| 摘要 |
PROBLEM TO BE SOLVED: To produce a polyester thick and thin fiber, excellent in dry touch feeling and drapeability and useful for a knitted or a woven fabric, etc., by treating a specific undrawn fiber under specified conditions. SOLUTION: An undrawn fiber which is a polyester fiber, comprising ethylene terephthalate as a main recurring unit and obtained by melt spinning a polyester containing 0.5-5wt.% metallic salt of an organic sulfonic acid represented by the formula, R-SO3 M (R is a 3-30C alkyl, a 7-40C aryl, etc.; M is an alkali metal) at <=3,500m/min is drawn and heat-treated under conditions satisfying formulae I to V [TDR is the total draw ratio; MDR is the maximum draw ratio of the undrawn fiber; DR1 is the draw ratio in the first stage; DR2 is the draw ratio in the second stage; HRT is the temperature ( deg.C) in the drawing zone in the first stage; HPT in the temperature ( deg.C) in the drawing zone in the second stage; Tc is the crystallizing temperature ( deg.C) of the undrawn fiber; Tg is the glass transition point ( deg.C) of the undrawn fiber] to form a thick and thin fiber. The weight reduction treatment of the resultant fiber is carried out in an aqueous solution of an alkali at >=5wt.% weight reduction ratio. Thereby, streaky grooves, having 0.1/5μm width, >=10μm length and <=5μm interval between the adjacent streaky grooves and oriented in the fiber axial direction are formed on the thick part surface. |
