Patent ID: 7588121

Claim:
A process for sound proofing comprising disposing a layer of a flexible polyurethane foam between a sound source and an area to be sound proofed, wherein said flexible polyurethane foam is formed by a process comprising: foaming a starting material composition (B) comprising a high molecular weight polyoxyalkylene polyol (A) having a molecular weight per OH group of 500 to 5000 and an average of 2 to 4 OH groups per molecule, an organic polyisocyanate compound (B), a blowing agent (C) and a catalyst (D) in a closed mold, wherein at least a part of the high molecular weight polyoxyalkylene polyol (A) is a polyoxyalkylene polyol (p) in an amount ranging from 8 to 70 mass % of all polyoxyalkylene polyol present, having at least two hydroxyl groups on the average and has a molecular weight (Mc) per hydroxyl group ranging from 1,800 to 2,800 and a total unsaturation value (USV) of at most 0.08 meq/g, and that the air flowability of a flexible polyurethane foam obtained by foaming the starting material composition (E) in a thickness of 26 mm, is at most 0.085 m 3 /min, and wherein said flexible polyurethane foam, in a sound absorption measuring method which utilizes a method of vertical entry of a flexible polyurethane foam obtained by foaming the starting material composition (E) having a thickness of 26 mm, the sound absorption characteristic at 500 Hz is at least 0.3, and the sound absorption characteristic at 2,000 Hz is at least 0.55.