PURPOSE: To provide the subject polyester fiber excellent in the color-generating property and in the color brilliancy when the fiber is dyed.
CONSTITUTION: This deeply dyeable polyester fiber comprises a highly oriented and non-drawn fiber having a modified cross section, and has (a) an amorphous orientation rate of 0.03-0.10, (b) a crystal size of ≥4,5nm, (c) a modification degree of ≥1.2, (d) a projection number of ≥5 on the cross section and (e) a surface area ratio of ≥1.3. Since the crosssectional shape of the fiber is the specific modified crosssectional one, the orientation in the amorphous parts of the fiber is lowered to improve the color-developing property and the coloring rate, and the reflection of light on the surface of the fiber is reduced to enhance the brilliancy of the fiber and remove the irregular feeling.
TANIGUCHI KATSUTOSHI
NAGAI HIROYUKI
