PROCESS FOR PREPARING CURABLE PERFLUOROELASTOMER COMPOSITIONS

摘要

A non-black filled perfluoroelastomer composition comprising a) a perfluoroelastomer, b) 0.1-30 phr colloidal silica filler having an average particle size <100 nm, and c) a curative is made by 1) mixing an aqueous perfluoroelastomer dispersion with a sol of colloidal silica having an average particle size <100 nm, 2) isolating the perfluoroelastomer composition from the aqueous dispersion and 3) mixing the composition with curative. Cured compositions have surprisingly better compression set than do similar compounds containing hydrophilic silica.