JPS5950178B2 - Phenol group-containing acrylic elastomer vulcanized compound - Google Patents

Description

[Detailed description of the invention] The present invention relates to acrylic elastomer vulcanized formulations.

More particularly, it relates to vulcanized formulations of acrylic elastomers containing phenolic groups as crosslinkable groups. Conventionally, a method has been used in which the high reactivity of carboxyl groups is utilized to cause a crosslinking reaction between a carboxyl group-containing elastomer and another elastomer to obtain a mixed elastomer vulcanizate with improved physical properties.

However, vulcanized compounds prepared using polyepoxy compounds, which are common vulcanizing agents for carboxyl group-containing elastomers, often have problems with storage stability due to the high reactivity of carboxyl groups. It was done. The inventor is
As a result of various studies in order to prepare an acrylic elastomer vulcanized compound that has good storage stability and excellent vulcanization properties and vulcanizate physical properties, we have developed an acrylic elastomer containing a phenol group as a crosslinking group and a specific It has been found that vulcanizing formulations containing vulcanizing agents can effectively achieve the above objectives.

Hitherto, no compound has been found that serves as a suitable vulcanizing agent for phenol groups to achieve crosslinkable groups, and therefore phenol group-containing acrylic elastomers themselves have hardly been effectively utilized.

Aldehyde compounds are commonly used as compounds that react with phenol groups, but these compounds have specific irritation and are therefore completely unsuitable for use as rubber vulcanizing agents. However, when polyactive halogen group-containing compounds are used as vulcanizing agents, highly effective phenolic group-containing acrylic elastomer vulcanization formulations are prepared. Accordingly, the present invention relates to a phenolic group-containing acrylic elastomer vulcanization formulation, which vulcanization formulation comprises a phenolic group-containing acrylic elastomer, a polyactive halogen group-containing compound vulcanizing agent, a quaternary ammonium salt or a quaternary phosphonium salt. It contains a sulfur accelerator and a divalent metal oxide or hydroxide vulcanization accelerator.

The phenol group-containing acrylic elastomer contains 50 to 99.9% by weight of acrylic ester, 30 to 0.1% by weight of phenol group-containing monomer, and 20 to 20% of other monomers copolymerizable with these comonomers. Consisting of 0% by weight copolymer.

Examples of acrylic esters include methyl acrylate, ethyl acrylate, n- or iso-propylacrylate, n- or iso-butyl acrylate, 2
- Acrylic acrylate in which the acrylic group has 1 to 8 carbon atoms, such as ethylhexyl acrylate, n-octyl acrylate, methoxymethyl acrylate, 2
Alkoxyalkyl acrylates each having 1 to 4 carbon atoms such as acrylic and alkylene groups such as -methoxyethyl acrylate and 2-ethoxyethyl acrylate are used, with ethyl acrylate being particularly preferred. Examples of the phenol group-containing monomers include o-hydroxystyrene, α-methyl-o-hydroxystyrene, β-methyl-o-hydroxystyrene, o-cabicol, and their m-, p-isomers, p- or m-
Vinyl hydroxybenzoate, vinyl salicylate, eugenol, isoeugenol, p-hydroxybenzoic acid 4
- or 3-vinylbenzyl, etc. are used. The phenol group-containing acrylic elastomer may further be copolymerized with other monomers that can be copolymerized with acrylic acid esters such as styrene, acrylonitrile, and vinyl acetate, and the phenol group-containing monomer. Examples of the polyactive halogen group-containing compound used as a vulcanizing agent include 2,2-bis(4-chloromethylphenyl)propane,
Bis(4-chloromethylphenyl)methane, α, α′-
Dichloro-o-xylylene and its m- or p
- Compounds containing halogenoalkyl groups such as isomers, polyethylene glycol bischloroacetate, xylylene diol bischloroacetate, 2,2-bis(4-chloroacetoxyphenyl)propane, and even 2,2-bis(4-glycidyl) A compound containing a halogenated acyl group, such as an adduct of oxyphenyl)propane or polyethylene glycol diglycidyl ether and chloroacetic acid, is used.

the above-mentioned halogen alkyl group forming an active halogen group;
The halogenated acyl group and the like may be substituted with a plurality of halogen atoms such as chlorine and bromine. These polyactive halogen group-containing compounds are about 0.1 to 20 parts by weight per 100 parts by weight of the phenol group-containing acrylic elastomer.
Used in parts by weight. Quaternary ammonium salts and quaternary phosphonium salts used as vulcanization accelerators are represented by the following general formula: where R1 to R4 are alkyl,
It is a hydrocarbon group having 1 to 18 carbon atoms such as allyl, alkylaryl, and aralkyl group, and X is a conjugate base of an inorganic acid or an organic acid.

Specific examples of quaternary ammonium salts include tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, cetyltrimethylammonium chloride, cetyldimethylbenzylammonium chloride, octadecylpyridinium chloride, octadecylisoquinolinium chloride, and tetraethylammonium. Examples include acetate.

Examples of the quaternary phosphonium salt include tetraphenylphosphonium chloride, triphenylbenzylphosphonium chloride, triethylbenzylphosphonium chloride, tricyclohexylbenzylphosphonium chloride, triphenylbenzylphosphonium bromide, triphenylbenzylphosphonium acetate, and the like. These quaternary ammonium salts or quaternary phosphonium salts are
It is used in a proportion of about 0.1 to 10 parts by weight per 0 parts by weight. The vulcanization system also contains a divalent metal oxide or hydroxide as a vulcanization accelerator.

