High melting point resin fibers and nonwoven fabric

Abstract

Provided are: a high-melting-point resin fiber having heat resistance and solvent resistance, offering excellent workability/formability, and having a diameter of 4 μm or less; and a nonwoven fabric including the high-melting-point resin fiber. Also provided is a method for efficiently producing a high-melting-point resin fiber having a diameter of 4 μm or less, via laser melt electrospinning. The high-melting-point resin fiber according to the present invention includes a resin having a melting point of 250° C. or higher and has a diameter of 4 μm or less. In the high-melting-point resin fiber, the resin having a melting point of 250° C. or higher is preferably a PEEK. The fiber preferably has a degree of crystallinity of 30% or less.

1 . A high-melting-point resin fiber comprising
 a resin having a melting point of 250° C. or higher,   the fiber having a diameter of 4 μm or less.   
     
     
         2 . The high-melting-point resin fiber according to  claim 1 ,
 wherein the resin having a melting point of 250° C. or higher comprises a poly(ether ether ketone) (PEEK).   
     
     
         3 . The high-melting-point resin fiber according to  claim 1 ,
 which has a degree of crystallinity of 30% or less.   
     
     
         4 . A method for producing a high-melting-point resin fiber, the method comprising:
 applying planar laser light to a polymer sheet comprising a noncrystalline high-melting-point resin to heat and melt an edge of the polymer sheet linearly to thereby form a band-like molten zone;   providing a potential difference between the band-like molten zone and a fiber collecting plate to form a needle protrusion in the band-like molten zone of the polymer sheet and to allow a fiber ejected from the needle protrusion to fly toward the fiber collecting plate; and   collecting the fiber on the fiber collecting plate or on a collector disposed between the molten zone and the fiber collecting plate to give the high-melting-point resin fiber according to  claim 1 .   
     
     
         5 . The method according to  claim 4  for producing a high-melting-point resin fiber,
 wherein the polymer sheet is fed at a speed of 2 to 20 mm/min. 
 
     
     
         6 . The method according to  claim 4  for producing a high-melting-point resin fiber,
 wherein the potential difference is 0.1 to 30 kV/cm. 
 
     
     
         7 . The method according to  claim 4  for producing a high-melting-point resin fiber,
 wherein the polymer sheet has a viscosity of 800 Pa·s or less as measured at a temperature of 400° C. and a shear rate of 121.6 s −1 . 
 
     
     
         8 . A nonwoven fabric comprising
 the high-melting-point resin fiber according to  claim 1 .   
     
     
         9 . The high-melting-point resin fiber according to  claim 2 ,
 which has a degree of crystallinity of 30% or less.   
     
     
         10 . A method for producing a high-melting-point resin fiber, the method comprising:
 applying planar laser light to a polymer sheet comprising a noncrystalline high-melting-point resin to heat and melt an edge of the polymer sheet linearly to thereby form a band-like molten zone;   providing a potential difference between the band-like molten zone and a fiber collecting plate to form a needle protrusion in the band-like molten zone of the polymer sheet and to allow a fiber ejected from the needle protrusion to fly toward the fiber collecting plate; and   collecting the fiber on the fiber collecting plate or on a collector disposed between the molten zone and the fiber collecting plate to give the high-melting-point resin fiber according to  claim 2 .   
     
     
         11 . A method for producing a high-melting-point resin fiber, the method comprising:
 applying planar laser light to a polymer sheet comprising a noncrystalline high-melting-point resin to heat and melt an edge of the polymer sheet linearly to thereby form a band-like molten zone;   providing a potential difference between the band-like molten zone and a fiber collecting plate to form a needle protrusion in the band-like molten zone of the polymer sheet and to allow a fiber ejected from the needle protrusion to fly toward the fiber collecting plate; and   collecting the fiber on the fiber collecting plate or on a collector disposed between the molten zone and the fiber collecting plate to give the high-melting-point resin fiber according to  claim 3 .   
     
     
         12 . The method according to  claim 5  for producing a high-melting-point resin fiber, wherein the potential difference is 0.1 to 30 kV/cm. 
     
     
         13 . The method according to  claim 5  for producing a high-melting-point resin fiber,
 wherein the polymer sheet has a viscosity of 800 Pa·s or less as measured at a temperature of 400° C. and a shear rate of 121.6 s −1 . 
 
     
     
         14 . The method according to  claim 6  for producing a high-melting-point resin fiber,
 wherein the polymer sheet has a viscosity of 800 Pa·s or less as measured at a temperature of 400° C. and a shear rate of 121.6 s −1 . 
 
     
     
         15 . A nonwoven fabric comprising
 the high-melting-point resin fiber according to  claim 2 .   
     
     
         16 . A nonwoven fabric comprising
 the high-melting-point resin fiber according to  claim 3 .