Method for producing thiol group-containing polyether polymers

Abstract

The present invention addresses the problem of providing a production method of a polyether polymer having an increased thiol group content and a reduced halogen content by suppressing a side reaction without adding hydrogen sulfide.　The present invention pertains to a production method of a thiol group-containing polyether polymer, said method comprising reacting a terminal halogenated polyether polymer with a metal salt of hydrogen sulfide by a substitution reaction to thereby produce the thiol group-containing polyether polymer, wherein: the substitution reaction is carried out in a closed system; the terminal halogenated polyether polymer is fed into the closed system in an amount of 20 vol% or more relative to the volume of the closed system; and the metal salt of hydrogen sulfide is fed into the closed system as an aqueous solution having a concentration thereof of 25 mass% or more.

Description

[Technical Field]

[0001] The present invention relates to the technical field concerning epoxy resin curing agents, and more particularly to a method for producing thiol group-containing polyether polymers. [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 polythiol-based curing agents are used by mixing them with epoxy resin and a tertiary amine, which is a curing accelerator.

[0005] As a method for preparing the polythiol-based curing agent described above, for example, a method is known in which a chlorinated polyether polyol is prepared from a polyether polyol and epichlorohydrin, sodium hydrogen sulfide is added to it, and glycerin is used as a catalyst to prepare the polythiol-based curing agent (see Patent Document 2). In the manufacturing method described in Patent Document 2, hydrogen sulfide is used as a protective gas to suppress side reactions, taking into consideration the chemical reaction equilibrium. However, hydrogen sulfide is a toxic gas that acts on the brain and nerves and can lead to death at concentrations of 700 ppm or higher, and in addition, it is a high-pressure flammable and combustible gas, so it is subject to the regulations of the High-Pressure Gas Safety Act. Therefore, handling hydrogen sulfide requires considerable cost and effort to ensure the safety of workers as well as the safety of manufacturing and ancillary equipment. Furthermore, the resulting polythiol-based curing agent has a large amount of residual chlorine in the product, and in some cases it cannot be used for electronic material applications that require the absence of halogens or halogen compounds.

[0006] Therefore, there was a need for a method of producing polythiols that offered high operational safety, low halogen content, low viscosity for easy handling, and a high thiol group content. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 108822011 Specification [Patent Document 2] Chinese Patent Application Publication No. 109880075 Specification [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a manufacturing method that suppresses side reactions, increases the thiol group content of the thiol group-containing polyether polymer, reduces the halogen content, and has low viscosity and good handling properties. [Means for solving the problem]

[0009] The present invention relates to a method for producing a thiol group-containing polyether polymer by reacting a terminal halogenated polyether polymer with a hydrogen sulfide metal salt by a substitution reaction, wherein the terminal halogenated polyether polymer has a polyether portion represented by the following general formula (1) in its main chain and a structure represented by the following general formula (2) at its end, the hydrogen sulfide metal salt is represented by the following general formula (3), the thiol group-containing polyether polymer has a polyether portion represented by the following general formula (1) and a structural unit represented by the following formula (4) at its end, the substitution reaction is carried out in a closed system, the terminal halogenated polyether polymer is charged into the closed system in an amount of 20% by volume or more of the volume of the closed system, and the hydrogen sulfide metal salt is charged into the closed system as an aqueous solution with a concentration of 25% by mass or more. R 1 [-(R 2 O) n ] m - (1) In formula (1), R 1 R is a group with a structure 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, n is an integer from 1 to 200, and m is an integer from 2 to 8. -CH2CH(OH)CH2-X (2) In equation (2), X is a halogen atom. M(SH) k (3) In equation (3), M is an alkali metal or alkaline earth metal, and k is an integer between 1 and 2. -CH2CH(OH)CH2-SH (4). [Effects of the Invention]

[0010] In the manufacturing method of the present invention, by carrying out the substitution reaction in a closed system and trapping the by-product hydrogen sulfide gas, side reactions can be suppressed and the thiol group content can be increased without supplying hydrogen sulfide as a protective gas beforehand. Furthermore, since there is no need to add hydrogen sulfide from an external source, hydrogen sulfide transport, storage, and supply facilities are unnecessary, resulting in a low level of risk, and the transportation and storage of raw materials are not subject to the regulations of the High Pressure Gas Safety Act. In addition, by using an aqueous solution with a hydrogen sulfide metal salt concentration of 25% by mass or higher, the halogen content of the thiol group-containing polyether polymer can be reduced, and the viscosity can be lowered, improving handling ease. [Modes for carrying out the invention]

[0011] The present invention provides a method for producing a thiol group-containing polyether polymer by reacting a terminally halogenated polyether polymer with a hydrogen sulfide metal salt through a substitution reaction.

