OPTIMIZED METHOD FOR DEPOLYMERISATION OF POLYESTER CONTAINING POLYETHYLENE TEREPHTHALATE Russian patent published in 2024 - IPC C08J11/24 C08L67/02 

FIELD: chemistry.

SUBSTANCE: invention relates to processing of polymers and specifically to a method for depolymerisation of polyester material containing PET. Proposed method comprises several steps. First, the feed stream is conditioned at temperature of 150 °C to 300 °C for 0.5 s - 20 min, wherein the weight ratio of the sum of the flow of the returned oligomer residues and the flow of the diol to the polyester material ranges from 0.03 to 3.0. Then the polymer mass is depolymerised at temperature of 180 °C to 400 °C for 0.1–10 hours. Thereafter, the diol is separated by gas-liquid separation at temperature of 100 °C to 250 °C. At the next stage, the stream enriched with liquid monomers is divided into a stream of heavy impurities and a pre-purified monomer stream. At the end, decolouration is carried out at temperature of 100 °C to 250 °C and pressure from 0.1 to 1.0 MPa, in presence of adsorbent.

EFFECT: proposed approach allows to optimize the stage of polymer raw material conditioning.

14 cl, 2 dwg, 1 tbl, 1 ex