Sumitomo Chemical Company, Limited

Hayato Saba

Keisaku Yamamoto

Kizuku Wakatsuki

Kiyoyuki Sugimori

Akio Imai

Katsunari Inagaki

Tadaaki Nishiyama

A rubber composition obtained by kneading a mixture comprising 100 parts by weight of a solution polymerized diene rubber, 5-100 parts by weight of silica, 1-15 parts by weight of a silane coupling agent, and 1-20 parts by weight of an organic silicon compound having a number average molecular weight of about 100-10,000, and maintaining the temperature during the kneading at 200.degree. C. or less. The composition is excellent in wear resistance and productivity, has lower rolling resistance and is useful, for example, for automobile tires.

Rubber composition

Provided is a rubber composition obtainable by kneading a mixture at a maximum temperature between about 120.degree. to about 170.degree. C. The mixture includes:

A process for producing ethylene-.alpha.-olefin copolymer rubbers which comprises mixing a vanadium compound-containing solution and an alcohol-containing solution with stirring for 10-600 seconds to obtain a mixed solution, immediately feeding the mixed solution into a polymerization vessel containing an organoaluminum compound, and copolymerizing ethylene and an .alpha.-olefin, or ethylene, an .alpha.-olefin and a non-conjugated diene compound in the polymerization vessel. According to this process, the activity of polymerization catalyst can be maintained at a high level, no by-product of the reaction of the vanadium compound and the alcohol is deposited as precipitate in the apparatus and no such additional operations as bubbling is necessary.

Process for producing ethylene-alpha-olefin copolymer rubber

A method for purifying an ethylene-.alpha.-olefin olefin having at least 3 carbon atoms, or ethylene with an .alpha.-olefin having at least 3 carbon atoms and a nonconjugated diene compound, in a hydrocarbon solvent in the presence of a catalyst comprising a vanadium compound, an organoaluminum compound, and a halogenated ester compound, the method including a step of mixing and stirring the polymerization reaction mixture obtained by the polymerization reaction in an aqueous alkaline solution in such an amount as to give an aqueous phase having a pH of not lower than 10.0 after mixing and stirring, is disclosed. A method for purifying an ethylene-.alpha.-olefin copolymer is also disclosed, including a step of an oxidation treatment of the polymerization reaction mixture in an aqueous alkaline solution in such an amount as to give an aqueous phase having a pH of not lower than 10.0 after the oxidation treatment.

Method for purifying ethylene-.alpha.-olefin copolymer

An inert hydrocarbon solvent-soluble catalyst for polymerization of olefinic hydrocarbons and a process for producing an olefinic polymer using the same are disclosed, the catalyst being composed of (A) a reaction product obtained by reacting (a) at least one vanadium compound represented by formula:

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Chiba, Japan

Hayato Saba