Acrylic composite fiber and method for production thereof, and fiber composite using the same

Abstract

An object of this invention is to provide an acrylonitrile based composite fiber having a new feeling different from that of an ordinary cellulose acetate fiber, cellulose fiber and acrylic fiber, excellent spinability, fiber properties and process ability of yarn spinning, and excellent functions, in particular, a deodorizing function and a moisture absorbing and retaining property. The composite fiber is comprised of 10 to 40% by weight of cellulose acetate and/or cellulose and 60 to 90% by weight of an acrylonitrile based polymer, and has a structure with the cellulose acetate and/or cellulose forming an island component in a cross section perpendicular to a fiber axis and the acrylonitrile based polymer forming a sea component. Preferably, the cellulose acetate and/or cellulose as the island component communicate with another island component in the fiber axis direction, a vacant hole is provided inside the fiber, or a ratio of the longest diameter and the shortest diameter of the fiber cross section is 2 or less, and 5 or more recess parts of 0.3 μm or more and 3 μm or less width and 0.3 μm or more and 3 μm or less depth are provided in a fiber cross section outer circumferential part. Further preferably, by applying a heat treatment under alkali in a production stage, the moisture absorbing and retaining property can be improved.

1 . An acrylic based composite fiber characterized by being composed of 10 to 40% by weight of cellulose acetate and/or cellulose and 60 to 90% by weight of an acrylonitrile based polymer, comprising a structure with the cellulose acetate and/or cellulose forming an island component in a cross section perpendicular to a fiber axis, and the acrylonitrile based polymer forming a sea component.  
     
     
         2 . The acrylic based composite fiber according to  claim 1 , characterized by comprising a structure with the cellulose acetate and/or cellulose as the island component communicating with another island component in a cross section along the fiber axis direction.  
     
     
         3 . The acrylic based composite fiber according to  claim 1  or  2 , characterized by comprising a vacant hole inside the fiber.  
     
     
         4 . The acrylic based composite fiber according to any of  claims 1  to  3 , characterized in that a ratio of the longest diameter and the shortest diameter of a fiber cross section is 2 or less, and 5 or more recess parts of 0.3 un or more and 3 μm or less width and 0.3 μm or more and 3 μm or less depth are provided in a fiber cross section outer circumferential part.  
     
     
         5 . The acrylic based composite fiber according to any of  claims 1  to  4 , characterized in that single fiber strength is 1.8 CN/dTex or more, dry elongation is 30% or more, knot strength is 1.8 CN/dTex or more, and knot elongation is 30% or more.  
     
     
         6 . The acrylic based composite fiber according to any of  claims 1  to  5 , characterized in that a deodorizing ratio with respect to a carboxylic acid is 90% or more.  
     
     
         7 . The acrylic based composite fiber according to any of  claims 1  to  6 , characterized in that the deodorizing ratio with respect to an acetic acid is 95% or more.  
     
     
         8 . The acrylic based composite fiber according to any of  claims 1  to  7 , characterized in that the deodorizing ratio with respect to a nonanal is 90% or more.  
     
     
         9 . The acrylic based composite fiber according to any of  claims 1  to  8 , characterized in that a moisture absorbing ratio Aa under a 40° C. temperature and 90% RH humidity environment is 15.0% or less, a moisture absorbing ratio Ab under a 20° C. temperature and 65% RH humidity environment is more than 2%, and a moisture absorbing ratio difference ΔA (=Aa−Ab) at the time of transfer from the 40° C. temperature and 90% RH humidity environment to the 20° C. temperature and 65% RH humidity environment is less than 1.5.  
     
     
         10 . The acrylic based composite fiber according to  claim 9 , characterized in that the moisture absorbing ratio Aa under the 40° C. temperature and 90% RH humidity environment is 3.0% or more and 8.0% or less, and the moisture absorbing ratio Ab under the 20° C. temperature and 65% RH humidity environment is more than 2% and less than 6.5%.  
     
     
         11 . A method for producing an acrylic based composite fiber, characterized by executing a wet spinning process using a spinning solution obtained by mixing the below-mentioned components (A), (B) and (C): 
 (A) cellulose acetate,    (B) an acrylonitrile based polymer, and    (C) a solvent capable of dissolving both the cellulose acetate and the acrylonitrile based polymer.    
     
     
         12 . A method for producing an acrylic based composite fiber, characterized by spinning by using a spinning solution obtained by mixing a solution with the component (A) dissolved in the component (C) and a solution with the component (B) dissolved in the component (C), each component (A), (B) and (C) being recited in  claim 11 .  
     
     
         13 . A method for producing an acrylic based synthetic fiber, characterized by comprising a step of applying a heat treatment under alkali to an acrylic based synthetic fiber composed of 10 to 40% by weight of cellulose acetate and 60 to 90% by weight of an acrylonitrile based polymer, the acrylic based synthetic fiber having a structure with the cellulose acetate forming an island component in a cross section perpendicular to a fiber axis and the acrylonitrile based polymer forming a sea component.  
     
     
         14 . The method for producing an acrylic based composite fiber according to  claim 13 , characterized in that a weight reduction ratio of the cellulose acetate is 5 to 40%.  
     
     
         15 . A fiber composite characterized by using the acrylic based composite fiber according to any of  claims 1  to  10 .