Patent ID: 6534584
Filing Date: 2003-03-18
Classification: B60C,C08K

Abstract:
A rubber composition which comprises(A) 100 parts by weight of at least one diene-based elastomer, (B) about 25 to about 100 phr of particulate reinforcing filler, exclusive of silica treated carbon black, comprised of about zero to about 100 phr of synthetic amorphous precipitated silica aggregates and, correspondingly, from zero to about 75 phr of carbon black, wherein said silica aggregates contain hydroxyl groups on their surface; and (C) about 0.5 to about 10 phr of a coupling agent of 1 -thioglycerol(3-mercapto-1,2-propanediol) as a composite thereof with carbon black, exclusive of 2,2â€²-benzothiazyl disulfide, in a weight ratio of said thioglycerol material to said carbon black in a range of from about 1:10 to about 1:1; wherein said 1-thioglycerol(3-mercapto-1,2-propanediol)/carbon black composite is mixed with said elastomer(s), according to one or more of the following: (1) mixing said 1-thioglycerol(3-mercapto-1,2-propanediol)/carbon black composite with said elastomers and said particulate reinforcing filler; (2) mixing said 1-thioglycerol(3-mercapto-1,2-propanediol)/carbon black composite with said elastomer(s) and said particulate reinforcement filler in an internal rubber mixer, wherein said particulate reinforcement filler includes said synthetic precipitated silica aggregates which have been pre-hydrophobated prior to mixing with said elastomers with an alkylsilane of the general formula (II): Xnâ€”Siâ€”R4-nâ€ƒâ€ƒ(II) wherein X is a radical selected from alkoxy radicals having from 1 though 3 carbon atoms, preferably selected from methoxy and ethoxy radicals, and from halogen radicals selected from at least one of chlorine and bromine radicals, preferably a chlorine radical; R is an alkyl radical having from 1 to 18 carbon atoms, preferably from 1 though 4 carbon atoms and more preferably selected from methyl and ethyl groups; and n is an integer of 1 though 3, (3) mixing said 1-thioglycerol(3-mercapto-1,2-propanediol)/carbon black composite with said elastomer(s), an alkylsilane of the said formula (II) and particulate reinforcement in an internal rubber mixer.