JP2022014023A - One-pack epoxy resin composition - Google Patents

Abstract

To provide a one-pack epoxy resin composition that contains flexible epoxy resin and has both of low-temperature curability and flexibility.SOLUTION: A one-pack epoxy resin composition contains (A) flexible epoxy resin, (B) thiol compounds (at least including the thiol compound represented by the formula (1)), and (C) a latent curing agent (where Z is a sulfur atom or an oxygen atom, n1 and n2 independently represent 2 or 3).SELECTED DRAWING: None

Description

The present invention relates to a one-pack epoxy resin composition comprising a flexible epoxy resin, a specific thiol compound and a curing agent.

Conventionally, epoxy resins have excellent performance in terms of mechanical properties, electrical properties, thermal properties, chemical resistance, adhesiveness, etc., and therefore paints, insulating materials for electrical and electronic use, and adhesives. It is used for a wide range of purposes such as.

While the composition using the epoxy resin has the above-mentioned characteristics, the cured product has a drawback that it is poorly flexible and very brittle. This means that the cured product is destroyed by some strain, which is very problematic in various applications. For example, when an epoxy resin composition is used for bonding or sealing automobiles, home appliances, and other electrical parts, if the cured product is brittle, cracks will occur due to mechanical vibration and expansion and contraction due to heat, and corrosion and performance of metal parts will occur. It causes a decrease and is not preferable. As a means for solving such a problem, for example, by using an epoxy resin (so-called flexible epoxy resin) that can exhibit flexibility (flexibility) at the time of curing, flexibility is imparted to the cured product and brittleness is improved. The method is known (for example, Patent Documents 1 to 3).

Further, in recent years, there is an increasing demand for low-temperature curability of a one-component epoxy resin composition in order to bond or seal a member having low heat resistance using a one-component epoxy resin composition, and the low-temperature curability is increasing. It is known that it is effective to use a thiol compound having a specific structure for expression (Patent Document 4).

Japanese Unexamined Patent Publication No. 63-265915 Japanese Unexamined Patent Publication No. 2004-156024 Japanese Unexamined Patent Publication No. 2007-23134 International Publication WO2018 / 079466 Pamphlet

The present inventors prepared a one-component epoxy resin composition containing a flexible epoxy resin with reference to the above-mentioned Patent Documents 1 to 3, and cured the one-component epoxy resin composition at a low temperature. As shown in the example, it was found that it did not cure in a short time. Therefore, it was found that when the thiol compound (glycoluryl derivative) described in Patent Document 4 was used, the low-temperature curability was improved, but the flexibility of the obtained cured product was significantly reduced.

An object of the present invention is to provide a one-component epoxy resin composition containing a flexible epoxy resin, which has both low-temperature curability and flexibility.

As a result of studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by a one-component epoxy resin composition containing a flexible epoxy resin, a specific thiol compound and a latent curing agent. rice field. Specifically, the present invention includes the following inventions.

[1]
A one-component epoxy resin composition containing the following (A) to (C).
(A) Flexible epoxy resin (B) Thiol compound (However, at least a thiol compound represented by the following formula (1) is included).

（式中、Ｚは硫黄原子又は酸素原子であり、ｎ^１及びｎ^２はそれぞれ独立に２又は３である。）
（Ｃ）潜在性硬化剤

(In the formula, Z is a sulfur atom or an oxygen atom, and n ¹ and n ² are 2 or 3 independently, respectively.)
(C) Latent curing agent

[2]
The one-component epoxy resin composition according to [1], further comprising an epoxy resin other than (A).

[3]
The one-component epoxy resin composition according to [2], wherein the epoxy resin other than the above (A) is a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin.

[4]
A cured product obtained by curing the one-component epoxy resin composition according to any one of [1] to [3].

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a one-component epoxy resin composition containing a flexible epoxy resin, which has excellent adhesive strength even when cured at a low temperature while having both low-temperature curability and flexibility. can. In particular, if a thiol compound represented by the above formula (1) is contained, flexibility is exhibited even when other thiol compounds are used in combination. Therefore, an epoxy resin composition having various characteristics when used in combination with other thiol compounds. It is also possible to provide goods.

The one-component epoxy resin composition of the present invention comprises (A) a flexible epoxy resin and (B) a thiol compound [however, at least the following formula (1):

（式中、Ｚは硫黄原子又は酸素原子であり、ｎ^１及びｎ^２はそれぞれ独立に２又は３である。）
で表される化合物を含む。］及び（Ｃ）潜在性硬化剤を含有する。以下、本発明の一液型エポキシ樹脂組成物について詳述する。

(In the formula, Z is a sulfur atom or an oxygen atom, and n ¹ and n ² are 2 or 3 independently, respectively.)
Includes compounds represented by. ] And (C) contain a latent curing agent. Hereinafter, the one-component epoxy resin composition of the present invention will be described in detail.