[0012] The present invention provides a method for producing a thiol group-containing polyether polymer, in which the substitution reaction is carried out in a closed system. By doing so, the by-product hydrogen sulfide gas is confined within the closed system, and the side reaction of sulfidation, in which molecules dimerize, is suppressed without supplying hydrogen sulfide from the outside, thereby increasing the thiol group content in the target thiol group-containing polyether polymer.

[0013] Furthermore, it is preferable to confine by-products other than hydrogen sulfide gas within the closed system and not introduce any substances other than hydrogen sulfide after closing the reaction system. Note that venting gas from a pressure regulating valve or the like for pressure control, as described later, is not inconsistent with performing the procedure within the closed system. Examples of reactors include autoclaves, TEM-D type metal reactors manufactured by Pressure Glass Industry Co., Ltd. (TEM-D500M, TEM-D1000M, TEM-D1500M, TEM-D3000MK), TEM-U type reactors (TEM-U1000N), and TEM-V type reactors (TEM-V500).

[0014] The terminal halogenated polyether polymer has a polyether moiety represented by the following general formula (1) in the main chain. R 1 [-(R 2 O) n m - (1).

[0015] In formula (1), R 1 is a group having a structure obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 10 or fewer 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.

[0016] In general formula (1), R 1 is a group having a structure obtained by removing m hydrogen atoms from a polyvalent amine or polyhydric alcohol having 10 or fewer carbon atoms. m is an integer of 2 to 8, preferably 2 to 5.

[0017] Examples of the polyvalent amine include triethanolamine and ethylenediamine.

[0018] Examples of the polyhydric alcohol include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, diglycerin, pentaerythritol, triethanolamine, and sucrose. Among the above polyols, glycerin, trimethylolpropane, and trimethylolethane are particularly preferable.

[0019] The polyvalent amine and the polyhydric alcohol may be used alone or in combination.

[0020] In general formula (1), 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. ​

[0022] The aforementioned terminally halogenated polyether polymer has a structure represented by the following general formula (2) at its end. -CH2CH(OH)CH2-X (2).

[0023] In general formula (2), X is a halogen atom, preferably selected from chlorine, bromine, and iodine. More preferably, it is chlorine.

[0024] The terminal halogenated polyether polymer can be obtained by an addition reaction in which a polyether polyol having a polyether moiety represented by general formula (1) is reacted with an epihalohydrin.

[0025] Examples of the aforementioned polyether polyols include those obtained by adding ethylene oxide, propylene oxide, tetrahydrofuran, etc., to a polyhydric amine or polyhydric alcohol.

[0026] Examples of the aforementioned polyhydric amines include triethanolamine and ethylenediamine.

[0027] Examples of the aforementioned polyhydric alcohols include glycerin, trimethylolpropane, trimethylolethane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, and sucrose.

[0028] These polyhydric amines and polyhydric alcohols may be used individually or in combination.

[0029] Among the polyether polyols, polypropylene glycol obtained by adding propylene oxide to glycerin, trimethylolpropane, trimethylolethane, or pentaerythritol is particularly preferred.

[0030] The molecular weight of the polyether polyol is preferably 200 to 10,000, and more preferably 200 to 1,000.

[0031] Examples of the epihalohydrins mentioned above include epichlorohydrin, epibromohydrin, epiiodohydrin, epifluorohydrin, and β-methylepichlorohydrin. Among these, epichlorohydrin is preferred.

[0032] The amount of the terminal halogenated polyether polymer added is 20% by volume or more of the volume of the closed system. By setting the amount to 20% by volume or more, more preferably 25% by volume or more, and even more preferably 30% by volume or more, the pressure in the closed system is more likely to rise due to the by-product hydrogen sulfide, and the concentration of hydrogen sulfide in the reaction solution increases. This increase in hydrogen sulfide concentration suppresses the side reaction of sulfidation, in which molecules dimerize, and can suppress the increase in viscosity of the product. It is also preferable that the amount added be 70% by volume or less. By doing so, the substitution reaction can be operated safely without sudden pressure changes.

