Caprolactam recovered in process of preparing nylon 6 through hydrolysis ring-opening polymerization of caprolactam and application of cyclic oligomer mixture of caprolactam

Abstract

The invention discloses caprolactam recovered in a process of preparing nylon 6 through hydrolysis ring-opening polymerization of caprolactam and application of a cyclic oligomer mixture of caprolactam. The caprolactam and oligomer mixture mainly comprises caprolactam and other cyclic oligomers, cyclic dimers of alpha and beta crystal forms contained in the caprolactam and oligomer mixture mainly play a role of a nucleating agent, and caprolactam and other cyclic oligomers of tricyclic or more mainly play plasticizing and lubricating roles. The caprolactam and the oligomer thereof have good compatibility with the polyamide engineering plastic material, are uniformly and stably dispersed, can improve the rigidity and toughness of the polyamide engineering plastic at the same time, and have dual functions of lubrication and nucleation.

Description

technical field [0001] The present invention relates to the application of caprolactam and its cyclic oligomer mixture, in particular to the application of caprolactam and its cyclic oligomer mixture recovered in the process of preparing nylon 6 by hydrolysis and ring-opening polymerization of caprolactam in the modification of polyamide engineering plastics The application as a functional additive for lubricating, plasticizing and nucleating belongs to the technical field of polyamide engineering plastic modification additives. Background technique [0002] Caprolactam and oligomers are the products of nylon 6 prepared by hydrolysis and ring-opening polymerization of caprolactam. Nylon 6 slices are extracted with water and the water extraction solution is concentrated by three-effect evaporation. Nylon 6 manufacturers call it concentrated The liquid is mainly composed of caprolactam, and also contains caprolactam cyclic oligomers that are inevitably formed during the hydrol...

AI Technical Summary

Problems solved by technology

[0004] In the existing preparation process of nylon 6 slices by hydrolysis and ring-opening polymerization of caprolactam, the unfavorable factors such as clogging of pipelines, valves, delivery pumps and other unfavorable factors caused by the agglomeration of cyclic oligomers in the extraction concentrate, or the decline in the quality of the prepared nylon 6 slices, or through catalysis Cracking and recovering caprolactam leads to the defect of high polymerization cost. The purpose of the present invention is to provide a kind of caprolactam and its cyclic oligomer as the lubrication, plasticizing and nucleating functional additive application of polyamide engineering plastics. Compared with the existing Imported high-end nucleating agents in the technology, caprolactam and its cyclic oligomers have double-effect functions of nucleation and lubrication, and have good compatibility with polyamide engineering plastics and are easier to disperse, especially caprolactam and its cyclic oligomers are Recycling from nylon 6 waste liquid not only has a good cost advantage, but also can reduce environmental pollution

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