Process for heat sealing polyurethane foam

A process for heat sealing flexible polyurethane foam to a substrate comprising:

• A. reacting and foaming a flexible polyurethane foam produced by the steps comprising reacting:
• (I) an organic polyisocyanate;
• (II) a polyol having a molecular weight of 2,000 to 8,000 comprising the adduct obtained by sequentially reacting:
• (a) a polyhydroxyl initiator, with a functionality of 2 to 5 and a weight average molecular weight as determined by gel permeation chromatography of from 50 to 200;
• with
• (b) 10 to 90%, by weight based on the total oxide present in (b)+(c)+(d), a first alkylene oxide;
• and subsequently reacting the product with
• (c) 10 to 80%, by weight, based on the total oxide present in (b)+(c)+(d), 4,4,4-trichloro-1,2-epoxybutane and/or epihalohydrin;
• and subsequently reacting the product with
• (d) 10 to 60%, by weight, based on the total oxide present in (b)+(c)+(d), a second alkylene oxide;
• (III) foaming agent;
• and optionally
• (IV) catalyst;
• B. allowing said resulting polyurethane foam to cure;
• C. heating a portion of the surface of said flexible polyurethane foam of (B) above its melting or fusion point;
• and
• D. contacting the melted or fused surface of said polyurethane flexible foam with a substrate whereby a flexible polyurethane foam/substrate laminate is formed;
• and
• E. cooling said flexible polyurethane foam/substrate laminate below the melting or fusion point of said foam.