Antimony-free polyester melt preparation system and method for preparing antimony-free polyester fine denier FDY fibers

Abstract

The invention discloses an antimony-free polyester melt preparation system and a method for preparing antimony-free polyester fine denier FDY (Fully Drawn Yarn) fibers. The method comprises the following steps: (1) adding terephthalic acid, ethylene glycol and dihydric alcohol containing branched chains into a first esterification kettle to carry out primary esterification reaction; (2) conveying the primary esterification reaction product into a second esterification kettle, adding a coloring agent and a titanium catalyst, and carrying out secondary esterification reaction; (3) refluxing part of the secondary esterification reaction product into the first esterification kettle, and conveying the rest of the secondary esterification reaction product into a pre-polymerization kettle for reaction to obtain a pre-polycondensation product; (4) conveying the pre-polycondensation product to a final polycondensation kettle for reaction to obtain a polyester melt; and (5) carrying out melt direct spinning on the polyester melt obtained by the final polymerization kettle to obtain the antimony-free polyester fine denier FDY fiber. By improving spinning process equipment and a polyester molecular structure, the esterification rate and esterification rate in the antimony-free polyester filament melt direct spinning process are increased, the melt fluidity is improved, and the quality of the prepared antimony-free polyester filament is improved.

Description

technical field [0001] The invention relates to the technical field of chemical fiber preparation, in particular to an antimony-free polyester melt preparation system and a method for preparing antimony-free polyester fine denier FDY fibers. Background technique [0002] In 2019, the total output of chemical fiber in China has exceeded 70 million tons, accounting for more than 70% of the world, of which the output of polyester accounts for about 80% of the total output of chemical fiber. Polyester is mainly polyethylene terephthalate (PET), also known as polyester. Clothing made of it has good stiffness, is not easy to deform, is quick to wash and easy to dry, and has been used in many fields. The catalysts used to prepare PET by polycondensation are mainly antimony-containing catalysts. The antimony catalyst is reduced to metal antimony in the reaction, making the polyester gray; and antimony is a heavy metal, which is easily leached out in the dyeing process, thereby poll...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the excessively high activity of the titanium-based catalysts in the prior art, which easily causes more side reactions during the melt conveying process, and breaks the molecular chain. Slow spinning speed, broken ends, floating filaments and other phenomena; and the titanium-based catalyst catalyzed the polyester esterification rate slowly, resulting in poor melt uniformity, and at the same time, the melt has poor heat resistance and is easy to degrade, the viscosity drops greatly, and the spinning speed is low. When producing FDY yarn, the number of natural broken yarns is high, so it is difficult to use titanium-based catalysts for direct spinning of antimony-free polyester filament melts. Provide a system for preparing antimony-free polyester melts and prepare antimony-free polyester fine deniers The method of FDY fiber, by improving the spinning process equipment and polyester molecular structure, promotes the esterification rate and esterification rate in the process of direct spinning of antimony-free polyester filament melt, improves melt fluidity, and reduces viscosity drop. , so as to effectively improve the quality of the antimony-free polyester filament

Images