Thiol-group-containing polyether polymer, epoxy-resin-containing composition, hardener for epoxy resins, and epoxy resin adhesive

Abstract

The present invention addresses the problem of providing a thiol-group-containing polyether polymer usable as a hardener with which epoxy adhesives can have a longer pot life than with conventional polymercaptan-based hardeners, while achieving a setting time comparable to those of the prior art.　This thiol-group-containing polyether polymer has a main chain including a polyether moiety represented by general formula (1) and a structural unit represented by general formula (2), and has a structural unit represented by general formula (3) at an end. (R1 is a residue formed by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol which has 10 or less carbon atoms, R2 is a C2-C6 alkylene group, n is an integer of 1-200, m is an integer of 2-8, l is an integer of 0-10, and X is an integer of 1-5.)

Description

Thiol group-containing polyether polymer, epoxy resin-containing composition, epoxy resin curing agent, and epoxy resin adhesive

[0001] The present invention relates to a thiol group-containing polyether polymer. The present invention also relates to an epoxy resin-containing composition that can bond with a setting time equivalent to that of conventional epoxy adhesives using polymercaptan curing agents while having a longer pot life than conventional epoxy adhesives using polymercaptan curing agents.

[0002] Epoxy resin-containing cured products have good adhesive properties, chemical resistance, low shrinkage, and excellent physical properties, and have been widely used as coatings, adhesives, and the like.

[0003] Among them, epoxy adhesives have good adhesive properties and chemical resistance. When fast curing and high adhesive strength are required, polythiol compounds are used as curing agents for epoxy adhesives. When polythiol compounds are used as curing agents for epoxy adhesives, they cure more quickly than other epoxy curing agents.

[0004] Numerous compounds containing terminal thiol groups that do not contain a polysulfide backbone 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 backbone in the main chain and three or more thiol groups per molecule are widely available commercially as curing agents for epoxy resins that combine economical efficiency and safety. Examples of compounds that have a polyether backbone 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" manufactured by Gabriel Performance Products. These polymercaptan-based curing agents are generally used by mixing an epoxy resin with a tertiary amine curing accelerator.

[0005] Epoxy adhesives that use a polymercaptan-based curing agent, a compound with a polyether backbone in the main chain and three or more thiol groups per molecule, cure in a pot life of about 2 to 10 minutes at room temperature. However, when the bonding area is large, a short pot life can cause the adhesive to harden and become unusable before it can be applied to the bonding surface. On the other hand, if the pot life of the adhesive is extended, the setting time will naturally be longer, raising concerns that this could significantly reduce work efficiency.

[0006] Therefore, there is a demand for an adhesive that can bond with a setting time equivalent to that of conventional epoxy adhesives that use polymercaptan-based curing agents while having a longer pot life.

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

[0008] An object of the present invention is to provide a thiol group-containing polyether polymer that can be used as a curing agent to provide bonding with a setting time equivalent to that of conventional epoxy adhesives using polymercaptan-based curing agents, while extending the pot life compared to conventional epoxy adhesives using polymercaptan-based curing agents.

[0009] A further object of the present invention is to provide an epoxy resin-containing composition as an adhesive that can bond with a setting time equivalent to that of conventional epoxy adhesives using polymercaptan-based curing agents while having a longer pot life than conventional epoxy adhesives.

[0010] The present invention and its preferred embodiments have the following configurations: [1] A polymer having a main chain containing a group represented by the following general formula (1):

[0011]

[0012] (In formula (1), R １ represents a residue obtained by removing a hydrogen atom from a polyamine or polyhydric alcohol having 10 or less carbon atoms, R ２ is an alkylene group having 2 to 6 carbon atoms, n is an integer of 1 to 200, and m is an integer of 2 to 8), and a polyether moiety represented by the following general formula (2):

[0013]

[0014] (in formula (2), X is an integer of 1 to 5, and l is an integer of 0 to 10), and has a structural unit represented by the following general formula (3) at its terminal:

[0015]

[0016] (in formula (3), l is an integer of 0 to 10). [2] The thiol group-containing polyether polymer according to [1], which contains 16% by mass to 20% by mass of thiol groups. [3] An epoxy resin-containing composition containing 100 to 600 parts by mass of an epoxy resin per 100 parts by mass of the thiol-containing polyether polymer according to [1] or [2]. [4] The epoxy resin-containing composition according to [3], which contains 1 to 60 parts by mass of an amine per 100 parts by mass of the epoxy resin. [5] The epoxy resin-containing composition according to [3] or [4], which has a pot life of 5.5 minutes to 25 minutes when the epoxy resin-containing composition containing 10 g of the epoxy resin is used and cured at 23°C and 50% RH. [6] The epoxy resin-containing composition according to any one of [3] to [5], wherein, when the epoxy resin-containing 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 50 or more and the tensile shear adhesive strength according to JIS K 6850 is 8 MPa or more 1 hour after the start of curing, and the Shore D hardness according to JIS K7215 is 60 or more and the tensile shear adhesive strength according to JIS K 6850 is 12 MPa or more 24 hours after the start of hardening. [7] An epoxy resin curing agent containing the thiol group-containing polyether polymer according to [1] or [2]. [8] An epoxy resin adhesive comprising the epoxy resin-containing composition according to any one of [3] to [6].

