Silica reinforced rubber composition and use in tires

Claim 1

A process of preparing a composite of an elastomer composition which contains a silica-containing reinforcement therein comprises the sequential steps of: (A) thermomechanically mixing in at least one preparatory mixing step to a temperature of about 140° C. to about 190° C.°, (i) 100 parts by weight of at least one sulfur-vulcanizable elastomer selected from homopolymers and copolymers of styrene and 1,3-butadiene and copolymers styrene with isoprene and/or 1,3-butadiene, (ii) about 15 to about 100 phr of particulate filler comprised of at least one filler selected from silica-based fillers and silica modified carbon black, wherein said silica-containing filler is selected from at least one of precipitated silica and aluminosilicate and wherein said silica modified carbon black contains silanol groups on it surface and is prepared by reacting carbon black with a siloxane or by co-fuming carbon black and silica; (iii) about 0.05 to about 20 parts by weight per part by weight of said particulate filler of at least one organosilane compound selected from at least one of Formula (I) and (II) their mixtures: wherein n is from 2 to 8 with an averaqge of from 3.5 to 4.5, or an average of from 2 to 4 with an average from 2 to 2.6; wherein R 1 is an alkylene group having a total of 2 to 6 carbon atoms; wherein R 3 is an ethoxy group; and wherein X is selected from mercapto, thiocyanato, amino, vinyl, epoxide, acrylate and methacrylate groups; (iv) subsequently mixing therewith, at said temperature range of about 140° C. to about 190° C., at least one silane condensation reaction promoter and/or inhibitor; to thereby promote a condensation reaction os said organosilane compound of said formula (I) or formula (II) within said sulfur vulcanizable elastomer(s), and wherein said silane condensation promoter and/or inhibitor is selected from at least one of (a) basic promoters selected from ammonia, ammonium hydroxide, N-butylamine, terbutylamine, tetrahydrofuran (THF), sodium fluoride, pentaethylene hexamine, diaminopropane, diethylenetriamine, triethylenetetramine, poly(allylaminehydrochloride), poly(L-lysine hydrobromide), poly(L-arginine hydrochloride) and poly(L-histidine hydrochloride), (b) acidic promoters selected from phosphoric acid, acetic acid, hydrofluoric acid and sulfuric acid, and (c) catalysts selected from bis(2-ethylehxanoate) tin, bis(neodecanoate) tin, and dibutyl tin diacetate, dibutyl tin dilaurate, stannous octoate, stannous acetate, lead naphthanate, cobalt naphthanate and zinc octoate; followed by: (B) subsequently blending sulfur therewith, in a final thermomechanical mixing step at a temperature to about 100° C. to about 120°C.