JP2023070208A - epoxy resin composition - Google Patents

Abstract

To provide an epoxy resin composition which provides a cured product having excellent heat resistance and moisture resistance and is excellent in low-temperature curability and short time curing and generates less volatile components during curing.SOLUTION: There is provided an epoxy resin composition which comprises the following components (A) to (E): (A) 100 pts. mass of an epoxy resin having two or more epoxy groups in one molecule which is not modified with a silicone, (B) a thiol compound having 3 or more thiol groups in one molecule, (C) 0.5 to 100 pts. mass of a silicone-modified epoxy resin, (D) 1.0 to 200 pts. mass of a microcapsule type curing accelerator and (E) 0.05 to 10 pts. mass of a reaction inhibitor, wherein the amount of the component (B) is an amount such that the molar equivalent ratio of the thiol group in the component (B) is 0.1 to 1.0 to the total molar equivalent amount of epoxy groups in the component (A) and the component (C).SELECTED DRAWING: None

Description

The present invention relates to epoxy resin compositions. More particularly, it relates to an epoxy resin composition containing a thiol compound.

Epoxy resin compositions are excellent in adhesive strength, heat resistance and electrical properties, and are therefore used as adhesives and sealing materials in fields such as electric/electronic device parts and automobile parts. In recent years, from the viewpoint of suppressing deterioration of parts under high-temperature conditions and improving productivity, there has been a demand for an epoxy resin composition that can be cured at a low temperature in a short period of time.

A thiol-based curing agent is known as a curing agent for epoxy resin compositions that can be cured at a low temperature in a short time. For example, Patent Literature 1 and Patent Literature 2 describe a composition having an epoxy resin and a thiol compound. Patent Document 1 discloses a resin composition containing a compound that has four thiol groups in the compound and acts as a curing agent for an epoxy resin that does not have an ester bond, an epoxy resin, a curing accelerator, and a silane coupling agent. things are described. Patent document 1 describes that the thiol compound is not hydrolyzed in a hot and humid environment, and the adhesive strength is less likely to decrease. Patent Document 2 describes a resin composition containing an epoxy resin, an ester structure-containing polythiol compound, and a carbodiimide. The resin composition is described as having excellent moisture resistance. The compositions described in Patent Documents 3 and 4 use a thiol-based curing agent as a curing agent and a microcapsule-type curing agent as a curing accelerator to enable short-time curability and storage stability at low temperatures. ing.

However, conventional epoxy resin compositions containing thiol-based curing agents, such as those described in these patent documents, can be cured at low temperatures, but do not have sufficient curability because they require a long time to cure. I couldn't say I was. In addition, conventional epoxy resin compositions containing thiol-based curing agents can be cured at high temperatures in a short time from the viewpoint of improving productivity, but voids are generated in the cured product and substrates are contaminated by volatile components of the resin. Therefore, it was not satisfactory in terms of handleability. Furthermore, conventional epoxy resin compositions containing a thiol-based curing agent have a low Tg, insufficient heat resistance, and a significant decrease in adhesive strength after storage under high-temperature, high-humidity conditions. Therefore, it was not satisfactory in terms of reliability.

Patent No. 6534189 JP 2019-123825 A WO2017/057019 JP 2021-38314 A

Accordingly, an object of the present invention is to provide an epoxy resin composition which gives a cured product having excellent heat resistance and moisture resistance, is excellent in low-temperature curability and short-time curability, and contains few volatile components during curing. .

As a result of intensive studies to solve the above problems, the present inventors have found that an epoxy resin composition containing an epoxy resin, a thiol compound, a silicone-modified epoxy resin, a microcapsule-type curing accelerator and a reaction inhibitor has one molecule. By blending a specific amount of a specific thiol compound having three or more thiol groups therein, the resulting composition has excellent low-temperature curability and short-time curability, contains few volatile components during curing, and The inventors have found that a cured product having excellent heat resistance and moisture resistance can be obtained, and have completed the present invention.

That is, the present invention provides the following epoxy resin composition and the like.

[1]
An epoxy resin composition containing the following components (A) to (E).
(A) 100 parts by mass of a non-silicone-modified epoxy resin having two or more epoxy groups per molecule (B) a thiol compound having three or more thiol groups per molecule (C) a silicone-modified epoxy resin 0.5 to 100 parts by mass (D) Microcapsule type curing accelerator 1.0 to 200 parts by mass (E) Reaction inhibitor 0.05 to 10 parts by mass However, the amount of component (B) is the amount of component (A) and the molar equivalent ratio of thiol groups in component (B) to 1 molar equivalent of total epoxy groups in component (C) is 0.1 to 1.0.

[2]
The epoxy resin composition according to [1], wherein the component (B) is a thiol compound having 4 or more thiol groups per molecule.

[3]
[1] or [2], wherein the molar equivalent ratio of the thiol group in component (B) is 0.1 to 0.5 with respect to the total epoxy group molar equivalent in components (A) and (C) The epoxy resin composition described.

[4]
Component (D) is a microcapsule-type curing accelerator containing at least one selected from the group consisting of phosphorus compounds, tertiary amine compounds, imidazole compounds, urea compounds and amine adduct compounds [1] to [3 ] The epoxy resin composition according to any one of .

[5]
The epoxy resin composition according to any one of [1] to [4], wherein the component (E) is a borate compound and/or a phosphite compound.

[6]
The epoxy resin composition according to any one of [1] to [5], wherein the component (D) has a volume average particle size of 0.1 to 10 μm.

