Low-density nonwoven fabric and production method and installation therefor and uses

Abstract

The invention concerns an installation for nonwoven production, characterized in that it comprises a spunbonded web plant whereof the die is inclined at an angle of 10 to 60° and preferably of 20 to 50° relative to the displacement direction of a conveyor and preferably two spunbonded web plants whereof the dies have opposite inclinations, said conveyor whereon filaments are deposited from the die(s) in the form of a web, a station for compressing the thus formed web into a web compressed perpendicular to its plane, optionally a station for calendering the compressed web, followed by a station for consolidating by pressurized water jet spray the compressed and optionally calendered web with a jet spraying machine comprising a metal fabric whereof the wires have a diameter between 0.10 and 0.35 mm and which has more than 40 wires per cm and preferably 10 to 30 wires per cm both in warp direction and in weft direction or with a water jet spraying machine including a sleeve with perforations of 50 to 600 microns and having 20 to 200 perforations per cm 2 .

1 - 9 . (canceled)  
     
     
         10 . A method of producing a nonwoven, in which filaments are deposited as a web in a plane on a conveyor having a longitudinal direction, the web is compressed, perpendicular to the plane of the web, into a compressed web and then the compressed web is subjected to a consolidation operation by blasting it with water jets having a diameter of 50 to 250 microns at a pressure of 50 to 500 bar to form the nonwoven, including the steps of: 
 depositing the filaments onto the conveyor using at least one spunbond unit including a die which is inclined relative to the longitudinal direction at an angle of 10 to 60°;    and blasting the web with the water jets with either: 
 a) interposition of the web, onto a metal fabric, having warp and weft threads of a diameter between 0.10 mm and 0.35 mm, the warp and weft threads each numbering up to 40 threads per cm, or  
 b) interposition of the web, onto a microperforated sleeve, the dimensions of the perforations being between 50 and 600 microns and the number of perforations being between 50 and 200 per cm 2 .  
   
     
     
         11 . The method of  claim 10 , wherein said die is inclined at an angle of from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         12 . The method as claim in  claim 10 , wherein the metal fabric has a plain, twill or satin weave and a thickness of between 0.40 mm and 0.75 mm.  
     
     
         13 . The method of  claim 10 , further including a second spunbond unit having a second die depositing filaments onto the conveyor, and the second die is inclined relative to the longitudinal direction at an angle of from about 10° to about 60°.  
     
     
         14 . The method of  claim 13 , wherein said dies are inclined in opposite directions.  
     
     
         15 . The method of  claim 13 , wherein each of said dies is inclined at an angle of from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         16 . A method producing a nonwoven having an indefinite length and a width comprising the steps of extruding filaments from a die, depositing the extruded filaments onto a conveyor to form the nonwoven in a plane extending along said conveyor, said nonwoven length extending along the conveyor length and said nonwoven width extending across the conveyor width, disposing the die at an inclined angle relative to the plane of the nonwoven to thereby increase the number of die deposited filaments across the width of the nonwoven as compared with an identically formed nonwoven except that the die is not disposed at said inclined angle relative to the plane of the nonwoven.  
     
     
         17 . The method of  claim 16 , wherein said inclined angle is from about 10° to about 60°.  
     
     
         18 . The method of  claim 16 , further including a second die, extruding filaments from said second die and depositing the extruded filaments onto the conveyor to form the nonwoven, said second die also being inclined relative to the plane of the nonwoven at an angle of from about 10° to about 60°.  
     
     
         19 . The method of  claim 18 , wherein said first mentioned die and said second die are inclined in opposite directions.  
     
     
         20 . The method of  claim 16 , further including the steps of compressing the nonwoven, and consolidating the compressed nonwoven by impinging water jets onto the compressed web.  
     
     
         21 . The method of  claim 20 , wherein the step of impinging water jets onto the compressed nonwoven includes either: 
 a) positioning the compressed nonwoven, onto a metal fabric, having warp and weft threads of a diameter between 0.10 mm and 0.35 mm, the warp and weft threads each numbering up to 40 threads per cm, or    b) positioning the compressed nonwoven, onto a microperforated sleeve, the dimensions of the perforations being between 50 and 600 microns and the number of perforations being between 50 and 200 per cm 2 .    
     
     
         22 . The method of  claim 21 , wherein said inclined angle is from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         23 . The method of  claim 21 , further including a second die, extruding filaments from said second die and depositing the extruded filaments onto the conveyor to form the nonwoven, said second die also being inclined relative to the plane of the nonwoven at an angle of from about 10° to about 60°.  
     
