Method for inhibiting side reaction of tetrahydrofuran in polymerizing process

Abstract

The invention relates to a method for inhibiting the side reaction of tetrahydrofuran in a polymerizing process. According to the method, in the process of preparing a polymer by using terephthalic acid and 1,4-butanediol as main raw materials, ester, titanium-silicon-cobalt composite catalyst dispersant and pH regulator are generated by adding the terephthalic acid and dihydric alcohol in the esterifying stage, the molar ratio of the terephthalic acid to the 1,4-butanediol is controlled to be 1:(1.05-1.10) to inhibit the side reaction of tetrahydrofuran, so that the content of tetrahydrofuranin the polymer is less than or equal to 10wt%; the dispersing medium in the titanium-silicon-cobalt composite catalyst dispersant is 1,4-butanediol, and the titanium-silicon-cobalt composite catalystis prepared by combining a titanium-silicon composite catalyst and a cobalt catalyst, and the titanium-silicon composite catalyst is prepared from a silicon catalyst-supported titanium catalyst. According to the method for inhibiting the side reaction of tetrahydrofuran in a polymerizing process, the final product has concentrated molecular weight distribution, few byproduct and high quality, andhas a great application prospect.

Description

Technical field [0001] The invention belongs to the field of polyester preparation, and relates to a method for inhibiting the side reaction of tetrahydrofuran in the polymerization process, in particular to a method for inhibiting the side reaction of tetrahydrofuran in the polymerization process of PBT polyester or copolyester. Background technique [0002] Polybutylene terephthalate (PBT) has excellent crystallization properties, heat resistance, chemical resistance, molding properties and low moisture absorption. It is a new type of material with excellent comprehensive properties. At present, the polymerization process of PBT fiber is developed by the polymerization process of PET fiber, and there are still many problems in the polymerization process. For example, the raw materials of PET are terephthalic acid and ethylene glycol, and the raw materials of PBT are terephthalic acid and 1,4-butanediol. The main difference between the two systems is the number of carbon atoms i...

AI Technical Summary

Problems solved by technology

However, there are still some problems with titanium-based catalysts: high catalytic activity, yellow color of the sample and easy hydrolysis of titanium-based catalysts in the polymerization process, thereby reducing catalytic activity, etc. It is necessary to further improve the polymerization process

Although the above method suppresses side reactions to a certain extent, there are problems such as a large alkyd molar ratio in the above two methods, resulting in waste of raw materials and unsatisfactory effects of suppressing byproducts.