| 摘要 |
PROBLEM TO BE SOLVED: To provide a novel organic filler exhibiting, within a film, the function of a filler and capable of easily yielding a film unaccompanied by defects, specifically accompanied, at a recovery step, neither by a film productivity loss attributed to a deficient miscibility with polyester nor by film defects attributed to gelation and, if necessary, soluble within the polyester at a recovery and recycling step.SOLUTION: The sought objective is achieved by polyester particles consisting of a polyethylenenaphthalate with which 1-8 mass% of a polytetramethylene glycol having a number-average molecular weight of 3000 has been copolymerized and whose average particle diameter, specific gravity, and melting point are respectively 10-400 μm, 1.34-1.39, and 280°C or above. |
