Stabilized polyurethanes

摘要

A polyurethane or polyester urethane or mixed polyether-polyester urethane incorporating as a stabilizer from 0.05 to 7.5% by weight of the polyurethane forming reactants of at least one organic phosphite of the general formula: wherein R1, R2 and R3 are alkyl cycloalkyl, aralkyl, aryl or alkaryl radicals, at least one of R1, R2 and R3 containing at least one fluorine or chlorine substituent are made by incorporating the phosphite in the polyurethane-forming reaction mixture. Many fluorine and chlorine substituted organic phosphites are specified, examples being tri(difluoro chloromethyl) phosphite, tri (2-chloroethyl) phosphite, tri (fluorophenyl ethyl) phosphite, tri (2-chloroanthracyl-5) phosphite and monochloro phenyl dibutyl phosphite. Many polyisocyanates, polyesters, polyethers and optionally cross-linking agents for use in the preparation of the polyurethanes are specified. Catalysts e.g. tertiary amines, organic cobalt, lead and nickel naphthenates, stearates and linoleates and organic stannous and stannic compounds may be used. Other additives e.g. siloxane-oxyalkylene block copolymers, silanes, siloxanes, emulsifiers, carbon black, titanium dioxide, wood flour, metal flakes, natural and synthetic fibres, pigments, dyes, rubber and resins may be present in the reaction mixture. Water alone or in admixture with lithium aluminium hydride is the preferred blowing agent for the production of foams, other blowing agents specified are liquid fluoro- and chloro-fluoro-alkanes and liquefied methane and ethane. In the examples, foamed polyurethanes are made from: (I) an ethylene oxide capped adduct of propylene oxide and glycerol, a silicone block copolymer, water, tolylene diisocyanate, dibutyl tin dilaurate and a chloroalkyl and/or chloroaryl phosphite and (II) a propylene oxide adduct of glycerol, dibutyl tin dilaurate, water and tolylene diisocyanate.