sulfide type epoxy resins, diphenyl sulfoxide type epoxy resins, diphenyl sulfone type epoxy resins, diphenyl disulfide type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, hydroquinone type epoxy resins, methyl hydroquinone type epoxy resins, dibutyl hydroquinone type epoxy resins, resorcinol type epoxy resins, methyl resorcinol type epoxy resins, catechol type epoxy resins, and other difunctional epoxy resins; N,N- Trifunctional epoxy resins such as diglycidylaminobenzene type epoxy resin and triazine type epoxy resin; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane type epoxy resin and diaminobenzene type epoxy resin; polyfunctional epoxy resins such as phenol-phenolic varnish type epoxy resin, cresol-phenolic varnish type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, naphthol aralkyl type epoxy resin, and brominated phenol-phenolic varnish type epoxy resin; monoepoxides 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 in one type or in combination of two or more types.

[0087] Examples of amide compounds include, but are not limited to, dicyandiamide and its derivatives, compounds formed by the addition of anhydrides to amine compounds, and hydrazide compounds.

[0088] As acylhydrazide compounds, examples include, but are not limited to, succinic acid dihydrazide, adipic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, p-oxybenzoic acid dihydrazide, salicylic acid dihydrazide, phenylaminopropionic acid dihydrazide, maleic acid dihydrazide, etc.

[0089] As guanidine compounds, examples include, but are not limited to, dicyandiamide, methylguanidine, ethylguanidine, propylguanidine, butylguanidine, dimethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, toluene-methylguanidine, etc. One or more of these compounds may be used.

[0090] Among these nitrogen-containing compounds, from the viewpoint of balancing reactivity during thermosetting and storage stability when preparing epoxy resin compositions, 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 a low-molecular-weight amine compound, it is preferable to include an amine compound (a) with a molecular weight of 50 to 300. That is, from the viewpoint of suppressing thickening caused by the reaction between the core (A) and the epoxy resin penetrating the layer (B) during the preparation of the epoxy resin composition, a molecular weight of 50 or more is preferred, a molecular weight of 60 or more is more preferred, and a molecular weight of 70 or more is even more preferred. In addition, from the viewpoint of exhibiting high reactivity based on excellent diffusion ability, a molecular weight of 300 or less is preferred, a molecular weight of 270 or less is more preferred, and a molecular weight of 240 or less is even more preferred.

[0092] As for the amine compound (a), from the viewpoint of excellent reactivity with epoxy resin, imidazoles, aliphatic amine compounds, and cyclic amine compounds containing tertiary amines are preferred. Among imidazole compounds, imidazole, 2-methylimidazolium, 4-methylimidazolium, 2-ethyl-4-methylimidazolium, 2-undecylimidazolium, and 2-phenylimidazolium are more preferred. Among aliphatic amine compounds, ethylenediamine, propylenediamine, hexamethylenediamine, and diethylenetriamine are more preferred. Triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophorone diamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, and piperidine are preferred as cyclic amine compounds containing tertiary amines, and more preferably 1,4-diazabicyclo[2.2.2]octane, 1-diazabicyclo[2.2.2]octane-3-one, 1,8-diazabicyclo(5,4,0)-undecene-7, and 1,5-diazabicyclo(4,3,0)-nonene-5.

[0093] Regarding the content of low-molecular-weight amine compounds in the core (A), from the viewpoint of balancing reactivity during thermosetting and stability during storage when preparing the epoxy resin composition, the content 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, even more preferably 0.008% by mass or more and 14% by mass or less, and particularly preferably 0.01% by mass or more and 12% by mass or less. From the same viewpoint, the content of 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, even more preferably 0.008% by mass or more and 14% by mass or less, and particularly preferably 0.01% by mass or more and 12% by mass or less, in the total mass of the core (A).

[0094] From the viewpoint of mechanical strength, the amine adduct system 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 strength and toughness, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferred. As the low-molecular-weight amine compound, from the viewpoint of imparting excellent reactivity to the epoxy resin to the obtained amine adduct system compound, among the aforementioned low-molecular-weight amine compounds, imidazole compounds, compounds having at least one primary amino group and / or secondary amino group but not 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 an 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 aforementioned low molecular weight amine compound to obtain an amine adduct system compound.

[0096] The core (A) may also contain components other than nitrogen-containing compounds, including, but not limited to, phenolic curing agents, acid anhydride curing agents, catalyst-type curing agents, etc.

[0097] Phenolic curing agents include, but are not limited to, phenolic varnish resins, cresol varnish resins, phenol aralkyl resins, cresol aralkyl resins, naphthol aralkyl resins, biphenyl-modified phenolic resins, biphenyl-modified phenol aralkyl resins, dicyclopentadiene-modified phenolic resins, aminotriazine-modified phenolic resins, naphthol varnish resins, naphthol-phenol co-condensed phenolic varnish resins, naphthol-cresol co-condensed phenolic varnish resins, allyl acrylic phenolic resins, etc.

[0098] As an anhydride-based curing agent, examples 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] As a catalyst-type curing agent, examples include, but are not limited to, cationic thermosetting catalysts and BF3-amine complexes.

[0100] From the viewpoint of preservation stability, it is preferable that the core (A) is solid at 25°C and 1013 hPa. Therefore, when the epoxy resin composition is obtained by mixing with other components, even if the layer (B) is scratched, the components of the core (A) are inhibited from dissolving into the layer (B), thus tending to maintain preservation stability.

[0101] The particle size D with a cumulative undersize percentage of 50% for nucleus (A) 50 Preferably, it is larger than 0.3 μm and smaller than 12 μm. This is achieved by making the D of the nucleus (A)... 50 A depth greater than 0.3 μm further prevents the cores from aggregating, making the formation of the layer (B) easier and further improving the storage stability when preparing epoxy resin compositions. This is achieved by increasing the D-value of the core (A). 50 With a particle size of 12 μm or less, when obtaining the desired epoxy resin composition, it can prevent the formation of large-particle aggregates when compounding diluents, fillers, pigments, dyes, flow modifiers, thickeners, reinforcing agents, release agents, wetting agents, stabilizers, flame retardants, surfactants, organic solvents, conductive microparticles, crystalline alcohols, and other resins, and tends to ensure sufficient long-term reliability of the cured product. Regarding the core (A) D 50 As a lower limit, it is preferably greater than 0.3 μm, more preferably greater than 0.4 μm, and even more preferably greater than 0.5 μm. As an upper limit, it is preferably less than 12 μm, more preferably less than 10 μm, and even more preferably less than 9 μm.

[0102] The D of nucleus (A) 50 This refers to the average particle size defined by the median particle size. More specifically, it refers to the Stockwell particle size measured using a particle size analyzer (Horiba Seisakusho, "HORIBA LA-920") and the laser diffraction / light scattering method.

[0103] As the core (A) of D 50 Methods for controlling the values ​​to the above range are not limited to the following methods, and examples include: methods for precise control in the crushing process of bulk core materials; and methods that, as the crushing process of bulk core materials, include coarse crushing and fine crushing processes, and further use a precision grading device to grade the desired D values. 50Methods for obtaining materials with specific particle sizes; methods for spray drying solutions obtained by dissolving bulk core materials in solvents, etc.

[0104] As for the equipment used in pulverization, various types can be employed, such as ball mills, grinding mills, bead mills, and jet mills, with impact pulverization equipment being preferred. Examples of such impact pulverization equipment include rotary jet mills and reverse jet mills. Jet mills utilize a high-speed jet stream, such as air, to atomize solid materials by impacting each other. Methods for precise control during the pulverization process include controlling the temperature, humidity, and the amount of material pulverized per unit time. After the pulverization process, a precise classifying device is used to classify the material, aiming for a specific particle size distribution. 50 Methods for obtaining substances, such as: obtaining a specified D by classification after pulverization. 50 Methods for classifying powders and granules include using sieves (e.g., standard sieves such as 325 mesh, 250 mesh, etc.) and classifiers; and classifying by air force based on particle specific gravity. Examples of classifiers include wet classifiers and dry classifiers, with dry classifiers being generally preferred. Examples of such classifiers include, but are not limited to, the "Elbow-Jet" manufactured by Nippon 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 Saishin Enterprise Co., Ltd., the "DONASELEC" manufactured by DONALDSON Co., Ltd., the "YM Microcassette" manufactured by Yaskawa Corporation, the "TurboClassifier" manufactured by Nisshin Engineering Co., Ltd., and various other gas separators, micron separators, MICROPLEX, ACCU-CUT, and other dry classification devices.

[0105] As a method for granulating the particles constituting the core directly without pulverizing, a method of spray drying a solution obtained by dissolving the bulk core material in a solvent can be cited. Specifically, a method can be cited that involves uniformly dissolving the core material in a suitable organic solvent, spraying it in the form of tiny droplets in a solution state, and then drying it with hot air or the like. A typical spray drying apparatus can be cited as the drying apparatus in this case.

[0106] Another method for granulating the core particles is as follows: the core material is uniformly dissolved in a suitable organic solvent, and then a poor solvent containing a nitrogen-containing compound constituting the core (A) is added while the uniform solution is vigorously stirred, thereby causing the core (A) to precipitate in the form of small particles. Then, the precipitated particles are filtered and separated, and dried at a low temperature below the melting point of the core (A) to remove the solvent.

[0107] D, as the nucleus (A) whose particle-forming state is adjusted through methods other than hierarchical processes, is... 50 Methods, such as those using D, can be listed as examples. 50 Different types of particles are mixed to adjust D 50 Methods, etc. For example, in the case of large-particle-size nuclei (A) that are difficult to crush and classify, D can be produced by adding other small-particle-size nuclei (A) and mixing them. 50 Curing agents falling within the above-mentioned range.

