| 摘要 |
Disclosed is a method for producing a soft polyurethane foam without using a plasticizer, which soft polyurethane foam is excellent in low rebound resilience and durability, while exhibiting less hardness change due to temperature change and having high air permeability. Specifically disclosed is a method for producing a soft polyurethane foam which is characterized in that a polyol mixture is reacted with a polyisocyanate compound in the presence of a foaming agent, a foam control agent and the like at an isocyanate index of not less than 90. The polyol mixture contains a polyol (A) which is composed of a polyether polyol having an average number of hydroxyl groups of 2-3, a hydroxyl number of 10-60 mgKOH/g and an oxyethylene content of 0-30% by mass, a polyol (B) which is composed of a polyether polyol having an average number of hydroxyl groups of 2-3 and a hydroxyl number of 70-250 mgKOH/g, and a monool (D) which is composed of a polyether monool having a hydroxyl number of 10-200 mgKOH/g. The polyol (A) is obtained by ring-opening polymerization of an alkylene oxide using a phosphazene compound, Lewis acid compound or alkali metal compound catalyst as an initiator.
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