2.68 v.st.v.amerika 702967 with respect to: production of rigid or semirigid polyurethane foams with warmth insulating ends and fire properties

摘要

1,259,168. Fire retardant polyurethane foams. NATIONAL AERONAUTICS & SPACE ADMINISTRATION. 4 Feb., 1969 [5 Feb., 1968], No. 5817/69. Headings C3C and C3R. Semi-rigid or rigid polyurethane foams are rendered fire-retardant by having uniformly dispersed therein a halogenated polymer and an ionizable inorganic salt, the halogenated polymer being capable of splitting off hydrogen halide and the salt being dissociable on heating and charring of the polyurethane. Suitably the foam also contains an encapsulated, halogenated, volatilizable fire suppressant material. The foam is preferably prepared from polymethylenepolyphenylisocyanates and a polyether formed by reaction of propylene oxide with a sugar or sugar derivative e.g. methyl glucoside. The preferred halogenated polymers are polyvinyl chloride and a terpolymer of vinyl chloride, vinyl acetate and maleic anhydride. Potassium fluoborate is the preferred dissociable salt. Fluorohalocarbons are the preferred encapsulants and may be encapsulated by coascervation with gelatine or polyvinyl alcohol. The foam suitably has a non-foamed skin on its outer surfaces.