| 摘要 |
PURPOSE:To get rid of the possibility of destroying the ozone layer by using a specified foaming agent when a polyurethane foam is produced by a reaction in the presence of a low-b.p. halogenated hydrocarbon foaming agent. CONSTITUTION:When a foamed polyurethane is produced by reacting an active hydrogen compd. having two active hydrogen functional groups capable of reacting with an NCO group, such as polyether polyol, with a polyisocyanate compd. in the presence of a low-b.p. halogenated foaming agent, at least one compd. selected from the following compd. A to D is used as a foaming agent. It is suitable that the amt. of use is 5-150wt.%, especially 20-60wt.% based on the active hydrogen compd. A: ClFHC-CF2-CF3 (b.p.: 20.2 deg.C), B: F3C-CHCl-CF3 (b.p.: 15 deg.C), C: ClF2C-CF2-CHF2 (b.p.: 21.2 deg.C) and D: ClF2C-CHF-CF3 (b.p.: 16.2 deg.C). |
