Back to results
US 2026/0242561 A1Published application
Method for storing recycled bis(2-hydroxyethyl)terephthalate and method for preparing polyester resin
AssigneeSK Chemicals Co., Ltd.
InventorsHa-Neul KIM, Yoo Jin LEE, Da-Young HWANG
Life of this patent
Estimating the term…
Abstract
A method for storing recycled bis(2-hydroxyethyl) terephthalate and a process for preparing a polyester resin are provided. Recycled bis(2-hydroxyethyl) terephthalate, obtained by depolymerization of a waste polyester, is mixed and stored with a solvent under specific conditions, leading to the stable maintenance of purity and yellowness and the improvement in product quality, including colors, of a final polyester resin prepared therefrom.
Claims15
A method for storing recycled bis(2-hydroxyethyl) terephthalate, which comprises:
- (1) mixing recycled bis(2-hydroxyethyl) terephthalate obtained by the depolymerization of waste polyester with a solvent to prepare a solution of recycled bis(2-hydroxyethyl) terephthalate having a concentration of 95% by weight or less;
- and
- (2) storing the solution of recycled bis(2-hydroxyethyl) terephthalate at a temperature of 120° C. or lower to maintain the YID index defined below to be 2 or less:
- YID index=(YID−YID[day 0])/YID[day 0]
- wherein YID [day 0] is the yellow index of the solution of recycled bis(2-hydroxyethyl) terephthalate when 30 minutes has passed from the preparation thereof in step (1), and YID is the yellow index of the solution of recycled bis(2-hydroxyethyl) terephthalate after storage in step (2).
2 more elements
Dependencies are inferred from the claim text.