| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for producing a low-density rigid polyurethane foam excellent in compression strength and long-term dimensional stability and a method for using a low-density rigid polyurethane foam produced thereby. SOLUTION: In this process, a (modified) org. polyisocyantate (a) is reacted with a high-molecular compd. (b) having at least two reactive hydrogen atoms and if necessary a low-molecular chain extended and/or a cross-linker (c) in the presence of a blowing agent (d), a catalyst (e), and if necessary other auxiliaries and/or additives (f). Here, the blowing agent (d) comprises 0.1-10 wt.% cyclopentane, 0.1-6 wt.% compd. homogeneously miscible with cyclopentane and selected from among 3-4C alkanes and 3-4C alkenes, and carbon dioxide generated by the reaction of water with the isocyanate (a); and a polyether having arom. parts and nitrogen atoms is used in an amt. of 5-25 wt.% as the high mol.wt. compd. (b). |
