JP7748615B2 - resin composition - Google Patents

Description

The present invention relates to a resin composition.

Epoxy resin compositions using a thiol compound as a curing agent have good low-temperature curing properties and fast curing properties, and are therefore used in a variety of applications, such as adhesives for assembling electronic devices (see, for example, Patent Document 1).
Electronic devices are becoming smaller, more mobile, and more wearable, and are being used in an ever-more diverse range of environments. As a result, adhesives used in electronic devices are sometimes required to have drop impact resistance and heat shock resistance. To achieve these properties, epoxy resin compositions are required to have a low elastic modulus after curing.

Japanese Patent Application Publication No. 11-256013

However, when an epoxy resin composition containing a thiol compound is designed to have a low elastic modulus after curing, the water absorption rate after curing tends to increase. High water absorption may result in a decrease in adhesiveness due to swelling or deterioration. For example, in the case of electronic device applications, water absorption has a significant impact on reliability.
Therefore, an object of the present invention is to provide a technique that can reduce the elastic modulus of an epoxy resin composition containing a thiol compound without increasing the water absorption rate.

As a result of extensive research, the present inventors have found that the above-mentioned object can be achieved by a resin composition containing (A) an epoxy resin, (B) a thiol compound, (C) a silane coupling agent, and (D) a silicone powder, and have thus completed the present invention.
That is, the present invention includes the following.
[1] A resin composition containing (A) an epoxy resin, (B) a thiol compound, (C) a silane coupling agent, and (D) a silicone powder.
[2] The resin composition according to [1], containing (E) a latent curing accelerator.
[3] The resin composition according to [1] or [2], containing (F) a stabilizer.
[4] The resin composition according to any one of [1] to [3], wherein component (B) includes (B-1) a thiol compound having three or more thiol groups in the molecule, and (B-2) a thiol compound having two thiol groups in the molecule.
[5] The resin composition according to [4], wherein the component (B-1) has a ring skeleton in the molecule.
[6] The resin composition according to [4] or [5], wherein the component (B-1) does not have an ester bond in the molecule.
[7] The resin composition according to any one of [4] to [6], wherein the component (B-2) does not have a ring skeleton in the molecule.
[8] The resin composition according to any one of [4] to [7], wherein the component (B-2) does not have an ester bond in the molecule.
[9] The resin composition according to any one of [5] to [8], wherein the component (B-1) and the component (B-2) do not have a hydroxyl group.
[10] The resin composition according to any one of [1] to [9], wherein component (C) has an epoxy group.
[11] The resin composition according to any one of [1] to 10], containing 1 to 10 mass% of component (C) relative to 100 mass% of the nonvolatile components of the resin composition.
[12] The resin composition according to any one of [1] to 11], containing 5 to 20 mass% of component (D) relative to 100 mass% of the nonvolatile components of the resin composition.
[13] An adhesive comprising the resin composition according to any one of [1] to [12].
[14] An encapsulant comprising the resin composition according to any one of [1] to [12].
[15] A cured product obtained by thermally curing the resin composition according to any one of [1] to [12].
[16] An electronic part comprising the cured product according to [15].

The present invention provides a technology that can reduce the elastic modulus of an epoxy resin composition containing a thiol compound without increasing the water absorption rate.

An embodiment of the present invention will be described below.
The resin composition according to this embodiment contains (A) an epoxy resin, (B) a thiol compound, (C) a silane coupling agent, and (D) a silicone powder.

By adopting the above-described composition, a resin composition is provided that has a low elastic modulus after curing and a low water absorption rate.

The components of the resin composition are described in detail below.

(A) Epoxy Resin The epoxy resin is not particularly limited as long as it has at least one epoxy group in the molecule. Preferably, the epoxy resin has two or more epoxy groups per molecule on average.

Examples of epoxy resins include, but are not limited to, polyglycidyl ethers obtained by reacting epichlorohydrin with polyhydric phenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, and resorcinol, glycerin, and polyhydric alcohols such as polyethylene glycol; glycidyl ether esters obtained by reacting epichlorohydrin with hydroxycarboxylic acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid; polyglycidyl esters obtained by reacting epichlorohydrin with polycarboxylic acids such as phthalic acid and terephthalic acid; epoxidized phenol novolac resins; epoxidized cresol novolac resins; epoxidized polyolefins; cycloaliphatic epoxy resins; and other urethane-modified epoxy resins.

From the viewpoint of maintaining high heat resistance and low moisture permeability, preferred epoxy resins include bisphenol A epoxy resins, bisphenol F epoxy resins, phenol novolac epoxy resins, biphenyl aralkyl epoxy resins, phenol aralkyl epoxy resins, aromatic glycidylamine epoxy resins, and epoxy resins having a dicyclopentadiene structure, with bisphenol A epoxy resins and bisphenol F epoxy resins being more preferred.

The epoxy equivalent of the epoxy resin is, for example, 50 to 1,000 g/eq, preferably 100 to 750 g/eq, and more preferably 150 to 500 g/eq. Here, the epoxy equivalent is the mass of the epoxy resin per epoxy group, and can be measured in accordance with JIS K 7236 (2009).

The epoxy resin may be liquid or solid. Alternatively, both liquid and solid resins may be used. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature. From the viewpoints of coatability, processability, and adhesiveness, it is preferable that at least 10% by mass of the total epoxy resin used be liquid. Specific examples of such liquid epoxy resins include liquid bisphenol A epoxy resins ("jER828EL" and "jER827" manufactured by Mitsubishi Chemical Corporation), liquid bisphenol F epoxy resins ("jER807" manufactured by Mitsubishi Chemical Corporation), naphthalene-type bifunctional epoxy resins ("HP4032" and "HP4032D" manufactured by DIC Corporation), liquid bisphenol A epoxy resin/bisphenol F epoxy resins ("ZX1059" manufactured by Nippon Steel Chemical & Material Co., Ltd.), and hydrogenated epoxy resins ("jERYX8000" manufactured by Mitsubishi Chemical Corporation). Among these, "jER828EL" manufactured by Mitsubishi Chemical Corporation and "jER807" manufactured by Mitsubishi Chemical Corporation are preferred, as they have high heat resistance and low viscosity.
Specific examples of solid epoxy resins include naphthalene-type tetrafunctional epoxy resins ("HP4700" manufactured by DIC Corporation), dicyclopentadiene-type multifunctional epoxy resins ("HP7200" manufactured by DIC Corporation), naphthol-type epoxy resins ("ESN-475V" manufactured by Nippon Steel Chemical & Material Co., Ltd.), epoxy resins having a butadiene structure ("PB-3600" manufactured by Daicel Chemical Industries, Ltd.), and epoxy resins having a biphenyl structure ("NC3000H" and "NC3000L" manufactured by Nippon Kayaku Co., Ltd., and "jERYX4000" manufactured by Mitsubishi Chemical Corporation).

