Method and Apparatus for Making an Improved High Surface Area Fiber

Abstract

The present invention is directed to a high surface area fiber and method for making the same. The fiber includes a co-extruded internal fiber and an external sheath that is washed with a solvent to remove the dissolvable external sheath, the resulting fiber having a longitudinal axis and a cross-section, the cross-section having a middle region and projections extending from the middle region.

1 . A method of making a high surface area fiber, the method comprising:
 co-extruding an internal fiber and a dissolvable external sheath through at least one plate, then washing the co-extruded fibers with a solvent to remove the dissolvable external sheath, the resulting fiber having a longitudinal axis and a cross-section, the cross-section having a middle region and between 16 and 32 projections extending from the middle region.   
     
     
         2 . The method of  claim 1 , further comprising the step of melt spinning the internal fiber and the dissolvable external sheath to form a bicomponent fiber. 
     
     
         3 . The method of  claim 1 , further comprising the step of forming a textile product before washing to remove the dissolvable external sheath. 
     
     
         4 . The method of  claim 1 , further comprising the step of binding the high surface area fibers to form a non-woven fabric. 
     
     
         5 . The method of  claim 4 , wherein the step of binding the high surface area fibers to form a non-woven fabric further comprises binding using thermal, chemical, or mechanical means or a combination thereof 
     
     
         6 . The method of  claim 1 , further comprising binding the high surface area fibers to form a woven fabric. 
     
     
         7 . The method of  claim 1 , wherein the internal fiber has a specific surface area between 80,000 cm 2 /g and 1,000,000 cm 2 /g. 
     
     
         8 . The method of  claim 1 , wherein the internal fiber is a thermoplastic polymer. 
     
     
         9 . The method of  claim 1 , wherein the dissolvable external sheath is a dissolvable polymer. 
     
     
         10 . The method of  claim 9 , wherein the dissolvable polymer is polyactide (PLA). 
     
     
         11 . The method of  claim 9 , wherein the dissolvable polymer is polyvinyl alcohol (PVA). 
     
     
         12 . A winged fiber, the fiber comprising:
 a co-extruded fiber having an internal fiber and a dissolvable external sheath;
 the internal fiber having a longitudinal axis and a cross-section, the cross-section having a middle region and a plurality of projections extending from the middle region, the plurality of projections defining a plurality of channels, the channels having a width between 200 nanometers and 500 nanometers; and 
 the dissolvable external sheath being removed from the internal fiber by washing after the co-extrusion. 
   
     
     
         13 . The fiber of  claim 12 , wherein the internal fiber has a specific surface area between 80,000 cm 2 /g and 1,000,000 cm 2 /g. 
     
     
         14 . The fiber of  claim 12 , wherein the internal fiber is a thermoplastic polymer. 
     
     
         15 . The fiber of  claim 12 , wherein the dissolvable external sheath is a dissolvable polymer. 
     
     
         16 . The fiber of  claim 15 , wherein the dissolvable polymer is polyactide (PLA). 
     
     
         17 . The fiber of  claim 15 , wherein the dissolvable polymer is polyvinyl alcohol (PVA). 
     
     
         18 . A method of making a high surface area fiber, the method comprising:
 co-extruding a thermoplastic polymer internal fiber and a dissolvable external sheath through at least one plate, then washing the co-extruded fibers with a solvent to remove the dissolvable external sheath, the resulting fiber having a longitudinal axis and a cross-section, the cross-section having a middle region and a plurality of projections extending from the middle region, the plurality of projections defining a plurality of channels, the channels having a width between 200 nanometers and 500 nanometers.   
     
     
         19 . A method of making a high surface area fiber, the method comprising:
 co-extruding a thermoplastic polymer internal fiber and a dissolvable external sheath through at least one plate, then washing the co-extruded fibers with a solvent to remove the dissolvable external sheath, the resulting fiber having a longitudinal axis and a cross-section, the cross-section having a middle region and a plurality of projections extending from the middle region, and having a specific surface area of more than 80,000 square centimeters per gram.