JP2800301B2 - Copolymer rubber vulcanization composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a vulcanizable copolymer rubber composition which vulcanizes quickly and gives a vulcanizate having excellent heat resistance, oil resistance and cold resistance. Things.

[Prior art] In recent years, as a result of improvements in engines and the like aimed at improving exhaust gas regulations and performance of automobiles, the use environment of rubber parts used has become increasingly severe, and more excellent heat resistance and oil resistance. There is a demand for rubber materials having properties.

A copolymer rubber containing an acrylic acid ester or methacrylic acid ester of a cyano group-containing caprolactone oligomer as one component has excellent oil resistance and heat resistance. However, the copolymer having an epoxy group introduced as a crosslinking point is an organic ammonium salt of an organic carboxylic acid such as ammonium benzoate, which is conventionally known as a vulcanizing agent for an epoxy group-containing acrylic rubber. It is possible to vulcanize by using a metal salt of dialkyl carbamic acid such as zinc dimethyldithiocarbamate as a vulcanizing agent, but it takes a long time to obtain a vulcanized product having a low vulcanizing rate and satisfactory physical properties. There is a problem that post-curing is required.

[Problems to be Solved by the Invention] The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have found that an acrylate or methacrylate of an epoxy group-containing monomer and a cyano group-containing caprolactone oligomer. Is a vulcanized rubber having satisfactory physical properties in a short vulcanization time by using a quaternary ammonium salt or a quaternary phosphonium salt as a vulcanizing agent. Found to give.

[Means for Solving the Problems] The present invention provides 1) the following formula (I) (Where R ¹ is hydrogen or a methyl group, R ² is a cyano group-substituted alkyl group, n is an integer of 1 or more, and the number average is 1 to 10.) Containing caprolactone oligomer acrylate or methacrylate 0.5-99.
9% by weight, 2) 0.1 to 10% by weight of an epoxy group-containing monomer, and 3) 100 parts by weight of a copolymer rubber having a polymerization composition of 0 to 99.4% by weight of a monomer copolymerizable therewith. A vulcanizable rubber composition comprising 0.1 to 10 parts by weight of a quaternary ammonium salt or a quaternary phosphonium salt.

The copolymer rubber used in the present invention is represented by the following formula (A):
Acrylic ester or methacrylic ester of a cyano group-containing caprolactone oligomer represented by 0.5 to 9
It has a polymerization composition of 9.9% by weight, (B) an epoxy group-containing monomer, 0.1 to 10% by weight, (C) a monomer copolymerizable with the above (A) and (B), and 0 to 99.4% by weight. And a glass transition point of room temperature, preferably 0 ° C. or lower.

The acrylate or methacrylate of the cyano group-containing caprolactone oligomer of the component (A) is
It is a compound represented by the formula (I). Examples of R2 in the formula (I) include a 2-cyanoethyl group, a 2-cyanopropyl group, a 3-cyanopropyl group, a 2-cyanobutyl group,
Examples thereof include a cyanobutyl group, and a 2-cyanoethyl group and a 2-cyanopropyl group are particularly preferable. The acrylate or methacrylate of the cyano group-containing caprolactone oligomer is disclosed in, for example, JP-A-1-132611.
Can be synthesized by the method described in (1).

Examples of the epoxy group-containing monomer of the component (B) include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, vinyl glycidyl ether and the like. These can be used alone or in combination of two or more.

Examples of the monomer copolymerizable with the acrylate or methacrylate of the cyano group-containing caprolactone oligomer of component (C) and the epoxy group-containing monomer include methyl acrylate, ethyl acrylate, and acrylic acid. n-butyl, iso-butyl acrylate, tert-butyl acrylate, propyl acrylate, n-acrylate
Octyl, 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, etc. alkyl acrylates having 1 to 20 carbon atoms in the alkyl group: methoxymethyl acrylate, methoxyethyl acrylate, ethoxycetyl acrylate, butoxy acrylate Alkoxyalkyl esters having 1 to 4 carbon atoms of an alkoxyl group or an alkylene group such as ethyl and methoxyethoxyethyl acrylate: methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, methacrylic acid Alkyl methacrylate having an alkyl group having 1 to 20 carbon atoms such as stearyl: methoxymethyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate , Methacrylic acid alkoxyalkyl esters such as methoxyethoxyethyl methacrylate: 2-cyanoethyl acrylate, 3-cyanopropyl acrylate, 2-cyanoethyl methacrylate, 3 methacrylic acid
A cyanoalkyl ester of acrylic acid or methacrylic acid such as cyanopropyl: acrylic acid or methacrylic acid such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate or 2-hydroxypropyl methacrylate; Hydroxyalkyl ester: (Where R ³ is a hydrogen or methyl group, R ⁴ is a C 1-8
Is an alkyl group or an alkoxyalkyl group having 3 to 8 carbon atoms, n is an integer of 1 or more, and the number average value is 1 to 10
It is. Acrylate or methacrylate of ε-caprolactone oligomer represented by the following formula: vinyl acetate,
Vinyl esters such as vinyl propionate: styrene, α
-Aromatic vinyl compounds such as methylstyrene: vinyl such as acrylonitrile and methacrylonitrile or vinylidene nitrile compounds: α-olefins such as ethylene and propylene: conjugated dienes such as butadiene and isoprene: dimethyl maleate, diethyl maleate, and maleic acid Dialkyl esters of unsaturated dicarboxylic acids having 1 to 20 carbon atoms in the alkyl group such as di-n-butyl, dimethyl fumarate, diethyl fumarate and di-n-butyl fumarate: dimethoxyethyl maleate, dimethoxyethyl fumarate and the like Dialkoxyalkyl esters of unsaturated carboxylic acids: vinyl ketones such as methyl vinyl ketone and ethyl vinyl ketone. These can be used alone or in combination of two or more. Of these, alkyl esters and alkoxy esters of acrylic acid or methacrylic acid are particularly preferred.

