Polymer compositions, epoxy resin compositions, epoxy resin curing agents, and fast-curing adhesives

Abstract

An objective of the present invention is to obtain: a polymer composition that can be used as a curing agent of an epoxy resin having a high curing rate even in a low temperature environment as well as low viscosity and favorable stability; and an epoxy resin composition.　The present invention is a polymer composition comprising a polyether polymer having a thiol group, wherein the polyether polymer containing a thiol group has a polyether portion expressed by the following chemical formula (1) in a main chain and a structural unit expressed by the following formula (2) on an end, and the amount of thiol groups in the polyether polymer containing a thiol group is 8 weight% Formula (1): R1[-(R2O)n]m- Where R1 represents a residual group obtained by removing a hydrogen atom from a polyhydric alcohol or a polyamine having 10 or fewer carbon atoms; R2 represents an alkylene group having 2 to 6 carbon atoms; n is a number between 1 and 200; and m is a number between 2 and 8. Formula (2): -CH2CH(OH)CH2-SH

Description

[Technical Field]

[0001] The present invention relates to epoxy resin compositions, curing agents for epoxy resins, and fast-curing adhesives. [Background technology]

[0002] Cured products containing epoxy resins have good adhesion, chemical resistance, low shrinkage rate, and excellent physical properties, and have been widely used as paints and adhesives.

[0003] Among these, epoxy adhesives possess good adhesion and chemical resistance. When rapid 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, curing is faster compared to other epoxy curing agents.

[0004] Many compounds containing terminal thiol groups that do not have a polysulfide skeleton in their main chain have been reported as compounds that can rapidly react thiol groups with epoxy groups (see, for example, Patent Document 1). Among these, compounds having a polyether skeleton in their main chain and three or more thiol groups in one molecule are widely available as epoxy resin curing agents that combine economy and safety. Examples of compounds having a polyether skeleton in their main chain and three or more thiol groups in one molecule include "Polythiol QE-340M" manufactured by Toray Fine Chemicals Co., Ltd. and "Capcure3-800" manufactured by Gabriel Performance Products. Generally, these polymercaptan-based curing agents are used by mixing them with epoxy resin and a tertiary amine, which is a curing accelerator.

[0005] Epoxy adhesives using a polymercaptan-based curing agent that has a polyether skeleton in its main chain and contains three or more thiol groups per molecule cure in about 2 to 10 minutes at room temperature. While epoxy adhesives using a polymercaptan-based curing agent that has a polyether skeleton in its main chain and contains three or more thiol groups per molecule cure quickly at room temperature, they have the problem of curing slowly at relatively low temperatures below 15°C, and curing is slow in winter or cold environments.

[0006] Therefore, there was a need for an epoxy adhesive that cured quickly even in low-temperature environments. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 8-269203 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a polymer composition that can be used as a curing agent for epoxy resins, which has a fast curing rate even in low-temperature environments, low viscosity, and good stability and adhesion.

[0009] Another object of the present invention is to provide an epoxy resin-containing composition as a curing agent for epoxy resins that has a fast curing rate even in low-temperature environments, low viscosity, and good stability and adhesion. [Means for solving the problem]

[0010] The present invention relates to a polymer composition comprising a polyether polymer having thiol groups, wherein the polyether polymer having thiol groups has a polyether portion represented by the following chemical formula (1) in its main chain and a structural unit represented by the following formula (2) at its terminal, the thiol group content of the polyether polymer having thiol groups is 8% by mass or more, and the polymer composition further comprises a cationic surfactant. R 1 [-(R 2 O) n ] m - …Equation (1) However, R 1 R is a residue obtained by removing a hydrogen atom from a polyhydric amine or polyhydric alcohol with 10 or fewer carbon atoms, 2 is an alkylene group with 2 to 6 carbon atoms, where n is 1 to 200 and m is 2 to 8. -CH2CH(OH)CH2-SH...Formula (2).