[0108] The curing agent obtained by this operation can be further graded as needed. Examples of mixers used for mixing such powders include: a container rotary mixer that rotates the container containing the powder to be mixed; a container stationary mixer that mixes the powder by means of mechanical stirring or airflow stirring without rotating the container; and a composite mixer that mixes the powder by rotating the container and using other external forces.

[0109] Regarding the nucleus (A), from the perspective of preventing particles from agglomerating, a particle size D with a cumulative percentage of 99% passing through the sieve is used. 99 Compared to D 50 The ratio (hereinafter sometimes simply referred to as "D") 99 / D 50 The particle size distribution indicated 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 With a value below 8.0, the core (A) powder particles have fewer coarse particles and tend to inhibit the formation of aggregates and prevent damage to the physical properties of the cured product obtained during the curing of epoxy resin compositions.

[0111] D 99 / D 50 The smaller the value, the sharper the particle size distribution of the core (A), and the easier it is to obtain a homogeneous cured product and good curing performance when making epoxy resin compositions.

[0112] D 99 / D 50Preferably, it should be 1.0 or higher. By making D... 99 / D 50 A value above 1.0 indicates a tendency to suppress the formation of more gaps between nuclei (A) particles. D 99 / D 50 More preferably, it is 1.2 or higher; more preferably, it is 1.5 or higher; more preferably, it is 1.7 or higher; and especially preferably, it is 2.0 or higher.

[0113] Particle size D with a cumulative percentage of 99% passing through the sieve 99 This refers to the average particle size defined by the median particle size. More specifically, it refers to the Stockwell particle size measured using a particle size analyzer (Horiba Seisakusho, "HORIBA LA-920") and the laser diffraction / light scattering method.

[0114] As the core (A) of D 99 / D 50 Methods for controlling the values ​​within the above range can be listed for controlling D. 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 (m²) of the core (A) 2 / g) multiplied by the above particle size D, which represents a cumulative percentage of 50% under sieve. 50 The value obtained from (μm) can be above 3.0 and below 9.0.

[0116] When the value is 3.0 or higher, there is a tendency to suppress the aggregation of nucleus (A) particles; when the value is 9.0 or lower, there is a tendency for the formation of layer (B) to become easier.

[0117] From the viewpoint of inhibiting the aggregation of nucleus (A) particles, the above value can be 3.5 or higher, or 4.0 or higher. From the viewpoint of facilitating the formation of layer (B), the above value can be 8.6 or lower, or 8.3 or lower.

[0118] The specific surface area Y (m²) of the core (A) 2 / g) can be determined based on the methods described in the examples.

[0119] In one embodiment, the specific surface area value Y (m²) of the core (A) 2 / g) multiplied by particle size D 50 The value obtained from (μm) can exceed 9.0 and be below 18.0. When the value exceeds 9.0, there is a tendency to increase reactivity, and when the value is below 18.0, there is a tendency to form a layer (B) with sufficient stability. From this point of view, the value can be set to 17.0 or below, or 16.5 or below.

[0120] The specific surface area value Y (m²) was adjusted within the range of 3.0 to 18.0. 2 / g) multiplied by particle size D 50 The method for obtaining the value of (μm) can be exemplified by adjusting the control D mentioned above. 50 The method involves conditions and conditions for modifying the surface of the core (A). Examples of surface modification include mechanically rounding the particles or hot air treatment; in these cases, the aforementioned value tends to decrease. However, by appropriately setting the aforementioned pulverizing device, pulverizing conditions, grading device, and grading conditions, the aforementioned value can be increased.

[0121] [Layer (B)]

[0122] As for layer (B), there are no particular limitations as long as it has the desired dyeability, and examples include layers containing synthetic resins or inorganic oxides. Among these, from the viewpoint of stability during storage and susceptibility to damage during heating, layers containing synthetic resins are preferred.

[0123] The synthetic resin used in layer (B) is not limited to the following, but may include, for example, 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) with its destructive properties upon heating.

[0124] The epoxy resin used in layer (B) is not limited to the following, and examples include epoxy resins having two or more epoxy groups, resins generated by reacting epoxy resins having two or more epoxy groups with compounds having two or more active hydrogen atoms, and reaction products of compounds having two or more epoxy groups with compounds having one active hydrogen atom and a carbon-carbon double bond. From the viewpoint of stability, resins generated by reacting compounds having two or more epoxy groups with compounds having two or more active hydrogen atoms are preferred, and reaction products of amine curing agents and epoxy resins having two or more epoxy groups are particularly more preferred. Examples of epoxy resins include the aforementioned epoxy resins, and examples of amine curing agents include nitrogen-containing compounds used in core (A).

[0125] Phenolic resins include, but are not limited to, phenol-formaldehyde condensates, cresol-formaldehyde condensates, resorcinol-formaldehyde condensates, bisphenol A-formaldehyde condensates, and polyethylene polyamine-modified phenol-formaldehyde condensates.

[0126] As a polyester resin, examples include, but are not limited to, ethylene glycol-terephthalic acid-polypropylene glycol condensate, ethylene glycol-butanediol-terephthalic acid condensate, and terephthalic acid-ethylene glycol-polyethylene glycol condensate.

[0127] As a polyethylene-based resin, examples include, but are not limited to, ethylene-propylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, and ethylene-vinyl acetate-acrylic acid copolymer.

[0128] As for nylon-based resins, examples include, but are not limited to, adipic acid-hexamethylenediamine condensate, sebacic acid-hexamethylenediamine condensate, and p-phenylenediamine-terephthalic acid condensate.

[0129] As polystyrene-based resins, examples include, but are not limited to, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, acrylonitrile-styrene-divinylbenzene copolymers, and styrene-acrylic alcohol copolymers.

[0130] As a urethane resin, examples include, but are not limited to, butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, toluene diisocyanate, diphenylmethane diisocyanate, phenylenediamine diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, bitoluidine diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and other isocyanate monomers, or their condensates, or polymers thereof with monohydric alcohols or polyhydric alcohols. Among these, urethane resins are preferably addition polymers of monohydric alcohols or polyhydric alcohols with monoisocyanates or polyisocyanates.

[0131] As inorganic oxides, examples include boron compounds such as boron oxide and boron esters; silicon dioxide; and calcium oxide. Among these, boron oxide is preferred from the viewpoint of the stability of the membrane constituting the shell and its susceptibility to damage upon heating.

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

[0133] As isocyanate compounds, nitrogen-containing compounds and epoxy resins, the compounds described above regarding the nucleus (A) can be used.

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

[0135] As a compound having at least one primary amino group and / or secondary amino group, examples include, but are not limited to, aliphatic amines, alicyclic amines, aromatic amines, etc.

[0136] Aliphatic amines include, but are not limited to, alkylamines such as methylamine, ethylamine, propylamine, butylamine, and dibutylamine; alkylene diamines such as ethylenediamine, propylenediamine, butylenediamine, and hexamethylenediamine; polyalkylene polyamines such as diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; and polyoxyalkylene polyamines such as polyoxypropylenediamine and polyoxyethylenediamine.

[0137] As alicyclic amines, examples include, but are not limited to, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, and isophorone diamine.

[0138] Aromatic amines include, but are not limited to, aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, diaminodiphenyl sulfone, etc.

[0139] Examples of compounds having at least one hydroxyl group include alcohols and phenols.

[0140] As alcohol compounds, not limited to the following substances, examples include monohydric alcohols such as methanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, stearyl alcohol, eicosanool, allyl alcohol, crotonol, propargyl alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc.; 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, pentaerythritol, etc.; and 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, carboxyl, primary amino, secondary amino, or thiol group.

[0141] These alcohol compounds can be any of the primary, secondary, or tertiary alcohols.

[0142] 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, 2-(dimethylaminomethyl)phenol, and 2,4,6-tris(dimethylaminomethyl)phenol.

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

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

[0145] Regarding the mixing ratio of isocyanate compound and active hydrogen compound used to prepare the reaction product contained in layer (B), it is preferably in the range of 1:0.1 to 1:1000, calculated as (isocyanate group in isocyanate compound): (active hydrogen in active hydrogen compound) (equivalent ratio).

[0146] The above reactions can be carried out in a specified dispersion medium as needed.

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

[0148] As solvents, examples include, but are not limited to, hydrocarbons such as benzene, toluene, xylene, cyclohexane, mineral oil, 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] As plasticizers, examples include, but are not limited to, dibutyl phthalate, di(2-ethylhexyl) phthalate and other phthalate-based plasticizers; di(2-ethylhexyl) adipate and other aliphatic diester-based plasticizers; tricresyl phosphate and other triphosphate-based plasticizers; polyethylene glycol esters and other glycol-based plasticizers.

[0150] As a type of resin, it is not limited to the following, but can include, for example, silicone resins, epoxy resins, phenolic resins, etc.

[0151] These can be used in one type or in combination of two or more types.

[0152] In the above-mentioned process, the reaction between epoxy resin and nitrogen-containing compound is typically 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, and more preferably 2 hours to 72 hours. Furthermore, solvents and plasticizers are preferred as dispersion media.

[0153] It should be noted that the above reaction product, in terms of the mass percentage as a result of its presence in layer (B), is typically 1% by mass or more, preferably 50% by mass or more, and can be 100% by mass.

[0154] Methods for forming layer (B) include, for example, the following methods (1) to (3).

[0155] (1): A method for reducing the solubility of the core (A) particles and the material forming the layer (B) in the dispersion medium after dissolving / dispersing the core (A) particles and the material forming the layer (B) in the solvent as the dispersion medium, so as to precipitate the layer (B) forming material on the surface of the core (A) particles.

[0156] (2): A method of dispersing core (A) particles in a dispersion medium, adding the above-mentioned layer (B) forming material to the dispersion medium, and precipitating it on the core (A) particles.

[0157] (3): A method of adding a layer (B) forming material to a dispersion medium, wherein the layer (B) is generated on the surface of the core (A) particle as a reaction field.

