Method for coating porous polyurethane resin

Abstract

A method for coating a porous polyurethane resin substrate with an aromatic isocyanate coating composition is provided comprising the steps of (i) providing a porous substrate of a polyurethane foam resin comprising at least one surface upon which the aromatic isocyanate coating composition is to be applied; (ii) applying at least one coating of a primary layer to the substrate surface, the primary layer comprising an aqueous solution of a compound that includes at least one —OH reactive group in its non-aqueous, dry state, and capable, upon drying, of forming a self-supporting, continuous film on the substrate surface at room temperature; (iii) optionally subjecting the applied primary layer to forced drying conditions at a temperature below the softening point of the porous polyurethane resin substrate; and (iv) after allowing the primary layer to substantially dry, applying a secondary layer comprising an aromatic isocyanate compound to the primary layer to form a continuous, film-forming coating on the substrate surface, preferably one having the property of being water-impermeable or water-impermeable and water vapor-permeable.

Dependencies are inferred from the claim text.