Antibacterial nanofiber

Abstract

Disclosed is an antibacterial nanofiber which comprises a polymer having an electron-withdrawing group and/or an electron-withdrawing atomic group and has an average fiber diameter of not less than 1 nm and less than 1000 nm, wherein the ratio of the binding energy of the minimum unit of the polymer at 25° C. to the binding energy of the electron-withdrawing group and/or the electron-withdrawing atomic group contained in the minimum unit of the polymer at 25° C. is 0.13 or greater. The nanofiber has an antibacterial activity by itself, and therefore can exhibit an antibacterial activity without the need of adding any antibacterial agent.

1 . An antibacterial nanofiber comprising a polymer possessing electron-withdrawing groups and/or electron-withdrawing atomic groups, which polymer has a ratio of the bond energy at 25° C. of electron-withdrawing groups and/or electron-withdrawing atomic groups present in a smallest unit of the polymer to the bond energy at 25° C. of the smallest unit of the polymer of at least 0.13,
 wherein the nanofiber has an average fiber diameter of at least 1 nm but less than 1,000 nm.   
   
   
       2 . The antibacterial nanofiber of  claim 1  wherein, in surface functional group measurement using an acid-base titration method, the ratio of functional groups in a specific weight of the nanofiber to functional groups in a film of the same weight that is formed of the polymer is at least 1.3. 
   
   
       3 . The antibacterial nanofiber of  claim 1  or  2  which is composed solely of the polymer having electron-withdrawing groups and/or electron-withdrawing atomic groups. 
   
   
       4 . The antibacterial nanofiber  claim 1 , wherein the polymer is a polyester resin, a polyamide resin, a polyurethane resin, a polyacrylonitrile resin, a polyamideimide resin, a polyvinyl chloride resin or a polystyrene resin. 
   
   
       5 . The antibacterial nanofiber of  claim 4 , wherein the polymer is a water-insoluble polymer. 
   
   
       6 . The antibacterial nanofiber of  claim 4 , wherein the polyurethane resin is an ester-type polyurethane resin. 
   
   
       7 . The antibacterial nanofiber of  claim 6 , wherein the average fiber diameter is from 1 to 300 nm. 
   
   
       8 . The antibacterial nanofiber of  claim 4  wherein the polyamide resin has, in an infrared absorption spectrum thereof, a ratio A 2 /A 1  between the height A 1  of a peak near 1550 cm −1  and the height A 2  of a peak near 1640 cm −1  of from 1.2 to 1.8. 
   
   
       9 . The antibacterial nanofiber of  claim 8  wherein the ratio A 2 /A 1  is from 1.3 to 1.6. 
   
   
       10 . The antibacterial nanofiber of  claim 1  which is obtained by electrostatic spinning. 
   
   
       11 . The antibacterial nanofiber of  claim 8  which is obtained by electrostatically spinning a solution prepared by dissolving the polyamide resin in formic acid. 
   
   
       12 . The antibacterial nanofiber of  claim 1  for use in antibacterial textile products. 
   
   
       13 . A textile material comprising the antibacterial nanofibers of  claim 1 . 
   
   
       14 . The textile material of  claim 13  which includes no antibacterial agent other than antibacterial nanofibers. 
   
   
       15 . A textile material which consists solely of the antibacterial nanofibers of  claim 1 . 
   
   
       16 . The textile material of  claim 13  which is a nonwoven fabric. 
   
   
       17 . A method of manufacturing antibacterial nanofibers, the method comprising the step of spinning, by an electrostatic spinning process, a solution prepared by dissolving a polymer having electron-withdrawing groups and/or electron-withdrawing atomic groups in an organic solvent. 
   
   
       18 . The method of manufacturing antibacterial nanofibers of  claim 17 , wherein the polymer having electron-withdrawing groups and/or electron-withdrawing atomic groups is a polyamide resin, and the organic solvent is formic acid.