[0017] The thiol group-containing polyether polymer of the present invention can be used as a curing agent for epoxy resins, which has adhesive properties with a long pot life and a short setting time.

[0018] Furthermore, the epoxy resin-containing composition of the present invention can be used as an epoxy resin adhesive having adhesive properties with a long pot life and a short setting time.

[0019] Amine compounds are generally blended into epoxy adhesives that use polymercaptan curing agents. These amine compounds are blended as catalysts to accelerate the reaction between the polymercaptan compound and the epoxy compound, and the amount of amine compound significantly affects the adhesive's pot life. Naturally, a low amine content slows the reaction between the polymercaptan compound and the epoxy compound, extending the pot life, but the reaction is less likely to be completed, and ultimately requires a longer set time to achieve satisfactory adhesive strength and other adhesive functions. In other words, simply adjusting the amount of amine compound is not enough to achieve a curing agent that can bond with the same set time as conventional epoxy adhesives that use polymercaptan curing agents while extending the pot life.

[0020] The inventors focused on the crosslinking points of polymercaptan compounds to develop a polymercaptan curing agent that can bond with the same set time as conventional curing agents, even when the amount of amine compound is reduced and the workable life is extended. The crosslinking points of polymercaptan compounds form a higher-order structure after reaction with epoxy compounds, and as a result, it is expected that the hardness and adhesive strength required for an adhesive can be obtained relatively quickly. In other words, if the polymercaptan compound has many crosslinking points, it is believed that it will function as an adhesive with the same level of adhesiveness as conventional curing agents, and will be able to bond with the same set time as conventional curing agents, even when the workable life is extended and the reaction with epoxy compounds is limited.

[0021] The thiol group-containing polyether polymer of the present invention will now be described in detail.

[0022] The thiol group-containing polyether polymer has, in the main chain, a thiol group represented by the following general formula (1):

[0023]

[0024] (In formula (1), R １ represents a residue obtained by removing a hydrogen atom from a polyamine or polyhydric alcohol having 10 or less carbon atoms, R ２ is an alkylene group having 2 to 6 carbon atoms, n is an integer of 1 to 200, and m is an integer of 2 to 8), and a polyether moiety represented by the following general formula (2):

[0025]

[0026] (in formula (2), X is an integer of 1 to 5, and l is an integer of 0 to 10), and has a structural unit represented by the following general formula (3) at its terminal:

[0027]

[0028] (wherein l is an integer of 0 to 10)

[0029] R １ is a residue obtained by removing m hydrogen atoms from a polyvalent amine or polyhydric alcohol having 10 or less carbon atoms. m is an integer from 2 to 8, preferably an integer from 2 to 5. Examples of polyvalent amines and polyhydric alcohols having 10 or less carbon atoms include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, diglycerin, pentaerythritol, triethanolamine, ethylenediamine, and sucrose. These polyvalent amines and polyhydric alcohols may be used alone or in combination. Of the above polyhydric alcohols, glycerin, trimethylolpropane, and trimethylolethane are particularly preferred.

[0030] R ２ is an alkylene group having 2 to 6 carbon atoms, preferably an alkylene group having 2 to 4 carbon atoms. Examples of the alkylene group having 2 to 6 carbon atoms include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, pentylene, and hexylene.

[0031] n is an integer of 1 to 200, preferably an integer of 1 to 100. m is an integer of 2 to 8, preferably an integer of 2 to 5.

[0032] The thiol group-containing polyether polymer can be obtained by reacting a halogen-terminated polyether polymer with a metal hydrogen sulfide salt. The halogen-terminated polyether polymer can be obtained by (a) adding epihalohydrin to a polyol having a polyether moiety in the main chain and two or more hydroxyl groups at its terminals, and (b) adding epihalohydrin to the hydroxyl groups of the polyol. Furthermore, in order to increase the crosslinking points of the thiol group-containing polyether polymer of the present invention, it is important to add epihalohydrin in an amount exceeding the hydroxyl groups of the polyol.

[0033] The halogen-terminated polyether polymer has, in the main chain, a group represented by the following general formula (1):

[0034]

[0035] (In formula (1), R １ represents a residue obtained by removing a hydrogen atom from a polyamine or polyhydric alcohol having 10 or less carbon atoms, R ２ is an alkylene group having 2 to 6 carbon atoms, n is an integer of 1 to 200, and m is an integer of 2 to 8), and a polyether moiety represented by the following general formula (4):

[0036]

[0037] (in formula (4), X is a halogen atom, and l is an integer of 0 to 10) at the terminal.

