JPH0749514B2 - Rubber mixture with excellent oil resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is excellent in oil resistance, cold resistance, heat resistance, weather resistance, etc.
The present invention relates to an oil resistant rubber composition obtained by mixing an epichlorohydrin rubber and an alkylene sulfide-epihalohydrin copolymer rubber, which are particularly useful under the contact with alcohol-blended gasoline.

(Prior art) Satisfaction of heat resistance, gasoline (oil) resistance, and cold resistance at the same time by improving engines due to emission regulations of passenger cars that came into effect as a result of social demands for improving atmospheric environment in recent years. Many important safety parts using synthetic rubber have been newly adopted and installed in passenger cars. Among existing synthetic rubbers, epichlorohydrin rubber has been widely used as an excellent synthetic rubber having well-balanced properties in various applications such as hoses, gaskets, O-rings and oil seals.

However, in recent years, as part of the development of alternative energy sources for petroleum worldwide, the use of a mixture of gasoline and alcohols such as ethanol and methanol has been studied, and it has already reached the stage of practical application. However, when such an alcohol-blended gasoline is used as a vehicle fuel, it has a great influence on the rubber material, and the conventionally used epichlorohydrin rubber has increased swelling and is difficult to use as an automobile part. Particularly in the case of methanol-blended gasoline, the effect is great and the swelling is remarkably increased. Therefore, when parts made of epichlorohydrin rubber are mounted on a passenger car, there is a risk that the function cannot be maintained for a long time.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide an alcohol-resistant mixed gasoline without sacrificing the heat resistance, gasoline (oil) resistance, cold resistance, and weather resistance possessed by epichlorohydrin rubber. An object is to provide an oil resistant rubber composition having improved properties.

Means for Solving the Problems This object of the present invention is to provide epichlorohydrin rubber 10 to 80% by weight and alkylene sulfide 15 to 70% by mole, epihalohydrin 30 to 85% by mole and unsaturated epoxide 0 to 15% by mole.
A rubber mixture having a composition of 90 to 20% by weight (hereinafter sometimes referred to as a copolymer rubber) having a composition of

The epichlorohydrin rubber used in the present invention is a polymer of epichlorohydrin or a copolymer of epichlorohydrin and other epoxide and / or unsaturated epoxide. Examples of the epoxide include ethylene oxide, propylene oxide, butene oxide, isobutylene oxide, cyclohexene oxide and styrene oxide.

Examples of unsaturated epoxides include epoxide compounds having a carbon-carbon unsaturated double bond such as butadiene monoxide, allyl glycidyl ether, and glycidyl (meth) acrylate.

The alkylene sulfide in the copolymer rubber used in the present invention, epithiofluorohydrin, epithiochlorohydrin, epithiohalohydrin such as epithiobromohydrin or epithioiodohydrin, ethylene sulfide, Propylene sulfide, butene sulfide, isobutylene sulfide, cyclohexene sulfide, styrene sulfide, p-chlorostyrene sulfide, p-chloromethylstyrene sulfide, methyl thioglycidyl ether, ethyl thioglycidyl ether, allyl thioglycidyl ether, phenyl thioglycidyl ether, methyl thioglycidyl thioether. , Allyl thioglycidyl thioether, phenyl thioglycidyl thioether, thioglycidyl (meth) acrylate, γ-thioglycidyl oxy B pills trimethoxysilane and the like. Of these, epithiochlorohydrin, ethylene sulfide, and methylthioglycidyl ether are particularly preferable.

The epihalohydrin in the copolymer rubber is selected from epifluorohydrin, epichlorohydrin, epibromohydrin and epiiodohydrin, preferably epichlorohydrin.

The unsaturated epoxide may be the same as that used in epichlorohydrin gum.

The composition of the copolymer rubber in the present invention has an alkylene sulfide of 15 to 70 mol%, preferably 20 to 50 mol%, epihalohydrin of 30 to 85 mol%, preferably 40 to 80 mol%, and an unsaturated epoxide of 0 to 15 mol%, preferably 0. ~ 10 mol%.
If the alkylene sulfide content is less than 15 mol%, no improvement in oil resistance, cold resistance, or other performance is observed, while if it exceeds 70 mol%, heat resistance or other performance is impaired. The unsaturated epoxide may be contained as necessary, and especially in a copolymer rubber having a low alkylene sulfide content, the introduction of the unsaturated epoxide can improve cold resistance, performance such as swelling in alcohol-mixed sour gasoline. it can.
However, if the unsaturated epoxide exceeds 15 mol%, the balance of performance will be impaired. The copolymer of the present invention may further contain an alkylene oxide such as ethylene oxide or propylene oxide as a copolymerization component in the range of 0 to 50 mol% in the copolymer, if desired.

In the mixing of the epichlorohydrin rubber and the copolymer rubber in the present invention, the proportion of the epichlorohydrin rubber is appropriately determined within the range of 10 to 80% by weight according to the performance required for the rubber molded product. If it exceeds 80% by weight, the resistance to gasoline blended with alcohol deteriorates, and if it is less than 10% by weight, cold resistance becomes a problem.

