PROCESS TO SYNTHESIZE HYDROXYL AND CARBOXYL FUNCTIONAL OLIGOMERS FROM RECYCLED POLYETHYLENE TEREPHTHALATE AND PRODUCTS THEREOF

Fecha de publicación: 12/01/2023
Fuente: Wipo Milk or dairy products
A process to synthesize hydroxyl or carboxyl functional oligomers from recycled PET (r-PET) through controlled depolymerization is disclosed. The r-PET chips are cleaned by a plurality of wash cycles to obtain clean r-PET chips. The clean r-PET chips are free of impurities and have a size in a range of up to 2 mm. The cleaned r-PET chips are dried and are subjected to a controlled depolymerization in presence of glycerine with or without a triglyceride to obtain hydroxyl functional oligomers. The controlled depolymerization is carried out at a temperature in a range of 230 ºC to 280 ºC and for a period of 30-180 minutes. The hydroxyl functional oligomers are reacted with anhydrides or polyfunctional carboxylic acids to yield carboxyl functional oligomers directly, avoiding formation of unusable moieties.