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.

What is claimed is: 
     
         1 - 28 . (canceled) 
     
     
         29 . A winged fiber comprising:
 an internal fiber having a cross-section and comprising a middle region, the middle region having between 16 projections and 32 projections extending from the middle region and along a periphery of the middle region;   wherein, the winged fiber has a denier in the range of 1-20 and a specific surface area between 28,000 cm 2 /g and 1,000,000 cm 2 /g.   
     
     
         30 . The winged fiber according to  claim 29  wherein the internal fiber comprises at least one thermoplastic polymer. 
     
     
         31 . The winged fiber according to  claim 29  wherein the middle region is hollow forming a hub with the projections extending outwardly therefrom. 
     
     
         32 . The winged fiber according to  claim 29  wherein the projections define channels between the projections, and wherein the channels have a channel width of between 200 nanometers and 1000 nanometers. 
     
     
         33 . The winged fiber according to  claim 29  wherein the winged fiber has a cross-sectional length of between 10 micrometers and 50 micrometers and a cross-sectional width between 5 micrometers and 50 micrometers and a shape factor of at least 10. 
     
     
         34 . The winged fiber according to  claim 29  wherein the winged fiber further comprises an external sheath, wherein the external sheath encompasses the internal fiber, and wherein the external sheath is dissolvable. 
     
     
         35 . A winged fiber comprising:
 an internal fiber having a cross-section comprising a middle region, the middle region having between 16 projections and 32 projections extending from the middle region and along a periphery of the middle region;   wherein, the winged fiber has a cross-sectional length between 10 micrometers and 50 micrometers and a cross-sectional width between 5 micrometers and 50 micrometers and a specific surface area between 28,000 cm 2 /g and 1,000,000 cm 2 /g.   
     
     
         36 . The winged fiber according to  claim 35  wherein the internal fiber comprises at least one thermoplastic polymer. 
     
     
         37 . The winged fiber according to  claim 35  wherein the middle region is hollow forming a hub with the projections extending outwardly therefrom. 
     
     
         38 . The winged fiber according to  claim 35  wherein the projections define channels between the projections, and wherein the channels have a channel width of between 200 nanometers and 1000 nanometers. 
     
     
         39 . The winged fiber according to  claim 35  wherein the winged fiber has a denier in the range of 1-20. 
     
     
         40 . The winged fiber according to  claim 35  wherein the winged fiber has a cross-sectional length of between 10 micrometers and 50 micrometers and a cross-sectional width between 5 micrometers and 50 micrometers and a shape factor of at least 10. 
     
     
         41 . The winged fiber according to  claim 35  wherein the winged fiber further comprises an external sheath, wherein the external sheath encompasses the internal fiber, and wherein the external sheath is dissolvable. 
     
     
         42 . A winged fiber comprising:
 an internal fiber having a cross-section comprising a middle region, the middle region having between 16 projections and 32 projections extending from the middle region and along a periphery of the middle region;   wherein, the winged fiber has a cross-sectional length of between 10 micrometers and 50 micrometers and a cross-sectional width between 5 micrometers and 50 micrometers and a shape factor of at least 10.   
     
     
         43 . The winged fiber according to  claim 42  wherein the internal fiber comprises at least one thermoplastic polymer. 
     
     
         44 . The winged fiber according to  claim 42  wherein the middle region is hollow forming a hub with the projections extending outwardly therefrom. 
     
     
         45 . The winged fiber according to  claim 42  wherein the projections define channels between the projections, and wherein the channels have a channel width of between 200 nanometers and 1000 nanometers. 
     
     
         46 . The winged fiber according to  claim 42  wherein the winged fiber has a denier in the range of 1-20 and a specific surface area between 28,000 cm 2 /g and 1,000,000 cm 2 /g. 
     
     
         47 . The winged fiber according to  claim 42  wherein the winged fiber further comprises an external sheath, wherein the external sheath encompasses the internal fiber, and wherein the external sheath is dissolvable. 
     
     
         48 . A winged-fiber, the cross-section of the fiber comprising:
 a middle region having between 16 projections and 32 projections and between 16 channels and 32 channels; wherein the projections extend from the middle region along the periphery of the middle region; and   wherein the projections define the channels, and wherein the channels have a channel width of between 200 nanometers and 1000 nanometers.   
     
     
         49 . The winged fiber according to  claim 48  wherein the middle region comprises at least one thermoplastic polymer. 
     
     
         50 . The winged fiber according to  claim 48  wherein the middle region is hollow forming a hub with the projections extending outwardly therefrom. 
     
     
         51 . The winged fiber according to  claim 48  wherein the winged fiber has a cross-sectional length of between 10 micrometers and 50 micrometers and a cross-sectional width between 5 micrometers and 50 micrometers and a shape factor of at least 10. 
     
     
         52 . The winged fiber according to  claim 48  wherein the winged fiber has a denier in the range of 1-20 and a specific surface area between 28,000 cm 2 /g and 1,000,000 cm 2 /g. 
     
     
         53 . The winged fiber according to  claim 48  wherein the winged fiber further comprises an external sheath, wherein the external sheath encompasses the middle region, and wherein the external sheath is dissolvable.