[0038] The epihalohydrin is preferably epibromohydrin or epichlorohydrin, more preferably epichlorohydrin.

[0039] The amount of epihalohydrin used is 1.5 to 5.0 times by mole, preferably 1.6 to 3.0 times by mole, based on the hydroxyl groups of the polyol.

[0040] The polyol (hereinafter referred to as polyol) used in the synthesis of the thiol group-containing polyether polymer, which has a polyether moiety in the main chain and two or more hydroxyl groups at its terminals, is represented by the following general formula (5).

[0041]

[0042] (However, R １is 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 from 1 to 200, and m is an integer from 2 to 8.) Such polyols include those obtained by adding ethylene oxide, propylene oxide, tetrahydrofuran, or the like to polyhydric amines or polyhydric alcohols. Examples of polyhydric amines or polyhydric alcohols include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, and sucrose. These polyhydric amines and polyhydric alcohols may be used alone or in combination. Among the above polyols, polypropylene glycol obtained by adding propylene oxide to glycerin, trimethylolpropane, or trimethylolethane is particularly preferred.

[0043] The molecular weight of this polyol is usually 200 to 10,000, preferably 200 to 3,000.

[0044] The thiol group-containing polyether polymer of the present invention can be prepared by reacting the above-described halogen-terminated polyether polymer with a metal hydrogen sulfide salt. That is, by reacting with the metal hydrogen sulfide salt, the structure of the halogen-terminated polyether polymer represented by the general formula (4) is converted into the structure of the thiol group-containing polyether polymer represented by the general formula (2) and the general formula (3). Examples of metal hydrogen sulfide salts include potassium hydrogen sulfide, sodium hydrogen sulfide, lithium hydrogen sulfide, cesium hydrogen sulfide, and rubidium hydrogen sulfide. Of these, sodium hydrogen sulfide is preferred as the metal hydrogen sulfide salt. The metal hydrogen sulfide salt can also be used in the form of an aqueous solution, and the concentration of the metal hydrogen sulfide salt in the aqueous solution is 25% by mass or more, preferably 32% by mass or more, and more preferably 40% by mass or more to 70% by mass or less.

[0045] The metal hydrogen sulfide salt is preferably used in an amount of 1.0 to 5.0 times by mole, more preferably 1.1 to 1.5 times by mole, relative to the molar amount of halogen in the terminally halogenated polyether polymer. By using the metal hydrogen sulfide salt in this range, the halogen content in the thiol group-containing polyether polymer can be reduced. In electronic material applications, products, parts, and raw material components are required to be free of halogens and halogen compounds. The international standards IEC (International Electrotechnical Commission) 61249-2-21, IPC (Integrated Circuits and Packaging Association) 4101B, and the Japan Electronics Packaging and Circuits Association (JPCA) define halogen-free thresholds, requiring a chlorine (Cl) content of 0.09% by mass (900 ppm) or less.

[0046] When reacting a terminally halogenated polyether polymer with a metal hydrogen sulfide salt, a solvent may or may not be used. Examples of the solvent include alcohols such as methanol, ethanol, propanol, and butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; sulfoxides such as dimethyl sulfoxide; nitriles such as acetonitrile; amines such as pyridine; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; and water. Among these, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and water are particularly preferred.

[0047] When the above solvent is used, it is preferable to use the solvent in an amount of 0.2 to 5.0 times by mass, more preferably 1.0 to 3.0 times by mass, relative to the mass of the halogen-terminated polyether polymer.

[0048] When reacting a terminally halogenated polyether polymer with a metal hydrogen sulfide salt, a catalyst may or may not be used, but using a catalyst has the advantage of improving the reaction rate and quickly completing the reaction. Examples of catalysts include phase transfer catalysts such as tetrabutylammonium chloride (TBAC), tetrabutylammonium bromide (TBAB), tetrabutylammonium hydrogen sulfate (TBAHS), tributylmethylammonium chloride (MTBAC), benzyltrimethylammonium chloride (BTMAC), benzyltriethylammonium chloride (BTEAC), methyltrioctylammonium chloride (MTOAC), and tetrabutylphosphonium bromide (TBPB). Among these, TBAB and MTBAC are preferred.

[0049] When the above catalyst is used, the amount of the catalyst is preferably 0.005 to 0.2 times by mole, more preferably 0.01 to 0.1 times by mole, relative to the molar amount of halogen in the terminally halogenated polyether polymer.

[0050] When reacting a terminally halogenated polyether polymer with a metal hydrogen sulfide salt, the atmosphere in the reaction system may be, for example, air, an inert gas such as nitrogen or helium, or hydrogen sulfide. Among these, hydrogen sulfide is particularly preferred because it has the effect of reducing the viscosity of the resulting thiol group-containing polyether polymer.

