Polymer composition, epoxy resin composition, curing agent for epoxy resin, and fast-curing adhesive

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

Polymer composition, epoxy resin composition, curing agent for epoxy resin, and fast-curing adhesive

[0001] The present invention relates to an epoxy resin composition, a curing agent for epoxy resins, and a fast-curing adhesive.

[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 skeleton in the main chain and three or more thiol groups per molecule, cure in about 2 to 10 minutes at room temperature. Epoxy adhesives that use a polymercaptan-based curing agent, a compound with a polyether skeleton in the main chain and three or more thiol groups per molecule, cure quickly at room temperature, but have difficulty curing at relatively low temperatures below 15°C, and have had the problem of slow curing in winter and cold environments.

[0006] Therefore, there is a need for an epoxy adhesive that has a sufficiently fast curing rate even in low temperature environments.

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

[0008] An 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 a low-temperature environment, a low viscosity, and good stability and adhesiveness.

[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 a low-temperature environment, a low viscosity, and good stability and adhesiveness.

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

[0011] The present invention also relates to an epoxy resin composition comprising 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 a thiol group.

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

[0013] The present invention also relates to a fast-curing adhesive containing the polymer composition of the present invention, an epoxy resin, and an amine.

[0014] The polymer composition of the present invention can be used as a curing agent for epoxy resins, which has a high curing rate even in a low temperature environment, a low viscosity, and good stability and adhesiveness.

[0015] Furthermore, the epoxy resin composition of the present invention has a high curing rate even in a low temperature environment, and has low viscosity, good stability, and adhesiveness.

[0016] [Polyether Polymer Having Thiol Groups] The polymer composition of the present invention contains a polyether polymer having thiol groups.

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

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

[0019] 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.

[0020] 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, and isobutylene.

[0021] n is an integer of 1 to 200, preferably 1 to 100. m is an integer of 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 its terminal: —CH ２ CH(OH)CH ２ -SH Formula (2) The structural unit represented by formula (2) can be obtained preferably by reacting a halogen-terminated polyether polymer obtained by adding epihalohydrin with an alkali hydrosulfide and / or alkali polysulfide in a polar solvent.

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

[0024] To synthesize the polyether polymer having the thiol group, the polyol (a) has a chemical structure represented by the following general formula (3): １ [-(R ２ O) ｎ ] ｍ ... (3) 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 1 to 200, and m is 2 to 8.

[0025] Examples of the polyol (a) include polyhydric amines or polyhydric alcohols to which ethylene oxide, propylene oxide, tetrahydrofuran, etc. are added. 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, more preferably 200 to 3,000.

[0027] The thiol group-containing polyether polymer 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 a thiol group is preferably 9 to 17 Pa·s, and more preferably 12 to 14 Pa·s.

[0029] [Cationic Surfactant] The polymer composition of the present invention further contains a cationic surfactant. The inclusion of the cationic surfactant accelerates the reaction, allowing the composition to exhibit rapid curing properties even in a low-temperature environment.

[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, tetradecyltrimethyl ... Preferred are 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, tetradecyltrimethylphosphonium bromide, Preferred are tetrabutylphosphonium bromide, tetra n-propylphosphonium bromide, tetraoctylphosphonium bromide, tetrabutylphosphonium iodide, tetraethylphosphonium iodide, tetra n-propylphosphonium iodide, trimethylphenylphosphonium iodide, tetrabutylphosphonium hydrogen sulfate, benzyltrimethylphosphonium hydroxide, phenyltrimethylphosphonium hydroxide, tetrabutylphosphonium hydroxide, tetraethylphosphonium hydroxide, tetrapropylphosphonium hydroxide, tetrabutylphosphonium hydrogen sulfate, tetrabutylphosphonium tetrafluoroborate, and the like.

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

[0034] As the cationic surfactant, tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate, tetrabutylphosphonium bromide, tetraoctylammonium bromide, benzyltriethylammonium chloride, and methyltributylammonium chloride are more preferred.

[0035] The cationic surfactants may be used alone or 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 rate 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 timing. 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 for synthesizing the polyether polymer having thiol groups. It may also be added during the reaction for synthesizing the polyether polymer having thiol groups. Regardless of the timing of addition, the same effect can be obtained as long as the composition contains a cationic surfactant component.

[0038] In the polymer composition of the present invention, the thiol group-containing polyether polymer and the cationic surfactant may be dissolved in a solvent, which improves the coatability of the polymer composition.