[0033] The aforementioned hydrogen sulfide metal salt is represented by the following general formula (3). M(SH) k (3).

[0034] In general formula (3), M is an alkali metal or alkaline earth metal, such as lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, and barium.

[0035] In general formula (3), k is an integer between 1 and 2.

[0036] Among the aforementioned hydrogen sulfide metal salts, sodium hydrogen sulfide (NaSH) is preferred.

[0037] The hydrogen sulfide metal salt is charged into the closed system as an aqueous solution. The concentration of the hydrogen sulfide metal salt in the aqueous solution is 25% by mass or more. By setting the concentration to 25% by mass or more, preferably 32% by mass or more, and more preferably 40% by mass or more, the halogen content in the target thiol group-containing polyether polymer can be reduced. Furthermore, by setting the concentration to 70% by mass or less, good stirability during the substitution reaction can be maintained, and the viscosity of the product can be lowered to improve handling.

[0038] In electronic materials applications, products, components, and materials are required to be free of halogens and halogen compounds. International standards such as IEC (International Electrotechnical Commission) 61249-2-21, IPC (International Electrical Circuit Manufacturers Association) 4101B, and the Japan Electronics Circuit Manufacturers Association (JPCA) define a halogen-free threshold, requiring a chlorine (Cl) content of 0.09% by mass (900 ppm) or less. The thiol group-containing polyether polymer obtained by the manufacturing method of the present invention can have residual halogens reduced to 900 ppm or less, preferably 600 ppm or less, and more preferably 300 ppm or less, by using an aqueous solution with a hydrogen sulfide metal salt concentration of 25% by mass or more.

[0039] The amount of hydrogen sulfide metal salt added is preferably 1.0 to 3.0 mol times the molar amount of halogen in the terminal halogenated polyether polymer. By adding 1.0 mol or more, more preferably 1.1 mol or more, the substitution reaction proceeds sufficiently, and a thiol group-containing polyether polymer with a low halogen content can be obtained. On the other hand, by adding 3.0 mol or less, more preferably 2.0 mol or less, raw material costs can be reduced, which is economically advantageous.

[0040] A catalyst may be used in the substitution reaction. When such a catalyst is used, the reaction rate will be faster and productivity can be expected to improve. Examples of such catalysts include phase transfer catalysts such as tetrabutylammonium bromide (TBAB), tributylmethylammonium chloride (MTBAC), benzyltriethylammonium chloride (BTEAC), and tetrabutylphosphonium bromide (TBPB). Among these, TBAB and MTBAC are preferred.

[0041] The amount of catalyst used is preferably 0.005 to 0.2 mol times, and more preferably 0.01 to 0.1 mol times, relative to the molar amount of halogen in the terminal halogenated polyether polymer.

[0042] A solvent may be used in the substitution reaction. Examples of such solvents 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.

[0043] However, when water is used as the solvent for the substitution reaction, the amount added should be limited to an amount such that the concentration of the hydrogen sulfide metal salt, when mixed with the aqueous solution of the hydrogen sulfide metal salt, does not fall below 25% by mass.

[0044] When using the aforementioned solvent, the amount used is preferably 0.2 to 5.0 times the mass of the terminal halogenated polyether polymer, and more preferably 1.0 to 3.0 times the mass.

[0045] The reaction temperature for the substitution reaction is preferably 60 to 120°C, more preferably 70 to 100°C. By setting the reaction temperature within this range, the halogen content of the thiol group-containing polyether polymer can be reduced, and the viscosity can be lowered to improve handling.

[0046] The reaction time for the substitution reaction 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 thiol group-containing polyether polymer can be reduced, and efficient production can be ensured.

[0047] Furthermore, the gauge pressure in the closed system during the substitution reaction is preferably controlled to be between 0.01 and 5.0 MPa, more preferably between 0.1 and 3.0 MPa. By keeping the gauge pressure within this range, the halogen content of the thiol group-containing polyether polymer can be reduced, and the viscosity can be lowered to improve handling.

[0048] The thiol group-containing polyether polymer obtained by the substitution reaction has a polyether moiety represented by the general formula (1) and a structural unit represented by the following formula (4) at its terminal. -CH2CH(OH)CH2-SH (4).

