| abstract |
(57) [Abstract] [Purpose] To provide a polyester fiber for industrial use, which has no change in color tone over time, suppresses abnormal dyeing during dyeing, and has good storage stability. [Structure] As a leveling agent, a polyvalent ester compound of a polyhydric alcohol and a carboxylic acid compound having a valence of 1 or more and / or 1 A polyester fiber for industrial use, which is provided with an oil agent composition containing a polyvalent ester compound of a polyhydric alcohol and a polyvalent carboxylic acid and simultaneously containing the compounds of the following (a) and (b). (A) Pentaerythritol tetrakis (lauryl thiopropionate) (b) 1,3,5-Tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate |