Polyester polymer recovery
AssigneeMonsanto Company
InventorsNorman C. Sidebotham, Paul D. Shoemaker, Clarence W. Young, III
Life of this patent
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Abstract
Polyester fibers are dissolved and solid linear polyester polymer recovered for use in the production of new linear polyester products, particularly polyester fibers or filaments, by the process of dissolving the fibers in a non-depolymerizing dissolution solvent for polyester characterized by inclusion of carbocyclic rings in its structural formula under dissolution conditions for polyester polymer; thereafter quenching the polyester solution; and separating the solid polyester from the solution.
Claims22
A process for recovering solid linear polyester polymer from polyester fibers which comprises the steps of:
- a. dissolving the polyester fibers in a non-depolymerizing dissolution solvent for polyester under conditions permitting dissolution of high molecular weight polyester without loss of more than 15% of such molecular weight, to form a solution;
- b. quenching the solution under such conditions that the polyester polymer is caused to precipitate out in a form having a molecular weight of within 15% of the molecular weight of the fibers leaving the solvent in liquid phase;
- and,
- c. separating the precipitated polyester polymer from the non-depolymerizing solvent.
A process for recovering solid linear polyester polymer from polyester fibers which comprises the steps of:
- a. dissolving the polyester fibers in a non-depolymerizing dissolution solvent for polyester under conditions permitting dissolution of high molecular weight polyester without loss of more than 15% of such molecular weight, to form a solution;
- b. quenching the solution with a liquid quenching medium under such conditions that the polyester is caused to precipitate out in a form having a molecular weight of within 15% of the molecular weight of the fibers leaving the solvent and the quenching medium in liquid phase;
- c. and separating the precipitated polyester polymer from the solvent and the quenching medium.
Dependencies are inferred from the claim text.