JP2013129768A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition having high hardness of a cured material, high stress at 100% elongation in dumbbell tensile measurement, high maximum tensile stress and high elongation at maximum load.SOLUTION: The curable composition contains a liquid polysulfide polymer, an oxidant and a filler, has a hardness (Shore A) of ≥45 in measurement of a composition cured at 70°C for 2 hr under the atmosphere of 23°C, and has 3,500 of the value of product of: the stress, M(N/mm) in the dumbbell tensile measurement; a maximumtensile stress, T(N/mm); and an elongation at maximum load, E(%). The liquid polysulfide polymer is represented by HS-(R-S)-R-SH (wherein x is an integer of 1 to 5, provided that the average value of x is 1 to 2.5; n is an integer of 1 to 200; and R is a di- or tri-valent organic group including -OCHO-).

Description

  The present invention relates to a curable composition containing a liquid polysulfide polymer, an oxidizing agent, and a filler, and relates to a curable composition having a high hardness, a maximum point stress in a tensile test, and a large elongation during the tensile test. .

  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 polysulfide polymer contains sulfur in the main chain of the molecule and does not contain double bonds, so it has excellent oil resistance, weather resistance, water tightness, and air tightness. In addition, it is widely used as a sealing material, an adhesive and a paint because of its excellent characteristics and good adhesion.

  It is well known that a large number of oil sulfide-resistant polysulfide sealing materials are used as sealing materials for covering the joint surface by bolts, rivets and welding in aircraft bodies. In order to cope with a large weight applied to a joint portion of an aircraft sealing material, and to maintain high oil resistance, it is preferable that the sealing material has a higher hardness. On the other hand, high elongation is also required in order to follow the displacement of the adherend due to vibration of the airframe or temperature difference. However, when the hardness of the sealing material is increased, the elongation decreases, and it is necessary to use a special compounding agent for the purpose of balancing conflicting properties. However, in order to reduce the components of the compounding agent as much as possible, it has been desired to improve the properties of the polymer such as high hardness, high strength and high elongation.

  As a method for producing a liquid polysulfide polymer to be the above-mentioned sealing material base polymer, the most common method is to obtain a liquid polymer via solid polysulfide described in US Pat. No. 2,466,963 (see Patent Document 1). A production method that does not include the formation of solid polysulfide using a phase transfer catalyst has also been reported (see Patent Document 2).

  In addition, as a commercial product of liquid polysulfide polymer, various varieties having different molecular weights and crosslinking amounts known as “Thiocol LP” manufactured by Toray Fine Chemical and “ThioplastG” manufactured by AkzoNobel are sold.

US Pat. No. 2,466,963 Japanese Patent No. 4227787

  An object of the present invention is to provide a curable composition having a large hardness, a stress at 100% elongation during dumbbell tensile measurement, a large maximum tensile stress, and a large elongation at the maximum load.

The curable composition of the present invention contains a liquid polysulfide polymer, an oxidizing agent, and a filler, and is cured at 70 ° C. for 2 hours and measured in an atmosphere at 23 ° C., and has a hardness (Shore A) of 45 or more and a dumbbell tensile measurement. The value of the product of M ₁₀₀ (N / mm ² ), maximum tensile stress T _max (N / mm ² ) at time and elongation E _max (%) at maximum load is 3500 or more, and the liquid polysulfide polymer is
HS- (R- _Sx ) _n- R-SH
(Where 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 or trivalent organic group containing —OCH ₂ O—). It is the curable composition shown.

  The curable composition of the present invention is excellent in oil resistance, weather resistance, water tightness, and air tightness as in the case of a curable composition using a conventional liquid polysulfide polymer, and further, a curable composition using a conventional liquid polysulfide polymer. Compared to the composition, it has the characteristics that the hardness of the cured product, the stress at 100% elongation during dumbbell tensile measurement, the maximum tensile stress can be increased, and the elongation at maximum load can be increased. This characteristic greatly contributes to the improvement of characteristics when a sealing material is blended.

  Therefore, the curable composition of the present invention can be used for adhesives, sealing materials, potting materials, coating materials, resin modifiers, primers, and the like, especially for civil engineering / architecture, electric / electronic, and vehicle use. And 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, so that it is particularly suitable for an aircraft sealing material.

  Hereinafter, the present invention will be described in detail.

The liquid polysulfide polymer used in the curable composition of the present invention is a liquid polymer represented by the following general formula:
HS- (R- _Sx ) _n- R-SH
(However, R is a divalent or trivalent organic group containing a —O—CH ₂ —O— bond, n is an integer of 1 to 200, and preferably an integer of 1 to 50. x is 1 to 5) (The average value of x is 1 to 2.5.)
R is preferably an organic group containing a —O—CH ₂ —O— bond and a branched alkylene group. The branched alkylene group is preferably 0 to 70 mol% based on the number of moles of —O—CH ₂ —O— bonds.