[0158] Here, the methods (2) and (3) above can simultaneously carry out the reaction and coverage, and are therefore preferred.

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

[0160] There is no particular limitation on the method for separating the epoxy resin curing agent from the dispersion medium after forming layer (B) by the methods described in (2) and (3) above. For example, a method can be listed that removes the dispersion medium and unreacted raw materials of the forming layer (B) by filtration.

[0161] After removing the dispersion medium, it is preferable to clean the epoxy resin curing agent.

[0162] There are no particular limitations on the cleaning method; the residue can be cleaned using a solvent that does not dissolve the residue during the separation process via filtration.

[0163] Epoxy resin curing agent can be obtained in powder form by filtering, washing, and then drying. The drying method is not particularly limited, but drying at a temperature below the melting or softening point of the core (A) and layer (B) is preferred; examples include vacuum drying. By preparing it as a powder, the epoxy resin curing agent and epoxy resin can be easily mixed. Furthermore, when using epoxy resin as a dispersion medium, an epoxy resin composition that is integral with the epoxy resin while forming layer (B) is obtained, which is therefore advantageous.

[0164] The formation reaction of layer (B) is carried out within a temperature range of -10°C to 150°C, preferably 0°C to 100°C, for 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 left to stand in an environment below 5°C for at least 8 hours (after a standing process). After the standing process, layer (B) tends to have the desired staining properties. It should be noted that in the standing process of this embodiment, it is preferable that the temperature difference between the measured temperature and the set temperature is low; for example, it is preferable that the lowest temperature T from the start time t1 to the end time t2 of the standing process is low. L With the highest temperature T H The temperature difference is less than 4°C. Under these conditions, it is easier to obtain a layer (B) with the desired staining properties.

[0165] It should be noted that, as described above, the formation reaction can be carried out using a dispersion medium, and this dispersion medium can be removed between the formation reaction and the settling step. Furthermore, the set temperature in the settling step can be lower than the temperature of the formation reaction. For example, the set temperature in the settling step can be set at least 40°C lower than the reaction temperature in the formation reaction, or at least 45°C lower. Moreover, the formation reaction and the settling step can be carried out in the same system or in different systems.

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

[0167] The thickness of layer (B) is preferably 1 nm to 1000 nm, more preferably 2 nm to 800 nm, even more preferably 3 nm to 600 nm, and even more preferably 4 nm to 400 nm. Making the thickness of layer (B) 1 nm or more tends to impart sufficient stability. Furthermore, making the thickness of layer (B) 1000 nm or less tends to impart sufficient reactivity.

[0168] Here, the thickness of layer (B) refers to the distance between any point on the boundary of brightness γ, which corresponds to the boundary between layer (B) and core (A), and the point where the shortest line segment connecting that point to the point of brightness β, which corresponds to the outermost brightness of layer (B), is found. Furthermore, the thickness of layer (B) can vary depending on its location. In this case, the thickness 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 even more preferably in the range of 4 nm to 400 nm.

[0169] [Staining properties of layer (B)]

[0170] For the epoxy resin curing agent of this embodiment, when stained with ruthenium tetroxide and osmium tetroxide and observed by TEM, and a brightness curve is obtained by image processing, the interior of the aforementioned layer (B) contains a region with brightness α, which is higher than the brightness β of the outermost part of the aforementioned layer (B) and the brightness γ of the boundary between the aforementioned layer (B) and the aforementioned core (A). The presence of the aforementioned region inside the layer (B) can be confirmed based on the method described in the embodiments described later.

[0171] It should be noted that when the epoxy resin curing agent is the masterbatch type epoxy resin curing agent composition described later, the epoxy resin and curing agent components can be separated by a centrifuge after the dispersion medium is added, and then the curing agent components are collected and dried to obtain a separate epoxy resin curing agent.

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

[0173] In this specification, when a layer with different staining properties exists between the area of ​​the epoxy resin composition for staining and the core (A) in the TEM observation described above, it is referred to as layer (B). Differences in staining properties can be confirmed by visually examining the TEM image. Furthermore, differences in staining properties can be confirmed by observing the non-monotonicity of the brightness from the area of ​​the epoxy resin composition for staining to the core (A) in the brightness curve diagram described above.

[0174] Layer (B) can be a single layer or multiple layers.

[0175] In this specification, the outermost layer (B) is defined as the location with the lowest brightness near the boundary between layer (B) and the area of ​​the epoxy resin composition for dyeing, and the boundary between the core (A) and layer (B) is defined as the location with the lowest brightness near the boundary between the core (A) and layer (B). When layer (B) is multilayered, it is sufficient for at least one layer (B) to have the desired dyeability, and preferably all layers (B) have the desired dyeability.

[0176] The sphericity of the epoxy resin curing agent in this embodiment can be 0.90 or higher, 0.93 or higher, 0.95 or higher, or 0.98 or higher. Circularity indicates the degree of approximation to a sphere, with a sphere having a sphericity of 1. Furthermore, the surface of this epoxy resin curing agent (the surface of layer (B)) can be smooth or uneven. When the surface of layer (B) is smooth, TEM image analysis shows that at the boundary between layer (B) and the area of ​​the dyeing epoxy resin composition, an image that appears to be straight or curved can be observed (see below). Figure 1 , 3On the other hand, when unevenness is observed on the surface of layer (B), the result of TEM image analysis is that the boundary between layer (B) and the area of ​​the dyeing epoxy resin composition can be observed to appear as a wavy or wrinkled pattern (see below). Figure 5 ).

[0177] Additionally, this embodiment may also include: (described later) Figure 2 The case where the brightness of the brightest position in layer (B) is higher than the maximum brightness of the kernel (A), as described later. Figure 4 The case where the brightness of the brightest position in layer (B) is lower than the maximum brightness of the core (A). In either case, a brightness α that is higher than both brightness β and brightness γ is preferred.

[0178] The inventors conducted in-depth research and found that by subjecting the epoxy resin curing agent to the above-described standing process after the formation reaction of layer (B), an epoxy resin curing agent of this embodiment (hereinafter also referred to as a low-staining epoxy resin curing agent) can be obtained, which has a region in the interior of layer (B) with a significantly reduced stainability using ruthenium tetroxide and osmium tetroxide based on the above-described staining method.

[0179] This low-staining epoxy resin curing agent maintains reactivity and exhibits improved resistance to low-molecular-weight epoxy resin compounds, solvents, and low-molecular-weight acrylic resins compared to epoxy resin curing agents with a coating layer that can be easily stained by ruthenium tetroxide or osmium tetroxide (hereinafter also referred to as a high-staining epoxy resin curing agent). It also imparts excellent storage stability when applied to epoxy resin compositions containing these compounds.

[0180] Furthermore, when a filler-containing epoxy resin composition was prepared using a low-staining epoxy resin curing agent and cured, the appearance of the cured product in a small area was observed. The result was that the cured product had a more uniform dispersion of filler and a superior appearance compared to a high-staining epoxy resin curing agent.

[0181] Regarding the mechanism by which the low-staining epoxy resin curing agent of this embodiment maintains reactivity and improves tolerance to low-molecular-weight epoxy compounds, solvents, and low-molecular-weight acrylic compounds, although not intended to be limiting, the following is speculative.

[0182] Due to its high crosslinking density, layer (B) of the low-staining epoxy resin exhibits low staining properties, making it difficult for ruthenium tetroxide and osmium tetroxide to penetrate into the interior of the layer during staining. In other words, by maintaining a high density of crosslinking points and molecular chains, the penetration of low-molecular-weight epoxy compounds, solvents, and low-molecular-weight acrylic compounds into layer (B) is inhibited, preventing these low-molecular-weight compounds from dissolving the core (A), thus demonstrating excellent storage stability. Furthermore, the effect on strength increase within the high-temperature range during the reaction is minimal, thus maintaining reactivity.

[0183] Regarding the mechanism by which the low-staining epoxy resin curing agent of this embodiment is used to prepare an epoxy resin composition containing fillers, and when the appearance of the cured product in a small area is observed after curing, the fillers are more uniformly dispersed, resulting in a cured product with an excellent appearance, although not intended to be limiting, the following is speculation.

[0184] In the low-staining epoxy resin curing agent, the crosslinking points and molecular chains in layer (B) exist in a high-density state, resulting in high surface hardness. Consequently, the contact area during compounding and collision with fillers is small, reducing the probability of curing agent and filler aggregation, and maintaining the uniform dispersion of fillers until the cured stage.

[0185] As described above, when evaluating the stainability of the epoxy resin curing agent of this embodiment, a stained cured product is obtained. Specifically, the method for manufacturing the stained cured product of this embodiment includes the following steps: a step (S1) of electron-staining 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 containing a composition of the epoxy resin curing agent that has undergone the above step (S1); and a step (S3) of electron-staining a slice of the cured product with osmium tetroxide. The epoxy resin curing agent in step (S1) corresponds to the epoxy resin curing agent of this embodiment. Steps (S2) and (S3) can be performed in the same manner as the method for evaluating the stainability of the layer (B) described above. By subjecting the stained cured product to the above-described TEM observation and image processing, it can typically be confirmed that the interior of the layer (B) has regions with higher brightness than the outermost brightness and the brightness of the aforementioned boundaries.

[0186] [Epoxy Resin Composition]

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

[0188] [Epoxy Resin (C)]

[0189] The epoxy resin described above can be used as epoxy resin (C). One type of epoxy resin (C) or two or more types can be used in combination.

[0190] Regarding the mass ratio of epoxy resin curing agent to epoxy resin (C) in this embodiment (epoxy resin curing agent: epoxy resin), from the viewpoint of imparting sufficient reactivity and inhibiting the aggregation of 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. Furthermore, 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 to the curing agent and inhibiting the aggregation of the curing agents, the mass ratio of epoxy resin curing agent to epoxy resin (C) in this embodiment (epoxy resin curing agent: epoxy resin) is preferably 0.1:100 to 1000:100, more preferably 1:100 to 500:100, further preferably 5:100 to 300:100, even more preferably 10:100 to 200:100, and particularly preferably 20:100 to 150:100.

