| 摘要 |
A rigid closed-cell polyurethane foam is obtained by reacting an aromatic polyiso cyanate in the presence of a blowing agent with a polyether polyol of hydroxyl number 400-600 obtained by bringing propylene oxide into contact with a mixture of triethanolamine and, as co-initiator, sucrose, sorbitol or a -methyl glycoside, the co-initiator being present in an amount of 55 to 575 parts by weight per 100 parts by weight of triethanolamine and the temperature of the mixture being maintained at 60-140 DEG C. The preferred polyisocyanate is tolylene diisocyanate or a mixture of its monomers and the foaming agent may be a saturated aliphatic halocarbon or carbon dioxide. An activator or catalyst, e.g. an organo-tin compound, an organic tin salt or a mixture thereof, and a dispersing agent or emulsifier, e.g. polyethylene oxide phenyl ethers, blends of polyalcohol carboxylic acid esters, oil-soluble sulphonates and siloxane-oxyalkylene block copolymers, may be present and the foam may also contain a cross-linking agent, an auxiliary blowing agent and pigments.ALSO:Polyether polyols are obtained by bringing propylene oxide into contact with a mixture of triethanolamine and, as co-initiator, sucrose, sorbitol or a -methyl glycoside, the co-initiator being present in an amount of 55 to 575 parts by weight per 100 parts by weight of triethanolamine, the temperature of the mixture being maintained at 60-140 DEG C. and the contacting of the mixture with propylene oxide being continued until a polyether polyol having a hydroxyl number of 400-600 is obtained. The reaction is preferably effected in the absence of oxygen at atmospheric or superatmospheric pressure and after reaction the product may be stripped with nitrogen, filtered and treated with an antioxidant, e.g. di-t-butyl-4-methylphenol. |