[0011] The present invention also relates to an epoxy resin composition containing the polymer composition of the present invention and an epoxy resin, wherein the content of the epoxy resin is 100 to 600 parts by mass per 100 parts by mass of the polyether polymer having thiol groups.

[0012] Furthermore, the present invention relates to a curing agent for epoxy resins that contains the polymer composition of the present invention.

[0013] Furthermore, the present invention relates to a fast-curing adhesive containing the polymer composition of the present invention, an epoxy resin, and amines. [Effects of the Invention]

[0014] The polymer composition of the present invention can be used as a curing agent for epoxy resins that has a fast curing rate even in low-temperature environments, low viscosity, and good stability and adhesion.

[0015] Furthermore, the epoxy resin composition of the present invention has a fast curing rate even in low-temperature environments, and possesses low viscosity, good stability, and adhesive properties. [Modes for carrying out the invention]

[0016] [Polyether polymer having a thiol group] The polymer composition of the present invention contains a polyether polymer having a thiol group.

[0017] The polyether polymer having a thiol group has a polyether moiety represented by the following chemical formula (1) in the main chain. R 1 [-(R 2 O) n m - … Formula (1).

[0018] R 1 is a residue obtained by removing m hydrogen atoms from a polyvalent amine or polyhydric alcohol having 10 or less carbon atoms.

[0019] Examples of the polyvalent amine or polyhydric alcohol having 10 or less carbon atoms include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, diglycerin, pentaerythritol, triethanolamine, ethylenediamine, sucrose, and the like. These polyvalent amines and polyhydric alcohols may be used alone or in combination. Among the above polyols, glycerin, trimethylolpropane, and trimethylolethane are particularly preferred.

[0020] <000用いることができる。R 2 is an alkylene group having 2 to 6 carbon atoms. Examples of the alkylene group having 2 to 6 carbon atoms include ethylene, n-propylene, isopropylene, n-butylene, isobutylene, and the like.

[0021] n is 1 to 200, preferably 1 to 100. Also, m is 2 to 8, preferably 2 to 5.

[0022] The polyether polymer having a thiol group has a structural unit represented by the following formula (2) at the terminal. -CH2CH(OH)CH2-SH … Formula (2) ​The structural unit represented by formula (2) can preferably be obtained by reacting a halogen-terminated polyether polymer obtained by adding an epihalohydrin with an alkali hydrosulfide and / or a polysulfide in a polar solvent.

[0023] The halogen-terminated polyether polymer is obtained by adding an epihalohydrin (b) to a polyol (a) having a polyether moiety in its main chain and two or more hydroxyl groups at its terminus.

[0024] To synthesize the polyether polymer having the thiol group, the polyol (a) has a chemical structure represented by the following general formula (3). R 1 [-(R 2 O) n ] m …(3) However, R 1 R is a residue obtained by removing m hydrogen atoms from a polyhydric amine or polyhydric alcohol with 10 or fewer carbon atoms, 2 is an alkylene group with 2 to 4 carbon atoms, where n is 1 to 200 and m is 2 to 8.

[0025] Examples of the polyol (a) include those obtained by adding ethylene oxide, propylene oxide, tetrahydrofuran, etc., to a polyhydric amine or polyhydric alcohol. Examples of polyhydric amines or polyhydric alcohols include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, sucrose, etc. 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.

[0026] The molecular weight of the polyol (a) is preferably 200 to 10,000, and more preferably 200 to 3,000.

[0027] The polyether polymer having thiol groups has a thiol group content of 8% by mass or more, preferably 8 to 16% by mass, and more preferably 9 to 16% by mass.

[0028] From the viewpoint of ease of handling, the viscosity of the polyether polymer having the thiol group is preferably 9 to 17 Pa·s, and more preferably 12 to 14 Pa·s.

[0029] [Cationic surfactants] The polymer composition of the present invention further contains a cationic surfactant. The inclusion of the cationic surfactant promotes the reaction, enabling rapid curing even in low-temperature environments.