INDUSTRIAL APPLICABILITY The epoxy resin composition of the present invention has excellent low-temperature curability and short-time curability, contains few volatile components during curing, and gives a cured product having excellent heat resistance and moisture resistance. Therefore, the epoxy resin composition of the present invention is useful as an adhesive, a sealing material, and the like.

FIG. 1 is an example of a graph plotting the relationship between the dimension and temperature for the results of measuring the dimensional change of the test piece between 25 ° C. and 300 ° C. in the example. It shows how.

The epoxy resin composition of the present invention contains an epoxy resin, a thiol compound, a silicone-modified epoxy resin, a microcapsule-type curing accelerator, and a reaction inhibitor, and the thiol compound has three or more thiol groups in one molecule. It is characterized by
The present invention will be described in detail below.

(A) Epoxy resin not modified with silicone (A) Epoxy resin is the main component of the present invention, is not modified with silicone, and has two or more epoxy groups in one molecule. Furthermore, epoxy resins having one or more aromatic rings in one molecule are preferred.

The epoxy resin may have two or more, preferably three or more, epoxy groups in one molecule, and may be conventionally known epoxy resins. However, it is an epoxy resin other than the silicone-modified epoxy resin. (A) Component epoxy resins include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A Novolak type epoxy resins, novolac type epoxy resins such as bisphenol F novolac type epoxy resins, dicyclopentadiene type epoxy resins, alicyclic epoxies such as 3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate resins, polyfunctional phenol-type epoxy resins such as resorcinol-type epoxy resins and resorcinol-novolak-type epoxy resins, stilbene-type epoxy resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, trisphenol-alkane-type epoxy resins, biphenyl-type epoxy resins, Examples include xylylene-type epoxy resins, biphenylaralkyl-type epoxy resins, naphthalene-type epoxy resins, diglycidyl ether compounds of polycyclic aromatics such as anthracene, and phosphorus-containing epoxy resins into which phosphorus compounds are introduced. These can be used individually by 1 type or in combination of 2 or more types.

Component (A) preferably has a viscosity at 25° C. of 10 to 100,000 mPa·s, preferably 20 to 50,000 mPa·s. The viscosity is a value measured using a Brookfield viscometer according to JIS K 7117-1:1999.

The amount of component (A) is preferably 4 to 60% by mass, more preferably 8 to 55% by mass, even more preferably 12 to 50% by mass, relative to the total mass of the epoxy resin composition.

(B) A thiol compound having 3 or more thiol groups in one molecule Component (B) is a polythiol compound that acts as a curing agent for epoxy resins, i.e., component (A) above and component (C) described later. Hardener. Polythiol compounds have high low-temperature curability and cure epoxy resins in a short period of time at low temperatures. Component (B) is characterized by having 3 or more thiol groups per molecule, preferably 4 or more, more preferably 4 to 6 thiol groups per molecule. If the number of thiol groups is 2 or less per molecule, the glass transition temperature of the resulting cured product is low, and the heat resistance and moisture resistance are poor, which is not preferable.

Examples of polythiol compounds include aliphatic polythiol compounds, aromatic polythiol compounds, polythiol compounds having ether bonds, polythiol compounds having ester bonds, and polythiol compounds such as mercaptoalkyl glycoluril compounds.
Polythiol compounds having an ester bond include, for example, trimethylolpropane tris(3-mercaptopropionate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis(3-mercaptopropionate dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), 1,3,5-tris (3-mercaptobutyryloxyethyl)-1,3,5 -triazine-2,4,6(1H,3H,5H)-trione.
Mercaptoalkyl glycoluril compounds include, for example, 1,3,4,6-tetrakis(mercaptomethyl)glycoluril, 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, 1,3,4, 6-tetrakis(3-mercaptopropyl)glycoluril, 1,3,4,6-tetrakis(mercaptomethyl)-3a-methylglycoluril, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a- methyl glycol uril, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a-methyl glycol uril, 1,3,4,6-tetrakis(mercaptomethyl)-3a,6a-dimethyl glycol uril, 1, 3,4,6-tetrakis(2-mercaptoethyl)-3a,6a-dimethylglycoluril, 1,3,4,6-tetrakis(3-mercaptopropyl)-3a,6a-dimethylglycoluril, 1,3, 4,6-tetrakis(mercaptomethyl)-3a,6a-diphenylglycoluril, 1,3,4,6-tetrakis(2-mercaptoethyl)-3a,6a-diphenylglycoluril, 1,3,4,6- Examples include, but are not limited to, tetrakis(3-mercaptopropyl)-3a,6a-diphenylglycoluril.
These may be used singly or in combination of two or more.

In the epoxy resin composition of the present invention, the polythiol compound has a molar equivalent ratio of the thiol groups in the polythiol compound of 0.1 to 1 molar equivalent of all epoxy groups in the component (A) and the component (C) described later. It is characterized by being contained in an amount of 1.0. Preferably, the molar equivalent ratio is preferably 0.1 to 0.8, more preferably 0.1 to 0.5, still more preferably 0.2 to 0.5, particularly preferably 0.2 to 0.4. is the amount. If the corresponding amount ratio is less than 0.1, the low-temperature curability may be impaired, unreacted epoxy groups may remain, and the glass transition temperature may decrease or the adhesion may decrease. On the other hand, if it exceeds 1.0, unreacted thiol groups may remain and cracks may occur during reflow or temperature cycling.
In the present invention, the equivalent weight is the molecular weight per functional group. Thiol equivalent means active hydrogen equivalent. The equivalent ratio (molar equivalent ratio) is the ratio of the thiol equivalent (active hydrogen equivalent) in the thiol compound (B) to 1 equivalent of the epoxy contained in the components (A) and (C), and is 0.1. The thiol compound (B) may be blended in an amount containing thiol active hydrogen that provides an equivalent ratio of up to 1.0, preferably in the range described above.