R is preferably
_{-C 2 H 4 -O-CH 2} -O-C 2 H 4 -
Is contained in an amount of 50 mol% or more. More preferably,
_{-C 2 H 4 -O-CH 2} -O-C 2 H 4 -
70 mol% or more.

When R is an organic group containing a branched alkylene group, the branched alkylene group is preferably 0 to 70 mol% with respect to the number of moles of —O—CH ₂ —O— bonds.

  The branched alkylene group is preferably a polyfunctional component derived from a trihalo organic compound,

It is an organic group shown by. A preferred branched trihalo organic compound is a trihaloalkyl compound, and a more preferred branched trihalo organic compound is trihalopropane. Preferred halogen atoms of trihalopropane are chlorine, bromine, and iodine, and more preferred halogen atoms are chlorine atoms.

  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. It is liquid at room temperature, and the number average molecular weight is preferably 500 to 50,000, and more preferably 1,000 to 10,000.

  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, the polymer and the curable composition have the effects of low viscosity, low glass transition temperature, and high heat resistance, as compared with commercially available conventional liquid polysulfide polymers. .

  As a conventional method for producing a liquid polysulfide polymer containing two or more thiol groups in one molecule, a method for obtaining a liquid polymer via solid polysulfide described in US Pat. No. 2,466,963 is the most common. A production method that does not involve the formation of solid polysulfide using a phase transfer catalyst has been reported (Japanese Patent No. 4227787). The curable composition obtained in the present invention is preferably produced without the formation of solid polysulfide. Particularly preferably, by using a liquid polysulfide polymer produced by the method described in Japanese Patent No. 4227787, crosslinking and molecular weight distribution can be controlled easily and precisely, and the cured product has a hardness representing hardness and a stress at 100% elongation. And having a high maximum tensile stress and a large elongation at the time of maximum load, which can improve the contradictory effects.

  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 is obtained by reacting the terminal halide described in Japanese Patent Application No. 2011-167330 with sodium hydrosulfide according to Japanese Patent Publication No. 47-48279 and JP-A-1-278557. You can also.

The liquid polysulfide polymer used in the present invention has an average value x of 1 to 2.5 of HS- (R- _Sx ) _n- R-SH, and the sulfur content x is sodium sulfide at the time of charging. It can be prepared by mixing sodium monosulfide (Na ₂ S) and polysulfide (Na ₂ S _{x, where} x is 2 or more) at an arbitrary ratio. 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.

  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 liquid polysulfide polymers. If it is less than 1 part by weight, a sufficient curing rate cannot be obtained, and if it exceeds 50 parts by weight, it is not preferred because it is cured immediately after mixing and workability cannot be obtained. More preferably, it is 1-30 weight part, More preferably, it is 1-20 weight part, More preferably, it is 5-15 weight part.

  In the present invention, examples of the filler include inorganic fillers such as calcium carbonate, aluminum oxide, aluminum hydroxide, silica, silicate, sulfate, and carbon black, and carbon black is preferable.

  It is preferable that the addition part of a filler is 0.1-500 weight part with respect to 100 weight part of liquid polysulfide polymers. 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, it is 1-300 weight part, More preferably, it is 10-200 weight part, More preferably, it is 30-60 weight part.

  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, hydrocarbon plasticizer described in JP-A-2004-51918, and halogen-terminated sulfur-containing polymer described in Japanese Patent Application No. 2011-167330. The plasticizer is preferably a phthalate ester, chlorinated paraffin, dipropylene glycol dibenzoate, a halogen-terminated sulfur-containing polymer.

  The number of parts added of the plasticizer is set by the strength and elongation of the cured product and the design of the viscosity before curing, but is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the liquid polysulfide polymer. If it exceeds 100 parts by weight, the amount of non-reactive liquid may increase and the hardness may not be maintained. More preferably, it is 1-50 weight part, More preferably, it is 1-30 weight part.

  Curing accelerators 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 addition parts of the curing accelerator is set depending on the curing rate of the curable composition and further the use temperature, but is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the liquid polysulfide polymer. When the amount exceeds 10 parts by weight, the remaining accelerator that was not involved in the reaction may deteriorate the performance of the cured product. More preferably, it is 1-5 weight part, More preferably, it is 1-3 weight part.

