GB1499447A - Process for the preparation of materials comprising a polyurethane cellular layer - Google Patents

Abstract

1499447 Materials comprising a polyurethane cellular layer RHONE-POULENC INDUSTRIES 13 Nov 1975 [18 Dec 1974] 46911/75 Heading C3R [Also in Division B2] A process for the preparation of a material comprising a polyurethane cellular layer comprises (a) coating the material with a polyurethane-based expandable composition comprising a polyurethane prepolymer possessing terminal NCO groups and a catalyst for the formation of carbodiimide groups, the prepolymer having been prepared by the reaction of a polyisocyanate with a polyol having an average molecular weight per OH group of 200 to 6000, the polyol having an average number of functional groups of at most equal to 3, the said catalyst being present in an amount from 0À1 to 15% wt. of the prepolymer, and (b) heat treating the coated material at 100‹ to 180‹ C. to cause expansion and cross-linking of the polymer. The catalyst is preferably a phospholine or phospholidine or a sulphide or oxide thereof or a 2,4,6-tri-(dialkanolamine)-triazine. Suitable polyols include diethylene glycol, dipropylene glycol; polyhydroxylic polyethers or polyesters; α,# - dihydroxy - polyesteramides, polyurethanes and hydrocarbons; optionally modified castor oil, and etherified silanols or siloxanes. Suitable polyisocyanates include any aliphatic, cycloaliphatic or aromatic diisocyanate, a diisocyanate/monomeric polyol reaction product or an NCO-terminated polyurethane prepolymer. The catalyst system for the preparation of the prepolymer may be based on malonitrile, an alkali metal hydroxide or tertiary amine and a compound of a metal selected from Co, Sn, Pb, Bi, Fe and Zn. The compositions may comprise 10-200% wt. of fillers and 1-50% wt. of plasticizers based on the weight of the prepolymer, as well as surface-active agents; blowing agents, e.g. water, volatile hydrocarbons or halocarbons; heat stabilizers; flameproofing agents; U.V. absorbers; dyes and pigments. The compositions can be used for coating textiles particularly for coating carpet backings. In the examples, compositions are prepared by mixing (A) an NCO-terminated prepolymer prepared by reacting (1) either a polyether prepared by condensing propylene oxide and ethylene oxide on glycerol or (2) polyoxypropylene glycol and glycerol, with an 80/20 mixture of 2,4- and 2,6-toluene diisocyanate in the presence of aqueous KOH, malonitrile and dibutyltin dilaurate, with (B) 3 - methyl - 1 - phenyl - 1 - phosphocyclopent- 3-ene oxide dissolved in hexamethylphosphotriamide, a silicone/glycol copolymer surface active agent, and optionally either a mixture of calcined clay and rutile titanium oxide, or talc. The compositions are coated on to a tufted carpet and heated at 160‹ C. to form a cellular polyurethane layer on the backing of the carpet.