In the composition of the present invention, an acrylic acid or methacrylic acid ester of a cyano group-containing caprolactone oligomer of the component (A) and an epoxy group-containing monomer of the component (B) are essential components. The copolymer (a) in which the content of the acrylic acid or methacrylic acid ester of the cyano group-containing caprolactone oligomer is 60% by weight or less is particularly preferable in practical use.

The quaternary ammonium salt and the quaternary phosphonium salt used in the present invention have the general formula: It is a compound represented by these. Y in the general formula is a nitrogen or phosphorus atom, R ^{5 to} R ⁸ are an alkyl group, an alkoxyalkyl group,
A hydrocarbon group having about 1 to 25 carbon atoms, such as a polyoxyalkylene group, an aryl group, or an alkylaryl group, at least one of which may have an unsaturated bond or be substituted with a hydroxyl group. Further, two or three of R ^{5 to} R ⁸ may form a heterocyclic ring with a nitrogen atom or a phosphorus atom. X ^- is an anion derived from an inorganic or organic acid hydrogen ion is acidic is bound to a halogen or ^{oxygen, Cl -, Br -, I} -, ClO 4
_{^{-, BF 4 -, BH 4}} -, RSO 3 -, HSO 4 -, ROSO 3 -, RCOO -, H 2 P
_{^{O 4 -, ROPO 3 -,}} (RO) 2 PO 2 H - ( wherein R in the formula is C 1
To about 25 alkyl groups, alkylaryl groups, alkoxyalkyl groups, and aryl groups).

As the quaternary ammonium salt, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetramethylammonium p-toluenesulfonate, tetramethylammonium sulfate, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, Tetra n
-Butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium hydrogensulfite, tetra-n-butylammonium perchlorate, tetra-n-butylammonium phosphate, tetra-n-butylammonium acetate, tetra-n-butylammonium borohydride ,
Decyltrimethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, benzyltrimethylammonium chloride, benzyltriethylammonium iodide, benzylhexadecyldimethylammonium chloride, phenyltriethylammonium chloride, benzyldimethylethylammonium chloride,
(2-methoxyethoxyethyl) ammonium chloride, choline chloride, hexadecylpyridinium bromide, 2,4,6-trimethylpyridinium p-toluenesulfonate, 1,8-diazabicyclo (5.4.0) undecene-7-benzylammonium chloride, hexa Decyltrimethylalkylphenoxypoly (ethyleneoxy) ethylammonium phosphate and the like are exemplified.

As quaternary phosphonium salts, benzyltriphenylphosphonium chloride, methyltriphenylphosphonium bromide, methyltriphenylphosphonium sulfate, hexadecyltriphenylphosphonium bromide, ethyltriphenylphosphonium chloride,
Amyl triphenyl phosphonium bromide, tetra n
-Butylphosphonium bromide, tetraphenylphosphonium bromide, trioctylphenylphosphonium dimethyl phosphate, trioctylphenylphosphonium acetate, bromomethyltriphenylphosphonium bromide, allyltriphenylphosphonium bromide and the like.

These quaternary ammonium salts or quaternary phosphonium salts can be used alone or in combination of two or more.

The quaternary ammonium salt or quaternary phosphonium salt is used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the copolymer rubber. If the amount is less than 0.1 part by weight, the vulcanization rate is low and a vulcanizate having satisfactory physical properties cannot be obtained or a long time is required to obtain a vulcanizate having satisfactory physical properties, and 10 parts by weight is required. If it exceeds, the vulcanization rate becomes extremely high, and processing stability and storage stability are impaired.