(C) Silicone-modified epoxy resin Component (C) is a silicone-modified epoxy resin. Containing a silicone-modified epoxy resin improves the curability and humidity resistance reliability of the epoxy resin composition. Examples of the silicone-modified epoxy resin include copolymers obtained by reacting an alkenyl group-containing epoxy resin with an organohydrogenpolysiloxane. Examples of alkenyl group-containing epoxy resins include those represented by the following formulas (1) to (3).

In the above formulas (1) to (3), R ¹ is a glycidyl group (2,3-epoxypropyl group), X is independently a hydrogen atom or a bromine atom, n is a number of 0 or more, preferably 0 to 50, more preferably a number from 1 to 20. m is an integer of 0 or more, preferably a number from 1 to 5, more preferably 1;

Examples of organohydrogenpolysiloxane include compounds represented by the following average compositional formula (4).
H _a (R ² ) _b SiO _(4-ab)/2 (4)

In the above formula (4), R ² is independently a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, a hydroxy group, an alkoxy group having 1 to 10 carbon atoms or 2 to 10 carbon atoms. is an alkenyloxy group of Examples of monovalent hydrocarbon groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group and octyl group. , an alkyl group such as a decyl group, an aryl group such as a phenyl group and a tolyl group, an aralkyl group such as a benzyl group and a phenylethyl group, and some or all of the hydrogen atoms of these hydrocarbon groups substituted with halogen atoms etc. Examples thereof include halogen-substituted monovalent hydrocarbon groups. Examples of alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, n-hexyloxy and the like. Examples of alkenyloxy groups include vinyloxy groups, propenoxy groups, isopropenoxy groups, and the like.

In the above formula (4), a and b are numbers satisfying 0.001 ≤ a ≤ 1, 1 ≤ b ≤ 3, 1 < a + b ≤ 4, preferably 0.01 ≤ a ≤ 0.1, 1 .8≤b≤2 and 1.85≤a+b≤2.1.

The organohydrogenpolysiloxane represented by the above formula (4) desirably has 1 to 1,000, preferably 2 to 400, more preferably 5 to 200 silicon atoms per molecule. Examples of the organohydrogenpolysiloxane include compounds represented by formula (5).

In formula (5) above, R ² is the same as above, preferably a methyl group or a phenyl group. p is a number from 0 to 1,000, preferably from 3 to 400; q is a number from 0 to 20, preferably from 0 to 5; more preferably q=0. Furthermore, p+q is a number that satisfies 1<p+q≦1,000, preferably 2<p+q<400, and more preferably 5<p+q<200.

Examples of such organohydrogenpolysiloxanes include compounds of the following formulas.

The organohydrogenpolysiloxane preferably has a weight average molecular weight of 100-100,000, more preferably 500-20,000. When the weight-average molecular weight of the organohydrogenpolysiloxane is within the above range, the organohydrogenpolysiloxane is distributed uniformly in the matrix depending on the structure or weight-average molecular weight of the alkenyl group-containing epoxy resin to be reacted with the organohydrogenpolysiloxane. A uniform structure dispersed in the matrix or a sea-island structure in which the organohydrogenpolysiloxane forms fine layer separation in the matrix appears.

A homogeneous structure is formed when the weight average molecular weight of the organohydrogenpolysiloxane is relatively low, especially between 100 and 10,000. Also, when the weight-average molecular weight of the organohydrogenpolysiloxane is relatively large, particularly in the range of 10,000 to 100,000, a sea-island structure is formed. Either the uniform structure or the sea-island structure may be selected depending on the application. If the weight average molecular weight of the organohydrogenpolysiloxane is less than 100, the resulting cured product will be rigid and brittle, which is not preferred. Also, if the weight average molecular weight of the organohydrogenpolysiloxane is more than 100,000, the sea-island structure becomes large, and local stress occurs in the resulting cured product, which is not preferable.

In the present specification, the weight average molecular weight is the weight average molecular weight measured by gel permeation chromatography (GPC) using polystyrene as a standard substance, and is a value measured under the following conditions.
[GPC measurement conditions]
Developing solvent: tetrahydrofuran Flow rate: 0.6 mL/min
Column: TSK Guard column SuperH-L
TSKgel Super H4000 (6.0 mm I.D. x 15 cm x 1)
TSKgel Super H3000 (6.0mm I.D. x 15cm x 1)
TSKgel SuperH2000 (6.0mm I.D. x 15cm x 2)
(both manufactured by Tosoh Corporation)
Column temperature: 40°C
Sample injection volume: 20 μL (sample concentration: 0.5% by mass-tetrahydrofuran solution)
Detector: differential refractometer (RI)

As a method for reacting an alkenyl group-containing epoxy resin and an organohydrogenpolysiloxane, a known method can be used. For example, an alkenyl group-containing epoxy resin and an organohydrogenpolysiloxane are reacted in the presence of a platinum-based catalyst. A method of addition reaction is mentioned. Thus, a silicone-modified epoxy resin can be obtained. The organohydrogenpolysiloxane is preferably copolymerized in such an amount that SiH groups possessed by the organohydrogenpolysiloxane are 0.1 to 1 mol per 1 mol of alkenyl groups possessed by the alkenyl group-containing epoxy resin.

The amount of silicone-modified epoxy resin (C) in the composition of the present invention is 0.5 to 100 parts by mass, preferably 1 to 80 parts by mass, based on 100 parts by mass of component (A). It is preferably 2 to 60 parts by mass.

