JP2016065152A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition based on a thiol-terminated liquid polysulfide polymer free of a crosslinked structure, the composition exhibiting performance comparable to those based on a liquid polysulfide polymer having a crosslinked structure in the skeleton.SOLUTION: A curable composition contains: a thiol-terminated liquid polysulfide polymer represented by the general formula HS-(R-S)-R-SH, where x is an integer from 1 to 5 and has an average value from 1 to 2.5, n is an integer from 1 to 200, and R is a divalent organic group including -OCHO-; a polyfunctional thiol-terminated compound including an ester structure; and an oxidizing agent.SELECTED DRAWING: None

Description

  The present invention relates to a curable composition containing a thiol-terminated liquid polysulfide polymer containing no crosslinked structure, a polyfunctional thiol-terminated compound containing an ester structure, and an oxidizing agent.

  The liquid polysulfide polymer has a thiol group at the terminal and is easily oxidized and cured by an oxidizing agent such as lead dioxide or manganese dioxide. The rubber-like cured product obtained by curing the liquid polysulfide polymer contains sulfur in the main chain of the molecule and does not contain double bonds, making it oil resistant, weather resistant, water tight, and air tight. Because of its excellent characteristics and good adhesion, it is widely used as a sealing material, adhesive and paint. In particular, in multilayer glass applications, it has been used for a long time because of its excellent curability, watertightness and airtightness, which is superior to other base materials such as silicone sealants.

  As commercial products of the liquid polysulfide polymer, various varieties having different molecular weights and cross-linking amounts known as “Thiocol LP” manufactured by Toray Fine Chemical and “ThioplastG” manufactured by AkzoNobel are sold. The cross-linked structure of these commercially available liquid polysulfide polymers is formed by introducing a branched alkylene group such as trichloropropane in an amount determined for each type during polymerization. (See Patent Document 1). In various applications such as sealing materials, adhesives, and paints, in order to satisfy the required performance of physical properties, appropriate types of polymers and compounding agents are selected and physical properties are adjusted.

  Trichloropropane is a substance that is confirmed to be carcinogenic and reproductive toxic, and should be handled with care. For this reason, there has been a demand for a method for controlling the amount of the crosslinked structure of the liquid polysulfide polymer as required without using trichloropropane.

  In addition, when various types of polymers having different molecular weights and cross-linking amounts are produced, polymer loss may occur due to product switching. For this reason, development of the manufacturing method of liquid polysulfide polymer with high production efficiency was desired.

  From these backgrounds, even if a liquid polysulfide polymer not containing a crosslinked structure is used, a curable composition having performance equivalent to that of a liquid polysulfide polymer containing a crosslinked structure in the skeleton or characteristics that could not be achieved with commercial varieties is obtained. If it is possible to produce only liquid polysulfide polymer that does not contain a cross-linked structure, it is expected to improve safety and economic efficiency during production.

US Pat. No. 2,466,963

  An object of the present invention is to provide a curable composition having a performance equivalent to that when a liquid polysulfide polymer having a crosslinked structure in a skeleton is used, using a thiol-terminated liquid polysulfide polymer not containing a crosslinked structure.

The curable composition of the present invention has the general formula HS- (R- _Sx ) _n- R-SH.
(However, x is an integer of 1 to 5, the average value of x is 1 to 2.5, n is an integer of 1 to 200, and R is a divalent organic group containing —OCH ₂ O—)
Is a curable composition containing a thiol-terminated liquid polysulfide polymer, a polyfunctional thiol-terminated compound containing an ester structure, and an oxidizing agent.

  The curable composition of the present invention is characterized by excellent oil resistance, weather resistance, water tightness, and air tightness, similar to a curable composition using a conventional liquid polysulfide polymer.

  The curable composition of the present invention can obtain a cured product having curability and hardness according to the purpose and H-type tensile test properties by selecting the type and amount of the polyfunctional thiol-terminated compound containing an ester structure. it can. In addition, by appropriately selecting the type and amount of the polyfunctional thiol-terminated compound containing an ester structure, it is possible to obtain a cured product having the same performance as a cured product obtained by curing a liquid polysulfide polymer containing a crosslinked structure in the skeleton. it can. A curable composition having appropriate performance can be obtained by using a liquid polysulfide polymer that does not contain a crosslinked structure with good production efficiency.

