Production technique and equipment for polymerizing polyamide

Abstract

This invention relates to process and apparatus for producing polyamide. The process comprises: feeding molten hexanolactam, TiO2 and benzoic acid, filtering, polymerizing, granulating, extracting anddrying to obtain the product. The apparatus is composed of a feeding system, a post-polymerizing column, an extracting column, and a drying column, and is automatically controlled by DCS. The hosepipe in the post-polymerizing column increases the heat-exchange surface and ensures uniform heating. The water-sealing upper tank increases the pressure on the slices at the top of the extraction column, and prevents the boiling of the slices. Large pores are uniformly distributed on the cone body of the slice extraction distributor to release bubbles. The extraction water temperature has gradient distribution, thus can well extract both slice monomer and slice oligoer. The drying column utilizes high temperature and low nitrogen flow drying, thus can avoid blockage and well distribute the slices. The drying column has a high volume, thus can prolong the stay time pf the slices, increase the wind amount, effectively control viscosity increase of the solid phase, and improve the quality of the slices.

Description

technical field [0001] The invention relates to a process and equipment for polyamide polymerization production. Background technique [0002] At present, my country's polyamide nylon 6 slice polymerization process mainly refers to imported equipment and foreign advanced technology, which mainly include Gemma, Inventa-Kafischer, Agafel, Noy and so on. However, the imported equipment and technology cannot be used for high-end civilian high-speed spinning chips, especially for high-end fine-denier spinning chips. The problem will be more obvious. The produced chips can only be used to produce conventional chips and low-end engineering plastic chips. , As a result, domestic slices for high-end civilian use mainly rely on imports. The imported equipment is composed of caprolactam melter, titanium dioxide compounder, benzoic acid configurer, caprolactam feeding tower, pre-polymerization tower, post-polymerization tower, pelletizer, extraction tower, drying tower and conveying an...

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Problems solved by technology

[0004] 1. The molecular weight distribution of the polymerization reaction is too wide, and the molecular weight changes greatly;

[0005] 2. The extraction system has the problem that the slices are oxidized and there is no way to extract oligomers;

[0006] 3. The drying temperature is too high, and the slice drying adopts high temperature drying to greatly increase the solid phase viscosity of the slice

[0007] The first problem mainly affects the spinnability of the slices and the strength of the spun filaments, which may easily cause the instability of the spinning assembly; the second problem mainly causes a large number of dead angles in the extraction system, resulting in a large number of yellow chips; 3 problems The drying temperature is high, but the slices are dried by solid-phase viscosification, which will produce a large number of viscose particles, which will cause a large number of floating yarns and broken ends for spinning, which directly affects the spinnability of the slices. sex

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