Nanofiber and nonwoven fabric

Abstract

An object of the invention is to provide a nanofiber having excellent uniformity of the fiber diameter and capable of giving a satisfactory external appearance in a case in which the nanofiber is used to produce a nonwoven fabric, and a nonwoven fabric produced using the nanofiber. The nanofiber of the invention is a nanofiber containing a cellulose acylate having a degree of substitution of from 2.75 to 2.95.

What is claimed is: 
     
         1 . A nanofiber comprising a cellulose acylate having a degree of substitution that satisfies Formula (1):
   2.75≤Degree of substitution≤2.95  (1)
   
     
     
         2 . The nanofiber according to  claim 1 , wherein a proportion of an average fiber length with respect to an average fiber diameter is 1,000 or higher. 
     
     
         3 . The nanofiber according to  claim 1 , wherein an average fiber diameter is 50 to 800 nm. 
     
     
         4 . The nanofiber according to  claim 1 , wherein an average fiber length is 500 μm or more. 
     
     
         5 . The nanofiber according to  claim 1 , wherein an acyl group carried by the cellulose acylate is an acetyl group. 
     
     
         6 . The nanofiber according to  claim 1 , wherein a hemicellulose amount of the cellulose acylate is 0.1% to 3.0% by mass. 
     
     
         7 . The nanofiber according to  claim 2 , wherein a hemicellulose amount of the cellulose acylate is 0.1% to 3.0% by mass. 
     
     
         8 . The nanofiber according to  claim 3 , wherein a hemicellulose amount of the cellulose acylate is 0.1% to 3.0% by mass. 
     
     
         9 . The nanofiber according to  claim 4 , wherein a hemicellulose amount of the cellulose acylate is 0.1% to 3.0% by mass. 
     
     
         10 . The nanofiber according to  claim 5 , wherein a hemicellulose amount of the cellulose acylate is 0.1% to 3.0% by mass. 
     
     
         11 . The nanofiber according to  claim 1 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         12 . The nanofiber according to  claim 2 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         13 . The nanofiber according to  claim 3 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         14 . The nanofiber according to  claim 4 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         15 . The nanofiber according to  claim 5 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         16 . The nanofiber according to  claim 6 , wherein a viscosity of a solution obtained by dissolving the nanofiber in dichloromethane to a concentration of 6% by mass is 300 mPa·s or higher. 
     
     
         17 . A nonwoven fabric comprising the nanofiber according to  claim 1 . 
     
     
         18 . A nonwoven fabric comprising the nanofiber according to  claim 6 . 
     
     
         19 . A nonwoven fabric comprising the nanofiber according to  claim 11 . 
     
     
         20 . The nonwoven fabric according to  claim 17 , wherein the nonwoven fabric is used for a medical filter or a face mask.