(D) Microcapsule-type curing accelerator Component (D) is a microcapsule-type curing accelerator that accelerates the reaction between the epoxy resins (A) and (C) above and the thiol compound (B). The curing accelerator (catalyst) used as an active ingredient in the core material (core particles) of the microcapsules must be adjusted to the reaction temperature ( That is, the temperature at which the catalytic action is exhibited is preferably 50° C. or higher. Examples of such curing accelerators include phosphorus compounds, tertiary amine compounds, imidazole compounds, urea compounds and amine adduct compounds.

Examples of the phosphorus compounds include tributylphosphine, triphenylphosphine, tri(methylphenyl)phosphine, tri(nonylphenyl)phosphine, tri(methoxyphenyl)phosphine, diphenyltolylphosphine, triphenylphosphine/triphenylborane and the like. organophosphine compounds; quaternary phosphonium salts such as tetraphenylphosphonium and tetraphenylborate; Among these, triphenylphosphine and tri(methylphenyl)phosphine are preferred.

Examples of the tertiary amine compounds include amine compounds having an alkyl group or an aralkyl group as a substituent bonded to the nitrogen atom, such as triethylamine, benzyldimethylamine, benzyltrimethylamine, α-methylbenzyldimethylamine; diazabicyclo[5.4.0]undecene-7 and 1,4-diazabicyclo[2.2.2]octane and its phenol salts, octylate salts, cycloamidine compounds such as oleates, and salts thereof with organic acids Salts or complex salts with quaternary boron compounds, and the like are included. Among these, 1,8-diazabicyclo[5.4.0]undecene-7 and 1,4-diazabicyclo[2.2.2]octane are preferred.

Examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2,4-dimethylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 1,2-diethyl imidazole, 2-phenyl-4-methylimidazole, 2,4,5-triphenylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2- methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-allyl-4,5-diphenylimidazole, 2-phenyl-4 -methyl-5-hydroxymethylimidazole and the like. Among these, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2,4-dimethylimidazole, 2-phenyl-4-methylimidazole are preferred.

Examples of the urea compounds include N,N-dimethyl-N'-phenylurea, N,N-dimethyl-N'-(3,4-dichlorophenyl)urea, 4,4'-methylenebis(phenyldimethylurea), aromatic dimethylurea compounds, aliphatic dimethylurea compounds, toluenebisdimethylurea, dimethylaminocarboxylaminomethyltrimethylcyclohexyldimethylurea and the like. Among these, aromatic dimethylurea compounds and aliphatic dimethylurea compounds are preferred.

Examples of the amine adduct compound include compounds having an amino group obtained by reacting at least one compound selected from the group consisting of carboxylic acid compounds, phenol compounds, isocyanate compounds, and epoxy resins with an amine compound. are mentioned.

Examples of carboxylic acid compounds include succinic acid, adipic acid, sebacic acid, phthalic acid, dimer acid and the like.

Examples of phenol compounds include monophenols such as carbolic acid, cresol, xylenol, carvacrol, motyl and naphthol, and polyhydric phenols such as catechol, resorcin, hydroquinone, bisphenol A, bisphenol F, pyrogallol and phloroglucin.

Examples of isocyanate compounds include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4-4′-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1, 3-bis(isocyanatomethyl)-cyclohexane, 1,3-bis(2-isocyanatopropyl-2-yl)-cyclohexane, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, and the like.

Examples of epoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, para-xylyl glycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, Bisphenol type epoxy resin such as bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolac type epoxy resin, novolac type epoxy resin such as bisphenol F novolac type epoxy resin, dicyclopentadiene type epoxy resin , 3,4-epoxycyclohexenylmethyl-3′,4′-epoxycyclohexene carboxylate and other alicyclic epoxy resins, resorcinol-type epoxy resins, polyfunctional phenol-type epoxy resins such as resorcinol-novolak-type epoxy resins, stilbene-type epoxy Resins, triazine skeleton-containing epoxy resins, fluorene skeleton-containing epoxy resins, triphenolalkane-type epoxy resins, biphenyl-type epoxy resins, xylylene-type epoxy resins, biphenylaralkyl-type epoxy resins, naphthalene-type epoxy resins, and polycyclic aromatics such as anthracene and phosphorus-containing epoxy resins obtained by introducing a phosphorus compound into these diglycidyl ether compounds.

Examples of amine compounds include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, 1,2-propanediamine, tetramethyleneamine, 1,5-diaminopentane, hexamethylenediamine, and 2,4,4-trimethylhexamethylene. Diamine, 2,2,4-triethylhexamethyldiamine, 1,2-diaminopropane, diethylenetriamine, triethylenetetramine, tetraethylene pen, cyclohexylamine, isophoronediamine, 1,3-bisaminomethylcyclohexane, aminoethylpiperazine, diethylamino Propylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperazine and the like.

Among these, an amine adduct compound obtained by reacting an isocyanate resin or an epoxy resin with an amine compound is preferred.

These curing accelerators can be used singly or in combination of two or more.

The shell material for microencapsulating the curing accelerator should have a melting point of 50 to 90° C. from the viewpoint of maintaining storage stability and ensuring rapid curing. The material of the shell material is not particularly limited as long as it has such a melting point, and all known materials can be used. , Alkyl esters having 1 to 8 carbon atoms such as crotonic acid esters; Those in which the alkyl groups of these alkyl esters have substituents such as allyl groups; monofunctional monomers; and polyfunctional monomers such as ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, divinylbenzene, bisphenol A di(meth)acrylate, methylenebis(meth)acrylamide, etc. Examples thereof include polymers obtained by (co)polymerizing one or more monomers. Among these, polymers of (meth)acrylate monomers are preferred.

