Rubber containing matrix-antidegradants
AssigneeThe Goodyear Tire & Rubber Company
InventorsLarry R. Evans, Walter H. Waddell, Frank W. Harris, David A. Benko
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Abstract
There is disclosed the use of matrix-antidegradants in rubber and a process for the production of matrix-antidegradants. More specifically, this invention is directed to microparticles of vulcanized rubber containing high levels of para-phenylenediamine type antiozonants which have a particle diameter of 100 microns or less. The matrix-antidegradant or microparticles prepared according to this invention provide long term protection to rubber articles that are subject to ozone and oxygen attack.
Claims19
A composition comprising a polymer derived from a diene monomer and a polymer/antidegradant matrix;
- wherein the matrix has a particle diameter of 100 microns or less and a partitioning coefficient of greater than 2.
A finely-divided, vulcanized matrix which comprises 30-90% by weight of a polymer selected form butyl rubber, polyisoprene, polybutadiene, styrene-butadiene copolymers, polychloroprene, polynorbornene, nitrile rubbers and blends thereof, 10-70% by weight of an antidegradant selected from the para-phenylenediamines and substituted derivatives;
- 0-80% by weight of carbon black;
- 0-50% by weight of processing oils and waxes;
- and a curative package;
- said finely-divided matrix has a particle size of less than 100 microns and a partitioning coefficient of greater than 2 relative to the rubber stock to be protected.
An improved rubber vulcanizate, said rubber vulcanizate is prepared by the process comprising:
- (A) combining a vulcanizable diene elastomer with a matrix, said matrix and diene elastomer having a partitioning coefficient of at least 2;
- wherein the matrix is prepared by a process comprising:
- (1) combining an antidegradant with a polymer;
- (2) vulcanizing the polymer/antidegradant compound to form a matrix vulcanizate;
- (3) grinding the resulting matrix vulcanizate to a particle diameter of 100 microns or less;
- and
- (B) vulcanizing the diene elastomer/matrix combination.
A process for the preparation of a matrix which comprises:
- (1) combining an antidegradant with a polymer wherein the polymer is selected with respect to the rubber stock to be protected, so that a partitioning coefficient at least 2 is realized;
- (2) vulcanizing the matrix compound;
- (3) grinding the resulting matrix vulcanizate to a particle diameter of 100 microns or less.
Dependencies are inferred from the claim text.