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

A catalyst composition for a polyester manufacturing process, comprising a titanium catalyst and/or an antimony catalyst as main catalyst, and either (i) at least one co-catalyst A, or (ii) at least one co-catalyst B and at least one co-catalyst C, or (iii) a combination thereof, and wherein co-catalyst A is selected from the group consisting of a metal salt of an alkyl or an aryl phosphinic acid, or a metal salt of an alkyl or aryl diphosphinic acid, or a combination thereof, and co-catalyst B is selected from the group consisting of an alkyl or aryl phosphinic acid, an alkyl or aryl diphosphinic acid a combination thereof, and co-catalyst C selected from the group of a metal salt, a metal hydroxide or a metal organyl compound.

A type of fully dull polyester drawn yarns and a preparing method thereof are disclosed. The preparing method is to melt spinning a modified polyester with the fully drawn yarn (FDY) technique, and the modified polyester is a product of an esterification and successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol, a fluorinated dicarboxylic acid, a matting agent, a calcined multiphase solid acid base powder and a doped Bi.sub.2O.sub.3 powder. The obtained fiber has an intrinsic viscosity drop of 18-26% when stored at 25° C. and R.H. 65% for 60 months. The method of improving the degradation performance of polyester fiber through the incorporation of 2,5,6,6-tetramethyl-2,5-heptanediol, the fluorinated dicarboxylic acid, the doped Bi.sub.2O.sub.3 powder and the calcined multiphase solid acid base powder is easy to operate.

A type of feather-like polyester fiber and a preparing method thereof are disclosed. The preparing method is to manufacture filament from a modified polyester through a POY process with a four-fold flat spinneret and a successive DTY processes, wherein said modified polyester is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, main-chain silicated diol and fluorinated dicarboxylic acid, and the spinneret is the one set with four-fold flat shaped orifices. The obtained fiber has a dye uptake of 89.6-93.7% when dyed at 130 C., and has an intrinsic viscosity drop of 13-20% when stored at 25 C. and R.H. 65% for 60 months. This invention is simple to apply and features a product with good dyeing and degradation performance.

A type of fully dull polyester drawn yarns and a preparing method thereof are disclosed. The preparing method is to melt spinning a modified polyester with the fully drawn yarn (FDY) technique, and the modified polyester is a product of an esterification and successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, 2,5,6,6-tetramethyl-2,5-heptanediol, a fluorinated dicarboxylic acid, a matting agent, a calcined multiphase solid acid base powder and a doped Bi.sub.2O.sub.3 powder. The obtained fiber has an intrinsic viscosity drop of 18-26% when stored at 25 C. and R.H. 65% for 60 months. The method of improving the degradation performance of polyester fiber through the incorporation of 2,5,6,6-tetramethyl-2,5-heptanediol, the fluorinated dicarboxylic acid, the doped Bi.sub.2O.sub.3 powder and the calcined multiphase solid acid base powder is easy to operate.

A process for producing a cationic dyeable polyester includes the steps of: (a) subjecting a combination of a bis-hydroxy alkyl terephthalate monomer of Formula (1) defined herein and an organic diacid monomer mixture which includes an aromatic dicarboxylic acid monomer and a sulfo group-containing aromatic dicarboxylic acid dyeable monomer to an esterification reaction to form an esterification reaction product; and (b) subjecting the esterification reaction product to a polycondensation reaction.

A type of feather-like polyester fiber and a preparing method thereof are disclosed. The preparing method is to manufacture filament from a modified polyester through a POY process with a four-fold flat spinneret and a successive DTY processes, wherein said modified polyester is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, main-chain silicated diol and fluorinated dicarboxylic acid, and the spinneret is the one set with four-fold flat shaped orifices. The obtained fiber has a dye uptake of 89.6-93.7% when dyed at 130 C., and has an intrinsic viscosity drop of 13-20% when stored at 25 C. and R.H. 65% for 60 months. This invention is simple to apply and features a product with good dyeing and degradation performance.

A type of semi-dull polyester drawn yarns and preparing method thereof are disclosed. The preparing method is to melt spinning a modified polyester with FDY technique, wherein the modified polyester is the product of the esterification and the successive polycondensation reactions of evenly mixed terephthalic acid, ethylene glycol, main chain silicated diol, fluorinated dicarboxylic acid, matting agent and doped Bi.sub.2O.sub.3, in which the main chain silicated diol could be dimethylsiloxane diol, dimethyldiphenyldisiloxane glycol or tetramethyldisiloxane diol, and in which the fluorinated dicarboxylic acids could be 2,2-difluoro-1,3-malonic acid, 2,2-difluoro-1,4-succinic acid, 2,2-difluoro-1,5-glutaric acid or 2,2,3,3-tetrafluoro-1,4-succinic acid. The obtained fiber has a dye uptake of 87.5-91.8% when dyed at 120 C., and has an intrinsic viscosity drop of 18-26% when stored at 25 C. and R.H. 65% for 60 months. This invention features a method with ease of application and a product with good dyeing and degradation performance.

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.