JP6976523B2 - Curable composition - Google Patents

Description

The present invention relates to a curable composition containing a liquid polyether polymer having a terminal thiol group, zinc aluminosilicate, and a sulfur-based vulcanizing agent, which is suitably used for a sealing material, an adhesive, a coating material and the like.

A liquid polymer having two or more thiol groups in one molecule, for example, a polysulfide polymer, is cured by an oxidizing agent and exhibits rubber elasticity, and is used as a sealing material for civil engineering, construction, and the like. Conventionally, lead dioxide and manganese dioxide have been used as a curing agent for this polysulfide rubber. Lead dioxide and manganese dioxide are dark brown powders. Polysulfide rubber cured with these curing agents can be obtained as a gray-colored cured product by blending a large amount of expensive titanium dioxide, but cannot be completely white.

Examples of the inorganic curing agent for obtaining a white polysulfide rubber include calcium oxide, barium peroxide, zinc peroxide and sodium perboroate. However, calcium oxide, barium peroxide, zinc peroxide and sodium perboroate generally have a slow curing rate, so a large amount of water must be used as a curing accelerator aid, and the water tends to evaporate during kneading and storage. It is difficult to control to obtain a constant curing rate. Further, when sodium perborate is used as a curing agent, a phenomenon of foaming at a high temperature is observed, which is a problem. Cumene hydroperoxide, benzoyl peroxide and the like, which are mentioned as organic curing agents, require a very long time to be completely cured at room temperature with respect to the liquid polysulfide polymer. Further, in recent years, the above-listed inorganic curing agents and organic curing agents have become difficult to use due to stricter legal regulations due to their influence on the human body and the environment.

Against this background, a paste-like curing agent composition composed of zinc aluminosilicate or zinc silicate and a curing type composition using the same are disclosed (see Patent Document 1).

The cured polysulfide using zinc amminosilicate softens in one week when exposed to 90 ° C. curing, and has poor heat resistance. Further, polysulfide cured with zinc silicate is only further 80 ° C. to cure 1 week H type sample after initial curing, reduced to 0.90kg / cm ² 50% modulus value from 1.53 kg / cm ² (The retention rate of the 50% modulus value was 59%). The cured polysulfide using zinc silicate did not retain satisfactory heat resistance for applications exposed to high temperatures.

From the above, there has been a demand for a white curable composition using commercially available zinc aluminosilicate as a curing agent and having good heat resistance of the cured product after curing.

Japanese Unexamined Patent Publication No. 47-34448

An object of the present invention is to use zinc aluminosilicate as a white curing agent for a liquid polymer having a terminal thiol group, and to provide a cured composition having good heat resistance after curing.

The present invention is a curable composition containing a liquid polyether polymer having a thiol group at the terminal, zinc aluminosilicate, and a sulfur-based sulfide agent, wherein the liquid polyether polymer having a thiol group at the terminal is 1. It contains 3 or more thiol groups in the molecule, and further
(A) In the main chain,
(A) R ₁ [-(R ₂ O) _n ] _m-
(However, R ₁ is a residue obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 12 or less carbon atoms, R ₂ is an alkylene group having 2 to 4 carbon atoms, and n is 6 to 200. Is an integer of, and m is an integer of 3 to 8.)
And the polyoxyalkylene part represented by
(A) -CH ₂ CH (OH) CH _2- S _x-
(However, x is an integer of 1 to 5)
Contains structural units represented by, and at the end,
(C) -CH ₂ CH (OH) CH _2- SH
It is a curable composition which is a liquid polyether polymer having a structural unit represented by.

The curing agent used in the curable composition of the present invention is zinc aluminosilicate, which does not contain highly toxic heavy metals, and therefore has less adverse effect on the human body than conventional curing agents such as lead dioxide and manganese dioxide. Low toxicity and excellent safety.

The curable composition of the present invention has little decrease in hardness and tensile stress (modulus) when exposed to high temperature.

The curable composition of the present invention is a white or light-colored curable composition.

The curable composition of the present invention can be used as a sealing material, an adhesive and a coating material for civil engineering / building, double glazing, electric / electronic, and vehicles.

It is a drawing substitute photograph of the cured product of Example 5 using zinc alminosilicate (right) and the cured product obtained by blending 5 parts by weight of manganese dioxide with the main agent of Example 5 and curing it (left).

