JPS61258845A - Rubber composition - Google Patents

Abstract

PURPOSE:A rubber composition, obtained by incorporating chloroprene rubber with a copolymer consisting of an alkenylphenol and amino group-containing polymerizable monomer, etc., and having improved processability, storage stability, tensile strength and flexural fatigue resistance. CONSTITUTION:A rubber composition obtained by incorporating (A) 100pts.wt. chloroprene rubber with (B) 0.5-50pts.wt., preferably 0.5-20pts.wt. phenol-amine copolymer, prepared by copolymerizing an alkenylphenol, e.g. vinylphenol, with an acrylic acid ester, e.g. 2-methylaminoethyl acrylate, and an amino group- containing polymerizable monomer, etc., and having 300-50,000, preferably 350-10,000 number-average molecular weight.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a copolymer (hereinafter referred to as phenol-amino copolymer) containing chloroprene rubber as an essential component of a polymerizable monomer containing an alkenylphenol and an amino group. )
It relates to a rubber composition which has good processability and has excellent tensile strength or bending fatigue resistance.

[Prior art and its problems]

Ethylene thiourea (hereinafter referred to as EU) is widely used for vulcanization of chloroprene rubber, but problems have been pointed out regarding scorch properties and storage stability of the compound. Also,
Hygiene issues have also been pointed out regarding EU, and rubber processing manufacturers are trying to take measures such as using oil-coated EU to prevent EU from scattering, and various vulcanizing agents have been proposed to replace EU. . For example, tetrahydro-
3,5-dimethyl-oxadiazine-4-thioketone is introduced. Although this vulcanizing agent exhibits good vulcanizing properties when used in combination with tetramethylthiuram disulfide, it has the drawback of poor vulcanizate properties, particularly low tensile strength and elongation. Others: 2,2,4,4-tetrahydroxydiphenyl sulfide, organic peroxides, 2-R-4,6-cythio-8-) riazine.

Vulcanizing agents such as N,N-methylenebisethylenethiourea have also been proposed, but none of them have reached the level of replacing EU due to the balance of physical properties and processability of chloroprene rubber.

However, chloroprene rubber is widely used in automobiles, and its usage is rapidly increasing with the development of the automobile industry, and the hygiene issues mentioned above cannot be ignored. A sulfurizing agent or vulcanization accelerator is required.

[Means for solving problems]

As a result of intensive study of the above-mentioned problems, the present inventors found that
The present invention was achieved by finding a solution to this problem by blending an appropriate amount of a phenol-amino copolymer into chloroprene rubber. That is, one of the objects of the present invention is to provide a novel rubber composition made by blending a phenol-amino copolymer with chloroprene rubber, and another object of the present invention is to provide a novel vulcanizing agent or vulcanization accelerator. Another purpose is to provide a phenol-amino copolymer as an agent;
The object of the present invention is to provide a chloroprene rubber composition that can obtain diversified physical properties by using a phenol-amino copolymer and various rubber processing agents in combination.

The rubber used in the present invention is a vulcanizable rubber made of chloroprene rubber and a blended rubber in which chloroprene rubber is blended with one or more types of natural rubber or synthetic rubber, and depending on the purpose of use, recycled rubber or pulverized vulcanized rubber can be used. It is also possible to partially contain.

The phenol-amino copolymer used in the present invention is:

Vinylphenol, n-benylphenol.

Isopropenylphenol, allylphenol.

