Production manner of the polyester type resin foaming body and production mannered null glass transition temperature of the foaming Characteristic

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a resin foamed body by a very simple method of just leaving under normal temperature or using low temperature heating such as hot air or the like, and to provide a method for producing an expandable polyester-based resin material being the raw material of the foamed body. SOLUTION: This method for producing a polyester-based foamed body comprises impregnating a resin material for foaming comprising essentially of a polyester-based resin having glass transition temperature (Tg) of 30 to 80 deg.C with carbon dioxide at an impregnation temperature satisfying the inequality (1): 3 impregnation temperature [ deg.C] = -2.2X+60 to make an expandable resin material, and foaming the expandable resin material at a foaming temperature satisfying the inequality (2): (Tg [ deg.C]-50) = foaming temperature [ deg.C] = Tg [ deg.C] (wherein X denotes an amount (wt.%) of impregnated carbon dioxide in the expandable resin material).