JPH0794588B2 - Acrylate elastomer vulcanizing composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy group-containing acrylate elastomer vulcanizing composition, and more specifically, it has excellent scorch stability and mechanical properties, The present invention relates to an epoxy group-containing acrylate elastomer vulcanizing composition having excellent properties such as heat aging resistance and compression set.

(Problems to be Solved by Conventional Techniques and Inventions) Acrylate elastomers are known as elastomers having excellent heat resistance, oil resistance, weather resistance and the like. However, since the main chain does not have a double bond, acrylate elastomers containing an epoxy group, a carboxyl group, an active chlorine group or the like as a crosslinking point have been put to practical use.

Conventionally, polyamine, diamine carbamate, ammonium organic carboxylate, dithiocarbamate and the like have been generally used as a vulcanization system for an acrylate elastomer containing an epoxy group. However,
The use of polyamines and diamine carbamates lacks stability against early vulcanization, and thus has a drawback that scorching is likely to occur during the kneading process. Further, when using ammonium organic carboxylate or dithiocarbamate, stability against early vulcanization is excellent, but there is a drawback that good compression set is difficult to obtain even after post-vulcanization for a long time. is there.

Various vulcanization methods have been proposed to improve these drawbacks, for example, JP-A-57-177044 and JP-A-
Japanese Patent Application Laid-Open No. 7-177045 discloses a vulcanization system using a guanidine compound, and a guanidine compound, sulfur, and a sulfur compound for an epoxy group-containing acrylate elastomer. However, although these vulcanization systems have excellent stability against early vulcanization, they have the drawback of poor compression set.

The present inventors have made extensive studies on various vulcanization systems in order to improve these drawbacks, and as a result, a low-molecular organic compound having a specific bond in the molecule and a guanidine-based acrylate-based elastomer By using the compound as a vulcanizing system, it was found that a vulcanized product having excellent scorch stability, mechanical properties, heat aging resistance, compression set and the like can be obtained, and the present invention was completed. It came to.

(Means for Solving Problems) That is, the present invention provides an epoxy group-containing acrylate-based elastomer having (1) a molecule The present invention provides an acrylate elastomer vulcanizing composition comprising an organic compound having two or more (wherein X and Y represent an oxygen atom or a sulfur atom) and (2) a guanidine compound.

The epoxy group-containing acrylate elastomer used in the present invention is usually selected from the range of 0.1 to 10% by weight, preferably 0.5 to 3% by weight, of an epoxy group-containing monomer as a crosslinking point, and alkyl or alkoxy acrylate. 30 to 99.9% by weight of at least one monomer, and at least one monomer having a copolymerizable terminal vinyl or vinylidene group copolymerizable with these monomers 0 to
It is an elastomer obtained by copolymerizing 70% by weight with a known polymerization method.

Examples of the epoxy group-containing monomer used as the cross-linking point include glycidyl acrylate, glycidyl methacrylate, vinyl glycidyl ether, allyl glycidyl ether, methallyl glycidyl ether, and the like. Among these, glycidyl acrylate and glycidyl are particularly preferable. Methacrylate is preferred.

Examples of the alkyl acrylate copolymerizable with the epoxy group-containing monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate,
Alkyl acrylates in which the alkyl group has 1 to 8 carbon atoms, such as 2-ethylhexyl acrylate and n-octyl acrylate are mentioned. Examples of alkoxyalkyl acrylates include alkoxy groups such as methoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, and methoxyethoxyethyl acrylate, and alkoxyalkyl acrylates in which the alkylene group has 1 to 4 carbon atoms. Can be mentioned.

Examples of the monomer having a terminal vinyl and vinylidene group copolymerizable with the epoxy group-containing monomer include vinyl acetate, vinyl propionate, vinyl butyrate nadonovinyl ester; α-such as ethylene, propylene and 1-butene. Mono-olefins; vinyl ketones such as methyl vinyl ketone and ethyl vinyl ketone; vinyl aromatic compounds such as styrene, α-methyl styrene and vinyl toluene; vinyl ethers such as vinyl ethyl ether and allyl methyl ether; vinyl and vinylidene such as acrylonitrile and methacrylonitrile. Nitrile; vinyl monomers having hydroxyl groups such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate; 2-cyanoethyl acrylate, 3-cyanopropyl acrylate, 4-cyanobutyl acrylate, etc. Cyano-substituted vinyl monomers; vinyl and vinylidene amides such as acrylamide, methacrylamide, N-methylol acrylamide; vinylidene acrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate; conjugated dienes such as butadiene and isoprene. ,
These monomers may be used alone or in combination of two or more with alkyl or alkoxyalkyl acrylate.

