▎ 摘　　要

NOVELTY - A polyester composite material is prepared by adding polyglycolic acid, a polymer (a), fillers and additives to a screw extruder, melt-blending at a temperature of 1-50 degrees C which is more than melting point of polyglycolic acid, melt-extruding, lowering the temperature of the molten extrudate, performing primary stretching at a temperature (t1) of 1-100 degrees C which is less than melt temperature of a die of the extruder with a stretching ratio of 2-20, performing secondary stretching at a temperature (t2) of 1-100 degrees C which is more than glass transition temperature of polyglycolic acid with a stretching ratio of 2-15, and heat-treating the stretched extrudate at a temperature (t3) of 10-150 degrees C which is more than glass transition temperature of polyglycolic acid. The polymer (a) is adipic acid/butylene terephthalate copolymer, polycaprolactone, polybutylene succinate, polyhydroxy fatty acid ester, polybutylene succinate/adipate copolymer and/or epoxy group-containing copolymer. USE - Polyester composite material e.g. composite fibers, monofilament, flat yarn, film, sheet, pipe or ribbon is used in agriculture application, packaging application, wire application, rope application and three-dimensional printing application (all claimed). ADVANTAGE - The strong and tough polyester composite material has improved physical property, and mechanical property, such as tensile strength and elongation at break. DETAILED DESCRIPTION - A polyester composite material is prepared by adding polyglycolic acid, a polymer (a), fillers and additives to a screw extruder, melt-blending at a blending temperature of 1-50 degrees C which is more than melting point of polyglycolic acid to obtain a blend, melt-extruding, lowering the temperature of the molten extrudate, performing primary stretching at a temperature (t1) of 1-100 degrees C which is less than melt temperature of a die of the extruder with a stretching ratio of 2-20, performing secondary stretching at a temperature (t2) of 1-100 degrees C which is more than glass transition temperature of polyglycolic acid with a stretching ratio of 2-15, and heat-treating the stretched extrudate at a temperature (t3) of 10-150 degrees C which is more than glass transition temperature of polyglycolic acid, or prepared by adding polyglycolic acid, polymer (a), fillers and additives to screw extruder, melt-extruding at the blending temperature of 1-50 degrees C which is more than melting point of polyglycolic acid, performing primary stretching of the molten extrudate at the temperature (t1) with stretching ratio of 2-20, performing secondary stretching at the temperature (t2) with stretching ratio of 2-15, and heat-treating the stretched extrudate at the temperature (t3). The composite material comprises 20-100 pts. wt. polyglycolic acid, 0-100 pts. wt. polymer (a), 0-30 pts. wt. filler, and 0.1-10 pts. wt. additive. The additive comprises 0.1-10 pts. wt. chain extender and 0-5 pts. wt. antioxidant. The polymer (a) is adipic acid/butylene terephthalate copolymer, polycaprolactone, polybutylene succinate, polyhydroxy fatty acid ester, polybutylene succinate/adipate copolymer and/or epoxy group-containing copolymer.