When the non-volatile components of the resin composition are taken as 100% by mass, the epoxy resin content is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, particularly preferably 40% by mass or more, and especially preferably 45% by mass or more. Furthermore, the epoxy resin content is, for example, 95% by mass or less, preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, particularly preferably 75% by mass or less, and especially preferably 70% by mass or less.

In one embodiment, an epoxy resin represented by the following formula (1) or (2) can be used as the epoxy resin.


(In formulas (1) and (2), X, _X1 , and _X2 may be the same or different and are divalent non-aromatic hydrocarbon groups containing four or more —( _CH2 )— groups in the main skeleton; Ar, Ar1, and Ar2 may be the same or different and are divalent aromatic-containing hydrocarbon groups containing a divalent aromatic group in the main skeleton; and n and m each independently represent an integer of 1 to 20.)
Here, the "main skeleton" refers to the skeleton with the longest chain among the skeletons having epoxy groups at both ends.

Preferably, the "divalent non-aromatic hydrocarbon group containing four or more -(CH ₂ )- groups in the main skeleton" for X, X ₁ and X ₂ is
(b1) -O-CH(-CH ₃ )-(O-(CH ₂ ) _p ) _q -O-CH(-CH ₃ )-,
(b2) -(O-(CH ₂ ) _r ) _s -,
(b3)-(O-CH ₂ -CH(-CH ₃ )) _t -,
(b4) -O-CH ₂ -CH(-OH)-CH ₂ -(O-(CH ₂ ) _u ) _v -O-CH ₂ -CH(-OH)-CH ₂ -,
(b5)-(O-(CH ₂ ) _w ) _y -O-CH ₂ -CH(-OH)-, and (b6)-(O-CH ₂ -CH(-CH ₃ ))z-O-CH ₂ -CH(-OH)-
(wherein p, q, r, s, t, u, v, w, y, and z are each independently an integer of 1 to 20).

Furthermore, in the "divalent aromatic-containing hydrocarbon group containing a divalent aromatic group in the main skeleton" of Ar, Ar1, and Ar2, examples of the aromatic group include a phenylene group, a naphthalene group, an anthracene group, and a biphenyl group. The phenylene group may be an ortho-, meta-, or para-phenylene group. The divalent aromatic-containing hydrocarbon group may contain two or more aromatic groups. When two or more aromatic groups are contained, the aromatic groups may be directly bonded to each other, or may be bonded via an alkylene group, an ether bond, an ester bond, an amide bond, or two carbon atoms bonded by a double bond or a triple bond.
Particularly preferred divalent aromatic hydrocarbon groups include structures represented by the following formulas (3) and (4).

In another embodiment, a modified bisphenol-type epoxy resin represented by the following formula (5) can be used as the epoxy resin.

In formula (5), Y is an aliphatic hydrocarbon, Z is _CH2 or C( _CH3 ), and n is in the range of 0 to 10, preferably 1 to 8.
Specific examples of such epoxy resins include YL7175-500 and YL7175-1000 (both manufactured by Japan Epoxy Resins Co., Ltd.).

In a preferred embodiment, two types of epoxy resins (a first epoxy resin and a second epoxy resin) are used as the epoxy resin.

The epoxy equivalent of the first epoxy resin is, for example, 300 to 1000 g/eq, preferably 300 to 700 g/eq, and more preferably 350 to 600 g/eq.
The viscosity of the first epoxy resin at 25° C. (E-type viscometer) is, for example, 5,000 to 50,000 mPa·s, and preferably 10,000 to 30,000 mPa·s.
When the non-volatile components of the resin composition are taken as 100% by mass, the content of the first epoxy resin is, for example, 5 to 40% by mass, preferably 10 to 30% by mass, more preferably 10 to 25% by mass, and even more preferably 10 to 20% by mass.
A specific example of the first epoxy resin is "EXA-4850-150" (manufactured by DIC Corporation, epoxy equivalent: 450 g/eq).

The epoxy equivalent of the second epoxy resin is, for example, 50 to 300 g/eq, preferably 100 to 250 g/eq, and more preferably 100 to 200 g/eq.
The viscosity of the second epoxy resin at 25° C. (E-type viscometer) is, for example, 500 to 5,000 mPa·s, and preferably 1,000 to 3,000 mPa·s.
When the non-volatile components of the resin composition are taken as 100% by mass, the content of the second epoxy resin is, for example, 10 to 60% by mass, preferably 20 to 50% by mass, more preferably 30 to 50% by mass, and even more preferably 30 to 45% by mass.
A specific example of the second epoxy resin is "ZX-1059" (manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent: 165 g/eq).

(B) Thiol Compound The thiol compound is not particularly limited as long as it is a compound that crosslinks or polymerizes epoxy groups. As the thiol compound, those having 2 to 6 (difunctional to hexafunctional) thiol groups per molecule are preferred, and those having 2 to 5 (difunctional to pentafunctional) thiol groups per molecule are more preferred.

For example, thiol compounds include trimethylolpropane tris(3-mercaptopropionate) (abbreviation: TMTP), pentaerythritol tetrakis(3-mercaptopropionate) (abbreviation: PEMP), dipentaerythritol hexakis(3-mercaptopropionate) (abbreviation: DPMP), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (abbreviation: TEMPIC), tris(3-mercaptopropyl)isocyanurate (abbreviation: TMPIC), ethylene glycol bisthioglycolate (abbreviation: EGTG), trimethylolpropane tristhioglycolate (abbreviation: TMTG), and pentaerythritol tetrakisthioglycolate. At least one selected from the group consisting of tetrakis(3-mercaptobutyrate) (abbreviation: PETG), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptobutyrate) (abbreviation: TPMB), trimethylolethane tris(3-mercaptobutyrate) (abbreviation: TEMB), 1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril, and 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene] can be used.