[0191] From the viewpoint of processability and heat resistance, the epoxy resin (C) in the epoxy resin composition of this embodiment preferably includes a bisphenol type epoxy resin, and from the viewpoint of imparting sufficient mechanical properties, it is even more preferable to include any one or more of bisphenol A type epoxy resin and bisphenol F type epoxy resin.

[0192] Regarding the total chlorine content in the epoxy resin (C), from the viewpoint of obtaining an epoxy resin composition with excellent electrical properties and a good balance between curing properties and storage stability, it is preferably 2500 ppm or less, more preferably 2000 ppm or less, even more preferably 1500 ppm or less, and particularly preferably 900 ppm or less.

[0193] Furthermore, from the viewpoint of achieving the specified technical significance, (A) the total chlorine content contained in the epoxy resin is preferably 0.01 ppm or more, more preferably 0.05 ppm or more, even more preferably 0.1 ppm or more, and particularly preferably 0.5 ppm or more.

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

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

[0196] The epoxy resin (C) was washed with xylene, and the washing and filtration were repeated until no epoxy resin was found in the xylene used as the washing solution. Then, the filtrate was distilled off under reduced pressure below 100°C to obtain the epoxy resin. 1–10 g of the obtained epoxy resin sample was accurately weighed to prepare a titration volume of 3–7 mL, dissolved in 25 mL of ethylene glycol monobutyl ether, and 25 mL of a propylene glycol solution containing 1 equivalent of KOH was added. After boiling for 20 minutes, the solution was titrated with an aqueous solution of silver nitrate. The titration volume can be used to calculate the final value.

[0197] Here, among all 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, even more preferably 0.01 ppm or more and 20 ppm or less, and even more 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 that the epoxy resin composition of this embodiment has both high curability and storage stability, and there is a tendency for the cured epoxy resin composition of this embodiment to exhibit excellent electrical properties.

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

[0199] Dissolve 3g of the sample in 50mL of toluene, add 20mL of methanol solution containing 0.1 equivalent of KOH, boil for 15 minutes, and then titrate with silver nitrate aqueous solution. The titration amount can be used for calculation.

[0200] [The alcohol compound (D) shown in formula (1)]

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

[0202] By including component (D), the epoxy resin composition of this embodiment tends to maintain storage stability and improve low-temperature curing properties.

[0203]

[0204] In formula (1), X1 represents an alkylene group having 2 or more but less than 5 carbon atoms, optionally having a substituent R. Substituent 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. Here, it is optionally a fused ring compound formed by any of R1 to R5 forming the same ring. As a substituent containing a heteroatom, for example, it can be a substituent containing a halogen atom.

[0205] Examples of alcohol compounds represented by formula (1) above, not limited to the following, include 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, bisphenol A (2,3-dihydroxypropyl) glycidyl ether, with bisphenol A (2,3-dihydroxypropyl) glycidyl ether being particularly preferred. One or more of these compounds may be used.

[0206] Regarding the amount of component (D) added, from the viewpoint of fully utilizing its reactivity-enhancing effect when added to the epoxy resin composition of this embodiment, it is preferably 0.0001% by mass or more, 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, relative to the total epoxy resin composition. Furthermore, from the viewpoint of suppressing the deterioration 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 even more preferably 2% by mass or less.

[0207] Component (D) can be added when mixed with other components, or it can be generated in the system after mixing, or it can 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 this embodiment may, as needed, further include, in addition to the epoxy resin curing agent of this embodiment, low molecular weight epoxy compounds, solvents, low molecular weight acrylic compounds, organic fillers, inorganic fillers, pigments, dyes, flow modifiers, thickeners, release agents, wetting agents, flame retardants, surfactants, and resins other than epoxy resins.

[0210] Other epoxy resin curing agents besides the epoxy resin curing agent of this embodiment include nitrogen-containing compounds, phenolic curing agents, acid anhydride curing agents, and catalyst-type curing agents, which can be listed as components of the core (A) above. Other examples include active ester curing agents, cyanate ester curing agents, and thiol curing agents.

[0211] Reactive ester-based curing agents refer to curing agents that function as curing agents for epoxy resins and contain active esters in their molecules.

[0212] By including an active ester-based curing agent in the epoxy resin composition of this embodiment, hydroxyl groups, which are the inducing factors of high dielectric loss tangent, are not generated in the epoxy resin composition due to the reaction between the active ester and the epoxy group, thus tending to reduce the dielectric loss tangent.

[0213] There are no particular limitations on the active ester-based curing agent, but from the viewpoint of ensuring crosslinking density, compounds having two or more active ester groups per molecule are preferred. Furthermore, from the viewpoint of the heat resistance of the epoxy resin composition of this embodiment, active ester compounds obtained by reacting carboxylic acid compounds and / or thiocarboxylic acid compounds with hydroxyl compounds and / or thiols are more preferred. Active ester compounds obtained by reacting carboxylic acid compounds with one or more compounds selected from phenol compounds, naphthol compounds, and thiols are even more preferred. Furthermore, aromatic compounds having two or more active ester groups per molecule are obtained by reacting carboxylic acid compounds with aromatic compounds having phenolic hydroxyl groups. Even more preferred are aromatic compounds obtained by reacting carboxylic acid compounds with aromatic compounds having phenolic hydroxyl groups per molecule, and having two or more active ester groups per molecule.

[0214] Furthermore, reactive ester-based curing agents can be linear or multi-branched. Additionally, compounds containing at least two carboxylic acids per molecule tend to: improve compatibility with epoxy resins if they contain aliphatic chains; and improve heat resistance if they contain aromatic rings.

[0215] Examples of the aforementioned carboxylic acid compounds 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 the heat resistance of the epoxy resin composition of this 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 aforementioned thiocarboxylic acid compounds include, but are not specifically limited to, thioacetic acid and thiobenzoic acid.

[0217] Examples of the aforementioned phenolic or naphthol compounds include, but are not limited to, 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-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzotriethanolamine, dicyclopentadienyldiphenol, phenolic varnish, etc. From the viewpoint of the heat resistance of the epoxy resin composition of this embodiment and its solubility relative to the 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-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzotriethanolamine, dicyclopentadienyldiphenol, and phenolic varnish are preferred. Catechol, 1,5-dihydroxynaphthol, 1,6-dihydroxynaphthol, 2,6-dihydroxynaphthol, dihydroxybenzophenone, and trihydroxybenzophenone are more preferred. Tetrahydroxybenzophenone, phloroglucinol, benzotriethanolamine, dicyclopentadienyldiphenol, and phenolic varnish are further preferred, along with 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyldiphenol, and phenolic varnish. More preferably, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, dicyclopentadienyldiphenol, and phenolic varnish are also preferred. Even more preferably, dicyclopentadienyldiphenol and phenolic varnish are also preferred, and dicyclopentadienyldiphenol is particularly preferred.

[0218] Examples of the aforementioned thiols include, but are not specifically limited to, benzene dithiol and triazine dithiol.

[0219] Regarding the reactive ester compounds used as reactive ester-based curing agents, the reactive ester compounds disclosed in Japanese Patent Application Publication Nos. 2004-277460 and 2013-40270 can be used, as well as commercially available reactive ester compounds. Examples of commercially available reactive ester compounds include those manufactured by DIC Corporation under the trade names EXB9451, EXB9460, EXB9460S, HPC-8000-65T (an reactive ester compound containing a dicyclopentadiene-type diphenol structure), EXB9416-70BK (an reactive ester compound containing a naphthalene structure), and EXB9050L-62M (an reactive ester compound containing a phosphorus atom); and those manufactured by Mitsubishi Chemical Corporation under the trade names DC808 (an reactive ester compound containing an acetylated compound of phenolic varnish) and YLH1026 (an reactive ester compound containing a benzoyl compound of phenolic varnish). One or more of these compounds can be used.

[0220] Cyanate ester curing agents refer to substances that function as curing agents for epoxy resins and have cyanate ester groups in their molecules. The epoxy resin composition of this embodiment, by including a cyanate ester curing agent as another additive, imparts flexibility to the epoxy resin composition through the formation of oxazoline and oxazoline ketone rings via reaction with epoxy groups, and forms a triazine skeleton through the trimerization of cyanate ester groups. Therefore, it tends to reduce warpage and exhibit particularly good heat resistance. Furthermore, hydroxyl groups are not easily formed during the reaction, thus tending to suppress the dielectric loss tangent to a lower level.

[0221] Examples of cyanate ester curing agents include, but are not limited to, phenolic varnish-type (phenolic varnish-type, alkylphenolic varnish-type, etc.) cyanate ester resins, dicyclopentadiene-type cyanate ester resins, bisphenol-type (bisphenol A type, bisphenol F type, bisphenol S type, etc.) cyanate ester resins, and prepolymers formed by partial triazineization of these resins. Specific examples of cyanate ester resins include bisphenol A dicyanate, polyphenol cyanates (oligomeric (3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanate phenyl-1-(methylethylene))benzene, bis(4-cyanate phenyl) sulfide, bis(4-cyanate phenyl) ether, etc., difunctional cyanate ester resins; polyfunctional cyanate ester resins derived from phenolic varnishes, cresol phenolic varnishes, phenolic resins containing a dicyclopentadiene structure, etc.; and prepolymers formed by partial triazineization of these cyanate ester resins. One type or two or more types can be used in combination.

