Patent ID: 6458882
Filing Date: 2002-10-01
Classification: B60C,C08K

Abstract:
A rubber composition which comprises a blend of:(A) 100 parts by weight of at least one diene-based elastomer; (B) about 25 to about 100 phr of particulate reinforcing filler comprised of about 25 to about 100 phr of synthetic amorphous silica aggregates and, correspondingly, from zero to about 75 phr of at least one of carbon black and silica treated carbon black having domains of silica on its surface; wherein said silica aggregates and said silica domains on the surface of said treated carbon black contain hydroxyl groups (e.g. silanol groups) on their surface; and (C) a pre-reacted tetrathiodipropionic acid; wherein said pre-reacted tetrathiodipropionic acid is formed by pre-reacting tetrathiodipropionic acid prior to blending with said elastomer(s), according to one or more of the following: (1) reacting tetrathiodipropionic acid with carbon black to form a carbon black composite thereof, (2) reacting tetrathiodipropionic acid with silica treated carbon black which contains domains of silica on its surface, wherein said silica domains contain hydroxyl groups on their surface, to form a silica treated carbon black composite thereof, (3) reacting tetrathiodipropionic acid with (a) a synthetic precipitated silica which contains hydroxyl groups on the surface thereof to form a silica composite thereof, or (b) an aqueous dispersion of colloidal silica particles, which contain hydroxyl groups on the surface thereof to form a silica composite thereof, wherein said pre-reacted tetrathiodipropionic acid prepared according to any of said steps (1), (2) or (3) is optionally blended with said elastomers and particulate reinforcement, wherein said particulate reinforcement includes at least one of said synthetic precipitated silica aggregates and said silica treated carbon black wherein said particulate reinforcement has been pre-hydrophobated prior to mixing with said elastomers with an alkylsilane of the general formula (I): Xnâ€”Siâ€”R4âˆ’nâ€ƒâ€ƒ(I) wherein X is a radical selected from methoxy and ethoxy radicals, or from chlorine and bromine radicals; R is an alkyl radical having from 1 through 4 carbon atoms; and n is an integer of 1 through 3,wherein said pre-reacted tetrathiodipropionic acid prepared according to any of the steps (1), (2) or (3) is blended with said elastomer(s) and an alkylsilane of the said Formula (I) and said particulate reinforcement, or wherein said pre-reacted tetrathiodipropionic acid prepared according to any of the steps (1), (2) or (3) is optionally blended with said alkisilane of Formula (I) with said elastomer(s) and said particulate reinforcement, wherein said alkylsilane of Formula (I) has been pre-reacted with (a) a synthetic precipitated silica having hydroxyl groups on its surface to form a silica composite thereof, or (b) an aqueous dispersion of colloidal silica particles having hydroxyl groups on its2 surface to form a silica composite thereof.