GB1348945A - Flame resistant polyurethane composite articles - Google Patents

Abstract

1348945 Fireproof polyurethanes with silicate foam coats BAYER AG 17 May 1972 [19 May 1971] 23186/72 Heading B2E A composite article comprises a flameresistant polyurethane foam which has been wholly or partly coated on the surface with a syntactic foam resin comprising (a) 1 to 20 parts by wt. of hollow beads of a copolymer of 92 to 85 wt. % vinyl chloride and 8 to 15 wt. % ethylene and (b) 80 to 99 parts by weight of a silicate containing matrix material. The polyurethane, in the form of a rigid sheet, may be made according to foreign Specifications listed, and those exemplified are those formed from (1), (3) a polypropylene oxide polyether initiated on bisphenol A and tipped with ethylene oxide and biuret polyisocyanate and (2) polypropylene oxide polyether initiated on ancrose and polyphenyl-polymethylene-polyisocyanate (the product of condensing aniline and formaldehyde and then phosgenating). The hollow beads are formed by foaming finely divided polymer, and the silicate containing binder may be added to the beads before or after blowing. Water-glass is the preferred binder although monomeric or polymeric silicic acid with aliphatic or cycloaliphatic alcohols, or hydrated silicic acid may be used. 1 to 50 parts by weight (based on binder) of additives such as pigments, stabilisers, thickeners, lubricants, elasticising agents, or organic polymer emulsions or water soluble adhesives as described in U.K. Patent Specification 1,170,999. The binder is gelled by aging or removal of water by heat or chemically. Aging may be accelerated by masked acids such as azodicabonamides, percarbonates, carbonic acid esters, formates or ammonium carbonate, oxalate or carbamate. Other suitable accelerators are amine hydrochlorides, ammonium salts or organic acids or polycarboxylic acids. A discontinuous or continuous coating of beads-in-binder syntactic foam may be applied by die extrusion, rollers, doctor blades or coating knives. A coat of water-glass or adhesive may be brushed or sprayed onto the polyurethane before the syntactic foam. Both sides of the polyurethane sheet may be coated.