Abstract: A process for improving the adhesion of aqueous silicone elastomeric materials to porous masonry substrates consists essentially of first coating the substrate with an aqueous silicone emulsion which provides an elastomeric coating upon removal of the water, the emulsion having a viscosity of from 0.1 to 10 Pa.s at 25.degree. C. and a pH of from 7 to 11.5 inclusive. After the first coating is dried to form a film, a second aqueous silicone emulsion which provides an elastomeric material upon removal of the water is applied. The second aqueous silicone emulsion has a solids content of greater than 15 percent by weight and a viscosity of greater than 10 Pa.s at 25.degree. C. The second silicone emulsion is then allowed to dry, forming an elastomer firmly adhered to the substrate. The elastomer can be in the form of a coating to give protection to the substrate from the effects of water, pollution, or sunlight; or can be in the form of a sealant to seal spaces between masonry pieces.

Abstract: When a silicone elastomeric coating is applied over a polyurethane foam to protect it, an adhesion problem arises. It has been found that a coating of from 0.05 to 0.2 grams per square foot of surface of a silane of the formula ZSi (OR).sub.3, where Z is an amine functional radical and R is a monovalent hydrocarbon radical having from 1 to 6 carbon atoms, applied to the polyurethane foam under the silicone elastomeric coating greatly improves the adhesion between them. The silicone elastomeric coating is a particular type of tin catalyzed silicone coating comprising a particular organosilicon resin, a hydroxy-ended silicone polymer, and filler.

Abstract: There is disclosed a room temperature curing silicone for protecting polyurethane foam. The silicone coating provides protection from ultraviolet light, water penetration, and mechanical damage. The silicone coating comprises a particular organosilicon resin, an hydroxy-ended silicone polymer, fillers, and an organotin catalyst.

Abstract: Improved reactive liquid silicone resins are disclosed. The resins are the product of certain reactive liquid resins and a compound selected from acyloxysilanes, alkoxysilanes, and oximosilanes. When incorporated in a curable silicone composition, such as an elastomeric coating, the improved resins of this invention confer improved working time to the curable composition, and enhance the adhesion of the curable composition to a substrate.

Abstract: A silicone elastomer obtained by drying an aqueous silicone elastomeric emulsion containing an anionically stabilized hydroxyl endblocked polydiorganosiloxane, colloidal silica, alkyl tin salt, and clay exhibits weight loss and embrittlement on exposure to elevated temperature. It has been found that the rate of weight loss can be reduced by the addition of greater than 2 parts by weight of finely divided zinc oxide per 100 parts of polydiorganosiloxane by weight to the emulsion.

Abstract: Heat-curable silicone elastomer compositions are disclosed which comprise a low-viscosity polydiorganosiloxane, free of silicon-bonded hydroxy radicals and silicon-bonded hydrolyzable radicals, an organic peroxide, a filler and an alkenyltriacetoxysilane. A process for curing the resulting compositions to provide elastomeric materials having a dry, non-tacky surface is also disclosed. The compositions of this invention also have improved adhesion to certain substrates when heat-cured in contact with the substrate.