METHOD FOR PREPARING A SILICA SUSPENSION IN AN OPTIONALLY CROSSLINKABLE SILICONE MATRIX

摘要

The invention concerns the preparation of a precipitate silica suspension in a silicone oil, said suspension being used for producing crosslinkable products by polyaddition or by polycondensation (RTV elastomers). The problem the invention aims at solving is the search for a compromise between the cost and the rheology and mechanical properties of the final RTV products. The invention provides a solution by providing a method for preparing a precipitate silica suspension treated with hexamethyldisilazane (HMDZ) in a crosslinkable silicone oil. The introduction of HMDZ is carried out in at least two HMDZ fractions. The first fraction corresponds to a proportion not higher than 15 % by dry weight relative to the total HMDZ amount and is first contacted with the precipitate silica and water. The invention also concerns the method for obtaining a silicone elastomer composition from said suspension, and the resulting composition.