[(A) Flexible epoxy resin]
The flexible epoxy resin used in the present invention is an epoxy resin that exhibits flexibility when cured, and examples thereof include the epoxy resins described in Patent Documents 1 to 3. As a specific structure of the flexible epoxy resin, for example, (a) two or more glycidyloxy groups and (b) _two or more -CH 2-- are contained in the main skeleton as a divalent non-aromatic hydrocarbon group. , And (c) an epoxy compound containing a divalent aromatic-containing hydrocarbon group containing a divalent aromatic group in the main skeleton, or a polymer thereof. The main skeleton is the skeleton having the longest chain among the skeletons having two or more glycidyloxy groups at both ends in (a). Hereinafter, the above (b) and (c) will be described in detail.

(B) Divalent non-aromatic hydrocarbon group containing 2 or more -CH _2- in the main skeleton In the divalent non-aromatic hydrocarbon group, the number of -CH _2- contained in the main skeleton is 2 or more. Is preferable, more preferably 3 or more, still more preferably 4 or more, particularly preferably 5 to 30, and particularly preferably 6 to 20. The two or more -CH _2- may be directly bonded, an ether bond, an ester bond, an amide bond, two carbons bonded by a double bond, two carbons bonded by a triple bond, and a thioether. It may be bonded via a bond.

Examples of the divalent non-aromatic hydrocarbon group containing two or more -CH _2- in the main skeleton include an alkylene group and an alkyleneoxy group, which have a substituent even if they have a substituent. It does not have to be. Here, examples of the substituent include a hydroxyl group, a halogen atom, an alkyl group, a cycloalkyl group, an alkoxy group, a cycloalkyloxy group, a silyl group, an acyl group, an acyloxy group, a carboxy group, a cyano group, a nitro group and a hydroxy group. Examples include a group selected from a mercapto group and an oxo group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The alkyl group used as the substituent may be either linear or branched. The number of carbon atoms of the alkyl group is preferably 1 to 20, more preferably 1 to 14, still more preferably 1 to 12, still more preferably 1 to 6, and particularly preferably 1 to 3. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and a nonyl group. , And a decyl group. As will be described later, the alkyl group used as a substituent may further have a substituent (secondary substituent). Examples of the alkyl group having such a secondary substituent include an alkyl group substituted with a halogen atom, and specifically, a trifluoromethyl group, a trichloromethyl group, a tetrafluoroethyl group, a tetrachloroethyl group and the like. Can be mentioned.

The number of carbon atoms of the cycloalkyl group used as the substituent is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and the like.

The alkoxy group used as the substituent may be either linear or branched. The alkoxy group has preferably 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group and a heptyloxy group. Examples thereof include an octyloxy group, a nonyloxy group, and a decyloxy group.

The number of carbon atoms of the cycloalkyloxy group used as the substituent is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 6. Examples of the cycloalkyloxy group include a cyclopropyloxy group, a cyclobutyloxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

The amino group used as the substituent may be either a linear or branched aliphatic or aromatic group. The number of carbon atoms of the amino group is preferably 1 to 20, preferably 1 to 12, and more preferably 1 to 6. Examples of the amino group include aminomethyl group, aminoethyl group, aminopropyl group, isopropylamino group, aminobutoxy group, sec-butylamino group, isobutylamino group, tert-butylamino group, aminopentyl group and aminohexyl. Examples thereof include a group, an aminoheptyl group, an aminooctyl group, an aminononyl group, an aminodecyl group, an aminophenyl group and the like.

The silyl group used as the substituent may be either linear or branched. The number of carbon atoms of the silyl group is preferably 1 to 20, preferably 1 to 12, and even more preferably 1 to 6. Examples of the silyl group include a methylsilyl group, an ethylsilyl group, a propylsilyl group, an isopropylsilyl group, a butoxysilyl group, a sec-butylsilyl group, an isobutylsilyl group, a tert-butylsilyl group, a pentylsilyl group, a hexylsilyl group and a heptylsilyl group. Examples include a group, an octylsilyl group, a nonylsilyl group, and a decylsilyl group.

The acyl group used as a substituent refers to a group represented by the formula: -C (= O) -R ¹ (in the formula, R ¹ is an alkyl group). The alkyl group represented by R ¹ may be linear or branched. The number of carbon atoms of the acyl group is preferably 2 to 20, more preferably 2 to 13, and even more preferably 2 to 7. Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, and a pivaloyl group.

The acyloxy group used as a substituent refers to a group represented by the formula: —OC (= O) —R ² (in the formula, R ² is an alkyl group). The alkyl group represented by ^R2 may be linear or branched. The number of carbon atoms of the acyloxy group is preferably 2 to 20, more preferably 2 to 13, and even more preferably 2 to 7. Examples of the acyloxy group include an acetoxy group, a propionyloxy group, a butyryloxy group, an isobutyryloxy group, and a pivaloyloxy group.

In addition to the two or more -CH _2- , the divalent non-aromatic hydrocarbon group containing two or more -CH _2- in the main skeleton further includes a cycloalkylene group, a cycloalkenylene group, a cycloalkynylene group, and an alkapolyenylene. It may contain a non-aromatic divalent group other than a methylene group, such as a group, an alkaziinylene group and an alkatolyinylene group.

