Epoxy resin curable composition and adhesive containing same

Abstract

Provided is an epoxy resin curable composition that cures quickly and has a high hardness and excellent color tone after curing. This epoxy resin curable composition, which contains an epoxy resin having two or more epoxy groups per molecule, thiol compound A having two or more thiol groups per molecule, an amine compound having primary and / or secondary amino groups and thiol compound B represented by any of specific general formulae (1) to (3), is characterized in that: the thiol compound A and the thiol compound B are different from each other; and when the number of moles of the epoxy groups in the epoxy resin curable composition is regarded as Me, the number of moles of the thiol groups in the thiol compound A is regarded as MA and the number of moles of the thiol groups in the thiol compound B is regarded as MB, then the molar ratio MA / Me is 0.29-0.80 and the molar ratio MB / Me is 0.02-0.4.

Description

Epoxy resin curable composition and adhesive containing same

[0001] The present invention relates to a curable epoxy resin composition that cures quickly and gives a cured product with high hardness, strong adhesive strength, and excellent color tone after curing.

[0002] Epoxy resins have been widely used as adhesives because of their excellent adhesive properties, chemical resistance, and physical properties. For applications requiring fast curing and high adhesive strength, a method of adding a thiol compound as a curing agent and an amine as a curing accelerator is known.

[0003] Numerous compounds containing terminal thiol groups that do not contain a polysulfide skeleton in the main chain have been reported as compounds capable of rapidly reacting thiol groups with epoxy groups (see, for example, Patent Document 1). Among these, compounds that have a polyether skeleton in the main chain and three or more thiol groups per molecule are widely available commercially as curing agents for epoxy resins that are both economical and safe. Examples of compounds that have a polyether skeleton in the main chain and three or more thiol groups per molecule include "Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd., and "Capcure 3-800" and "GPM-800" manufactured by Gabriel Performance Products.

[0004] Examples of amines that are widely used as curing accelerators for thiol groups and epoxy groups include tertiary amines such as 2,4,6-tris(dimethylaminomethyl)phenol (ANCAMINE K-54, manufactured by Evonik Corporation), N,N-dimethylpropylamine, and bis(2-dimethylaminoethyl)ether.

[0005] However, conventionally known epoxy resin curable compositions turn yellow and become colored when cured, which poses a problem when used in applications requiring near colorlessness and excellent color tone, such as adhesives for glass and decorative items.

[0006] Conventionally known colorless epoxy resin curable compositions have slow curing properties, making them unsuitable for applications requiring rapid curing, and have not always provided sufficient hardness or adhesive strength. Thus, it has been difficult for an epoxy resin curable composition comprising an epoxy resin, a thiol compound, and an amine compound to simultaneously achieve rapid curing, hardness, adhesive strength, and color tone.

[0007] Japanese Patent Application Publication No. 8-269203

[0008] The present invention provides a curable epoxy resin composition that cures quickly, has high hardness after curing, and is excellent in color tone.

[0009] The epoxy resin curable composition of the present invention is an epoxy resin curable composition containing an epoxy resin having two or more epoxy groups in one molecule, a thiol compound A having two or more thiol groups in one molecule, an amine compound having a primary amine and / or a secondary amine, and a thiol compound B represented by any one of the following general formulas (1) to (3), wherein the thiol compound A and the thiol compound B are different from each other, and the number of moles of the epoxy groups contained in the epoxy resin curable composition is Me, and the number of moles of the thiol groups contained in the thiol compound A is M: A , the number of moles of thiol groups contained in the thiol compound B is M B , then the molar ratio M A / Me is 0.29 to 0.80, and the molar ratio M B / Me is 0.02 to 0.4. 2 ) n -C-(R 3 -O-CO-R 1 -SH) 4-n (1) (In general formula (1), R 1 are each independently an alkylene group having 1 to 10 carbon atoms, R 2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R 3 are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, and —SH is R 1 ) (R 2 ) n -C-(R3 -O-R 1 -SH) 4-n (3) (In general formula (3), R 1 are each independently an alkylene group having 1 to 10 carbon atoms, R 2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R 3 are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, and —SH is R 1 )

[0010] The epoxy resin curable composition of the present invention cures quickly, has high hardness and strong adhesive strength after curing, and has excellent color tone.

[0011] When the epoxy resin curable composition of the present invention is used as an adhesive, it exhibits strong adhesive strength to various adherends such as metals and glass. This epoxy resin curable composition can be used as an adhesive, a sealant, a potting material, a coating agent, a resin modifier, etc.

