Method for preparing high-modulus para-aramid fibers

Abstract

The invention discloses a method for preparing high-modulus para-aramid fibers, and belongs to the technical field of artificial fibers.The method includes steps of dissolving poly-p-phenylene terephthamide resin in concentrated sulfuric acid, stirring the poly-p-phenylene terephthamide resin under a heating condition to obtain spinning solution, ejecting the spinning solution from a spinneret plate of a spinning tank by the aid of a dry-jet wet-spinning process, feeding the spinning solution into coagulation bath via air layers to form fiber strands, and sequentially washing and neutralizing the fiber strands; drying the obtained wet fiber strands under the effect of tension by the aid of a pre-drying device in a gradient heating mode and removing water on the surfaces of the wet fiber strands; discharging the pre-dried fiber strands out of the pre-drying device and simultaneously oiling the pre-dried fiber strands; carrying out heat-stretching on the fiber strands to be subjected to heat-stretching; carrying out heat-setting on the fiber strands to be subjected to heat-setting, discharging the fiber strands out of heat-setting rolls, oiling the fiber strands again and cooling the fiber strands to obtain finished products.The method has the advantages that the problem of excessive broken filaments due to excessively high tension can be solved; broken filaments can be prevented; the high-modulus para-aramid fibers obtained by the aid of the method are high in strength and modulus.

Description

technical field [0001] The invention belongs to the technical field of man-made fibers, and in particular relates to a preparation method of high-modulus para-aramid fibers. Background technique [0002] The chemical name of para-aramid fiber is polyparaphenylene terephthalamide fiber (PPTA fiber), which is formed by dissolving polyparaphenylene terephthalamide polymer powder in concentrated sulfuric acid to form anisotropic And the spinning solution with liquid crystal behavior is sprayed out from the spinneret by the spinning method of dry jet wet spinning, and then coagulated into fiber tow in a special coagulation device with dilute sulfuric acid as a coagulation bath, and then washed, neutralized Blending, drying, stretching or setting, and then oiling and winding to form finished fibers, which are high-strength, high-modulus and high-temperature-resistant fibers. Such as US Patent US3767756 and World Patent WO9634732 all describe the preparation method of this type of...

AI Technical Summary

Problems solved by technology

But at the same time, due to such a structure, the fiber is prone to fibrillation. Under friction and high tension, the surface of the fiber is easy to fluff and form wool, resulting in a decline in product quality and even failure to wind normally.

[0010] From the above description, we can know how to find a reasonable balance point between tension and temperature in the heat stretching and heat setting after the wet fiber tow is dried, so as to avoid the generation of fuzz, and how to control the fiber fibrillation that is Obtaining high-strength and high-modulus para-aramid fibers while controlling the generation of fuzz has become a technical problem that the industry pays attention to and expects to solve, but it has not been found in the disclosed patent documents and non-patent documents that are not limited to the above examples. All technical inspirations that can be used for reference