Examples of the acrylate elastomer containing an epoxy group include epoxy group-containing acrylate copolymer elastomer, epoxy group-containing ethylene-acrylate copolymer elastomer, epoxy group-containing ethylene-vinyl acetate-acrylate copolymer elastomer, epoxy group-containing Acrylate-acrylonitrile copolymer elastomer, epoxy group-containing acrylate-vinyl acetate-acrylonitrile copolymer elastomer, epoxy group-containing acrylate-butadiene-acrylonitrile copolymer elastomer, and the like, but are not particularly limited to these elastomers. Absent.

In the molecule used as the vulcanizing agent in the present invention (In the formula, X and represent an oxygen atom or a sulfur atom)
Organic compounds having one or more of them are a heterocyclic compound having the bond, an aromatic compound and a chain urea derivative. In addition, when the number of the bonds is two or more, there are two or more of the bonds independently. As described above, a case in which two or more such bonds are contained as a unit is included. Further, the bond may be present outside the ring as a substituent of the heterocyclic compound. Moreover, even if X and Y in the bond are the same,
May be different.

Examples of the heterocyclic compound include parabanic acid, alloxan, alloxanthin, alloxan-5-oxime, barbituric acid, 5-hydroxybarbituric acid, 5-benzalbarbituric acid, 5-aminobarbituric acid, 5-hydroxyiminobarbi. Thulic acid, 5,5-diethylbarbituric acid, 5-ethyl-5-phenylbarbituric acid, 5- (1-methylbutyl) -5- (allyl) barbituric acid, 5,5-diallylbarbituric acid, isocyanuric acid , Pseudouric acid, etc. and these compounds In which the oxygen atom of is substituted with a sulfur atom, 2,4-dithiobarbituric acid, 2-thiobarbituric acid and the like can be mentioned.

Aromatic compounds include pyromellitic acid diimides, mellitic acid triimides, 1,4,5,8-naphthaldiimide and the like and their corresponding thioimides.

Examples of the urea derivative include triuret, 1-methyl triuret, 1,1-diethyl triuret, tetrauret and the like, and their corresponding thiouret.

These compounds can be added and mixed at the time of the polymerization reaction of the epoxy group-containing elastomer or at the time of the completion of the polymerization, or added and mixed together with other compounding agents such as a reinforcing agent to the elastomer by a kneader usually used in the rubber industry. can do.

The amount of these compounds used is usually 0.1 to 10 parts by weight per 100 parts by weight of the elastomer, from the viewpoint of the vulcanization rate, mechanical properties of the vulcanizate, compression set, etc. To be selected. If it is less than 0.1 part by weight, the crosslink density is too low to be a practical vulcanizate. On the other hand, if it is used in excess of 10 parts by weight, the vulcanization rate will be remarkably slow and a vulcanizate that can be put to practical use cannot be obtained. Preferably
0.2 to 5 parts by weight.

Examples of the guanidine compound used in combination with the above compound in the present invention include guanidine, aminoguanidine, 1,1,3,3-tetramethylguanidine, n-dodecylguanidine, and 1,6.
-Diguanidinohexane, methylolguanidine, dimethylolguanidine, guanylurea, biguanide, 1-
Phenylguanidine, 1,3-diphenylguanidine, 1,3
-Di-o-tolyl guanidine, triphenyl guanidine, 1-o-tolyl biguanide, 1-benzyl-2,3-
Specific examples thereof include dimethylguanidine and cyanguanidine.

These guanidine compounds can be used alone or in combination of two or more, and are usually used in a proportion of 0.1 to 10 parts by weight with respect to 100 parts by weight of the epoxy group-containing acrylate elastomer. The use ratio of these compounds to the epoxy group-containing acrylate elastomer is vulcanization rate,
Mechanical properties of the vulcanizate, from the viewpoint of compression set, etc. are selected as preferable ranges within the above range, respectively, while less than 0.1 parts by weight vulcanization hardly proceeds, while exceeding 10 parts by weight. When used as a vulcanizate, the vulcanization speed increases and the processing stability is impaired. It is preferably 0.1 to 5 parts by weight.

The vulcanized composition of the present invention comprises a vulcanized epoxy group-containing acrylate elastomer, a vulcanized resin, a reinforcing agent, a filler, a plasticizer, a stabilizer, a processing aid and the like, which are commonly used in the rubber industry, in rolls and Banbury. It is prepared by mixing with a conventional kneader such as. The composition is molded into a shape according to the purpose and is vulcanized to be a final product.