[0012] In particular, the epoxy resin curable composition of the present invention has excellent color tone and is therefore ideal for use as an adhesive for glass, an adhesive for decorative items, an adhesive for watch parts, an adhesive for electrical and electronic applications, a potting material for electrical and electronic applications, and an adhesive for everyday carpentry.

[0013] The curable epoxy resin composition of the present invention contains an epoxy resin having two or more epoxy groups in one molecule, a thiol compound A having two or more thiol groups in one molecule, an amine compound having a primary amino group and / or a secondary amino group, and a thiol compound B represented by a specific structural formula and different from thiol compound A.

[0014] Examples of epoxy resins having two or more epoxy groups per molecule include epoxy resins obtained by adding epichlorohydrin to polyhydric phenols such as bisphenol A, bisphenol F, resorcinol, hydroquinone, pyrocatechol, 4,4-dihydroxybiphenyl, and 1,5-hydroxynaphthalene, epoxy resins obtained by adding epichlorohydrin to polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin, and epoxy resins obtained by adding epichlorohydrin to aromatic dicarboxylic acids such as hydroxybenzoic acid and phthalic acid, and polysulfide polymers having epoxy groups at their terminals (trade names "FLEP-50" and "FLEP-60," both manufactured by Toray Fine Chemicals Co., Ltd.). Epoxy resins having two or more epoxy groups per molecule are preferably liquid at room temperature from the viewpoints of workability and preventing poor mixing. Examples of epoxy resins having two or more epoxy groups in one molecule include jER-828 (trade name, manufactured by Mitsubishi Chemical Corporation), DER-331 (trade name, manufactured by Dow Chemical Corporation), jER-825 (trade name, manufactured by Mitsubishi Chemical Corporation), jER-827 (trade name, manufactured by Mitsubishi Chemical Corporation), jER-806 (trade name, manufactured by Mitsubishi Chemical Corporation), and jER-807 (trade name, manufactured by Mitsubishi Chemical Corporation).

[0015] The epoxy resin having two or more epoxy groups in one molecule preferably has an epoxy equivalent of 50 to 1000 g / eq, and more preferably has an epoxy equivalent of 100 to 300 g / eq.

[0016] The epoxy resin curable composition contains at least two types of thiol compounds, namely, thiol compound A and thiol compound B, and thereby the composition can be cured quickly, have high hardness and strong adhesive strength after curing, and have an excellent color tone.

[0017] The thiol compound B is a compound different from the thiokol compound A and is a thiol compound represented by any one of the following general formulas (1) to (3): (R 2 ) n -C-(R 3 -O-CO-R1 -SH) 4-n (1) (In general formula (1), R 1 are each independently an alkylene group having 1 to 10 carbon atoms, R 2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R 3 are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, and —SH is R 1 ) (R 2 ) n -C-(R 3 -O-R 1 -SH) 4-n (3) (In general formula (3), R 1 are each independently an alkylene group having 1 to 10 carbon atoms, R 2 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R 3 are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, and —SH is R 1 )

[0018] In general formula (1), a plurality of R 1 are each independently an alkylene group having 1 to 10 carbon atoms, preferably an alkylene group having 2 to 7 carbon atoms, and more preferably an alkylene group having 2 to 4 carbon atoms. 1 may be the same or different. 1 Examples of the alkyl group include a methylene group, an ethylene group, a propylene group, a 1-methylethylene group, a butylene group, an ethylethylene group, and a dimethylethylene group.

[0019] In general formula (1), a plurality of R 3 are each independently an alkylene group having 1 to 3 carbon atoms, preferably an alkylene group having 1 to 2 carbon atoms. 3 may be the same or different. 3 Examples of the alkyl group include a methylene group, an ethylene group, a propylene group, and a methylethylene group.

[0020] In general formula (1), a plurality of R2 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group having 1 to 2 carbon atoms. 3 may be the same or different. 3 Examples of the hydroxyalkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, etc. Examples of the hydroxyalkyl group include a methylol group, a hydroxyethyl group, and a hydroxypropyl group.