Hereinafter, the present invention will be described in detail.

The liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention is contained in the main chain.
(A) R ₁ [-(R ₂ O) _n ] _m-
(However, R ₁ is a residue obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 12 or less carbon atoms, R ₂ is an alkylene group having 2 to 4 carbon atoms, and n is 6 to 200. Is an integer of, and m is an integer of 3 to 8.)
And the polyoxyalkylene part represented by
(B) -CH ₂ CH (OH) CH _2- Sx-
(However, x is an integer of 1 to 5)
Contains structural units represented by, and at the end,
(C) -CH ₂ CH (OH) CH _2- SH
It has a structural unit represented by.

In the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention, R ₁ is preferably glycerin, trimethylolpropane, hexanetriol, triethanolamine, diglycerin, pentaerythritol, ethylenediamine, It is a residue obtained by removing a hydrogen atom from sucrose or the like, and more preferably a residue obtained by removing a hydrogen atom from glycerin.
In the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention, R ₂ is preferably an ethylene group, a propylene group, a trimethylene group, or a tetramethylene group, and more preferably a propylene group. Is.

In the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention, n is preferably 10 to 150, more preferably 20 to 80.

In the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention, m is preferably 3 to 4, more preferably 3.

In the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention, x is preferably 1 to 3 and more preferably 1 to 2.

The liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention contains three or more thiol groups in one molecule. The liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention preferably contains 3 to 6 thiol groups in one molecule.

The thiol group content of the liquid polyether polymer having a thiol group at the terminal used in the curable composition of the present invention is preferably 2.0% by weight or less, more preferably 0.5 to 1.8. % By weight.

The weight average molecular weight of the polyether polymer having a thiol group at the terminal used in the curable composition of the present invention is preferably 1,000 to 100,000, more preferably 5,000 to 50,000. Yes, and even more preferably 8,000 to 20,000.

Such a liquid polyether polymer having a thiol group at the terminal is produced by a method of reacting a halogen-terminated prepolymer obtained by adding epihalohydrin to a polyoxyalkylene glycol with an alkali hydrosulfide and / or an alkali polysulfide. Can be done.

The curing agent used in the curable composition of the present invention is zinc aluminosilicate, which is a composite of _{silica (SiO 2} ), zinc oxide (ZnO), and aluminum oxide (Al ₂ O _3). Since zinc alminosilicate does not contain highly toxic heavy metals, it has less adverse effects on the human body than conventional curing agents such as lead dioxide and manganese dioxide, and is low in toxicity and excellent in safety.

Zinc aluminosilicate used in the present invention can be represented as a composite of _{silica (SiO 2} ), zinc oxide (ZnO), and aluminum oxide (Al ₂ O _3). The composition ratio is preferably SiO ₂ : 5 to 80 mol%, ZnO: 5 to 65 mol%, Al ₂ O ₃ : 1 to 60 mol%, and more preferably SiO ₂ : 25 to 75 mol%. , ZnO: 15 to 60 mol%, Al ₂ O _3: 1~45 are mole%.

The zinc aluminosilicate used in the present invention can also be represented by, for example, the following formula (1).
aSiO ₂ , bZnO, cAl ₂ O ₃ , dH ₂ O (1)
When expressed by the above formula, d is 0 or more, a is 1 or more, b is 1 or more, and c is 1 or more.

The nitrogen adsorption specific surface area of zinc alminosilicate, the so-called BET specific surface area, is generally 50 to 800 m ² / g. The zinc aluminosilicate used in the present invention has a BET specific surface area of preferably 100 to 600 m ² / g, and ^{particularly preferably 200 to 400 m 2} / g. If the BET specific surface area is too small, the curability of the thiol group-containing polymer may not be sufficiently exhibited, and conversely, if the BET specific surface area is too large, the dispersibility may be deteriorated.

The zinc aluminosilicate used in the present invention can be either crystalline or amorphous.

As the zinc aluminosilicate used in the present invention, those sold for deodorizing, deodorizing, antibacterial agents and the like can be used. For example, Mizukanite HP manufactured by Mizusawa Chemical Industry Co., Ltd. (SiO ₂ : 60 mol%, ZnO: 33 mol%, Al ₂ O ₃ : 7 mol%, BET specific surface area 200 to 400 m ² / g in the above-mentioned three-component composition ratio. ) And Lionite SF of Lion Specialty Chemical Co., Ltd. (SiO ₂ : 60 mol%, ZnO: 33 mol%, Al ₂ O ₃ : 7 mol%, BET specific surface area 200-400 m ^{2 in the above-mentioned three-component composition ratio} / G) and the like.