The microcapsule-type curing accelerator of component (D) is a microcapsule containing such a shell material and a curing accelerator such as an imidazole compound or a tertiary amine compound as a core component. ) to (c), but not limited thereto.

(a) After dissolving or dispersing the core particles of the shell material and the microcapsule-type curing accelerator in a solvent that is a dispersion medium, the solubility of the shell material in the dispersion medium is lowered to remove the microcapsule-type curing accelerator. A method of depositing a shell on the surface of a core particle.

(b) A method of dispersing core particles of a microcapsule-type curing accelerator in a dispersion medium, adding the shell material to the dispersion medium, and precipitating them on the core particles of the microcapsule-type curing accelerator.

(c) A method of adding the above shell material to a dispersion medium and forming a shell on the surface of the core particle of the microcapsule-type curing accelerator as a reaction site.

Examples of the dispersion medium used in the production methods (a) to (c) include solvents and resins.
Solvents include, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, n-butyl acetate, propylene glycol monomethyl ethyl ether acetate, benzene, toluene, xylene, cyclohexane, methanol, ethanol, isopropanol, n-butanol, butyl carbi Toll, water and the like can be mentioned.
Examples of resins include epoxy resins, phenol resins, maleimide resins, cyanate ester resins, and silicone resins.
Among these, aromatic hydrocarbons such as toluene and alcohols such as n-butanol are preferred as dispersion media having good dispersibility.

The microcapsule-type hardening accelerator obtained by such a method preferably has an average particle size of 0.1 to 10 μm, more preferably an average particle size of 1 to 5 μm. If the average particle size is too small, the specific surface area increases and the viscosity of the epoxy resin composition may increase when mixed. On the other hand, if the average particle diameter exceeds 10 μm, the dispersion in the epoxy resin composition may become non-uniform, resulting in a decrease in reliability. The average particle size is the volume average particle size determined by laser diffraction method.

Component (D) is added in an amount of 1.0 to 200 parts by mass, preferably 5 to 150 parts by mass, per 100 parts by mass of the epoxy resin (A). If the amount of component (D) is 1.0 to 200 parts by mass, the balance between heat resistance and moisture resistance of the cured product of the composition will be poor, and the curing speed during molding will be very slow or fast. There is no risk of

(E) Reaction Inhibitor (E) Reaction inhibitor is added for the purpose of improving storage stability, and all known ones can be used without particular limitation. Examples of the reaction inhibitor include boric acid ester compounds, aluminum chelate compounds, phosphite ester compounds, and organic acids. Among them, boric acid ester compounds and phosphite ester compounds are preferred.

Examples of boric acid ester compounds include trimethylborate, triethylborate, tri-n-propylborate, triisopropylborate, tri-n-butylborate, tripentylborate, triallylborate, trihexylborate, tricyclohexylborate, trioctyl Borate, trinonylborate, tridecylborate, tridodecylborate, trihexadecylborate, trioctadecylborate, tris(2-ethylhexyloxy)borane, bis(1,4,7,10-tetraoxaundecyl) (1 ,4,7,10,13-pentaoxatetradecyl)(1,4,7-trioxaundecyl)borane, tribenzylborate, triphenylborate, tri-o-tolylborate, tri-m-tolylborate, triethanolamine borate and the like. Among these, triisopropylborate is preferred.

Examples of aluminum chelate compounds include triethylaluminate, tripropylaluminate, triisopropylaluminate, tributylaluminate, trioctylaluminate and the like.

Phosphite compounds include, for example, phosphorous acid, monomethyl phosphite, dimethyl phosphite, monoethyl phosphite, diethyl phosphite, monobutyl phosphite, dibutyl phosphite, monolauryl phosphite, Dilauryl phosphite, monooleyl phosphite, dioleyl phosphite, monophenyl phosphite, diphenyl phosphite, mononaphthyl phosphite, dinaphthyl phosphite, di-o-tolyl phosphite, di-phosphite m-tolyl, di-p-tolyl phosphite, di-p-chlorophenyl phosphite, di-p-bromophenyl phosphite, di-p-fluorophenyl phosphite and the like. Among these, phosphorous acid is preferred. These reaction inhibitors can be used singly or in combination of two or more.

The blending amount of component (E) is 0.05 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and still more preferably 0.1 part per 100 parts by mass of the epoxy resin (A). ~3 parts by mass. When the amount of component (E) is 0.05 to 10 parts by mass, the effect of suppressing the reaction is sufficiently obtained, and there is no risk of lowering Tg or lowering bending strength due to poor curing.

Other Additives The epoxy resin composition of the present invention is obtained by blending predetermined amounts of the above components (A) to (E), and other additives are added as necessary to achieve the object and effect of the present invention. It can be added as long as it does not damage. Such additives include inorganic fillers, flame retardants, ion trapping agents, antioxidants, adhesion imparting agents, stress reducing agents, coloring agents, coupling agents, and the like.

The inorganic filler is added for the purpose of reducing the thermal expansion coefficient of the epoxy resin composition and improving the humidity resistance reliability. Preferably, the inorganic filler is spherical. As used herein, the term "spherical" refers to particles having an aspect ratio of 2.0 or less, preferably 1.5 or less. By using spherical particles as the inorganic filler, the viscosity of the epoxy resin composition can be further reduced, and the epoxy resin can be suitably liquid at 25°C.

