A method includes depolymerizing post-consumer or post-industrial recycled polyethylene terephthalate (rPET) to form bis(2-hydroxyethyl) terephthalate (BHET), and reacting at least a portion of the BHET with a catalyst to form an alcohol. The alcohol includes cyclohexanedimethanol (CHDM) or 1,4-phenylenedimethanol (PDM). Further steps of the method include polymerizing the alcohol in the presence of additional BHET to form a polyester. The polyester may include poly(cyclohexylenedimethylene terephthalate (PCT), polyethylene terephthalate glycol (PETG) copolyester, polycyclohexylene dimethylene terephthalate glycol (PCTG) copolyester, polycyclohexylene dimethylene terephthalate acid (PCTA), or a monomer having repeating units with the structure (I), wherein n is an integer having a value of at least 20.

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The invention concerns a method for producing a polyester containing at least one 1,4:3,6-dianhydrohexitol unit comprising:.Math.a step of introducing, into a reactor, monomers comprising at least one monomer (A) that is a diacid or a diester and at least one monomer (B) that is a 1,4:3,6-dianhydrohexitol;.Math.a step of introducing, into the reactor, a catalytic system comprising either a catalyst comprising the element germanium and a catalyst comprising the element aluminum, or a catalyst comprising the elements germanium and aluminum, or a mixture of said two catalysts;.Math.a step of polymerising said monomers to form the polyester;.Math.a step of recovering a polyester composition comprising the polyester and the catalytic system. The invention also concerns a polyester composition containing a catalytic system comprising either a catalyst comprising the element germanium and a catalyst comprising the element aluminum, or a catalyst comprising the elements germanium and aluminum, or a mixture of said two catalysts, and the use of same to reduce the colouring of the polyester.

The invention concerns a method for producing a polyester containing at least one 1,4:3,6-dianhydrohexitol unit comprising:.Math.a step of introducing, into a reactor, monomers comprising at least one monomer (A) that is a diacid or a diester and at least one monomer (B) that is a 1,4:3,6-dianhydrohexitol;.Math.a step of introducing, into the reactor, a catalytic system comprising either a catalyst comprising the element germanium and a catalyst comprising the element aluminum, or a catalyst comprising the elements germanium and aluminum, or a mixture of said two catalysts;.Math.a step of polymerising said monomers to form the polyester;.Math.a step of recovering a polyester composition comprising the polyester and the catalytic system. The invention also concerns a polyester composition containing a catalytic system comprising either a catalyst comprising the element germanium and a catalyst comprising the element aluminum, or a catalyst comprising the elements germanium and aluminum, or a mixture of said two catalysts, and the use of same to reduce the colouring of the polyester.

Provided are catalysts, methods of making catalysts, methods of using catalysts, and copolymers made utilizing the catalysts. The catalyst has a metal salen complex group, a bridging group, and one or more co-catalyst groups. The metal salen complex group is attached to the bridging group and the bridging group is attached to the co-catalyst group. The copolymers made utilizing the catalysts are polyesters or polycarbonates.

Provided are catalysts, methods of making catalysts, methods of using catalysts, and copolymers made utilizing the catalysts. The catalyst has a metal salen complex group, a bridging group, and one or more co-catalyst groups. The metal salen complex group is attached to the bridging group and the bridging group is attached to the co-catalyst group. The copolymers made utilizing the catalysts are polyesters or polycarbonates.

To provide a biaxially oriented polyester film that has extremely low content of antimony, excellent hygiene, few foreign substances, excellent transparency and heat resistance, and is excellent in printability, workability, and productivity. A biaxially oriented polyester film characterized by a content of antimony in the film of 10 ppm or less, a content of phosphorus in the film of 25 ppm or more and 75 ppm or less, an intrinsic viscosity of the film of 0.51 dl/g or more and 0.70 dl/g or less, and a number of defects with a size of 1 mm or more is 1.0 or less per 1000 square meters of the film.

Provided are novel dinuclear indium catalysts of formula (A) that are capable of living and immortal ring opening polymerization and copolymerization of cyclic ester monomers for the preparation of biodegradable polymers and copolymers, in particular polyesters. Also disclosed are polymerization methods and polymer products. These dinuclear indium catalysts allow less costly, highly reactive living polymerization of cyclic ester monomers with possible high turn over rates and/or substantial stereo-chemical and microstructure control. ##STR00001##

Provided are novel dinuclear indium catalysts of formula (A) that are capable of living and immortal ring opening polymerization and copolymerization of cyclic ester monomers for the preparation of biodegradable polymers and copolymers, in particular polyesters. Also disclosed are polymerization methods and polymer products. These dinuclear indium catalysts allow less costly, highly reactive living polymerization of cyclic ester monomers with possible high turn over rates and/or substantial stereo-chemical and microstructure control. ##STR00001##

A polyester polymer composition having a polyester polymer with furanic units as well as a process to prepare this polyester polymer composition are herein described. The process includes the step of reacting a cyclic polyester oligomer in the presence of a catalyst in a ring-opening polymerization reaction with a reaction temperature and a reaction time sufficient to yield a polyester polymer having furanic units. The present invention further provides a method of use of this polyester polymer composition in extrusion, injection molding, or blow molding.

A polyester polymer composition having a polyester polymer with furanic units as well as a process to prepare this polyester polymer composition are herein described. The process includes the step of reacting a cyclic polyester oligomer in the presence of a catalyst in a ring-opening polymerization reaction with a reaction temperature and a reaction time sufficient to yield a polyester polymer having furanic units. The present invention further provides a method of use of this polyester polymer composition in extrusion, injection molding, or blow molding.