A sulfur-based vulcanizing agent is added to the cured composition of the present invention for the purpose of imparting rubber elasticity and strength to the cured product. The sulfur-based vulcanizer is an inorganic elemental sulfur or an organic sulfur donor capable of releasing active sulfur. When a sulfur-based vulcanizing agent is added to a curable composition containing a thiol group-containing liquid polymer and zinc aluminosilicate, the cohesive force of resin cross-linking is enhanced and the heat resistance is improved.

The sulfur-based vulcanizer used in the curable composition of the present invention is an organic sulfur donor capable of releasing elemental sulfur and active sulfur. Examples of elemental sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, and surface-treated sulfur, but those having a small particle size and easily being dispersed in a plasticizer are preferable. Examples of the organic sulfur donor include sulfur-containing organic compounds such as dithiodimorpholin, dithiodicaprolactam, and alkylphenol disulfide, and thiuram-based sulfide accelerators such as tetramethylthium disulfide and dipentamethylene thiuram tetrasulfide, 2-. In addition to thiazole-based vulfurization accelerators such as (4'-morpholinodithio) benzothiazole and polysulfide-type silane coupling agents such as bis (3-triethoxysilylpropyl) tetrasulfide, high-molecular-weight polysulfides having polysulfide bonds are used. Can be used. Examples of the polymer polysulfide include the trade name "Vulcar" series manufactured by Toyo Chemical Co., Ltd., which is solid at room temperature, the terminal thiol-modified polysulfide polymer described in Patent No. 3689856, or the terminal thiol-modified polysulfide polymer described in Patent 3433997. Examples thereof include block copolymers containing polysulfide. As these polysulfide polymers, the number of sulfur bonds is preferably more than 2 and 6 or less on average, and 3 to 5 on average is more preferable because the balance between vulcanization performance and storage stability is good. Further, for applications requiring curing at room temperature, it is more preferable to use a polymer polysulfide that is liquid at room temperature in order to improve dispersibility in the curable composition.

The sulfur-based vulcanizing agent used in the curable composition of the present invention is preferably a simple sulfur, a thiuram-based vulcanization accelerator, a terminal thiol-modified polysulfide polymer, and more preferably simple sulfur.

The content of the sulfur-based vulcanizing agent is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the liquid polyether polymer having a thiol group at the terminal. If it exceeds 10 parts by weight, the change in physical properties after heat curing becomes large and the coloring becomes remarkable, which is not preferable. The content of the sulfur-based vulcanizing agent is more preferably 5 parts by weight or less, still more preferably 2 parts by weight or less, based on 100 parts by weight of the liquid polyether polymer having a thiol group at the terminal.

The curable composition of the present invention preferably contains an antioxidant. As the antioxidant, a phenol-based, amine-based, phosphite-based, or thioether-based antioxidant can be used. Specifically, as a phenolic antioxidant, 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, octadecyl 3- (3,5-tert-butyl-4-hydroxyphenyl) propionate, 2,2-bis [[[3- (3,5-di) -Tart-butyl-4-hydroxyphenyl) propionyl] oxy] methyl] propane-1,3-diol 1,3-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,9-bis [2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] Undecane, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxyphenylmethyl) -2,4,6-trimethylbenzene and the like can be mentioned. Examples of amine-based antioxidants include phenyl-1-naphthylamine, di (4-octyldiphenyl) amine, 4,4'-(α, α-dimethylbenzyl) diphenylamine, and N, N'-di-2-naphthyl-p. -Phenylylenediamine, N-phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine and the like can be mentioned. Phenyl antioxidants include 3,9-bis- (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane, 3,9-bis (2,). 6-Di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5,5] undecane, 2,2'-methylenebis (4,6-di-tert) -Butylphenyl) 2-ethylhexylphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (nonylphenyl) phosphite, tetra-C12-15-alkyl (propane-2,2-diylbis) 4,1-Phenylene)) bis (phosphite), 2-ethylhexyldiphenylphosphite, isodecyldiphenylphosphite, triisodecylphosphite, triphenylphosphite and the like. As thioether-based antioxidants, 2,2-bis [[3- (dodecylthio) -1-oxopropoxy] methyl] propane-1,3-diylbis [3- (dodecylthio) propionate], di (tridecylic) 3 , 3'-thiodipropionate, etc. Two or more kinds of the above-mentioned antioxidants may be used.

