Smoke inhibiting polyisocyanurate foam prepn - from polyisocyanate with added organopolysiloxane polyoxyalkylene copolymer or polyvinyl silane having polyoxyalkylene side chains

摘要

Process for prepg. a smoke-arresting polyisocyanurate foam, by reacting an organic polyisocyanate (I) in the presence of a blowing agent and of an isocyanate-trimerisation catalyst, takes place with addn. of 0.5-6(1-5) esp. 1.5-4wt.% organo-silicon surfactant (calcd. as Si and w.r.t. total components of foam) which contains 4-22(5-18)% Si and consists of an organopolysiloxane-polyoxyalkylene copolymer, a polyvinyl silane with polyoxyalkylene side-chains or a modified prod. thereof, and in which mol.ratio of EO (ethylene oxide units of polyoxyalkylene part of surfactant) to sum of PO (propylene oxide units of polyoxyalkylene part of surfactant) and EO is >=40 (>=50) esp. 100%. Foams generate little smoke, have low friability, high non-inflammability, flame-retarding props., dimensional stability at high temps., e.g. >=200 degrees C, and do not tend to burst on contact with a flame.