| 摘要 |
PURPOSE:To produce a urethane foam exhibiting stable foaming and free from cracks by using a specific nonhydrolyzable linear siloxane-polyoxyalkylene block copolymer as the foam stabilizer. CONSTITUTION:A surfactant comprising a nonhydrolyzable linear siloxane- polyoxyalkylene (A-B)n block copolymer of the formula (wherein R is a monovalent hydrocarbon group having no aliph. unsatd. bond; n is 2-4; a>=6; b>=4; c>=2; and Y is a divalent org. group) is used as the foam stabilizer for producing a urethane foam. In the block copolymer, the average mol.wt. of block A is about 400-10,000; that of block B is about 200-10,000; and block B contains, on average, about 50-80wt% ethylene oxide units. The copolymer comprises about 10-95wt.% blocks A and about 90-5wt.% blocks B and has an average mol.-wt. of about 1,200 or higher. |