n-butenylphenol, 2-butenylphenol,
One or more of each isomer of alkenylphenol such as tert-butenylphenol, and 2-methylaminoethyl acrylate, 2-tert-butylaminoethyl acrylate, 2-dimethylaminoethyl acrylate,
2-diethylaminoethyl acrylate, acrylic acid
Acrylic acid esters such as 2-diallylaminopropargyl, 2-methylaminoethyl methacrylate, 2-isopropylaminoethyl methacrylate, 2-tert-butylaminoethyl methacrylate, methacrylic acid-
2-dimethylaminoethyl, 2-diethylaminoethyl methacrylate, 2-dibutylaminoethyl methacrylate, 2-N-ethyl-N-(2-hydroxyethyl)aminoethyl methacrylate, 2-hydroxy-3 methacrylate -dimethylaminopropyl, methacrylic acid-
Methacrylic acid esters such as 3-methyl-7-methylaminooctyl, amino group-containing polymerizable monomers such as acrylamide, methacrylamide, N-methylolmethacrylamide, N-butoxymethylacrylamide, and N-tert-butylmethacrylamide One or more types of monomers and, if necessary, one or more types of known polymerizable monomers are made into a copolymer by known polymerization techniques such as radical polymerization and cationic polymerization. Furthermore, this copolymer can be used after being modified, for example, by introducing a halogen atom such as a bromine atom onto the tuonol nucleus in the copolymer, or by acylating some or all of the phenolic hydroxyl groups. You can also do it.

The known polymerizable monomers used in the present invention include styrene,
Aromatic or heteroaromatic vinyl monomers such as vinyltoluene, vinylxylene, chlorstyrene, fromstyrene, dichlorostyrene 5α-methylstyrene, 2-vinylpyridine, acrylonitrile, methacrylonitrile,
Acrylic acid, methacrylic acid, maleic anhydride, methyl acrylate.

Acrylic esters other than those listed above, such as ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-ethylhexyl acrylate, and methyl methacrylate , ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, glycidyl methacrylate, other methacrylic acid esters, isoprene, phthadiene, chloroprene, 2-chloroethyl vinyl ether , aryl glycidyl ether, monochlorovinyl acetate, etc.

The number average molecular weight of the phenol-amino copolymer produced as described above is 300 to 50,000, more preferably 350 to 10,000. When the number average molecular weight is less than 300, no improvement in mechanical properties such as tensile strength can be obtained, and when it exceeds 5o;ooo, it becomes difficult to obtain a balance in processability and vulcanizate properties.

There is no particular restriction on the polymerization ratio of the alkenylphenol monomer and the amino group-containing polymerizable monomer in the phenol-amino copolymer, but each.

More than 2 its and more than 5% by weight are preferred. If the respective ratios are less than these, the properties of the vulcanized material will be insufficient.

The blending ratio of the phenol-amino copolymer to the chloroprene rubber is 0.5 parts by weight per 100 parts by weight of the above-mentioned rubber.
~50 parts by weight, more preferably.

The amount is 0.5 to 20 parts by weight.

5. The rubber composition of the present invention also includes reinforcing agents commonly used for rubber compounds, 1 such as carbon black, white carbon, magnesium silicate, barium sulfate, various silicas, silicates, 5 various calcium carbonates, clay, zinc white, Inorganic reinforcing agents such as Shiroenka, phenolic resin, and terpene resin.

Organic reinforcing agents such as various reinforcing fibers, and vulcanizing agents.

For example, sulfur-based vulcanizing agents such as sulfur, selenium, sulfur chloride, and tetramethylthiuram disulfide.

P-quinone dioxime derivatives, organic peroxides, polyaminos, polyols, diisocyanate compounds, metal oxides such as magnesium oxide and litharge, vulcanization accelerators,
For example, guanidines such as diphenylguanidine, thiazoles such as dibenzothiazyl disulfide, thiurams, dithiocarbamates, aldehydes such as hexamethylenetetramine, ammonia, aldehyde/amino condensates, or two or more of these. blend,
Vulcanization aid 1 For example, calcium hydroxide, stearic acid,
Naphthenic acids, cottonseed oil fatty acids, linseed oil.

Lead oleate, dibutylammonium oleate.

Jetanolamino, diphenylguanidine phthalate, processing agent 1, such as phthalate ester, naphthenic process oil, plasticizer or softener such as pine tar, binder such as alkyltunol resin or coumaron/indene resin, and fatty acid Dispersants and anti-aging agents such as and their esters.

For example, N-phenyl-1-naphthylamino and 2,6-
Antioxidants such as tert-butyl-4-methylphenol, antiozonants such as P-phenylene diamino, and anti-crack agents such as N-phenyl-2-naphthylamino 1 Blowing agents, or various coloring agents. It may contain additives.

