Preparation of low-acid polyalkylene terephthalate and preparation of macrocyclic polyester oligomer therefrom
AssigneeCyclics Corporation
InventorsPeter Phelps, Gary Faler
Life of this patent
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Abstract
The invention provides methods and systems for manufacturing low-acid polyalkylene terephthalate, for example, polybutylene terephthalate (PBT). The invention also provides methods and systems for preparing macrocyclic polyester oligomer (MPO) from low-acid polyalkylene terephthalate. Finally, the invention provides methods and systems for preparing MPO via reaction of a diol and a dialkyl ester in an organic solvent to form non-isolated, low-acid polyalkylene terephthalate which undergoes cyclization (depolymerization) to form MPO.
Claims52
A method for preparing a low-acid polybutylene terephthalate product, the method comprising the step of exposing a mixture to a temperature no greater than about 240° C. at a pressure no less than about atmospheric pressure, the mixture at least initially comprising:
- (a) butanediol;
- (b) dimethylterephthalate;
- (c) an organic solvent;
- and
- (d) a catalyst.
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A method for preparing a macrocyclic polyester oligomer, the method comprising the step of exposing a mixture to heat, the mixture comprising:
- a polybutylene terephthalate polymer having an acid concentration no greater than about 10 meq/kg;
- an organic solvent;
- and
- a depolymerization catalyst.
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A method for preparing a macrocyclic polyester oligomer, the method comprising the steps of:
- (a) exposing a mixture to a temperature no greater than about 240° C. at a pressure no less than about atmospheric pressure thereby forming a mixture comprising polymer solids, the mixture at least initially comprising:
- (i) a diol;
- (ii) at least one member selected from the group consisting of an acid, an ester, a diacid, a diester, a dicarboxylic acid, and a dialkyl ester;
- (iii) an organic solvent;
- and
- (iv) a catalyst;
- (b) maintaining a concentration of polymer solids in the mixture within a first range;
- (c) reducing the concentration of polymer solids following step (b);
- and
- (d) maintaining the concentration of polymer solids in the mixture within a second range in the presence of heat, thereby producing a macrocyclic polyester oligomer.
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A continuous process for preparing a macrocyclic polyester oligomer, the process comprising:
- a first unit operation having an output stream, wherein the first unit operation is adapted to expose a mixture to a temperature no greater than about 240° C. at a pressure no less than about atmospheric pressure thereby forming polymer solids, the mixture comprising 1,4-butanediol, dimethylterephthalate, an organic solvent, and a catalyst;
- and
- a second unit operation having an input stream that comprises at least a portion of the output stream of the first unit operation, wherein the second unit operation is adapted to expose the input stream to heat, thereby producing a macrocyclic polyester oligomer.
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A method for preparing a low-acid polybutylene terephthalate product, the method comprising the step of exposing a mixture to a temperature no greater than about 240° C. at a pressure no less than about atmospheric pressure, the mixture at least initially comprising:
- (a) one or a combination of:
- (i) butanediol;
- (ii) dimethyl terephthalate;
- (iii) terephthalic acid;
- and
- (iv) a reaction product of two or more of (i), (ii), and (iii);
- (b) a solvent;
- and
- (c) a catalyst.
A method for preparing a macrocyclic polyester oligomer, the method comprising the steps of:
- (a) exposing a mixture to a temperature no greater than about 240° C. at a pressure no less than about atmospheric pressure thereby forming a mixture comprising polymer solids, the mixture at least initially comprising:
- (i) one or a combination of:
- (A) a diol;
- (B) at least one member selected from the group consisting of an acid, an ester, a diacid, a diester, a dicarboxylic acid, and a dialkyl ester;
- (C) a reaction product of (A) and (B);
- (ii) an organic solvent;
- and
- (iii) a catalyst;
- (b) maintaining a concentration of polymer solids in the mixture within a first range;
- (c) reducing the concentration of polymer solids following step (b);
- and
- (d) maintaining the concentration of polymer solids in the mixture within a second range in the presence of heat, thereby producing a macrocyclic polyester oligomer.
Dependencies are inferred from the claim text.