[0021] In the general formula (1), n ​​represents an integer of 0 to 2, and —SH represents an alkylene group R 1 It bonds to any carbon atom that makes up the

[0022] Examples of the thioether compound B represented by general formula (1) include 1,4-bis(3-mercaptopropionyloxy)butane, 1,4-bis(3-mercaptobutyryloxy)butane, trimethylolpropane tris(3-mercaptopropionate), trimethylolpropane tris(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptoisobutyrate), trimethylolpropane tris(2-mercaptoisobutyrate), trimethylolpropane tristhioglycolate, pentaerythritol tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptoisobutyrate), pentaerythritol tetrakis(2-mercaptoisobutyrate), and pentaerythritol tetrakisthioglycolate.

[0023] In general formula (3), a plurality of R 1 are each independently an alkylene group having 1 to 10 carbon atoms, preferably an alkylene group having 2 to 7 carbon atoms, and more preferably an alkylene group having 2 to 4 carbon atoms. 1 may be the same or different. 1Examples of the alkyl group include a methylene group, an ethylene group, a propylene group, a 1-methylethylene group, a butylene group, an ethylethylene group, and a dimethylethylene group.

[0024] In general formula (3), a plurality of R 3 are each independently an alkylene group having 1 to 3 carbon atoms, preferably an alkylene group having 1 to 2 carbon atoms. 3 may be the same or different. 3 Examples of the alkyl group include a methylene group, an ethylene group, a propylene group, and a methylethylene group.

[0025] In general formula (3), a plurality of R 2 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group having 1 to 2 carbon atoms. 3 may be the same or different. 3 Examples of the hydroxyalkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, etc. Examples of the hydroxyalkyl group include a methylol group, a hydroxyethyl group, and a hydroxypropyl group.

[0026] In the general formula (3), n represents an integer of 0 to 2, and —SH represents an alkylene group R 1 It bonds to any carbon atom that makes up the

[0027] Examples of the thioether compound B represented by general formula (3) include trimethylolpropane monopropanethiol, trimethylolpropane bis(propanethiol), trimethylolpropane tris(propanethiol), pentaerythritol monopropanethiol, pentaerythritol bis(propanethiol), pentaerythritol tris(propanethiol), and pentaerythritol tetrakis(propanethiol).

[0028] The thiol compound A is a compound different from the above-mentioned thiokol compound B, and is a thiol compound containing two or more thiol groups per molecule. The thiol compound A preferably has a polyether moiety in the main chain and a thiol group on the carbon adjacent to the carbon having a hydroxyl group. Furthermore, the thiol compound A preferably does not have a carbonyl group. The absence of a carbonyl group in the thiol compound A is preferred because it inhibits hydrolysis of the cured product and improves water resistance.

[0029] The structure having a polyether moiety in the main chain is preferably represented by the following general formula (4), and the terminal thiol group is preferably represented by the following formula (5). (However, R 1 is a residue obtained by removing m hydrogen atoms from a polyamine or polyhydric alcohol having 10 or less carbon atoms, and R 2 is an alkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 200, and m is an integer of 2 to 8.

[0030] In the general formula (4), R 1 is a residue obtained by removing m hydrogen atoms from a polyhydric amine or polyhydric alcohol having 10 or less carbon atoms. Examples of polyhydric amines or polyhydric alcohols having 10 or less carbon atoms include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, diglycerin, pentaerythritol, triethanolamine, ethylenediamine, and sucrose. These polyhydric amines and polyhydric alcohols may be used alone or in combination. Among the above polyols, glycerin, trimethylolpropane, and trimethylolethane are particularly preferred.

[0031] In the general formula (4), R 2 is an alkylene group having 2 to 4 carbon atoms. Examples of the alkylene group having 2 to 4 carbon atoms include ethylene, n-propylene, isopropylene, n-butylene, and isobutylene.

[0032] In the general formula (4), n is an integer of 1 to 200, preferably an integer of 1 to 100. Furthermore, m is an integer of 2 to 8, preferably an integer of 2 to 5.

[0033] Examples of the thiol compound A having the structure represented by the general formula (4) and formula (5) and having no carbonyl group include "Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd., and "Capcure3-800" and "GPM-800" manufactured by Gabriel Performance Products.

[0034] The thiol compound A containing two or more thiol groups in one molecule preferably has at least one thiol group represented by the formula (5), and more preferably has two or more thiol groups. All of the thiol groups in the thiol compound A may be contained as the structure represented by the formula (5).

[0035] The thiol compound A containing two or more thiol groups in one molecule preferably has a thiol group content of 1 to 50% by mass, more preferably 5 to 20% by mass.

