| 摘要 |
<p>A method is provided for bonding a room temperature vulcanizable organopolysiloxane composition to a porous non-metallic, i.e., masonry, substrate in which the bonded composite will be in contact with water. The method comprises: applying, to the masonry substrate, a solution consisting essentially of a product obtained from the reaction of an acrylate and an acryloxyalkylalkoxysilane in the presence of a free radical initiator and an organic solvent; evaporating off the solvent and thereafter applying a room temperature vulcanizable modified organopolysiloxane composition to the dried substrate. The room temperature vulcanizably modified organopolysiloxane composition is obtained from the polymerization of an organopolysiloxane of the formula in which R"" is selected from the class consisting of monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals having from 1 to 18 carbon atoms and a cyanoalkyl radical and x is a number of from 0 to 20,000, with a polymerizable organic monomer having aliphatic unsaturation in the presence of a free radical initiator, and thereafter adding a cross-linking agent to the modified organopolysiloxane. As an important part of such method, compositions are provided that may be used as primers for bonding silicone elastomers to porous non-metallic substrates. These primers exhibit good adhesive properties when applied to porous nonmetallic substrates which are subject to high humidity or where they are in direct contact with water.</p> |
