JPH02107658A - Vulcanizable acrylic rubber compound - Google Patents

Abstract

PURPOSE:To obtain the title compound providing a cured material having excellent compression set containing active halogen-containing acrylic rubber, trithiocyanuric acid, metallic salt of dithiocarbamic acid and quaternary ammonium salt or phosphonium salt. CONSTITUTION:(A) 100pts.wt. acrylic rubber consisting of 60-99.9wt.% alkyl acrylate monomer, 10-0.1wt.% active halogen-containing monomer (preferably vinyl chloroacetate) and 30-0wt.% copolymerizable monomer is uniformly blended with (B) 0.1-10pts.wt. trithiocyanuric acid, (C) 0.1-10pts.wt. metallic salt of dithiocarbamic acid, (D) 0.01-5pts.wt. quaternary ammonium salt or phosphonium salt (e.g. tetraethyl ammonium) and other additives (e.g. reinforcing agent, filler or antioxidant) to give a vulcanizable rubber compound.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to vulcanizable acrylic rubber formulations. More particularly, it relates to vulcanizable acrylic rubber formulations which give vulcanizates with very good compression set and tensile strength.

[Conventional technology]

Various acrylic rubber vulcanization systems using halogen as crosslinking sites have been known, but each of them has problems that must be solved.

That is, in the case of a vulcanization system involving a combination of polyvalent amines such as hexamethylene diamine carbamate and hexamethylene tetramine and a dibasic arsenite button or metal oxide as an acid acceptor, 2- When chloroethyl vinyl ether is the crosslinking site, the vulcanization rate is slow and the compression set is inferior, whereas when vinyl chloroacetate is the crosslinking site, the vulcanization rate is too fast to be practical.

Furthermore, in the case of a vulcanization system involving a combination of a fatty acid metal soap and sulfur or a sulfur donor, when 2-chloroethyl vinyl ether is the crosslinking site, the vulcanization rate and compression set are still inferior; When vinyl chloroacetate is the crosslinking site, the vulcanization rate is fast, but the compression set is inferior.

Furthermore, vulcanization systems related to combinations of triazine derivatives and metal oxides (Japanese Patent Publication No. 15815/1983 and Japanese Patent Application Laid-Open No. 1983-1989)
1-58451), the acrylic rubber with 2-chloroethyl vinyl ether as the crosslinking site has a slow vulcanization rate and a short Mooney scorch time, making it impractical; Regarding acrylic rubber used as a crosslinking site, on the other hand, the vulcanization rate is too fast to be practical.

In addition to these, a vulcanization system based on a combination of trithiocyanuric acid and a zinc dithiocarbamate derivative is also known (Japanese Patent Publication No. 13215/1983), which is a combination of soap and sulfur that has been previously proposed. Although sulfur systems are suitable for many purposes, they are disadvantageous when it is desired to obtain the best cure state through rapid curing; The vulcanizate is said to have improved storage properties.

However, although the above-mentioned vulcanization system is effective for acrylic rubber with vinyl chloroacetate as the crosslinking site, it still cannot fully meet the recent demands for high-strength materials, omission of secondary vulcanization, and rapid vulcanization. .

[Problems to be Solved by the Invention] The present invention solves these problems seen in the conventionally known trithiocyanuric acid-dithiocarbamic acid salt vulcanization systems, and provides a system that is particularly excellent in compression set and tensile strength. The object of the present invention is to provide a vulcanization system that provides a vulcanizate with a high temperature.

[Means to solve the problem]

The vulcanizable acrylic rubber composition of the present invention that achieves this objective comprises an active halogen-containing acrylic rubber, trithiocyanuric acid, a dithiocarbamate metal salt, and a quaternary salt.
It contains ammonium salt or phosphonium salt of grade.

The active halogen-containing acrylic rubber to be vulcanized is about 60-99.9% by weight of an alkyl acrylate monomer, about 10-0.1% by weight of an active halogen-containing monomer, and is copolymerizable with each of these monomers. at least one other monomer about 3
It is an elastomeric copolymer obtained by copolymerizing 0 to 0% by weight.

Examples of the alkyl acrylate monomer include alkyl acrylate, alkoxyalkyl acrylate, alkylthioalkyl acrylate, and dianoalkyl acrylate.

Examples of the active halogen-containing monomer include the following, and vinyl chloroacetate is preferably used.

(1) Vinyl chloroacetate, allyl chloroacetate, etc. (2) Addition reaction products of glycidyl compounds such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ester, and monochloroacetic acid.Other monomers that can be copolymerized include: Acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, vinyl acetic acid, maleic acid, fumaric acid, itaconic acid, cinnamic acid, monomethyl maleate, monoethyl maleate, monobutyl maleate, styrene, α-methylstyrene, halogenated styrene , acrylonitrile, methacryloni-1-lyluacrylamide, methacrylamide, N-methylolacrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, vinyl acetate, vinyl chloride, vinylidene chloride, methyl methacrylate, ethyl methacrylate, cyclohexyl acrylate, benzyl Monovinyl or monovinylidene unsaturated compounds such as acrylate and furfuryl acrylate, as well as divinylbenzene, allyl acrylate, allyl methacrylate, alkylene glycol diacrylate, alkylene glycol dimethacrylate, polyalkylene glycol diacrylate, polyalkylene glycol dimethacrylate, Examples include crosslinkable polyene compounds such as trimethylolpropane triacrylate.

As the dithiocarbamate metal salt, one represented by the following general formula is used, (RR'N-05S+r-TM R: lower alkyl group R': lower alkyl group or phenyl group M: monovalent to tetravalent metal, preferably is zinc dimethyldithiocarbamate.

Zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, etc. are used.

Furthermore, as the quaternary ammonium salt or phosphonium salt, those represented by the following general formula are used: (RIR2R,R4P)'X-(R,R2R3R4N)
+X-R1 to R4: an alkyl group, an alkoxy group, an aryl group, an alkylaryl group, an aralkyl group, or a polyoxyalkylene group having 1 to 25 carbon atoms, or 2 to 3 of these together with P or N are hetero X- which can also form a ring structure: CQ-1Br-1 -1H3O, -1H2PO4
-1RCOO-,RO3O□-1R3O-1ROPO2
Examples of anions such as H-1CO□- include tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, n-dodecyltrimethylammonium bromide, cetyldimethylbenzylammonium chloride, and methylcetylammonium bromide. Benzyl ammonium bromide, cetyldimethylethylammonium bromide, octadecyltrimethylammonium bromide, cetylpyridium chloride, cetylpyridium bromide, cetylpyridium iodide, cetylpyridium sulfate, tetraethylammonium acetate, trimethylbenzylammonium benzoate, trimethylbenzylammonium-P -h luenesulfonate, trimethylbenzylammonium borate, 8-benzyl-
1,8-diazabicyclo[5,4,0coundec-7
-enium chloride, 1,8-diazabicyclo[5,
4,OF-undecene-7-methylammonium methosulfate, 5-benzyl-1,5-diazabicyclo[
4,3,01-5-nonenium chloride, 5-benzyl-1,5-diazabicyclo[4゜3.01-5-nonenium bromide, 5-benzyl-1,5-diazabicyclo[4,3,0] -5-nonenium tetrafluoroborate, 5-benzyl-1,5-diazabicyclo[4,
Quaternary ammonium salts such as 3,01-5-nonenium hexafluorophosphate, or for example tetraphenylphosphonium chloride, 1-riphenylbenzylphosphonium chloride, triphenylbenzylphosphonium bromide, triphenylmethoxymethylphosphonium chloride, triphenylmethyl Carbonylmethylphosphonium chloride Methylphosphonium chloride, trioctylbenzylphosphonium chloride, trioctylmethylphosphonium bromide, trioctylethylphosphonium acetate, trioctylethylphosphonium dimethylphosphate, tetraoctylphosphonium chloride, cetyldimethylbenzylphosphonium chloride and other quaternary phosphonium salts can be mentioned.

The essential components of these vulcanization systems are approximately 0 trithiocyanuric acid per 100 parts by weight of active halogen-containing acrylic rubber.
．． 1 to 10 parts by weight, preferably about 0.3 to 2 parts by weight, about 0.1 to 10 parts by weight, preferably about 0.3 to 2 parts by weight of dithiocarbamate metal salts, and also quaternary ammonium salts or The phosphonium salts are each used in a proportion of about 0.01 to 5 parts by weight, preferably about 0.05 to 2 parts by weight.

These compounding ratios were specified as preferred ranges from the values of various properties and characteristics such as vulcanization rate, storage stability, processing safety, mechanical properties of vulcanizate, heat resistance, and compression set. It is something. If each vulcanizing system component is used in a blending ratio below this, the vulcanization rate will decrease considerably, and the general physical properties of the vulcanizate will not be obtained.On the other hand, if the blending ratio is higher than this, If used, the vulcanization rate will generally increase, but storage stability, processing safety, general physical properties of the vulcanizate, etc. will be impaired, so it is not preferable.

Vulcanization is a process in which these vulcanized components are mixed with other additives such as reinforcing agents, fillers, anti-aging agents, stabilizers, plasticizers, lubricants, etc. by roll mixing, Banbury mixing, solution mixing, etc. This is done by the following method. The vulcanization temperature is usually 150'C or higher, and vulcanization is carried out by press vulcanization, secondary vulcanization, steam vulcanization, etc. at this temperature.

〔Effect of the invention〕

When the vulcanization system according to the present invention is used, the vulcanization rate during vulcanization is good, and the press vulcanizate obtained is particularly excellent in compression set and tensile strength. The secondary vulcanizate is also superior to conventional vulcanization systems in these respects.

〔Example〕

Next, the present invention will be explained with reference to examples.

Examples 1 to 5, Comparative Example Ethyl acrylate 48.5% (weight, same below), n
-25% butyl acrylate, 24% 2-methoxyethyl acrylate and 2.5% vinyl gloroacetate
Active halogen-containing acrylic rubber 10 made of a copolymer of
0 parts (weight, same below), 1 part of stearic acid, FEF
55 parts of carbon black, 2 parts of anti-aging agent (Uniroyal product Norguard 445), 0 trithiocyanuric acid
．． 5 parts and a dithiocarbamic acid metal salt and a quaternary ammonium salt or phosphonium salt shown in the table below, and using an 8-inch open roll,
The mixture was kneaded for about 30 minutes at a temperature of 0'C.

Mooney scorch time (5 point rise time) of the obtained kneaded product, physical properties of the 180"C51o minute press vulcanizate of this mixed material, and 175°C of this press vulcanizate, 4
The physical properties of the time-secondary vulcanizates were measured. The results obtained are shown in the following table.

(Margin below) Written amendment (voluntary) December 2, 1986

Claims (1)

[Claims] 1. A vulcanizable acrylic rubber compound comprising an active halogen-containing acrylic rubber, trithiocyanuric acid, a dithiocarbamic acid metal salt, and a quaternary ammonium salt or phosphonium salt.