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.