A kind of method of recycling caprolactam

Abstract

The invention relates to a method for recycling caprolactam. The method comprises the following steps: in the process of synthesizing polyamide 6 from caprolactam, obtaining an extracting solution from a polymerization product by using a vacuum extraction method, mixing the extracting solution, a ring-opening agent, deionized water, fresh caprolactam and a molecular weight regulator according to acertain ratio to obtain a mixture, and sequentially carrying out ring-opening reaction, polycondensation reaction, granulation and melt spinning to obtain the fibers. According to the method disclosed by the invention, 8-10wt% of hot water extractable substances generated by thermodynamic equilibrium in a caprolactam hydrolytic polymerization process can be recycled; moreover, the extracting solution hardly contains water; compared with the prior art, the method has the advantages that the polyamide 6 slices can be directly compounded with fresh caprolactam, wherein the content of generated polyamide 6 slice oligomers is low, forming, processing and spinning can be performed without extraction, time and production cost are greatly saved, adverse effects of high content of cyclic oligomerson product quality and equipment are reduced, and the product quality is improved.

Description

technical field [0001] The invention belongs to the technical field of polymer material preparation and relates to a method for recycling caprolactam. Background technique [0002] At present, my country's polyamide nylon 6 slice polymerization process mainly refers to foreign imported equipment and foreign advanced technology, which mainly include Gemma, Evanda-Car Fischer, Agafel, Noy and so on. The imported equipment and processes are all used from the caprolactam melter, titanium dioxide preparation device, benzoic acid configuration device, caprolactam feeding tower, pre-polymerization tower, post-polymerization tower, pelletizer, extraction tower, drying tower and Ancillary equipment for conveying packaging. The production process of polyamide 6 polymerization is that molten caprolactam is fed together with water and molecular weight regulator, and the product is obtained through pre-polymerization, post-polymerization, pelletizing, extraction and drying. [0003] In...

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects of large energy resource consumption and limited content during reuse and compounding existing in the existing polyamide 6 polymerization technology, and to provide a method for recycling caprolactam, through multi-stage The extraction of the vacuum system enables the efficient recycling of the thermodynamic equilibrium products produced during the polymerization process, and reduces the moisture in the recycled products, so that the recovered oligomers can be directly recycled, eliminating the need for traditional three-effect evaporation process, which reduces the energy consumption required for processing in the recycling process

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