[0049] In the thiol group-containing polyether polymer, the thiol group content is preferably 8% by mass or more, more preferably 8 to 16% by mass, and even more preferably 9 to 15% by mass. By keeping the thiol group content within this range, a viscosity that is less prone to dripping during use and has good handling properties can be achieved.

[0050] In the present invention, the thiol group content can be determined by iodine titration, in which the sample is dissolved in a mixed solution of toluene and pyridine, an aqueous potassium iodide solution is added, and then the sample is titrated with an iodine standard solution. Such a method is widely known and is disclosed, for example, in paragraph 0079 of Japanese Patent Application Publication No. 2012-153794.

[0051] Furthermore, the viscosity of the thiol group-containing polyether polymer is preferably 9 to 17 Pa·s, more preferably 10 to 14 Pa·s. By keeping the viscosity within this range, dripping during use can be reduced, and handling can be improved.

[0052] In the present invention, the viscosity of the thiol group-containing polyether polymer can be measured using a viscometer U-EII manufactured by Toki Sangyo Co., Ltd. [Examples]

[0053] 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. Furthermore, the properties of the thiol group-containing polyether polymer were evaluated by the following method.

[0054] [Measurement method] (1) Viscosity The viscosity of the thiol group-containing polyether polymer was measured at 25°C using a viscometer (U-EII, manufactured by Toki Sangyo Co., Ltd.).

[0055] (2) Thiol group content The weighed thiol group-containing polyether polymer was dissolved in a mixed solution of toluene and pyridine, and after adding potassium iodide aqueous solution, the mixture was titrated with an iodine standard solution.

[0056] (3) Chlorine content The chlorine content in the thiol group-containing polyether polymer was measured using an elemental analyzer (NSX-2100, manufactured by Mitsubishi Chemical Analytec Co., Ltd.).

[0057] [Example 1] 200 g of trifunctional polypropylene glycol (trifunctional PPG) (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (abbreviated as "GLYC" in the table) (1.8 mol as hydroxyl groups) and 3.7 g of aqueous solution of stannous chloride (SnCl4) (concentration 50% by mass) (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel, the temperature was raised to 50°C, and 183 g of epichlorohydrin (EpCH) (1.1 mol times the hydroxyl groups) was added dropwise over 1 hour. Then, the mixture was stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0058] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.1 L autoclave (TEM-U1000N), and then 483 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 46% by mass) (2.0 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 31 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0059] The obtained thiol group-containing polyether polymer had a thiol group content of 12.7% by mass, a viscosity of 9.3 Pa·s, and a chlorine content of 50 ppm.

[0060] [Example 2] A colorless, transparent liquid thiol group-containing polyether polymer was obtained in the same manner as in Example 1, except that the internal pressure during the substitution reaction was controlled to a maximum of 0.2 MPa.

[0061] The obtained thiol group-containing polyether polymer had a thiol group content of 12.0% by mass, a viscosity of 10.0 Pa·s, and a chlorine content of 110 ppm.

[0062] [Example 3] A colorless, transparent liquid thiol group-containing polyether polymer was obtained in the same manner as in Example 1, except that the amount of sodium hydrogen sulfide aqueous solution (NaSH concentration 46% by mass) used was 290 g (1.2 mol times the amount of chlorine in the terminal halogenated polyether polymer).

[0063] The obtained thiol group-containing polyether polymer had a thiol group content of 12.0% by mass, a viscosity of 10.4 Pa·s, and a chlorine content of 500 ppm.

[0064] [Example 4] 300 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (2.7 mol as hydroxyl groups) and 5.6 g of 50% by mass aqueous solution of stannous chloride (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel, the temperature was raised to 50°C, and 300 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. Then, the mixture was stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0065] The entire volume of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 791 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 46% by mass) (2.0 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 31%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0066] The obtained thiol group-containing polyether polymer had a thiol group content of 13.0% by mass, a viscosity of 13.0 Pa·s, and a chlorine content of 150 ppm.

[0067] [Example 5] 300 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (2.7 mol as hydroxyl groups) and 5.6 g of 50% by mass aqueous solution of stannous chloride (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel, the temperature was raised to 50°C, and 300 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. Then, the mixture was stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0068] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 5 g of TBAB (0.005 mol times the amount of chlorine in the terminally halogenated polyether polymer) and 791 g of sodium hydrogen sulfide aqueous solution (NaSH concentration 46% by mass) (2.0 mol times the amount of chlorine in the terminally halogenated polyether polymer) were added as phase transfer catalysts. At this time, the proportion of the terminally halogenated polyether polymer in the closed system (reaction vessel) was 31 vol%. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0069] The obtained thiol group-containing polyether polymer had a thiol group content of 13.0% by mass, a viscosity of 12.9 Pa·s, and a chlorine content of 100 ppm.