As the antioxidant preferably used in the present invention, a phenolic antioxidant having good compatibility with a liquid polymer having a thiol group at the terminal is particularly preferable.

The amount of the antioxidant added is preferably 0.1 to 10 parts by weight, more preferably 5 parts by weight or less, based on 100 parts by weight of the liquid polyether polymer having a thiol group at the terminal.

The curable composition of the present invention is a mixture of a liquid polyether polymer having a thiol group at the terminal, a filler, a main agent containing a plasticizer as a main component, and a curing agent paste containing zinc aluminosilicate and a plasticizer as main components. It is suitably used as a two-component curable composition composed of. The sulfur-based vulcanizing agent required to improve the heat resistance after curing may be blended in either the main agent or the curing agent paste, but the sulfur-based vulcanizing agent is added to ensure the storage viscosity stability of the main agent. It is preferable to add the sulfurizing agent to the curing agent paste side. Further, the main agent and the curing agent paste include an organic acid, a vulcanization accelerator, a curing accelerator such as an organic metal catalyst, an adhesion accelerator, a polyfunctional cross-linking agent, an ultraviolet absorber, and a tackifier, depending on the intended use. , Drying oils, fungicides, corrosion inhibitors, pigments, masking agents or additives with different actions may each be contained.

Examples of the plasticizer that can be used in the curable composition of the present invention include phthalate-based, adipate-based, benzoate-based, phosphate-based, citric acid ester, chlorinated paraffin, and hydrocarbon-based plasticizer. Specifically, dimethylphthalate, dibutylphthalate, dioctylphthalate, diisononylphthalate, butylbenzylphthalate, dibenzylphthalate, hexanolbenzylphthalate, alkylbenzylphthalate, dibutyladipate, bis (butyldiglycol) adipate, dibutyl maleate, Dipropylene Glycol Dibenzoate, Diethylene Glycol Dibenzoate, Triethylene Glycol Dibenzoate, Dipropylene Glycol Monobenzoate, Triethyl Phthalate, Tri-n-butyl Phthalate, Tricresyl Phthalate, Trixylenyl Phthalate, Tributyl Acetylcitrate, Hydrocarbon-based Examples include plasticizers.

Fillers include inorganic fillers such as calcium carbonate, magnesium carbonate, clay, talc, mica, silicic acid, silicate, sulfate, aluminum oxide, aluminum hydroxide, magnesium hydroxide, zeolite, and pearlite, and carbon black. And so on. Also, lightweight polymer fillers such as polyamide and polyethylene, thermoplastic balloons (thermoexpandable microcapsules) such as silica, acrylonitrile, methacryllonitrile and vinylidene chloride, thermosetting balloons such as phenol and epoxy, silas and fly ash. Examples include hollow fillers such as inorganic balloons such as glass and alumina. The preferred filler may be at least one selected from carbon black, calcium carbonate, silica and microballoons. Two or more kinds of fillers may be used, and any of the fillers may be prepared by treating the surface with a fatty acid, a resin acid, a surfactant, a silane coupling agent, paraffin or the like.

The calcium carbonate is preferably heavy calcium carbonate or colloidal calcium carbonate. In general, heavy calcium carbonate is calcium carbonate obtained by mechanically pulverizing and classifying rough limestone to obtain a desired particle size. For colloidal calcium carbonate, rough limestone is co-fired with coke or the like to once produce calcium oxide (quick lime), which is then reacted with water to form calcium hydroxide (slaked lime), which is then reacted with the carbon dioxide gas generated during firing. Calcium carbonate obtained with a desired particle size and particle shape.

The present invention will be described in more detail with reference to the following examples. Unless otherwise specified, the "parts" in the text below are "weight parts" based on weight.

Details of the test method (1) Measurement of thiol content The sample was dissolved in a mixed solution of toluene and pyridine, an aqueous potassium iodide solution was added, and then titration was performed using an iodine standard solution.