[0036] The phrase "thiol compound A does not have a carbonyl group" means that thiol compound A does not have a carbonyl group, a carboxy group, a thiocarboxy group, an amide group, an ester bond, a thioester bond, or the like.

[0037] The epoxy resin and thiol compound described above are present in the epoxy resin curable composition, and the ratio of the moles of thiol groups derived from thiol compound A to the moles of epoxy groups derived from the epoxy resin, M A Molar ratio M A / Me is 0.29 to 0.8, and the number of moles M of thiol groups derived from thiol compound B relative to the number of moles Me of epoxy groups derived from the epoxy resin present in the epoxy resin curable composition is B Molar ratio M B / Me is 0.02 to 0.4.

[0038] Molar ratio M A If the molar ratio M / Me is less than 0.29, the curing rate will be slow. AWhen the molar ratio M / Me exceeds 0.8, the Shore D hardness of the cured product of the epoxy resin curable composition cannot be increased. B If the molar ratio M / Me is less than 0.02, the Shore D hardness of the cured product cannot be increased. B If the molar ratio M / Me exceeds 0.4, the Shore D hardness of the cured product of the epoxy resin curable composition will be lowered. A The amount of each compound can be determined so that the molar ratio M / Me is preferably 0.29 to 0.7, more preferably 0.29 to 0.65, and even more preferably 0.29 to 0.57. B The amount of each compound can be determined so that / Me is preferably 0.02 to 0.3, more preferably 0.03 to 0.2, and even more preferably 0.04 to 0.14.

[0039] The epoxy resin curable composition is a composition having a molar number M of thiol groups derived from thiol compound A present in the composition. A The number of moles M of thiol groups derived from thiol compound B relative to B Molar ratio M B / M A is preferably 0.02 to 0.5, more preferably 0.04 to 0.4, and even more preferably 0.13 to 0.34. B / M A If the molar ratio M is 0.02 or more, the Shore D hardness of the cured product becomes high, which is preferable. B / M A When the value is 0.5 or less, the curing rate becomes high, which is preferable.

[0040] The amount of thiol compound A blended is determined based on the above-mentioned molar ratio M A / Me, and preferably satisfies the molar ratio M B / M AThe amount of thiol compound A can be appropriately designed so as to satisfy the above relationship and depending on the physical properties of the epoxy resin curable composition. For example, it is preferable to blend 50 to 150 parts by mass of thiol compound A per 100 parts by mass of epoxy resin having two or more epoxy groups per molecule. When the amount of thiol compound A is 50 to 150 parts by mass per 100 parts by mass of epoxy resin, the resulting epoxy resin curable composition cures quickly, the hardness of the cured product is high, and it has sufficient adhesive strength. The amount of thiol compound A blended per 100 parts by mass of epoxy resin is more preferably 60 to 120 parts by mass, and even more preferably 70 to 100 parts by mass.

[0041] The thiol compound B is a thiol compound having the molar ratio M B / Me, and preferably satisfies the molar ratio M B / M A The composition can be designed appropriately so as to satisfy the above relationship and depending on the physical properties of the epoxy resin curable composition. For example, it is preferable to blend 1 to 40 parts by mass of thiol compound B per 100 parts by mass of an epoxy resin having two or more epoxy groups per molecule. When the amount of thiol compound B is 1 to 40 parts by mass per 100 parts by mass of epoxy resin, a cured product with high Shore D hardness and excellent curing rate can be obtained. The amount of thiol compound B blended per 100 parts by mass of epoxy resin is more preferably 1 to 20 parts by mass, and even more preferably 2 to 12 parts by mass.

[0042] The epoxy resin curable composition contains an amine compound having a primary amino group and / or a secondary amino group. The amine compound may have only primary amino groups derived from a primary amine, only secondary amino groups derived from a secondary amine, or may have primary amino groups derived from a primary amine and secondary amino groups derived from a secondary amine.

[0043] The amine compound is preferably an aliphatic amine. Examples of aliphatic amines include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,5-diaminopentane, hexamethylenediamine, tetramethylenediamine, trimethylhexamethylenediamine, 2-methyl-1,5-diaminopentane, polyetherdiamine, 1,3-diaminopropane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, and bis(hexamethylene)triamine. It is preferable that the amine compound is not an amine in which the amino group of the aliphatic amine is composed solely of secondary amino groups. In other words, it is preferable that the aliphatic amine has at least one primary amino group.