[0039] As the solvent, an alcohol-based solvent is preferably used. From the viewpoint that the polymer composition can be distilled off by slight heating after being applied to a substrate or the like, alcohols with low boiling points are preferred, and in particular, for example, methanol, ethanol, isopropanol, n-butanol, t-butanol, n-heptanol, n-hexanol, etc. are preferred because they have excellent compatibility with the polyether polymer having a thiol group and the cationic surfactant. Among them, methanol and ethanol, which have low molecular weights, are more preferred.

[0040] [Epoxy Resin Curing Agent] The polymer composition of the present invention is suitably used as an epoxy resin curing agent, that is, the epoxy resin curing agent 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 of the present invention and an epoxy resin.

[0042] Examples of the epoxy resin 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.).

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

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

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

[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 can effectively accelerate 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 advantageous in terms of cost.

[0047] The amines may be those known as ordinary curing agents or catalysts for epoxy resins, for example, 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; dimethylamine; Examples of the polyamine include aromatic tertiary amines such as 2-ethyl-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2,4,6-tris(dimethylaminomethyl)phenol; 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; 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 made from amines, modified products of diethylenetriamine, modified products of triethylenetetramine, modified products of tetraethylenepentamine, etc. 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 can be mentioned.

[0049] The amines preferably have an amine value of 900 to 1,400, more preferably 1,000 to 1,300, and even more preferably 1,100 to 1,200.

[0050] When the amine is a modified polyamine, the amine value is preferably 1,000 to 1,300, more preferably 1,100 to 1,200.

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

[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 wooden toothpick (2 mm diameter x 150 mm length) is inserted into the epoxy resin composition and no longer moves. Other measurement conditions are based on the method for determining the pot life of multi-component adhesives described in JIS K 6870:2008.

[0053] [Epoxy Resin Curing Agent] 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 an amine.

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

[0056] That is, for example, the amine value of the amines in the fast-curing adhesive of the present invention is preferably 1,000 to 1,300.

[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 adhesive strength development time to a cold-rolled steel sheet at 8°C of 12 minutes or less.

[0059] 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.

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

[0061] (2) Mercaptan Content A sample was dissolved in a mixed solution of toluene and pyridine, and an aqueous potassium iodide solution was added. The mercaptan content was measured by titration with an iodine standard solution.

[0062] (3) Content of Cationic Surfactant The content of cationic surfactant 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 a 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 aqueous phase was corrected by the distribution coefficient, and the content of the cationic surfactant in the polymer composition was calculated.

[0064] (Conditions for ion chromatography analysis) Column: "Shodex" IC YK-421 Mobile phase: 2.5 mM aqueous nitric acid solution / acetonitrile (volume ratio 8 / 2) Flow rate: 1.0 ml / min Temperature: 40°C Detector: electrical conductivity detector.

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

[0066] The gel time at which a toothpick (wooden, 2 mm diameter x 150 mm length) inserted into the epoxy resin composition no longer moves was defined as the curing time. Specifically, a toothpick was inserted into the epoxy resin composition obtained by mixing the raw materials according to each example at 5°C, and the gel time was determined as the point at which the toothpick no longer moves. 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 pot life of multi-component adhesives described in JIS K 6870:2008.

[0067] (5) Adhesion Strength Development Time at 8°C Two steel plates were actually bonded together in a low-temperature environment, and the adhesion strength development time at low temperatures was measured. Specifically, an epoxy resin composition was applied to a 25 mm square area of ​​a cold-rolled steel plate (SPCC-SD (general-purpose, standard temper, dull finish) specified in JIS G3141:2017) measuring 1.6 mm in thickness, 25 mm in width, and 100 mm in length in an 8°C environment, and another cold-rolled steel plate of the same size was bonded to it. The time until the two cold-rolled steel plates were bonded together and could no longer move was defined as the adhesion strength development time.

[0068] [Synthesis Example] (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, heated to 50°C, and 496 g of epichlorohydrin was added dropwise over 1 hour. After the dropwise addition, the mixture was stirred at 80°C for 2 hours. 1227 g of N,N-dimethylformamide was added to the obtained halogen-terminated polyether polymer and mixed. 634 g of sodium hydrosulfide (concentration 48%) was then added and the atmosphere was purged with nitrogen. The mixture was then stirred at 80°C for 2 hours. The salt and N,N-dimethylformamide were then removed to obtain a colorless, transparent liquid, polyether polymer 1 having thiol groups.

