| 摘要 |
PURPOSE:To produce a rigid foam without causing any problem of impairing the properties in the presence of a hydrogen-containing halohydrocarbon blowing agent by using a specified modified active hydrogen compound. CONSTITUTION:A process for producing a rigid foam by reacting an active hydrogen compound with a polyisocyanate compound in the presence of a halohydrocarbon blowing agent and assistants such as a catalyst, wherein part of the whole of the active hydrogen compound comprises an active hydrogen compound (desirably of a hydroxyl value of 200-800) modified with an NCO group or an isocyanate compound (desirably a polyisocyanate compound of an NCO content of about 15wt.% or above), and part or the whole of the halohydrocarbon blowing agent comprises a hydrogen-containing halohydrocarbon blowing agent (e.g. 1,1-dichloro-2,2,2-trifluoroethane). According to the above process, a rigid foam which is equivalent to that obtained when the conventional halohydrocarbon blowing agent is used can be produced even when the hydrogen-containing halohydrocarbon blowing agent is used. |
