Patent ID: 8501837

Claim:
A method of preparing a rubber composition containing at least one diene-based elastomer, aramid short fibers and epoxidized cis 1,4-polyisoprene rubber where said method is comprised of, based on parts by weight per 100 parts by weight rubber (phr): (A) preparing a pre-formed masterbatch comprised of a dispersion of aramid short fibers in an epoxidized natural cis 1,4-polyisoprene rubber having an epoxidation in a range of from about 5 to about 60 percent, followed by (B) blending a sufficient amount of said pre-formed masterbatch with another rubber composition comprised of at least one diene-based elastomer other than said epoxidized natural cis 1,4-polyisoprene rubber to provide a rubber composition comprised of, based on parts by weight per 100 parts by weight elastomers (phr): (1) 100 phr of diene-based elastomers comprised of: (a) about 10 to about 95 phr of at elastomers, other than epoxidized natural cis 1,4-polyisoprene rubber, comprised of at least one of polymers and copolymers of isoprene and 1,3-butadiene and copolymers of styrene with at least one of isoprene and 1,3-butadiene as non-functionalized elastomers, and (b) about 5 to about 100 phr of epoxidized natural cis 1,4-polyisoprene rubber, and (2) about 30 to about 100 phr of particulate reinforcement consisting of (a) rubber reinforcing carbon black, or (b) synthetic amorphous precipitated silica, or (c) combination of rubber reinforcing carbon black and synthetic amorphous precipitated silica containing up to about 80 phr of said precipitated silica together with a silica coupler for said precipitated silica; and (3) about 0.5 to about 30 phr of said short aramid fibers.