Examples of the divalent non-aromatic hydrocarbon group containing two or more -CH _2- in the main skeleton include an alkylene group having 2 to 20 carbon atoms which may or may not have a substituent. Alternatively, an alkyleneoxy group having 2 to 20 carbon atoms, which may or may not have a substituent, is preferable. Here, the carbon number is a number excluding the carbon number of the substituent when it contains a substituent.

The alkyleneoxy group may have, for example, one or more of the structures represented by the following formulas (b1) to (b6).
(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)-
(B6)-(O-CH ₂ -CH (-CH ₃ )) _z -O-CH ₂ -CH (-OH)-
Here, p, r, u and w are integers of 1 to 20, preferably integers of 1 to 10, more preferably integers of 1 to 6, and even more preferably integers of 1 to 3. Further, q, s, t, v, y and z are integers of 1 to 20, preferably integers of 1 to 10, more preferably integers of 1 to 6, and even more preferably integers of 1 to 3.

(C) A divalent aromatic-containing hydrocarbon group containing a divalent aromatic group in the main skeleton In a divalent aromatic-containing hydrocarbon group containing a divalent aromatic group in the main skeleton, the aromatic group is For example, it may be a phenylene group, a naphthalene group, an anthracene group, or 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 of the aromatic groups. When two or more aromatic groups are contained, the aromatic group may be directly bonded, or may be bonded by an alkylene group, an ether bond, an ester bond, an amide bond, two carbons bonded by a double bond, or a triple bond. It may be bonded via the two carbons and the like. A particularly preferred divalent aromatic-containing hydrocarbon group is

（上記式中、＊は結合点を示す。）
及び

(In the above equation, * indicates a coupling point.)
as well as

（上記式中、＊は結合点を示す。）
を挙げることができる。

(In the above equation, * indicates a coupling point.)
Can be mentioned.

The epoxy compound having the structures shown in the above (a) to (c) preferably has a main skeleton in a chain shape rather than a cyclic shape. If the epoxy compound as a whole is chain-like, a divalent cyclic group such as a divalent aromatic group may be partially contained in the main skeleton. Further, the groups constituting the main skeleton may have the above-mentioned substituents. The polymer of the epoxy compound means a polymer obtained by polymerizing the epoxy compound to, for example, a polymer having a molecular weight of about 500 to 1500.

The flexible epoxy resin used in the present invention has the above-mentioned structure and characteristics, but more specifically, it is an epoxy compound represented by the following formula (2) or formula (3). It is preferable to contain those polymers.

In the formulas (2) and (3), m ¹ and m ² are independently integers of 1 to 20, preferably 1 to 10.

In formulas (2) and (3), X, X ¹ and X ² are divalent non-aromatic hydrocarbon groups containing two or more -CH _2- in the main skeleton. Here, the definition of a divalent non-aromatic hydrocarbon group containing two or more -CH _2- in the main skeleton is as described above. When m ¹ is an integer of 2 or more in the equation (2), the plurality of Xs may be the same or different from each other. X ¹ and X ² in the equation (3) may be the same or different from each other, and when m ² is an integer of 2 or more, a plurality of X ¹ may be the same or different from each other. The plurality of ^X2s may be the same or different from each other. X, X ¹ and X ² may be a group selected from the above-mentioned (b1) to (b6).

In formulas (2) and (3), Ar, Ar ¹ and Ar ² may be the same or different from each other, and may or may not have a substituent. It is a divalent aromatic-containing hydrocarbon group containing an aromatic group in its main skeleton. The definition of a divalent aromatic-containing hydrocarbon group containing a divalent aromatic group in the main skeleton is as described above. Ar ¹ and Ar ² in the equation (2) may be the same or different from each other, and when m ¹ is an integer of 2 or more, a plurality of Ar ¹ may be the same or different from each other. You may. When m ² in the equation (3) is an integer of 2 or more, a plurality of Ars may be the same or different from each other.

Further, the epoxy resin of the formula (3) may have a structure represented by the following formula (4).

In the formula (4), m ³ is an integer of 1 to 20, preferably an integer of 1 to 10.

The definitions of X ^3-6 and Ar ^3-4 in the formula (4) are the same as the definitions of X and Ar described above. X ³ , X ⁴ , X ⁵ , and X ⁶ in the formula (4) may be the same or different from each other. Further, when m ³ is an integer of 2 or more, a plurality of X ^5s may be the same or different from each other, and a plurality of X ^6s may be the same or different from each other. Ar ³ and Ar ⁴ may be the same as or different from each other. Further, when m ³ is an integer of 2 or more, a plurality of Ar ⁴ may be the same or different from each other. Further, X ^3-6 may be a group selected from the above-mentioned (b1) to (b6).

Examples of the structure of the flexible epoxy resin or a polymer thereof used in the present invention include the following structures (k is an integer of 1 to 20, preferably an integer of 1 to 5).