The rubber composition of the present invention can be prepared by adding chloroprene rubber, a phenol/amino copolymer, and various additives as necessary to a temperature of room temperature to 180°C using a known method 1, for example, using a two-roll or Banbury mixer. Melt and mix with
Alternatively, it is prepared by dissolving and mixing using a solvent such as trichloroethylene, butyl acetate, toluene, etc., and then removing the solvent. At this time, the phenol-amino copolymer and various additives may be premixed as appropriate.

The unvulcanized rubber composition thus obtained usually has a
It is vulcanized and molded by known methods such as compression molding, extrusion molding, injection molding, or direct or indirect heat vulcanization using steam at a temperature of .degree. C. or higher.

[Effect]

According to the present invention, by blending a phenol-amino copolymer into chloroprene rubber, the torque during kneading is reduced, the processability is improved, such as the roll wrapping property of the rubber is excellent, or the effect of suppressing scorch property is achieved. It has good storage stability.

On the other hand, after vulcanization, a vulcanized rubber with good tensile strength or bending fatigue resistance and excellent elongation can also be obtained. Also,
It is easily understood that the phenol-amino copolymer has a high molecular weight and is difficult to bleed from the vulcanizate, but it can also solve the hygiene problems of the EU at the same time.

The composition according to the invention can of course be widely applied to conventional chloroprene rubber applications.

This makes it possible to apply it to new applications such as fields that emphasize bending fatigue.

〔Example〕

In the following Examples and Comparative Examples, parts and parts are by weight unless otherwise specified.

Examples 1 to 10 Phenol-amino copolymers having the copolymer compositions shown in Table 1 were prepared. Using these phenol-amino copolymers, a mixture consisting of each compounding composition shown in Table 2 was prepared.
An unvulcanized rubber composition was obtained by kneading with two inch rolls. The vulcanization properties of these compositions were evaluated using a key last meter (J SR type, 160°C). In addition, vulcanized rubber sheets were prepared by vulcanizing these compositions at 160° C. for a predetermined time using a pressure press.

Regarding the test piece made from this sheet, JIS-6
According to 301, tensile strength (Tb), elongation (Eb), 20
0% tensile stress (M200) and hardness (Hs) were measured. Furthermore, an aging test was conducted at 100° C. for 70 hours. The results are shown in Table 2.

In addition, for the compositions of Examples 8 to 10, JIS-6
300, using a rotor L type, test temperature 125℃
I conducted the Mooney Scorch test.

The results are also shown in Table 2.

Comparative Example 1 An unvulcanized rubber composition was prepared in the same manner as in Example 1 using the formulation shown in Table 2, and various tests similar to those in the Example were conducted. The results are also shown in Table 2.

Table 1 Note) IPP: p-impropenylphenol DM: 2-dimethylaminoethyl methacrylate BA Butyl diacrylate Example 11 Chloroprene rubber (WRT) 100 parts, phenol-amino copolymer 03 parts, carbon black (SRF) )
45 parts, stearic acid 0.5 parts, zinc oxide 5 parts, magnesium oxide 4 parts, antioxidant (N,N-diallyl-p-
) 22 diamino) 1 part Oyohi flose oil (Comolex A2) was kneaded with 10 parts using two 6-inch rolls to obtain an unvulcanized rubber composition. A Mooney scorch test was conducted in the same manner as in Example 8. Further, a vulcanized rubber sheet was prepared in the same manner as in Example 1 except that the vulcanization time was changed to 35 minutes, and the physical properties of the vulcanized material were measured. Furthermore, a crack growth test was conducted using a Dematchi medium bending tester. The respective results are shown in Table 3.

Comparative Example 2 An unvulcanized rubber was prepared in the same manner as in Example 11, except that 0.5 part of EU was used in place of phenol-amino copolymer C, and the vulcanization time was 25 minutes. A vulcanized rubber sheet was prepared in the same manner as in Example 11. The results of various tests are also shown in Table 3.

Table 3

Claims (1)

[Claims] A rubber composition characterized by blending chloroprene rubber with a copolymer containing alkenylphenol and a polymerizable monomer containing an amino group as essential components.