[0051] Hydrogen sulfide may be introduced from outside the reaction system using a sealed vessel to confine the by-produced hydrogen sulfide, or may be introduced from outside the system using a hydrogen sulfide cylinder or the like. Furthermore, a hydrogen sulfide atmosphere may be created by the neutralization reaction of an acid with a metal hydrogen sulfide salt. Examples of acids that can be used in this case include organic carboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, citric acid, and lactic acid; organic sulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid; and inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. The amount of acid used is determined according to the internal pressure of the sealed vessel, which is preferably 0.01 to 2.0 MPa, and more preferably 0.05 to 1.0 MPa.

[0052] The reaction temperature when reacting the terminally halogenated polyether polymer with the metal hydrogen sulfide salt is preferably 40 to 130° C., more preferably 60 to 100° C. By setting the reaction temperature within this range, the halogen content of the resulting thiol group-containing polyether polymer can be reduced, and the viscosity can be made easy to handle.

[0053] The reaction time when reacting the terminally halogenated polyether polymer with the metal hydrogen sulfide salt is preferably 1 to 20 hours, more preferably 3 to 9 hours. By keeping the reaction time within this range, the halogen content of the resulting thiol group-containing polyether polymer can be reduced, ensuring efficient production.

[0054] The thiol group-containing polyether polymer of the present invention preferably has a halogen content of 900 ppm or less, more preferably 600 ppm or less, and even more preferably 300 ppm or less. By controlling the halogen content of the thiol group-containing polyether polymer within this range, it can be suitably used as an electronic material.

[0055] The crosslinking points of the thiol group-containing polyether polymer of the present invention can also be indicated by the thiol group content, and the thiol group content in the thiol group-containing polyether polymer is preferably 16% by mass or more, more preferably 16% by mass to 25% by mass, and even more preferably 16% by mass to 20% by mass.

[0056] The viscosity of the thiol group-containing polyether polymer of the present invention is preferably 9 to 30 Pa·s, more preferably 10 to 25 Pa·s.

[0057] The above-mentioned thiol-containing polyether polymer is preferably used as a curing agent for epoxy resins. The curing agent for epoxy resins of the present invention contains the thiol group-containing polyether polymer of the present invention.

[0058] The epoxy resin-containing composition of the present invention contains 100 to 600 parts by mass of an epoxy resin per 100 parts by mass of the above-described thiol-containing polyether polymer. This epoxy resin-containing composition can be used as an epoxy resin adhesive with a long pot life, a short setting time, and excellent adhesive properties. The thiol group-containing polyether polymer may be dissolved in a solvent, which can improve the coatability of the epoxy resin-containing composition. An alcohol-based solvent is preferably used as the solvent. From the viewpoint of being able to distill off the epoxy resin-containing composition with slight heating after application to a substrate or the like, alcohols with low boiling points are preferred, and in particular, methanol, ethanol, isopropanol, n-butanol, t-butanol, n-heptanol, n-hexanol, etc. are preferred due to their excellent compatibility with the thiol group-containing polyether polymer. Among these, methanol and ethanol, which have low molecular weights, are more preferred.

[0059] Examples of epoxy resins used in the epoxy resin-containing composition of the present invention 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; 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.), among which those that are liquid at room temperature are preferred.

[0060] In the epoxy resin-containing composition of the present invention, the epoxy resin is preferably contained in an amount of 100 to 600 parts by mass relative to 100 parts by mass of the thiol group-containing polyether polymer, more preferably 100 to 400 parts by mass, and even more preferably 100 to 200 parts by mass, relative to 100 parts by mass of the thiol group-containing polyether polymer.

[0061] The epoxy resin-containing composition of the present invention preferably contains an amine.

[0062] In the epoxy resin-containing composition of the present invention, the amines are preferably contained in an amount of 1 to 100 parts by mass, more preferably 1 to 60 parts by mass, per 100 parts by mass of the epoxy resin. Since the content of the amines affects the pot life, the amount used can be set depending on the design of the pot life.

[0063] The amines used in the epoxy resin-containing composition of the present invention may be those known as ordinary curing agents or catalysts for epoxy resins, and examples thereof include aliphatic diamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, trimethylenediamine, hexamethylenediamine, and tetramethylenediamine; aliphatic tertiary amines such as N,N-dimethylpropylamine and N,N,N',N'-tetramethylhexamethylenediamine; alicyclic tertiary amines such as N-methylpiperidine and N,N'-dimethylpiperazine; benzyldimethylamine, dimethylaminomethylphenol, and 2,4,6-tris(dimethylaminomethyl)phenol (manufactured by Evonik Industries / ANCAMINE). Further examples include polyamine epoxy resin adducts produced by reacting an epoxy resin with an excess of amine, polyamine-ethylene oxide adducts, polyamine-propylene oxide adducts, cyanoethylated polyamines, diamines having a silicon main chain, dehydration condensates obtained by reacting polyamines with phenols and aldehydes, imidazoles such as 2-ethyl-4-methylimidazole, and modified polyamines.

