PURPOSE: To obtain the title new yarn having excellent devitrification resistance by delivering spinning dope comprising a polymer composed of acrylonitrile, vinylidene chloride and sulfonic acid-containing monomer, etc., into a gas, introducing into a coagulating bath, primarily drawing yarn in hot water and secondarily drawing under dry heat.
CONSTITUTION: A polymer composed of 45-66wt.% acrylonitrile, 30-50wt.% vinylidene chloride, 0.5-4wt.% sulfonic acid-containing monomer (e.g. allylsulfonic acid) and 0-8wt.% another monomer [e.g. (meth)acrylic acid] copolymerizable with these monomers is dissolved in an organic solvent (e.g. DMF) to give spinning dope, which is delivered from a spinneret into a non-coagulating gas and introduced into a coagulating bath having 40-60% organic solvent concentration to form yarn. Then the yarn is primarily drawn in hot water at 60-100°C at ≥ twice draw ratio, the solvent is removed and the yarn is secondarily drawn under dry heat at ≤2.5 times draw ratio to give the objective yarn having ≥60% light transmittance after boiling water treatment, etc.
NISHIMURA KAZUO
TABUCHI TAKU
HOSAKO YOSHIHIKO
