Abstract: A process for preparing a solventless pressure sensitive adhesive composition comprising mixing (A) a solid poly-organosilicate resin component with (B) an aliphatically unsaturated polydiorganosiloxane (B-1), a branched polyorganosiloxane (B-2), or a mixture of (B-1) and (B-2), at certain temperatures, followed by cooling. The solventless pressure sensitive adhesive composition prepared by the process has a low viscosity and can be cured to form pressure sensitive adhesives. The pressure sensitive adhesives are suitable for protective film applications.

Abstract: A method for producing an organopolysiloxane having at least one silicon atom-bonded alkoxysilylalkyl group per molecule is provided. The method comprises the following steps: (i) treating an organopolysiloxane having at least one silicon atom-bonded hydrogen atom per molecule with an alkali salt of carboxylic acid; (ii) removing the alkali salt from the organopolysiloxane; and (iii) reacting the organopolysiloxane with an alkenyl group-containing alkoxysilane in the presence of a platinum-based catalyst. The organopolysiloxane is generally obtained by the method without hydrolyzing any alkoxysilylalkyl groups, and is useful as a surface modifier for various types of fillers.