[0064] The epoxy resin-containing composition preferably has a pot life of 5.5 to 25 minutes when cured at 23°C and 50% RH. The pot life was measured with reference to the method for determining pot life of multi-component adhesives (Method 1) described in JIS K 6870. The pot life was measured by mixing 10 g of epoxy resin with a thiol-containing polyether polymer and an amine compound in a predetermined ratio under conditions of 23°C and 50% RH, and the pot life was defined as the point at which a toothpick inserted into the epoxy resin-containing composition no longer moves.

[0065] When the epoxy resin-containing composition is applied to a thickness of 6.0 mm or more and cured at 23°C and 50% RH, the Shore D hardness in accordance with JIS K7215 1 hour after the start of curing is preferably 50 or more, and the tensile shear adhesive strength in accordance with JIS K 6850 is preferably 8 MPa or more, and the Shore D hardness in accordance with JIS K7215 24 hours after the start of curing is preferably 60 or more, and the tensile shear adhesive strength in accordance with JIS K 6850 is preferably 12 MPa or more.

[0066] In this specification, the setting time refers to the time from the start of curing until the Shore D hardness according to JIS K7215 is 50 or more and the tensile shear adhesive strength according to JIS K6850 is 8 MPa or more when the epoxy resin-containing composition is applied to a thickness of 6.0 mm or more and cured at 23°C and 50% RH. The setting time of the epoxy resin-containing composition is preferably 1 hour or less. By keeping the setting time of the epoxy resin-containing composition to 1 hour or less, excellent work efficiency can be achieved.

[0067] The present invention will be specifically described below with reference to examples and comparative examples. 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.

[0068] Viscosity Measurement The viscosity of the sample was measured at 25°C using a viscometer U-EII manufactured by Toki Sangyo.

[0069] Measurement of thiol group content The sample was dissolved in a mixed solution of toluene and pyridine, and after adding an aqueous potassium iodide solution, titration was carried out using an iodine standard solution to measure the thiol group content.

[0070] Measurement of Halogen Amount The amount of halogen contained in the thiol group-containing polyether polymer was measured by measuring the chlorine content using a halogen measuring device (element analyzer, NSX-2100 manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

[0071] - Pot life The pot life of the epoxy resin-containing composition was determined by referring to the method for determining the pot life of a multi-component adhesive (Method 1) described in JIS K 6870. In the present invention, 10 g of epoxy resin was mixed with a thiol-containing polyether polymer and an amine compound in a predetermined ratio under conditions of 23°C and 50% RH, and a toothpick was placed in the epoxy resin-containing composition. The pot life was determined as the point at which the toothpick no longer moved when touched with a finger. The pot life was measured from the start of mixing, and the state of the toothpick was checked every 15 seconds to determine the pot life in minutes.

[0072] Hardness The hardness of the epoxy resin-containing composition was measured according to the method specified in JIS K 7215. Specifically, the epoxy resin-containing 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. Measurement samples with a diameter of 31 mm and a thickness of 8 mm were obtained 1 hour, 3 hours, 6 hours, and 24 hours after the start of pre-mixing of the epoxy resin-containing composition. The hardness of the flat surface of the sample was measured using a Type D durometer. The measurement was performed three times, and the average value was used as the hardness value.

[0073] Tensile Shear Adhesive Strength The tensile shear adhesive strength of the epoxy resin-containing composition was measured with reference to the method specified in JIS K 6850. The specific measurement method is described below. Adherend: The surface of a 100 mm × 25 mm × 3 mm mild steel plate (sandblasted) was degreased and surface-treated using acetone and then methyl ethyl ketone. Test specimen: Prepared in a room at a temperature of 23°C and a humidity of 50% RH to the dimensions specified in JIS K 6850. Specifically, the epoxy resin-containing composition was applied to the adherend, and the adherend was bonded to another adherend with an overlap length of 12.5 mm and an adhesive layer thickness of approximately 0.2 mm. The specimen was cured at a temperature of 23°C and a humidity of 50% RH. The tensile shear adhesive strength was measured 1 hour, 3 hours, and 24 hours after the start of pre-mixing of the epoxy resin-containing composition. Measurement method: The tensile shear adhesive strength was measured at a speed of 2.0 mm per minute in a room at a temperature of 23°C and a humidity of 50% RH using a tensile tester specified in JIS K 6850. Three test pieces were used for the measurement, and the average value was taken as the tensile shear adhesive strength value.

[0074] Set time When an epoxy resin-containing composition is applied to a thickness of 6.0 mm or more and cured at 23°C and 50% RH, the set time is the time from the start of curing until the Shore D hardness in accordance with JIS K7215 is 50 or more and the tensile shear adhesive strength in accordance with JIS K 6850 is 8 MPa or more.

