| 摘要 |
PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam that is excellent in working environment and the like and is excellent in flame retardancy.SOLUTION: A composition for forming a water-expanded rigid polyisocyanurate foam includes (A) an organic polyphenyl methane polyisocyanate, (B) a polyol, (C) a trimerization catalyst, (D) water as a foaming agent, (E) a foam stabilizer and (F) a flame retardant and is characterized in that the polyol (B) contains (b1) a chlorinated polyether polyol having primary and/or secondary hydroxyl groups which is produced by conducting ring-opening polymerization of a chlorinated epoxy compound represented by formula (1) in the presence of an acid catalyst using an active hydrogen-containing compound as a polymerization initiator and that the organic polyphenyl methane polyisocyanate (A) and the polyol (B) are used to have an isocyanate index of 120 to 400. |
