Process for producing a nonwoven material, plant for implementing it and nonwoven thus obtained

Abstract

This invention concerns a method and an installation for producing a spunbonded fabric, characterized in that it consists in: producing a spunbonded lap ( 5 ) against the surface of which is delivered at least a web (V 1 and/or V 2 ) of discontinuous fibers, obtained by carding. The formed complex is compacted by pressing and is continuously transferred onto a line ( 10 ) for water jet binding treatment, driving the fibers in the direction of thickness, the fibers which are bound together like a splice between and around the continuous filaments while remaining visible at the surface. After drying, the final product is obtained.

1 . A process for the production of a nonwoven of “spunbond” type having mechanical properties equivalent to spunbond webs consolidated by hot calendering and having the appearance, the handle and the pliancy of a conventional textile, which consists in continuously: 
 producing a web (S) of “spunbond” type, the bundle of continuous filaments, which is extruded and drawn, being collected in the form of a nonbonded web on a moving conveyor belt;  
 delivering, against at least one face of the “spunbond” web thus formed, a sheet (V 1  and/or V 2 ) consisting of natural and/or artificial and/or synthetic, discontinuous fibers, obtained by carding and having a grammage of between 10 g/m 2  and 50 g/m 2 ;  
 compacting the complex thus formed by cold pressing it;  
 transferring, still continuously, said complex onto a treatment line ( 10 ) for bonding it by means of water jets which act against the surface or surfaces of the complex consisting of discontinuous fibers and entrain said fibers in the thickness direction, which fibers bond together in the manner of a splice between and around the continuous filaments, while still remaining visible on the surface;  
 carrying out a drying treatment;  
 and then collecting the finished product.  
 
     
     
         2 . The process as claimed in  claim 1 , characterized in that the web ( 5 ) of “spunbond” type is covered on both its faces with a sheet (V 1 /V 2 ) of discontinuous fibers, one lap (V 1 ) being produced directly upstream of the zone in which the “spunbond” web is formed and being taken onto the conveyor belt ( 11 ) on which the filaments coming from the “spunbond” plant are deposited, said filaments therefore being distributed over the surface of this sheet (V 1 ), the second lap (V 2 ) being delivered downstream of the zone in which the web of continuous filaments is formed, which web is thus sandwiched between the two fibrous layers (V 1 , V 2 ).  
     
     
         3 . The process as claimed in either of claims  1  and  2 , characterized in that, after the water-jet bonding operation and before drying, a complementary “textiling” treatment is carried out which consists in transferring the bonded complex onto a coarse fabric ( 22 ) and in subjecting the web to the action of water jets which are obtained by means of a unit essentially comprising a perforated rotary drum ( 24 ) inside which an injector ( 23 ) fed with pressurized water is placed, this unit producing jets which reorient the fibers, a suction unit ( 25 ) for removing the water being provided beneath the conveyor.  
     
     
         4 . A plant for producing a nonwoven of “spunbond” type, comprising, arranged in line: 
 a unit ( 1 ) for forming, on a conveyor belt ( 5 ), a web (S) of continuous filaments of “spunbond”type;  
 at least one carding machine ( 6  and/or  9 ) for delivering, against at least one face of the “spunbond” web produced, a sheet (V 1  and/or V 2 ) of discontinuous fibers and having a grammage of between 10 g/m 2  and 50 g/m 2 ;  
 means for cold pressing the complex formed, followed by a zone ( 10 ) for treatment by means of fluid jets, which act at least against the surface covered with discontinuous fibers and entrain said fibers in the thickness direction, which fibers bond together in the manner of a splice between and around the continuous fibers, while still being visible on the surface;  
 means for drying and collecting the bonded web, characterized in that it includes, between the water-jet bonding means ( 10 ) and the drying means, a textiling unit delivering a coarse fabric ( 22 ) which is intended to support the bonded complex and is associated with a perforated rotary drum inside which an injector ( 23 ) fed with pressurized water is placed, this unit producing jets which reorient the fibers, a suction unit ( 25 ) for removing the water being placed beneath the conveyor.  
 
     
     
         5 . The plant as claimed in  claim 4 , characterized in that it includes, upstream and downstream of the zone in which the “spunbond” web is formed, means ( 6 ,  9 ) for producing a sheet of fibers, the sheet (V 1 ) produced upstream being delivered onto the conveyor belt ( 5 ) of the “spunbond” line, the bundle of filaments, which is extruded and drawn, being collected directly on said sheet, the second sheet (V 2 ) being placed downstream of the zone in which the “spunbond” web is formed and being delivered onto the surface of the latter.  
     
     
         6 . A nonwoven obtained by implementing the process as claimed in one of  claims 1  to  3 , characterized in that it is composed of a web produced from continuous filaments combined with discontinuous fibers, which fibers cover at least one face of the continuous-filament-based web and penetrate the interior of the latter, by becoming bonded around said filaments.