[0030] The cationic surfactant (B) is preferably a quaternary ammonium salt or a quaternary phosphonium salt.

[0031] Examples of quaternary ammonium salts include tetrabutylammonium fluoride, benzyltributylammonium chloride, benzyltriethylammonium chloride, benzyltrimethylammonium chloride, tetra-n-butylammonium chloride, tetraethylammonium chloride, methyltributylammonium chloride, benzyltri-n-butylammonium bromide, benzyltriethylammonium bromide, benzyltrimethylammonium bromide, n-octyltrimethylammonium bromide, hexyltrimethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium bromide, and tetradecyltrimethylammonium bromide. Preference candidates include tetrabutylammonium bromide, tetra-n-propylammonium bromide, tetraoctylammonium bromide, tetrabutylammonium iodide, tetraethylammonium iodide, tetra-n-propylammonium iodide, trimethylphenylammonium iodide, tetrabutylammonium hydrogen sulfate, benzyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydrogen sulfate, and tetrabutylammonium tetrafluoroborate.

[0032] Examples of quaternary phosphonium salts include tetrabutylphosphonium fluoride, benzyltributylphosphonium chloride, benzyltriethylphosphonium chloride, benzyltrimethylphosphonium chloride, tetra-n-butylphosphonium chloride, tetraethylphosphonium chloride, methyltributylphosphonium chloride, benzyltri-n-butylphosphonium bromide, benzyltriethylphosphonium bromide, benzyltrimethylphosphonium bromide, n-octyltrimethylphosphonium bromide, hexyltrimethylphosphonium bromide, tetrabutylphosphonium bromide, tetraethylphosphonium bromide, and tetradecyltrimethylphosphonium bromide. Tetra-n-propylphosphonium bromide, tetraoctylphosphonium bromide, tetrabutylphosphonium iodide, tetraethylphosphonium iodide, tetra-n-propylphosphonium iodide, trimethylphenylphosphonium iodide, tetrabutylphosphonium bisulfate, benzyltrimethylphosphonium hydroxide, phenyltrimethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrapropylphosphonium hydroxide, tetrabutylphosphonium hydrogen sulfate, tetrabutylphosphonium tetrafluoroborate, etc. are preferred.

[0033] Furthermore, tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium hydrogen sulfate, tetrabutylphosphonium bromide, tetraoctylammonium bromide, benzyltriethylammonium chloride, and methyltributylammonium chloride are more preferred as the cationic surfactant.

[0034] Furthermore, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, tetrabutylphosphonium bromide, tetraoctylammonium bromide, benzyltriethylammonium chloride, and methyltributylammonium chloride are even more preferred as cationic surfactants.

[0035] The aforementioned cationic surfactants can be used individually, or multiple surfactants can be used in combination.

[0036] The content of the cationic surfactant in the polymer composition of the present invention is preferably 0.01 to 5.0% by mass. By setting the content to 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more, the curing speed can be effectively increased. Furthermore, by setting the content to 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.0% by mass or less, it is advantageous in terms of cost.

[0037] In the present invention, the cationic surfactant can be added at any time. It may be added directly to the polyether polymer having thiol groups, or it may be added in a post-treatment step after the reaction that synthesizes the polyether polymer having thiol groups. It may also be added at the stage of the reaction that synthesizes the polyether polymer having thiol groups. Regardless of the timing of addition, the same effect can be obtained as long as the composition contains the cationic surfactant component.

[0038] The polymer composition of the present invention may contain the thiol-group-containing polyether polymer and cationic surfactant dissolved in a solvent. In this embodiment, the applicability of the polymer composition is improved.

[0039] Preferably, an alcohol-based solvent is used as the solvent. From the viewpoint that the polymer composition can be removed by distillation with slight heating after being applied 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 because they have excellent compatibility with the thiol-group-containing polyether polymer and the cationic surfactant. Among these, methanol and ethanol, which have low molecular weights, are more preferred.

