JPH0940848A - Elastomer composition having epoxy group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an elastomer composition having high curing rate and giving a cured elastomer having slight compressive residual strain, containing an epoxy-containing elastomer, an imidazole-based compound, trimethylthiourea and isocyanuric acid. SOLUTION: This composition is composed of (A) an elastomer having an epoxy group, (B) an imidazole-based compound of the formula (R1 is a 1-17C alkyl, amino, etc.; R2 is H, a 1-17C alkyl, etc.; R3 and R4 are each H, cyano, etc.) (e.g.; 1-methylimidazole), (C) trimethylthiourea and (D) isocyanuric acid. The component A is usually obtained by copolymerizing an epoxy-containing monomer with a monomer copolymerizable to it. Preferably, the component A is bonded with 0.5-3wt.% an epoxy-containing monomer unit such as glycidyl methacrylate as a crosslinking site. Preferably, 100 pts.wt. of the component A is mixed with 0.5-3 pts.wt. of the component B and respectively 0.3-4 pts.wt. of the component C and the component D.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an elastomer composition having an epoxy group. More specifically, it relates to an elastomer composition having high-speed vulcanizability and processing safety, and giving an elastomer vulcanizate having improved compression set.

[0002]

2. Description of the Related Art As a vulcanizing agent for an elastomer having an epoxy group, a thermally decomposable ammonium salt, a metal salt of dithiocarbamic acid, an amine, a polyamine salt and the like are generally widely used. However, the elastomer vulcanizates using these vulcanizing agents have a relatively large compression set, and further improvement is desired. Further, in the process of manufacturing an elastomer component, high-speed vulcanization for shortening the vulcanization time is desired from the viewpoint of improving productivity and saving energy. Japanese Patent Application Laid-Open No. 63-132925 discloses a vulcanizing composition in which an imidazole compound and a urea derivative compound having a urea bond are used in an elastomer having an epoxy group. Not fast enough.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have aimed to improve the compression set of an elastomer vulcanizate while ensuring high-speed vulcanizability and processing safety, and an elastomer composition having an epoxy group. As a result of various studies on a method for vulcanizing a product, an excellent elastomer composition was found and the present invention was achieved.

[0004]

That is, the present invention is characterized by containing an elastomer having an epoxy group, an imidazole compound represented by the following general formula (1), and trimethylthiourea and isocyanuric acid. The present invention relates to an elastomer composition having an epoxy group.

Embedded image (In the formula, R ₁ represents an alkyl group having 1 to 17 carbon atoms, a substituted alkyl group, an aryl group, a substituted aryl group, an amino group, a cyano group or a mercapto group, and R ₂ represents a hydrogen atom or a carbon number 1
To 17 alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups. R ₃ and R ₄ represent a hydrogen atom, an alkyl group having 1 to 17 carbon atoms or a substituted alkyl group, a cyano group, a hydroxyalkyl group, a carboxyl group, a thiocarbomoyl group, and an imidazolyl group. )

Hereinafter, the present invention will be described in detail. The elastomer of the present invention is obtained by copolymerizing a monomer having an epoxy group and at least one monomer copolymerizable therewith by a known method such as emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization. To be The elastomer in the present invention contains 0.1 to 5.0% by weight, preferably 0.5 to 3.0% by weight of a monomer unit having an epoxy group such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether and methacryl glycidyl ether as a cross-linking seat. Those that are bound by weight% are desirable.

As a monomer copolymerizable with a monomer having an epoxy group, an acrylic acid alkyl ester or an acrylic acid alkoxyalkyl ester is a main component, and a copolymerizable ethylenically unsaturated compound is used as another component. It can be used in the range having.

Examples of alkyl acrylates include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-methylpentyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, n-dodecyl acrylate, n-octadecyl acrylate, cyanomethyl acrylate, 1-cyanoethyl acrylate, 2-cyanoethyl acrylate, 1-cyanopropyl acrylate, 2-cyanopropyl acrylate , 3-cyanopropyl acrylate,
4-cyanobutyl acrylate, 6-cyanohexyl acrylate, 2-ethyl-6-cyanohexyl acrylate, 8-cyanooctyl acrylate and the like can be mentioned.

