Preparation method for copolyester containing sodium sulfonate group

Abstract

The invention belongs to the field of processing of high polymer materials, and discloses a preparation method for copolyester containing a sodium sulfonate group. The preparation method comprises thefollowing steps: (1) fully mixing dicarboxylic acid, dihydric alcohol and a reaction auxiliary agent, and carrying out a pre-esterification reaction; (2) when the esterification rate of the pre-esterification reaction reaches 50%-85%, adding a mixed solution of a sodium sulfonate group containing monomer and dihydric alcohol, continuously carrying out an esterification reaction, and extracting excessive dihydric alcohol in the esterification reaction through a separation tower until the esterification rate reaches 90% or above; and (3) continuously subjecting an oligomer obtained by the esterification reaction to a condensation polymerization reaction so as to obtain a copolyester chip capable of meeting spinning requirements. The preparation method for the copolyester provided by the invention is stable in process, obtains the copolyester with high melting point and good spinnability, solves the problem of material entrainment of a condensation polymerization vacuum system, and facilitates continuous production.

Description

technical field [0001] The invention belongs to the field of polymer material processing, and in particular relates to a preparation method of copolyester containing sodium sulfonate groups. Background technique [0002] The molecular structure of polyethylene terephthalate (PET) is highly symmetrical and regular, its fiber crystallinity and orientation are high, and the dye-friendly polar groups are less, resulting in poor dyeing performance and harsh dyeing conditions. It needs to be dyed with disperse dyes under high temperature and high pressure conditions. When PET fiber is blended with silk, wool and other fibers, if the dyeing process conditions are not properly controlled, it is easy to cause damage to silk and wool fibers, thus limiting its development and application to a certain extent. [0003] In order to improve the dyeing performance of conventional PET, a monomer (third monomer) containing a sodium sulfonate group is usually added in the production of conven...

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Problems solved by technology

[0004] In the production process of cationic dyeable polyester, the concentration of three monomers used is generally 20%-40%, and the remaining components are ethylene glycol. The timing of adding three monomers in production is generally after the completion of esterification ( The esterification rate is more than 90%), before the pre-condensation polymerization. At this time, the addition of three monomers will cause a large amount of ethylene glycol components to enter the polycondensation system. This component is not needed in production, and a large amount of ethylene glycol During the extraction process through the vacuum means of the polycondensation system, it is very easy to cause material entrainment and blockage of the vacuum system, thereby limiting its continuous production; China Textile Science Research Institute Juyou Chemical Co., Ltd. Ma Li et al. The monomer sodium isophthalic acid-5-sulfonate containing sodium sulfonate group was added before, and the esterification and polycondensation reactions were carried out after thorough mixing, but the final product had poor structural regularity and a low melting point (<200°C) , limiting its application in fiber production

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