| 摘要 |
PURPOSE:To provide a process by which a low-density polyurethane foam having an excellent surface state can be demolded in a short time. CONSTITUTION:A process for producing a polyurethane foam having a density of 0.2-0.8g/cm<3> and containing fine cells by reaction-injection molding from a polyisocyanate and a mixture comprising a polyol, a catalyst, a foaming agent, and optional ingredients such as a cross-linking agent, an internal release agent, a reinforcement, and other minor additives, wherein the foaming agent is 0.4-2 pts.wt. formic acid per 100 pts.wt. the polyol mixture and the polyol mixture has a water content of 0.4wt.% or lower. This process is effective in efficiently producing a low-density polyurethane foam having an excellent surface state. By using a tertiary amine catalyst in an increased proportion or by using a neutralizing agent, the service life of the molding machine can be prolonged and the storage stability of the feedstock can be improved. |
