Composition for forming semi-rigid polyurethane foam

A composition for forming a semi-rigid polyurethane foam, comprising:

• a polyol mixture (P) containing a polyol composition (A),
• water serving as a foaming agent (C),
• a catalyst (D), and
• a polyisocyanate component (B),
• wherein a content of the foaming agent (C) is 1.5 to 2.2% by weight based on a total weight of (A):
• wherein said polyol composition (A) comprises:
• a polyether polyol (A2), and
• a polymer polyol (A1) obtained by polymerizing a vinyl monomer in a polyether polyol (a) in the presence of a radical polymerization initiator, wherein a content of a polymer of the vinyl monomer is 1 to 7% by weight based on a total weight of (A),
• wherein said polyether polyol (A2) contains a polyether polyol (A21), at a content of (A21) at least 50% by weight based on a total weight of all polyether polyols in the polyol composition (A);
• and
• wherein said polyether polyol (A21) is a polyether polyol which is a polyoxyethylene polyoxypropylene polyol and has an average number of functional groups of 7.8 to 8.2, a hydroxyl value of 20 to 50 mgKOH/g, a content of a terminal oxyethylene units of 5 to 25% by weight and a total content of an oxyethylene units of 8 to 30% by weight,
• wherein an NCO content in (B) is 20 to 30% by weight,
• wherein a weighted average number of functional groups of the polyether polyol (A2) and the polyether polyol (a) in the polyol composition (A) is 6 to 8.