Process to manufacture a spun-dyed para-aramid filament yarn and sliver
Abstract:
Manufacturing a spun-dyed para-aramid filament yarn includes (a) preparing a spin dope comprising a para-aramid polymer, at least one dyestuff and concentrated sulfuric acid, (b) spinning the spin dope through a spinneret to obtain spun filaments, (c) coagulating the spun filaments to obtain coagulated filaments, (d) neutralizing the coagulated filaments to obtain neutralized filaments, (e) washing the neutralized filaments to obtain washed filaments, and (f) drying the washed filaments to obtain dried filaments. In step a) the spin dope includes 17.5 to 18.5% by weight of a para-aramid polymer with respect to the weight of the spin dope, and 4 to 15% by weight of the at least one dyestuff with respect to the weight of the para-aramid polymer plus the at least one dyestuff. In step f) the filaments are hold under a tension in a range from 0.2 to 0.8 cN/dtex.
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