Method for spinning and winding pet filaments

Abstract

The present invention relates to a process for producing and winding POY filaments not less than 90% by weight PET, based on the total weight of the POY, at spinning takeoff speeds above 3 800 m/min, which comprises a) setting the spinline extension ratio in the range from 50 to 250, b) passing the filaments directly upon exit from the spinneret through a quench delay zone 20 mm to 300 mm in length, c) quenching the filaments to below the solidification temperature, d) converging the filaments at a distance between 500 mm and 2 500 mm from the underface of the spinneret, e) using at least one oiler pin per yarn to add spin finish to a standard deviation of less than 90 digits for the finish application variation, f) using oiler pins and yarn converging and yarn guiding elements that have low-friction surfaces, g) setting the yarn tension above the takeoff godets between 0.07 cN/dtex and 0.5 cN/dtex, h) entangling the yarn at a yarn tension between 0.05 cN/dtex and 0.20 cN/dtex and air pressure between 1.0 bar and 5.5 bar to a node count of at least 10 n/m with a coefficient of variation of less than 100%, i) winding the yarn at a yarn tension between 0.03 cN/dtex and 0.20 cN/dtex by driving the contact roll of the winder at an at least 0.3% higher frequency than the winding chuck and varying the angle of wind between a minimum of 3.5° and a maximum of 7.5° over the winding time.

What is claimed:  
     
         1 . A process for producing and winding POY filaments not less than 90% by weight PET, based on the total weight of the POY, at spinning takeoff speeds above 3 800 m/min, which comprises 
 a) setting the spinline extension ratio in the range from 50 to 250,    b) passing the filaments directly upon exit from the spinneret through a quench delay zone 20 mm to 300 mm in length,    c) quenching the filaments to below the solidification temperature,    d) converging the filaments at a distance between 500 mm and 2 500 mm from the underface of the spinneret,    e) using at least one oiler pin per yarn to add spin finish to a standard deviation of less than 90 digits for the finish application variation,    f) using oiler pins and yarn converging and yarn guiding elements that have low-friction surfaces,    g) setting the yam tension above the takeoff godets between 0.07 cN/dtex and 0.5 cN/dtex,    h) entangling the yarn at a yarn tension between 0.05 cN/dtex and 0.20 cN/dtex and air pressure between 1.0 bar and 5.5 bar to a node count of at least 10 n/m with a coefficient of variation of less than 100%,    i) winding the yarn up at a yarn tension between 0.03 cN/dtex and 0.20 cN/dtex by driving the contact roll of the winder at an at least 0.3% higher frequency than the winding chuck and varying the angle of wind between a minimum of 3.5° and a maximum of 7.5° over the winding time.    
     
     
         2 . A process as claimed in  claim 1 , wherein the spinning takeoff speed is in the range from 4 200 to 8 000 m/min, especially in the range from 4 600 to 6 000 m/min.  
     
     
         3 . A process as claimed in  claim 1  and/or  2 , wherein the PET used contains up to 2.5% by weight, based on the total weight of the filament, of additive polymer extensibility enhancer in admixture.  
     
     
         4 . A process as claimed in at least one of the preceding claims, wherein the filaments are cooled using a cooling means reducing stress-induced crystallization at high spinning speeds.  
     
     
         5 . A process as claimed in any of the preceding claims, wherein the PET used contains up to 2.5% by weight, based on the total weight of the filament, of additive polymer stretch enhancer in admixture and the filaments are cooled using a cooling means reducing stress-induced crystallization at high spinning speeds.