| 摘要 |
PURPOSE:To reduce the possibility of destroying the ozone layer which has become an issue in chlorofluorohydrocarbons which have been hitherto used as the foaming agent by using a specified compd. in preparing a foamed synthetic resin such as a polyurethane foam. CONSTITUTION:In a method for preparing a foamed synthetic resin by reacting an active hydrogen compd. contg. 2 or more active hydrogen functional groups reactive with an isocyanate group with a polyisocyanate compd. in the presence of a foaming agent of a low b.p. org. compd., a polyfluoroether is used as the foaming agent. Examples of the polyfluoroethers include CnF2n+1-O-CmF2m+1 (wherein n and m are each 1-5), CnF2n+1-O-(CmF2m-O-)xClF2l+1 (wherein n, m and l are each 1-5 and x is 0. 1 or 2), formula I (wherein n is 1-5 and m is 0 or 1) and formula II (wherein n is 0, 1, 2, 3 or 4). |