[0075] Example 1: 250 g of trifunctional polypropylene glycol (OH value 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin and 2.4 g of stannous chloride pentahydrate were charged into a 1-liter reaction vessel, heated to 50°C, and 334 g of epichlorohydrin (1.6 times the molar amount of OH groups in the trifunctional polypropylene glycol) was added dropwise over 1 hour. After the dropwise addition, the mixture was stirred at 80°C for 2 hours to obtain a halogen-terminated polyether polymer. The halogen-terminated polyether polymer was then transferred to a sealed container, 15 g of citric acid was added, and the container was sealed. 925 g of an aqueous sodium hydrogen sulfide solution (48% concentration) was added dropwise to the sealed container, and the mixture was stirred at 95°C for 5 hours. The inorganic salts and water were then removed to obtain a colorless, transparent liquid polymer [thiol group-containing polyether polymer]. The resulting thiol group-containing polyether polymer had a thiol group content of 16.5% by mass, a chlorine content of 250 ppm, and a viscosity of 14.2 Pa·s (25° C.). The results are shown in Table 1.

[0076] Example 2: 100 g of trifunctional polypropylene glycol (OH value 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin and 1.0 g of stannous chloride pentahydrate were charged into a 1-liter reaction vessel, heated to 50°C, and 167 g of epichlorohydrin (2.0 times the molar amount of OH groups in the trifunctional polypropylene glycol) was added dropwise over 1 hour. After the dropwise addition, the mixture was stirred at 80°C for 2 hours to obtain a halogen-terminated polyether polymer. The halogen-terminated polyether polymer was then transferred to a sealed container, and 400 g of dimethylformamide and 13 g of citric acid were added, followed by sealing. 279 g of an aqueous sodium hydrogen sulfide solution (48% concentration) was added dropwise to the sealed container, followed by stirring at 95°C for 5 hours. The inorganic salts, water, and dimethylformamide were then removed to obtain a colorless, transparent liquid polymer [thiol group-containing polyether polymer]. The resulting thiol group-containing polyether polymer had a thiol group content of 18.8% by mass, a chlorine content of 260 ppm, and a viscosity of 10.1 Pa·s (25° C.). The results are shown in Table 1.

[0077] Example 3: 50 g of trifunctional polypropylene glycol (OH value 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin and 0.5 g of stannous chloride pentahydrate were charged into a 0.5-liter reaction vessel, heated to 50°C, and 125 g of epichlorohydrin (3.0 times the molar amount of OH groups in the trifunctional polypropylene glycol) was added dropwise over 1 hour. After the dropwise addition, the mixture was stirred at 80°C for 2 hours to obtain a halogen-terminated polyether polymer. The halogen-terminated polyether polymer was then transferred to a sealed container, and 263 g of dimethylformamide and 31 g of citric acid were added, followed by sealing. 219 g of an aqueous sodium hydrogen sulfide solution (48% concentration) was added dropwise to the sealed container, followed by stirring at 95°C for 5 hours. The inorganic salts, water, and dimethylformamide were then removed to obtain a colorless, transparent liquid polymer [thiol group-containing polyether polymer]. The resulting thiol group-containing polyether polymer had a thiol group content of 21.9% by mass, a chlorine content of 210 ppm, and a viscosity of 22.7 Pa·s (25° C.). The results are shown in Table 1.

[0078]

[0079] As shown in Table 1, the thiol group content of the thiol group-containing polyether polymers of Examples 1 to 3 is as high as 16% by mass or more, which means that there are many crosslinking points within the thiol group-containing polyether polymer. On the other hand, the conventional products described in Reference Example 1 ("Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd.) and Reference Example 2 ("Capcure 3-800" manufactured by Gabriel Performance Products) have a thiol group content of less than 16% by mass in the thiol compound, meaning that there are fewer crosslinking points within the thiol compound than in the thiol group-containing polyether polymers of Examples 1 to 3.

[0080] Example 4: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 1 as the thiol compound, and 0.3 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 5.9 minutes at 23°C. The Shore D hardness was 76 one hour after the start of curing, 77 three hours after the start of curing, and 78 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 16 MPa, after 3 hours it was 18 MPa, and after 24 hours it was 18 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0081] Example 5: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 1 as the thiol compound, and 0.1 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 9.6 minutes at 23°C. The Shore D hardness was 52 one hour after the start of curing, 54 three hours after the start of curing, and 64 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 11 MPa, after 3 hours it was 15 MPa, and after 24 hours it was 14 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0082] Example 6: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 2 (thiol compound), and 0.3 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 5.6 minutes at 23°C. The Shore D hardness was 76 one hour after the start of curing, 79 three hours after the start of curing, and 79 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 16 MPa, after 3 hours it was 14 MPa, and after 24 hours it was 15 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0083] Example 7: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 2 (thiol compound), and 0.1 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 10.7 minutes at 23°C. The Shore D hardness was 78 one hour after the start of curing, 79 three hours after the start of curing, and 79 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 14 MPa, after 3 hours it was 16 MPa, and after 24 hours it was 17 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0084] Example 8: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 3 (thiol compound), and 0.5 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 5.6 minutes at 23°C. The Shore D hardness was 78 one hour after the start of curing, 80 three hours after the start of curing, and 79 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 14 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 12 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 14 MPa, showing a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0085] Example 9: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) as the epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 3 as the thiol compound, and 0.3 g of ADEKA Corporation's EHC-30 as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 8.1 minutes at 23°C. The Shore D hardness was 74 one hour after the start of curing, 75 three hours after the start of curing, and 77 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 14 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 14 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 14 MPa, showing a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0086] Example 10: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) as the epoxy resin, 8.0 g of the thiol group-containing polyether polymer of Example 3 as the thiol compound, and 0.1 g of ADEKA Corporation's EHC-30 as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 20.4 minutes at 23°C. The Shore D hardness was 80 one hour after the start of curing, 82 three hours after the start of curing, and 82 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 9 MPa, after 3 hours it was 15 MPa, and after 24 hours it was 14 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 2.

