Process for production of polyester polymer for food packing

摘要

Polyethylene terephthalate having an acetaldehyde content of less than 2.5 ppm and suitable for packing of food and beverages intended for human consumption is produced by heating polyethylene terephthalate having an intrinsic viscosity of about 0.5-0.85 at a temperature of 180 DEG -230 DEG C., preferably 200 DEG -220 DEG C., for about 4 to 12 hours. The polyethylene terephthalate must not include more than 25 ppm of ester interchange catalyst or 20 ppm of phosphorous during this heating.