[0222] As a thiol-based curing agent, any curing agent containing two or more thiol groups in one molecule is acceptable, and is not limited to the following, but can include, for example, 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 tetra(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutyrate), dipentaerythritol hexa(3-mercaptopropionate), 1,3,4,6-tetra(2-mercaptoethyl)glycourea, 4-butanedithiol, 1,6-hexanedithiol, 1,10-decanedithiol, etc. From the viewpoint of impact resistance, 1,4-bis(3-mercaptobutyrooxy)butane, 1,3,5-tris(3-mercaptobutyroethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, pentaerythritol tetra(3-mercaptopropionate), and pentaerythritol tetra(3-mercaptobutyrate) are preferred. From the viewpoint of low-temperature curing, pentaerythritol tetra(3-mercaptopropionate) and pentaerythritol tetra(3-mercaptobutyrate) are more preferred. These can be used alone or in combination of two or more.

[0223] In this specification, low molecular weight epoxy compounds are defined as compounds other than those exemplified in the epoxy resin (C) above, with a viscosity of 1 mPa·s or more and less than 3 Pa·s at 25°C. Low molecular weight epoxy compounds are sometimes also referred to as reactive diluents.

[0224] As low-molecular-weight epoxides, examples include, but are not limited to, epoxides without aromatic rings and epoxides with aromatic rings.

[0225] Examples of monofunctional epoxy compounds that do not possess an aromatic ring include n-butyl glycidyl ether, tert-butyl glycidyl ether, allyl glycidyl ether, and 2-ethylhexyl glycidyl ether.

[0226] Examples of monofunctional epoxy compounds having one or more aromatic rings include styrene oxide, phenyl glycidyl ether, tolyl glycidyl ether, p-sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, and SY-OPG manufactured by Sakamoto Pharmaceutical Co., Ltd.

[0227] Examples of difunctional epoxides that do not possess an aromatic ring include 1,4-cyclohexanediethanol diglycidyl ether, 1,3-cyclohexanediethanol 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, dicyclopentadiene diethanol diglycidyl ether, vinylcyclohexene dioxide, and the trade name YX-8000 manufactured by Mitsubishi Chemical Corporation and the trade name SR-8EGS manufactured by Sakamoto Pharmaceutical Co., Ltd.

[0228] Examples of difunctional epoxy compounds having one or more aromatic rings include 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 trifunctional epoxy compounds include trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, and N,N-bis(2,3-epoxypropyl)-4-(2,3-epoxypropoxy)aniline.

[0230] As solvents, examples include, but are not limited to, hydrocarbons such as toluene, xylene, cyclohexane, mineral oil, 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 isopropanol, n-butanol, butyl cellosolve, butyl carbitol, and 1-methoxy-2-propanol; and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0231] Low molecular weight acrylic compounds refer to acrylic compounds with a molecular weight of less than 700. Examples include compounds with (meth)acryloyl groups at both ends of polyepoxides, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polybutylene glycol di(meth)acrylate, trimethylolpropane-type polyfunctional (meth)acrylate, pentaerythritol-type polyfunctional (meth)acrylate, dipentaerythritol-type polyfunctional (meth)acrylate, epoxy (meth)acrylate, etc.

[0232] Organic fillers function as shock absorbers that can mitigate stress caused by impact.

[0233] The epoxy resin composition of this embodiment can further improve adhesion to various connecting components by containing organic fillers. Furthermore, it tends to suppress the occurrence and aggravation of filler cracks.

[0234] Organic fillers, including but not limited to, examples such as acrylic resins, silicone resins, butadiene rubber, polyesters, polyurethanes, polyvinyl butyral, polyarylates, polymethyl methacrylate, acrylic rubbers, polystyrene, NBR, SBR, silicone-modified resins, and organic microparticles in copolymers containing them as components.

[0235] From the perspective of improving adhesion, examples of organic microparticles include (meth)acrylate alkyl ester-butadiene-styrene copolymers, (meth)acrylate alkyl ester-organosilicon copolymers, organosilicon-(meth)acrylate copolymers, organosilicon and (meth)acrylate complexes, (meth)acrylate alkyl ester-butadiene-styrene and organosilicon complexes, and (meth)acrylate alkyl ester and organosilicon complexes.

[0236] Alternatively, organic particles with a core-shell structure and different compositions of the core and shell layers can also be used as the aforementioned organic particles. Examples of core-shell organic particles include particles with an organosilicon-acrylic rubber core grafted with acrylic resin, and particles obtained by grafting acrylic resin onto an acrylic copolymer.

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

[0238] Inorganic fillers can adjust the coefficient of thermal expansion of the epoxy resin composition of this embodiment. Therefore, by containing inorganic fillers, there is a tendency to improve the heat resistance and moisture resistance when the epoxy resin composition of this embodiment is used as a bottom filler material.

[0239] As inorganic fillers, examples include, but are not limited to, silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as titanium dioxide, aluminum oxide, fused silica (e.g., 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, fused silica, crystalline silica, and synthetic silica powder are preferred from the viewpoint of improving heat resistance, moisture resistance, and strength; furthermore, any one of alumina and boron nitride is preferred. By using them, the coefficient of thermal linear expansion can be suppressed, and therefore, improvements in thermal cycling tests are expected.

[0241] The shape of inorganic fillers is not particularly limited and can be any shape, such as irregular, spherical, or scale-like.

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

[0243] As pigments, examples include, but are not limited to, kaolin, aluminum oxide trihydrate, aluminum hydroxide, chalk powder, gypsum, calcium carbonate, antimony trioxide, silicon dioxide, aerosols, zinc barium white, barite, and titanium dioxide.

[0244] As for dyes, they are not limited to the following, but can include natural dyes such as those derived from plants such as madder and indigo; dyes derived from minerals such as loess and red clay; synthetic dyes such as alizarin and indigo; and fluorescent dyes.

[0245] As flow regulators, examples include, but are not limited to, organosilane compounds such as silane coupling agents; organotitanium compounds such as tetraisopropoxide titanium and diisopropoxybis(acetylacetone)titanium; and organozirconium compounds such as tetra-n-butoxide zirconium and tetraacetylacetone zirconium.

[0246] 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 thickeners, modified polyacrylic acid thickeners, polyether thickeners, urethane-modified polyether thickeners, and carboxymethyl cellulose.

[0247] As a release agent, examples include, but are not limited to, fluorinated release agents, silicone release agents, and acrylic release agents formed from copolymers of glycidyl methacrylate and linear alkyl (meth)acrylates with 16 to 22 carbon atoms.

[0248] As a wetting agent, examples include, but are not limited to, unsaturated polyester copolymers with acidic groups such as acrylic polyphosphate esters.

[0249] Flame retardants include, but are not limited to, metal hydroxides such as aluminum hydroxide and magnesium hydroxide; halogenated 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] As surfactants, examples 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 carboxylic betaine; and nonionic surfactants such as straight-chain alcohols and fatty acid esters with more than 25 carbon atoms.

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

[0252] [Method for manufacturing epoxy resin composition]

[0253] The method for manufacturing the epoxy resin composition of this embodiment includes the following steps: obtaining a mixture of epoxy resin curing agent and epoxy resin (C) having a core (A) and a layer (B) as described in this embodiment. Examples of steps for obtaining the mixture include, but are not limited to, the following:

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

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

[0256] (3) A process of adding epoxy resin (C) to the masterbatch obtained by integrating the epoxy resin curing agent and the dispersion medium of this embodiment.

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

[0258] In addition, epoxy resin compositions obtained by considering the epoxy resin composition of this embodiment as a masterbatch type epoxy resin curing agent composition and adding epoxy resin (C) and other additive components to the masterbatch type epoxy resin curing agent composition and mixing them are also included in this embodiment.

[0259] As a mixing method, methods such as using mixing rollers such as three-roll mills, dispersers, planetary mixers, kneaders, and extruders to thoroughly mix until homogeneous can be listed.

[0260] The epoxy resin curing agent, epoxy resin composition, and epoxy resin composition mixture for films described later in this embodiment can be subjected to heat treatment at a temperature of 30°C to 80°C for 1 to 168 hours. There are no particular limitations on the heating method; methods such as heating with an oven, incubator, water bath, or oil bath can be cited. Furthermore, the temperature process is not particularly limited; for example, the temperature can be increased in stages or increased all at once. It should be noted that when heating the epoxy resin curing agent, after the formation reaction of layer (B) is completed, the epoxy resin curing agent should be left to stand in an environment below 5°C for at least 8 hours before heating.

[0261] [Specific method of epoxy resin composition]

[0262] The epoxy resin composition of this embodiment is suitable for, but is not limited to, sealing materials for electrical and electronic components such as bottom filler materials and 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, and impregnation and fixing materials for motor coils.

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

[0264] Regarding the above-described uses, the epoxy resin composition of this embodiment can be used for multiple purposes simultaneously. As an example, when the epoxy resin composition of this embodiment contains silver particles as a filler, the conductive material obtained from this epoxy resin composition can also be a thermally conductive material, but it is not limited to the above.

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

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

[0267] In conductive materials, conductive particles may include solder particles, nickel particles, nano-sized metal crystals, particles formed by covering a metal surface with other metals, gradient particles of copper and silver, and solvents. The epoxy resin curing agent of this embodiment has a robust layer (B), thereby exhibiting resistance to metal particles and solvents. Therefore, epoxy resin compositions containing the epoxy resin curing agent of this embodiment can provide conductive materials with excellent stability.

[0268] In thermally conductive materials, highly thermally conductive metals such as silver, metal oxides such as zinc oxide, ceramics such as boron nitride, aluminum nitride, and alumina, and inorganic fillers such as silica are integrated with a curing agent. Thermally and electrically conductive materials require stability during storage. Excellent stability is difficult to achieve when the curing agent and liquid components are not isolated. Even with a covering layer isolating the curing agent from the liquid components, it can be destroyed upon collision with the filler if its strength is insufficient. The epoxy resin composition containing the epoxy resin curing agent of this embodiment possesses excellent properties in these aspects and can provide a stable thermally conductive material.