The above thiol compounds can be synthesized using known methods, or commercially available products can be used. Tris(3-mercaptopropyl)isocyanurate (abbreviated as TMPIC) and 4,4'-isopropylidenebis[(3-mercaptopropoxy)benzene] can be synthesized, for example, using the methods described in JP 2012-153794 A and WO 2001/00698 A. Commercially available products include PEMP manufactured by SC Organic Chemicals; OTG, EGTG, TMTG, PETG, 3-MPA, TMTP, and PETP manufactured by Yodo Chemical; TEMP, PEMP, TEMPIC, and DPMP manufactured by Sakai Chemical Industry Co., Ltd.; PE-1 (pentaerythritol tetrakis(3-mercaptobutyrate)), BD-1 (1,4-bis(3-mercaptobutyryloxy)butane), NR-1 (1,3,5-tris(3-mercaptobutyryloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione), TPMB, and TEMB manufactured by Showa Denko; and TS-G (1,3,4,6-tetrakis(2-mercaptoethyl)glycoluril) manufactured by Shikoku Chemicals Corporation.

In a preferred embodiment, a combination of (B-1) a thiol compound having three or more thiol groups in the molecule (hereinafter referred to as a polyfunctional thiol compound) and (B-2) a thiol compound having two thiol groups in the molecule (a bifunctional thiol compound) is used as the thiol compound.

(B-1) Polyfunctional Thiol Compound The polyfunctional thiol compound is not particularly limited as long as it is a compound having three or more thiol groups in the molecule (trifunctional or higher). Preferably, the polyfunctional thiol compound is trifunctional to hexafunctional, more preferably trifunctional to tetrafunctional, and most preferably trifunctional.

The molecular weight of the polyfunctional thiol compound is, for example, 200 to 700, preferably 250 to 500, and more preferably 300 to 400.

The thiol group equivalent (functional group equivalent) of the polyfunctional thiol compound is, for example, 50 to 300 g/eq, preferably 70 to 200 g/eq, and more preferably 80 to 150 g/eq.
The thiol group equivalent is a value indicating the mass of a thiol compound per thiol group, and is a value obtained by dividing the molecular weight of a thiol compound by the number of thiol groups contained in one molecule of the compound.

Preferably, the polyfunctional thiol compound does not have an ester bond within the molecule. In the present invention, an ester bond refers to a bond represented by "-C(=O)O-".

Preferably, the polyfunctional thiol compound does not have a hydroxyl group in the molecule. When there is no hydroxyl group in the molecule, it tends to have a good pot life, making it easier to achieve both long life and rapid curing of the resin composition.

Preferred polyfunctional thiol compounds are compounds having a ring skeleton. The ring skeleton may be any of an alicyclic skeleton, aromatic ring skeleton, heteroaromatic ring skeleton, and heterocyclic skeleton, but is preferably an aromatic ring skeleton, heteroaromatic ring skeleton, or heterocyclic skeleton, and more preferably a heterocyclic skeleton. When a ring skeleton is present, the shear adhesive strength is improved. Examples of compounds having such heterocyclic skeletons include monocyclic or bicyclic compounds with 5- to 8-membered rings and containing at least one nitrogen atom as a ring atom. More specifically, examples of compounds having a heterocyclic skeleton include compounds containing an isocyanuric ring skeleton or a glycoluril skeleton.

For example, a suitable polyfunctional thiol compound is a compound represented by the following formula (6).

In the above formula (6), R ₁ , R ₂ , and R ₃ each independently represent a linear or branched divalent hydrocarbon group having 1 to 6 carbon atoms, preferably 1 to 5 carbon atoms. The hydrocarbon group may further contain one or more divalent groups shown in the following (6a) to (6c):

A specific example of the polyfunctional thiol compound represented by the above formula is tris(3-mercaptopropyl)isocyanurate.

The content of the (B-1) polyfunctional thiol compound in the resin composition is not particularly limited and can be adjusted depending on the type of epoxy resin and the (B-2) bifunctional thiol compound, etc.
For example, when the content of the epoxy resin (A) is taken as 100 parts by mass, the content of the polyfunctional thiol compound (B-1) is preferably 0.1 to 100 parts by mass, more preferably 1 to 60 parts by mass, and even more preferably 10 to 50 parts by mass.
Furthermore, when the sum of the number of thiol groups in the (B-1) polyfunctional thiol compound and the number of thiol groups in the (B-2) bifunctional thiol compound contained in the resin composition is taken as "1," the proportion of the number of thiol groups in the (B-1) polyfunctional thiol compound (total number of thiol groups in component B-1/(total number of thiol groups in component B-1+total number of thiol groups in component B-2)) is, for example, 0.1 to 0.9, preferably 0.2 to 0.8, and more preferably 0.3 to 0.7.
Here, the number of thiol groups refers to the value obtained by dividing the parts by mass of the thiol compound contained in the composition by the thiol group equivalent (parts by mass of thiol/thiol group equivalent). When the composition contains multiple types of thiol compounds as components B-1 and B-2, the number refers to the sum of the values obtained by dividing the parts by mass of each thiol by its corresponding thiol group equivalent.

(B-2) Bifunctional Thiol Compound The bifunctional thiol compound is not particularly limited as long as it is a compound containing two thiol groups in the molecule.

From the viewpoint of suppressing odor, the molecular weight of the bifunctional thiol compound is preferably 130 or more, more preferably 140 or more, even more preferably 150 or more, and most preferably 160 or more.
The molecular weight of the bifunctional thiol compound is, for example, 1,000 or less, preferably 500 or less, more preferably 300 or less, and even more preferably 230 or less, from the viewpoint of obtaining good rapid curing properties.
The molecular weight of the bifunctional thiol compound may be within a range arbitrarily selected from the above upper and lower limits, for example, 130 to 1000, preferably 140 to 500, more preferably 150 to 300, and most preferably 160 to 230.

The thiol group equivalent weight of the bifunctional thiol compound is, for example, 70 to 300 g/eq, preferably 80 to 200 g/eq, and more preferably 85 to 150 g/eq.

Preferably, the bifunctional thiol compound does not have a hydroxyl group in the molecule. When there is no hydroxyl group in the molecule, it tends to have a good pot life, making it easier to achieve both long life and rapid curing of the resin composition.

