Rubber composition and pneumatic tire using same

A tire sidewall comprising:

• a vulcanized rubber component including 25 to 65 weight percent natural rubber;
• a non-ionic surfactant represented by the formula
• where R1 is a monovalent organic group having a carbon number of from 11 to 14 or 15 to 24, with the proviso that where R1 has a carbon number of 15 to 24, the sidewall further comprises a phenolic resin, where each R2 is independently hydrogen or a group that may be represented by the formula C(O)R1, and where m, n, and p are independently an integer from 1 to about 10;
• and
• between about 1 and about 6 pbw phr of an antiozonant.

A method for preparing a tire, the method comprising the steps of:

• mixing ingredients including at least one rubber component, a filler, optionally a non-ionic surfactant, and optionally a phenolic resin, to form a first mixture, where the rubber component includes 25 to 65 weight percent natural rubber;
• cooling the first mixture;
• further mixing the first mixture, optionally with additional ingredients including a non-ionic surfactant and optionally a phenolic resin, to form an intermediate mixture, with the proviso that at least one of the ingredients mixed to form the first mixture or the additional ingredients added to form the intermediate composition includes a non-ionic surfactant represented by the formula
• where R1 is an alkyl group or an alkenyl group having a carbon number of from 11 to 14, where each R2 is independently hydrogen or a group that may be represented by the formula C(O)R1, and where m, n, and p are independently an integer from 1 to about 10;
• adding ingredients including a curative to the intermediate mixture to form a vulcanizable mixture;
• mixing the vulcanizable mixture;
• forming the vulcanizable mixture into a tire sidewall component;
• building a tire by including the tire component;
• and
• curing the tire.