[0269] Structural adhesives, typically including those for automotive structures, are often subjected to high temperature and humidity conditions after the adhesive has been applied. In such cases, excellent stability against both heat and moisture is required. Epoxy resin compositions containing the epoxy resin curing agent of this embodiment can provide structural adhesives with excellent stability against both heat and moisture.

[0270] In adhesives for camera modules, for example, when actively aligning a lens holder with an electronic component housing an image sensor such as a CMOS sensor, a dual-curing adhesive that cures by both light and heat is used. This dual-curing adhesive comprises both epoxy resin and acrylic resin. Epoxy resin compositions containing the epoxy resin curing agent of this embodiment can also provide an adhesive for camera modules that offers both sufficient stability and reactivity when both are included.

[0271] Fiber-reinforced plastic matrix resins and impregnation fixing materials for motor coils require properties from impregnation to curing, namely, permeability into the gaps of fine fibers or coils, as well as stability and curing properties during impregnation. Epoxy resin compositions containing the epoxy resin curing agent of this embodiment can possess all of these properties and are therefore suitable.

[0272] [A film comprising the epoxy resin composition of this embodiment]

[0273] A thin film having a resin composition layer comprising the epoxy resin curing agent and / or 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 films.

[0275] The film of this embodiment has, for example, a specified support and a resin composition layer formed on the support using an epoxy resin composition blending liquid described later. If necessary, a protective layer may be provided on the surface of the resin composition layer opposite to the support.

[0276] The preferred support is a material that can withstand the temperature required for drying organic solvents. Examples of such supports include, but are not limited to, 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] Stretched films may also be used as these films, depending on the requirements.

[0278] As a protective layer, a material that can adequately maintain the smoothness of the surface of the resin composition layer is preferred. Such a protective layer is not limited to the following, but polyethylene film, polypropylene film, easily peelable polyethylene terephthalate film, oriented polypropylene film, etc. are preferred.

[0279] [Preparation method of epoxy resin composition blending solution for thin films]

[0280] As a method for preparing an epoxy resin composition blending liquid for forming a resin composition layer of a thin film, examples include the following method: mixing the epoxy resin curing agent and / or epoxy resin composition of this embodiment with other additives, polymers for film formation, etc., and then adding an organic solvent, and mixing with a planetary mixer or the like.

[0281] As a polymer for film formation, any polymer that, when dried by drying the organic solvent after coating with an epoxy resin composition mixture to form a film, exhibits the effects of inhibiting cracking, shrinkage, and excessive flow, and maintaining the film shape, can be used. Examples of such polymers for film formation include, but are not limited to, phenoxy resins, polyvinyl butyral resins, polyvinyl acetal resins, polyacrylic acid resins, polyimide resins, and elastomers having functional groups such as carboxyl, hydroxyl, vinyl, and amino groups. Polymers for film formation are sometimes also referred to as adhesive polymers.

[0282] There are no particular restrictions on the use of organic solvents; any known organic solvents may be used. Examples include, but are not limited to, hydrocarbons such as toluene, xylene, cyclohexane, mineral oil, 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 amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone.

[0283] [Thin film manufacturing method]

[0284] The film of this embodiment can be manufactured by sequentially stacking a support and a resin composition layer, and a protective layer as needed.

[0285] Known methods can be used as the lamination method for the support, resin composition layer and protective layer.

[0286] For example, to prepare a mixture comprising the epoxy resin composition of this embodiment and an organic solvent, firstly, the mixture is applied to a support using a known method such as an applicator or a bar coater and dried to form a resin composition layer on the support. The drying method is not particularly limited; examples include an oven and hot air blowing. Furthermore, the drying temperature and time are not particularly limited. From the viewpoint of sufficiently removing the solvent and suppressing deformation of the support due to overheating and residual reaction of the resin composition layer during drying, drying is preferably performed within a temperature range of 50°C to 160°C and a drying time of 1 to 30 minutes; more preferably, drying is performed within a temperature range of 80°C to 150°C and a drying time of 3 to 25 minutes. It should be noted that the drying temperature can be a fixed temperature or a temperature gradient can be applied. Next, a protective layer is laminated onto the formed resin composition layer as needed to manufacture a thin film.

[0287] [Specific methods for constructing films containing the epoxy resin composition of this embodiment]

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

[0289] The epoxy resin composition of this embodiment has excellent solvent resistance and storage stability. Therefore, it is possible to extend the coating time of the epoxy resin composition mixture for film containing the composition, and to extend the shelf life of the resulting film.

[0290] Furthermore, the epoxy resin composition of this embodiment has excellent curability at temperatures below 150°C, therefore, the film of this embodiment also has excellent curability.

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

[0292] Example

[0293] The following specific embodiments and comparative examples illustrate this implementation method. However, this implementation method is not limited to the following embodiments and comparative examples.

[0294] It should be noted that the terms "parts" and "%" below are quality standards unless otherwise specified.

[0295] [Manufacturing of a nucleus (A) containing nitrogen compounds]

[0296] (Manufacturing Example 1)

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

[0298] Next, the above-mentioned substance 1 was pulverized using a jet mill, and then classified using a classifier to obtain a specific surface area of ​​3.71 m². 2 / g, average particle size under sieve D 50 It is 2.63μm and has D 99 / D 50 The core component 1 has a particle size distribution of 5.5 and contains 0.005% by mass of 2-methylimidazole (abbreviated as "2MI" in the table).

[0299] Regarding D 50 and D 99Based on the Stokes particle size obtained by laser diffraction / light scattering method using a particle size analyzer (HORIBA LA-920, manufactured by Horiba Manufacturing Co., Ltd.), the particle size with a cumulative undersize percentage of 50% for the core (A) is defined as D. 50 Let D be the particle size at which the cumulative percentage of nucleus (A) passing through the sieve is 99%. 99 (The same applies to the manufacturing examples below.)

[0300] The specific surface area was measured using a fully automated BET specific surface area measuring device HMmodel-1201 manufactured by MOUNTECH Co., Ltd., with a mixed gas of N2 / He = 30 / 70 (volume ratio) as the adsorbent gas (the same applies to the manufacturing examples below).

[0301] (Manufacturing Example 2)

[0302] Using the aforementioned core component 1, a KRYPTRON ORB manufactured by EARTHTECHNICA CO.,LTD. was used at a temperature of 10°C and humidity of 30%, with a rotational speed of 13500 rpm, a supply speed of 10 kg / hr, and an air volume of 3 m³ / h. 3 Shape correction was performed at a rate of / min. A cyclone separator and bag filter were added to the classifier for grading, resulting in a specific surface area of ​​2.51 m². 2 / g、D 50 It is 2.80μm and has D 99 / D 50 The core component 2 has a particle size distribution of 3.8 and contains 0.005% by mass of 2-methylimidazole.

[0303] (Production Example 3)

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

[0305] Next, the above-mentioned substance 2 was pulverized using a turbomill and then classified using a classifier to obtain a specific surface area of ​​3.61 m². 2 / g, average particle size under sieve D 50 It is 2.41 μm and has D 99 / D 50 The core component 3 has a particle size distribution of 5.1 and contains 0.2% by mass of 2-methylimidazole.

[0306] (Production Example 4)

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

[0308] The obtained substance 3 was pulverized using a turbomill, yielding a specific surface area of ​​3.91 m². 2 / g, average particle size under sieve D 50 It is 2.55μm and has D 99 / D 50 The core component 4 has a particle size distribution of 4.0 and contains 0.01% by mass of 2-methylimidazole.

[0309] (Production Example 5)

[0310] One equivalent (epoxy group conversion) of bisphenol A type 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 in a 1:1 mixture of xylene and isopropanol at 80 °C. Then, excess diethylenetriamine and the solvent were distilled off under reduced pressure to obtain substance 4, which is a solid at 25 °C.

[0311] 45g of substance 4, 45g of substance 1, and 11g 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 is a solid at 25°C.

[0312] Next, the above-mentioned substance 5 was pulverized using a turbomill and then classified using a classifier to obtain a specific surface area of ​​2.69 m². 2 / g, average particle size under sieve D 50 It is 2.88μm and has D 99 / D 50 It has a particle size distribution of 4.7, contains 10% by mass of 1,4-diazabicyclo[2.2.2]octane, and also contains 0.1% by mass of diethylenetriamine and 2-methylimidazole as a core component 5.

[0313] (Manufacturing Example 6)

[0314] The above-mentioned substance 1 was pulverized using a jet mill, and then classified using a classifier to obtain a specific surface area of ​​4.32 m². 2 / g, average particle size under sieve D 50 It is 2.27μm and has D99 / D 50 The core component 6 has a particle size distribution of 3.4 and contains 0.005% by mass of 2-methylimidazole.

[0315] [Example 1]

[0316] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 10 parts by weight 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 at 9°C for 12 hours (standing process) to obtain masterbatch type epoxy resin curing agent composition 1. It should be noted that temperature monitoring was performed during the above standing process to confirm the lowest temperature T from the start time t1 to the end time t2. L With the highest temperature T H The difference is less than 4℃. That is, it is confirmed that the temperature change when left to stand for 12 hours under the condition of 9℃ is within the range of 9℃±2℃ (the temperature change during the standing process is also confirmed in the same way below).

[0317] (Evaluation of staining properties of layer (B))

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

[0319] Next, toluene was added to the masterbatch type epoxy resin curing agent composition 1, and the epoxy resin and curing agent components were separated by a centrifuge. The curing agent components were collected and dried to obtain epoxy resin curing agent 1.