Further, for example, the following structure (h is an integer of 0 to 20, preferably an integer of 0 to 5, and i and j are independently integers of 1 to 20, preferably an integer of 1 to 5). Can be mentioned.

The epoxy equivalent of the flexible epoxy resin used in the present invention is, for example, 200 to 1000 g / eq, preferably 300 to 600 g / eq. When the epoxy equivalent is 200 or more, the viscosity is low, the viscosity is not low, and the viscosity is easy to handle, which is preferable. Further, when the epoxy equivalent of the epoxy resin is 1000 g / eq or less, the viscosity does not become high and it is suitable in terms of handling. Here, the epoxy equivalent is the mass of the epoxy resin containing one equivalent of the epoxy group, and can be measured according to, for example, JIS K 7236 (2009).

The flexible epoxy resin used in the present invention is preferably liquid at 25 ° C. By making it liquid at 25 ° C., the handleability of the one-component epoxy resin composition of the present invention is improved.

Specific examples of the flexible epoxy resin used in the present invention include, for example, EXA-4850-150, EXA-4816, and EXA-4822 manufactured by DIC; EP-4000S, EP-4000SS, EP-4003S manufactured by ADEKA. EP-4010S and EP-4011S; BEO-60E and BPO-20E manufactured by Shin Nihon Rika Co., Ltd .; YL7175-500, YL7175-1000, YL7410, and YX-7105 manufactured by Mitsubishi Chemical Corporation; and SR-FXB manufactured by Sakamoto Pharmaceutical Co., Ltd. Etc. are exemplified. These may be used alone or in combination of two or more.

[Epoxy resin other than (A) above]
An epoxy resin other than the above (A) (hereinafter, may be referred to as another epoxy resin) may be used in combination with the one-component epoxy resin composition of the present invention. Other epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, dicyclopentadiene type epoxy resin, and catechol. Polyglycidyl ether obtained by reacting polyhydric phenol such as resorcin or polyhydric alcohol such as glycerin or polyethylene glycol with epihalohydrin, glycidyl ether obtained by reacting hydroxycarboxylic acid such as p-oxybenzoic acid with epihalohydrin. A polyglycidyl ester obtained by reacting a polycarboxylic acid such as an ester, phthalic acid, or terephthalic acid with an epihalohydrin, obtained by reacting a polyglycidyl ester, 4,4-diaminodiphenylmethane, m-aminophenol, 4-aminophenol, etc. with an epihalohydrin. Examples thereof include polyglycidylamine type epoxy resins and phenol novolac type epoxy resins. Among these epoxy resins, bisphenol A type epoxy resin and bisphenol F type epoxy resin are preferable, and bisphenol A type epoxy resin is more preferable. These epoxy resins may be used alone or in combination of two or more. Further, it is preferable that the other epoxy resin is liquid at 25 ° C. By making it liquid at 25 ° C., the handleability of the one-component epoxy resin composition of the present invention is improved.

Specific examples of other epoxy resins that may be used in combination include bisphenol A type epoxy resins (Mitsubishi Chemical's "jER828EL", "jER827", "jER1001") and bisphenol F type epoxy resins (Mitsubishi Chemical's "jER807"). ”), Liquid bisphenol AF type epoxy resin (“ZX1059” manufactured by Nippon Steel Chemical Co., Ltd.), epoxy resin with hydrogenated structure (“YX8000” manufactured by Mitsubishi Chemical Co., Ltd.), dicyclopentadiene type polyfunctional epoxy resin (manufactured by DIC). "HP7200"), epoxy resin with butadiene structure ("PB-3600" manufactured by Daicel Chemical Industry Co., Ltd.), epoxy resin with biphenyl structure ("NC3000H", "NC3000L" manufactured by Nippon Kayaku Co., Ltd., "YX4000" manufactured by Mitsubishi Chemical Co., Ltd. ") And so on.

When another epoxy resin is used in combination, the amount thereof is, for example, 90 parts by weight or less, preferably 75 parts by weight or less, based on 100 parts by weight of the total epoxy resin in the one-component epoxy resin composition. By setting the amount of the other epoxy resin to 90 parts by weight or less, the flexibility of the obtained cured product can be further improved. Further, by using another epoxy resin in combination of 10 parts by weight or more, preferably 20 parts by weight or more, the adhesive strength can be further improved.

[(B) Thiol compound (at least including the compound represented by the above formula (1))]
The one-component epoxy resin composition of the present invention contains at least a thiol compound represented by the above formula (1). In the above formula (1), Z is a sulfur atom or an oxygen atom, preferably a sulfur atom. Further, in the above formula (1), the number of repeating units n ¹ and n ² are independently 2 or 3, respectively, and the flexibility can be further improved. Therefore, n ¹ = 3 and n ² are preferable. = 2.

