Process for recycling polyesters
AssigneeEastman Chemical Company
InventorsThomas Michael Pell, Jr., Michael Paul Ekart, David Dunlap Cornell, Damon Brian Shackelford, Donald Lee Carver
Life of this patent
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Abstract
A process for producing high quality TPA suitable for PET feedstock material from recycled polyester. The process includes the steps of depolymerizing the polyester to form DMT; separating the DMT from secondary materials; and hydrolyzing the DMT to form TPA. In a preferred embodiment of the invention the recycled polyester is contacted with a component monomer or oligomer thereof to liquefy the polyester prior to depolymerizing the polyester.
Claims23
A process for recycling polyester and producing polyester feedstock material from the recycled polyester, said process comprising the steps of:
- a) depolymerizing said recycle polyester into a product having component ester monomers, esters and oligomers of said polyester;
- b) substantially segregating said ester in said depolymerized product;
- and
- c) hydrolyzing said segregated ester to form a solid polyester feedstock material.
A process for producing TPA from recycled PET comprising the steps of:
- a) depolymerizing said recycle PET into a product comprising DMT;
- b) substantially segregating said DMT from secondary materials;
- and
- c) hydrolyzing said DMT to form TPA.
A process for producing TPA from recycled PET comprising the steps of:
- a) at least partially dissolving said recycled PET using monomers and oligomers of the same component monomers as present in the recycled PET to produce a solution;
- b) transferring said solution to a depolymerizing reactor and contacting said solution with methanol under depolymerization conditions to produce DMT;
- c) substantially segregating said DMT from secondary materials;
- d) hydrolyzing said DMT to form TPA;
- and
- e) recovering said TPA.
A process for producing TPA from a DMT containing material having from about 10 weight % to substantially 100 weight % DMT, said process comprising hydrolyzing said DMT containing material with water in an amount, based on weight, ranging from about 2:1 to about 4:1 water to DMT whereby crystals of TPA are formed.
Dependencies are inferred from the claim text.