Abstract: A process and a polymerization mixture for making integral skin polyurethane wherein Component A containing an isocyanate source is combined with Component B containing a polyol source mixture which includes a blowing agent and a polyurethane catalyst. The blowing agent comprises a carbonate source, and optionally water, an alum source and/or an acid source. The mixture is placed in a mold and the mold is closed. The isocyanate source and polyol source react and the carbonate source decomposes to produce carbon dioxide gas to form an integral skin polyurethane in the closed mold.

Abstract: A method of repairing cementitious substrates with polyurethane in which volatile-free polyurethane precursor reactants are sprayed and polymerized on the surfaces of cementitious articles, such as concrete water conduits.

Abstract: A substrate, such as a roofing substrate, is protected by coating it with a low density polyurethane foam which is then coated with an essentially non-porous, dense, elastomeric polyurethane layer. The layer is formed by spraying a volatile-free spray of polyurethane precursor reactants onto the surface of the foam and rapidly reacting the precursors.