(2) GPC analysis: Measurement of number average molecular weight (Mn) and weight average molecular weight (Mw) The column used was TSKgelG3000HXL, TSKgelG2000HXL, and TSKgelG1000HXL connected in series, and the detector was MODEL504R manufactured by GL Science Co., Ltd. RI Detector was used. The sample was dissolved in THF to prepare a 1% THF solution, which was measured at a column temperature of 40 ° C. using THF at a flow rate of 1.0 ml / min as a mobile phase. The molecular weight was calculated using PEG as a standard and using the GPC data processing software SIC480II data station manufactured by Shoko Scientific Co., Ltd.

(3) Preparation of test piece for hardness measurement A cured composition mixed by hand kneading with a spatula was poured into a mold having a thickness of 30 mm × 50 mm × 10 mm and left in an atmosphere of 23 ° C. and 50% RH for 7 days. (Initial curing). The mold was removed to obtain a cured product having a thickness of 30 mm × 50 mm × 10 mm.

(4) Hardness measurement The hardness measurement test piece was measured at three points with a Type E durometer (GSD-721K manufactured by Teclock Co., Ltd.) described in JIS K6253-3, and the average value was calculated.

(5) Heat resistance evaluation (hardness)
The test piece for hardness measurement after the initial curing was left in a constant temperature bath at 90 ° C. for 1 month, and then returned to room temperature to measure the hardness. Further, the hardness was measured after additional curing at 90 ° C. for 1 month. As an index for heat resistance evaluation, a percentage (hereinafter referred to as hardness retention rate (%)) obtained by dividing the hardness after curing at 90 ° C by the hardness after initial curing is calculated, and a hardness retention rate of 70% or more is ○ (passed). , Less than 70% was regarded as x (failure), and a pass / fail judgment was made.

(7) H-type tensile test Tensile of three H-type specimens was carried out according to the 5.20 tensile adhesiveness test of JIS A1439-2016, and the average value _{of stress (50% modulus, M 50) at the time of 50% elongation was obtained.} I asked.

(8) Heat resistance evaluation (modulus)
The three H-type specimens after the initial curing were left in a constant temperature bath at 90 ° C. for 2 weeks, returned to room temperature, and subjected to a tensile test to obtain the average value of M50. As an index for heat resistance evaluation, a percentage (hereinafter referred to as M50 retention rate (%)) obtained by dividing M50 after curing at 90 ° C for 2 weeks by M50 after initial curing is calculated, and M50 retention rate of 70% or more is ○. A pass / fail judgment was made with (pass) and less than 70% as x (fail).

Synthesis example 1
500 g of trifunctional polypropylene glycol (PREMINOL S3011, OH value 17.2 manufactured by Asahi Glass Co., Ltd.) obtained by adding propylene oxide to glycerin and 0.25 g of stannic chloride pentahydrate are charged in a 2 liter reaction vessel. The temperature was raised to 50 ° C., 16.3 g of epichlorohydrin was added dropwise over 1 hour, and after the addition, the mixture was stirred at 80 ° C. for 3 hours. To the obtained halogen-terminated polyether polymer, 500 g of N, N-dimethylformamide was added and mixed, 22.6 g of an aqueous sodium sulfide aqueous solution (concentration 48.1%) was added, nitrogen substitution was performed, and the mixture was stirred at 80 ° C. for 2 hours. did. Then, 1.0 g of citric acid was added for neutralization, and the precipitated salt and N, N-dimethylformamide were removed by filtration and vacuum distillation to obtain a pale yellow transparent liquid polymer. The thiol content of the obtained polymer was 0.78% by weight, the viscosity was 16.3 Pa · s (25 ° C.), the number average molecular weight was Mn = 7,100, and the weight average molecular weight was Mw = 15,700.

Synthesis example 2
500 g of trifunctional polypropylene glycol (EXCENOL 5030 manufactured by Asahi Glass Co., Ltd., OH value 33.0) obtained by adding propylene oxide to glycerin and 0.25 g of ferric chloride pentahydrate are charged in a 2 liter reaction vessel. The temperature was raised to 50 ° C., 35.1 g of epichlorohydrin was added dropwise over 1 hour, and after the addition, the mixture was stirred at 80 ° C. for 3 hours. To the obtained halogen-terminated polyether polymer, 500 g of N, N-dimethylformamide was added and mixed, 43.4 g of an aqueous sodium sulfide aqueous solution (concentration 48.1%) was added, nitrogen substitution was performed, and the mixture was stirred at 80 ° C. for 2 hours. did. Then, 2.0 g of citric acid was added for neutralization, and the precipitated salt and N, N-dimethylformamide were removed by filtration and vacuum distillation to obtain a pale yellow transparent liquid polymer. The thiol content of the obtained polymer was 1.69% by weight, the viscosity was 5.1 Pa · s (25 ° C.), the number average molecular weight was Mn = 4,000, and the weight average molecular weight was Mw = 12,500.

