Silica-containing rubber compositions containing specified coupling agents and related methods

A rubber composition comprising:

• (a) 100 phr of at least one conjugated diene-containing polymer,
• (b) about 50 to about 120 phr reinforcing filler comprising silica or silica in combination with carbon black,
• (c) a bi-functional silane coupling agent, and
• (d) an unsaturated, non-sulfur silane coupling agent,
• wherein the ratio of (c) to (d) is from about 5:1 to about 20:1.

A method for preparing a rubber composition comprising

• (a) 100 phr of at least one conjugated diene-containing polymer,
• (b) about 50 to about 120 phr reinforcing filler comprising silica or silica in combination with carbon black,
• (c) a bi-functional silane coupling agent, and
• (d) an unsaturated, non-sulfur silane coupling agent, wherein the ratio of (c) to (d) is from about 5:1 to about 20:1, and
• wherein the method includes at least one non-productive mixing stage and at least one productive mixing stage, and (a)-(d) are added during non-productive mixing.

A method for reducing electrical resistance in a tire or tire tread, comprising the use of a rubber composition comprising:

• (a) 100 phr of at least one conjugated diene-containing polymer,
• (b) about 50 to about 120 phr reinforcing filler comprising silica or silica in combination with carbon black,
• (c) a bi-functional silane coupling agent, and
• (d) an unsaturated, non-sulfur silane coupling agent, wherein the ratio of (c) to (d) is from about 5:1 to about 20:1,
• in the tire or tire tread.