| 摘要 |
A method of protecting an organo-tin catalyzed polyether polyurethane foam from dry heat ageing comprises incorporating within the foam-forming ingredients an organo-phosphite of the formula <FORM:0974308/C3/1> wherein R is hydrogen, alkyl, substituted alkyl, cycloalkyl or substituted cycloalkyl. The process is applicable to the production of foams by the one-shot method. The polyether may be the reaction product (M.W. 400 to 6,000) of an alkylene oxide with an initiator such as glycol, trimethylol propane, hexane triol or sorbitol. The organotin compounds include organo-tin oxides, halides and sulphides and organic salts, bis (2-ethylhexyl) tin oxide, 2-ethylhexyl stannonic acid and stannous octoate being specified. In the examples foams are prepared by reacting together polyoxypropylene triol (M.W. 3,000), polyoxyalkylene polydimethylsiloxane block copolymer (surfactant), dibutyl tin dilaurate and triethylamine, water, trichloro-monofluoromethane, tolylene-2, 4- and 2, 6-diisocyanates and the phosphites. The phosphites used are triorganophosphites in which the organo radicals are variously iso-octyl, phenyl and nonylphenyl (for comparison), decyl, octadecyl, tertiarybutyl phenoxyethyl, nonylphenoxypropyl, nonylphenoxyethyl, chloroethyl and chlorododecyl, and also dibutyl and di(2-ethyl-hexyl) hydrogen phosphites. In comparison experiments tertiary butyl-catechol, d-tartaric acid are also used. Specifications 873,697, 892,137 and 945,479 are referred to. |