Synthesis example 3
500 g of bifunctional polypropylene glycol (EXCENOL 3020 manufactured by Asahi Glass Co., Ltd., OH value 36.1) obtained by adding propylene oxide to glycerin and 0.25 g of ferric chloride pentahydrate are charged in a 2 liter reaction vessel. The temperature was raised to 50 ° C., 31.3 g of epichlorohydrin was added dropwise over 1 hour, and after the addition, the mixture was stirred at 80 ° C. for 3 hours. To the obtained halogen-terminated polyether polymer, 500 g of N, N-dimethylformamide was added and mixed, 48.7 g of an aqueous sodium sulfide aqueous solution (concentration 48.1%) was added, nitrogen substitution was performed, and then the mixture was stirred at 80 ° C. for 2 hours. did. Then, 2.3 g of citric acid was added for neutralization, and the precipitated salt and N, N-dimethylformamide were removed by filtration and vacuum distillation to obtain a pale yellow transparent liquid polymer. The obtained polymer had a thiol content of 1.77% by weight, a viscosity of 2.3 Pa · s (25 ° C.), a number average molecular weight Mn = 2,800, and a weight average molecular weight Mw = 6,900.

Synthesis example 4
A 1-liter reaction vessel containing 125 g of toluene, 15.0 g of triethylamine, and 67.3 g of n-butyl acrylate in a polysulfide polymer (manufactured by Toray Fine Chemicals Co., Ltd., product name: LP-23, thiol group content 2.84% by weight). And stirred at 80 ° C. for 8 hours. After the reaction, the thiol content of the polymer was 0.03% by weight or less, and a polysulfide polymer having a butyl ester terminal was obtained. Subsequently, when 202 g of powdered sulfur was charged and stirred at 80 ° C. for 3 hours, the solid sulfur in the reaction solution disappeared, and the reaction solution became transparent in red. Then, toluene and triethylamine were removed by vacuum distillation to obtain an odorless, dark red transparent liquid polymer. This liquid polymer is a liquid polysulfide polymer having a butyl ester terminal and a number of repeated sulfur bonds of 4 in the main chain skeleton. The viscosity of the obtained polymer was 27.9 Pa · s (25 ° C.), and no sulfur precipitation or thickening occurred even after storage at room temperature for 1 month.

Example 1
For 100 parts of the terminal thiol-containing polyoxypropylene polymer obtained in Synthesis Example 1, a phenolic antioxidant (manufactured by ADEKA Co., Ltd., product name: AO-80, chemical name: 3,9-bis [2-- With [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane] Zinc ammonium silicate and powdered sulfur as a sulfur-based vulcanizing agent were blended in the number of parts shown in Table 1, and the heat resistance was evaluated with the obtained cured product. The results are shown in Table 1.

Example 2
A cured product was prepared with the same composition except that the sulfur-based vulcanizing agent of Example 1 was changed to the combined use of powdered sulfur and the polymer polysulfide of Synthesis Example 4, and the heat resistance was evaluated. The results are shown in Table 1.

Example 3
The terminal thiol-containing polymer of Example 1 was used as the polyoxypropylene polymer of Synthesis Example 2, and a cured product was prepared with the same composition except that the amount of zinc aluminosilicate was increased, and the heat resistance was evaluated. The results are shown in Table 1.

Example 4
The terminal thiol-containing polymer of Example 1 was used as a mixed system of the polyoxypropylene polymer of Synthesis Example 2 and the polyoxypropylene polymer of Synthesis Example 3, and the same composition was used except that the amount of zinc aluminosilicate as a curing agent was increased. A cured product was prepared and heat resistance was evaluated. The results are shown in Table 1.

