Fine-fibers-dispersed nonwoven fabric, process and apparatus for manufacturing same, and sheet material containing same

Abstract

Disclosed is a fine-fibers-dispersed nonwoven fabric comprising dispersed fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, wherein an adhesion rate of substances adhered to the nonwoven fabric is 0.5 mass % or less. Further, a process and an apparatus for manufacturing the fine-fibers-dispersed nonwoven fabric, as well as a sheet material comprising the fine-fibers-dispersed nonwoven fabric are also disclosed.

1 . A fine-fibers-dispersed nonwoven fabric comprising fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less in a dispersed state, wherein an adhesion rate of substances adhered to said nonwoven fabric is 0.5 mass % or less.  
     
     
         2 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the adhesion rate of substances adhered is 0.08 mass % or less.  
     
     
         3 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the fine fibers contained in the nonwoven fabric are not substantially entangled.  
     
     
         4 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the fiber diameter of the fine fiber is 2 μm or less.  
     
     
         5 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the fine fibers are formed from island components remaining after removing a sea component from islands-in-sea type fibers.  
     
     
         6 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the fine fibers are formed from one or more organic components.  
     
     
         7 . The fine-fibers-dispersed nonwoven fabric according to  claim 1 , wherein the fine fibers are fused.  
     
     
         8 . A process for manufacturing a fine-fibers-dispersed nonwoven fabric comprising the steps of: 
 ejecting aggregates of fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or a group of the aggregates, and/or mechanically dividable fibers capable of generating fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or aggregates of the mechanically dividable fibers, from a nozzle into a gas by an action of a compressed gas, to thereby divide the aggregates or the group thereof into the fine fibers, and/or divide the mechanically dividable fibers or the aggregates thereof into the fine fibers, and disperse the resulting fine fibers;    collecting the dispersed fine fibers to form a fiber web; and    bonding the fiber web to obtain the fine-fibers-dispersed nonwoven fabric.    
     
     
         9 . The process according to  claim 8 , wherein, in addition to the fine-fibers aggregates or the group thereof, and/or the mechanically dividable fibers or the aggregates thereof, other fibers or the aggregates thereof are ejected from the nozzle.  
     
     
         10 . The process according to  claim 8 , wherein bundled aggregates of fine fibers are ejected from the nozzle.  
     
     
         11 . The process according to  claim 8 , wherein before supplying the fine-fibers aggregates or the group thereof, and/or the mechanically dividable fibers or the aggregates thereof to the nozzle, adhered substances are removed from the fine-fibers aggregates or the group thereof, and/or the mechanically dividable fibers or the aggregates thereof.  
     
     
         12 . The process according to  claim 8 , wherein a gas stream passing through the nozzle is substantially a laminar flow.  
     
     
         13 . The process according to  claim 8 , wherein the fine-fibers aggregates or the group thereof, and/or the mechanically dividable fibers or the aggregates thereof are ejected from the nozzle and brought into collision with a colliding means placed in front of the nozzle.  
     
     
         14 . An apparatus for manufacturing a fine-fibers-dispersed nonwoven fabric comprising 
 (1) a nozzle capable of ejecting aggregates of fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or a group of the aggregates, and/or mechanically dividable fibers capable of generating fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or aggregates of the mechanically dividable fibers, into a gas by an action of a compressed gas;    (2) a means for supplying the compressed gas to the nozzle;    (3) a dispersing chamber for dividing the fine-fibers aggregates or the group thereof, and/or the mechanically dividable fibers or the aggregates thereof ejected from the nozzle into a gas by an action of the compressed gas into the fine fibers, and dispersing the fine fibers;    (4) a support on which the fine fibers dispersed in the gas in the dispersing chamber are collected to form a fiber web; and    (5) a thermal fusing means for heating the fiber web on the support.    
     
     
         15 . A sheet material comprising at least one layer of a fine-fibers-dispersed nonwoven fabric layer containing dispersed fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, wherein an adhesion rate of substances adhered to said nonwoven fabric layer is 0.5 mass % or less.  
     
     
         16 . The sheet material according to  claim 15 , further comprising one or more reinforcing layers.  
     
     
         17 . A process for manufacturing a sheet material comprising the steps of: 
 ejecting aggregates of fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or a group of the aggregates, and/or mechanically dividable fibers capable of generating fine fibers having a fiber diameter of 4 μm or less and a fiber length of 3 mm or less, or aggregates of the mechanically dividable fibers, from a nozzle into a gas by an action of a compressed gas, to thereby divide the aggregates or the group thereof into the fine fibers, and/or divide the mechanically dividable fibers or the aggregates thereof into the fine fibers, and disperse the resulting fine fibers;    collecting the dispersed fine fibers on a reinforcing substrate to form a fiber web on the reinforcing substrate; and    bonding the fiber web, and the fiber web and the reinforcing substrate to obtain the sheet material comprising the fine-fibers-dispersed nonwoven fabric layer and the reinforcing layer.