聚酯生产过程中端羧基的产生与控制及对纺丝的影响

Generation and control of carboxyl end group in polyesterproduction and its influence on spinning

端羧基(—COOH)在聚对苯二甲酸乙二醇酯(PET)切片中的含量是PET的重要品质指标。首先必须明确端羧基含量的高低对于聚酯熔体的影响,如染色性的影响,纺丝断头情况的影响等。因此,在生产过程中必须严格控制其含量,继而进一步讨论影响聚酯熔体中端羧基含量的各种因素。对于聚酯生产中,提出要控制端羧基的含量必须结合生产实际,在酯化阶段及时调整物质的量比EG/PTA、酯化温度、酯化压力、停留时间等;在缩聚阶段及时调整真空度等;在最终产品阶段,及时调整停留时间和温度。

The content of carboxyl terminated group(-COOH)in polyethylene terephthalate(PET)chips is an important quality index of pet.Firstly,the influence of carboxyl content on polyester melt must be clarified,such as the influence of dyeability,spinning end breakage and so on.Therefore,its content must be strictly controlled in the production process,and then various factors affecting the end carboxyl content in polyester melt are further discussed.For polyester production,it is proposed that in order to control the content of terminal carboxyl group,the molar ratio eg/PTA,esterification temperature,esterification pressure and residence time must be adjusted in time in the esterification stage;Adjust the vacuum degree in time in the polycondensation stage;In the final product stage,adjust the residence time and temperature in time.