Specific examples of metal oxides include magnesium oxide, calcium oxide, and zinc oxide, and examples of metal hydroxides include magnesium hydroxide, calcium hydroxide, and zinc hydroxide. These divalent metal oxides or hydroxides are used in the phenol group-containing acrylic elastomer 1.
It is used in a proportion of about 1 to 40 parts by weight per 00 parts by weight.
The vulcanized compound containing the phenol group-containing acrylic elastomer and each of the above-mentioned vulcanizable components contains a filler, which is known as a type of compounding agent for rubber, as in the case of a general acrylic elastomer vulcanized compound. , pigments, porous substances, etc. can be further blended.

Kneading is performed using a kneader such as a roll or a Banbury mixer. The vulcanization of the vulcanized compound is about 150-200
Pre-vulcanization carried out for about 1 to 30 minutes at WAC and about 170 to
This is accomplished by post-vulcanization at 2400C for about 1 to 48 hours. The phenol group-containing acrylic elastomer vulcanized compound according to the present invention has superior storage stability and longer scorch time than the carboxyl group-containing acrylic elastomer vulcanized compound, and furthermore, the vulcanizate has It has favorable physical properties such as high elastic modulus and elongation at break. Therefore, by effectively utilizing these properties, it is possible to use it as a high-pressure sealing material for oil seals, O-rings, U-shaped packings, V-shaped packings, etc., which could not be used with conventional acrylic elastomers. In this case, it is not necessarily necessary to reinforce these parts with metal or fiber. As described above, it can be said that the phenol group-containing acrylic elastomer vulcanized compound according to the present invention has greatly improved effectiveness in terms of applications. Next, the effects of the present invention will be explained with reference to Examples. Synthesis of phenol group-containing acrylic elastomer Ethyl acrylate 90 parts (weight, same below)
, 10 parts of p-hydroxybenzoic acid-4-vinylbenzyl ester, 200 parts of water, 2 parts of sodium dodecyl sulfate, and 2 parts of polyoxyethylene dodecyl ether were sequentially charged into a reaction vessel. After maintaining the liquid temperature at 500C and thoroughly purging with nitrogen, 1 part of ammonium persulfate O and 0.1 part of sodium bisulfite are added to start the polymerization reaction. The temperature of the solution rises as the polymerization reaction progresses, but the temperature is maintained at about 600C and the solution is stirred for about 2 hours to complete the reaction. The obtained latex was poured into a 15% saline solution of 80% C for salting out, and washed with water to obtain an ethyl acrylate-p-hydroxybenzoic acid-4-vinylbenzyl ester copolymer elastomer. Example 1 100 parts of phenol group-containing acrylic elastomer, 50 parts of HAF carbon black, 1 part of stearic acid, 2 parts of 4,4'-bis(4-α,α5-dimethylbenzyl)diphenylamine, 1 part of dodecyldimethylbenzylammonium chloride 1 part, 4.5 parts of bischloroacetoxypolyethylene glycol and 6 parts of calcium hydroxide are kneaded with a roll.

The obtained phenol group-containing acrylic elastomer vulcanized compound was press-cured at 190°C for 15 minutes, and then vulcanized at 150°C.
Post-vulcanization was carried out at C for 24 hours. Example 2 Example 1
In the vulcanization formulation, 5 parts of bischloroacetoxylylene diol was used instead of bischloroacetoxypolyethylene glycol, and the press vulcanization time was 17 minutes.

Example 3 In the vulcanization formulation of Example 1, 2,2 bis[4-(3
-chloroacetoxy-2-hydroxyprobyloxy)
Using 6 parts of phenyl]propane, press vulcanization time was 20
It was set as 1 minute.

Comparative Example In the synthesis of the phenol group-containing acrylic elastomer described above, a copolymerization reaction was carried out using 96 parts of ethyl acrylate and 4 parts of methacrylic acid instead of p-hydroxybenzoic acid-4-vinylbenzyl ester. - A methacrylic acid copolymer elastomer was obtained.

To 100 parts of this carboxyl group-containing acrylic elastomer, 50 parts of HAF carbon black, 1 part of stearic acid, 4,4'-bis(4-α,α7-dimethylbenzyl)
2 parts of diphenylamine, 1 part of dodecyldimethylbenzylammonium chloride, and 12 parts of 2,2-bis(4-glycidyloxyphenyl)propane were added and kneaded with a roll.

The obtained carboxyl group-containing acrylic elastomer vulcanized compound was press-cured at 180°C for 10 minutes, and then
Post-vulcanization was carried out at 01C for 24 hours. Regarding the vulcanized formulations of the above examples and comparative examples, the scorch time (△5: time required to increase by 5 points, △3
5: Time required to increase by 35 points) and JI
The physical properties of the vulcanizate were measured according to the test method of SK-6301. The results obtained are shown in the following table. The rheometer cure curves for each vulcanization formulation are also shown in the drawings.

[Brief explanation of the drawing]

The figure is a graph showing rheometer cure curves for the vulcanization formulations of each example and comparative example.

Claims (1)

[Claims] 1 Contains a phenol group-containing acrylic elastomer, a polyactive halogen group-containing compound vulcanizing agent, a quaternary ammonium salt or quaternary phosphonium salt vulcanization accelerator, and a divalent metal oxide or hydroxide vulcanization accelerator. A phenolic group-containing acrylic elastomer vulcanized compound.