| 摘要 |
PURPOSE:To decrease the amount of a chloro fluorocarbon, to improve the solubility in a polyol and to obtain a rigid polyurethane foam of improved stability of a foam density by reacting a polyol with a polyisocyanate in the presence of a specified blowing aid. CONSTITUTION:A blowing aid which is a mixed solvent is obtained by mixing 40-80wt.% trichloromonofluoromethane with 5-30wt.% methylene chloride and 10-30wt.% n-pentane. A polyol of, desirably, a sucrose type is reacted with a polyisocyanate (e.g., polymeric polyisocyanate), a blowing agent (e.g., water), and the blowing aid in the presence of a surfactant to obtain a foam. |
