Multistage devolatilization device for nylon 6 melt

Abstract

The invention relates to the field of nylon materials, and discloses a multistage devolatilization device for nylon 6 melt. The multistage devolatilization device comprises a devolatilization system and a component collection system which are connected in sequence, wherein the devolatilization system comprises a plurality of devolatilization reaction kettles which are connected in series and / or inparallel; each devolatilization reaction kettle comprises a shell, a hollow rotating shaft, a motor and a devolatilization disc, the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft communicates with a gas inlet, the devolatilization disc is fixed on the hollow rotating shaft, air holes are distributed in the devolatilization disc, and a gas outletof the devolatilization reaction kettle is connected with the component collection system; and the component collecting system comprises a high-boiling-point component removing unit and a low-boiling-point component removing unit which are connected in sequence. According to the invention, efficient devolatilization can be carried out on the nylon 6 melt, the polycondensation reaction of nylon 6can be inhibited in the devolatilization process, influence on a spinning forming process due to the sudden increase of the molecular weight of the nylon 6 under a vacuum condition is avoided, time isprovided for nylon 6 amide exchange, molecular weight distribution is narrowed, and melt quality is improved.

Description

Technical field [0001] The invention relates to the field of nylon materials, in particular to a nylon 6 melt multi-stage devolatilizer. Background technique [0002] The conversion rate of caprolactam hydrolysis polymerization is generally about 90%, which means that about 10% of caprolactam monomers and oligomers (also called hot water extractables) remain in the polymer. The monomers account for about 75%. About 25%), the impurities in these melts have a great influence on spinning. Therefore, before PA6 spinning, the chips need to be extracted. According to FZ / T51004-2011, the hot water extractable content of PA6 chips should be less than 0.5wt% (high-quality product). Nowadays, continuous hot water extraction technology is widely used in industry to extract monomers and oligomers in PA6 chips, so that the extractable content in chips is less than 0.5wt%, which meets the requirements of high-speed spinning. However, a large amount of water and energy are consumed in the pro...

AI Technical Summary

Problems solved by technology

However, to achieve a large amount of hot water extractables removal, the device needs to have a higher devolatilization area and vacuum degree, and under this high-efficiency devolatilization, the molecular weight of nylon 6 will increase rapidly, and the melt viscosity will increase significantly lead to molding difficulties

In addition, how to collect volatiles, avoid pipeline blockage, and effectively reuse volatiles also affects PA6 production efficiency

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