[0040] [Hardener for epoxy resins] The polymer composition of the present invention is suitably used as a curing agent for epoxy resins. That is, the curing agent for epoxy resins of the present invention contains the polymer composition of the present invention.

[0041] [Epoxy resin composition] The epoxy resin composition of the present invention contains the polymer composition and epoxy resin of the present invention.

[0042] Examples of the epoxy resins 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 oxybenzoic acid and phthalic acid; and polysulfide polymers having epoxy groups at their ends (product names "FLEP-50" and "FLEP-60," both manufactured by Toray Fine Chemicals Co., Ltd.).

[0043] The epoxy resin is preferably one that is liquid at room temperature.

[0044] The epoxy resin content in the epoxy resin composition of the present invention is preferably 80 to 600 parts by mass per 100 parts by mass of the polyether polymer having thiol groups. More preferably, this content is 100 to 400 parts by mass, and even more preferably 120 to 200 parts by mass.

[0045] The epoxy resin composition of the present invention preferably contains amines.

[0046] The content of the amines in the epoxy resin composition of the present invention is preferably 1 to 100 parts by mass per 100 parts by mass of the epoxy resin. A content of 1 part by mass or more effectively accelerates curing. Furthermore, a content of 100 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 60 parts by mass or less, is cost-effective.

[0047] The aforementioned amines may be those commonly known as curing agents or catalysts for epoxy resins, such as aliphatic diamines like ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, trimethylenediamine, hexamethylenediamine, and tetramethylenediamine; aliphatic tertiary amines like N,N-dimethylpropylamine and N,N,N',N'-tetramethylhexamethylenediamine; alicyclic tertiary amines like N-methylpiperidine and N,N'-dimethylpiperazine; benzyldimethylamine; and dimethylamine. Examples include aromatic tertiary amines such as methylphenol and 2,4,6-tris(dimethylaminomethyl)phenol, polyamine epoxy resin adducts produced by reacting epoxy resin with an excess amine, polyamine-ethylene oxide adducts, polyamine-propylene oxide adducts, cyanoethylated polyamines, diamines with a silicon main chain, or dehydration condensates obtained by reacting polyamines with phenols and aldehydes, imidazoles such as 2-ethyl-4-methylimidazole, and modified polyamines.

[0048] As modified polyamines derived from amines, modified diethylenetriamine, modified triethylenetetramine, and modified tetraethylenepentamine are particularly preferred, and among these, modified products obtained by reacting the amino group of triethylenetetramine with a mono- or polyepoxy compound are more preferred. For example, "BB-AMINE 3138" manufactured by BB RESINS SRL is one such example.

[0049] The amines are preferably those with an amine value of 900 to 1400, more preferably 1000 to 1300, and even more preferably 1100 to 1200.

[0050] Furthermore, if the amines are modified polyamines, they are preferably those with an amine value of 1000 to 1300, and more preferably 1100 to 1200.

[0051] The amine value is defined as the number of milligrams of potassium hydroxide equivalent to perchloric acid required to neutralize the total basic nitrogen contained in 1 gram of amine.

[0052] The epoxy resin composition of the present invention preferably has a curing time of 15 minutes or less at 5°C. The curing time of the epoxy resin-containing composition is defined as the gel time when a toothpick (wooden, 2 mm in diameter x 150 mm in length) inserted into the epoxy resin composition becomes immobile. Other measurement conditions are based on the method for determining the pot life of multi-component adhesives described in JIS K 6870:2008.

[0053] [Hardener for epoxy resins] The epoxy resin curing agent of the present invention contains the polymer composition of the present invention.

[0054] [Fast-curing adhesive] The fast-curing adhesive of the present invention contains the polymer composition of the present invention, an epoxy resin, and amines.

[0055] As the amines in the fast-curing adhesive of the present invention, preferred embodiments similar to those in the epoxy resin composition of the present invention can be used.

[0056] In other words, for example, the amine value of the amines in the fast-curing adhesive of the present invention is preferably 1000 to 1300.

