Larry Roger Dailey

US Patent:

6393655, May 28, 2002

Filed:

Feb 22, 1999

Appl. No.:

09/255068

Inventors:

Larry Roger Dailey - Uniontown OH

Assignee:

The Goodyear Tire Rubber Company - Akron OH

International Classification:

B60S 102

US Classification:

1525048, 524458, 524836, 526 65

Abstract:

This invention is based upon the unexpected discovery that the physical properties of rubber products made with styrene-butadiene rubber can be significantly improved by synthesizing the styrene-butadiene rubber by a process which comprises (1) charging water, a soap system, a free radical generator, 1,3-butadiene monomer and styrene monomer into a first polymerization zone; (2) allowing the 1,3-butadiene monomer and the styrene monomer to copolymerize in the first polymerization zone to a monomer conversion which is within the range of about 15 percent to about 40 percent to produce a low conversion polymerization medium; (3) charging the low conversion polymerization medium into a second polymerization zone; (4) charging an additional quantity of 1,3-butadiene monomer and an additional quantity of styrene monomer into the second polymerization zone; (5) allowing the copolymerization to continue until a monomer conversion of at least about 50 percent is attained to produce the latex of styrene-butadiene rubber; and (6) recovering the styrene-butadiene rubber from the latex. For example, improved abrasion resistance, compression set and tensile strength can be attained. These improved physical properties offer advantages in a wide variety of rubber products, such as windshield wiper blades, brake diaphragms, washers, seals, gaskets, tires, hoses, conveyor belts, power transmission belts, shoe soles, shoe foxing and floor mats for buildings or automotive applications.