Patent ID: 6455613
Filing Date: 2002-09-24
Classification: B60C,C08K,C08L

Abstract:
A tire having at least one component of a rubber composition comprised of, based upon 100 parts by weight of elastomer (phr),A. 100 phr of at least one diene hydrocarbon based elastomer; B. about 35 to about 100 phr of particulate reinforcement comprised of about 35 to about 90 phr of a pre-treated branched, fumed amorphous silica and from about 10 to about 65 phr of at least one additional particulate reinforcement selected from carbon black, synthetic amorphous precipitated silica and silica treated carbon black, wherein said fumed silica aggregates prior to pre-treatment contain hydroxyl groups on their surface; and wherein said pre-treated branched fumed silica aggregates are prepared by (1) pre-treatment with an alkylsilane hydrophobating agent of the general formula (II) and thereafter blended with said elastomer(s) and a silica coupling agent of the general formula (I) namely: [Xm(R2O)3âˆ’mSiâ€”R3]2Szâ€ƒâ€ƒ(I) â€ƒwherein X is chlorine; R2 is selected from methyl and ethyl groups; R3 is an alkylene radical having from 2 through 4 carbon atoms; m is zero or an integer of 1 or 2; and z is an integer of from 2 to 8 with an average of from 2 to about 2.6 or from about 3.5 to about 4, and Xnâ€”Siâ€”R4âˆ’nâ€ƒâ€ƒ(II) â€ƒwherein R is an alkyl radical having from 1 through 4 carbon atoms; n is an integer of from 1 through 3; X is a radical selected from the group consisting of chlorine, and alkoxy radicals selected from methyl and ethyl radicals; or (2) pretreatment with at least one material prior to blending with said elastomer(s) selected from at least one of, or mixtures thereof, of a. hexamethyldisilazane; or b. an organosulfur silane of said general formula (I), or c. an organosulfur silane of the general formula (III) (X)m(R2O)3âˆ’mSiâ€”R3â€”SHâ€ƒâ€ƒ(III) â€ƒwherein X is a chlorine radical; R2 is selected from methyl and ethyl radicals; R3 is an alkylene radical having from 2 through 4 carbon atoms; m is zero or an integer of 1 or 2, and z is an integer of from 2 to 8 with an average of from 2 to about 2.6 or from about 3.5 to about 4; and optionally in addition to the above materials, and optionally d. an alkylsilane hydrophobating agent selected from said general formula (II); â€ƒwherein, said branched fumed silica aggregates are comprised of a primary trunk composed of fused primary silica particles having an average length to diameter (L/D) in a range of about 1.1/1 to about 4/1 and having a multiplicity of branches composed of primary fused silica particles with an average length to diameter (L/D) in a range of about 1.1/1 to about 4/1.