Production processes of polyester filaments for moisture wicking

Abstract

The process of the present invention may be used to produce polyester filaments that exhibit superior moisture and perspiration absorption. In various embodiments, this process involves: (1) pre-crystallizing polyester chips in a crystallizer; (2) drying and ventilating the polyester chips after crystallization to produce dried polyester chips; (3) melting the dried polyester chips in a screw extruder; (4) filter the melted polyester chips to form a filtered melt; (5) introducing the filtered melt into a spinning box via a metering pump, wherein the filtered melt enters the spinning assembly; (6) extruding the filaments from the spinning assembly; (7) cooling the extruded filaments from the spinning assembly to room temperature in order to solidify the filaments and form a fiber tow; and (8) winding the fiber tow via a winding machine to form a wound tow. The process described herein can produce polyester filaments that comprise a longitudinal groove along the surface of fiber, which can provide a capillary effect that enhances the moisture wicking capabilities of the filaments. Consequently, the polyester filaments of the present invention can be used to produce woven articles, such as reinforcement fabrics, that comprise fiber micro-grooves along the surface of the article, thereby enhancing the article's sweat wicking capabilities, water diffusion capabilities, and water transfer capabilities. Furthermore, the use of these grooved polyester filaments of the present invention can facilitate the migration of water and moisture to the surface of the fabric, thereby allowing the moisture to spread out on the surface and enabling it to quickly evaporate. Consequently, this can keep the skin of the wearer dry.

What is claimed is: 
     
         1 . A process for producing a wicking polyester filament, wherein the process comprises:
 (a) forming polyester chips in a crystallizer at a temperature of at least 120° C., wherein the forming occurs for not more than 30 minutes;   (b) drying the polyester chips to a water content of 20 to 50 ppm to form dried polyester chips;   (c) melting the dried polyester chips in an extruder at a temperature of at least 270° C. to form a polyester melt;   (d) filtering the polyester melt with a filter to form a filtered polyester melt;   (e) spinning the filtered polyester melt with a spinning pack to form extruded filaments, wherein the spinning pack comprises a head temperature of at least 280° C. and operates at a pressure in the range 100 to 170 kgf/cm 2 ; and   (f) cooling the extruded filaments with a gas stream to form a fiber tow.   
     
     
         2 . The process of  claim 1 , wherein the forming of step (a) occurs at a temperature in the range of 120 to 170° C. 
     
     
         3 . The process of  claim 2 , wherein the forming of step (a) occurs over a period of 20 to 30 minutes. 
     
     
         4 . The process of  claim 1 , wherein the melting of step (c) occurs at a temperature in the range of 270 to 295° C. 
     
     
         5 . The process of  claim 4 , wherein the filter in step (d) comprises a pore size in the range of 0.3 to 0.6 mm. 
     
     
         6 . The process of  claim 1 , wherein the spinning pack comprises a head temperature in the range of 280 to 300° C. 
     
     
         7 . The process of  claim 1 , wherein the gas stream is positioned to contact the extruded filaments at an angle ranging from 60 to 120 degrees during the cooling of step (f). 
     
     
         8 . The process of  claim 7 , wherein the gas stream is positioned to contact the extruded filaments at an angle of about 90 degrees during the cooling of step (f). 
     
     
         9 . The process of  claim 7 , wherein the gas stream is at a temperature in the range of 20 to 30° C. and flows at a rate in the range of 0.3 to 0.6 m/s. 
     
     
         10 . The process of  claim 1 , further comprising winding the fiber tow at a winding angle of 5 to 7 degrees with a winding machine to form a wound fiber. 
     
     
         11 . The process of  claim 1 , wherein the drying of step (b) occurs at a temperature in the range of 150 to 170° C. over a period of 4 to 8 hours. 
     
     
         12 . A process for producing a wicking polyester filament, wherein the process comprises:
 (a) forming polyester chips in a crystallizer at a temperature of at least 100° C.;   (b) drying the polyester chips to a water content of less than 200 ppm to form dried polyester chips;   (c) melting the dried polyester chips in an extruder at a temperature of at least 225° C. to form a polyester melt;   (d) filtering the polyester melt with a filter to form a filtered polyester melt;   (e) spinning the filtered polyester melt with spinning pack comprising a non-round shaped spinneret to form extruded filaments, wherein the spinning pack comprises a head temperature of at least 250° C. and operates at a pressure of at least 100 kgf/cm 2 ; and   (f) cooling the extruded filaments with a gas stream to form a fiber tow comprising a plurality of polyester filaments, wherein the polyester filaments comprise a lobed-shape cross section comprising a plurality of lobes.   
     
     
         13 . The process of  claim 12 , wherein the filaments comprise a transverse aspect ratio of at least 1.5. 
     
     
         14 . The process of  claim 12 , wherein the forming of step (a) occurs at a temperature in the range of 120 to 170° C. and over a period of 20 to 30 minutes. 
     
     
         15 . The process of  claim 12 , wherein the gas stream is positioned to contact the extruded filaments at an angle ranging from 60 to 120 degrees during the cooling of step (f). 
     
     
         16 . The process of  claim 15 , wherein the gas stream is at a temperature in the range of 20 to 30° C. and flows at a rate in the range of 0.3 to 0.6 m/s. 
     
     
         17 . The process of  claim 12 , further comprising winding the fiber tow at a winding angle of 5 to 7 degrees with a winding machine to form a wound fiber. 
     
     
         18 . A woven fabric comprising a polyester filament,
 wherein the polyester filament comprises a lobed-shape cross-section containing a plurality of lobes, and   wherein the woven fabric exhibits a vertical wicking height of at least 100 mm/10 minutes and a diffusion area of at least 1,700 mm 2 /30 seconds.   
     
     
         19 . The fabric of  claim 18 , wherein the polyester filament comprises 4 lobes. 
     
     
         20 . The fabric of  claim 18 , wherein the woven fabric exhibits a vertical wicking height of at least 75 mm/10 min and a diffusion area of at least 1,500 mm 2 /30 seconds.