In the present invention, the amount of (B) is such that the value obtained by (epoxy functional group equivalent) / (thiol functional group equivalent) is, for example, 0.7 to 1.4, preferably 0.8 to 1.2. The amount. Here, the thiol functional group equivalent means the number of all thiol groups in the one-component epoxy resin composition of the present invention, and the weight of each thiol compound in the resin composition is divided by each thiol equivalent. It is a value obtained by adding the added values. The thiol equivalent can be determined by dividing the molecular weight of the thiol compound by the number of thiol groups in one molecule of the thiol compound. On the other hand, the epoxy functional group equivalent means the number of all epoxy groups in the one-component epoxy resin composition of the present invention, and the weight of each epoxy resin in the resin composition is divided by each epoxy equivalent. It is a value obtained by adding the values.

Further, the one-component epoxy resin composition of the present invention may contain a thiol compound other than the thiol compound represented by the above formula (1) (hereinafter, may be referred to as another thiol compound). Specific examples of other thiol compounds that may be included include 1,3,4,6-tetrakis (2-mercaptoethyl) glycoluril and 1,3,4,6-tetrakis (3-mercaptopropyl) glycoluril. , 1,3,4,6-tetrakis (mercaptomethyl) glycoluril, 1,3,4,6-tetrakis (mercaptomethyl) -3a-methylglycoluryl, 1,3,4,6-tetrakis (2-mercapto) Ethyl) -3a-methylglycoluryl, 1,3,4,6-tetrakis (3-mercaptopropyl) -3a-methylglycoluryl, 1,3,4,6-tetrakis (mercaptomethyl) -3a, 6a-dimethyl Glycol uryl, 1,3,4,6-tetrakis (2-mercaptoethyl) -3a, 6a-dimethylglycol uryl, 1,3,4,6-tetrakis (3-mercaptopropyl) -3a, 6a-dimethyl glycol uryl , 1,3,4,6-tetrakis (mercaptomethyl) -3a, 6a-diphenylglycoluryl, 1,3,4,6-tetrakis (2-mercaptoethyl) -3a, 6a-diphenylglycoluryl, 1,3 , 4,6-Tetrakiss (3-mercaptopropyl) -3a, 6a-diphenylglycol A thiol compound having a glycol uryl skeleton such as uryl; 4,6-bis {3- [2- (1,3-dithietanyl)] methyl -5-Mercapto-2,4-dithiapentylthio} -1,3-dithian, 4,6-bis [4- (6-mercaptomethylthio) -1,3-dithianylthio] -6- [4- (6) -Mercaptomethylthio) -1,3-dithianilthio] -1,3-dithian, 4- [3,4,8,9-tetrakis (mercaptomethylthio) -11-mercapto-2,5,7,10-tetrathiaun Decyl] -5-mercaptomethylthio-1,3-dithiolan, 4,5-bis [3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiahexylthio] -1,3-dithiolan, 4- [3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiahexylthio] -5-mercaptomethylthio-1,3-dithiolan, 4- [3-bis (mercaptomethylthio) methyl- 5,6-bis (mercaptomethylthio) -8-mercapto-2,4,7-trithiaoctyl] -5-mercaptomethylthio-1,3-dithiolane, 2- {bis [3,4-bis (mercaptome) Chilthio) -6-mercapto-2,5-dithiohexylthio] methyl} -1,3-dithiolane, 2- [3,4-bis (mercaptomethylthio) -6-mercapto-2,5-dithiohexylthio ] Mercaptomethylthiomethyl-1,3-dithiolane, 2- [3,4,8,9-tetrakis (mercaptomethylthio) -11-mercapto-2,5,7,10-tetrathiaundesylthio] mercaptomethylthiomethyl- 1,3-Dithiolane, 2- [3-bis (mercaptomethylthio) methyl-5,6-bis (mercaptomethylthio) -8-mercapto-2,4,7-trithiaoctyl] mercaptomethylthiomethyl-1,3- Dithiotan, 4,5-bis {1- [2- (1,3-dithietanyl)]-3-mercapto-2-thiapropylthio} -1,3-dithiolane, 4- {1- [2- (1,3-) 3-Dithietanil)] -3-mercapto-2-thiapropylthio} -5- [1,2-bis (mercaptomethylthio) -4-mercapto-3-thiabutylthio] -1,3-dithiolane, 2-{bis [ 4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio] Methyl} -1,3-dithioetan, 4- [4- (5-Mercaptomethylthio-1,3-dithiolanyl) thio] -5- {1- [2- (1,3-dithiotanyl)]-3-mercapto-2-thiapropylthio} A thiol compound having a cyclic structure such as -1,3-dithiolane; 1,2,3-tris (mercaptomethylthio) propane , 1,2,3-Tris (2-mercaptoethylthio) propane, 1,2,3-tris (3-mercaptopropylthio) propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-Dimercaptomethyl-1,11-Dimercapto-3,6,9-Trithiandecan, 4,7-Dimercaptomethyl-1,11-Dimercapto-3,6,9-Trithiandecan, 4, 8-Dimercaptomethyl-1,11-Dimercapto-3,6,9-Trithiaundecane, Tetrax (mercaptomethylthiomethyl) methane, Tetrax (2-mercaptoethylthiomethyl) methane, Tetrax (3-mercaptopropylthiomethyl) Methan, 1,1,3,3-tetrakis (mercaptomethylthio) propane, 1,1,2,2-tetrakis (mercaptomethylthio) ethane, 4,6-bis (mercaptomethylthio) -1,3-dithiolane, 1, 1,5, 5-Tetrakiss (mercaptomethylthio) -3-thiapentane, 1,1,6,6-tetrakis (mercaptomethylthio) -3,4-dithiahexane, 2,2-bis (mercaptomethylthio) ethanethiol, 3-mercaptomethylthio-1 , 7-Dimercapto-2,6-dithiaheptane, 3,6-bis (mercaptomethylthio) -1,9-dimercapto-2,5,8-trithianonan, 3-mercaptomethylthio-1,6-dimercapto-2,5- Dithiahexane, 1,1,9,9-tetrakis (mercaptomethylthio) -5- (3,3-bis (mercaptomethylthio) -1-thiapropyl) 3,7-dithianonan, tris (2,2-bis (mercaptomethylthio)) Ethyl) methane, tris (4,4-bis (mercaptomethylthio) -2-thiabutyl) methane, tetrakis (2,2-bis (mercaptomethylthio) ethyl) methane, tetrakis (4,4-bis (mercaptomethylthio) -2 -Thiabutyl) methane, 3,5,9,11-tetrakis (mercaptomethylthio) -1,13-dimercapto-2,6,8,12-tetrathiatridecane, 3,5,9,11,15,17- Hexakis (mercaptomethylthio) -1,19-dimercapto-2,6,8,12,14,18-hexathianonadecane, 9- (2,2-bis (mercaptomethylthio) ethyl) -3,5,13, 15-Tetrakiss (mercaptomethylthio) -1,17-dimercapto-2,6,8,10,12,16-hexathiaheptadecan, 3,4,8,9-tetrakis (mercaptomethylthio) -1,11-dimercapto -2,5,7,10-tetrathiaundecane, 3,4,8,9,13,14-hexakis (mercaptomethylthio) -1,16-dimercapto-2,5,7,10,12,15-hexa Thiahexadecane, 8- [bis (mercaptomethylthio) methyl] -3,4,12,13-tetrakis (mercaptomethylthio) -1,15-dimercapto-2,5,7,9,11,14-hexathiapentadecane, 4,6-bis [3,5-bis (mercaptomethylthio) -7-mercapto-2,6-dithiaheptylthio] -1,3-ditian, 4- [3,5-bis (mercaptomethylthio) -7 -Mercapto-2,6-dithiaheptylthio] -6-mercaptomethylthio-1,3-dithian, 1,1-bis [4- (6-mercaptomethylthio)- 1,3-Dithianilthio] -1,3-bis (mercaptomethylthio) propane, 1- [4- (6-mercaptomethylthio) -1,3-dithianilthio] -3- [2,2-bis (mercaptomethylthio) ethyl ] -7,9-bis (mercaptomethylthio) -2,4,6,10-tetrathianedecane, 1,5-bis [4- (6-mercaptomethylthio) -1,3-dithianylthio] -3- [2 -(1,3-Dithietanyl)] methyl-2,4-dithiapentane, 3- [2- (1,3-dithietanyl)] methyl-7,9-bis (mercaptomethylthio) -1,11-dimercapto-2, 4,6,10-Tetrathioundecane, 9- [2- (1,3-dithietanyl)] methyl-3,5,13,15-tetrakis (mercaptomethylthio) -1,17-dimercapto-2,6,8 , 10,12,16-Hexachiaheptadecane, 3- [2- (1,3-dithietanyl)] methyl-7,9,13,15-tetrakis (mercaptomethylthio) -1,17-dimercapto-2,4 , 6,10,12,16-Hexachiaheptadecane, 3,7-bis [2- (1,3-dithietanyl)] methyl-1,9-dimercapto-2,4,6,8-tetrathianonan, etc. Fat group thiol compounds; bis (3-mercaptobutylyloxy) butane, tetraethylene glycol bis (3-mercaptopropionate), trimethylolpropanthris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene. Glycoldithioglycolate, trimethylolpropanthris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol poly (3-mercaptopropionate), tris-[(2-mercapto) Examples thereof include thiol compounds obtained by an esterification reaction between a polyol and a mercapto organic acid such as propionyloxy) -ethyl] -isocyanurate and tris-[(3-mercaptopropionyloxy) -ethyl] -isosianurate. Among these other thiol compounds, a thiol compound having a glycoluril skeleton is preferable, 1,3,4,6-tetrakis (2-mercaptoethyl) glycoluril and 1,3,4,6-tetrakis (3-mercaptopropyl). ) Glycol uryl is more preferred. Further, these may be used alone or in combination of two or more.

