Polyester fiber, process for the production and process for the dyeing of the fibrous structure of the polyester fiber

Abstract

A fiber of a polyester, in which 80% or more of the repeating units are composed of ethylene terephthalate, characterized in that it satisfies the following inequalities: 0.16<tan .delta..sub.max <0.22 1 115<T.sub.max <140 2 D.sub.100 <-3.79.times.d.sup.1/2 +91 3 D.sub.130 >-11.36.times.d.sup.1/2 +58 4 as well as a process for the production and dyeing of a fibrous structure of the polyester fiber. According to the present invention, especially in deep color dyeing at a high temperature, the degree of dye exhaustion is improved, and the utilization efficiency of the dye is enhanced, and moreover, especially in an extremely fine fiber yarn, a polyester fibrous structure having a concentration of a color shade equal to that of an ordinary yarn, which has never been obtained by the conventional process can be provided. In addition, there can be provided a polyester fiber and a fibrous structure thereof that are excellent in coloring properties and color fastness and can be used for various purposes.

Dependencies are inferred from the claim text.