Examples of inorganic fillers include silicas such as fused silica, crystalline silica and cristobalite; metal oxides such as aluminum oxide, titanium oxide and magnesium oxide; and nitrides such as silicon nitride, aluminum nitride and boron nitride. etc. Among them, silicas are preferably used in consideration of availability of materials, stability of quality, and the like. The average particle size of these inorganic fillers is preferably 0.01 to 50 μm, more preferably 0.05 to 30 μm, and can be selected depending on the application. The average particle size may be, for example, a volume average particle size measured by a laser diffraction method. Moreover, the kind of inorganic filler can also be used individually by 1 type or in combination of 2 or more types.

The inorganic filler is preferably surface-treated in advance with a coupling agent such as a silane coupling agent or a titanate coupling agent in order to strengthen the bonding strength between the resin component and the inorganic filler. Such coupling agents include epoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N -β(aminoethyl)-γ-aminopropyltrimethoxysilane, reaction product of imidazole and γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. and mercaptosilanes such as γ-mercaptopropyltrimethoxysilane and γ-(thiiranylmethoxy)propyltrimethoxysilane. The amount of the coupling agent used for the surface treatment and the surface treatment method are not particularly limited. The coupling agent may be separately added to the composition of the present invention as component (F).

The content of the inorganic filler in the composition of the present invention is preferably 20 to 1,200 parts by mass, more preferably 50 to 1,000 parts by mass, based on the total 100 parts by mass of (A) to (E). More preferably 100 to 800 parts by mass.

The flame retardant is added for the purpose of imparting flame retardancy, and any known flame retardant can be used without particular limitation. Examples of the flame retardant include phosphazene compounds, silicone compounds, zinc molybdate-supported talc, zinc molybdate-supported zinc oxide, aluminum hydroxide, magnesium hydroxide, molybdenum oxide and the like.

The ion trap agent is added for the purpose of trapping ionic impurities contained in the resin composition and preventing thermal deterioration and hygroscopic deterioration, and all known agents can be used without particular limitation. Examples of ion trapping agents include hydrotalcites, bismuth hydroxide compounds, rare earth oxides, and the like.

Although the amount of the above-mentioned other components to be blended varies depending on the use of the epoxy resin composition of the present invention, it is usually sufficient that the total amount is 5% by mass or less of the entire composition.

Method for Producing Epoxy Resin Composition The method for producing the epoxy resin composition of the present invention is not particularly limited.
For example, (A) a non-silicone-modified epoxy resin, (B) a thiol compound, (C) a silicone-modified epoxy resin, (D) a microcapsule-type curing accelerator, and (E) a reaction inhibitor, simultaneously or separately. The composition may be obtained by mixing, stirring, dissolving and/or dispersing while performing heat treatment as necessary. In addition, depending on the application, at least one of other additives such as inorganic fillers, flame retardants, ion trapping agents and coupling agents is added to the mixture of components (A) to (E) and mixed. An inventive epoxy resin composition can be obtained.

The epoxy resin composition of the present invention is preferably liquid at 25°C. The viscosity of the composition is preferably 1 to 650 Pa·s, more preferably 5 to 500 Pa·s at 25°C. Viscosity is measured using an E-type viscometer according to JIS Z 8803:2011.

There are no particular restrictions on the method for producing the composition and the apparatus for mixing, stirring and dispersing. For example, a Raikai machine equipped with a stirring and heating device, a two-roll mill, a three-roll mill, a ball mill, a planetary mixer, a masscolloider, or the like can be used, and these devices can be used in appropriate combination. The curing conditions of the epoxy resin composition are not particularly limited, but for example, the temperature may be in the range of 60 to 200° C., preferably 80 to 180° C., for 30 minutes to 10 hours, preferably 1 to 5 hours. The epoxy resin composition of the present invention can be cured at a low temperature in a short period of time. Therefore, it can be cured satisfactorily at a temperature in the range of 70° C. to 130° C. for about 10 minutes to 2 hours.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Components used in Examples and Comparative Examples are as follows.
(A) Epoxy resin not modified with silicone (A1) Epoxy resin: Mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin (ZX1059, viscosity at 25 ° C. 1,900 to 2,600 mPa s: Nippon Steel & Sumitomo Metal chemical company)
(A2) Epoxy resin: naphthalene type epoxy resin (HP4032D, viscosity at 25°C: 25 Pa s: manufactured by DIC Corporation)

(B) Thiol compound (B1) Thiol compound: 1,3,4,6-tetrakis(2-mercaptoethyl) glycoluril (TS-G, manufactured by Shikoku Kasei Kogyo Co., Ltd.)
(B2) Thiol compound: 1,3,4,6-tetrakis(3-mercaptopropyl) glycoluril (C3TS-G, manufactured by Shikoku Kasei Kogyo Co., Ltd.)
(B3) thiol compound: pentaerythritol tetrakis (3-mercaptobutyrate) (Kalenz MT PE1, manufactured by Showa Denko)
(B4) Thiol compound: 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (Karens MT NR1, manufactured by Showa Denko)
(B5) Comparative thiol compound: tetraethylene glycol bis(3-mercaptopropionate) (EGMP-4, manufactured by SC Organic Chemical Co., Ltd.)

