| 摘要 |
PURPOSE:To obtaifn a flame-retardant rigid polyurethane foam, by carrying out the reaction, in the presence of a catalyst, foaming agent, etc., of a polyisocyanate and a lignin-based polyol prepared by the addition of an epoxide to a lignin derivative. CONSTITUTION:The objective polyurethane foam can be obtained by the reaction, in the presence of a catalyst (e.g. organotin compound), a foaming agent (e.g. trichlorofluoromethane), etc., between (A) a polyisocyanate (e.g. tolylene diisocyanate) and (B) a lignin-based polyol[having an average hydroxyl group of 300-650 (pref. 400-600)]prepared by the addition of an epoxide (e.g. alkylene oxide), in the presence of a catalyst (e.g. polyhydric alcohol), to a lignin derivative[a lignin-aldehyde condensate derived from the condensation between ligninsulfonic acid (or its mixture with an appropriate compound) and an aldehyde]. |
