Coating compositions from polyurethanes containing a molecular sieve of the sodium aluminum silicate type

摘要

A substantially solvent-free fast low temperature curing polyurethane coating composition is disclosed as well as a procedure for synthesizing it and a procedure for applying it to a flexible substrate. It has a long shelf-life yet cures in about 1 to 5 minutes at temperatures of between about 80 DEG and 180 DEG C. to give a flexible coating. The composition is a mixture of a polyisocyanate melting at more than about 100 DEG C. and a hydroxyl bearing polyurethane prepolymer based upon branched polyethers, monomeric glycols, and polyamines made with a deficit of polyisocyanate. The composition includes an isocyanate addition catalyst and a sodium aluminum silicate type molecular sieve and may include a polyester polyol as an additive or a reactant in forming the prepolymer.