で表されるアリルグリシジルエーテルで変性されたフェノールノボラック樹脂（フェノール当量１２５、アリル当量１，１００）２００ｇ、クロロメチルオキシラン８００ｇ、セチルトリメチルアンモニウムブロマイド０．６ｇをそれぞれ入れて加熱し、温度１１０℃で３時間撹拌混合した。これを冷却して温度７０℃とし、１６０ｍｍＨｇに減圧してから、この中に水酸化ナトリウムの５０％水溶液１２８ｇを共沸脱水しながら３時間かけて滴下した。得られた内容物を減圧して溶剤を留去し、次いでメチルイソブチルケトン３００ｇとアセトン３００ｇの混合溶剤にて溶解させた後、水洗し、これを減圧下で溶剤留去して下記式（７）

で表されるアリル基含有のエポキシ樹脂（アリル当量１５９０、エポキシ当量１９０）を得た。このエポキシ樹脂とメチルイソブチルケトン１７０ｇ、トルエン３３０ｇ、２質量％の白金濃度の２－エチルヘキサノール変性塩化白金酸溶液０．０７ｇを入れ、１時間の共沸脱水を行ない、還流温度にて下記式（８）

で表されるオルガノポリシロキサン１３３ｇ（重量平均分子量８０００）を滴下時間３０分にて滴下した。更に、同一温度で４時間撹拌して反応させた後、得られた内容物を水洗し、溶剤を減圧下で留去したところ黄白色不透明固体の共重合体が得られた。エポキシ当量は２８０であり、ＡＳＴＭ Ｄ４２８７に従い、コーン／プレート粘度計を用いて測定した１５０℃でのＩＣＩ溶融粘度は８００ｍＰａ・ｓであり、ケイ素含有量３１質量％であった。 (C) Silicone-modified epoxy resin To a four-necked flask with an internal volume of 1 liter equipped with a reflux condenser, a thermometer, a stirrer and a dropping funnel, the following formula (6)

200 g of a phenol novolac resin modified with allyl glycidyl ether (phenol equivalent 125, allyl equivalent 1,100), 800 g of chloromethyloxirane, and 0.6 g of cetyltrimethylammonium bromide were added and heated to 110°C. Stir and mix for 3 hours. After cooling to 70° C. and reducing the pressure to 160 mmHg, 128 g of a 50% aqueous solution of sodium hydroxide was added dropwise over 3 hours while azeotropically dehydrating. The content obtained is depressurized to distill off the solvent, then dissolved in a mixed solvent of 300 g of methyl isobutyl ketone and 300 g of acetone, washed with water, and the solvent is distilled off under reduced pressure to give a residue of the following formula (7 )

An allyl group-containing epoxy resin represented by (1590 allyl equivalent, 190 epoxy equivalent) was obtained. This epoxy resin, 170 g of methyl isobutyl ketone, 330 g of toluene, and 0.07 g of a 2-ethylhexanol-modified chloroplatinic acid solution with a platinum concentration of 2% by mass are added, and azeotropic dehydration is performed for 1 hour. 8)

133 g of organopolysiloxane represented by (weight average molecular weight: 8000) was added dropwise for 30 minutes. Further, after reacting with stirring at the same temperature for 4 hours, the content obtained was washed with water, and the solvent was distilled off under reduced pressure to obtain a yellowish white opaque solid copolymer. The epoxy equivalent weight was 280, the ICI melt viscosity at 150° C. was 800 mPa·s, measured using a cone/plate viscometer according to ASTM D4287, and the silicon content was 31% by weight.

(D) Microcapsule-type curing accelerator (D1) Tertiary amine-based microcapsule-type curing accelerator (HX5945HP, average particle size 2 μm, manufactured by Asahi Kasei Corporation)
(D2) Imidazole-based microcapsule-type curing accelerator (HX9322HP, average particle size 2 μm, manufactured by Asahi Kasei Corporation)
(D3) Imidazole-based microcapsule-type curing accelerator (HX3941HP, average particle size 5 μm, manufactured by Asahi Kasei Corporation)

Curing accelerator for comparative example (non-microcapsule type curing accelerator)
(D4) 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ-PW, manufactured by Shikoku Kasei Co., Ltd.)
(D5) Amine-epoxy adduct-based latent curing catalyst (trade name: Fujicure FXR-1081, manufactured by T&K TOKA Co., Ltd.)

(E) reaction inhibitor (E1) triisopropyl borate (manufactured by Tokyo Chemical Industry Co., Ltd.)
(E2) phosphorous acid (manufactured by Tokyo Chemical Industry Co., Ltd.)

(F) Other additives (F1) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

Each of the above components was mixed in the amounts (parts by mass) shown in Tables 1 and 2 to obtain an epoxy resin composition. Each composition and a cured product obtained by curing each composition were evaluated for viscosity, storage stability, adhesive strength, glass transition temperature (Tg), heat resistance, moisture resistance, and drop resistance by the methods shown below. An evaluation test was performed. The results are shown in Tables 1 and 2. The "molar equivalent ratio" described in Tables 1 and 2 is the ratio of the thiol equivalent (active hydrogen equivalent) in component (B) to the epoxy equivalent in components (A) and (C). means molar equivalents.

(1) Measurement of Viscosity The epoxy resin compositions obtained in Examples 1 to 17 and Comparative Examples 1 to 7 were liquid at 25°C. According to JIS Z 8803:2011, the viscosity was measured 2 minutes after setting the sample using an E-type viscometer at a measurement temperature of 25°C (initial viscosity).

(2) Confirmation of Storage Stability The viscosity of each epoxy resin composition after being held at 25° C. for 24 hours was measured in the same manner as described above. Storage stability was evaluated by determining the rate of change (%) of the viscosity after 24 hours with respect to the initial viscosity.

(3) Adhesive strength after low-temperature curing Each epoxy resin composition of Examples and Comparative Examples was poured into a mold to obtain a truncated cone-shaped test piece having an upper surface diameter of 2 mm, a lower surface diameter of 5 mm, and a height of 3 mm. The test piece was placed on an aluminum plate and cured at 80° C. for 10 minutes. After curing, the resulting test piece was cooled to room temperature and the shear adhesion was measured.