  The curable composition of the present invention comprises a polyfunctional crosslinking agent, an adhesion promoter, a polymer, a curing agent, a filler, the above plasticizer, and a curing accelerator, depending on the intended use of the curable composition. You may contain at least 1 sort (s) each of a ultraviolet absorber, antioxidant, tackifier, rubber | gum / elastomer, fungicidal agent, corrosion inhibitor, a pigment, a masking agent, or an additive which has a different effect | action.

  Examples of the multifunctional crosslinking agent include trimethylolpropane trimercaptopropionate, trimethylolpropane trimercaptoacetate, pentaerythritol-tetrakis-3-mercaptopropionate, and the like. Two or more polyfunctional crosslinking agents may be used.

  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. Further, a terminal trimethoxysilane-modified polysulfide polymer synthesized by reacting polysulfide polymer “thiocol LP-3” and 3-gridoxypropyltrimethoxysilane described in JP-A-6-271833 is also used as a silane coupling agent. Can do. 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.

In the curable composition of the present invention, the mixture was cured at 70 ° C. for 2 hours to prepare a sheet-like curable composition having a thickness of 2 mm, and the obtained sheet was placed in an atmosphere of 23 ° C. and 50% RH for 1 hour. Heat is removed, and the hardness (Shore A) when measuring the hardness and dumbbell tensile properties in an atmosphere of 23 ° C. is 45 or more, and M ₁₀₀ (N / mm ² ) at the time of dumbbell tensile measurement is the maximum. The product of the tensile stress T _max (N / mm ² ) and the elongation rate E _max (%) at the maximum load is 3500 or more. The hardness (Shore A) is preferably 45 to 90, and more preferably 45 to 65. In addition, the product value of M ₁₀₀ (N / mm ² ), maximum tensile stress T _max (N / mm ² ), and elongation rate E _max (%) at the maximum load when dumbbell tensile measurement is preferably 3500 It is 10,000, More preferably, it is 3500-7000.

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

Measurement of viscosity The sample viscosity at 25 ° C was measured using a viscometer U-EII manufactured by Toki Sangyo.

Measurement of SH content A sample was dissolved in a mixed solution of toluene and pyridine, and after adding an aqueous potassium iodide solution, titration was performed using an iodine standard solution.

Measurement of Dumbbell Tensile Properties Three dumbbell specimens were cut out from a sheet-like cured product having a diameter of about 120 mm × 2 mm using a punching blade adjusted to a dumbbell shape No. 5 described in JIS K6251. A 20 mm mark was attached to the cut dumbbell test piece, and a tensile test was conducted at 500 mm / min using Tensilon RTA-500 manufactured by Orientec. In the dumbbell tensile measurement, M ₁₀₀ (N / mm ² ) is the stress at 100% elongation (when the marked line becomes 40 mm), T _max (N / mm ² ) is the maximum tensile stress, and E _max (%) is Elongation at maximum load. The number of tests was 1 sample n = 3, and the average value was the measurement result.

Measurement of Hardness Three dumbbell test pieces were cut out from a sheet-like cured product having a diameter of about 110 mm × 2 mm, and the remaining four sheets were stacked to prepare a block-like cured product having a thickness of about 50 mm × about 50 mm × 8 mm. The hardness of the cured product adjusted to a block shape of 8 mm thickness was measured with a type A durometer described in JIS K6253 in an atmosphere of 23 ° C.

Synthesis example 1
Using a 1 L separable flask, 844.0 g of sodium polysulfide aqueous solution (2.17 mol / L), 2.6 g of tetrabutylammonium bromide 50 wt% aqueous solution, 11.4 g of 42% sodium hydrosulfide aqueous solution, 276. 0 g of bis (2-chloroethyl) formal and 0.46 g of 1,2,3-trichloropropane were reacted to obtain a light yellow transparent liquid polysulfide polymer without passing through solid polysulfide. The obtained polymer had a viscosity of 43.7 Pa · s and an SH content of 1.5%.

Synthesis example 2
Using a 1 L separable flask, 848.2 g sodium polysulfide aqueous solution (2.17 mol / L), 2.6 g tetrabutylammonium bromide 50 wt% aqueous solution, 11.9 g 42% sodium hydrosulfide aqueous solution, 275. 5 g of bis (2-chloroethyl) formal and 1.17 g of 1,2,3-trichloropropane were reacted to obtain a light yellow transparent liquid polysulfide polymer without passing through the solid polysulfide. The obtained polymer had a viscosity of 44.3 Pa · s and an SH content of 1.7%.