When other thiol compounds are used in combination, in order to further improve the flexibility of the obtained cured product, the amount of the other thiol compound is the total amount of the thiol compound represented by the above formula (1) and the other thiol compound. It is 40 parts by weight or less, preferably 20 parts by weight or less with respect to 100 parts by weight. Further, although sufficient adhesive strength can be obtained without using other thiol compounds in combination, it is preferable to use 1 part by weight or more, preferably 10 parts by weight or more of other thiol compounds in combination to further improve the adhesive strength.

[(C) Latent curing agent]
The latent curing agent contained in the one-component epoxy resin composition of the present invention is a compound that does not have activity with respect to the above-mentioned epoxy resin at room temperature (25 ° C.) but has a function of activating by heating and promoting curing. That is. In the present invention, the above-mentioned (B) thiol compound is not included in the latent curing agent even if it is a compound having the above-mentioned function.

The latent curing agent may be a solid or a liquid, but a solid latent curing agent is preferable because it can further improve the storage stability. Examples of the solid latent curing agent include an imidazole compound, an epoxy resin amine adduct compound, an epoxy resin imidazole adduct compound, a modified aliphatic polyamine compound, a dicyandiamide, and a microcapsule type latent curing agent, which are solid at room temperature. Among the latent curing agents of the above, epoxy resin amine adduct compounds, epoxy resin imidazole adduct compounds, modified aliphatic polyamine compounds, dicyandiamide and microcapsule type latent curing agents are preferable. These latent curing agents may be used alone or in combination of two or more.

Examples of the imidazole compound 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, 2,4-diamino-6- (2'-methyl) Imidazolyl- (1)')-Ethyl-S-triazine isocyanuric acid adduct, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Cyanoethyl-2-methylimidazole-trimethylate, 1-cyanoethyl-2-phenylimidazole-trimethylate, N- (2-methylimidazolyl-1-ethyl) -urea, N, N'-(2-methylimidazolyl- (1)- Ethyl) -aziboyldiamide and the like are exemplified. Examples of the epoxy resin amine adduct compound include Ajinomoto Fine-Techno Co., Ltd. Amicure MY-24, Amicure MY-R, and adduct compounds shown in JP-A-57-100127. Examples of the epoxy resin imidazole adduct compound include Ajinomoto Fine-Techno's Amicure PN-23, Amicure PN-R, and Air Product Japan's Sanmide LH-210. Examples of the modified aliphatic polyamine compound include FujiCure FXE-1000 and FujiCure FXR-1121 manufactured by T & K TOKA. As the microcapsule type latent curing agent, Asahi Kasei E-Materials NovaCure HX-3721, NovaCure HX-3722, NovaCure HX-3471, NovaCure HX-3742, NovaCure HX-3748, NovaCure HX-3613, NovaCure HX-3088 , NovaCure HX-3921HP, NovaCure HX-3941HP and the like are exemplified.

Examples of the liquid latent curing agent include Fujicure-7000, Fujicure-7001, and Fujicure-7002 manufactured by T & K TOKA.

The amount of (C) contained in the one-component epoxy resin composition of the present invention is, for example, 0.1 to 100 weight by weight with respect to 100 parts by weight of the total epoxy resin contained in the one-component epoxy resin composition of the present invention. Parts, preferably 1 to 60 parts by weight, more preferably 5 to 30 parts by weight.

[Stabilizer]
The one-component epoxy resin composition of the present invention may contain a stabilizer from the viewpoint of improving long-term storage stability. Examples of the stabilizer include borate compounds, titanate compounds, zirconate compounds, aluminate compounds, isocyanate compounds, carboxylic acids, acid anhydrides, mercapto organic acids and the like. Among these stabilizers, borate compounds are preferable from the viewpoint of versatility and safety, and among the borate compounds, triethyl borate, tri-n-propyl borate, triisopropyl borate, and tri-n-butyl borate are more preferable. Further, these stabilizers may be used alone or in combination of two or more.

[Other additives]
The one-component epoxy resin composition of the present invention further includes a reactive diluent, an additive (for example, an inorganic filler, a flame retardant, a sizing agent, a coupling agent, a colorant, a thixotropic agent, an antistatic agent, etc.) and the like. May include.

<Method for preparing one-component epoxy resin composition of the present invention>
For the preparation of the one-component epoxy resin composition of the present invention, a general stirring and mixing device and mixing conditions are applied in the same manner as in the usual method for preparing an epoxy resin composition. For example, flexible epoxy resins, thiol compounds (including at least the compound represented by the above formula (1)) and latent curing agents, and optionally other epoxy resins, reactive diluents, solvents and The one-component epoxy resin composition of the present invention can be prepared by sufficiently mixing the additives and the like until they become uniform. At that time, examples of the apparatus used include a mixing roll, a dissolver, a planetary mixer, a kneader, an extruder and the like. As the mixing conditions, the epoxy resin or the like may be dissolved and / or the viscosity may be reduced, and the mixture may be heated in order to improve the stirring and mixing efficiency. Further, it may be cooled as necessary in order to remove frictional heat generation, reaction heat generation and the like.

