The adhesion to metal surfaces of room temperature vulcanizable silicone rubber curable through condensation of silicon-bonded hydroxyls with silicon-bonded alkoxy radicals or silicon-bonded hydrogen atoms is improved by contacting the metal surface with acetic acid, formic acid, propionic acid, butyric acid, benzoic acid, toluic acid, metal salts thereof and ammonium salts thereof, removing any excess acid or salt from the surface along with any extraneous materials formed during the contacting, drying the surface and thereafter applying the room temperature vulcanizable silicone rubber to the treated surface and allowing it to cure.
Neutral to basic silicone resin abrasion resistant coating compositions can be adherently secured to cast acrylic plastic substrates without a primer if the substrate is provided with a wash coat of glacial acetic acid shortly before being coated with said silicone resin composition.
