| 摘要 |
PURPOSE:To make it possible to produce a good expanded synthetic resin having little fear of destroying an ozone layer by reacting a specified active hydrogen compound with a polyisocyanate compound in the presence of a specified low- boiling halohydrocarbon blowing agent. CONSTITUTION:An expanded synthetic resin is produced by reacting an active hydrogen compound having at least two NCO group-reactive active hydrogen functional groups (e.g., a polyether polyol prepared by reacting glycerol with propylene oxide) with a polyisocyanate compound (e.g., polymethylenepolyphenyl isocyanate) in the presence of a low-boiling halohydrocarbon blowing agent. In the above production, trichloromonofluoroethylene is used as said blowing agent. Although trichloromonofluoromethane (hereinafter referred to as R-11) has been chiefly used as a blowing agent, it has a fear of destroying an ozone layer. Because the above blowing agent of this invention has a b.p. of 71.0 deg.C and a double bond, it has little fear of destroying an ozone layer, and because it has a b.p. close to that of R-11, it can be used as a substitute for R-11. |