Vulcanization is usually carried out at temperatures above 120 ° C, preferably 150
1 to 30 minutes at a temperature of about ℃ ~ 220 ℃, post-vulcanization 1
It is carried out at a temperature of about 50 ° C to 200 ° C for about 1 to 24 hours.

The vulcanizate of epoxy machine-containing acrylate elastomer obtained by the vulcanization system of the present invention has heat aging resistance, oil resistance,
Since various properties such as compression set are excellent, it is widely and effectively used for various sealing materials (gaskets, O-rings, packings, oil seals), various hoses, belts, etc. by utilizing these properties. be able to.

(Examples) The present invention will be specifically described below with reference to Examples. Note that%
And parts are by weight.

Example 1. Epoxy group-containing acrylate elastomer synthesized by a conventional emulsion polymerization method [Composition (%) determined from ¹³ C-NMR chemical shift: ethyl acrylate 48.7, butyl acrylate 31, methoxyethyl acrylate 19, glycidyl methacrylate 1.3] 100 parts, stearic acid 1 part, MAF carbon black (Tokai Carbon Co., Ltd. product, Seast 116) 60
Parts, 2 parts of an amine anti-aging agent (Nowgard 445 manufactured by Uniroyal Co., Ltd.), and predetermined amounts of various compounding agents shown in Table 1 were kneaded with a 6-inch roll to prepare a compounding agent.

The Mooney scorch time was measured according to JIS K-6300 for each of the obtained formulations. In addition, each formulation was
After press vulcanization for 0 minutes, post vulcanization was performed for 4 hours in a gear oven at 150 ° C. About each vulcanizate obtained
Vulcanization properties were measured according to JIS K-6301. The results obtained are shown in Table 2.

From these results, the vulcanization system of the present invention is mechanically vulcanized even at a short press vulcanization time of 170 ° C. for 20 minutes as compared with the conventionally used vulcanization system (Comparative Examples 11 and 12). It has excellent properties and also has an excellent compression set. Therefore, it can be seen that the post-vulcanization can be omitted or the post-vulcanization time can be significantly shortened. In addition, the imidodicarbonyl group in the molecule It can also be seen that the vulcanization performance of the compound having only one (Comparative Example 10) is poor.

Example 2 Epoxy group-containing acrylate elastomer 100 described above
Parts, stearic acid 1 part, MAF carbon black 60 parts, amine-based anti-aging agent (Uniroyal product Now Guard 445)
2 parts and a predetermined amount of the vulcanizing agent shown in Table 3 were kneaded with a 6-inch roll to prepare a blend.

Mooney scorch time was measured for each of the resulting formulations. Further, each compound was press-vulcanized at 170 ° C. for 20 minutes and then post-vulcanized in a gear oven at 150 ° C. for 4 hours. Various physical properties of the obtained vulcanized products were measured in the same manner as in Example 1. The results obtained are shown in Table 4.

From these results, increasing the amount of the guanidine-based compound accelerates the scorch time, and when the imidedicarbonyl group-containing compound is excessively blended, the vulcanization rate becomes slow and the physical properties of the vulcanizate are impaired. It is understood that when either one of the dicarbonyl group-containing compounds is lacking (Comparative Examples 28 and 29), various properties of the vulcanizate are impaired.

It is also found that various guanidine compounds can be used as the vulcanization system of the present invention.

Example 3 Epoxy group-containing ethylene synthesized by a conventional high-pressure polymerization method
Acrylate copolymer elastomer [composition (%) obtained from ¹³ C-NMR chemical shift: 40 parts of ethylene, 58.2 of methyl acrylate, 1.8 of glycidyl methacrylate 1.8], 1 part of stearic acid, 45 parts of MAF carbon black, amine anti-aging The compounding amount was prepared by kneading 2 parts of the agent (Nowroyal 445, Uniroyal product) and a predetermined amount of the vulcanizing agent shown in Table 5 with a 6-inch roll.

After measuring the Mooney scorch time of the obtained compound, each vulcanized product was prepared under the same conditions as in Example 1 and various physical properties were measured. The results obtained are shown in Table 6.

Claims (1)

[Claims] 1. An epoxy group-containing acrylate elastomer, (1) in a molecule An acrylate-based elastomer vulcanization composition obtained by blending an organic compound having two or more (wherein X and Y represent an oxygen atom or a sulfur atom) and (2) a guanidine-based compound.