[0044] The amine compound is more preferably an amine having two or more primary amino groups and / or two or more secondary amino groups in one molecule, but no tertiary amino group. Examples of the amine compound include ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,5-diaminopentane, hexamethylenediamine, tetramethylenediamine, trimethylhexamethylenediamine, 2-methyl-1,5-diaminopentane, polyetherdiamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, bis(hexamethylene)triamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, and bis(hexamethylene)triamine. More preferred examples of the amine having two or more amino groups in one molecule and no tertiary amino group in the molecule include ethylenediamine, diethylenetriamine, triethylenetetramine, 1,3-diaminopropane, and tetraethylenepentamine.

[0045] The amine compound more preferably has three or more primary amino groups and / or secondary amino groups per molecule. Preferred amines having three or more amino groups per molecule include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, and bis(hexamethylene)triamine, with triethylenetetramine being more preferred.

[0046] The amine compound is particularly preferably a modified product made from an amine having three or more primary amino groups and / or secondary amino groups per molecule. Modified products made from an amine having three or more amino groups per molecule are particularly preferably modified products of diethylenetriamine, triethylenetetramine, or tetraethylenepentamine, and more preferably modified products obtained by reacting the amino groups of triethylenetetramine with a mono- or polyepoxy compound. An example of a modified product made from an amine having three or more amino groups per molecule is "BB-AMINE 3138" manufactured by BB Resins SRL.

[0047] The modified product made from an amine having three or more amino groups in one molecule preferably has an amine value of 500 to 2500 KOHmg / g, more preferably 800 to 1700 KOHmg / g.

[0048] The amount of the amine compound can be appropriately designed depending on the physical properties of the cured product. For example, it is preferable to blend 1 to 30 parts by mass of the amine compound per 100 parts by mass of an epoxy resin having two or more epoxy groups per molecule. When the amount of the amine compound is 1 to 30 parts by mass per 100 parts by mass of the epoxy resin, a cured product can be obtained that cures quickly, has sufficient adhesive strength, and is excellent in color toning. The amount of the amine compound per 100 parts by mass of the epoxy resin is more preferably 2 to 30 parts by mass, and even more preferably 5 to 30 parts by mass.

[0049] The epoxy resin curable composition of the present invention cures at room temperature. The epoxy resin curable composition has an excellent color tone after curing, being colorless and / or nearly white. In the present invention, the color tone is excellent when the L of a cured product having a thickness of 8 mm is measured. * a * b * Chromaticity a in the color system * is -10 to +10, and b * is -15 to +15. * If the value is outside the range of −10 to +10, the color tone becomes dark. * a * b * Chromaticity a in the color system * is −8 to +8, and b * The curable epoxy resin composition preferably has an L of 8 mm after curing under conditions of 23°C and 50% RH for 24 hours. * a * b * Chromaticity a in the color system * is −8 to +5, and b * The color of the cured product is -10 to +15. * is more preferably −7 to +3, and even more preferably −5 to +1. * is more preferably −7 to +13, even more preferably −5 to +12, and particularly preferably −1 to +11.

[0050] The epoxy resin curable composition has a cured product with a thickness of 8 mm and a color tone of L. * a * b * In the color space of the color system, lightness L * is preferably 50 or more, more preferably 55 or more, and even more preferably 60 or more.

[0051] Said L * a * b * The color space of a color specification system is a method of displaying colors, which was established by the International Commission on Illumination (CIE) in 1976. It physically measures the amount of color light stimulation that causes color sensation, and expresses lightness (L *value), the degree of magenta and green (a * value), yellow and blue levels (b * The L * A value of 0 represents black, a value of 100 represents white, and * If the value is negative, it represents a greenish color, and if it is positive, it represents a reddish color. * Negative values ​​represent bluer colors, positive values ​​represent yellower colors.

[0052] Said L * a * b * The color space can be measured using a colorimeter (for example, a colorimeter manufactured by Minolta under the trade name "CR-300"), which is a measuring device specified in Japanese Industrial Standards JIS Z 8781-4:2013.

[0053] The curing time of the epoxy resin curable composition is preferably 1 to 20 minutes. The curing time of the epoxy resin curable composition is more preferably 1 to 15 minutes, and even more preferably 1 to 10 minutes, when 10 g of the epoxy resin curable composition is used and cured at 23°C and 50% RH. A curing time of 1 to 15 minutes is suitable for applications requiring fast curing and is therefore preferred.

