Abstract: A method of hydrophobing fillers such as inorganic pigments, metal oxides, metal hydroxides, and silicate minerals, involves contacting a filler with an oxa-silacycloalkane, until hydroxyl functionality on the filler is replaced with carbinol functionality (i.e. .tbd.C--OH). The preferred oxa-silacycloalkane is 2,2,4-trimethyl-1-oxa-2-silacyclopentane.

Abstract: The present invention relates to a peroxide-curable silicone rubber composition which, when cured, exhibits a reduced modulus and improved tear strength relative to prior art systems without sacrificing other desirable properties, such as high tensile strength of the cured rubber or storage stability of the uncured rubber base, said composition comprising:(A) 100 parts by weight of a diorganopolysiloxane gum;(B) 10 to 75 parts by weight a reinforcing filler;(C) a polybutylene oligomer having a number average molecular weight of 200 to less than 900 and having functionality selected from the group consisting of epoxy, alkoxyphenylene, hydroxyl, carboxyl, anhydride and fully saturated; and, optionally,(D) a hydroxy-terminated diorganopolysiloxane having a degree of polymerization of 2 to 50.

Abstract: There is disclosed a method for treating and protecting a substrate, said method comprising coating the surface of said substrate with a composition comprising a blend of(A) a polydimethylsiloxane polymer having a viscosity at 25.degree. C. of 5 to 100,000 cS; and(B) a polyisobutylene oligomer having a number average molecular weight of 200 to 550. The treatment imparts an aesthetically pleasing appearance to the surfaces of plastic, rubber or leather substrates whereby surface gloss is enhanced, but not excessively, as is the case for a comparable all-silicone treating agent.

Abstract: There is disclosed a method for treating and protecting a substrate, said method comprising coating the surface of said substrate with a composition comprising a blend of(A) a polydimethylsiloxane polymer having a viscosity at 25.degree. C. of 5 to 100,000 cS; and(B) a polyisobutylene oligomer having a number average molecular weight of 200 to 550. The treatment imparts an aesthetically pleasing appearance to the surfaces of plastic, rubber or leather substrates whereby surface gloss is enhanced, but not excessively, as is the case for a comparable all-silicone treating agent.

Abstract: A composition is disclosed, said composition comprising(A) a polydimethylsiloxane having a viscosity greater than about 2 cS at 25.degree. C.; and(B) a polyisobutylene oligomer having a number average molecular weight of about 200 to about 3,000 and having at least one end terminated with an epoxy-containing group, the weight ratio of said polydimethylsiloxane (A) to said polyisobutylene (B) being in the range 1:99 to 99:1.

Abstract: An aqueous emulsion composition suitable for treating cellulosic or masonry surfaces to render them water repellent is disclosed, said composition comprising:(i) an alkoxysilane of the formulaR.sub.n Si(OR').sub.4-nwherein R is an alkyl radical, an alkenyl radical, phenyl, chloropropyl or trifluoropropyl, n is 1 or 2 and R' is an alkyl radical having 1 to 6 carbon atoms;(ii) a silane coupling agent of the formulaR".sub.m R'".sub.p Si(OR').sub.4-m-pwherein R" is selected from the group consisting of amino and quaternary ammonium organofunctional groups, R'" is an alkyl radical having 1 to 4 carbon atoms, R' has its previously defined meaning, m is 1 or 2 and p is 0 or 1, with the proviso that m+p is 2 or less and the molar ratio of said alkoxysilane (i) to said silane coupling agent (ii) is 0.5:1 to 3:1; and (iii) a polyisobutylene polymer, and preferred emulsions of the invention further comprising a wax component.

Abstract: An improved reinforcing silica filler can be produced by treating a reinforcing silica, having a surface area of greater than 50 m.sup.2 /g and from 0.5 to 6 parts by weight of adsorbed moisture per 100 parts by eight of silica, with a volatile treating agent comprising a combination of from 0.2 to 10 parts by weight of volatile treating agent of the formula Vi.sub.x Si(OR').sub.4-x and from 0.2 to 15 parts by weight of volatile treating agent of the formula Ph.sub.x Si(OR').sub.4-x, where Vi is vinyl radical and Ph is phenyl radical. The improved reinforcing silica filler can be combined with polydiorganosiloxane and curing means to produce silicone elastomer compositions which can be cured to elastomers which have improved physical properties, such as compression set and heat aging.