| 摘要 |
PROBLEM TO BE SOLVED: To provide a fiber of fine size having dyeability including depth and clarity of dyeing and excellent texture with stable quality.SOLUTION: A polyester fiber is based on repeating units of ethylene terephthalate, consists of a single yarn of 0.1-1 dtex and is produced by a production process of esterifying a dicarboxylic acid ingredient based on terephthalic acid with a diol ingredient based on ethylene glycol and carrying out polycondensation of the oligomer. The polyester contains at least one metal compound selected from alkali metal and/or alkaline earth metal compounds and a phosphorus compound in amounts meeting the condition (1) 0.80<P/M≤2.0. The average length of concave parts, in the minor axis direction, of concavoconvex parts formed on the fiber surface is 0.1-1 μm; the average length in the longitudinal direction is 0.5-10 μm; and the number of concave parts per 10 μm is 5 or greater. |