     
         24 . The method of  claim 23 , wherein each of said inclined angles is from about 20° to about 50°  
     
     
         25 . The method of  claim 24 , wherein said first mentioned die and said second die are inclined in opposite directions.  
     
     
         26 . A nonwoven production installation comprising a spunbond unit having a die inclined at an angle of from about 10° to about 60° relative to the direction of movement of a conveyor and arranged to deposit filaments across the width of the conveyor to form a web, a compression station for compressing the web thus formed perpendicular to its plane into a compressed web, and a consolidation station for blasting pressurized water jets onto the compressed web using a water-jet blasting machine to form the nonwoven, the water-jet blasting machine including either (a) a metal fabric, the threads of which have a diameter of between 0.10 mm and 0.35 mm, there being at most 40 threads per cm in each of the warp direction and the weft direction, or (b) a sleeve having 50 to 600 micron perforations, there being 20 to 200 perforations per cm 2 .  
     
     
         27 . The installation of  claim 26 , wherein said angle is from about 20° to about 50° and there are 15 to 30 threads per cm in each of the warp direction and the weft direction.  
     
     
         28 . The installation of  claim 26 , wherein said inclined angle is from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         29 . The installation of  claim 26 , further including a second spunbond unit having a second die inclined at an angle of from about 10° to about 60° relative to the direction of movement of a conveyor.  
     
     
         30 . The method of  claim 29 , wherein each of said dies is inclined at an angle of from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         31 . The installation of  claim 26 , wherein said compression station comprises a calendar for compressing the nonwoven.  
     
     
         32 . The installation of  claim 26 , whereby inclination of the die increases the number of die deposited filaments across the width of the nonwoven as compared with an identically formed nonwoven except that the die is not inclined relative to the direction of movement of the conveyor.  
     
     
         33 . A nonwoven production installation for producing a nonwoven having an indefinite length and a width comprising a die for extruding filaments onto a conveyor to form the nonwoven in a plane extending along said conveyor, said nonwoven length extending along the conveyor length and said nonwoven width extending across the conveyor width, said die being disposed at an inclined angle relative to the plane of the nonwoven to increase the number of die deposited filaments across the width of the nonwoven as compared with an identically formed nonwoven except that the die is not disposed at said inclined angle relative to the plane of the nonwoven.  
     
     
         34 . The installation of  claim 33 , wherein said inclined angle is from about 10° to about 60°.  
     
     
         35 . The installation of  claim 33 , further including a second die for extruding filaments onto the conveyor to form the nonwoven, said second die also being disposed at an inclined angle of from about 10° to about 60° relative to the plane of the nonwoven.  
     
     
         36 . The installation of  claim 35 , wherein said first mentioned die and said second die are inclined in opposite directions.  
     
     
         37 . The installation of  claim 33 , further including a compressing station for compressing the nonwoven in a direction perpendicular to the plane of the nonwoven, and a consolidation station for consolidating the compressed nonwoven including means for impinging water-jets jets onto the compressed nonwoven.  
     
     
         38 . The installation of  claim 37 , wherein the means for impinging water-jets onto the compressed nonwoven include either: 
 a) a metal fabric onto which the compressed web is positioned, the metal fabric having warp and weft threads of a diameter between 0.10 mm and 0.35 mm, the warp and weft threads each numbering up to 40 threads per cm, or    b) a microperforated sleeve onto which the compressed web is positioned, the dimensions of the perforations being between 50 and 600 microns and the number of perforations being between 50 and 200 per cm 2 .    
     
     
         39 . The installation of  claim 38 , wherein said inclined angle is from about 20° to about 50°, said threads have a diameter of diameter between 0.18 mm and 0.30 mm, the warp and weft threads each number between 15 to 30 threads per cm, the dimensions of the perforations are between 150 and 500 microns, and the number of perforations is between 50 and 200 per cm 2 .  
     
     
         40 . The installation of  claim 38 , further including a second die for extruding filaments onto the conveyor to form the nonwoven, said second die also being disposed at an inclined angle of from about 10° to about 60° relative to the plane of the nonwoven.  
     
     
         41 . The installation of  claim 40 , wherein each of said inclined angles is from about 20° to about 50° 
     
     
         42 . The installation of  claim 41 , wherein said first mentioned die and said second die are inclined in opposite directions.