[0057] The fast-curing adhesive of the present invention preferably has a curing time of 7 minutes or less at 5°C.

[0058] The fast-curing adhesive of the present invention preferably has an adhesion development time of 12 minutes or less to cold-rolled steel sheets at 8°C. [Examples]

[0059] The present invention will be specifically described below with reference to examples and comparative examples. In the following examples, unless otherwise specified, general reagents purchased from reagent manufacturers were used as raw materials. The following apparatus and methods were used for the analysis.

[0060] [Measurement method] (1) Viscosity The viscosity of the sample at 25°C was measured using a viscometer (U-EII, manufactured by Toki Sangyo Co., Ltd.).

[0061] (2) Mercaptan content The mercaptan content was measured by dissolving the sample in a mixture of toluene and pyridine, adding potassium iodide aqueous solution, and then titrating with an iodine standard solution.

[0062] (3) Content of cationic surfactants The content of cationic surfactants was determined by dissolving the polymer composition in an alcohol solvent, extracting it with an extraction solvent, and analyzing the extracted phase by ion chromatography.

[0063] More specifically, 0.1 g to 1.0 g of the polymer composition was dissolved in 20 ml of n-hexanol, and then 15 ml of 2.5 mM aqueous nitric acid solution was added. After thorough mixing, the solution was separated, and the aqueous phase was analyzed by ion chromatography under the following conditions. The concentration of the obtained aqueous phase was corrected by the partition rate, and the content of the cationic surfactant in the polymer composition was calculated.

[0064] (Ion chromatography analysis conditions) Column: “Shodex (Registered trademark) "IC YK-421 Mobile phase: 2.5 mM nitric acid aqueous solution / acetonitrile (volume ratio 8 / 2) Flow rate: 1.0ml / min Temperature: 40℃ Detector: Electrical conductivity detector.

[0065] (4) Curing time at 5°C 8.0 g of the polymer composition of each example and comparative example, 10.0 g of bisphenol A type epoxy resin ("jER828" manufactured by Mitsubishi Chemical Corporation) with an epoxy equivalent of 184-194, and 1.0 g of "BB-AMINE 3138" manufactured by BB RESINS SRL with an amine value of 1150 were mixed to prepare the epoxy resin composition.

[0066] The curing time was defined as the gel time at which a toothpick (wooden, 2 mm in diameter x 150 mm in length) inserted into the epoxy resin composition became immobile. Specifically, under conditions of 5°C, a toothpick was inserted into the epoxy resin composition obtained by mixing the raw materials for each example, and the point at which the toothpick became immobile was defined as the gel time. The gel time was measured from the start of pre-mixing and included the degassing and mixing time. Other measurement conditions were based on the method for determining the pot life of multi-component adhesives described in JIS K 6870:2008.

[0067] (5) Time to develop adhesive strength at 8°C The time it took for adhesive strength to develop at low temperatures was measured by actually bonding two steel plates together in a low-temperature environment. Specifically, at 8°C, an epoxy resin composition was applied to a 25mm square area of ​​a 1.6mm thick x 25mm wide x 100mm long cold-rolled steel plate (SPCC-SD (general-purpose, standard temper, dull finish) as specified in JIS G3141:2017), and another cold-rolled steel plate of the same size was bonded to it. The time it took for the two cold-rolled steel plates to bond and become immobile was defined as the time for adhesive strength to develop.

[0068] [Example of combination] (Polyether polymer 1 having thiol groups) 500 g of trifunctional polypropylene glycol (OH value 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin and 3.0 g of stannic chloride pentahydrate were charged into a 3 liter reaction vessel. The temperature was raised to 50°C, and 496 g of epichlorohydrin was added dropwise over 1 hour. After addition, the mixture was stirred at 80°C for 2 hours. 1227 g of N,N-dimethylformamide was added to the resulting halogen-terminated polyether polymer and mixed. Then, 634 g of sodium hydrosulfide (concentration 48%) was added and the mixture was purged with nitrogen. The mixture was then stirred at 80°C for 2 hours. Finally, the salt and N,N-dimethylformamide were removed to obtain a colorless, transparent liquid polyether polymer 1 having thiol groups.

