High-viscosity polyamide-6 preparation method

Abstract

The invention discloses a high-viscosity polyamide-6 preparation method. According to the present invention, the polyamide-6 is tackified by using the following methods that the tri-amino end-cappingagent is added to increase the amino terminal content, the conveying pressure between the front polymerization pipe and the rear polymerization pipe is increased, the flat wet slices are obtained through slicing, the solid phase condensation polymerization efficiency in the second-stage drying is improved, and the energy loss is reduced.

Description

technical field [0001] The invention relates to the technical field of polymer polymerization, in particular to a preparation method of high-viscosity polyamide-6. Background technique [0002] Polyamide-6 is a commonly used polymer raw material, mainly used in the fields of spinning and engineering plastics, and its relative viscosity is generally 2.4-3.0. If polyamide-6 is used in the field of polymer films, its relative viscosity is usually required to reach 3.2-4.0, and the relative viscosity essentially reflects the relative molecular weight of the polymer. [0003] The production method of polyamide-6 by hydrolytic polymerization is well known. It is pointed out in the book "Polyamide Resin Handbook" that the relative molecular weight of polyamide is significantly affected by the water content of the reaction system in the later stage of the polymerization process. Therefore, in the actual production process , The core process of manufacturing high-viscosity polyamide...

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Problems solved by technology

[0005] The high relative viscosity polyamide-6 produced by the above method has low content of terminal amino groups, which is unfavorable for dyeing;

[0006] At the same time, in the polymerization process of the above-mentioned manufacturing method, since the melt in the post-polymerization tube already has a certain high relative viscosity, it is difficult to quickly remove the water in the bottom melt. Vacuum degree and the longer residence time of the melt in the post-polymerization tube, the high vacuum degree will aggravate the ring-forming reaction and increase the loss of caprolactam, and the longer residence time will increase the possibility of melt decomposition and carbonization; in the above manufacturing method In the process of solid-state polycondensation, the viscosification efficiency is not high. In order to obtain the target relative viscosity of polyamide-6, the required residence time is longer, the energy consumption is higher, and the possibility of thermal oxidation performance of the chip is correspondingly increased.

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