Patent GB-1517720-A (GB)
Title: Cellular polyurethane
IPC: C08G18/66
Filed: 1975-09-09
Abstract: 1517720 Cellular polyurethane WITCO CHEMICAL CORP 9 Sept 1975 [12 Nov 1974] 37083/75 Heading C3R A rigid cellular polyurethane product is prepared by curing a lead-free composition suitable for spraying, said composition comprising (a) a polyol containing at least one C2 to C8 carbon chain having a terminal hydroxy group, or an aralkyl or alkaryl polyol, there being 3 to 8 hydroxyl groups per polyol molecule which are each independently alkoxylated by from 0 to 3 C2 to C4 alkoxy units, (b) sufficient of an organic polysiocyanate having at least one aromatic moiety per NCO group to provide an NCO index of from 90 to 150, (c) 0À25 to 10% wt. of an oxyalkylene primary amine of the formula where x is 1 to 8, y is 1 to 4, and R is a y-valent branched or linear saturated carbohydryl radical of 2 to 8 carbon atoms, R<2> is a branched or linear divalent C2-C8 carbohydryl radical and R<1> is a branched or linear C2-C4-alkylene radical, (d) a foaming agent comprising from 0À05-2À5% wt. of water and from 3À5-25% wt. of a blowing agent, the percentages being based on the total weight of the composition, (e) a cellular polyurethane catalyst containing a tertiary amine and a tin compound, and (f) a minor amount of a surfactant cell-size regulator, the (a) and (b) components being the major components, and optionally a fire-retardant. Two-component packs for the production of the cellular polyurethane are described. Suitable polyols (a) are sorbitol, triethanolamine, pentaerythritol, sucrose, glycerine, hexane triol, heptane triol, octane triol, hexane tetrol, octane heptol, trihexanolamine, trimethylolpropane, alpha-methyl glucoside, phenol-HCHO condensates and Mannich condensates of phenol, HCHO and alkanolamines. Preferred components (c) are polyoxy-isopropylamines such as where x = 2-6 (Formula (i)), or wherein the total combined x value is 3-6 (Formula (ii)). The blowing agent is generally a low boiling halogenated alkane, and the surface active agent is preferably a silicone oil, e.g. a polysiloxane-polyoxy-alkylene block copolymer. The fire-retardant may be a tris- (haloalkyl)phosphate, triethyl phosphate, diammonium phosphate, antimony oxide or a phosphorus-containing polyol. Lists of suitable organic polyisocyanates, tertiary amine and tin catalysts, and blowing agents are given. In Example 3 a rigid cellular polyurethane is prepared from the following formulation: (a) an aromatic tertiary amine triol, and an aromatic tertiary amine pentol, (b) crude methylene diphenyl diisocyanate, (c) a polyoxyisopropylene amine of Formula (ii) above wherein x is 2, (d) water and trichlorofluoromethane, (e) dimethylcyclohexylamine and a dialkyl tin dicarboxylate, (f) a silicone surfactant; and tris-(betachloroethyl) phosphate. In Examples 4, 5, the procedure of Example 3 is repeated except that either component (c) is a polyoxyisopropyleneamine of Formula (i) above wherein x is 3, or the blowing agent is trichlorofluoromethane and dichlorodifluoromethane, and polyol component (a) is triethanolamine having 1 propylene oxide moiety per OH terminated group. In Examples 6 and 7 the procedure of Example 4 is repeated except that either (1) component (e) is dibutyltin dilaurate and dimethylethanolamine, or (2) the polyol component (a) is trimethylolpropane having 1 ethylene oxide moiety per OH terminated group and the polyisocyanate (b) is 4,41-diphenyl diisocyanate. The compositions are sprayed on to steel.