[0070] [Example 6] A colorless, transparent liquid thiol group-containing polyether polymer was obtained in the same manner as in Example 5, except that 52 g of TBAB (0.05 mol times the amount of chlorine in the terminally halogenated polyether polymer) was used as the phase transfer catalyst.

[0071] The obtained thiol group-containing polyether polymer had a thiol group content of 13.2% by mass, a viscosity of 12.7 Pa·s, and a chlorine content of 70 ppm.

[0072] The conditions and measurement results for Examples 1 to 6 described above are summarized in Table 1.

[0073] [Table 1]

[0074] [Example 7] 113 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (1.0 mol as hydroxyl groups) and 2.1 g of 50% by mass aqueous stannous chloride solution (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel. The temperature was raised to 50°C, and 113 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0075] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 0.5 L autoclave (TEM-V500), and then 171 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 48% by mass) (1.2 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 39 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0076] The obtained thiol group-containing polyether polymer had a thiol group content of 13.5% by mass, a viscosity of 10.5 Pa·s, and a chlorine content of 500 ppm.

[0077] [Example 8] 190 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (1.7 mol as hydroxyl groups) and 1.8 g of 50% by mass aqueous stannous chloride solution (0.2 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel. The temperature was raised to 50°C, and 174 g of epichlorohydrin (1.1 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0078] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 264 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 48% by mass) (1.2 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 20% by volume. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 95°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. After that, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0079] The obtained thiol group-containing polyether polymer had a thiol group content of 11.7% by mass, a viscosity of 12.9 Pa·s, and a chlorine content of 400 ppm.

[0080] [Example 9] 300 g of trifunctional polypropylene glycol (OH value: 400 mg KOH / polypropylene glycol) obtained by adding propylene oxide to trimethylolpropane (TMP) (2.1 mol as hydroxyl groups) and 2.2 g of 50% by mass aqueous stannic chloride solution (0.2 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel, the temperature was raised to 50°C, and 237 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. Then, the mixture was stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0081] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 625 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 46% by mass) (2.0 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 29 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 95°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.5 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0082] The obtained thiol group-containing polyether polymer had a thiol group content of 11.4% by mass, a viscosity of 10.2 Pa·s (25°C), and a chlorine content of 150 ppm.

[0083] [Comparative Example 1] 300 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (2.7 mol as hydroxyl groups) and 5.6 g of 50% by mass aqueous stannous chloride solution (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel. The temperature was raised to 50°C, and 275 g of epichlorohydrin (1.1 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0084] Next, 725 g of an aqueous sodium hydrogen sulfide solution (46% by mass concentration) (2.0 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. No phase transfer catalyst (PTC) was used. The reaction was started at 90°C under atmospheric pressure in an open system. Side reactions proceeded, resulting in an extremely low thiol group content, and the polymer gelled due to high viscosity during the reaction; therefore, a liquid polymer could not be obtained.

[0085] [Comparative Example 2] 150 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (1.35 mol as hydroxyl groups) and 2.8 g of 50% by mass aqueous stannous chloride solution (0.4 mol% of the hydroxyl groups) were charged into a 0.5 L reaction vessel. The temperature was raised to 50°C, and 138 g of epichlorohydrin (1.1 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0086] The obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 501 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 20% by mass) (1.2 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 16 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.4 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0087] The obtained thiol group-containing polyether polymer had a thiol group content of 11.3% by mass, a viscosity of 12.9 Pa·s, and a chlorine content of 3800 ppm.

[0088] [Comparative Example 3] 156 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (1.4 mol as hydroxyl groups) and 1.5 g of 50% by mass aqueous stannous chloride solution (0.2 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel. The temperature was raised to 50°C, and 156 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0089] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 247 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 46% by mass) (1.2 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 17 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.2 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0090] The obtained thiol group-containing polyether polymer had a thiol group content of 11.3% by mass, a viscosity of 29.8 Pa·s, and a chlorine content of 800 ppm.