[0054] The curing time was measured with reference to the method for determining the pot life of a multi-component adhesive (Method 1) described in JIS K 6870. A thiol compound and an amine compound were mixed in a predetermined ratio with 10 g of epoxy resin under conditions of 23°C and 50% RH, and the curing time was defined as the point at which a toothpick inserted into the epoxy resin curable composition no longer moved.

[0055] When the epoxy resin curable composition is applied to a thickness of 6.0 mm or more and cured at 23°C and 50% RH, the Shore D hardness according to JIS K7215 after 3 hours of curing is preferably 70 or more, and the Shore D hardness according to JIS K7215 after 24 hours of curing is preferably 75 or more. A Shore D hardness of 70 or more after 3 hours of curing is preferred, as it results in a cured product with strong adhesive strength. The Shore D hardness after 3 hours of curing is more preferably 71 to 85, and even more preferably 73 to 84. Furthermore, a Shore D hardness of 75 or more after 24 hours of curing is preferred, as it results in a cured product with strong adhesive strength. The Shore D hardness after 24 hours of curing is more preferably 76 to 85, and even more preferably 78 to 84.

[0056] The epoxy resin curable composition may further contain a filler, a plasticizer, a flexibility-imparting agent, a coupling agent, an antioxidant, a thixotropy-imparting agent, a dispersant, etc., within the scope of not impairing the object of the present invention.

[0057] The epoxy resin curable composition of the present invention can be used as an adhesive that adheres well to metals, glass, stone, concrete, etc. and has excellent color tone. Adhesives containing this epoxy resin curable composition are suitable as adhesives for iron plates, glass, decorative items, watch parts, and everyday carpentry, for example, and are particularly suitable as adhesives for glass, decorative items, watch parts, and everyday carpentry.

[0058] Examples and comparative examples are shown below. In the following examples, unless otherwise specified, common reagents purchased from reagent manufacturers were used as raw materials. The following equipment and methods were used for analysis.

[0059] Curing Time: The curing time of the epoxy resin curable composition was defined as the point at which a toothpick inserted into the epoxy resin curable composition no longer moves, based on the method for determining the pot life of multi-component adhesives (Method 1) described in JIS K 6870. Specifically, a toothpick was inserted into the epoxy resin curable composition obtained by mixing the raw materials according to each example at 23°C and 50% RH, and the curing time was measured at the point at which the toothpick no longer moves. The curing time was measured from the start of mixing and determined in minutes by checking the condition of the toothpick every 30 seconds. In Examples 1 to 4 and Comparative Examples 1 to 12, thiol compound A, thiol compound B, and an amine compound were mixed with 10 g of epoxy resin in the proportions shown in Tables 1 and 2.

[0060] Hardness (Shore D Hardness) The hardness of the epoxy resin curable composition was measured according to the method specified in JIS K 7215. Specifically, the epoxy resin curable composition was poured into multiple containers with an inner diameter of 31 mm and a depth of 8 mm in a room at a temperature of 23°C and a humidity of 50% RH. 3 hours and 24 hours after the start of mixing the epoxy resin curable composition, measurement samples with a diameter of 31 mm x 8 mm were obtained. The flat surfaces of the samples were measured using a Type D durometer. The measurement was performed three times for each measurement sample, and the average value was used as the hardness value.

[0061] Lightness and chromaticity The lightness and chromaticity of the cured epoxy resin were measured. Specifically, using a color difference meter (Minolta "CR-300") specified in JIS Z 8781-4, the curable epoxy resin composition according to each example was placed in a container with an inner diameter of 31 mm and a depth of 8 mm and cured at 23°C and 50% RH. After 24 hours, the cured epoxy resin was removed from the container, and the lightness L of the 8 mm-thick cured epoxy resin was measured. * , chromaticity a * , chromaticity b * was measured at room temperature. * and b * The measurement results are shown in Tables 1 and 2.