Synthesis example 3
Using a 1 L separable flask, 823.1 g of sodium polysulfide aqueous solution (2.17 mol / L), 2.6 g of tetrabutylammonium bromide 50 wt% aqueous solution, 22.7 g of 42% sodium hydrosulfide aqueous solution, 275. 5 g of bis (2-chloroethyl) formal and 1.17 g of 1,2,3-trichloropropane were reacted to obtain a light yellow transparent liquid polysulfide polymer without passing through the solid polysulfide. The obtained polymer had a viscosity of 10.8 Pa · s and an SH content of 3.0%.

Example 1
35 parts by weight of SRF carbon and 9 parts by weight of manganese dioxide (TYPE-FA manufactured by Honeywell) are added to 100 parts by weight of the polymer of Synthesis Example 1, and 9 parts by weight of butyl benzyl phthalate so that the manganese dioxide becomes a paste. Then, 0.45 parts by weight of tetrabutylthiuram disulfide was used as an additive and kneaded using a three-roll mill.

A total of 40 g of the mixture was sandwiched between iron plates adjusted to have a gap of 2 mm, and heated and cured at 70 ° C. for 2 hours to prepare a 2 mm thick sheet-like cured composition. The obtained sheet was left to stand for 1 hour in an atmosphere of 23 ° C. and 50% RH to remove heat, and the hardness and dumbbell tensile properties were measured in an atmosphere of 23 ° C. Value of the product obtained result and _{M 100} and _{T max} and _{E max} are shown in Table 1.

Examples 2 and 3
The mixture was cured for 2 hours at 70 ° C. in the same manner as in Example 1 except that the polymers of Synthesis Examples 2 and 3 were used instead of the polymer of Synthesis Example 1 of Example 1. A composition was prepared, and the obtained sheet was left for 1 hour in an atmosphere of 23 ° C. and 50% RH to remove heat, and the hardness and dumbbell tensile properties were measured in an atmosphere of 23 ° C. Value of the product obtained result and _{M 100} and _{T max} and _{E max} are shown in Table 1.

Comparative Examples 1-6
As a polymer produced by a method that uses a conventional solid polysulfide instead of the polymer of Synthesis Example 1 of Example 1, a commercially available product “Thicol LP-55 (viscosity 43.4 Pa · s, SH content) manufactured by Toray Fine Chemical Co., Ltd. 1.7%) ”,“ Thiocol LP-32 (viscosity 44.0 Pa · s, SH content 1.8%) ”“ Thiocol LP-980 (viscosity 11.2 Pa · s, SH content 2.9%) ”, “Thioplast G10 (viscosity 53.1 Pa · s, SH content 1.6%)”, “Thioplast G112 (viscosity 58.7 Pa · s, SH content 1.6%)” “Thioplast G22 (viscosity 13.3 Pa · s) manufactured by AkzoNobel s, SH content 2.7%) ”and the mixture was cured at 70 ° C. for 2 hours in the same manner as in Example 1 to obtain a 2 mm thick sheet. To prepare a curable composition, heat is removed and left for 1 hour and the resulting sheet of RH 23 ° C. 50% to cut 囲下, hardness, dumbbell tensile properties were measured in an atmosphere of 23 ° C.. Value of the product obtained result and _{M 100} and _{T max} and _{E max} are shown in Table 1.

As shown in Table 1, the curable compositions (Examples 1 to 3) of the present invention are curable compositions (Comparative Examples 1 to 6) using a liquid polymer produced by a method via a conventional solid polysulfide. ) Is higher than 45 and the product of M ₁₀₀ , T _max and E _max is higher than 3500. Thus, the curable composition of the present invention has high hardness and high elongation, and can improve contradictory properties.

Claims (6)

It contains a liquid polysulfide polymer, an oxidizing agent, and a filler, and is cured at 70 ° C. for 2 hours and measured in a 23 ° C. atmosphere. The hardness (Shore A) is 45 or more, and M ₁₀₀ (N / mm ² at the time of dumbbell tensile measurement) ), The maximum tensile stress T _max (N / mm ² ) and the elongation rate E _max (%) at the maximum load is 3500 or more,
Liquid polysulfide polymer
HS- (R- _Sx ) _n- R-SH
(Where 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 or trivalent organic group containing —OCH ₂ O—). The curable composition shown. The curable composition according to claim 1, wherein the oxidizing agent is manganese dioxide. The curable composition according to claim 1 or 2, wherein the filler contains at least one of carbon black, calcium carbonate, and silica. The curable composition according to any one of claims 1 to 3, comprising a plasticizer and a curing accelerator. The curable composition according to claim 4, wherein the plasticizer is at least one of phthalate ester, chlorinated paraffin, dipropylene glycol dibenzoate, and halogen-terminated sulfur-containing polymer. The curable composition according to claim 4 or 5, wherein the curing accelerator is at least one of a thiuram vulcanization accelerator and a guanidine vulcanization accelerator.