  The curable composition of the present invention can be used as an adhesive, a sealing material, a potting material, a coating material, a resin modifier, a primer, and the like, particularly for civil engineering / architecture, electric / electronic, vehicle use, and It is optimal as a base composition for aircraft sealants.

  The curable composition of the present invention has characteristics excellent in oil resistance, weather resistance, water tightness, and air tightness, and also has good adhesiveness, and is therefore particularly suitable for a sealing material for double-glazed glass.

  Hereinafter, the present invention will be described in detail.

The thiol-terminated liquid polysulfide polymer used in the curable composition of the present invention is represented by the following general formula: HS— (R—S _x ) _n —R—SH
(However, R is a divalent organic group containing a —O—CH ₂ —O— bond, n is an integer of 1 to 200, x is an integer of 1 to 5, and an average value of x is 1 to 2.5. .)
It is a liquid polymer.

  As for the liquid polysulfide polymer used for the curable composition of this invention, n is an integer of 1-200, Preferably, n is an integer of 1-50.

  In the liquid polysulfide polymer used in the curable composition of the present invention, x is an integer of 1 to 5, preferably x is an integer of 1 to 3, and the average value of x is 1 to 2.5. The average value of x is preferably 1.1 to less than 2. In particular, when the average value of x is less than 2, it is a polymer, a low viscosity, and a low glass transition temperature as compared with a commercially available conventional liquid polysulfide polymer. When cured, the heat resistance becomes high. Tend.

  The liquid polysulfide polymer used in the curable composition of the present invention is liquid at -50 ° C to 100 ° C.

  The number average molecular weight of the liquid polysulfide polymer used in the curable composition of the present invention is preferably 500 to 50,000, more preferably 1,000 to 10,000, still more preferably 1000 to 5, 000.

R of the liquid polysulfide polymer used in the curable composition of the present invention is a divalent organic group containing a —O—CH ₂ —O— bond. R is preferably a divalent alkyl group containing a —O—CH ₂ —O— bond, more preferably a —C ₂ H ₄ —O—CH ₂ —O—C ₂ H ₄ — bond. It is a divalent alkyl group to be contained. More preferably, R has the following chemical structure: —C ₂ H ₄ —O—CH ₂ —O—C ₂ H ₄ —
Is a divalent alkyl group containing 50 mol% or more, and more preferably, the following chemical structure is represented by —C ₂ H ₄ —O—CH ₂ —O—C ₂ H ₄ —.
Is a divalent alkyl group containing 70 mol% or more.

  Since the liquid polysulfide polymer used for the curable composition of the present invention does not contain a branched alkylene group in R, it does not contain a crosslinked structure.

  The liquid polysulfide polymer used in the curable composition of the present invention can be produced by a method of obtaining a liquid polymer via solid polysulfide.

  Moreover, the liquid polysulfide polymer used for the curable composition of this invention can be manufactured with the manufacturing method which does not include formation of the solid polysulfide using a phase transfer catalyst. The liquid polysulfide polymer used in the curable composition of the present invention is preferably a liquid polysulfide polymer produced without the formation of solid polysulfide. For example, the viscosity can be easily controlled by producing by a method that does not include the formation of solid polysulfide using a phase transfer catalyst.

  Preferred phase transfer catalysts are quaternary ammonium salts, phosphonium salts and crown ethers, and more preferred phase transfer catalysts are methyltributylammonium halide, tetrabutylammonium halide, tetraphenylphosphonium halide and 18-crown-6. The most preferred phase transfer catalyst is tetrabutylammonium chloride, tetrabutylammonium bromide, methyltributylammonium chloride, methyltributylammonium bromide. A suitable amount of the phase transfer catalyst is 0.0001 to 0.1 mol, preferably 0.0002 to 0.02 mol, per mol of organic groups R constituting the liquid polysulfide polymer.

The liquid polysulfide polymer used in the present invention can also be obtained by reacting a halogen-terminated sulfur-containing polymer containing an —OCH ₂ O— structure with sodium hydrosulfide.

In the liquid polysulfide polymer used in the present invention, the sulfur content x is preferably prepared by preparing sodium sulfide at the time of charging. Sodium sulfide is preferably prepared by mixing sodium monosulfide (Na ₂ S) and sodium polysulfide (Na ₂ S _x : x is 2 or more). As the supply source of sodium monosulfide and sodium polysulfide, those adjusted by any convenient method such as a combination of sodium hydrosulfide, sodium hydroxide and sulfur can be used.