[0062] Example 1 Under the conditions of 23°C and 50% RH, 10 g (100 parts by mass) of "jER828" (bisphenol A type epoxy resin, epoxy equivalent of 184 to 194 g / eq) manufactured by Mitsubishi Chemical Corporation as an epoxy resin having two or more epoxy groups in one molecule, 7.9 g (79 parts by mass) of "Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd. as a thiol compound A having two or more thiol groups in one molecule, and "TMMP" (trimethylolpropane tris(3-mercaptopropionate) manufactured by SC Organic Chemical Industry Co., Ltd. as a thiol compound B, a bisphenol A type epoxy resin having an epoxy equivalent of 184 to 194 g / eq) manufactured by Mitsubishi Chemical Corporation as an epoxy resin having two or more epoxy groups in one molecule were used. 1 is an ethylene group, R 2 is an ethyl group, R 3 A curable epoxy resin composition was obtained by mixing 1.0 g (10 parts by mass) of thiol compound A (wherein "TMMP" is a methylene group) and 1.1 g (11 parts by mass) of BB-AMINE 3138 manufactured by BB RESINS SRL as an amine compound having a primary amino group and / or a secondary amino group with a spatula for 15 seconds. The number of moles of epoxy groups contained in the curable epoxy resin composition is Me, and the number of moles of thiol groups derived from thiol compound A is M. A and the number of moles M of thiol groups derived from thiol compound B B are shown in Table 1. The molar ratio M A / Me, M A / Me, and M B / M A was calculated and recorded.

[0063] The curing time of the obtained epoxy resin curable composition at 23°C was measured, and it cured in 6 minutes. The Shore D hardness was 73 3 hours after the start of curing, and 78 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is -3, b * The result was 7. The results are shown in Table 1.

[0064] Example 2 Thiol compound B was obtained from TMMP using "PEMP" (pentaerythritol tetrakis(3-mercaptopropionate), manufactured by SC Organic Chemical Co., Ltd., a compound represented by the general formula (1) where n is 0 and R1 is an ethylene group, R 3 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amount of 1.0 g (10 parts by mass) of 1,2-dimethylaminomethylpropional (DMPO) was changed to 1.0 g (10 parts by mass).

[0065] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 6 minutes. The Shore D hardness was 77 3 hours after the start of curing, and 80 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -3, b * The result was 7. The results are shown in Table 1.

[0066] Example 3 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 4.0 g (40 parts by mass) and the amount of thiol compound B was changed to 0.3 g (3 parts by mass).

[0067] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 6 minutes. The Shore D hardness was 76 3 hours after the start of curing, and 80 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -5, b * The result was 7. The results are shown in Table 1.

[0068] Example 4 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 4.0 g (40 parts by mass), 0.3 g (3 parts by mass), and 3.0 g (30 parts by mass), respectively.

[0069] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 3 minutes. The Shore D hardness was 82 3 hours after the start of curing, and 81 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -5, b * The result was 11. The results are shown in Table 1.

[0070] Comparative Example 1 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 8.9 g (89 parts by mass) and thiol compound B was not blended.

[0071] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 6 minutes. The Shore D hardness was 72 3 hours after the start of curing, and 73 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -5, b * The result was 7. The results are shown in Table 1.

[0072] Comparative Example 2 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 0.1 g (1 part by mass) and the amount of thiol compound B was changed to 8.8 g (88 parts by mass).

[0073] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 11 minutes. The Shore D hardness was 37 3 hours after the start of curing, and 47 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is 0, b * The result was 10. The results are shown in Table 1.

[0074] Comparative Example 3 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 11.9 g (119 parts by mass) and the amount of thiol compound B was changed to 4.0 g (40 parts by mass).

[0075] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 7 minutes. The Shore D hardness was 18 3 hours after the start of curing, and 18 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is 0, b * The result was 10. The results are shown in Table 1.

[0076] Comparative Example 4 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 11.9 g (119 parts by mass) and the amount of thiol compound B was changed to 0.3 g (3 parts by mass).

[0077] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 7 minutes. The Shore D hardness was 42 3 hours after the start of curing, and 40 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -2, b * The result was 8. The results are shown in Table 1.

[0078] Comparative Example 5 A curable epoxy resin composition was obtained in the same manner as in Example 1, except that the amount of thiol compound A was changed to 4.0 g (40 parts by mass) and the amount of thiol compound B was changed to 4.0 g (40 parts by mass).

[0079] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 6 minutes. The Shore D hardness was 76 3 hours after the start of curing, and 74 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is -1, b * The result was 8. These results are shown in Table 2.

[0080] Comparative Example 6 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 11.9 g (119 parts by mass), 4.0 g (40 parts by mass), and 3.0 g (30 parts by mass), respectively.

[0081] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 4 minutes. The Shore D hardness was 7 3 hours after the start of curing, and 5 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is 2, b * The result was 10. The results are shown in Table 2.

[0082] Comparative Example 7 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 11.9 g (119 parts by mass), 4.0 g (40 parts by mass), and 0.5 g (5 parts by mass), respectively.

