Continuous precipitation grading plant and method for polymer

Abstract

The invention discloses a continuous polymer precipitation-fractionation device and a continuous polymer precipitation-fractionation method. The continuous polymer precipitation-fractionation device comprises a separation column; the lower part of the separation column is provided with a precipitator feed-in port, the upper part thereof is provided with a low molecular weight polymer solution discharge port, and the bottom end thereof is provided with a high molecular weight polymer solution discharge port; a polymer solution feed-in pipe passes through the top of the separation column and extends into the separation column; the lower part of the polymer solution feed-in pipe takes the shape of a tower-shaped spiral which is positioned between the low molecular weight polymer solution discharge port and the precipitator feed-in port; the lower end of the polymer solution feed-in pipe is sealed; and the tower-shaped spiral part of the polymer solution feed-in pipe is provided with a hole, and the opening of the hole faces downwards or points to the center of the separation column. The continuous polymer precipitation-fractionation device can improve the separation efficiency and achieve the industrial scale separation, is applicable to continuous precipitation and fractionation for ordinary polymers, and is especially effective in the fractionation of polymers such as polyurethane, polyester, and the like, which easily form large precipitation balls or grains or precipitation fibers.

Description

technical field [0001] The invention relates to a polymer classifying device and method, in particular to a polymer continuous precipitation classifying device and method. Background technique [0002] Polymers have a certain molecular weight distribution. In order to meet specific usage requirements, the synthesized polymers must be fractionated and purified. Especially when it is used as a biomaterial, it is necessary to separate the low molecular weight part so that the polymer has excellent mechanical properties and anti-degradation properties. For example, polyurethane is a widely used biological material. However, the principle of condensation polymerization determines that the molecular weight distribution of synthetic polyurethane is generally wide, above 2. The low molecular weight part of synthetic polyurethane leads to poor physical and mechanical properties of materials, especially heart materials or blood vessel materials prepared from polyurethane, which are p...

AI Technical Summary

Problems solved by technology

This process is used for the classification of polymers such as polyvinyl chloride and polyisobutylene, but it is not suitable for the classification of polymers with high adhesion such as polyurethane

[0006] In the above-mentioned device, the feed port of the polymer solution is fixed. In order to ensure the industrial-scale separation, the diameter of this port is very large. When the polymer solution contacts the precipitant, the polymer solution with different molecular weights cannot be dispersed in time, resulting in Polymer-rich solution phase too large for poor separation

In addition, it is easy to cause the polymer to adhere to the inner wall of the equipment, especially the continuous grading of polyurethane

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