[0069] The mercaptan content of the thiol group-containing polyether polymer 1 was 13.0% by mass, and the 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 stannic chloride were charged into a 3-liter reaction vessel, heated to 50°C, and 462 g of epichlorohydrin was added dropwise over 1 hour. After the dropwise addition, the mixture was stirred at 80°C for 2 hours. 1227 g of N,N-dimethylformamide was added to the obtained halogen-terminated polyether polymer and mixed. 589 g of sodium hydrosulfide (concentration 48%) was then added. The mixture was then stirred at 80°C for 2 hours. The salt and N,N-dimethylformamide were then removed to obtain a colorless, transparent liquid, polyether polymer 2 having thiol groups.

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

[0072] Example 1 0.42 g of tetraethylammonium bromide was weighed out and mixed with 100 g of thiol group-containing polyether polymer 1 at 80° C. for 1 hour to obtain a polymer composition.

[0073] The content of tetraethylammonium bromide in the polymer composition was 0.4% by mass, and 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 0.64 g of tetrabutylammonium bromide was used instead of tetraethylammonium bromide.

[0075] The content of tetrabutylammonium bromide in the polymer composition was 0.6% by mass. The curing time of the polymer composition at 5°C was 5.9 minutes. The adhesive strength development time of the polymer composition 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 changed to 0.74 g of tetrabutylammonium iodide.

[0077] The content of tetrabutylammonium iodide in the polymer composition was 0.7% by mass, and 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 0.68 g of tetrabutylammonium sulfate was used instead of tetraethylammonium bromide.

[0079] The content of tetrabutylammonium hydrogen sulfate in the polymer composition was 0.7% by mass, and 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 0.68 g of tetrabutylphosphonium bromide was used instead of tetraethylammonium bromide.

[0081] The content of tetrabutylammonium hydrogen sulfate in the polymer composition was 0.7% by mass. The curing time of the polymer composition at 5°C was 6.0 minutes. The adhesive strength development time 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 changed to 0.46 g of benzyltriethylammonium chloride.

[0083] The content of benzyltriethylammonium chloride in the polymer composition was 0.5% by mass. The curing time of the polymer composition at 5°C was 5.3 minutes. The adhesive strength development time 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 changed to 0.47% tributylmethylammonium chloride.

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

[0086] Comparative Example 1 A polymer composition was prepared by adding nothing to the thiol group-containing polyether polymer 1.

[0087] No cationic surfactant was detected in the polymer composition. The curing time of the polymer composition at 5°C was 8.1 minutes. The adhesive strength development time of the polymer composition at 8°C was 16.2 minutes.

[0088] Comparative Example 2 A polymer composition was prepared without adding anything to the thiol group-containing polyether polymer 2.

[0089] No cationic surfactant was detected in the polymer composition. The curing time of the polymer composition at 5°C was 17.3 minutes. The adhesive strength development time of the polymer composition at a low temperature of 8°C was 29.0 minutes.

[0090] Comparative Example 3 A commercially available polyether polymer having a thiol group, trade name "Cupcure 3-800," was used as it was to prepare a polymer composition without adding anything.

[0091] No cationic surfactant was detected in the polymer composition. The curing time of the polymer composition at 5°C was 14.0 minutes. The adhesive strength development time of the polymer composition at 8°C was 24.0 minutes.

[0092]

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

[0094]

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

Claims

1. A polymer composition comprising a polyether polymer having a thiol group, the polyether polymer having a thiol group having a polyether moiety 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 the thiol group is 8 mass% or more, and the polymer composition further comprises a cationic surfactant. R １ [-(R ２ O) ｎ ] ｍ - ...Formula (1) However, R １ is a residue obtained by removing a hydrogen atom from a polyhydric amine or polyhydric alcohol having 10 or less carbon atoms, R ２ is an alkylene group having 2 to 6 carbon atoms, n is 1 to 200, and m is 2 to 8. -CH ２ CH(OH)CH ２ -SH... Formula (2)

2. 2. The polymer composition according to claim 1, wherein the thiol group-containing polyether polymer has a thiol group content of 8 to 16% by mass.

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

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

5. 3. 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 a thiol group.

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

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

8. 7. The epoxy resin composition according to claim 6, wherein the amines have an amine value of 1,000 to 1,300.

9. 7. The epoxy resin composition according to claim 6, having a curing time of 7 minutes or less at 5°C.

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

11. A fast-curing adhesive comprising the polymer composition according to claim 1 or 2, an epoxy resin and an amine.

12. 12. The fast-curing adhesive according to claim 11, having a curing time of 7 minutes or less at 5°C.

13. 12. The fast-curing adhesive according to claim 11, which has an adhesive strength development time to cold-rolled steel sheet of 12 minutes or less at 8°C.

14. The fast-curing adhesive according to claim 11, wherein the amines have an amine value of 1,000 to 1,300.