Further, an alkyl acrylate ester represented by the following general formula (2) is also included.

Embedded image (However, R ₁ is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 3 to 20 carbon atoms, R ₃ is a hydrocarbon group having 1 to 20 carbon atoms or a derivative thereof, and n is an integer of 1 to 20. .)

Examples of the acrylic acid alkoxyalkyl ester include 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2- (n-propoxy) ethyl acrylate, 2- (n-butoxy) ethyl acrylate and 3-methoxypropyl acrylate. , 3-ethoxypropyl acrylate, 2- (n-propoxy) propyl acrylate, 2- (n-butoxy) propyl acrylate and the like.

As the copolymerizable ethylenically unsaturated compound, various compounds can be used if necessary, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid and maleic acid. Compounds having a carboxyl group such as, fumaric acid and itaconic acid, 1,1
-Dihydroperfluoroethyl (meth) acrylate,
1,1-dihydroperfluoropropyl (meth) acrylate, 1,1,5-trihydroperfluorohexyl (meth) acrylate, 1,1,2,2-tetrahydroperfluoropropyl (meth) acrylate, 1,1,
7-trihydroperfluoroheptyl (meth) acrylate, 1,1-dihydroperfluorooctyl (meth)
Acrylate, fluorine-containing acrylic acid ester such as 1,1-dihydroperfluorodecyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2
-Acrylic acid ester having a hydroxyl group such as hydroxypropyl (meth) acrylate and hydroxyethyl (meth) acrylate, acrylic acid ester having a tertiary amino group such as diethylaminoethyl (meth) acrylate and dibutylaminoethyl (meth) acrylate, Methyl methacrylate, methacrylate such as octyl methacrylate, alkyl vinyl ketone such as methyl vinyl ketone, vinyl ethyl ether, vinyl and allyl ether such as allyl methyl ether, styrene, α
-Methylstyrene, chlorostyrene, vinyl aromatic compounds such as vinyltoluene, acrylonitrile, vinyl nitrile such as methacrylonitrile, ethylene, propylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl acetate, vinyl propionate, An alkyl fumarate etc. are mentioned.

Next, as the imidazole compound in the present invention, 1-methylimidazole, 1,2-dimethylimidazole, 1-methyl-2-ethylimidazole,
1-benzyl-2-ethylimidazole, 1-benzyl-2-ethyl-5-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-phenylimidazole-trimellitic acid salt, 1-aminoethylimidazole , 1-aminoethyl-2-methylimidazole, 1-aminoethyl-2-ethylimidazole,
1-Cyanoethyl-2-methylimidazole, 1-Cyanoethyl-2-phenylimidazole, 1-Cyanoethyl-2-ethyl-4-methylimidazole, 1-Cyanoethyl-2-undecylimidazole, 1-Cyanoethyl-2-methylimidazole tri Melitate, 1-cyanoethyl-2-phenylimidazole trimellitate,
1-Cyanoethyl-2-ethyl-4-methylimidazole trimellitate, 1-Cyanoethyl-2-undecyl-imidazole trimellitate, 2,4-diamino-6
-[2'-Methylimidazolyl- (1) '] ethyl-s
-Triazine / isocyanuric acid adduct, 1-cyanoethyl-2-phenyl-4,5-di- (cyanoethoxymethyl) imidazole, N- (2-methylimidazolyl-
1-ethyl) urea, N, N'-bis- (2-methylimidazolyl-1-ethyl) urea, 1- (cyanoethylaminoethyl) -2-methylimidazole, N, N '-[2
-Methylimidazolyl- (1) -ethyl] -adivoyldiamide, N, N '-[2-methylimidazolyl-
(1) -Ethyl] -dodecanedioyldiamide, N,
N '-[2-methylimidazolyl- (1) -ethyl]-
Eicosane dioil diamide, 2,4-diamino-6-
[2'-Methylimidazolyl- (1) ']-ethyl-s
-Triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1) ']-ethyl-s-triazine, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 1,3- Examples thereof include dibenzyl-2-methylimidazolium chloride.

The addition amount of these is preferably 0.2 to 5.0 parts by weight, more preferably 0.5 to 3.0 parts by weight, and less than 0.2 parts by weight with respect to 100 parts by weight of the elastomer. Then, the physical properties of the elastomer vulcanizate are not sufficient,
If it exceeds 5.0 parts by weight, processing safety may be impaired.