<Curing product obtained by curing the one-component epoxy resin composition of the present invention>
Subsequently, a method for producing a cured product obtained by curing the one-component epoxy resin composition of the present invention and the cured product will be described in detail.

The cured product obtained by curing the one-component epoxy resin composition of the present invention can be obtained, for example, by pouring the one-component epoxy resin composition of the present invention into a mold, casting it, and then curing it by heat. can. When curing by heat, the curing temperature varies depending on the type of curing agent and epoxy resin used, but is usually 50 to 150 ° C, preferably 60 to 120 ° C, and more preferably 70 to 100 ° C.

Since the one-component epoxy resin composition of the present invention provides a cured product having excellent low-temperature curability and excellent flexibility and adhesive strength, for example, an adhesive or a sealing agent for automobiles, home appliances and other electric parts. Can be suitably used as.

Hereinafter, the present invention will be described in more detail with reference to examples and the like, but the present invention is not limited thereto. In the examples and the like, each measured value was in accordance with the following method and measurement conditions.

[Flexibility confirmation test]
The one-component epoxy resin compositions obtained in each Example and Comparative Example were poured into each mold and heated at 80 ° C. for 120 minutes to prepare a cured product. The obtained cured product was processed to prepare a No. 3 dumbbell type test piece (thickness 3 mm). Tensile test [tensile speed: 5 mm / min, load FS: 5 kN, inter-chuck distance] for the above test piece using a Tensilon universal material tester (manufactured by Orientech Co., Ltd.) according to the measurement method of JIS K 7161. (Distance between marked lines): 60 mm] was performed, and the tensile elongation at break of the cured product was measured. The results are shown in Table 1.

[Adhesive strength test]
The one-component epoxy resin composition obtained in each Example and Comparative Example was applied to a steel plate (JIS3100 C1100P: 1.6 × 25 × 100 mm) as an adherend, and heated at 80 ° C. for 30 minutes. A test piece was prepared. The prepared test piece was allowed to cool in a room at 25 ° C., and the steel-steel tensile shear adhesive strength was measured according to the method for measuring the tensile shear adhesive strength in JIS K 6850.

<Examples 1 to 10, Comparative Example 1>
Weigh the materials into plastic containers so that the composition (parts by weight) shown in Table 1 is obtained, mix them sufficiently using a disper (ROBO MIX manufactured by TOKUSHU KIKA), defoam, and defoam the one-component epoxy resin composition. Got With respect to the obtained epoxy resin composition, the tensile elongation at break and the steel-steel tensile shear adhesive strength were measured according to the above measuring method. The results are shown in Table 1. The details of each material used are as follows.

EXA-4850-150: Vinyl ether-modified bisphenol type epoxy resin manufactured by DIC (epoxy equivalent: 435 g / eq)
DER331: Dow Chemical Co., Ltd., bisphenol A type epoxy resin (epoxy equivalent: 190 g / eq)
-Amicure PN-23: Ajinomoto Fine-Techno Co., Ltd., epoxy resin imidazole adduct compound-ACTOCURE (registered trademark) SS32: Kawaguchi Chemical Industry Co., Ltd., 1,3,5-tris [3- (2-mercaptoethylsulfanyl) propyl] Isocyanurate (Z is a sulfur atom in the above formula (1), n ¹ = 3, n ² = 2) (thiol equivalent: 177 g / eq)
ACTOCURE® ES23: Kawaguchi Chemical Industry Co., Ltd., 1,3,5-tris [2- (3-mercaptopropoxy) ethyl] isocyanurate (Z is an oxygen atom in the above formula (1), n ¹ = 2, n ² = 3) (thiol equivalent: 161 g / eq)
-C3TS-G: Shikoku Chemicals Corporation, 1,3,4,6-tetrakis (3-mercaptopropyl) glycoluril (thiol equivalent: 110 g / eq)
・ Aerosil 200: Fine powder silica manufactured by Nippon Aerosil

<Comparative Example 2>
Weigh 65 parts by weight of EXA-4850-150, 35 parts by weight of DER331, 15 parts by weight of Amicure PN-23, and 1 part by weight of Aerosil 200 in a plastic container, and mix them well using a disper (ROBO MIX manufactured by TOKUSHU KIKA). After that, defoaming was performed to obtain a one-component epoxy resin composition. The obtained epoxy resin composition was poured into a mold and heated at 80 ° C. for 120 minutes, but no cured product was obtained.

Claims (4)

A one-component epoxy resin composition containing the following (A) to (C).
(A) Flexible epoxy resin (B) Thiol compound (However, at least a thiol compound represented by the following formula (1) is included).

(In the formula, Z is a sulfur atom or an oxygen atom, and n ¹ and n ² are 2 or 3 independently, respectively.)
(C) Latent curing agent The one-component epoxy resin composition according to claim 1, further comprising an epoxy resin other than (A). The one-component epoxy resin composition according to claim 2, wherein the epoxy resin other than the above (A) is a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin. A cured product obtained by curing the one-component epoxy resin composition according to any one of claims 1 to 3.