As the vulcanizing agent for the mixture of the epichlorohydrin rubber and the copolymer rubber of the present invention, since each contains a chlorine atom, a polythiol-based vulcanizing agent and a thiourea-based vulcanizing agent capable of causing a vulcanization reaction through the chlorine atom. A vulcanizing agent can be used, and a sulfur-based vulcanizing agent can also be used in the epichlorohydrin rubber and copolymer rubber in which unsaturated epoxide is copolymerized.

The polythiol-based vulcanizing agent may be a polythiol-based vulcanizing agent usually used for epichlorohydrin rubber,
Di- or trithiol-S-triazine compound (for example, described in JP-B-48-36926), 2,5-dimercapto-1,3,4
A thiadiazole compound (eg US Pat. No. 4,288,576
No.), 2,3-dimercaptopyrazine compound (for example, described in JP-B-58-14468), 2,3-dimercaptoquinoxaline compound (for example, described in JP-B-58-14469),
3,5-dimercapto-1,2,4-triazole compound (for example, described in JP-B-57-46463) and the like can be mentioned.

Examples of the thiourea-based vulcanizing agent include a 2-mercaptoimidazoline (ethylenethiourea) compound and a 2-mercaptopyrimidine compound (both are described, for example, in JP-B-43-5758).

The sulfur-based vulcanizing agent may be a sulfur-based vulcanizing agent that is usually used for diene rubbers, and sulfur and thiuram compounds such as morpholine disulfide and tetramethylthiuram disulfide and sulfur donors such as polymer polysulfides can be used. Can be mentioned.

The amount of the vulcanizing agent used is 0.1 to 5 parts by weight for sulfur and 0.1 to 10 parts by weight for vulcanizing agents other than sulfur per 100 parts by weight of the mixture of epichlorohydrin rubber and copolymer rubber. It is of course possible to use a vulcanizing agent together.

The rubber composition of the present invention comprises a mixture of epichlorohydrin rubber, alkylene sulfide and epihalohydrin, and optionally a rubber obtained by copolymerizing an unsaturated epoxide, and a vulcanizing agent and, if necessary, a vulcanization accelerator, a reinforcing agent, and a filler. , A plasticizer, an antiaging agent, and other conventional rubber compounding agents are mixed and prepared in a conventional mixer such as a roll or Banbury mixer.

A rubber vulcanizate is obtained by heating this rubber composition in a desired mold usually at 100 to 250 ° C.

(Effects of the Invention) The obtained rubber vulcanizates are not only resistant to alcohol (mixing sour) gasoline, but also oil, cold, etc. especially as fuel hoses, seals, gaskets, O-rings, and diaphragms of automobiles. It exhibits a good balance of physical properties such as properties, heat resistance, and weather resistance.

(Example) Hereinafter, the present invention will be described more specifically with reference to Examples. Parts and% in the examples are based on weight unless otherwise specified.

Example 1 An ethylene sulfide-epichlorohydrin copolymer rubber prepared by a known solution polymerization method using an organoaluminum compound-based polymerization catalyst and an epichlorohydrin polymer (ZECLON 1000 manufactured by Nippon Zeon Co., Ltd.) were blended as follows. Mix on the chill roll with other ingredients according to the prescription,
A vulcanized product was prepared by heating for a minute.

Formulation ZECLON 1000 50 Ethylene sulfide-epichlorohydrin copolymer rubber 50
Stearic acid 1 FEF Carbon 35 Lead oxide 5 2-Mercaptoimidazoline 1.2 Nickel dibutyldithiocarbamate 1 Next, the physical properties of the vulcanizates were measured according to JIS K-6301. The results are shown in Table 1.

From the table, it can be seen that the rubber mixture of the present invention gives a vulcanizate having well-balanced properties.

Example 2 An equimolar copolymer of epichlorohydrin and ethylene oxide (Zecron 2000 manufactured by Zeon Corporation) and ethylene sulfide (45 mol%)-epichlorohydrin (55 mol%)
Each of the copolymer rubbers was mixed with other compounding agents according to the compounding recipe of Table 2 on a cooling roll, and the resulting compound was mixed with the third compounding agent.
A mixture was prepared with a cooling roll at the compounding ratio shown in the table.

The physical properties of the vulcanizate obtained in the same manner as in Example 1 are shown in Table 3 below.

Example 3 Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (Zecron manufactured by Nippon Zeon Co., Ltd.)
2101) and ethylene sulfide (29 mol%)-epichlorohydrin (68 mol%)-allyl glycidyl ether (3
(Mol%) of each of the copolymer rubbers was mixed with other compounding agents on a cooling roll in accordance with the formulation shown in Table 4, and the obtained mixture was prepared on the cooling roll at a compounding ratio shown in Table 5.

The physical properties of the vulcanizate obtained in the same manner as in Example 1 are shown in Table 5 below.

Claims (1)

[Claims] 1. Epichlorohydrin rubber 10 to 80% by weight, alkylene sulfide 15 to 70% by mole, epihalohydrin 85
A rubber mixture having excellent oil resistance, which comprises 90 to 20% by weight of a copolymer rubber containing 30 to 30% by mole and an unsaturated epoxide of 0 to 15% by weight.