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

[0321] Image 1 was read using the image analysis software ImageJ (ImageJ 1.53t Java 1.8.0_345 (64-bit)). After applying a mid-range filter (Radius 2.0 pixels), line segments were drawn from the outermost layer (B) in a manner that included the boundary between the kernel (A) and layer (B), resulting in image 1'. Figure 1 The curve is obtained by plotting the brightness along this line segment. Figure 1 ( Figure 2 ).curve Figure 1 In the diagram, the vertical axis represents brightness, and the horizontal axis represents the distance between the outermost side and the end of layer (B) in the above line segment (the same applies to subsequent diagrams).

[0322] Based on the obtained image 1' and curve Figure 1 When obtaining the brightness curve from the outermost 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 1 has a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0323] [Example 2]

[0324] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 200 parts by weight of core component 2, and 10 parts by weight 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 9°C for 12 hours to obtain masterbatch type epoxy resin curing agent composition 2. It should be noted that the temperature change during the 12-hour standing period at 9°C was confirmed to be within the range of 9°C ± 2°C.

[0325] For masterbatch epoxy resin curing agent composition 2, the staining property of the contained epoxy resin curing agent 2 was confirmed in the same way as that of masterbatch epoxy resin curing agent composition 1. When obtaining the 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) has a region with a brightness higher than that of the outermost part and the aforementioned boundary.

[0326] [Example 3]

[0327] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 3, and 10 parts by weight of core surface covering 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 at 9°C for 12 hours to obtain masterbatch type epoxy resin curing agent composition 3. It should be noted that the temperature change during the 12-hour standing period at 9°C was confirmed to be within the range of 9°C ± 2°C.

[0328] For masterbatch-type epoxy resin curing agent composition 3, the staining property of epoxy resin curing agent 3 was confirmed in the same manner as that of masterbatch-type epoxy resin curing agent composition 1. That is, in image 2 obtained by image analysis of TEM observation images of epoxy resin curing agent 3, lines were drawn at specified positions to confirm the staining property, resulting in image 2' ( Figure 3 The curve is obtained by plotting the brightness along this line segment. Figure 2 ( Figure 4 Based on image 2' and curve Figure 2 When obtaining the brightness curve from the outermost 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 a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0329] [Example 4]

[0330] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 4, 4 parts by weight of core surface covering material C-1 (MR-400 manufactured by Nippon Polyurethane Co., Ltd.), and 3 parts by weight of core surface covering 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 at 9°C for 12 hours to obtain masterbatch type epoxy resin curing agent composition 4. It should be noted that the temperature change during the 12-hour standing period at 9°C was confirmed to be within the range of 9°C ± 2°C.

[0331] For masterbatch-type epoxy resin curing agent composition 4, the staining property of the contained epoxy resin curing agent 4 was confirmed in the same manner as in masterbatch-type epoxy resin curing agent composition 1. That is, in image I obtained by image analysis of TEM observation images of epoxy resin curing agent 4, lines were drawn at specified positions to confirm the staining property, resulting in image I' ( Figure 5 The brightness is plotted along this line segment to obtain curve G. Figure 6 Based on image I' and curve G, when obtaining the brightness curve from the outermost layer 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 4 has a region with a brightness higher than that of the outermost layer and the aforementioned boundary. Furthermore, in Figure 5 In the middle, the boundary between layer (B) and the area of ​​the epoxy resin composition for dyeing shows a wavy or wrinkled appearance, indicating that the surface of layer (B) is rough. It should be noted that if... Figure 5 (Epoxy resin curing agent 4) and Figure 1 (Epoxy resin curing agent 1) and Figure 3 Compared with (epoxy resin curing agent 3), in Figure 1 , 3 In the middle, the boundary between layer (B) and the area of ​​the epoxy resin composition for dyeing appears to be straight, thus indicating that the surface of layer (B) in epoxy resin curing agents 1 and 3 is a smooth surface compared to epoxy resin curing agent 4 described later.

[0332] [Example 5]

[0333] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 120 parts by weight of core component 5, and 10 parts by weight 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 9°C for 12 hours to obtain masterbatch type epoxy resin curing agent composition 5. It should be noted that the temperature change during the 12-hour standing period at 9°C was confirmed to be within the range of 9°C ± 2°C.

[0334] For the masterbatch epoxy resin curing agent composition 5, the staining property of the contained epoxy resin curing agent 5 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A), it was confirmed that the interior of the layer (B) has a region with a brightness higher than that of the outermost part and the boundary mentioned above.

[0335] [Example 6]

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

[0337] For the masterbatch epoxy resin curing agent composition 6, the staining property of the contained epoxy resin curing agent 6 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost layer of layer (B) to the boundary between layer (B) and core (A), it was confirmed that the interior of layer (B) has a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0338] [Example 7]

[0339] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 10 parts by weight 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 masterbatch type epoxy resin curing agent composition 7. It should be noted that the temperature change during the 8-hour standing period at 6°C was confirmed to be within the range of 6°C ± 2°C.

[0340] For the masterbatch epoxy resin curing agent composition 7, the staining property of the contained epoxy resin curing agent 7 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A), it was confirmed that the interior of the layer (B) has a region with a brightness higher than that of the outermost part and the boundary mentioned above.

[0341] [Example 8]

[0342] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 10 parts by weight 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 masterbatch type epoxy resin curing agent composition 8. It should be noted that the temperature change during the 24-hour standing period at 12°C was confirmed to be within the range of 12°C ± 2°C.

[0343] For the masterbatch epoxy resin curing agent composition 8, the staining property of the contained epoxy resin curing agent 8 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost layer of layer (B) to the boundary between layer (B) and core (A), it was confirmed that the interior of layer (B) has a region with a brightness higher than that of the outermost layer and the boundary mentioned above.

[0344] [Example 9]

[0345] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 6, and 10 parts by weight 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 9°C for 12 hours to obtain masterbatch type epoxy resin curing agent composition 9. It should be noted that the temperature change during the 12-hour standing period at 9°C was confirmed to be within the range of 9°C ± 2°C.

[0346] For the masterbatch epoxy resin curing agent composition 9, the staining property of the contained epoxy resin curing agent 9 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost part of the layer (B) to the boundary between the layer (B) and the core (A), it was confirmed that the interior of the layer (B) has a region with a brightness higher than that of the outermost part and the boundary mentioned above.

[0347] [Comparative Example 1]

[0348] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 10 parts by weight 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 25°C for 12 hours to obtain masterbatch type epoxy resin curing agent R-1. It should be noted that the temperature change during the 12-hour standing period at 25°C was confirmed to be within the range of 25°C ± 2°C.

[0349] For masterbatch-type epoxy resin curing agent composition R-1, the staining property of epoxy resin curing agent R-1 was confirmed in the same manner as that of masterbatch-type epoxy resin curing agent composition 1. That is, in image 3 obtained by image analysis of TEM observation image of epoxy resin curing agent 3, lines were drawn at specified positions to confirm the staining property, resulting in image 3' ( Figure 7 The curve is obtained by plotting the brightness along this line segment. Figure 3 ( Figure 8 Based on image 3' and curves Figure 3When obtaining the brightness curve from the outermost 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 does not have a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0350] [Comparative Example 2]

[0351] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 10 parts by weight 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 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 during the 24-hour standing period at 50°C was confirmed to be within the range of 50°C ± 2°C.

[0352] For the masterbatch epoxy resin curing agent composition R-2, the staining property of the contained epoxy resin curing agent R-2 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost layer of layer (B) to the boundary between layer (B) and core (A), it was confirmed that the interior of layer (B) does not have a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0353] [Comparative Example 3]

[0354] 100 parts by weight of bisphenol A type epoxy resin E-1 (epoxy equivalent 186 g / eq, total chlorine content 600 ppm, hydrolyzable chlorine content 50 ppm), 100 parts by weight of bisphenol F type epoxy resin E-2 (epoxy equivalent 172 g / eq, total chlorine content 500 ppm, hydrolyzable chlorine content 100 ppm), 100 parts by weight of core component 1, and 20 parts by weight 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 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 during the 12-hour standing period at 25°C was confirmed to be within the range of 25°C ± 2°C.

[0355] For the masterbatch epoxy resin curing agent composition R-3, the staining property of the contained epoxy resin curing agent R-3 was confirmed in the same way as that of the masterbatch epoxy resin curing agent composition 1. When a brightness curve was obtained from the outermost layer of layer (B) to the boundary between layer (B) and core (A), it was confirmed that the interior of layer (B) does not have a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0356] [Methods for evaluating characteristics]

[0357] (Stability evaluation of low molecular weight epoxy compounds)

[0358] (Preparation method of epoxy resin composition for evaluating the stability of low molecular weight epoxy compounds)

[0359] Weigh 30 parts of the masterbatch-type epoxy resin curing agent composition described in Examples 1-9 and Comparative Examples 1-3, 100 parts of jER828 (manufactured by Mitsubishi Chemical Co., Ltd.), and 30 parts of the low molecular weight epoxy compound o-CGE (o-cresol glycidyl ether; viscosity at 25°C is 7 mPa·s; manufactured by Sigma-Aldrich). Mix these components using a bubble-free kneader for 2 minutes and 3 minutes to degas, and prepare an epoxy resin composition for 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 used for stability evaluation of low molecular weight epoxy compounds was measured at room temperature (25°C) using an E-type viscometer, and the viscosity of the epoxy resin composition used for stability evaluation was measured after storage at 40°C for 21 days. The viscosity ratio after storage was calculated by the following mathematical formula (2).

[0362] Viscosity ratio after storage = Viscosity after storage / Initial viscosity ... Mathematical formula (2)

[0363] The viscosity ratio after storage is evaluated using the following criteria.

[0364] 〇: 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 compositions containing low molecular weight epoxy compounds)

[0368] Weigh approximately 10 mg of the epoxy resin composition (uncured state) used for the stability evaluation of low molecular weight epoxy compounds. Use a DSC EXSTER7020 (manufactured by Hitachi High Technology Co., Ltd.) to heat from 25°C to 250°C at a rate of 20°C / min to obtain a DSC curve. The temperature at which the heat flux reaches its maximum is taken as the DSC exothermic peak temperature.

