| 摘要 |
PURPOSE:To prepare a sheet pad being made soft with excellent moldability and physical properties without inducing destruction of environment and with high reactivity and short curing time by incorporating a specified amt. of propylene carbonate in an isocyanate component. CONSTITUTION:In a method wherein a urethane sheet pad is prepd. by casting an isocyanate component and a polyol component in a mold and performing foam-molding thereof, an isocyanate component incorporated with 1-20 wt.% propylene carbonate is used. When the amt. of propylene carbonate is less than 1 wt.%, an effect of making the sheet pad soft is small and when it exceeds 20 wt.%, the mechanical strength such as tensile elongation and tearing strength of the sheet pad becomes extremely worse and the reactivity during molding is lowered and the curing time is prolonged. It is possible by this method to prepare a sheet pad being made soft with excellent moldability and physical properties without inducing destruction of environment and with high reactivity and short curing time. |
