Preparation method of heat-sensitive copolyester fiber

Abstract

The invention relates to a preparation method of a heat-sensitive copolyester fiber. The preparation method comprises the following steps: mixing terephthalic acid, aliphatic diol I, a guide and a titanium-silicon-cobalt composite catalyst uniformly, then subjecting the mixture to an esterification reaction, a pre-polycondensation reaction and a final polycondensation in sequence to obtain heat-sensitive copolyester, and then preparing the heat-sensitive copolyester fiber by melt direct spinning; the aliphatic diol I is propylene glycol or butylene glycol; the guide is an ester compound generated by a reaction between dibasic acid and aliphatic diol II; the molar ratio of the terephthalic acid to the aliphatic diol I is 1:(1.05-1.10); the titanium-silicon-cobalt composite catalyst is formed by compounding a titanium-silicon composite catalyst and a cobalt catalyst; the titanium-silicon composite catalyst is obtained by loading a titanium-based catalyst with a silicon-based catalyst; and polysiloxane and a copolymerization component are added during the final polycondensation reaction. The preparation method provide by the invention is few in side reactions and high in reaction rate; an obtained product is concentrated in molecular weight distribution and good in quality; and the fiber is prepared with the melt direct spinning.

Description

Technical field [0001] The invention belongs to the field of polyester preparation, and specifically relates to a method for preparing a heat-sensitive copolyester fiber. Background technique [0002] Polyester refers to the general term for polymers obtained by polycondensation of polyols and polyacids. Mainly refers to polyethylene terephthalate (PET), customarily also includes linear thermoplastic resins such as polybutylene terephthalate (PBT) and polyarylate. It is a class of polymers with excellent properties and a wide range of uses. It has been widely used in fiber, plastic, film and other fields. In terms of the application of PET in the fiber field, the output of PET fiber in 2017 exceeded 39 million tons. [0003] Along with the diversified demand for clothing fiber products, more and more attention has been paid to the development of new polyester fiber materials, including new polyesters prepared from new monomers and copolyesters modified by copolymerization of exi...

AI Technical Summary

Problems solved by technology

[0006] The following problems exist in the preparation of existing heat-sensitive polyester materials: 1) in the preparation process of heat-sensitive polyester and its copolyester, the molar ratio of dibasic acid to dibasic alcohol-acid in the existing technical system is far high At a ratio of 1:1, diols undergo self-condensation at a high alkyd molar ratio to generate by-products, which have a greater impact on the fiber-forming properties of polyester. At the same time, high molar ratios require more diol raw materials to be consumed. Increase the cost; 2) for polyester, the esterification stage is directly related to the quality of the final polycondensation product. Although some new monomers have huge application potential advantages, their thermal stability is relatively poor, and the prior art has a high alkyd mole It is necessary to carry out sufficient esterification reaction under the esterification time of more than 3 hours, which is very easy to cause the generation of side reactions in the esterification process; To obtain polyester, the intrinsic viscosity of the precondensation product is generally above 0.25dL / g, which causes the molecular weight distribution of the final product to be wide, and the processing performance is not good, and wool, broken ends, waste 4) At present, the melt transportation of heat-sensitive polyester and its copolyester mainly improves the transportation quality by reducing the transportation temperature, but the low-temperature transportation increases the residence time of the melt in the pipeline, and there are still large Viscosity drops, resulting in poor spinnability