[0369] The following criteria are used to evaluate the heat release peak temperature.

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

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

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

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

[0374] ×: 150℃ < Exothermic peak temperature

[0375] (Stability evaluation of MEK)

[0376] (Preparation method of epoxy resin composition for stability evaluation of MEK)

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

[0378] (Stability of MEK)

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

[0380] Viscosity ratio after storage = Viscosity after storage / Initial viscosity ... Mathematical formula (3)

[0381] The following criteria are used to evaluate the viscosity ratio after storage.

[0382] 〇: 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] (Stability evaluation of low molecular weight acrylic compounds)

[0386] (Preparation method of epoxy resin composition for evaluating the stability of low molecular weight acrylic compounds)

[0387] After weighing 50 parts by weight of the masterbatch-type epoxy resin curing agent composition described in Examples 1-9 and Comparative Examples 1-3, 100 parts by weight of jER828 (manufactured by Mitsubishi Chemical Co., Ltd.), and 50 parts by weight of epoxy acrylate (epoxy acrylate 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 mixed to prepare an epoxy resin composition for evaluating the stability of low molecular weight acrylic compounds.

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

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

[0390] Viscosity ratio after storage = Viscosity after storage / Initial viscosity ... Mathematical formula (4)

[0391] The following criteria are used to evaluate the viscosity ratio after storage.

[0392] 〇: 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 compositions containing low-molecular-weight acrylic compounds)

[0396] Weigh approximately 10 mg of the epoxy resin composition (uncured state) used for stability evaluation of low molecular weight acrylic compounds. Use an EXSTER 7020 (manufactured by Hitachi High Technology Co., Ltd.) to heat from 25°C to 250°C at a rate of 20°C / min to obtain the DSC curve. The temperature at which the heat flux reaches its maximum is taken as the DSC exothermic peak temperature.

[0397] The evaluation is based on the exothermic peak temperature using the following benchmarks.

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

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

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

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

[0402] ×: 150℃ < Exothermic peak temperature

[0403] (Appearance evaluation of a small area)

[0404] (Preparation method of epoxy resin composition for appearance evaluation of small areas)

[0405] Weigh 15 parts by weight of the masterbatch-type epoxy resin curing agent composition described in Examples 1-9 and Comparative Examples 1-3, 30 parts by weight of jER828 (manufactured by Mitsubishi Chemical Co., Ltd.), 5 parts by weight of the low molecular weight epoxy compound o-CGE (o-tolyl glycidyl ether; viscosity at 25°C is 7 mPa·s; manufactured by Sigma-Aldrich), and SO-E2 (spherical silica manufactured by Admatechs Co., Ltd.) as filler. 50 After mixing 50 parts by weight of (0.8 μm), these components were stirred for 2 minutes and degassed for 3 minutes using a bubble-free kneader, thereby preparing an epoxy resin composition for appearance evaluation of small areas.

[0406] (Appearance evaluation of a small area)

[0407] An epoxy resin composition for evaluating the appearance of small areas was cured in an oven at 180°C for 1 hour. The cured material was then cut with a diamond tool, polished with sandpaper, and gold was vapor-deposited onto the surface. The polished surface was then observed using SEM at 1000x magnification. The obtained SEM images were binarized, and the area ratio of unfilled regions with a circular equivalent diameter of 3 μm or more was calculated.

[0408] The following criteria are used to evaluate the area based on the proportion of unfilled regions.

[0409] 〇: Less than 5%

[0410] ×: 5% or more

[0411] Table 1 describes the weight percentage of low molecular weight amines (Molecular weight 50-300) contained in the core (A) of Examples 1-9 and Comparative Examples 1-3, the stainability of the layer (B), and the characteristics of the epoxy resin compositions prepared for each evaluation item.

[0412] It should be noted that the staining properties of layer (B) are evaluated using the following criteria.

[0413] 〇: When obtaining the brightness curve from the outermost layer of layer (B) to the boundary between layer (B) and core (A), the interior of layer (B) has regions with brightness higher than the brightness of the outermost layer and the aforementioned boundary.

[0414] ×: When obtaining the brightness curve from the outermost layer of layer (B) to the boundary between layer (B) and core (A), the interior of layer (B) does not have a region with a brightness higher than that of the outermost layer and the aforementioned boundary.

[0415] [Table 1]

[0416]

[0417] A comparison of the examples and comparative examples reveals that, when obtaining the brightness curve from the outermost layer (B) to the boundary between layer (B) and core (A), epoxy resin curing agents 1-9, which have a brightness higher than the outermost layer and the boundary between layer (B) and core (A) inside layer (B), exhibit excellent stability and reactivity for low molecular weight epoxy compounds, MEK, and low molecular weight acrylic resins.

[0418] Furthermore, it is known that, regarding the appearance of the micro-regions, when obtaining the brightness curve from the outermost layer of layer (B) to the boundary between layer (B) and core (A), the appearance of the micro-regions is excellent because the interior of layer (B) has a position with higher brightness than the outermost layer and the boundary between layer (B) and core (A). The appearance of Example 1 is shown below. Figure 9 The appearance of Comparative Example 1 is shown in Figure 10 .

[0419] Here, the results of Comparative Examples 1 to 3 show that, under the condition of heat treatment of the masterbatch type epoxy resin curing agent composition and without controlling the increase and temperature of the core surface covering material, when obtaining the brightness curve from the outermost part of layer (B) to the boundary between layer (B) and core (A), it is not possible to obtain an epoxy resin curing agent with a brightness higher than the outermost part and the boundary between layer (B) and core (A) inside layer (B).

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

[0421] Three parts by weight of bisphenol A (2,3-dihydroxypropyl) glycidyl ether (manufactured by Merck) as component (D) were further added to an epoxy resin composition used for evaluating the stability of low molecular weight epoxy compounds, which employed the masterbatch-type epoxy resin curing agent composition of Example 1. Stability and reactivity evaluations of the low molecular weight epoxy compounds were then conducted. The results showed that the stability of the low molecular weight epoxy compounds was 0, and the reactivity of the epoxy resin composition containing the low molecular weight epoxy compounds was ◎◎, indicating that reactivity was improved while maintaining stability.

[0422] The above description of this embodiment is not limited to this invention and can be appropriately modified without departing from the spirit of the invention.

[0423] Industrial availability

[0424] The epoxy resin curing agent and epoxy resin composition of this embodiment exhibit excellent reactivity and stability even when low-molecular-weight epoxy compounds, solvents, and low-molecular-weight acrylic compounds coexist, resulting in excellent appearance in minute areas. Therefore, it has industrial applicability in applications such as sealing materials for electrical and electronic components like underfill materials and relay sealing materials, conductive materials like conductive pastes, thermally conductive materials, insulating materials, adhesives for camera modules, structural adhesives, matrix resins for fiber-reinforced plastics, and impregnation and fixing materials for motor coils.

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

Claims

1. An epoxy resin curing agent, comprising: Contains a nitrogen-containing nucleus (A), and The layer (B) covering the core (A), When the epoxy resin curing agent is stained with ruthenium tetroxide and osmium tetroxide and observed with a transmission electron microscope and the brightness curve is obtained by image processing, the interior of the layer (B) contains a region with brightness α, which is higher than the brightness β of the outermost part 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) with a molecular weight of 50 to 300.

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

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

5. The epoxy resin curing agent according to claim 1, wherein, The particle size D of the core (A) having a cumulative undersize percentage of 50% 50 Larger than 0.3μm and smaller than 12μm.

6. The epoxy resin curing agent according to claim 5, wherein, The particle size D of the core (A) with a cumulative undersize percentage of 99% 99 With the D 50 The ratio of D 99 / D 50 The number is below 8.

7. The epoxy resin curing agent according to claim 5, wherein, The specific surface area Y(m²) of the core (A) 2 / g) multiplied by the stated D 50 The value obtained by (μm) is above 3.0 and below 9.

0.

8. The epoxy resin curing agent according to claim 5, wherein, The specific surface area Y(m²) of the core (A) 2 / g) multiplied by the stated D 50 The value obtained by (μm) is greater than 9.0 and less than 18.

0.

9. An epoxy resin composition comprising the epoxy resin curing agent of claim 1 and 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.

11. The epoxy resin composition according to claim 9, wherein, It also contains the alcohol compound (D) shown in formula (1) below. In formula (1), X1 represents an alkylene group having 2 or more but less than 5 carbon atoms, which may be selected as a substituent R. Substituent 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. Here, it may be selected as any of R1 to R5 that constitutes a fused ring compound.

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

13. The epoxy resin composition according to claim 11, 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.

14. The epoxy resin composition according to claim 13, wherein, The core (A) comprises 0.001 to 20% by mass of an amine compound (a) having a molecular weight of 50 to 300, wherein the amine compound (a) comprises at least one selected from the group consisting of imidazoles, aliphatic amines, and cyclic amines containing tertiary amines.

15. A sealing material comprising an epoxy resin curing agent according to any one of claims 1 to 8 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

16. A conductive material comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

17. A thermally conductive material comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

18. An insulating material comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

19. An adhesive for a camera module comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

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

21. A matrix resin for fiber-reinforced plastics, comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

22. An impregnation and fixing material comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

23. An interlayer insulating film comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

24. A thin-film solder resist comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

25. A sealing sheet comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

26. A conductive film comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

27. An anisotropic conductive film comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

28. A thermally conductive film comprising an epoxy resin curing agent according to any one of claims 1 to 3 or an epoxy resin composition according to any one of claims 9, 11, 13 and 14.

29. A method for manufacturing a dyed and cured material, comprising the 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); Step (S2) to obtain a cured product comprising the epoxy resin curing agent having undergone step (S1); and The step of electron staining the slices of the cured material with osmium tetroxide (S3).

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