| 摘要 |
PURPOSE:To simply and stably obtain the subject foam having uniform and fine cells and excellent in mechanical strength, heat resistance, etc., by melt- blending a polyester having a wide mol.wt. distribution with a foaming agent in an extruder and subsequently extruding the melted product from the extruder under a low pressure for foaming the melted product. CONSTITUTION:A method for producing the objective polyester foam comprises melt-blending a polyester having a mol.wt. distribution of 5-21 (preferably a polyester produced from terephthalic acid as a main component and ethylene glycol as a main glycol component) with a foaming agent (preferably an easily evaporable foaming agent such as CO2 gas or ethane) in an extruder, and subsequently extruding the melted product from the extruder under a low pressure, namely under a lower pressure than the extrusion pressure, to foam the melted product. A multi-functional compound such as glycerol is preferably added as a crosslinking agent for the production of the polyester having the wide mol.wt. distribution. On the production of the polyester, an ester exchange catalyst, a polymerization catalyst, a stabilizer, etc., are preferably used. |