[0083] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 24 minutes. The Shore D hardness was 19 3 hours after the start of curing, and 19 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is -2, b * The result was 8. These results are shown in Table 2.

[0084] Comparative Example 8 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 11.9 g (119 parts by mass), 0.3 g (3 parts by mass), and 3.0 g (30 parts by mass), respectively.

[0085] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 3 minutes. The Shore D hardness was 21 3 hours after the start of curing, and 18 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is 0, b * The result was 10. The results are shown in Table 2.

[0086] Comparative Example 9 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 11.9 g (119 parts by mass), 0.3 g (3 parts by mass), and 0.5 g (5 parts by mass).

[0087] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 14 minutes. The Shore D hardness was 34 3 hours after the start of curing, and 51 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured, and the chromaticity a * is -4, b * The result was 6. These results are shown in Table 2.

[0088] Comparative Example 10 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 4.0 g (40 parts by mass), 4.0 g (40 parts by mass), and 3.0 g (30 parts by mass), respectively.

[0089] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 3 minutes. The Shore D hardness was 52 3 hours after the start of curing, and 50 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -5, b * The result was 12. These results are shown in Table 2.

[0090] Comparative Example 11 An epoxy resin curable composition was obtained in the same manner as in Example 1, except that the amounts of thiol compound A, thiol compound B, and amine compound were changed to 4.0 g (40 parts by mass), 4.0 g (40 parts by mass), and 0.5 g (5 parts by mass), respectively.

[0091] The curing time at 23°C was measured in the same manner as in Example 1, and the composition cured in 30 minutes. The Shore D hardness was 51 3 hours after the start of curing, and 77 24 hours after the start of curing. Furthermore, the chromaticity of the cured product of the epoxy resin curable composition was measured. * is -2, b * The result was 8. These results are shown in Table 2.

[0092]

[0093]

Claims

1. An epoxy resin curable composition containing an epoxy resin having two or more epoxy groups in one molecule, a thiol compound A having two or more thiol groups in one molecule, an amine compound having a primary amino group and / or a secondary amino group, and a thiol compound B represented by any one of the following general formulas (1) to (3), wherein the amine compound does not have a tertiary amino group, and the thiol compound A and the thiol compound B are different from each other, the number of moles of the epoxy groups contained in the epoxy resin curable composition is Me, the number of moles of the thiol groups contained in the thiol compound A is M, Ａ The number of moles of the thiol group contained in the thiol compound B is M Ｂ , where the molar ratio M Ａ / Me is 0.29 to 0.80, and the molar ratio M Ｂ A curable epoxy resin composition in which M B / M A is 0.02 to 0.5 and M B / M A is 0.02 to 0.

5. (R ２ ) ｎ -C-(R ３ -O-CO-R １ -SH) ４－ｎ (1) (In the general formula (1), R １ are each independently an alkylene group having 1 to 10 carbon atoms; R ２ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R ３ are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, -SH is R １ ) 【Chemistry 1】 (R) ２ ) ｎ -C-(R ３ -O-R １ -SH) ４－ｎ (3) (In the general formula (3), R １ are each independently an alkylene group having 1 to 10 carbon atoms; R ２ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 3 carbon atoms, R ３ are each independently an alkylene group having 1 to 3 carbon atoms, n is an integer of 0 to 2, -SH is R １ )

2. The epoxy resin curable composition according to claim 1 , wherein the thiol compound A has no carbonyl group.

3. L of the cured product ＊ a ＊ b ＊ The chromaticity in the color system is a ＊ is -10 to +10, b ＊ The epoxy resin curable composition according to claim 1 or 2, wherein is −15 to +15.

4. 3. The epoxy resin curable composition according to claim 1, wherein the curing time when 10 g of the epoxy resin curable composition is cured at 23° C. and 50% RH is 1 to 15 minutes.

5. 3. The epoxy resin curable composition according to claim 1 or 2, wherein when the epoxy resin curable composition is applied to a thickness of 6.0 mm or more and cured at 23° C. and 50% RH, the Shore D hardness according to JIS K7215 is 70 or more 3 hours after the start of curing, and the Shore D hardness according to JIS K7215 is 75 or more 24 hours after the start of curing.

6. The epoxy resin curable composition according to claim 1 or 2, which is used as an adhesive.

7. An adhesive comprising the epoxy resin curable composition according to claim 1 or 2.

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