Abstract: 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.

Abstract: A rubber composition for a tire tread includes an organosiloxane-modified diene polymer or a blend of the organosiloxane-modified diene polymer with another diene polymer and a silica or a mixture of the silica and carbon black, the organosiloxane-modified diene polymer being obtained by (a) polymerizing a diene monomer alone or a mixture of the diene monomer and aromatic vinyl monomer by the use of an alkali metal-containing polymerization initiator in a hydrocarbon solvent to give a diene polymer having an alkali metal-containing active end, and (b) reacting the alkali metal-containing active end of the diene polymer with an organosiloxane having at least one functional group selected from epoxy, alkoxyl, carbonyl, vinyl, chloro, bromo and iodo groups. The rubber composition for a tire tread is superior in processability and has both low rolling resistance and high wet-skid resistance by employing a decreased amount of a silane coupling agent.

Abstract: 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:100 parts by weight of a solution polymerized diene rubber;about 5 to about 100 parts by weight of silica;about 1 to about 15 parts by weight of a silane coupling agent; andabout 1 to about 15 parts by weight of a polyalkylene glycol having a weight average molecular weight of about 200 to about 20,000.The invention also provides a method for making the rubber composition, a tire tread made from the rubber composition, and a tire made from the rubber composition.

Abstract: 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.

Abstract: 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.

Abstract: 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:VO(OR).sub.m X.sub.3-mwherein R represents a hydrocarbon group; X represents a halogen atom; and m represents a real number of from 0 to 3, and (b) a dihydroxy hydrocarbon compound constituted of a straight chain hydrocarbon skeleton containing from 2 to 12 carbon atoms and having a hydroxyl group at each of both terminals thereof and at least one hydrocarbon branch bonded to said hydrocarbon skeleton in an inert hydrocarbon solvent at an (a) to (b) molar ratio of from 1:0.5 to 1:1.4 and (B) at least one organoaluminum compound represented by formula:R'.sub.n AlX'.sub.3-nwherein R' represents a hydrocarbon group; X' represents a halogen atom; and n represents a real number more than 0 and less than 3.

Abstract: 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:VO(OR).sub.m X.sub.3-mwherein R represents a hydrocarbon group; X represents a halogen atom; and m represents a real number of from 0 to 3, and (b) a dihydroxy hydrocarbon compound constituted of a straight chain hydrocarbon skeleton containing from 2 to 12 carbon atoms and having a hydroxyl group at each of both terminals thereof and at least one hydrocarbon branch bonded to said hydrocarbon skeleton in an inert hydrocarbon solvent at an (a) to (b) molar ratio of from 1:0.5 to 1:1.4 and (B) at least one organoaluminum compound represented by formula:R'.sub.n AlX'.sub.3-nwherein R' represents a hydrocarbon group X' represents a halogen atom; and n represents a real number more than 0 and less than 3.