Comparative Example 1
The terminal thiol-containing polymer of Example 1 was a polysulfide polymer (manufactured by Toray Fine Chemical Co., Ltd., product name: LP-32, thiol content 1.74% by weight, weight average molecular weight 4,000), and a curing agent, zinc aluminosilicate, was used. A cured product was prepared with the same composition except that the amount was increased, and the heat resistance was evaluated. The results are shown in Table 1.

Comparative Example 2
A cured product was prepared with the same composition as in Example 1 except that the sulfur-based vulcanizing agent (powdered sulfur) was not used, and the heat resistance was evaluated. The results are shown in Table 1.

Comparative Example 3
The terminal thiol-containing polymer of Example 1 was used as the polyoxypropylene polymer of Synthesis Example 3, and a cured product was prepared with the same composition except that the amount of zinc aluminosilicate as a curing agent was increased, and the heat resistance was evaluated. The results are shown in Table 1.

A cured product of a polysulfide polymer (product name: Thiocol LP-32), which is widely used as a thiol group-containing polymer for civil engineering and building sealants, cured with zinc aluminosilicate is a sulfur-based vulcanizer (powdered sulfur) under high temperature. Even if a phenolic antioxidant that suppresses radical oxidation and the like was used in combination, sufficient heat resistance could not be maintained after curing at 90 ° C. for 2 months (Comparative Example 1). On the other hand, when an antioxidant and a sulfur-based vulcanizing agent are used in combination and replaced with the trifunctional polyoxypropylene polymer obtained in Synthesis Examples 1 and 2 as a thiol group-containing polymer, after curing at 90 ° C. for 2 months. It was found that the heat resistance of the above can be significantly improved (Examples 1 to 3). It can be seen that the heat resistance can be maintained when the compounding ratio of the bifunctional polyoxypropylene polymer and the trifunctional polyoxypropylene polymer is 60:40 (Example 4).

Further, even if a trifunctional polyoxypropylene polymer is blended instead of the polysulfide polymer (product name: Thiocol LP-32), the heat resistance of the cured product is not added unless a sulfur-based vulcanizing agent (powdered sulfur) is added. It was also found that sex could not be ensured (Comparative Example 2). Further, the cured product using only the bifunctional polyoxypropylene polymer obtained in Synthesis Example 3 as the thiol group-containing polymer also had poor heat resistance (Comparative Example 3).

From the above, in order to obtain a cured composition having good heat resistance in the zinc aluminosilicate curing system, a trifunctional polyoxypropylene polymer having three or more thiol groups in one molecule is blended. Moreover, it is necessary to use a vulcanizing agent and an antioxidant in combination.

Examples 5-6
For 100 parts of the terminal thiol-containing polyoxypropylene polymer obtained in Synthesis Example 1, a phenolic antioxidant (manufactured by ADEKA Co., Ltd., product name: AO-80, chemical name: 3,9-bis [2-- With [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane] A plasticizer, a filler, an ultraviolet shielding agent, and a stabilizer were blended in the ratios shown in Table 2 and then kneaded with a mixer to prepare a main agent. Separately, zinc aluminosilicate as a curing agent, powdered sulfur as a sulfur-based vulcanizer, and a plasticizer were mixed in the ratios shown in Table 2 and then mixed by hand kneading with a spatula to prepare a curing agent paste. The main agent and the curing agent paste were mixed by hand at a ratio of the compounding ratio shown in Table 2, and the heat resistance was evaluated with the obtained hardness test piece and H-type test piece. The results are shown in Table 2.

The color of the cured product of Example 5 using zinc aluminosilicate as the curing agent was white. On the other hand, the cured product prepared by blending 5 parts by weight of manganese dioxide (TypeFA manufactured by Honeywell) as a curing agent with the main agent of Example 5 was dark brown. FIG. 1 shows a cured product of Example 5 using zinc aluminosilicate (right) and a cured product prepared by blending 5 parts by weight of manganese dioxide with the main agent of Example 5 (left). It can be seen that the cured composition of the present invention is a white cured product.

