Continuous hydrolytic polymerization method for recycling caprolactam in green manner

Abstract

The invention relates to a continuous hydrolytic polymerization method for recycling caprolactam in a green manner. Reaction raw materials including caprolactam are sequentially subjected to a ring-opening reaction, a pre-polycondensation reaction and a final polycondensation reaction to prepare polyamide 6, wherein both a pre-polycondensation reaction device and a final polycondensation reactiondevice comprise gas devolatilization spaces, and the gas devolatilization spaces are communicated with a vacuum condensation system; the vacuum condensation system, a condensation storage tank and a vacuum pump are sequentially communicated; and the final polycondensation reaction device is a horizontal continuous reactor and is divided into multiple sections, and during final polycondensation reaction, the pressure of each section is decreased progressively along the advancing direction of the melt. 8-10 wt% of a hot water extractable substance generated by thermodynamic equilibrium in a caprolactam hydrolytic polymerization process can be efficiently and greenly recycled, the hot water extractable substance can be compounded with fresh caprolactam for direct reuse without triple-effect evaporation, the content of the generated polyamide 6 slice hot water extractable substance is low, and molding processing can be carried out without extraction.

Description

technical field [0001] The invention belongs to the technical field of polymer material preparation, and relates to a continuous hydrolysis polymerization method for green recycled caprolactam. Background technique [0002] Nylon fiber has excellent physical properties unmatched by polyester fiber. For example, nylon fiber has higher breaking strength, wear resistance ranks first among general textile fibers, good hygroscopicity, excellent elastic recovery rate and fatigue resistance, and excellent dyeing performance. In addition to the use of clothing and decoration, nylon fibers are also widely used in other industries. For example, new products have been developed in tire cord fabrics, automotive textiles, filter materials, and BCF carpet bulky yarns. There are many varieties of nylon fibers, the main varieties are nylon 6 and nylon 66 fibers, and our country mainly produces nylon 6 fibers. [0003] PA6 polymerization is usually obtained by ring-opening polymerization at...

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the defects of large energy resource consumption and limited content during recycling and compounding existing in the existing polyamide 6 polymerization technology, and to provide a green and efficient continuous hydrolysis polymerization of caprolactam Method, through the extraction of multi-stage vacuum system, the thermodynamic equilibrium products produced in the polymerization process can be efficiently recycled, and the moisture in the recycled materials is reduced, the traditional three-effect evaporation process is eliminated, and the recycled materials are reduced. Energy consumption required for processing

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