The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 22, 1997
Filed:
Jul. 21, 1995
Adel F Halasa, Bath, OH (US);
Laurie E Austin, Hartville, OH (US);
Susan A Weakland, Akron, OH (US);
The Goodyear Tire & Rubber Company, Akron, OH (US);
Abstract
The subject invention relates to an anionic polymerization technique for synthesizing rubbery polymers of conjugated diolefin monomers, such as a rubbery copolymer of .alpha.-methylstyrene and 1,3-butadiene. These rubbery copolymers exhibit an excellent combination of properties for utilization in tire tread rubber compounds. They have high trans-isomer contents which leads to good treadwear characteristics and a broad molecular weight distribution which enhances processability. This invention more specifically discloses a process for the synthesis of rubbery polymers which have a broad molecular weight distribution and which are particularly useful in tire tread rubber compounds, said process comprising the polymerization of at least one conjugated diolefin monomer in an organic solvent in the presence of a catalyst system which is comprised of (a) a dialkyl magnesium compound and (b) an alkali metal containing compound selected from the group consisting of alkali metal alkoxides, alkali metal phenoxides, alkali metal sulfoxides, alkali metal sulfonates, alkali metal carboxylates, alkyl substituted alkali metal phenoxides, alkali metal alkylamines, and alkali metal dialkylamines; wherein the molar ratio of the alkali metal containing compound to the dialkyl magnesium compound is within the range of about 6:1 to about 1:5. In cases where rubbery copolymers containing .alpha.-methylstyrene are being synthesized, the alkali metal in the alkali metal containing compound will normally be potassium, rubidium, or cesium, with cesium being most preferred.