Abstract: Organopolysiloxane compositions comprising a polyorganosiloxane having olefinic unsaturation, an organohydrogen polysiloxane and a catalyst, exhibit improved adhesion to a number of substrates when it also comprises an organosilane of the general formula R'(RO).sub.2 SiR", wherein R denotes a monovalent hydrocarbon group, R' denotes an aliphatically unsaturated hydrocarbon or hydrocarbonoxy group and R" denotes an epoxy functional group. The organopolysiloxane compositions also exhibit reduced thixotropy over prior art compositions especially when a reinforcing silica filler is also present.

Abstract: Composition comprising the product obtained by mixing (A) a silanol-terminated polydiorganosiloxane; (B) a silicon compound having at least 3 silicon-bonded alkoxy or alkoxyalkoxy groups in the molecule; (C) a metal or organometal salt of a carboxylic acid; (D) a silane having silicon-bonded alkoxy or alkoxyalkoxy groups and a silicon-bonded group, --R'NHR, in which R' is alkylene and R represents H, alkyl or an aliphatic hydrocarbon group containing at least one amino group, and (E) a silane having silicon-bonded alkoxy or alkoxyalkoxy groups and a silicon-bonded group containing an epoxy group.The compositions cure to elastomers having improved adhesion to glass, aluminium and concrete and are suitable for use as sealants for buildings.

Abstract: A composition which is curable in the presence of moisture to an elastomer having improved adhesion to certain substrates, especially concrete. The composition comprises the product obtained by mixing together (A) a polydiorganosiloxane having terminal silanol groups, (B) an alkoxysilane R.sub.a Si(OR').sub.4-a wherein R represents a monovalent hydrocarbon or halogenated hydrocarbon group having 1-6 carbon atoms, R' is a C.sub.1 to C.sub.4 alkyl group and a is 0 or 1, (C) an organic titanium catalyst, (D) a reinforcing or semi-reinforcing filler and (E) a polydiorganosiloxane gum having a plasticity number (ASTM Test D-926) in the range from 100 to 200.The compositions are particularly suitable for use as sealants for building structures.