[0087] Comparative Example 1: Under conditions of 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight 184-194) as the epoxy resin, 8.0 g of Toray Fine Chemicals Co., Ltd.'s "Polythiol QE-340M" as the thiol compound, and 1 g of ADEKA Corporation's EHC-30 as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a short pot life of 5.0 minutes in a 23°C environment. The Shore D hardness was 82 one hour after the start of curing, 83 three hours after the start of curing, and 83 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 16 MPa, after 3 hours it was 18 MPa, and after 24 hours it was 17 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 3.

[0088] Comparative Example 2: Under conditions of 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) as the epoxy resin, 8.0 g of Toray Fine Chemicals Co., Ltd.'s "Polythiol QE-340M" as the thiol compound, and 0.5 g of ADEKA Corporation's EHC-30 as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 8.2 minutes at 23°C. The Shore D hardness was 66 one hour after the start of curing, 70 three hours after the start of curing, and 76 24 hours after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 6 MPa, after 3 hours it was 9 MPa, and after 24 hours it was 13 MPa, meaning the tensile shear bond strength to mild steel plate after 1 hour was insufficient. The set time was between 1 and 3 hours. The results are shown in Table 3.

[0089] Comparative Example 3: Under conditions of 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight 184-194) as the epoxy resin, 8.0 g of Toray Fine Chemicals Co., Ltd.'s "Polythiol QE-340M" as the thiol compound, and 0.3 g of ADEKA Corporation's EHC-30 as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 12.3 minutes in a 23°C environment. Furthermore, the Shore D hardness was 28 one hour after the start of curing, 38 three hours after the start of curing, and 41 24 hours after the start of curing, indicating insufficient hardness as an adhesive. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. The tensile shear bond strength to mild steel plate after 1 hour at 23°C and 50% RH was 4 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 5 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 6 MPa, indicating insufficient tensile shear bond strength as an adhesive. The results are shown in Table 3.

[0090] Comparative Example 4: Under conditions of 23°C and 50% RH, 10.0 g of "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight 184-194) manufactured by Mitsubishi Chemical Corporation as the epoxy resin, 8.0 g of "Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd. as the thiol compound, and 0.1 g of EHC-30 (manufactured by ADEKA Corporation) as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The pot life of the resulting epoxy resin-containing composition in an environment of 23°C was 37.7 minutes. Furthermore, the Shore D hardness 1 hour after the start of curing was 1 or less, the Shore D hardness 3 hours after the start of curing was 14, and the Shore D hardness 24 hours after the start of curing was 16, indicating insufficient hardness as an adhesive. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. The tensile shear bond strength to mild steel plate after 1 hour at 23°C and 50% RH was 0.3 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 3 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 4 MPa, indicating insufficient tensile shear bond strength as an adhesive. The results are shown in Table 3.

[0091] Comparative Example 5: Under conditions of 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of Gabriel Performance Products' "Capcure 3-800" thiol compound, and 1 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a short pot life of 3.0 minutes at 23°C. The Shore D hardness was 78 one hour after the start of curing, 79 three hours after the start of curing, and 80 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. At 23°C and 50% RH, the tensile shear bond strength to mild steel plate after 1 hour was 16 MPa, after 3 hours it was 19 MPa, and after 24 hours it was 17 MPa, demonstrating a sufficiently high tensile shear bond strength as an adhesive even after 1 hour. The set time was less than 1 hour. The results are shown in Table 3.

[0092] Comparative Example 6: At 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" epoxy resin (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194), 8.0 g of Gabriel Performance Products' "Capcure 3-800" thiol compound, and 0.5 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a short pot life of 4.5 minutes at 23°C. The Shore D hardness was 78 one hour after the start of curing, 81 three hours after the start of curing, and 82 24 hours after the start of curing, demonstrating sufficient hardness as an adhesive even one hour after the start of curing. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. The tensile shear bond strength to mild steel plate after 1 hour at 23°C and 50% RH was 4 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 5 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 6 MPa, indicating insufficient tensile shear bond strength as an adhesive. The results are shown in Table 3.