  The curable composition of the present invention contains a specific thiol-terminated liquid polysulfide polymer, a polyfunctional thiol-terminated compound containing an ester structure, and an oxidizing agent.

  In the present invention, the polyfunctional thiol-terminated compound containing an ester structure includes trimethylolpropane trimercaptopropionate, trimethylolethane trimercaptopropionate, trimethylolpropane trimercaptoacetate, pentaerythritol-tetrakisthioglycolate, penta Examples include erythritol-tetrakis-3-mercaptopropionate and dipentaerythritol hexakis- (3-mercapto) -propionate. These can be used as a crosslinking agent, and two or more kinds may be used. The polyfunctional thiol-terminated compound containing an ester structure is preferably pentaerythritol-tetrakis-3-mercaptopropionate or trimethylolpropane trimercaptopropionate, more preferably pentaerythritol-tetrakis-3-mercaptopropionate.

  As for the addition part number of the polyfunctional thiol terminal compound containing ester structure, it is desirable that it is 0.1-50 weight part with respect to 100 weight part of thiol terminal liquid polysulfide polymer. If the amount is less than 0.1 part by weight, a sufficient crosslinking effect may not be obtained. If the amount exceeds 50 parts by weight, the hardness may be too high. More preferably, the addition part number of the polyfunctional thiol-terminated compound containing an ester structure is 0.1 to 20 parts by weight, more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the thiol-terminated liquid polysulfide polymer. .

  As the polyfunctional thiol-terminated compound containing an ester structure, a crosslinking agent not containing an ester structure can be used at the same time as necessary.

  In the present invention, as the oxidizing agent, substances that have been used as curing agents for conventional liquid polysulfide polymers can be used. Specific examples of these curing agents include inorganic oxidizing agents, organic peroxides, organic oxidizing agents and the like.

  Inorganic oxidizing agents include manganese dioxide, lead dioxide, zinc peroxide, calcium peroxide, iron dioxide, barium peroxide, tellurium dioxide, selenium dioxide, tin dioxide, trilead tetroxide, strontium peroxide, lithium peroxide, etc. Inorganic peroxides, zinc oxide, iron (II) oxide, lead oxide, iron (III) oxide, antimony trioxide, magnesium oxide, cobalt oxide, calcium oxide, copper oxide, barium oxide and other inorganic oxides, chromic acid Examples include sodium, potassium chromate, sodium dichromate, potassium dichromate, sodium perchlorate, sodium perborate, potassium permanganate, sodium percarbonate, and the like. Among these, manganese dioxide and lead dioxide are preferable, and manganese dioxide is particularly preferable.

  Examples of the organic peroxide include hydroperoxide, dialkyl peroxide, peroxy ketal, peroxy ester, peroxy dicarbonate, diacyl peroxide and the like. In particular, cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, and t-butyl peroxybenzoate are particularly preferred organic peroxides because they are excellent in hardness. Two or more kinds of the organic peroxides may be used.

  Examples of the organic oxidizing agent include nitrobenzene, dinitrobenzene, paraquinone dioxime and the like.

  It is preferable that the addition part of an oxidizing agent is 1-50 weight part with respect to 100 weight part of thiol terminal liquid polysulfide polymer. If it is less than 1 part by weight, a sufficient curing rate may not be obtained. If it exceeds 50 parts by weight, it may be cured immediately after mixing and workability may not be obtained. The number of additions of the oxidizing agent is more preferably 1 to 30 parts by weight, still more preferably 1 to 20 parts by weight, even more preferably 5 to 15 parts per 100 parts by weight of the thiol-terminated liquid polysulfide polymer. Parts by weight.

  The curable composition of the present invention can contain a filler, if necessary. Examples of the filler include inorganic fillers such as calcium carbonate, aluminum oxide, aluminum hydroxide, silica, silicate, and sulfate, and carbon black. Carbon black is preferable.

