To provide a flexible
polyurethane foam which is excellent in low resiliency and durability without using a
plasticizer and which shows little change in
hardness against a change in temperature and at the same time, has high air flow.A process for producing a flexible
polyurethane foam, which comprises reacting a
polyol mixture comprising the following
polyol (A), the following
polyol (B) and the following monool (D) with a polyisocyanate compound in the presence of a
blowing agent and a foam stabilizer, at an
isocyanate index of at least 90, wherein:
Polyol (A) is a polyether polyol having an average of from 2 to 3 hydroxyl groups, a
hydroxyl value of from 10 to 60 mgKOH / g and an oxyethylene group content of from 0 to 30
mass %, obtained by ring-opening
polymerization of an alkylene
oxide to an initiator using a
phosphazene compound, a Lewis acid compound or an
alkali metal compound catalyst;
Polyol (B) is a polyether polyol having an average of from 2 to 3 hydroxyl groups and a
hydroxyl value of from 70 to 250 mgKOH / g; andMonool (D) is a polyether monool having a
hydroxyl value of from 10 to 200 mgKOH / g.