| 摘要 |
PURPOSE:To obtain a rigid polyurethane foam exhibiting excellent foam filling property and having excellent low-temp. dimensional stability and compression strength by using both of trichlorofluoromethane and a specified aliph. hydrocarbon compd. at a specified ratio as a foaming agent for the preparation of the rigid polyurethane foam. CONSTITUTION:In a method for preparing a rigid polyurethane foam from an org. polyisocyanate, a polyol, a foaming agent, a catalyst, a surface active agent and other auxiliaries, said foaming agent comprises a mixture of trichlorofluoromethane (R-11) with a 2-7C aliph. hydrocarbon compd. in a ratio of 95:5-0:100 (by wt.). As the 2-7C aliph. hydrocarbon compd., open-chain compd. such as pentane, isopentane and hexane and alicyclic compd. such as cyclopentane, cyclohexane and cyclobutane are cited. |