  It is preferable that the addition part number of a filler is 0.1-500 weight part with respect to 100 weight part of thiol terminal liquid polysulfide polymer. If the amount is less than 0.1 parts by weight, sufficient reinforcement and hardening cannot be obtained. If the amount exceeds 500 parts by weight, the viscosity becomes high and workability cannot be obtained. More preferably, the number of added parts of the filler is 1 to 300 parts by weight, even more preferably 10 to 200 parts by weight, and even more preferably 30 to 100 parts by weight with respect to 100 parts by weight of the thiol-terminated liquid polysulfide polymer. 60 parts by weight.

  The curable composition of the present invention preferably contains a plasticizer and a curing accelerator for the purpose of improving economic efficiency, workability during construction of the composition, and physical properties after curing.

Plasticizers include phthalates such as dibutyl phthalate, butyl benzyl phthalate, alkyl phthalate (C ₇ -C ₉ ) benzyl, chlorinated paraffin, dipropylene glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol dibenzoate , Dipropylene glycol monobenzoate, hydrogenated terphenyl, halogen-terminated sulfur-containing polymer, and the like. The plasticizer is preferably a phthalate ester, chlorinated paraffin, dipropylene glycol dibenzoate, a halogen-terminated sulfur-containing polymer.

  The number of added plasticizers is determined by the strength and elongation of the cured product, and further the viscosity design before curing, but is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the thiol-terminated liquid polysulfide polymer. When the added part of the plasticizer exceeds 100 parts by weight, the amount of non-reactive liquid may increase and the hardness may not be maintained. The number of parts added of the plasticizer is more preferably 1 to 50 parts by weight, and still more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the thiol-terminated liquid polysulfide polymer.

  The curable composition of this invention can contain a hardening accelerator as needed. Examples of the curing accelerator include vulcanization accelerators such as aldehyde / ammonia and aldehyde / amine, thiourea, guanidine, thiazole, sulfenamide, thiuram, dithiocarbamate, and xanthate. The curing accelerator is preferably a thiuram vulcanization accelerator or a guanidine vulcanization accelerator. More preferred are tris (dimethylaminomethyl) phenol, diphenylguanidine, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, and hexamethylenetetramine.

  The number of added parts of the curing accelerator is set depending on the curing rate of the curable composition and the use temperature, but is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the thiol-terminated liquid polysulfide polymer. When the addition part of a hardening accelerator exceeds 10 weight part, the remaining accelerator which did not participate in reaction may reduce the performance of hardened | cured material. More preferably, it is 1-5 weight part, More preferably, it is 1-3 weight part.

  The curable composition of the present invention comprises, in addition to the polymer, the crosslinking agent, the oxidizing agent, the filler, the plasticizer, and the curing accelerator, depending on the intended use of the curable composition, an adhesion promoter, an ultraviolet absorber, an oxidizing agent. It may contain an inhibitor, a tackifier, a rubber / elastomer, a fungicide, a corrosion inhibitor, a pigment, a masking agent or an additive having a different action.

  Examples of the adhesion promoter include a silane coupling agent containing a hydrolyzable silyl group and a reactive organic functional group. Specifically, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4 epoxy cyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyl Triethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane, N-2 (amino Ethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl- Examples include 3-aminopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, and bis (triethoxysilylpropyl) tetrasulfide. A terminal trimethoxysilane-modified polysulfide polymer synthesized by reacting the polysulfide polymer “thiocol LP-3” with 3-gridoxypropyltrimethoxysilane can also be used as a silane coupling agent. Two or more of these silane coupling agents may be used.

  Examples of the ultraviolet absorber include benzophenone series, benzotriazole series, phenyl salicylate series, triazine series, nickel salt and nickel complex series. Specifically, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- [2-hydroxy-3 (3,4,5,6-tetra-hydrophthalimidomethyl) -5-methylphenyl] ben Sotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-4-octylphenyl) benzotriazole, 2- (2-hydroxy- 3,5-t-butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-t-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-5-t-octylphenyl) benzo Triazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, nickel dibutyldithiocarba Over DOO, [2,2'-thiobis (4-t-octyl phenolate)] - 2-ethylhexylamine - such as nickel and the like.

