PROCESS FOR MANUFACTURING POLYETHYLENE TEREPHTHALATE (PET) FROM VIRGIN RAW MATERIAL AND POLYMER RECYCLED FROM PET BOTTLES.

摘要

The process for the manufacture of polyethylene terephthalate (PET), having similar characteristics to virgin PET, from PET bottles recovered from trash cans and virgin raw material (TPA, IPA and EG) is performed in three stages: 1) using a glycolysis process for depolymerizing the recycled PET flake while a direct sterification is performed using a virgin raw material, 2) the monomer or BHT resulting from the previous stage is added with antimony triglycolate and cobalt acetate catalysts in amounts corresponding to 0.028% of antimony triglycolate and 0.019% of cobalt acetate for the monomer resulting from the glycolysis, and 0.04% of antimony triglycolate and 0.03% of cobalt acetate for the BHT resulting from the virgin raw material; the previously filtrated monomer or BHT is transferred to a polymerization reactor while a thermal stabilizer is being charged with 0.014% of phosphoric acid and where the polymerization is performed at temperatures of 290°C and at high vacuum until rea ching an intrinsic viscosity of 0.55 to 0.60, 3) the amorphous polymer obtained in the previous stage is subjected to a post polymerization process at high vacuum and at a temperature of 210°C until reaching an intrinsic viscosity of 0.81 to 0.82.