Curable, storage-stable liquid organopolysiloxane compositions

A method for the formulation of a curable, storagestable liquid organopolysiloxane composition of matter, which method comprises admixing for at least two hours at a temperature of less than about 60.degree. C. (a) 100 parts by weight of a diorganopolysiloxane oil having a viscosity ranging from between 400 and 3,000 cps at 25.degree. C. wherein the organo radicals comprising the said diorganopolysiloxane are selected from the group consisting of methyl, vinyl and phenyl and are at least 40% methyl, up to 58% phenyl and up to 2% vinyl, said diorganopolysiloxane being terminated at its chain ends with a moiety selected from the group consisting of (CH.sub.3).sub.3 SiO.sub.0.5, (CH.sub.3).sub.2 CH.sub.2 .dbd.CHSiO.sub.0.5 and (CH.sub.3).sub.2 C.sub.6 H.sub.5 SiO.sub.0.5, with (b) 30 to 75 parts by weight of silica having a specific surface area in excess of 80.sup.2 m/g, (c) 1.5 to 7 parts by weight of water, and (d) 4 to 18 parts by weight of a Si-N bonded silylating agent selected from the group consisting of R(CH.sub.3).sub.2 SiNH-Si(CH.sub.3).sub.2 R and R(CH.sub.3).sub.2 SiNHR', wherein each R is either the same or different and is methyl, ethyl, vinyl or phenyl, and R' is methyl or ethyl;

• next devolatilizing the mixture at a temperature of from about 70.degree. C. to 200.degree. C. under a pressure no greater than atmospheric;
• and thence admixing with the devolatilized product, 45 to 120 parts of (e) an .alpha.,.omega.-dihydroxypolysiloxane oil having a viscosity ranging from between 2,000 and 60,000 cps at 25.degree. C. and 25 to 120 parts by weight of (f) a filler which is a silica having a specific surface area of less than 50 m.sup.2 /g.