Method for preparing polyisophthaloyl metaphenylene diamine solution without metal ions

Abstract

The invention relates to a method for preparing a polyisophthaloyl metaphenylene diamine solution without metal ions. The method is characterized by comprising the following steps: (1) dissolving certain moles of m-phenylenediamine into an amide polar organic solution, and reducing the temperature of the system to be minus 10-20 DEG C; (2) adding isophthaloyl dichloride (80-95% of the equal mole ratio) which is less than the mole ratio into the system, performing condensation polymerization for 10-30 minutes, subsequently adding the rest isophthaloyl dichloride to stir and reacting for 0.5-1 hour to accomplish the condensation polymerization reaction; and (3) adding ammonia water into a polymerized solution after the ammonium hydroxide reaction, neutralizing hydrogen chloride generated in the reaction, and filtering to remove ammonium chloride so as to prepare a polyisophthaloyl metaphenylene diamine spinning solution. As isophthaloyl dichloride is added twice, the reaction heat released from polymerization is reduced, the acidity is reduced through filtration, the degradation function of a polymer is alleviated, the energy consumption is reduced, and no metal ions are introduced in the neutralization reaction, so that the prepared spinning solution is free of the metal ions, and the requirements of industrial large-scale production of aramid fiber insulting paper are met.

Description

technical field [0001] The invention relates to a method for preparing a metal ion-free polym-phenylene isophthalamide solution, specifically, a three-step method for preparing a metal ion-free polym-phenylene isophthalamide solution Methods. Background technique [0002] Poly-m-phenylene isophthalamide fiber is called meta-aramid fiber or aramid fiber 1313 (PMIA). It is the organic high-performance fiber with the earliest development, the largest output and the widest application. It is the most high-temperature resistant fiber in the world today. One of the best high-tech new materials, known as "fireproof fiber", is a high-quality functional fiber. [0003] The unique and stable chemical structure endows aramid fiber 1313 with excellent performance. Through the comprehensive utilization of these characteristics, a series of new functions and new products are continuously developed. Lun 1313 has become an irreplaceable material for some special supplies, such as gloves a...

AI Technical Summary

Problems solved by technology

[0006] Chinese patent CN201110406292.5 relates to a method for preparing polym-phenylene isophthalamide spinning solution by continuous low-temperature polymerization, including two steps: 1) m-phenylene diamine and isophthaloyl chloride in amide Low-temperature polymerization in a polar organic solvent; 2) The hydrogen chloride generated by the reaction is neutralized with calcium hydroxide. Its advantage is continuous polymerization. Although it can be directly spun, it also brings in metal ions during polymerization neutralization. There are also defects that reduce the insulation of aramid paper

Specifically, first pre-polymerize m-phenylenediamine and isophthaloyl chloride in an equimolar ratio, pre-neutralize with liquid ammonia, filter to remove salt, and filter the prepolymer with the remaining isophthaloyl chloride Polymerize in a twin-screw, then neutralize with calcium hydroxide, and the resulting polymer is directly used for spinning. This method involves many steps and requires two polymerization tanks. The cost is high and the production efficiency is low, which is not conducive to large-scale industrial production. , similarly, metal ions are also artificially introduced during the neutralization reaction

[0008] The polym-phenylene isophthalamide solution prepared by the current polymerization method contains metal ions, which reduces the insulation of aramid paper