Multi-layered non-woven fabric and process and apparatus for producing the same

Abstract

A process for producing a multi-layered non-woven fabric includes: (a) forming a plurality of non-woven fabric layers from a plurality of filament materials which are produced respectively from a plurality of spinning devices disposed along an advancing forming screen; (b) forming at least one of the filament materials as a composite filament material which includes at least two filament components having high and low melting points by means of one of the spinning devices; and (c) depositing the filament materials on the advancing forming screen one over the other to form a plurality of non-woven fabric layers. An apparatus to carry out the process, and a multi-layered non-woven fabric produced thereby are also disclosed.

I claim:  
     
         1 . A process for producing a multi-layered non-woven fabric, comprising: 
 (a) forming a plurality of non-woven fabric layers from a plurality of filament materials which are produced respectively from a plurality of spinning devices disposed along an advancing forming screen;    (b) forming at least one of said filament materials as a composite filament material which includes at least two filament components having high and low melting points by means of one of said spinning devices; and    (c) depositing said filament materials on said advancing forming screen one over the other to form a plurality of non-woven fabric layers.    
     
     
         2 . The process as claimed in    claim 1   , wherein said composite filament material includes a bicomponent filament which is formed by extruding two polymeric compositions having high and low melting points.  
     
     
         3 . The process as claimed in    claim 2   , wherein each of said filament materials is formed as said composite filament material.  
     
     
         4 . The process as claimed in    claim 3   , wherein said composite filament material is formed by a melt-blowing process.  
     
     
         5 . The process as claimed in    claim 3   , wherein said composite filament material is formed by a spun-bonding process.  
     
     
         6 . The process as claimed in    claim 3   , wherein said non-woven fabric layers comprise a first spun-bonded composite fabric layer, a first melt-blown composite fabric layer formed on said first spun-bonded composite fabric layer, a second melt-blown composite fabric layer formed on said first melt-blown composite fabric layer, and a second spun-bonded composite fabric layer formed on said second melt-blown composite fabric layer.  
     
     
         7 . The process as claimed in    claim 6   , wherein, after step (c), said non-woven fabric layers are heat-treated at a temperature lower than said high melting point so as to heat-bond only one of said filament components having said low melting point.  
     
     
         8 . The process as claimed in    claim 7   , wherein said non-woven fabric layers are heat-treated by passing between a pair of heat-embossing rollers.  
     
     
         9 . The process as claimed in    claim 7   , wherein said non-woven fabric layers are heat-treated by passing through a hot air box.  
     
     
         10 . The process as claimed in    claim 5   , wherein, after step (c), said non-woven fabric layers are subjected to a water jet so as to split said composite filament materials into fine filaments.  
     
     
         11 . A multi-layered non-woven fabric, comprising: 
 a plurality of non-woven fabric layers bonded together to form a laminate, said non-woven fabric layers being obtained from a plurality of filament materials which are produced respectively by a plurality of spinning devices disposed along an advancing forming screen, at least one of said non-woven fabric layers containing a composite filament material which includes at least two filament components having high and low melting points.    
     
     
         12 . The multi-layered non-woven fabric as claimed in    claim 11   , wherein said composite filament material includes a bicomponent filament.  
     
     
         13 . The multi-layered non-woven fabric as claimed in    claim 12   , wherein said non-woven fabric layers include at least one melt-blown composite fabric layer and at least one spun-bonded composite fabric layer.  
     
     
         14 . The multi-layered non-woven fabric as claimed in    claim 13   , wherein said melt-blown composite fabric layer has a melt-blown composite filament with a diameter of less than 5 μm.  
     
     
         15 . The multi-layered non-woven fabric as claimed in    claim 13   , wherein said non-woven fabric layers comprise a first spun-bonded composite fabric layer, a first melt-blown composite fabric layer formed on said first spun-bonded composite fabric layer, a second melt-blown composite fabric layer formed on said first melt-blown composite fabric layer, and a second spun-bonded composite fabric layer formed on said second melt-blown composite fabric layer.  
     
     
         16 . The multi-layered non-woven fabric as claimed in    claim 13   , wherein each of said composite filament materials of said spun-bonded composite fabric layer and said melt-blown composite fabric layer is prepared from a bicomponent combination selected from the group consisting of a combination of polypropylene and polyethylene, a combination of polyethylene terephthalate and polyethylene, a combination of polyethylene terephthalate and polypropylene, a combination of polypropylene and compound polypropylene (COPP), a combination of polyethylene terephthalate and compound polyethylene terephthalate, and a combination of nylon with a high melting point and nylon with a low melting point.  
     
     
         17 . An apparatus for producing a multi-layered non-woven fabric, comprising: 
 an advancing forming screen;    a plurality of spinning devices disposed successively adjacent to and along the direction of said forming screen so as to extrude a plurality of filament materials, respectively, at least one of said spinning devices producing a composite filament material from at least two polymeric compositions; and    depositing means for depositing said filament materials one over the other on said forming screen to form a plurality of non-woven fabric layers.    
     
     
         18 . The apparatus as claimed in    claim 17   , wherein said spinning devices include at least one spun-bonding spinning device, and at least one melt-blowing spinning device disposed downstream of said spun-bonding spinning device, each of said spinning devices comprising two extruders.