PROCESS FOR RECYCLING POLYETHYLENE TEREPHTHALATE (PET) FROM PET BOTTLES OR CONTAINERS RECOVERED FROM TRASH CANS.

摘要

The polyethylene terephthalate (PET) bottles and containers recovered from different sources, mainly from trash cans, are transformed into a high quality polymer by a glycolysis process useful for depolymerizing PET and transforming the same into a monomer (BHT), said process consisting in charging the depolymerization reactor with a predetermined amount of foils and ethylene glycol in a time period of 90 minutes over a base batch of BHT (bis-2 hydroxy-ethyl-terephthalate), which contains small amounts of cobalt acetate (0.019 % by weight) and antimonium trioxide (0.028 % by weight), with a nitrogen stream. The amount of the added charged foil includes a ratio of from about 1/1.61 to about 1/1.38 with regard to the base batch weight and the foil weight, the amount of ethylene glycol required for performing the depolymerization corresponds to a molar ratio of 1.5 of ethylene glycol, including ethylene glycol of the PET foils, added to the acid component of the PET foil at a temperature of from about 210 degree C to about 250 degree C. The process requires a waiting period of 90 minutes following the depolymerization completion, while a pressure of 0.1 kg/cm2 is maintained in the depolymerizator with nitrogen, the catalysts being subsequently added, and the polymerization reactor charged with BHT; a BHT portion is once again left as a base batch.