Preferably, the bifunctional thiol compound does not have an ester bond within the molecule. When an ester bond is not contained, hydrolysis based on the ester bond does not occur, thereby improving moisture resistance and further increasing reliability.

Preferably, the bifunctional thiol compound does not have a ring skeleton within the molecule. If the compound does not have a ring skeleton, the skeleton becomes flexible, and a resin composition with superior peel strength can be obtained.

A suitable bifunctional thiol compound is a compound represented by the following formula (7).
Formula (7): HS-R ₄ -SH
In formula (7), _R4 represents a straight-chain or branched-chain divalent hydrocarbon group having 3 to 16 carbon atoms, preferably 4 to 12 carbon atoms. The hydrocarbon group may contain one or more of the divalent groups shown in (7a) to (7c) below. _R4 is preferably a straight-chain hydrocarbon group or a straight-chain hydrocarbon group containing one or more divalent groups shown in (7a) below.

Specific examples of bifunctional thiol compounds represented by the above formula (7) include 1,4-butanedithiol, 1,6-hexaneedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 3,6-dioxa-1,8-octanedithiol, and bis-2-mercaptoethyl sulfide, with 1,8-octanedithiol, 1,10-decanedithiol, and 3,6-dioxa-1,8-octanedithiol being preferred.

The content of the (B-2) bifunctional thiol compound in the resin composition is not particularly limited. For example, when the content of the (A) epoxy resin is taken as 100 parts by mass, the content of the (B-2) bifunctional thiol compound is preferably 0.1 to 100 parts by mass, more preferably 1 to 60 parts by mass, and even more preferably 5 to 30 parts by mass.

Furthermore, in the resin composition according to the present embodiment, the ratio of the "total number of thiol groups in component B" to the "number of epoxy groups in component A" (total number of thiol groups in component B/total number of epoxy groups in component A) is preferably 0.2 to 2.0, and more preferably 0.6 to 1.2.
Here, the number of epoxy groups refers to the value obtained by dividing the parts by mass of the epoxy resin contained in the composition by the epoxy group equivalent (parts by mass of epoxy groups/epoxy group equivalent). When multiple types of epoxy resins as component A are contained in the composition, the number of epoxy groups refers to the sum of the values obtained by dividing the parts by mass of each epoxy resin by its respective epoxy group equivalent.

(C) Silane coupling agent The silane coupling agent used in this embodiment is not particularly limited.As the silane coupling agent, for example, alkoxysilane compound, aminosilane coupling agent, epoxysilane coupling agent, methacrylsilane coupling agent, vinylsilane coupling agent, styrylsilane coupling agent, acrylicsilane coupling agent, isocyanurate silane coupling agent, ureido silane coupling agent, mercaptosilane coupling agent, and isocyanate silane coupling agent can be selected from the silane coupling agent.Among them, silane coupling agent selected from the group consisting of aminosilane coupling agent, epoxysilane coupling agent, and methacrylsilane coupling agent is preferred.Silane coupling agent may be used alone, or two or more may be used in combination.

The alkoxysilane compound means a silane compound represented by R _a SiX _4-a (wherein R represents (i) a hydrogen atom; (ii) an alkyl group which may have a substituent selected from an alkoxy group and a halogen atom; and (iii) an aryl group which may have a substituent selected from an alkyl group, an alkoxy group, and a halogen atom, X represents an alkoxy group, and a represents an integer of 0 to 3), and examples thereof include methyltrimethoxysilane (e.g., "KBM-13" manufactured by Shin-Etsu Chemical Co., Ltd.), dimethyldimethoxysilane (e.g., "KBM-22" manufactured by Shin-Etsu Chemical Co., Ltd.), phenyltrimethoxysilane (e.g., "KBM103" manufactured by Shin-Etsu Chemical Co., Ltd.), methyltriethoxysilane (e.g., "KBE-13" manufactured by Shin-Etsu Chemical Co., Ltd.), dimethyldiethoxysilane (e.g., "KBE-22" manufactured by Shin-Etsu Chemical Co., Ltd.), phenyltriethoxysilane (e.g., "KBE-22" manufactured by Shin-Etsu Chemical Co., Ltd.), and phenyltriethoxysilane (e.g., "KBE-22" manufactured by Shin-Etsu Chemical Co., Ltd.). "KBE-103" manufactured by Shin-Etsu Chemical Co., Ltd.), n-propyltrimethoxysilane (for example, "KBM-3033" manufactured by Shin-Etsu Chemical Co., Ltd.), n-propyltriethoxysilane (for example, "KBE-3033" manufactured by Shin-Etsu Chemical Co., Ltd.), hexyltrimethoxysilane (for example, "KBM-3063" manufactured by Shin-Etsu Chemical Co., Ltd.), hexyltriethoxysilane (for example, "KBE-3063" manufactured by Shin-Etsu Chemical Co., Ltd.), octyltrimethoxysilane (for example, "KBM-3063" manufactured by Shin-Etsu Chemical Co., Ltd.), octyltriethoxysilane (for example, "KBE ... Examples of such silane include tiltriethoxysilane (e.g., "KBE-3083" manufactured by Shin-Etsu Chemical Co., Ltd.), decyltrimethoxysilane (e.g., "KBM-3103C" manufactured by Shin-Etsu Chemical Co., Ltd.), 1,6-bis(trimethoxysilyl)hexane (e.g., "KBM-3066" manufactured by Shin-Etsu Chemical Co., Ltd.), and 3,3,3-trifluoropropyltrimethoxysilane (e.g., "KBM-7103" manufactured by Shin-Etsu Chemical Co., Ltd.).

Aminosilane coupling agents refer to alkoxysilane compounds having an amino group, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (e.g., "KBM-602" manufactured by Shin-Etsu Chemical Co., Ltd.), N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (e.g., "KBM-603" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-aminopropyltrimethoxysilane (e.g., "KBM-903" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-aminopropyltriethoxysilane (e.g., "KBM-903" manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-aminopropyltriethoxysilane. Examples include silane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBE-903"), 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBE-9103"), N-phenyl-3-aminopropyltrimethoxysilane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBM-573"), and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBM-575").

