A method for obtaining purified diester effluent by depolymerization of polyester containing opaque polyethylene terephthalate.
The method addresses the impurity issues in depolymerizing colored and opaque PET by a glycolysis process with multi-step purification, achieving high-purity diester effluents for recycling into virgin PET.
JP7870249B2Active Publication Date: 2026-06-04IFP ENERGIES NOUVELLES
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- IFP ENERGIES NOUVELLES
- Filing Date
- 2020-12-07
- Publication Date
- 2026-06-04
Smart Images
Figure 0007870249000001
Abstract
The present invention relates to a method for depolymerizing polyester fillings containing opaque PET, comprising: a) a conditioning step; b) a glycolysis step carried out in the presence of a diol at 180-400°C with a residence time of 0.1-10 hours; c) a step of separating the diol at a temperature of 100-250°C and at a pressure lower than that of step b) to produce a diol effluent and a monomer-rich effluent; d) a step of separating the monomer-rich effluent into a heavy impurities effluent and a pre-purified monomer effluent at a temperature below 250°C and a pressure below 0.001 MPa with a residence time of less than 10 minutes; and e) a step of decolorizing the pre-purified monomer effluent by adsorbing a mixture comprising 20-90 wt. % of the pre-purified monomer effluent and a solvent in the presence of at least one adsorbent at a temperature of 100-200°C and a pressure of 0.1-1.0 MPa.
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