Silica containing rubber composition

Abstract

This invention discloses a method for preparing rubber compositions that exhibit unique combinations of properties that are desirable for tire tread applications for enhanced snow/ice and wet traction, low rolling resistance and increased treadwear performance in comparison with conventional silica compounds. Specifically, a high reactively silane coupling agent, such as a mercaptosilane, is used in combination with a silane coupling typically used for silica tread compounds such as bis(triethoxylsilylpropyl)disulfide to treat silica pellets in a hydrocarbon solvent at elevated temperatures. The treated silica is then blended with solution elastomer cement in a hydrocarbon solvent. The deposited reactive silanes partially react with the elastomer molecules forming a layer of polymer grafted on the silica surfaced. This structure significantly improves the silica retention during the steam stripping operation. Almost 100% (99+%) silica retention has been achieved by this invention. After solvent removal from steam stripping, the treated silica/elastomer mixer is dewatered and dried using conventional equipment such as shaker screens, expellers and expanders to form a well-dispersed silica masterbatch. This technique results in silica compounds with excellent silica dispersion and increased filler-polymer interaction, hence enhanced compound performance such as better physical properties, more desirable dynamic properties (low hysteresis at high temperatures and high hysteresis at low temperatures) and increased abrasion resistance.