METHOD FOR PRODUCING SOFT POLYURETHANE FOAM

摘要

Disclosed is a method for producing a soft polyurethane foam, which enables to form a soft polyurethane foam having good cushioning properties by using a raw material derived from a natural fat/oil. The method for producing a soft polyurethane foam comprises a step wherein a polyoxyalkylene polyol (A) containing a first polyoxyalkylene polyol (A1), which is obtained by ring-opening polymerizing an alkylene oxide (c) with a polymerization initiator (b) in the presence of a polymerization catalyst (a), is reacted with a polyisocyanate compound (B) in the presence of a catalyst (C) and a foaming agent (D). The polymerization catalyst (a) is composed of one or more catalysts selected from the group consisting of coordination anionic polymerization catalysts and cationic polymerization catalysts, while the polymerization initiator (b) is composed of a polyol derived from a natural fat/oil, which is obtained by providing a natural fat/oil with a hydroxyl group through a chemical reaction, and has a hydroxyl number of 20-250 mgKOH/g and a ratio of the mass average molecular weight to the number average molecular weight in terms of polystyrene (Mw/Mn) of not less than 1.2.