Solid organopolysiloxanes prodn - by heat treatment of prepolymer film

摘要

Method for reproducibly preparing a solvent soluble further curable partial condensation product organopolysiloxane precured polymer prepd. by reaction of (1) methyl-, ethyl- or phenyltrialkoxysilane or mixtures thereof, in which the alkoxy group has 1-6C, (2) 1.5 moles of water per mole of total silane present and (3) at least a trace of acid, at 50-160 degrees C for 1-10 hrs., comprises (A) forming a liquid film; 1/2-15 mils thick, of the prepolymer having a viscosity equiv. to that of 30-310 cP at 60% solids at 25 degrees C in ethanol, and (B) heating the film at 90-180 degrees C to obtain a solvent soluble precured polymer free from gel. Product may be converted to tack-free flakes or powder e.g. by spray drying, or may be used in liquid form to prepare flexible coatings.