1441200 Flame-retardant polyurethane foams GENERAL TIRE & RUBBER CO 30 Aug 1974 [26 Dec 1973] 38017/74 Heading C3R A low-density flexible or semi-flexible flameretardant polyetherurethane foam derived from a polyether polyol having a molecular weight of from 1000-10,000 and having from 2-4 hydroxyl groups, contains, based on 100 p.b.w. of said polyol, (1) from 1-50 p.b.w. of a finely divided solid chlorine containing polymeric resin having an intrinsic viscosity of from 0À25- 2-5, (2) 0À1-10 p.b.w. of finely divided zinc oxide, (3) 0À5-15 p.b.w. of finely divided antimony trioxide, and (4) 0À01-0À90 p.b.w., computed as metallic zinc, of a zinc salt of an organic monocarboxylic acid or a zinc salt of an organic monodithiocarbamic acid, the said salt having from 1-25 carbon atoms in each acid moiety of said salt.; The foam can be made by the one shot or prepolymer process by incorporating the said zinc salt in the foam formulation prior to foaming, the formulation additionally comprising an organic polyisocyanate, a surfactant, a catalyst, a blowing agent comprising water, and optionally a chlorinated paraffin having a M.Wt of 250-1400 and containing 40-70% wt. of chlorine. The zinc salts may be represented by the formul and where R and R1 are selected from alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic groups, R having up to 20 carbon atoms and R1 up to 12 carbon atoms. Suitable halogen-containing polymers are those of vinyl chloride and/or vinylidene chloride, various copolymers thereof, hydrolyzed vinyl chloride/vinyl acetate copolymers, chlorinated rubber, chlorinated polyethylene and chlorinated polyvinyl chloride.; Suitable polyetherpolyols are linear and branched polyoxyalkylene polyols many examples of which are listed. The preferred catalyst is a mixture of an organic tertiary amine and a metal containing oc-catalyst. Suitable surfactants are poly-siloxane-polyoxyalkylene copolymers, silicons and Turkey-red oil. The formulation may additionally comprise a crosslinker having 2-8 OH groups and a M.Wt. of 60-600; an additional blowing agent which is a fluoroxarbon and/or an alkane or alkene; clay, talc, TiO 2 , silica, hydrated silica, CaCO 3 , metal chromates, barytes, phthalocyanine pigments, carbon black, epoxidized soybean oil, epoxides, tricresyl phosphate and other conventional additives.; In the examples foams are prepared from a formulation comprising a polyether triol of M.Wt. 3000 which is a propylene oxide adduct of glycerol, a polysiloxane polyoxyalkylene block copolymer, stannous octoate, water, methyl dicyclohexylamine, triethylene diamine, emulsion polymerized polyvinyl chloride (I.V.=1À28), antimony trioxido, zinc oxide (French process) tolylene diisocyanate and any one of the following zinc salts: zinc stearate zinc acetate, zinc caprylate, zincdimethyl dithiocarbamate and zinc diethyl dithiocarbamate.