RIGID FOAMS

摘要

E 34337 "Rigid Foams" A method for the preparation of rigid foams comprising reacting a polymethylene polyphenyl polyisocyanate composition with a polyfunctional active hydrogen compound under foam-forming conditions, the polyisocyanate composition containing not more than 20% by weight of diisocyanates and not more than 20% by weight of polyisocyanates containing more than 5 isocyanate groups per molecule. The foams produced have improved fire properties and enhanced surface properties.