Patent ID: 7473728

Claim:
A dual phase, non-black colored rubber composition comprised of a blend of a first elastomer phase and a second elastomer phase; wherein said dual phase rubber composition is comprised of, based on parts by weight per 100 parts by weight rubber (phr): (A) 100 phr of elastomers comprised of: (1) about 40 to about 90 phr of a butyl-type rubber comprised of at least one of: (a) butyl rubber comprised of a copolymer of isobutylene and about 0.5 to about 3 mole percent of conjugated diene comprised of isoprene, (b) halogenated butyl rubber selected from chlorobutyl and bromobutyl rubber, (c) brominated copolymer of isobutylene and para-methylstyrene, (2) from zero to about 30 phr of EPDM rubber, and (3) about 5 to about 50 phr of natural cis 1,4-polyisoprene rubber, (B) about 5 to about 30 phr of precipitated silica reinforcing filler; (C) partially exfoliated intercalated clay platelets in an amount of from about 5 to about 25 weight percent of a dispersion thereof in said natural cis 1,4-polyisoprene rubber, and (D) a non-black colored pigment colorant; wherein said first elastomer phase is comprised of a pre-blend of said butyl-type rubber(s), said optional EPDM rubber and said precipitated silica; wherein said second elastomer phase is a nanocomposite comprised of a pre-blend of said natural cis 1,4-polyisoprene rubber and said partially exfoliated intercalated clay platelets.