[0091] [Comparative Example 4] 230 g of trifunctional polypropylene glycol (OH value: 510 mg KOH / polypropylene glycol) obtained by adding propylene oxide to glycerin (2.1 mol as hydroxyl groups) and 4.3 g of 50% by mass aqueous stannic chloride solution (0.4 mol% of the hydroxyl groups) were charged into a 1 L reaction vessel. The temperature was raised to 50°C, and 230 g of epichlorohydrin (1.2 mol times the hydroxyl groups) was added dropwise over 1 hour. The mixture was then stirred at 80°C for 2 hours to obtain a terminally halogenated polyether polymer.

[0092] The entire amount of the obtained terminally halogenated polyether polymer was transferred to a 1.6 L autoclave (TEM-D1000M), and then 837 g of an aqueous sodium hydrogen sulfide solution (NaSH concentration 20% by mass) (1.2 mol times the amount of chlorine in the terminally halogenated polyether polymer) was added. At this time, the proportion of the terminally halogenated polyether polymer in the volume of the closed system (reaction vessel) was 25 vol%. No phase transfer catalyst (PTC) was used. After sealing the vessel without gas displacement, the temperature was raised and the displacement reaction was carried out by stirring at 90°C for 7 hours. The internal pressure during the displacement reaction was controlled by venting gas from a pressure regulating valve so that the maximum internal pressure was 0.4 MPa. Subsequently, the salt was removed and neutralization was performed to obtain a colorless, transparent liquid thiol group-containing polyether polymer.

[0093] The obtained thiol group-containing polyether polymer had a thiol group content of 12.6% by mass, a viscosity of 15.5 Pa·s, and a chlorine content of 5500 ppm.

[0094] The conditions and measurement results for Examples 7-9 and Comparative Examples 1-4 described above are summarized in Table 2.

[0095] [Table 2]

Claims

1. A method for producing a thiol group-containing polyether polymer by reacting a terminal halogenated polyether polymer with a hydrogen sulfide metal salt by substitution reaction, wherein the terminal halogenated polyether polymer has a polyether portion represented by the following general formula (1) in its main chain and a structure represented by the following general formula (2) at its end, the hydrogen sulfide metal salt is represented by the following general formula (3), the thiol group-containing polyether polymer has a polyether portion represented by the following general formula (1) and a structural unit represented by the following formula (4) at its end, the substitution reaction is carried out in a closed system, the terminal halogenated polyether polymer is charged into the closed system in an amount of 20% by volume or more of the volume of the closed system, the hydrogen sulfide metal salt is charged into the closed system as an aqueous solution with a concentration of 25% by mass or more, and the substitution reaction is carried out while the gauge pressure in the closed system is 0.1 to 3.0 MPa. R １ [-(R ２ O) ｎ ] ｍ - (1) In formula (1), R １ R is a group with a structure obtained by removing a hydrogen atom from a polyhydric amine or polyhydric alcohol having 10 or fewer carbon atoms. ２ is an alkylene group having 2 to 6 carbon atoms, n is an integer from 1 to 200, and m is an integer from 2 to 8. -CH ２ CH(OH)CH ２ -X (2) In equation (2), X is a halogen atom. M(SH) ｋ (3) In equation (3), M is an alkali metal or alkaline earth metal, and k is an integer between 1 and 2. -CH ２ CH(OH)CH ２ -SH (4)

2. A method for producing a thiol group-containing polyether polymer according to claim 1, wherein hydrogen sulfide gas is not supplied from outside the closed system.

3. A method for producing a thiol group-containing polyether polymer according to claim 1 or 2, comprising the step of performing an addition reaction to form the terminal halogenated polyether polymer by reacting a polyether polyol having a polyether portion represented by the general formula (1) with an epihalohydrin.

4. The method for producing a thiol group-containing polyether polymer according to claim 3, wherein the polyether polyol is polypropylene glycol obtained by adding propylene oxide to glycerin, trimethylolpropane, trimethylolethane, or pentaerythritol.

5. A method for producing a thiol group-containing polyether polymer according to claim 1 or 2, wherein the hydrogen sulfide metal salt is sodium hydrogen sulfide.

6. A method for producing a thiol group-containing polyether polymer according to claim 1 or 2, wherein no phase transfer catalyst is used in the substitution reaction.

7. A method for producing a thiol group-containing polyether polymer according to claim 1 or 2, wherein an aqueous solvent is used in the substitution reaction.

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