| 摘要 |
PURPOSE:To produce a highly resilient polyurethane foam having a low density by reacting a polyol with a polyisocyanate contg. diphenylmethane diisocyanate (deriv.) in the presence of a specific catalyst, a blowing agent contg. water, and a foam stabilizer. CONSTITUTION:In a process for producing a polyurethane foam by reacting a polyol with a polyisocyanate in the presence of a catalyst, a blowing agent, and a foam stabilizer, the following components are used: a polyisocyanate at least contg. diphenylmethane diisocyanate and/or a mixture thereof with a deriv. thereof; a blowing agent contg. water and a halogenated hydrocarbon (e.g. trichloromonofluoromethane) in an amt. of the blowing agent of 2 pts.wt. or higher and in an amt. of the halogenated hydrocarbon of 20 pts.wt. or lower (both based on 100 pts.wt. polyol); and a catalyst comprising an imidazole compd. of the formula (wherein R<1> is 1-4C alkyl, benzyl, vinyl, etc.; R<2> is H, 1-4C alkyl, allyl, phenyl, etc.; and R<3> and R<4> are each H, 1-4C alkyl, or hydroxymethyl). Thus, a decrease in the density of a high-resilience foam is achieved. |
