Pamela L Graham

US Patent:

51910080, Mar 2, 1993

Filed:

Oct 21, 1991

Appl. No.:

7/779666

Inventors:

Howard H. Frost - Calhoun GA
Pamela S. Graham - Stow OH
Ronald D. Fiedler - Atwater OH
Ramesh N. Gujarathi - Akron OH

Assignee:

The Goodyear Tire & Rubber Company - Akron OH

International Classification:

C08F 216

US Classification:

524460

Abstract:

The present invention relates to a free radical emulsion polymerization process. The latex is prepared by polymerizing (a) at least one conjugated diene, (b) at least one non-carboxylic vinyl aromatic or aliphatic comonomer selected from the group consisting of styrene,. alpha. -methyl styrene, p-methyl styrene, vinyl toluene, acrylonitrile, methacrylonitrile, vinylidene chloride, ethyl acrylate, butyl acrylate, vinyl pyridine, methylmethacrylate, hexylacrylate, 2-ethyl hexyl acrylate or mixtures thereof, and (c) at least one ethylenically unsaturated carboxylic acid monomer selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, fumaric acid,. beta. -carboxyethyl acrylate, itaconic acid or mixtures thereof. The process of the present invention is characterized by (1) polymerizing a first portion of non-carboxylic comonomer in the absence of any conjugated diene to a conversion of 60 to 90 percent to form a partially polymerized latex; (2) introducing to the partially polymerized latex the total amount of conjugated diene to be polymerized; (3) copolymerizing the conjugated diene with the unreacted non-carboxylic comonomer in the partially polymerized latex to a conversion of 75 to 90 percent of unreacted conjugated diene and noncarboxylic comonomer; (4) introducing the remaining portion of non-carboxylic comonomer to be polymerized to the latex having a conversion of 75 to 90 percent; and (5) copolymerizing the remaining portion of non-carboxylic comonomer in the latex with the unreacted conjugated diene latex to form a latex having a conversion of from 90 to 100 percent.