  Examples of the antioxidant include amine-based antioxidants, phenol-based antioxidants, phosphite-based antioxidants, and thioether-based antioxidants. Specifically, 1,3,5-tris [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] -1,3,5-triazine-2,4,6 ( 1H, 3H, 5H) -trione, 1,1,3-tris (5-tert-butyl-4-hydroxy-2-methylphenyl) butane, 1,1-bis (4-hydroxy-2-methyl-5- tert-Butylphenyl) butane, 2,2-bis [[[3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] oxy] methyl] propane-1,3-diol 1,3- Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis (3-tert-butyl-4-hydroxy-5-methylbenzenepropanoic acid) ethylene bis (oxyethylene ), 4,4 ′, 4 ″-[(2,4,6-trimethylbenzene-1,3,5-triyl) tris (methylene)] tris (2,6-di-tert-butylphenol) It is done.

Examples of tackifiers include phenol resins, coumarone / indene resins, coumarone resins, naphthenic oils, rosins, rosin esters, hydrogenated rosin derivatives, terpene resins, modified terpene resins, terpenes / phenolic resins, hydrogenated terpene resins, α- pinene resins, alkylphenol-acetylene resin, alkylphenol-formaldehyde resins, styrene resins, C ₆ petroleum resins, C ₉ petroleum resins, alicyclic petroleum resins, C 6 _/ C ₉ copolymer petroleum resin, Examples include xylene-formaldehyde resins.

  As rubber and elastomer, natural rubber, polybutadiene rubber, acrylic rubber, polyisoprene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, olefin elastomer, styrene elastomer, vinyl chloride elastomer, polyester elastomer, polyamide Based elastomer, polyurethane based elastomer, polysiloxane based elastomer and the like.

  The curable composition of the present invention is cured under an atmosphere of 23 ° C. and 50% RH, and after mixing and mixing the main agent and curing agent, the hardness after 2 hours is measured with a type A durometer described in K6253. When performed, the hardness (Shore A) is preferably 15 or more, more preferably 20 or more, and even more preferably 21 to 50.

Further, the maximum point stress T _max when the main agent and the curing agent are thoroughly kneaded by hand kneading and subjected to a tensile test at a speed of 50 mm / min in an atmosphere of 23 ° C. and 50% RH after being cured at 23 ° C. and 50% RH for 7 days. (N / cm ² ) is preferably 90 or more, more preferably 100 or more, and even more preferably 105 to 200.

  Furthermore, the curable composition of the present invention can be used for an adhesive, a sealing material, a potting material, a coating material, a resin modifying material, a primer, and the like, and in particular, used for a sealing material for multilayer glass. it can.

  The invention is illustrated in more detail by the following examples.

Synthesis example 1
Using a 2 L separable flask, 1770 g sodium polysulfide aqueous solution (2.20 mol / L), 5.6 g tetrabutylammonium bromide 50 wt% aqueous solution, 48 g 42% sodium hydrosulfide aqueous solution, 604 g bis (2- Chloroethyl) formal was reacted to obtain a light yellow, transparent, thiol-terminated liquid polysulfide polymer that did not pass through solid polysulfide and did not contain crosslinks. The obtained polymer had a viscosity of 11.5 Pa · s and an SH content of 2.6%.

Example 1
As the main agent, the polymer of Synthesis Example 1 which is a thiol-terminated liquid polysulfide polymer containing no cross-linked structure, the polyfunctional thiol-terminated compound containing an ester structure, pentaerythritol-tetrakis-3-mercaptopropionate, butyl benzyl phthalate, precipitation Calcium carbonate, heavy calcium carbonate, and 3-glycidoxypropyltrimethoxysilane were mixed using a mixer. The mixing ratio is shown below.

Main ingredient composition
-99 parts by weight of the liquid polysulfide polymer of Synthesis Example 1-1 part by weight of pentaerythritol-tetrakis-3-mercaptopropionate (Maruzen Oil Chemical Co., Ltd.)-39 parts by weight of butylbenzyl phthalate (manufactured by Daihachi Chemical)-Precipitated calcium carbonate (Shiraishi calcium white glaze CC) 65 parts by weight Heavy calcium carbonate (Shiraishi calcium Whiten SSB red) 90 parts by weight 3-glycidoxypropyltrimethoxysilane
(Toray Dow Corning SH-6040) 1.5 parts by weight As a curing agent, a three-roll mill comprising manganese dioxide, butylbenzyl phthalate, phthalic acid plasticizer, tetramethylthiuram disulfide, heavy calcium carbonate, SFR carbon Were kneaded using.