The amounts of trimethylthiourea and isocyanuric acid added are preferably 0.1 to 5.0 parts by weight, and 0.3 to 100 parts by weight of the elastomer.
More preferably, the amount is up to 4.0 parts by weight. If it is less than 0.1 part by weight, the vulcanization rate and compression set are not sufficiently improved, and if it exceeds 5.0 parts by weight, problems may occur in molding.

In the present invention, for the purpose of adjusting the vulcanization rate, a curing agent for the epoxy resin, such as a thermally decomposed ammonium salt, an organic acid, an acid anhydride, amines, sulfur and a sulfur compound, is further added. It can be added as long as the effect is not diminished.

Further, when the elastomer composition of the present invention is put to practical use, a reinforcing agent, a filler, a plasticizer, etc. are added to the elastomer composition to carry out molding and vulcanization, thereby achieving its purpose. A corresponding elastomer vulcanizate can be obtained.

The kneading and vulcanization of the elastomer composition according to the present invention can be carried out by the methods generally used in the rubber industry.

The elastomer vulcanizate obtained from the elastomer composition of the present invention is excellent in heat resistance, oil resistance and severe durability and therefore suitable for industrial parts such as belts, hoses, oil seals, gaskets and diaphragms. In particular, it can be expected to improve reliability as automobile parts with particularly stringent quality requirements.

[0018]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Examples 1 to 3 and Comparative Examples 1 to 10 40 kg of a mixed solution of 10 kg of vinyl acetate and 30 kg of n-butyl acrylate, 43 kg of a 4% by weight aqueous solution of partially saponified polyvinyl alcohol, and 60% of sodium acetate were placed in a polymerization vessel.
0 g and glycidyl methacrylate 600 g were added and well mixed in advance with a stirrer to prepare a uniform suspension. After substituting the inside of the polymerization vessel with nitrogen gas, ethylene monomer was injected under pressure from above to adjust the pressure at a polymerization temperature of 45 ° C. to 50 kg / cm ² . Subsequently, a polymerization initiator aqueous solution was separately added from another injection port, and polymerization was performed for about 10 hours.

After the unreacted monomer in the polymer emulsion formed after 12 hours was removed and a 3 wt% borax aqueous solution was added to solidify the emulsion, washing, dehydration, 120-1
After dried on a roll at 30 ° C. for 20 minutes, a sheet-shaped raw rubber was obtained and used for the test.

Next, according to the formulation shown in Table 1, kneading was performed using a 6-inch roll to prepare a sheet having a thickness of 2.3 mm, and this sheet was press-vulcanized at 170 ° C. × 170 ° C.
After 20 minutes (primary vulcanization), vulcanization was performed in a gear oven at 160 ° C. for 4 hours (secondary vulcanization) to prepare a test piece for evaluating physical properties of the elastomer vulcanizate. The physical property test of primary vulcanizates and secondary vulcanizates is JIS K6301.
According to JIS K63
The measurement results are shown in Table 2.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

The epoxy group-containing elastomer composition of the present invention has a high vulcanization rate as is clear from the examples, and the compression set of the elastomer vulcanizate after primary vulcanization is improved. The primary vulcanizates and secondary vulcanizates have excellent tensile properties (tensile strength / elongation) and compression set balance.

Claims (1)

[Claims] 1. An epoxy group-containing elastomer composition comprising an epoxy group-containing elastomer, an imidazole compound represented by the following general formula (1), and trimethylthiourea and isocyanuric acid. Embedded image (In the formula, R ₁ represents an alkyl group having 1 to 17 carbon atoms, a substituted alkyl group, an aryl group, a substituted aryl group, an amino group, a cyano group or a mercapto group, and R ₂ represents a hydrogen atom or a carbon number 1
To 17 alkyl groups, substituted alkyl groups, aryl groups, and substituted aryl groups. R ₃ and R ₄ represent a hydrogen atom, an alkyl group having 1 to 17 carbon atoms or a substituted alkyl group, a cyano group, a hydroxyalkyl group, a carboxyl group, a thiocarbomoyl group, and an imidazolyl group. )