Example 7
For 100 parts of the terminal thiol-containing polyoxypropylene polymer obtained in Synthesis Example 1, a phenolic antioxidant (manufactured by ADEKA Corporation, product name: AO-80, chemical name: 3,9-bis [2-- With [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane] , Thiol ether antioxidant (manufactured by ADEKA Corporation, product name: AO-412S), plasticizer, filler, ultraviolet shielding agent, stabilizer in the ratio shown in Table 2, and then kneaded with a mixer to prepare the main agent. .. Separately, zinc aluminosilicate as a curing agent, powdered sulfur as a sulfur-based vulcanizer, and a plasticizer were mixed in the ratios shown in Table 2 and then mixed by hand kneading with a spatula to prepare a curing agent paste. The main agent and the curing agent paste were mixed by hand at a ratio of the compounding ratio shown in Table 2, and the heat resistance was evaluated with the obtained hardness test piece and H-type test piece. The results are shown in Table 2.

Comparative Example 4
Phenolic antioxidant (manufactured by ADEKA Co., Ltd., product name: AO-80, chemical name: 3,9-bis [2- [3- (3- (3- (3- tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane) and plasticizers, fillers, After blending the ultraviolet shielding agent and the stabilizer in the ratios shown in Table 2, they were kneaded with a mixer to prepare a main agent. Separately, zinc aluminosilicate as a curing agent, powdered sulfur as a sulfur-based vulcanizer, and a plasticizer were mixed in the ratios shown in Table 2 and then mixed by hand kneading with a spatula to prepare a curing agent paste. The main agent and the curing agent paste were mixed by hand at a ratio of the compounding ratio shown in Table 2, and the heat resistance was evaluated with the obtained hardness test piece and H-type test piece. The results are shown in Table 2.

The hardness of the cured product suitable for the building sealant is type E hardness, which is 10 to 40. The strength of the cured product suitable for the building sealant is that the stress at 50% elongation (50% modulus, M ₅₀ ) is 0.05 to 0.30 ^{N / mm 2} .

When a polysulfide polymer (product name: thiocol LP32) is used as a thiol group-containing polymer in the zinc aluminosilicate curing system compound described in Examples 5 to 7 and Comparative Example 4 having an initial hardness of 19 to 35, it is sulfur-based. Even when a vulcanizing agent (powdered sulfur) and a phenolic antioxidant were used in combination, both hardness and modulus could not maintain heat resistance after curing at 90 ° C. for 2 weeks (Comparative Example 4). On the other hand, when the trifunctional polyoxypropylene polymer obtained in Synthesis Example 1 is used as the thiol group-containing polymer after using the antioxidant and the sulfur-based vulcanizing agent in combination, the heat resistance after curing at 90 ° C. for 2 weeks is used. The sex was significantly improved (Example 5). Further, even if the amount of the plasticizer was increased and the hardness and the modulus were lowered, the heat resistance after curing at 90 ° C. for 2 weeks was good (Examples 6 to 7).

Based on the above, in a white and light colored zinc aluminosilicate curing system, a liquid polyether polymer having three or more thiol groups in one molecule, a sulfur-based vulcanizing agent, and an antioxidant can be contained. A curable composition having good heat resistance can be obtained.

Claims (5)

A curable composition containing a liquid polyether polymer having a thiol group at the terminal, zinc aluminosilicate, and a sulfur-based vulcanizing agent, wherein the liquid polyether polymer having a thiol group at the terminal is thiol in one molecule. Contains 3 or more groups, and further
(A) In the main chain,
(A) R ₁ [-(R ₂ O) n] m-
(However, R ₁ is a residue obtained by removing a hydrogen atom from a polyvalent amine or polyhydric alcohol having 12 or less carbon atoms, R ₂ is an alkylene group having 2 to 4 carbon atoms, and n is 6 to 200. Is an integer of, and m is an integer of 3 to 8.)
And the polyoxyalkylene part represented by
(A) -CH ₂ CH (OH) CH _2- S _x-
(However, x is an integer of 1 to 5)
Contains structural units represented by, and at the end,
(C) -CH ₂ CH (OH) CH _2- SH
A curable composition which is a liquid polyether polymer having a structural unit represented by. The curable composition according to claim 1, wherein the liquid polyether polymer having a thiol group at the terminal has a thiol group content of 2.0% by weight or less. The curable composition according to claim 1 or 2, wherein the weight average molecular weight of the liquid polyether polymer having a thiol group at the terminal is in the range of 8,000 to 20,000. The curable composition according to any one of claims 1 to 3, which contains 0.1 to 10 parts by weight of an antioxidant with respect to 100 parts of a liquid polyether polymer having a thiol group at the terminal. The curable composition according to claim 4, wherein the antioxidant is a phenolic antioxidant.

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