Patent GB-1452573-A (GB)
Title: Flexible hot-moulded flame retardant polyurethane foams
IPC: C08G18/00
Filed: 1974-08-29
Abstract: 1452573 Polyurethane foams GENERAL TIRE & RUBBER CO 29 Aug 1974 [8 Nov 1973] 37873/74 Heading C3R A flexible or semi-flexible hot-moulded low density, fire retardant polyurethane foam is prepared by the reaction of (A) a polyetherpolyol having from 2-4 hydroxyl groups and a M.Wt. of from 1000-10,000, (B) an organic polyisocyanate, and generally (C) a blowing agent comprising water in admixture with (D) a surfactant, and generally (E) a catalyst, (F) from 1-50 pbw per 100 pbw of polyol of a finely-divided, solid chlorine-containing polymeric resin containing an average of from 0À4-1 chlorine atom per carbon atom and having an intrinsic viscosity of from 0À25-2À5 as measured in 0À3% wt solution in cyclohexane at 25 C. and preferably having average particles sizes of from 0À00001-1 mm., (G) finely divided zinc oxide, preferably having an average particle size of 0À05-200 microns, in an amount of from 0À1-10 pbw per 100 pbw of polyol, (H) finely divided antimony trioxide, preferably having an average particle size of 0À05-200 microns, in an amount of from 0À5-15 pbw per 100 pbw of polyol, and optionally, (J), a chlorinated paraffin having an average M.Wt. of from 250-1400 and containing 40-70% wt. of chlorine, using the one-shot or prepolymer process, the improvement comprising incorporating in the formulation from 0À05-2À5 pbw per 100 pbw of polyol at least one compound selected from the oxides, hydroxides and basic salts, particularly carbonates, of metals of Group IIa of the Periodic Table of the Elements having atomic numbers of 12-56, said compounds having an average particle size of from 0À05-200 microns, any magnesium oxide used having an activity number of 0-60, there being generally at least 0À05 pbw of said compounds in any premix of components containing at least 10 pbw of polyol (A). Polyol (A) is preferably a polyalkylene ether polyol. Suitable polyisocyanates (B) are toluene diisocyanates; diphenylmethane di-isocyanates and polymers thereof; and diisocyanato methyl benzene. Suitable resins (F) are polyvinyl chloride, a copolymer of a major amount of vinyl chloride and a minor amount of vinyl acetate and a partially hydrolysed product of the copolymer, and chlorinated polyethylene. Foaming agents which may be used in addition to water are halocarbon, alkanes, alkenes and ethers. Preferred catalysts are divalent tin salts of carboxylic acids preferably in admixture with a tertiary amine. Suitable surfactants are silicone, polysiloxanepolyoxyalkylene block copolymers and Turkey red oil. In the examples foams are prepared from (A) a partially primary OH capped polyoxypropylene triol of M.Wt. 3000, (B) a mixture of 2,4- and 2,6-toluene diisocyanate, (C) water alone and together with trichlorofluoromethane; (D) polyoxyalkylene-polysiloxane; (E) triethylene diamine in dipropylene glycol alone and together with dimethylcyclohexylamine; (F) polyvinyl chloride; and zinc oxide, antimony trioxide and either magnesium oxide, or a mixture of magnesium oxide and magnesium carbonate or a mixture of calcium carbonate and magnesium carbonate.