| 摘要 |
PURPOSE:To obtain a low-density polyurethane foam without causing scorching, by foaming a specified urethane foaming stock solution in an atmosphere of a reduced pressure. CONSTITUTION:A urethane foaming stock solution is obtained by mixing a polyol (e.g., polyether polyol) with an organic isocyanate (e.g., tolylene diisocyanate) and, optionally, an amine catalyst (e.g., triethylenediamine), a silicone oil, a tin catalyst (e.g., dibutyltin dilaurate), and a blowing agent (e.g., water). This solution is foamed. When it starts rising, the pressure is reduced so that the degree of vacuum may be at least 50mmHg, preferably, 100-500mmHg below atmospheric pressure, and the foaming is continued.
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