The term "epoxysilane coupling agent" refers to a silane compound having an epoxy group, preferably an alkoxysilane compound having an epoxy group. Examples of epoxysilane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (e.g., "KBM-303" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropylmethyldimethoxysilane (e.g., "KBM-402" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyltrimethoxysilane (e.g., "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-glycidoxypropylmethyldiethoxysilane (e.g., "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of suitable silane coupling agents include "KBE-402" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-glycidoxypropyltriethoxysilane (for example, "KBE-403" manufactured by Shin-Etsu Chemical Co., Ltd.), 8-glycidoxyoctyltrimethoxysilane (for example, "KBM-4083" manufactured by Shin-Etsu Chemical Co., Ltd.), epoxy-modified alkoxy oligomer silane coupling agents (for example, "KR-517" manufactured by Shin-Etsu Chemical Co., Ltd.), and glycidoxyoctyltrimethoxysilane (for example, "KBM-4803" manufactured by Shin-Etsu Chemical Co., Ltd.).

Methacrylsilane coupling agents refer to alkoxysilane compounds containing a methacryloyl group, and examples include 3-methacryloxypropylmethyldimethoxysilane (e.g., "KBM-502" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropyltrimethoxysilane (e.g., "KBM-503" manufactured by Shin-Etsu Chemical Co., Ltd.), 3-methacryloxypropylmethyldiethoxysilane (e.g., "KBE-502" manufactured by Shin-Etsu Chemical Co., Ltd.), and 3-methacryloxypropyltriethoxysilane (e.g., "KBE-503" manufactured by Shin-Etsu Chemical Co., Ltd.).

Vinylsilane coupling agents refer to alkoxysilane compounds containing a vinyl group, such as vinyltrimethoxysilane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBM-1003") and vinyltriethoxysilane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBE-1003"). Styrylsilane coupling agents refer to alkoxysilane compounds containing a styryl group, such as p-styryltrimethoxysilane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBM-1403"). Acrylicsilane coupling agents refer to alkoxysilane compounds containing an acryloyl group, such as 3-acryloxypropyltrimethoxysilane (e.g., Shin-Etsu Chemical Co., Ltd.'s "KBM-5103").

Isocyanurate silane coupling agents refer to alkoxysilane compounds with an isocyanurate structure, such as tris-(trimethoxysilylpropyl)isocyanurate (e.g., "KBM-9659" manufactured by Shin-Etsu Chemical Co., Ltd.). Ureido silane coupling agents refer to alkoxysilane compounds with a ureido group, such as 3-ureidopropyltrialkoxysilane (e.g., "KBE-585" manufactured by Shin-Etsu Chemical Co., Ltd.). Mercapto silane coupling agents refer to alkoxysilane compounds with a mercapto group, such as 3-mercaptopropylmethyldimethoxysilane (e.g., "KBM-802" manufactured by Shin-Etsu Chemical Co., Ltd.) and 3-mercaptopropyltrimethoxysilane (e.g., "KBM-803" manufactured by Shin-Etsu Chemical Co., Ltd.). An isocyanate-based silane coupling agent refers to an alkoxysilane compound having an isocyanate structure, such as 3-isocyanatepropyltriethoxysilane (e.g., "KBE-9007N" manufactured by Shin-Etsu Chemical Co., Ltd.).

Among the above, epoxy silane coupling agents are preferred. More preferred epoxy silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and oligomeric coupling agents having an alkoxysilyl group and an epoxy group.

The content of the silane coupling agent is, for example, 1 to 10% by mass, preferably 2 to 8% by mass, and more preferably 4 to 6% by mass, based on 100% by mass of the non-volatile components of the resin composition.

(D) Silicone Powder Silicone powder refers to a powdered silicone compound.
Examples of silicone powder include silicone rubber powder, silicone resin powder, and silicone composite powder.
Silicone rubber powder is a powder of a compound in which linear molecules (for example, linear organopolysiloxane) are crosslinked.
Silicone resin powder is a powder of a silicone compound having a three-dimensional network-like crosslinked structure. Specific examples include finely cured polyorganosilsesquioxane powders having a three-dimensional network-like crosslinked structure in which siloxane bonds are represented by (RSiO _3/2 ) _n (R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is 1 to 18).
The silicone composite powder is a powder having a structure in which the particle surfaces of silicone rubber powder are coated with silicone resin.
Preferably, a silicone composite powder is used as the silicone powder.

The average particle size of the silicone powder is, for example, 0.05 μm or more, preferably 0.1 μm or more, and more preferably 0.5 μm or more. The average particle size of the silicone powder is, for example, 100 μm or less, preferably 50 μm or less, and more preferably 30 μm or less.

The content of silicone powder is, for example, 5 to 25% by mass, preferably 5 to 20% by mass, and more preferably 5 to 15% by mass, based on 100% by mass of the non-volatile components of the resin composition.

Specific examples of silicone powders include KMP-600 (manufactured by Shin-Etsu Chemical Co., Ltd.), KMP-601 (manufactured by Shin-Etsu Chemical Co., Ltd.), KMP-602 (manufactured by Shin-Etsu Chemical Co., Ltd.), KMP-605 (manufactured by Shin-Etsu Chemical Co., Ltd.), and X-52-7030 (manufactured by Shin-Etsu Chemical Co., Ltd.).

(E) Latent Curing Accelerator Preferably, the resin composition according to this embodiment contains a latent curing accelerator. A latent curing accelerator is an additive that does not contribute to the curing of the epoxy resin at room temperature (20°C ± 15°C (JIS Z8703)) but has the function of accelerating the curing of the epoxy resin when heated.

Preferably, a solid-dispersion-type latent curing accelerator is used as the latent curing accelerator. A solid-dispersion-type latent curing accelerator is a compound that is a solid that is insoluble in epoxy resins at room temperature, but is solubilized by heating and functions as a curing accelerator for epoxy resins.
Examples of solid-dispersed latent curing accelerators include, but are not limited to, imidazole compounds that are solid at room temperature and solid-dispersed amine adduct latent curing accelerators. Of these, solid-dispersed amine adduct latent curing accelerators are preferred.

Examples of the imidazole compounds that are solid at room temperature include 2-heptadecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4-benzyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2-methylimidazolyl-(1))-ethyl-S-triazine, and 2,4-diamino-6-(2'-methylimidazolyl-(1)')-ethyl-S-triazine. Examples of imidazole-isocyanuric acid adducts include 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, N-(2-methylimidazolyl-1-ethyl)-urea, and N,N'-(2-methylimidazolyl-(1)-ethyl)-adiboyldiamide, but are not limited to these.

