Method For The Production Of Non-Woven, Non-Woven, And Use Thereof

Abstract

The invention relates to a method for the production of non-woven fabrics, in which a lyotropic solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO) is spun into a plurality of filament yarns by means of extrusion through a nozzle beam containing a plurality of openings via an air gap into a regenerating bath, said filament yarns being intermingled subsequently by being subjected to a flow with gaseous medium and/or fluid. The invention likewise relates to non-woven fabrics of this type and the use thereof.

1 . Method for the production of non-woven fabrics, in which a lyotropic solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO) is spun into a plurality of filament yarns by means of extrusion through a nozzle block containing at least 20 openings via an air gap into a regenerating bath, said filament yarns being intermingled subsequently by being subjected to a flow with gaseous medium and/or fluid.  
     
     
         2 . Method according to  claim 1 , characterised in that a nozzle block with at least 10,000 openings is used.  
     
     
         3 . Method according to  claim 1 , characterised in that the ratio of length to diameter of the nozzles is from 1 to 20.  
     
     
         4 . Method according to  claim 1 , characterised in that the width of the air gap between nozzle and regenerating bath is 5 to 150 mm, in particular 10 to 50 mm.  
     
     
         5 . Method according to  claim 1 , characterised in that the filament yarns are guided downwards after spinning into a slot-shaped funnel, the intermingling with the gaseous medium and/or fluid being effected at the outlet of the funnel.  
     
     
         6 . Method according to  claim 5 , characterised in that a further intermingling of the filament yarns is achieved by a shaking movement of the funnel.  
     
     
         7 . Method according to  claim 1 , characterised in that air and/or water are used as gaseous medium and/or fluid.  
     
     
         8 . Method according to  claim 1 , characterised in that the filament yarns are laid on a conveyor belt after the intermingling.  
     
     
         9 . Method according to  8 , characterised in that a further intermingling of the filament yarns is achieved by a shaking movement of the conveyor belt.  
     
     
         10 . Method according to  claim 1 , characterised in that the cellulose carbamate proportion of the lyotropic solution is at least 20% by weight, in particular 22 to 27% by weight, relative to the solution.  
     
     
         11 . Method according to  claim 1 , characterised in that the lyotropic solution is produced by swelling of the cellulose carbamate in a 40 to 70%, in particular a 50% solution of NMMNO in water and subsequent removal of the water up to a ratio of NMMNO to water between 80:20 and 90:10.  
     
     
         12 . Method according to  claim 1 , characterised in that the regenerating bath comprises a solution of NMMNO in water with an NMMNO proportion of 0.5 to 25% by weight, in particular 5 to 15% by weight, relative to the solution.  
     
     
         13 . Method according to  claim 1 , characterised in that the extrusion is effected at a temperature between 80 to 110° C., in particular 85 to 95° C.  
     
     
         14 . Method according to  claim 1 , characterised in that the non-woven fabric is subsequently washed, pressed and dried.  
     
     
         15 . Method according to  claim 14 , characterised in that the washing is effected by a water jet at high pressure.  
     
     
         16 . Method according to  claim 1 , characterised in that the cellulose carbamate is regenerated into cellulose in a regenerating bath.  
     
     
         17 . Method according to  claim 16 , characterised in that the regenerating bath comprises 0.3 to 1% by weight sodium hydroxide in water and the regeneration is effected at a temperature of 60 to 95° C.  
     
     
         18 . Method according to  claim 16 , characterised in that the regeneration is implemented between extrusion and intermingling.  
     
     
         19 . Method according to  claim 16 , characterised in that the regeneration is implemented after the intermingling.  
     
     
         20 . Non-woven fabric comprising a random orientation of filament yarns made of cellulose carbamate.  
     
     
         21 . Non-woven fabric according to  claim 20 , characterised in that the filament yarns have a strength of at least 60 cN/tex.  
     
     
         22 . Non-woven fabric according to  claim 20 , characterised in that the non-woven fabric can be produced according to the method according to a method for the production of non-woven fabrics, in which a lyotropic solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO) is spun into a plurality of filament yarns by means of extrusion through a nozzle block containing at least 20 openings via an air gap into a regenerating bath, said filament yarns being intermingled subsequently by being subjected to a flow with gaseous medium and/or fluid.  
     
     
         23 . Non-woven fabric comprising a random orientation of filament yarns made of regenerated cellulose.  
     
     
         24 . Non-woven fabric according to  claim 23 , characterised in that the residual N-content is from 0.3 to 0.5%, in particular 0.1 to 0.2%.  
     
     
         25 . Non-woven fabric according to  claim 23 , characterised in that the non-woven fabric has a pore structure with a porosity of 1 to 10%.  
     
     
         26 . Non-woven fabric according to  claim 23 , characterised in that the non-woven fabric has a specific internal surface between 20 and 50 m 2 /cm 3 , measured by means of small angle x-ray scattering (SAXS).  
     
     
         27 . Non-woven fabric according to  claim 23 , characterised in that the non-woven fabric can be produced with a method for the production of non-woven fabrics, in which a lyotropic solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO) is spun into a plurality of filament yarns by means of extrusion through a nozzle block containing at least 20 openings via an air gap into a regenerating bath, said filament yarns being intermingled subsequently by being subjected to a flow with gaseous medium and/or fluid characterised in that the cellulose carbamate is regenerated into cellulose in a regenerating bath.  
     
     
         28 . Use of the non-woven fabrics according to  claim 20  in medicine, in particular as operating sheets, bed sheets, surgical dressings, gauzes or cotton wool pads.  
     
     
         29 . Use of the non-woven fabrics according to  claim 20  as hygiene materials or as household wipes.  
     
     
         30 . Use of the non-woven fabrics according to  claim 20  as decorative non-woven fabrics, in particular tablecloths, serviettes or curtains.  
     
     
         31 . Use of the non-woven fabrics according to  claim 20  as non-woven liners in the clothing industry.  
     
     
         32 . Use of the non-woven fabrics according to  claim 20  as reinforcing mats or isolating jackets in the building industry.  
     
     
         33 . Use of the non-woven fabrics according to  claim 20  as reinforcing material for fibre-reinforced thermoplastic and duroplastic plastic materials.