[0069] The mercaptan content of polyether polymer 1, which contains thiol groups, was 13.0% by mass, and its viscosity at 25°C was 13.6 Pa·s.

[0070] (Polyether polymer 2 having thiol groups) 500 g of trifunctional polypropylene glycol (OH value 400 mg KOH / polypropylene glycol) obtained by adding propylene oxide to trimethylolpropane and 3.7 g of a 50% aqueous solution of stannous chloride were charged into a 3 liter reaction vessel. The temperature was raised to 50°C, and 462 g of epichlorohydrin was added dropwise over 1 hour. After addition, the mixture was stirred at 80°C for 2 hours. 1227 g of N,N-dimethylformamide was added to the resulting halogen-terminated polyether polymer and mixed. Then, 589 g of sodium hydrosulfide (concentration 48%) was added. The mixture was then stirred at 80°C for 2 hours. Finally, the salt and N,N-dimethylformamide were removed to obtain a colorless, transparent liquid polyether polymer 2 having thiol groups.

[0071] The mercaptan content of polyether polymer 2 having thiol groups was 11.4% by mass, and its viscosity at 25°C was 10.2 Pa·s.

[0072] [Example 1] A polymer composition was obtained by weighing 0.42 g of tetraethylammonium bromide onto 100 g of thiol group-containing polyether polymer 1 and mixing them at 80°C for 1 hour.

[0073] The tetraethylammonium bromide content in the polymer composition was 0.4% by mass. The curing time of the polymer composition at 5°C was 6.8 minutes.

[0074] [Example 2] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with 0.64 g of tetrabutylammonium bromide.

[0075] The tetrabutylammonium bromide content in the polymer composition was 0.6% by mass. The curing time of the polymer composition at 5°C was 5.9 minutes. The time it took for the polymer composition to develop adhesive strength at 8°C was 11.7 minutes.

[0076] [Example 3] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with 0.74 g of tetrabutylammonium iodide.

[0077] The tetrabutylammonium iodide content in the polymer composition was 0.7% by mass. The curing time of the polymer composition at 5°C was 6.2 minutes.

[0078] [Example 4] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with 0.68 g of tetrabutylammonium sulfate.

[0079] The polymer composition contained 0.7% by mass of tetrabutylammonium hydrogen sulfate. The curing time of the polymer composition at 5°C was 5.5 minutes.

[0080] [Example 5] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with 0.68 g of tetrabutylphosphonium bromide.

[0081] The polymer composition contained 0.7% by mass of tetrabutylammonium hydrogen sulfate. The curing time of the polymer composition at 5°C was 6.0 minutes. The time to achieve adhesive strength of the polymer composition at 8°C was 11.4 minutes.

[0082] [Example 6] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with 0.46 g of benzyltriethylammonium chloride.

[0083] The benzyltriethylammonium chloride content in the polymer composition was 0.5% by mass. The curing time of the polymer composition at 5°C was 5.3 minutes. The time to achieve adhesive strength of the polymer composition at 8°C was 10.9 minutes.

[0084] [Example 7] A polymer composition was obtained in the same manner as in Example 1, except that tetraethylammonium bromide was replaced with tributylmethylammonium chloride 0.47.

[0085] The tributylmethylammonium chloride content in the polymer composition was 0.5% by mass. The curing time of the polymer composition at 5°C was 6.0 minutes.

[0086] [Comparative Example 1] A polymer composition was obtained by using polyether polymer 1 having thiol groups without adding anything to it.

[0087] No cationic surfactants were detected in the polymer composition. The curing time of the polymer composition at 5°C was 8.1 minutes. The time it took for the polymer composition to develop adhesive strength at 8°C was 16.2 minutes.

[0088] [Comparative Example 2] A polymer composition was obtained using polyether polymer 2 having thiol groups without adding anything to it.

[0089] No cationic surfactants were detected in the polymer composition. Furthermore, the curing time of the polymer composition at 5°C was 17.3 minutes. The time it took for the polymer composition to develop adhesive strength at a lower temperature of 8°C was 29.0 minutes.

[0090] [Comparative Example 3] A commercially available polyether polymer containing thiol groups, trade name "CupCure 3-800," was used as a polymer composition without any additives.

[0091] No cationic surfactants were detected in the polymer composition. The curing time of the polymer composition at 5°C was 14.0 minutes. The time it took for the polymer composition to develop adhesive strength at 8°C was 24.0 minutes.

[0092] [Table 1]

[0093] Table 1 summarizes the curing times at 5°C for Examples 1-7 and Comparative Examples 1-3. The epoxy resin compositions using the polymer compositions of Examples 1-7 had a curing time of 7 minutes or less at 5°C.

[0094] [Table 2]

[0095] Table 2 summarizes the adhesion development time at 8°C and the curing time at 5°C for Examples 2, 5, and 6, and Comparative Examples 1-3. The epoxy resin compositions using the polymer compositions of Examples 2, 5, and 6 had an adhesion development time of 12 minutes or less at 8°C. As shown in Table 2, there is a phase relationship between the adhesion development time at 8°C and the curing time at 5°C, and it was found that epoxy resin compositions with a faster curing time at 5°C exhibit faster adhesion to cold-rolled steel sheets at the low temperature of 8°C.

Claims

1. A polymer composition comprising a polyether polymer having thiol groups, wherein the polyether polymer having thiol groups has a polyether portion represented by the following chemical formula (1) in its main chain and a structural unit represented by the following formula (2) at its terminal, the thiol group content of the polyether polymer having thiol groups is 8% by mass or more, and the polymer composition further comprises a cationic surfactant. R １ [-(R)] ２ O) ｎ ] ｍ — …Formula (1) However, R １ R is a residue obtained by removing a hydrogen atom from a polyhydric amine or polyhydric alcohol with 10 or fewer carbon atoms, ２ is an alkylene group having 2 to 6 carbon atoms, where n is 1 to 200 and m is 2 to 8. -CH ２ CH(OH)CH ２ -SH... Formula (2)

2. The polymer composition according to claim 1, wherein the thiol group content of the polyether polymer having thiol groups is 8 to 16% by mass.

3. The polymer composition according to claim 1 or 2, wherein the cationic surfactant is a quaternary ammonium salt or a quaternary phosphonium salt.

4. The polymer composition according to claim 1 or 2, wherein the content of the cationic surfactant is 0.01 to 5.0% by mass.

5. An epoxy resin composition comprising the polymer composition according to claim 1 or 2 and an epoxy resin, wherein the content of the epoxy resin is 100 to 600 parts by mass per 100 parts by mass of the polyether polymer having thiol groups.

6. The epoxy resin composition according to claim 5, comprising 1 to 60 parts by mass of amines per 100 parts by mass of the epoxy resin.

7. The epoxy resin composition according to claim 6, wherein the amines are modified amines having three or more amino groups in one molecule.

8. The epoxy resin composition according to claim 6, wherein the amine value of the amines is 1000 to 1300.

9. The epoxy resin composition according to claim 6, wherein the curing time at 5°C is 7 minutes or less.

10. A curing agent for epoxy resins, comprising the polymer composition described in claim 1 or 2.

11. A fast-curing adhesive comprising the polymer composition, epoxy resin, and amines described in claim 1 or 2.

12. The fast-curing adhesive according to claim 11, wherein the curing time at 5°C is 7 minutes or less.

13. The fast-curing adhesive according to claim 11, wherein the time required for adhesion to cold-rolled steel sheets at 8°C is 12 minutes or less.

14. The fast-curing adhesive according to claim 11, wherein the amine value of the amines is 1000 to 1300.

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