High-shrinkage acrylic fiber, spun yarn containing the same, and step pile fabric using the spun yarn

Abstract

Provided are an acrylic fiber suitable for a step pile fabric such as a high-pile textile, a spun yarn containing said fiber, and a pile fabric in which said spun yarn is used. In the present invention, the acrylic fiber is a high-shrinkage acrylic fiber having a single-filament fineness of 1-7 dtex, a shrinkage of 20-40%, and post-shrinking bulkiness of 0.19×10 1 -0.30×10 1 mm 3 /g; or an acrylic fiber having a single-filament fineness of 2-7 dtex, elongation of 50-70%, and bulkiness of 0.19×10 1 -0.30×10 1 mm 3 /g.

1 . A high-shrinkage acrylic fiber, wherein
 a single-filament fineness is set at 1˜7 dtex,   a shrinkage rate is set at 20˜40%, and   a post-shrink bulkiness is set at 0.19×10 1 ˜0.30×10 1  mm 3 /g.   
     
     
         2 . An acrylic fiber, wherein
 a single-filament fineness is set at 2˜7 dtex,   an elongation rate is set at 50˜70%, and   a bulkiness is set at 0.19×10 1 ˜0.30×10 1  mm 3 /g.   
     
     
         3 . The acrylic fiber according to  claim 2 , wherein a minimum value of the second moment of area per unit fineness is at least 600 μm 4  in a direction where the second moment of area is smallest, and a maximum value of the second moment of area per unit fineness is at least 2200 μm 4  in a direction where the second moment of area is greatest. 
     
     
         4 . The acrylic fiber according to  claim 2 , wherein the minimum value of the second moment of area per unit fineness is at least 4000 μm 4  in a direction where the second moment of area is smallest. 
     
     
         5 . The acrylic fiber according to  claim 2 , wherein any of requirements (I), (II) and (Ill) described below is satisfied:
 (I) The cross section of a fiber is formed with a circle and rectangle, where the rectangle having a short side shorter than the diameter of the circle penetrates through the circle in such a way that both ends of the rectangle are positioned outside the circle: when the length of the long side of the rectangle is set as “a” and the length of the short side as “b,” “a/b” is 3˜25; and when the diameter of the circle is set as “W” and the shorter height of the maximum heights measured respectively from each of both long sides of the rectangle inside the circle is set as “H,” “W” is a/10˜4a/5, and “H” is 2/b˜2b.   (II) The cross section of a fiber has a triangular shape: when the length of the longest side of the triangle is set as “C” and the height from the longest side of the triangle positioned at the base is set as “B,” B/C is 0.5 or greater.   (Ill) The cross section of a fiber has a dumbbell shape and the degree of narrowing (X/Y) is 1.1˜2.5.   “X” is the maximum length of major diameter between narrowed ends.   “Y” is the length at the narrowest portion.   
     
     
         6 . The acrylic fiber according to  claim 2 , comprising an acrylonitrile-based polymer containing an acrylonitrile unit at 50 mass % or greater. 
     
     
         7 . A spun yarn, comprising the acrylic fiber according to  claim 1  at 20˜50 mass %. 
     
     
         8 . A step pile fabric, comprising:
 a long-pile portion; and   a short-pile portion,   wherein the short-pile portion contains the acrylic fiber according to  claim 2 , and its rate of recovery from compression is set at 35˜90.   
     
     
         9 . The step pile fabric according to  claim 8 , wherein the amount of acrylic fiber contained in the short-pile portion is set at 20˜50 mass % of the entire pile portion. 
     
     
         10 . The step pile fabric according to  claim 8 , wherein the base of pile is in the initial state of spun yarn. 
     
     
         11 . The step pile fabric according to  claim 8 , wherein the length of the short-pile portion is set at 5˜20 mm. 
     
     
         12 . The step pile fabric according to  claim 8 , wherein the length of the long-pile portion is set at 6˜40 mm. 
     
     
         13 . The step pile fabric according to  claim 8 , wherein the long-pile portion comprises at least one of acrylic fiber, polyester fiber and animal fiber at 50˜100 mass % of the entire long-pile portion. 
     
     
         14 . The step pile fabric according to claim  8 , wherein the long-pile portion is set to have a single-filament fineness of 1˜50 dtex. 
     
     
         15 . The step pile fabric according to  claim 8 , wherein the cross-section of acrylic fiber or polyester fiber in a fiber axial direction has a flat shape, Y-shape, UFO-shape, or dumbbell shape. 
     
     
         16 . The step pile fabric according to  claim 8 , wherein the difference in length between the long-pile portion and short-pile portion is set to be 1˜20 mm.