Examples of solid-dispersion amine adduct latent curing accelerators include reaction products of amine compounds and epoxy compounds (amine-epoxy adducts), and reaction products of amine compounds and isocyanate compounds or urea compounds (urea adducts).

Examples of epoxy compounds used as raw materials for producing the solid dispersion-type amine adduct latent curing accelerator (amine-epoxy adduct) include polyglycidyl ethers obtained by reacting epichlorohydrin with polyhydric phenols such as bisphenol A, bisphenol F, catechol, and resorcinol, or polyhydric alcohols such as glycerin and polyethylene glycol; glycidyl ether esters obtained by reacting epichlorohydrin with hydroxycarboxylic acids such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid; phthalic acid, tetrahydrofuran, and the like. Examples include, but are not limited to, polyglycidyl esters obtained by reacting polycarboxylic acids such as benzoic acid with epichlorohydrin; glycidylamine compounds obtained by reacting 4,4'-diaminodiphenylmethane or m-aminophenol with epichlorohydrin; polyfunctional epoxy compounds such as epoxidized phenol novolac resin, epoxidized cresol novolac resin, and epoxidized polyolefin; and monofunctional epoxy compounds such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate.

The amine compound used as a raw material for producing the solid dispersion-type amine adduct latent curing accelerator may be any compound that contains one or more active hydrogen atoms in the molecule capable of addition reacting with epoxy groups and at least one functional group selected from primary amino groups, secondary amino groups, and tertiary amino groups. Examples of such amine compounds include, but are not limited to, aliphatic amines such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4'-diamino-dicyclohexylmethane; aromatic amine compounds such as 4,4'-diaminodiphenylmethane and 2-methylaniline; and nitrogen-containing heterocyclic compounds such as 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, and piperazine.

Among these, compounds having a tertiary amino group in the molecule are particularly useful as raw materials for producing latent curing accelerators with excellent curing acceleration capabilities. Examples of such compounds include amine compounds such as dimethylaminopropylamine, diethylaminopropylamine, di-n-propylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, and N-methylpiperazine, as well as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, and 2-phenylimidazole. primary or secondary amines having a tertiary amino group in the molecule, such as imidazole compounds such as nylimidazole; 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1-butoxymethyl-2-dimethylaminoethanol, 1-(2-hydroxy-3-phenoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-ethyl-4-methylimidazole, 1- (2-hydroxy-3-butoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-butoxypropyl)-2-ethyl-4-methylimidazole, 1-(2-hydroxy-3-phenoxypropyl)-2-phenylimidazoline, 1-(2-hydroxy-3-butoxypropyl)-2-methylimidazoline, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, N-β-hydroxyethylmorpholine, 2-dimethylaminoethanethiol, 2-mercaptopropyl Examples include alcohols, phenols, thiols, carboxylic acids, and hydrazides having a tertiary amino group in the molecule, such as lysine, 2-benzimidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 4-mercaptopyridine, N,N-dimethylaminobenzoic acid, N,N-dimethylglycine, nicotinic acid, isonicotinic acid, picolinic acid, N,N-dimethylglycine hydrazide, N,N-dimethylpropionic acid hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide; and the like.

When producing the latent curing accelerator by addition reaction of the epoxy compound and amine compound, an active hydrogen compound having two or more active hydrogen atoms in the molecule can also be added. Examples of such active hydrogen compounds include, but are not limited to, polyhydric phenols such as bisphenol A, bisphenol F, bisphenol S, hydroquinone, catechol, resorcinol, pyrogallol, and phenol novolac resin; polyhydric alcohols such as trimethylolpropane; polycarboxylic acids such as adipic acid and phthalic acid; 1,2-dimercaptoethane, 2-mercaptoethanol, 1-mercapto-3-phenoxy-2-propanol, mercaptoacetic acid, anthranilic acid, and lactic acid.

Examples of isocyanate compounds that can be used as raw materials for producing the solid-dispersion amine adduct latent curing accelerator include monofunctional isocyanate compounds such as n-butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, and benzyl isocyanate; polyfunctional isocyanate compounds such as hexamethylene diisocyanate, toluylene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and bicycloheptane triisocyanate; and terminal isocyanate group-containing compounds obtained by reacting these polyfunctional isocyanate compounds with active hydrogen compounds. Examples of such compounds containing terminal isocyanate groups include, but are not limited to, an adduct having a terminal isocyanate group obtained by reacting toluylene diisocyanate with trimethylolpropane, and an adduct having a terminal isocyanate group obtained by reacting toluylene diisocyanate with pentaerythritol.

Urea compounds used as raw materials for producing the solid dispersion-type amine adduct latent curing accelerator include, but are not limited to, urea and thiourea.

Solid-dispersion latent curing accelerators can be easily obtained, for example, by appropriately mixing the above-mentioned manufacturing raw materials, reacting them at a temperature between room temperature and 200°C, cooling them to solidify, and then pulverizing them; or by reacting them in a solvent such as methyl ethyl ketone, dioxane, or tetrahydrofuran, removing the solvent, and then pulverizing the solid content.

Typical examples of commercially available solid dispersion-type latent curing accelerators include, for example, amine-epoxy adducts (amine adducts), such as "Amicure PN-F" (product name, manufactured by Ajinomoto Fine-Techno Co., Ltd.), "Amicure PN-23" (product name, manufactured by Ajinomoto Fine-Techno Co., Ltd.), "Amicure PN-H" (product name, manufactured by Ajinomoto Fine-Techno Co., Ltd.), "Novacure HX-3742" (product name, manufactured by Asahi Kasei Corporation), and "Novacure HX-3721" (product name, manufactured by Asahi Kasei Corporation), and urea-type adducts, such as "Fujicure FXR-1020" (product name, manufactured by Fuji Kasei Co., Ltd.) and "Fujicure FXR-1030" (product name, manufactured by Fuji Kasei Co., Ltd.), but are not limited to these.

When the content of the epoxy resin (Component A) is taken as 100 parts by mass, the content of the latent curing accelerator (Component E) is preferably 0.1 to 100 parts by mass, more preferably 1 to 60 parts by mass, and even more preferably 5 to 30 parts by mass.

