| 摘要 |
PROBLEM TO BE SOLVED: To provide a soft polyurethane foam having a very minute cell structure and to provide a sound absorbing material made of the same. SOLUTION: The soft polyurethane foam having the very minute cell structure is obtained by addition of a crosslinking agent and a foaming component to a prepolymer having isocyanate terminals and by foam curing of the obtained mixture. The prepolymer having isocyanate terminals is obtained by a reaction of a polyol component containing at least one kind of a low molecular weight polyol having a number average molecular weight of 400-1,000 and at least one kind of a high molecular weight polyol having a number average molecular weight of 3,000-12,000 with polyisocyanate. A difference in reactivity between the isocyanate terminated prepolymer derived from the low molecular weight polyol and the isocyanate terminated prepolymer derived from the high molecular weight polyol prevents the physical association of the cells and gives the soft polyurethane foam having the minute cell structure. COPYRIGHT: (C)2004,JPO&NCIPI |
