Para-aramid paper and preparation method thereof

Abstract

The invention provides a preparation method of para-aramid paper. The preparation method comprises the steps as follows: carrying out top wire forming on para-aramid nanofiber material liquid to obtain wet paper; carrying out multi-stage buffer squeezing dewatering on the wet paper to obtain dewatered wet paper; and sequentially carrying out multi-stage low-temperature drying and tension-assisteddrying and forming on the dewatered wet paper to obtain the para-aramid paper. The top wire forming method comprises the steps as follows: after carrying out sizing on the para-aramid nanofiber material liquid, carrying out drainage, and forming a wet paper blank on the surface of a forming wire; and carrying out bidirectional dewatering in a combined mode of carrying out vacuum suction on the lower surface of the wet paper blank and then carrying out dewatering on the upper surface of the wet paper blank by a top wire former, so as to obtain the wet paper. According to the invention, the aramid paper which is good in uniformity and excellent in mechanical property and insulation property can be prepared by adopting the special top wire forming process, the multi-stage buffer squeezing process, the multi-stage low-temperature drying process and the tension-assisted drying process. The invention further provides para-aramid paper.

Description

technical field [0001] The invention relates to the technical field of film materials, in particular to a para-aramid paper and a preparation method thereof. Background technique [0002] Para-aramid paper (PAP) is a high-performance special film material, which has the advantages of high strength and high modulus, excellent dimensional stability, excellent electrical insulation performance, chemical corrosion resistance, and light weight. It can be used as structural materials, insulating materials , wave penetration and filter materials are widely used in aerospace, military equipment, electronic appliances and other industries. [0003] At present, the raw materials used to prepare PAP are mainly para-aramid short fibers, pulp or precipitated fibers, and sometimes meta-aramid fibers or other thermoplastic resins are added as reinforcing agents. The process of papermaking is also relatively complicated. Generally, the fiber needs to be beaten into a slurry through a speci...

AI Technical Summary

Problems solved by technology

Even so, it is difficult to prepare stable PAP

Because the thickness of PAP is generally tens of microns (the thickness of some PAPs for special purposes is more than 100 microns), while the diameter of para-aramid short fibers is about 10 microns, and the main structural size of pulp and precipitated fibers is also several hundred nanometers Once the slurry is dispersed unevenly, it will easily cause the unevenness of PAP, and then make the performance of PAP unstable.

In addition, the addition of meta-aramid fibers and dispersing aids will also deteriorate the performance of PAP

Meta-aramid fiber has high hygroscopicity, which will cause the dimensional stability of PAP to decrease under high humidity, and it is difficult to meet the requirements of high-precision products

The addition of dispersant, on the one hand, is not conducive to the dielectric properties of PAP, on the other hand, it will also generate a large amount of waste water, resulting in environmental pollution or increased production costs.

[0004] Moreover, in the papermaking process of using all-nanofibers, there are difficulties in dehydration, low wet strength of the prepared wet paper, and large dimensional shrinkage during the drying process, which seriously affects the performance of the prepared para-aramid paper.