Patent ID: 6384127
Filing Date: 2002-05-07
Classification: C08K,Y10S

Abstract:
A process of preparing a rubber composition which comprises the steps of:(A) thermomechanically mixing in at least one sequential preparatory, (non-productive) mixing step and to a temperature within a range of about 150Â° C. to about 185Â° C. and in the absence of addition of free sulfur (1) 100 parts by weight of at least one diene-based elastomer selected from conjugated diene homopolymers and copolymers and copolymers of at least one conjugated diene and aromatic vinyl compound, (2) about 30 to about 100 phr of particulate reinforcing filler comprised of (a) about 5 to about 85 weight percent carbon black and, correspondingly, (b) about 15 to about 95 percent of at least one additional reinforcing filler selected from at least one of the group consisting of alumina and silica-based fillers selected from at least one of precipitated silica, aluminosilicate, and modified carbon black containing silicon hydroxide on its surface, and (3) about 0.05 to about 20, alternatively about 0.05 to about 10, parts by weight per part by weight of said alumina and silica-based filler of at least one organosilane disulfide compound of the formula (I): Zâ€”R1â€”Snâ€”R1â€”Z â€ƒâ€ƒ(I) followed by:B) mixing free sulfur and at least one organosilane polysulfide compound of formula (II) therewith in a subsequent (productive) mixing step to a temperature within in a range of about 100Â° C. to about 130Â° C.: Zâ€”R1â€”Smâ€”R1â€”Z â€ƒâ€ƒ(II) wherein n is a number of from 2 to about 6 and the average for n is in a range of from 2 to 2.6; wherein m is a number of from 2 to about 8 and the average for m is in a range of about 3.5 to about 4.5; wherein Z is selected from the group consisting of: wherein R2 may be the same or different radical and is individually selected from the group consisting of alkyl radicals having 1 to 4 carbons and phenyl radical; R3 may be the same or different radical and is individually selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms, phenyl radical, alkoxy groups having 1 to 8 carbon atoms and cycloalkoxy groups with 5 to 8 carbon atoms; and R1 is a radical selected from the group consisting of a substituted or unsubstituted alkyl radicals having a total of 1 to 18 carbon atoms and substituted or unsubstituted aryl radicals having a total of 6 to 12 carbon atoms.