PROCESS ADDITIVES FOR SILICA FILLED COMPOUNDS. PROCESSING WITHOUT PROPERTY LOSS(Paper No.17B)

摘要

Precipitated silica has been used as filler in rubber compounds for more than 60 years. The first recorded use was as cheap filler for coloured and white compounds such as shoe soles, mats, floor coverings etc. Despite the fact that precipitated silica is classified as active filler, the level of reinforcement of silica in those applications was poor compared with carbon black. This resulted in high viscosity compounds with low abrasion resistance and made it impossible to use silica in high volume compounds with high performance requirements such as tire treads.This situation was changed by the use of silane chemicals as an adhesive system between the polymers and the silica filler. High reinforcement combined with low abrasion, was achieved. During the last 10 years nearly all major tire companies developed tread compounds using silica as the main filler. Additionally, non-tire applications such as long range conveyor belts, and supporting systems for dynamically loaded parts made extensive use of silica.Though silica filled compounds have been known for many years, some specific processing problems still remain. This paper will describe the nature of those processing problems, and propose a new additive, called Struktol HT 254, as a means to overcome most of the problems, whilst enhancing both uncured and cured compound properties.