(4) Adhesive strength after high-temperature curing Each epoxy resin composition of Examples and Comparative Examples was poured into a mold to obtain a truncated cone-shaped test piece with an upper surface diameter of 2 mm, a lower surface diameter of 5 mm, and a height of 3 mm. The test piece was placed on an aluminum plate and cured at 180° C. for 10 seconds. After curing, the resulting test piece was cooled to room temperature and the shear adhesion was measured.

Preparation of Cured Material Samples The epoxy resin compositions of Examples and Comparative Examples were cured by heating at 80° C. for 1 hour and further at 120° C. for 1 hour to obtain cured products.

(5) Measurement of glass transition temperature (Tg) After processing each of the cured products obtained above into test pieces of 5 × 5 × 15 mm, the test pieces were measured with a thermal expansion meter TMA8140C (manufactured by Rigaku Corporation). set to Then, the heating program was set to a heating rate of 5°C/min and a constant load of 19.6 mN was applied, and then the dimensional change of the test piece was measured between 25°C and 300°C. The relationship between this dimensional change and temperature was plotted on a graph (an example of the graph is shown in FIG. 1). From the thus obtained graph of dimensional change and temperature, the glass transition temperature in Examples and Comparative Examples was determined by the method for determining the glass transition temperature described below.

Method for determining _glass transition temperature (Tg) As shown in _FIG . T ₁ ' and T ₂ ' are two arbitrary temperature points at which similar tangents are obtained above the temperature. D ₁ and D ₂ are the dimensional changes at T ₁ and T ₂ respectively, a straight line connecting points (T ₁ , D ₁ ) and points (T ₂ , D ₂ ), and dimensional changes at T ₁ ' and T ₂ ' are D ₁ ' and D ₂ ', respectively, and the intersection of a straight line connecting the points (T ₁ ', D ₁ ') and the points (T ₂ ', D ₂ ') was taken as the glass transition temperature (T _g ).

(6) Heat resistance (adhesive strength retention after storage at 150°C)
Each epoxy resin composition of Examples and Comparative Examples was poured into a mold to obtain a truncated cone-shaped test piece having an upper surface diameter of 2 mm, a lower surface diameter of 5 mm, and a height of 3 mm. The test piece was placed on an aluminum plate and cured by heating at 80° C. for 1 hour and then at 120° C. for 1 hour. After curing, the obtained test piece was cooled to room temperature and the shear adhesive strength was measured, and the measurement result was used as the initial value. After storing the obtained test piece in an oven at 150° C. for 150 hours, it was cooled to room temperature and the shear adhesive strength was measured. More specifically, the adhesive strength retention after storage at 150°C was calculated by the following formula.

(7) Humidity resistance (adhesive strength retention after PCT storage)
Each epoxy resin composition of Examples and Comparative Examples was poured into a mold to obtain a truncated cone-shaped test piece having an upper surface diameter of 2 mm, a lower surface diameter of 5 mm, and a height of 3 mm. The test piece was placed on an aluminum plate and cured by heating at 80° C. for 1 hour and then at 120° C. for 1 hour. After curing, the obtained test piece was cooled to room temperature and the shear adhesive strength was measured, and the measurement result was used as the initial value. The resulting test piece was stored at PCT (121° C./100% humidity/2 atm) for 96 hours, cooled to room temperature, and shear adhesive strength was measured. More specifically, the adhesive strength retention after PCT storage was calculated by the following formula.

(8) Drop resistance test Each epoxy resin composition of Examples and Comparative Examples was applied on a copper substrate, a copper block of 10 mm × 10 mm × thickness 10 mm was placed on the coated surface, and the test piece was placed at 80 ° C. It was cured by heating for 1 hour at 120° C. for 1 hour. After curing, the specimens were cooled to room temperature. The obtained test piece was dropped from a height of 100 cm. The drop was repeated 10 times, and the number of drops until the copper block peeled off from the copper substrate was recorded.

Claims (6)

An epoxy resin composition containing the following components (A) to (E).
(A) 100 parts by mass of a non-silicone-modified epoxy resin having two or more epoxy groups per molecule (B) a thiol compound having three or more thiol groups per molecule (C) a silicone-modified epoxy resin 0.5 to 100 parts by mass (D) Microcapsule type curing accelerator 1.0 to 200 parts by mass (E) Reaction inhibitor 0.05 to 10 parts by mass However, the amount of component (B) is the amount of component (A) and the molar equivalent ratio of thiol groups in component (B) to 1 molar equivalent of total epoxy groups in component (C) is 0.1 to 1.0. 2. The epoxy resin composition according to claim 1, wherein component (B) is a thiol compound having 4 or more thiol groups per molecule. 3. The method according to claim 1 or 2, wherein the molar equivalent ratio of thiol groups in component (B) is 0.1 to 0.5 with respect to 1 molar equivalent of total epoxy groups in components (A) and (C). Epoxy resin composition. Component (D) is a microcapsule-type curing accelerator containing at least one selected from the group consisting of phosphorus compounds, tertiary amine compounds, imidazole compounds, urea compounds and amine adduct compounds. Epoxy resin composition according to any one of the items. 5. The epoxy resin composition according to any one of claims 1 to 4, wherein the component (E) is a borate compound and/or a phosphite compound. 6. The epoxy resin composition according to any one of claims 1 to 5, wherein component (D) has a volume average particle size of 0.1 to 10 µm.

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