Patent ID: 6569987
Filing Date: 2003-05-27
Classification: D01F

Abstract:
A process for producing meta aramid filaments by preparing a polymer solution of a meta aramid by a solution polymerization method and producing meta aramid filaments from the polymer solution, which process comprises a series of steps(1) to (7) of:(1) a polymerization step in which a meta aramid is prepared by reacting a aromatic meta-diamine with a aromatic meta-dicarboxylic acid chloride in a polar organic solvent; (2) a neutralization step in which hydrogen chloride contained in the polymer solution obtained in the polymerization step (1) is neutralized with a neutralizing agent comprising at least one member selected from the group consisting of sodium hydroxide and potassium hydroxide which form a salt insoluble in the polymerization solvent when reacted with the hydrogen chloride; (3) a filtering step in which the salt deposited from the polymer solution in the neutralization step (2) is removed by filtration; (4) a spinning solution-preparation step in which the polymer solution obtained in the filtering step (3) is mixed with water and a polar organic amide solvent, to provide a spinning solution; (5) a coagulation step in which the meta aramid-spinning solution obtained in the spinning solution-preparation step (4) is directly extruded in filamentary streams into an aqueous coagulation liquid to coagulate the extruded spinning solution streams into the form of filaments; (6) a water-washing step in which the filaments delivered from the coagulation step (5) are immersed in water to remove the salts and the solvent from the filaments; and (7) drawing and heat-treatment steps in which the filaments delivered from the water-washing step (6) are drawn and heat-treated.