Method for manufacturing polyisophthaloyl metaphenylene diamide pulp-shaped fibre

Abstract

The invention relates to a method for preparing polyisophthaloyl metaphenylene diamide pulp-shaped fiber belonging to the special synthesis fiber preparation technique field, which is characterized in that the polyisophthaloyl metaphenylene diamide solution is mixed with a precipitant in a shaping equipment which rotates at certain speed, the polyisophthaloyl metaphenylene diamide solution dissolves out the pulp-shaped fiber in the shearing condition through the precipitant directly. The component of the precipitant contains organic solvent which is provided with high-apparent viscosity for adjusting the apparent viscosity of the precipitant, thereby the pulp-shaped fiber of different long diameter ratio is obtained to satisfy different application need of the product. The viscosity ratio of the precipitant and the pulp is enlarged and the force between the pulp and the precipitant is strengthened due to increasing the apparent viscosity of the precipitant, thereby the superior property pulp-shaped fiber can be obtained in the relatively low stirring rotary speed condition of the shaping equipment.

Description

technical field [0001] The invention relates to a preparation method of polym-phenylene isophthalamide pulp-like fiber, which belongs to a non-spinning direct fiber-forming method. Background technique [0002] Poly-m-phenylene isophthalamide paper (commonly known as aramid paper in China) is an indispensable raw material for national defense industry and civilian industry. This paper has high strength, good toughness, large dielectric constant, and can withstand high temperature for a long time. Features used. The honeycomb material made of this kind of paper has become an ideal material for large rigid and light-weight structural parts due to its light weight, easy processing and high performance, such as manufacturing fighter jets and high-speed passenger cars. Because this kind of paper has excellent high temperature resistance and good insulation (H grade), it can also be used as insulating paper for high-grade motors and as a high-performance printed circuit substrate...

AI Technical Summary

Problems solved by technology

The precipitation solvent is a mixture of DMAc and polar solvents. The preparation of the aramid stock solution used in this method requires secondary polymerization. The production process is long and the process is complicated. At the same time, the specific surface area of ​​the product precipitation fiber is relatively small, which is not conducive to obtaining High quality aramid paper

[0005] U.S. Patent No. 5,723,568 discloses a method for producing fine fibers and paper-like sheets of aliphatic or aromatic polyamides. It is made with water as a precipitating agent in a settling device. The fine fibers obtained can be mixed with natural pulp or Other synthetic fibers are mixed to prepare synthetic fiber paper. This patent has no requirements for key indicators such as the molecular weight of raw materials for preparing fibrids. At the same time, it also has no requirements for the key factors of shear forming in the process of precipitating manufacturing—coagulation bath viscosity, shear rate, etc. There are no strict restrictions, so the quality of the precipitated fiber produced fluctuates greatly, which is not conducive to obtaining aramid paper with stable performance