| abstract |
PROBLEM TO BE SOLVED: To provide a method for producing an isocyanurate foam which is excellent in dimensional stability and passes JIS flame retardant class 3, without using a special cell communicating agent. SOLUTION: The phthalic acid-based polyester polyol (b) As 1), a polyol (B) containing a polyester polyol containing 25% by mass or more of dipropylene glycol per 100% by mass of a hydroxy compound component, a trimerization catalyst (C) of isocyanate (A), and water as main components. A method for producing a rigid polyurethane foam, comprising reacting an isocyanate group with a hydroxyl group in a polyol component at a molar ratio of 1.5 to 5.0 together with a foaming agent (D), a foam stabilizer (E), and a flame retardant (F). |