(F) Stabilizer The resin composition according to this embodiment preferably further contains one or more stabilizers (component F) selected from borate ester compounds, titanate ester compounds, aluminate compounds, zirconate compounds, isocyanate compounds, carboxylic acids, acid anhydrides, and mercapto organic acids in order to achieve excellent storage stability.

Examples of the boric acid ester compounds include trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, triallyl borate, trihexyl borate, tricyclohexyl borate, trioctyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, tris(2-ethylhexyloxy)borane, bis(1,4,7,10-tetraoxaundecyl)(1,4,7,10,13-pentaoxatetradecyl)(1,4,7-trioxaundecyl)borane, tribenzyl borate, triphenyl borate, tri-o-tolyl borate, tri-m-tolyl borate, and triethanolamine borate.

Examples of the titanate ester compound include tetraethyl titanate, tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, and tetraoctyl titanate.

Examples of the aluminate compound include triethyl aluminate, tripropyl aluminate, triisopropyl aluminate, tributyl aluminate, and trioctyl aluminate.

Examples of the zirconate compound include tetraethyl zirconate, tetrapropyl zirconate, tetraisopropyl zirconate, and tetrabutyl zirconate.

Examples of the isocyanate compound include n-butyl isocyanate, isopropyl isocyanate, 2-chloroethyl isocyanate, phenyl isocyanate, p-chlorophenyl isocyanate, benzyl isocyanate, hexamethylene diisocyanate, 2-ethylphenyl isocyanate, 2,6-dimethylphenyl isocyanate, 2,4-toluene diisocyanate, toluylene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, diphenylmethane-4,4'-diisocyanate, tolidine diisocyanate, isophorone diisocyanate, xylylene diisocyanate, paraphenylene diisocyanate, and bicycloheptane triisocyanate.

Examples of the carboxylic acid include saturated aliphatic monobasic acids such as formic acid, acetic acid, propionic acid, butyric acid, caproic acid, and caprylic acid; unsaturated aliphatic monobasic acids such as acrylic acid, methacrylic acid, and crotonic acid; halogenated fatty acids such as monochloroacetic acid and dichloroacetic acid; monobasic oxyacids such as glycolic acid and lactic acid; aliphatic aldehyde acids and ketone acids such as glyoxalic acid and acetic acid; aliphatic polybasic acids such as oxalic acid, malonic acid, succinic acid, and maleic acid; aromatic monobasic acids such as benzoic acid, halogenated benzoic acids, toluic acid, phenylacetic acid, cinnamic acid, and mandelic acid; and aromatic polybasic acids such as phthalic acid and trimesic acid.

Examples of the acid anhydride include aliphatic or aliphatic polybasic acid anhydrides such as succinic anhydride, dodecynylsuccinic anhydride, maleic anhydride, an adduct of methylcyclopentadiene and maleic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride, and aromatic polybasic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyrrolimellitic anhydride.

Examples of the mercapto organic acid include mercapto aliphatic monocarboxylic acids such as mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, mercaptosuccinic acid, and dimercaptosuccinic acid; mercapto aliphatic monocarboxylic acids obtained by the esterification reaction of a hydroxy organic acid with a mercapto organic acid; and mercapto aromatic monocarboxylic acids such as mercaptobenzoic acid.

Of these, boric acid ester compounds are preferred as component F from the standpoint of versatility, safety, and improved storage stability, with triethyl borate, tri-n-propyl borate, triisopropyl borate, and tri-n-butyl borate being more preferred, and triethyl borate being even more preferred. There are no particular restrictions on the content of component F as long as it improves the storage stability of the resin, but, assuming that the content of the epoxy resin in component A is 100 parts by mass, the content of component F is preferably 0.001 to 50 parts by mass, more preferably 0.05 to 30 parts by mass, and even more preferably 0.1 to 10 parts by mass.

In terms of blending component F into the resin composition, it can be blended simultaneously with components A through E, or it can be premixed with the latent curing accelerator for component E. Mixing can be done by contacting the two in a solvent such as methyl ethyl ketone or toluene, in a liquid epoxy resin, or without a solvent.

(G) Other Components Various additives commonly used in the field of the present invention, such as fillers (e.g., fumed silica), diluents, solvents, pigments, flexibility-imparting agents, coupling agents, antioxidants, thixotropy-imparting agents, and dispersants, can be added to the resin composition of this embodiment as needed.

Preparing the resin composition of this embodiment using the above-described components A to D and optional components E to G as raw materials is not particularly difficult and can be done in accordance with conventionally known methods. For example, the resin composition can be prepared by mixing the components in a mixer such as a Henschel mixer.

The resin composition according to this embodiment can be provided and used as a one-component resin composition. That is, the resin composition can be cured by applying heat or the like after coating. Heating is suitably performed at a temperature of, for example, 70 to 150°C, preferably 75 to 120°C, more preferably 80 to 100°C, for, for example, 1 to 60 minutes, preferably 3 to 45 minutes.
The resin composition is preferably used as an adhesive for assembling electronic components.

This embodiment also includes a cured resin obtained by heating the above-described resin composition, as well as functional products containing the cured resin. Examples of functional products include adhesives, casting agents, sealants, sealing agents, fiber-reinforced resins, coating agents, and paints.

The present invention will be explained in more detail below based on examples, but the present invention is not limited to the following examples.

[Preparation of Resin Composition]
Resin compositions according to Examples 1 to 5 and Comparative Examples 1 and 2 were prepared by mixing the components according to the formulation shown in Table 1. The amount of each component in Table 1 is in parts by mass. The "thiol/epoxy" column in Table 1 indicates the number of thiol groups/the number of epoxy groups.
Table 2 also shows the amount (parts by mass) of each component when the non-volatile components of the resin composition are taken as 100 parts by mass.
Table 3 shows the blending amount (parts by mass) of each component when the epoxy resin is taken as 100 parts by mass.

Specifically, the amounts of epoxy resin, filler, and silicone powder shown in Table 1 were weighed into dedicated plastic containers. These were then thoroughly mixed using a planetary centrifugal mixer (Thinky Corporation; ARE-310) at 2000 rpm for approximately 30 seconds to 1 minute at room temperature of 25°C, and then uniformly dispersed by kneading with a three-roll mill to obtain a roll dispersion. The silane coupling agent, storage stabilizer, curing accelerator, and thiol compound were added to the roll dispersion, and the mixture was thoroughly mixed using a planetary centrifugal mixer at 2000 rpm for approximately 30 seconds to 1 minute at room temperature of 25°C. Finally, the mixture was degassed under vacuum (pressure set to 0) at 900 rpm for 2 minutes using a Kyoritsu Seiki HM-200W automatic planetary centrifugal mixer to obtain the desired resin composition.