The vulcanized composition of the present invention is obtained by adding a quaternary ammonium salt or a quaternary phosphonium salt to a copolymer rubber, and a reinforcing material, a filler, a stabilizer, a plasticizer, which are generally known in the rubber industry.
It is prepared by adding a processing aid or the like and mixing with a kneader such as a roll or a Banbury. The obtained composition is formed into a shape according to the purpose, and further vulcanized to obtain a final product. Vulcanization is usually performed at a temperature of 120 ° C. or higher, preferably 150 to 250 ° C. for 1 to 60 minutes. If necessary, post-vulcanization is further performed at a temperature of 150 to 200 ° C. for 1 to 24 hours.

The composition of the present invention has a high vulcanization rate, compared with the case where a vulcanizing agent known as a vulcanizing agent for a conventional epoxy group-containing copolymer rubber such as ammonium benzoate or zinc dimethyldithiocarbamate is used. A vulcanizate having satisfactory mechanical strength and compression set can be obtained with a good short vulcanization time, and the vulcanization time can be greatly reduced.

The vulcanizate obtained from the composition of the present invention has heat aging resistance,
Excellent oil resistance, compression set, and weather resistance.
It can be widely and effectively used for various sealing materials such as O-rings, gaskets and oil seals, various hoses, diaphragms and the like.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples. In the following description, "part" indicates "part by weight" and "%" indicates "% by weight".

A copolymer rubber having the composition shown in Table 1 was prepared by a usual emulsion polymerization method.

(Examples 1-3 and Comparative Examples 1-3) 100 parts of each copolymer rubber shown in Table 2, stearic acid 1
Parts, 50 parts of MAF carbon black, and predetermined amounts of the vulcanizing agents shown in Table 1 were kneaded using an 8-inch open roll to prepare a blend. The Mooney scorch time of the resulting blend was measured according to JIS K-6300. The obtained mixture was press-vulcanized at 170 ° C for 20 minutes, and further vulcanized in an oven at 150 ° C for 4 hours to obtain a vulcanized product. Table 2 shows the results of evaluating various physical properties of the obtained vulcanized product according to JIS K-6301, and FIG. 1 shows the vulcanization curves of the respective compounds. Here, the vulcanization curve was measured at a temperature of 170 ° C. and a vibration angle of 3 ° using a Monsanto rheometer.

(Examples 4 to 7) 100 parts of copolymer rubber A, 1 part of stearic acid, 50 parts of MAF carbon black, and a predetermined amount of a vulcanizing agent described in Table 3 were kneaded using an 8-inch open roll, and then compounded. Was prepared. The Mooney scorch time of the obtained composition is JIS
It was measured according to K-6300. 170 ° C of the resulting blend
And vulcanized at 150 ° C. for 4 hours in an oven to obtain a vulcanized product. Table 3 shows the results of evaluating various physical properties of the obtained vulcanized product according to JIS K-6301.
Shown in

(Examples 8 to 11, Comparative Example 4) 100 parts of each copolymer rubber shown in Table 4, stearic acid 1
Parts, 50 parts of MAF carbon black, and predetermined amounts of the vulcanizing agents shown in Table 1 were kneaded using an 8-inch open roll to prepare a blend. The Mooney scorch time of the resulting blend was measured according to JIS K-6300. The obtained mixture was press-vulcanized at 170 ° C for 20 minutes, and further vulcanized in an oven at 150 ° C for 4 hours to obtain a vulcanized product. Table 4 shows the results of evaluating various physical properties of the obtained vulcanized product according to JIS K-6301.

[Effects of the Invention] As is clear from the above effects, the composition of the present invention comprises:
A vulcanized rubber having a higher vulcanization rate and a shorter vulcanization time than the conventionally known vulcanization using ammonium benzoate as a vulcanizing agent and having satisfactory physical properties.

[Brief description of the drawings]

FIG. 1 shows the vulcanization curves of the compounds of Examples 1 to 3 and Comparative Examples 1 to 3.

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) C08L 33/14 C08K 5 / 19,5 / 50 C08F 220 / 36,20 / 36 C08F 290/06

Claims (1)

(57) [Claims] (1) Expression 1) (Where R ¹ is hydrogen or a methyl group, R ² is a cyano group-substituted alkyl group, n is an integer of 1 or more, and the number average is 1 to 10.) Containing caprolactone oligomer acrylate or methacrylate 0.5-99.
9% by weight, 2) 0.1 to 10% by weight of an epoxy group-containing monomer, and 3) 100 parts by weight of a copolymer rubber having a polymerization composition of 0 to 99.4% by weight of a monomer copolymerizable therewith. A copolymer rubber vulcanizing composition comprising 0.1 to 10 parts by weight of a quaternary ammonium salt or a quaternary phosphonium salt.