SPUN-DYED ULTRAFINE FIBER AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain an ultrafine fiber having a high strength in spite of a high content of carbon black and a deep color properties and to provide a method for producing the ultrafine fiber. SOLUTION: This ultrafine fiber is obtained by extracting and removing a dispersion medium component of a melt blend spun fiber comprising a dispersed component and the dispersing medium component, has <=0.6 dtex average single fiber fineness and comprises the carbon black having 10-50 nm average primary particle diameter and 30-600 cm3/100 g dibutyl phthalate(DBP) oil absorption volume in an amount of 1-30 wt.% based on the fiber weight. When the ultrafine fiber is produced, the volumes of both the resin pellets to be the dispersed component and the dispersion medium component are larger than the volume of master batch pellets containing the carbon black and melt blend spinning thereof is carried out.