The present disclosure relates to a polyester copolymer having excellent strength and heat resistance, and a product comprising the same.

In the present disclosure, it is possible to identify and select recycled bis-2-hydroxyethyl terephthalate of a certain quality or higher, and thus the quality of a polyester resin prepared using the recycled bis-2-hydroxyethyl terephthalate can be improved.

The present invention relates to a polyester container. The polyester container is formed from a polyester resin containing a particular content of diol moieties derived from isosorbide and diethylene glycol, and thus can show high transparency in spite of a great wall thickness thereof.

The present invention relates to a polyester fiber, a preparation method thereof and a molded article prepared therefrom. The polyester fiber comprises a diol moiety derived from isosorbide in a specific amount and is formed into a polyester resin having a specific oligomer content, thereby providing a molded article having excellent saline water resistance, chemical resistance, light resistance and good knot strength, and capable of maintaining high transparency.

The present invention relates to a polyester fiber, a preparation method thereof and a molded article prepared therefrom. The polyester fiber comprises a diol moiety derived from isosorbide in a specific amount and is formed into a polyester resin having a specific oligomer content, thereby providing a molded article having excellent saline water resistance, chemical resistance, light resistance and good knot strength, and capable of maintaining high transparency.

A polyester single layer film according to an embodiment of the present invention has low haze and low oligomer characteristics, has a more bluish color coordinate, and has a low inorganic metal content. Accordingly, the polyester single layer film may be used as a base film of a heat-resistant protective film and a light-scattering preventive film, as well as an ITO and non-ITO base film (for Ag nanowire, or the like) used in recent touch panels. In addition, since the transmittance at a wavelength of 550 nm is relatively high due to less impurity, the polyester single layer film may be used as a base film of a prism for a backlight unit (BLU) and a diffusion sheet.

The invention concerns a method for producing a polyester containing at least one 1,4:3,6-dianhydrohexitol unit comprising: 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; 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; a step of polymerizing said monomers to form the polyester; 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 coloring of the polyester.

Provided is a method for producing a bio-PET resin derived from substantially 100% a biomass resource, using a raw material derived from a carbon-neutral biomass resource as much as possible in place of a raw material derived from a petroleum resource. Ethylene glycol derived from a biomass resource is polymerized with terephthalic acid derived from a biomass resource in the presence of a catalyst containing an aluminum compound or a germanium compound.

A stretched polyester film and a method for preparing the stretched polyester film are disclosed. The stretched polyester film contains a polyester resin in which a diol component and a dicarboxylic acid component are polymerized, wherein the heat shrinkage rate of the film at 80? C. in the main shrinkage direction is 40% or more, and, upon a first thermal treatment and a second thermal treatment, a first melting temperature (T.sub.m1) and a second melting temperature (T.sub.m2) appear when the film is analyzed by differential scanning calorimetry (DSC). The stretched polyester film has excellent heat shrinkability, along with an increased efficiency of a recycling process of waste plastic containers.

A process to produce a copolyester is provided comprising: a. polymerizing 1) at least one terephthalate monomer; 2) about 85 to about 96 mole % of ethylene glycol; and 3) about 4 to about 15 mole % of a combination diethylene glycol (DEG) and at least one glycol residue selected from the group consisting of 1,4-cyclohexanedimethanol residues (CHDM), monopropylene glycol residues (MPG), and 2,2,4,4-tetramethy-1,3-cyclobutane diol residues (TMCD); in the presence of a germanium catalyst to produce the copolyester; wherein the germanium catalyst is present in the copolyester at a concentration of about 5 to about 500 ppm based on elemental germanium; wherein the diacid is based on the substantially equal diacid equivalents of 100 mole % to diol equivalence of 100 mole % for a total.