Manufacturing method of fine hollow polyester filaments, fine hollow polyester filaments made from the same and fine hollow polyester yarns

Abstract

Disclosed is to provide a manufacturing method for fine hollow polyester filaments. The length of a protective delay shroud of the radial outer-flow quenching system used in melt spinning process for manufacturing fine hollow polyester filaments is expressed as (2˜8060×throughput÷filaments square), and the length of quenching air tube is from 15 to 40 centimeters. The velocity of quenching air is between 0.2 m/sec to 0.6 m/sec. For the layout of the spinneret orifices, the diameter difference of outermost layer orifice and the innermost layer orifice is set less than 20 mm; and the distance between the diameter of innermost orifice layout and the diameter of quenching air tube is at least 12 and less than 33 mm. The orifice density of spinneret layout (orifice density) is set as 7˜15 orifices per square centimeter. The fine hollow polyester filaments produced in this invention has 0.3 to 2.5 denier per filament (d.p.f), uster half inert value (u % 1/2 inert) less than 0.3%, variation of thermal stress in spindles less than 4%, hollow degree from 25 to 40%, after draw texturing process, fine hollow polyester yarn having d.p.f 0.2 to 1.0d, hollow degree 25 to 40% in excellent dyeability can be obtained.

What is claimed is:  
     
         1 . A manufacturing method for fine hollow polyester filaments, which is heating polyester polymer of inherent viscosity(IV) 0.5˜0.7 and melting point of 245˜265° C. to melt, filter and extruding in constant amount to obtain polyester fine hollow filaments, characterized in comprising the following steps: 
 a. uniformly spinning said constant amount extruded polyester melt through a multi-layer annularly arranged spinneret orifices to obtain the filament tow, wherein the diameter of outermost layer orifice is set as D 2  mm, and the diameter of innermost layer orifice is set as D 1  mm;  
 b. passing said spun filament tow under spinneret through a protective delay shroud of length L s  mm and a cylindrical quenching air tube of length L q  mm and diameter of D 0  mm which offers the radial outer-flow quenching air at wind speed of 0.2-0.6 meter/second to said filament tow from the outer side of said cylindrical quenching air tube to uniformly cooled to below glass transition point (T g ) of said polyester polymer for bundling;  
 c. said D 2 , D 1 , D 0 , L s , L q  satisfying the following requirements: 
 (i) D 2 −D 1 ≦20 (mm)  
 (ii) 12≦D 1 −D 0 ≦33 (mm)  
 (iii) 2≦Ls≦8060×throughput (g/min)÷(No. of filaments) 2  (mm)  
 (iv) 15≦Lq≦40(cm)  
 
 d. winding said filament tow at the speed of 1800 to 4000 meter/minute.  
 
     
     
         2 . The manufacturing method for fine hollow polyester filaments according to  claim 1 , wherein, the orifice density of spinneret layout (orifice density) is set as 7˜15 orifices per square centimeter.  
     
     
         3 . The manufacturing method for fine hollow polyester filaments according to  claim 1 , wherein, the fine hollow polyester filaments obtained has 0.3 to 2.5 denier per filament (d.p.f), uster half inert value (u %  1/2  inert) less than 0.3%, variation of thermal stress in spindles less than 4%, hollow degree from 25 to 40%.  
     
     
         4 . A fine hollow polyester yarn, which is produced by draw-twist texturing, air -twist texturing or one-stage direct spinning and drawing the filaments manufactured by the manufacturing method for fine hollow polyester filaments according to  claim 1  to get fine hollow polyester yarn having d.p.f 0.2 to 1.0 d, hollow degree 25 to 40% in excellent dyeability and flat surface of fabrics woven or knitted from said yarn.