The details of the materials used are as follows:
[Component A epoxy resin]
EXA-4850-150: manufactured by DIC Corporation, epoxy equivalent weight 450 g/eq, viscosity 15,000 (25°C, E-type viscometer, mPa·S), molecular weight 900
ZX-1059: Bisphenol A type (BPA type) / bisphenol F type (BPF type) epoxy resin, epoxy equivalent 165 g/eq, viscosity 1,900 to 2,600 (mPa s)

[Component B, thiol]
TMPIC: Ajinomoto Fine-Techno Co., Inc., tris(3-mercaptopropyl) isocyanurate, thiol functional group equivalent 117 g/eq

MR-93: 3,6-dioxa-1,8-octanedithiol, manufactured by Daito Sangyo Co., Ltd., thiol functional group equivalent: 91 g/eq

BD-1: 1,4-bis(3-mercatobutyryloxy)butane, manufactured by Showa Denko K.K., thiol functional group equivalent: 147 g/eq

[Component C Modified Silane Coupling Agent]
KR-517: Epoxy-modified alkoxy oligomer silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd. KBM-4803: Glycidoxyoctyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd.

[Component D: Silicone powder]
KMP-601: Silicone composite powder, average particle size 12 μm, manufactured by Shin-Etsu Chemical Co., Ltd.
KMP-605: Silicone composite powder, average particle size 2 μm, manufactured by Shin-Etsu Chemical Co., Ltd.

[Component E: Curing accelerator]
PN-F: Ajinomoto Fine-Techno Co., Ltd., amine epoxy adduct curing agent

[Component F: Storage stability improver]
TEB: Triethyl borate, manufactured by Tokyo Chemical Industry Co., Ltd.

[Inorganic filler]
AEROSIL200: fumed silica manufactured by Nippon Aerosil Co., Ltd.

[Evaluation of Elastic Modulus]
Each resin composition obtained in the examples and comparative examples was applied to a release PET film (NS-80A, manufactured by Toray Industries, Inc.) using a bar coater, and each was heated at 80°C for 30 minutes to obtain a cured product. The obtained cured product having a thickness of 100 μm was punched out using a dumbbell (product name "Super Dumbbell Cutter (Model: SDMK-5889-01)", manufactured by Dumbbell Co., Ltd.) to prepare a test piece for measuring tensile strength. The PET film was peeled off from the test piece. A tensile test was performed using a Tensilon universal testing machine (manufactured by Orientec Co., Ltd., RTM-500) under conditions of a temperature of 25°C, humidity of 50%, and a tensile speed of 5 mm/min, and the elastic modulus (MPa) was measured.

[Evaluation of water absorption rate]
2.8 ml of each resin composition obtained in the Examples and Comparative Examples was weighed into an aluminum container 4 cm in diameter and 6 mm in height, and heated at 60°C for 4 hours to obtain a cured product 4 cm in diameter and 2 mm in thickness. The weight of the resulting cured product was measured using a precision balance ("XS-205" manufactured by METTLER TOLEDO) and placed in boiling water and boiled for 1 hour. After 1 hour, the cured product was removed, the surface moisture was removed, and the weight was measured using a precision balance. The water absorption (%) was calculated as follows:
[Water absorption rate] = [[Weight after test] - [Initial weight]] x 100 / [Initial weight]

[Discussion of evaluation results]
The results of the above evaluations are shown in Table 1.

Comparing Comparative Example 1 and Comparative Example 2, Comparative Example 1 has a lower elastic modulus and a higher water absorption rate. This shows that using silicone powder in an epoxy resin composition containing a thiol compound can reduce the elastic modulus, but increases the water absorption rate.

In contrast, Examples 1 to 5 have a lower elastic modulus than Comparative Examples 1 and 2. Furthermore, the water absorption of Examples 1 to 5 is not increased compared to Comparative Example 2. In other words, it was found that the elastic modulus can be reduced without increasing the water absorption by using a silane coupling agent in addition to silicone powder.

Claims (14)

A resin composition comprising: (A) an epoxy resin having an epoxy equivalent of 50 to 1000 g/eq; (B) a thiol compound; (C) a silane coupling agent; and (D) a silicone powder,
Component (B) contains (B-1) a thiol compound having three or more thiol groups in the molecule and (B-2) a thiol compound having two thiol groups in the molecule,
Component (B-1) does not have an ester bond in the molecule,
The resin composition contains 30% by mass or more of component (A) relative to 100% by mass of the non-volatile components,
The resin composition contains 4 to 10% by mass of component (C) relative to 100% by mass of the nonvolatile components,
A resin composition comprising more than 5% by mass and not more than 25% by mass of component (D) relative to 100% by mass of the nonvolatile components of the resin composition. The resin composition according to claim 1, containing (E) a latent curing accelerator. The resin composition according to claim 1 or 2, containing (F) a stabilizer. The resin composition according to any one of claims 1 to 3, wherein component (B-1) has a ring skeleton within the molecule. The resin composition according to any one of claims 1 to 4, wherein component (B-2) does not have a ring structure within the molecule. The resin composition according to any one of claims 1 to 5, wherein component (B-2) does not have an ester bond in the molecule. The resin composition according to any one of claims 4 to 6, wherein component (B-1) and component (B-2) do not have a hydroxyl group. The resin composition according to any one of claims 1 to 7, wherein component (C) has an epoxy group. 9. The resin composition according to claim 1, comprising 4 to 8 mass% of component (C) relative to 100 mass% of the nonvolatile components of the resin composition. The resin composition according to any one of claims 1 to 9, comprising more than 5% by mass and no more than 20% by mass of component (D) relative to 100% by mass of the non-volatile components of the resin composition. An adhesive containing the resin composition described in any one of claims 1 to 10. An encapsulant containing the resin composition described in any one of claims 1 to 10. A cured product obtained by thermally curing the resin composition described in any one of claims 1 to 10. An electronic component comprising the cured product described in claim 13.