Preparation method of poly (p-phenylene terephthamide) spinning solution

Abstract

The invention relates to a preparation method of a poly (p-phenylene terephthamide) spinning solution. The preparation method comprises the steps that vacuum drying and freezing treatment are conducted on poly (p-phenylene terephthamide), and treated poly (p-phenylene terephthamide) is obtained; concentrated sulfuric acid is cooled, solidified and smashed; the treated poly (p-phenylene terephthamide) and treated concentrated sulfuric acid are mixed at a low temperature to obtain a solid solution, a vacuum condition is created, and the solid solution is heated up and dissolved to form the spinning solution. According to the preparation method of the poly (p-phenylene terephthamide) spinning solution, two powdered substances are fully mixed, the mixing efficiency is high, and the dissolving time is greatly reduced; the vacuum condition is created before the dissolving process is conducted, bubbles are not produced in the solution, the deaeration process is omitted, and degradation of the polymer is greatly slowed down; the whole dissolving process is simple and easy to carry out, and the industrial production of high-quality poly (p-phenylene terephthamide) fibers is facilitated.

Description

technical field [0001] The invention belongs to the field of preparation of spinning stock solution, in particular to a preparation method of poly-p-phenylene terephthalamide. Background technique [0002] Polyparaphenylene terephthalamide fiber is called para-aramid fiber or aramid fiber 1414 (PPTA), which has excellent properties such as high strength, high modulus, resistance to organic solvents, and light weight. The strength is 5-6 times that of high-quality steel. times, the modulus is 2-3 times that of steel and glass fiber, and the density is only 1 / 5 of that of steel. Therefore, the fiber spun has the reputation of "artificial steel wire", and is widely used in national defense, armor and aviation. Aerospace and other special fields. [0003] Due to its broad application background, countries with technology, such as the United States and Japan, strictly block their technology, while non-owner countries are developing production technologies that can be industriali...

AI Technical Summary

Problems solved by technology

[0004] The preparation of para-aramid spinning stock solution is an important part of large-scale industrialization. Chinese patent CN102268743 provides a preparation technology of para-aramid spinning solution. Formamide p-phenylenediamine resin is mixed and dissolved in a twin-screw extruder to obtain an efficient and uniform solution. The disadvantage is that the introduction of co-solvent perchloric acid increases the chlorine content in the spun fibers, which is far more than that of European counterparts. Aramid fiber chlorine content standard

Chinese patent CN1256474 relates to the manufacture method of poly-p-phenylene terephthalamide fiber, wherein, the preparation of spinning solution is provided, the method is to mix PPTA with sulfuric acid with a concentration greater than 99%, and enter it in a twin-screw extruder Dissolving and defoaming, this method of preparing spinning solution, the water brought in by impure sulfuric acid will make it difficult to dissolve and lead to the degradation of PPTA

This solid-liquid dissolution method itself takes a long time to dissolve, and in the air, stirring will cause the solution to generate a large number of bubbles, and it will take a long time to defoam, which will lead to polymer degradation and also cause polymer degradation.

Solid-liquid two-phase mixing, the solution may also produce inhomogeneity