Manufacturing method of copolyester for low acetaldehyde content of PET bottles

摘要

The present invention provides a manufacturing method of copolyester for low acetaldehyde content of PET bottles. The polyethylene terephthalate (PET) polymer is added with an appropriate modifier in order to decrease the production of acetaldehyde caused by pyrolysis side reaction during the blow molding process of PET bottles. The modifier comprises stabilizer and primary antioxidant, wherein the stabilizer is an inorganic phosphorous compound with an addition quantity of 0.003˜0.5 weight % based on the weight of the total copolyester copolymer and the primary antioxidant is a hindered phenolic antioxidant containing Ca^+2 with an addition quantity of 0.005˜5.0 weight % based on the weight of the total copolyester copolymer. The present invention owns an improving effect of decreasing the production of side product—acetaldehyde at least 30% than those without the addition of said modifier.