[0093] Comparative Example 7: Under conditions of 23°C and 50% RH, 10.0 g of Mitsubishi Chemical Corporation's "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight: 184-194) epoxy resin, 8.0 g of Gabriel Performance Products' "Capcure 3-800" thiol compound, and 0.3 g of ADEKA Corporation's EHC-30 amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 5.5 minutes at 23°C. The Shore D hardness was 15 one hour after the start of curing, 25 three hours after the start of curing, and 32 24 hours after the start of curing, indicating insufficient hardness as an adhesive. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. The tensile shear bond strength to mild steel plate after 1 hour at 23°C and 50% RH was 2 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 3 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 4 MPa, indicating insufficient tensile shear bond strength as an adhesive. The results are shown in Table 3.

[0094] Comparative Example 8: Under conditions of 23°C and 50% RH, 10.0 g of "jER828" (bisphenol A-type epoxy resin, epoxy equivalent weight 184-194) manufactured by Mitsubishi Chemical Corporation as the epoxy resin, 8.0 g of "Capcure3-800" manufactured by Gabriel Performance Products as the thiol compound, and 0.1 g of EHC-30 (manufactured by ADEKA Corporation) as the amine compound were mixed with a spatula for 15 seconds to prepare an epoxy resin-containing composition. The resulting epoxy resin-containing composition had a pot life of 10.7 minutes in a 23°C environment. Furthermore, the Shore D hardness was 1 or less 1 hour after the start of curing, 7 after 3 hours after the start of curing, and 7 after 24 hours after the start of curing, indicating insufficient hardness as an adhesive. Furthermore, the tensile shear adhesive strength to mild steel plate was measured. The tensile shear bond strength to mild steel plate after 1 hour at 23°C and 50% RH was 2 MPa, the tensile shear bond strength to mild steel plate after 3 hours was 2 MPa, and the tensile shear bond strength to mild steel plate after 24 hours was 2 MPa, indicating insufficient tensile shear bond strength as an adhesive. The results are shown in Table 3.

[0095]

[0096] As shown in Table 2, by blending the thiol group-containing polyether polymers shown in Examples 1 to 3, as shown in the epoxy resin-containing compositions of Examples 4 to 10, it was found that sufficient bonding could be achieved with a set time of less than one hour, which is equivalent to the conventional setting time, despite the long pot life of 5.6 to 20.4 minutes.

[0097]

[0098] As shown in Table 3, in the epoxy resin-containing compositions of Comparative Examples 1 to 8, which used a conventionally widely available commercially available thiol group-containing polyether polymer, when the amount of the amine compound was reduced and the usable time was extended, it was not possible to achieve sufficient hardness or tensile shear adhesive strength.

Claims

1. In the main chain, the following general formula (1) (In formula (1), R １ R is a residue obtained by removing a hydrogen atom from a polyhydric amine or polyhydric alcohol having 10 or less carbon atoms; ２ is an alkylene group having 2 to 6 carbon atoms, n is an integer of 1 to 200, and m is an integer of 2 to 8), and a polyether moiety represented by the following general formula (2): (wherein X is an integer of 1 to 5, and l is an integer of 0 to 10), and the terminal of the structural unit represented by the following general formula (3) (wherein in formula (3), l is an integer of 0 to 10) 2. The thiol group-containing polyether polymer according to claim 1, which contains 16% by mass to 20% by mass of thiol groups.

3. An epoxy resin-containing composition comprising 100 to 600 parts by mass of an epoxy resin per 100 parts by mass of the thiol-containing polyether polymer according to claim 1 or 2.

4. The epoxy resin-containing composition according to claim 3, which contains 1 to 60 parts by mass of an amine relative to 100 parts by mass of the epoxy resin.

5. The epoxy resin-containing composition according to claim 3, wherein the pot life of the epoxy resin-containing composition containing 10 g of the epoxy resin when cured at 23°C and 50% RH is 5.5 to 25 minutes.

6. The epoxy resin-containing composition according to claim 3, wherein, when the epoxy resin-containing composition is applied to a thickness of 6.0 mm or more and cured at 23°C and 50% RH, 1 hour after the start of curing, the Shore D hardness according to JIS K7215 is 50 or more and the tensile shear adhesive strength according to JIS K 6850 is 8 MPa or more, and 24 hours after the start of hardening, the Shore D hardness according to JIS K7215 is 60 or more and the tensile shear adhesive strength according to JIS K 6850 is 12 MPa or more.

7. An epoxy resin curing agent containing the thiol group-containing polyether polymer according to claim 1 or 2.

8. An epoxy resin adhesive comprising the epoxy resin-containing composition according to claim 3.

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