| 摘要 |
PROBLEM TO BE SOLVED: To obtain an inexpensive polyester resin composition capable of carrying out the crystallization treatment of a mouth stopper part in stable quality in a short time without any dispersion of crystallinity or dimensions after the crystallization of the mouth stopper part. SOLUTION: This composition comprises a polyester resin consisting essentially of ethylene terephthalate unit and having 1.5-3.5 mol.% content [DEG] of diethylene glycol unit in the total diol units and 0.70-0.90 dL/g intrinsic viscosity [η]. The crystallization temperature Tca deg.C at the time of heating up a molded product thereof satisfies conditions of formulae I and II and the Tca deg.C and the crystallization temperature Tcb deg.C at the time of heating up a molded product prepared by carrying out the washing treatment of the polyester resin composition with pure water and then molding the washed composition satisfy formula III. formula I: Tca : 155-165 deg.C, formula II: 115+40×[η]+2×[DEG]<=Tca <=133+40×[η]+2×[DEG] and formula III: Tcb - Tca >=5 deg.C. |
