Patent ID: 6555609
Filing Date: 2003-04-29
Classification: B60C,C08K

Abstract:
A rubber composition which comprises(A) 100 parts by weight of an elastomer host as at least one diene-based elastomer, (B) about 25 to about 100 phr of particulate reinforcement as reinforcing filler comprised of about zero to about 100 phr of synthetic amorphous precipitated 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 on their surface; and (C) about 0.5 to about 10 phr of a coupling agent as a combination of materials consisting of 1-thioglycerol(3-mercapto-1,2-propanediol) and 2,2â€²-benzothiazyl disulfide in a weight ratio of said thioglycerol material to said disulfide material in a range of from about 1/10 to 10/; â€ƒwherein said 1-thioglycerol(3-mercapto-1,2-propanodiol) is provided with said elastomer(s), according to one or more of the following (1) said 1-thioglycerol(3-mercapto-1,2-propanodiol) is reacted with the surface of said silica aggregates and/or silica treated carbon black in situ within the elastomer host. (2) said 1-thioglycerol(3-mercapto-1,2-propanodiol), together with a hydrophobating agent are reacted with the surface of said silica aggregates and/or silica treated carbon black in situ within the elastomer host, wherein said hydrophobating agent is of the general Formula (1): Xnâ€”Siâ€”R4-nâ€ƒâ€ƒ(I) â€ƒwherein X is a radical selected from methoxy, ethoxy, chlorine or bromine radicals; R is an alkyl radical having from 1 to 18 carbon atoms; and n is an integer of 1 through 3, (3) said 1-thioglycerol(3-mercapto-1,2-propanodiol) is provided as a pre-formed composite, prior to addition to said elastomer, of said silica aggregates and said 1-thioglycerol(3-mercapto-1,2-propanodiol), wherein (a) said pre-formed composite is formed by (i) by reaction of the 1-thioglycerol(3-mercapto-1,2-propanodiol) with said silica aggregates, or (ii) by reaction of the 1-thioglycerol(3-mercapto-1,2-propanodiol) with the formative colloidal silica particles prior or during their aggregation in the silica precipitation process, or (b) said pre-formed composite is reacted with a hydrophobating agent of the said general formula (1) in situ within the elastomer host.