Composition of curing agent • Manganese dioxide (TypeFA manufactured by Honeywell) 10 parts by weight • Butyl benzyl phthalate (manufactured by Daihachi Chemical) 2.5 parts by weight • Phthalic acid plasticizer (Santisizer 278 manufactured by Ferro) 10.5 parts by weight Tetramethylthiuram disulfide (Noxeller TT, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.) 0.5 parts by weight, heavy calcium carbonate (NCC # 410, manufactured by Nitto Flour Chemical Co., Ltd.) 5 parts by weight, 0.5 parts by weight of SRF carbon The main agent and the curing agent were well kneaded by hand to prepare a 10 mm thick test piece with a curable composition comprising the mixture. This test piece was cured under an atmosphere of 23 ° C. and 50% RH, mixed with the main agent and a curing agent, and after 2 hours, 6 hours, 1 day, and 7 days, the type described in JIS K6253 (2012) The hardness was measured with an A durometer. The measurement conditions were the method described in JIS K6253 (2012).

Further, the main agent and the curing agent were well kneaded by hand, and three H-type specimens according to JIS A1439 (2010) were prepared from the curable composition comprising the mixture. The adherend is made of glass, the curing condition is 7 days at 23 ° C. and 50% RH, and a tensile test is performed at a rate of 50 mm / min in an atmosphere of 23 ° C. and 50% RH using Tensilon RTA-500 manufactured by Orientec. It was. For each of the three test pieces, the stress M ₁₀ (N / cm ² ) at 10% elongation, the maximum point stress T _max (N / cm ² ), and the elongation at break (%) were determined, and the average values were expressed. It is shown in 1.

Comparative Example 1
In place of the thiol-terminated liquid polymer (99 parts by weight) and pentaerythritol-tetrakis-3-mercaptopropionate (1 part by weight) of Example 1 without the crosslinking of Synthesis Example 1, the crosslinking of Synthesis Example 1 is not included. Using the thiol-terminated liquid polymer (100 parts by weight), the hardness and H-type tensile physical properties of the curable composition were determined in the same manner as in Example 1.

Reference example 1
A commercial product having a cross-linked structure in the skeleton instead of the thiol-terminated liquid polymer (99 parts by weight) and pentaerythritol-tetrakis-3-mercaptopropionate (1 part by weight) not including the cross-linking of Synthesis Example 1 of Example 1 Using the liquid polysulfide polymer “thiocol LP-23 (manufactured by Toray Fine Chemical)” (100 parts by weight), the hardness and H-type tensile properties of the curable composition were determined in the same manner as in Example 1.

The curable composition using the thiol-terminated liquid polysulfide polymer that does not contain a crosslinked structure as in Comparative Example 1 was so soft that it could not be measured even though it was cured. Moreover, since it is a hardened | cured material which deform | transforms when force is applied, an H-type test piece could not be produced and an H-type tensile test could not be carried out. As in Example 1 of the present invention, by adding a polyfunctional thiol-terminated compound to a thiol-terminated liquid polysulfide polymer that does not contain a crosslinked structure, the hardness and H-type tensile properties of the curable composition are greatly improved. 2 hours hardness (Shore A) is 20 or more, maximum point stress T _max (N / cm ² ) in H-type tensile test is 100 or more, and it is a standard used for the sealing material for multilayer glass shown in Reference Example 1. The same physical properties as those of other curable compositions were exhibited.

Claims (5)

General formula HS- (R- _Sx ) _n- R-SH
(However, x is an integer of 1 to 5, the average value of x is 1 to 2.5, n is an integer of 1 to 200, and R is a divalent organic group containing —OCH ₂ O—)
A curable composition comprising a thiol-terminated liquid polysulfide polymer represented by the formula, a polyfunctional thiol-terminated compound containing an ester structure and an oxidizing agent. The curable composition according to claim 1, wherein the polyfunctional thiol-terminated compound containing an ester structure is pentaerythritol-tetrakis-3-mercaptopropionate. The curable composition according to claim 1 or 2, wherein the hardness after 2 hours (Shore A) at 23 ° C and 50% RH is 20 or more. The curable composition according to any one of claims 1 to 3, wherein the maximum point stress T _max (N / cm ² ) in the H-type tensile test after curing at 23 ° C and 50% RH for 7 days is 100 or more. It is a curable composition for sealing materials for multilayer glass, The curable composition in any one of Claims 1-4.