High strength cellulosic filament its use, and method for the production thereof

Abstract

The present invention relates to high-strength, possibly pigment-containing—for example flame-retardant—regenerated cellulosic filaments having improved textile properties, in particular as regards strength and uniformity, to their use for the production of fabrics, and to a method for the production of these filaments.

1 . A regenerated cellulose filament, wherein the filament has a pigment content of more than 20 wt % and a strength in the conditioned state of more than 22 cN/tex. 
     
     
         2 . The regenerated cellulose filament according to  claim 1 , wherein the pigment is selected from the group consisting of flame-retardant, colored, fluorescent and radiographically detectable pigments. 
     
     
         3 . The regenerated cellulose filament according to  claim 2 , wherein the pigment has a particle size distribution with x 50  at less than 1.0 μm and x 99  at less than 5.0 μm. 
     
     
         4 . The regenerated cellulose filament according to  claim 2 , wherein the filament has a single-fiber titer of between 0.4 and 4.0 dtex. 
     
     
         5 . The regenerated cellulose filament according to  claim 2 , which comprises at least 2.8%, phosphorus related to cellulose. 
     
     
         6 . The regenerated cellulose filament according to  claim 2 , wherein the phosphorus is 2,2′-oxybis[5,5-dimethyl-1,3,2-dioxaphosphorinane]2,2′disulfide (I). 
     
     
         7 . The regenerated cellulose filament according to  claim 2 , wherein the filament comprises a dispersing agent selected from the group consisting of modified polycarboxylates, water-soluble polyesters, alkyl ether phosphates, end-group-capped nonyl phenol ethoxylates, castor oil alkoxyl esters, and carboxymethylated alcohol polyglycol ethers. 
     
     
         8 . A regenerated cellulose filament having a strength in the conditioned state of greater than 36 cN/tex. 
     
     
         9 . A textile fabric comprising the regenerated cellulose filament according to  claims 1  or  2 . 
     
     
         10 . A continuous method for the production of a high-strength regenerated cellulose filament comprising:
 1) spinning a viscose containing 4 to 8% cellulose, 5 to 10% NaOH, 36 to 42% (related to cellulose) carbon disulfide and 1 to 5% (related to cellulose) of a modifier into a precipitation bath to form coagulated filaments,   2) withdrawing and reeling up the coagulated filaments, wherein:
 a viscose is used whose spinning gamma value is 50 to 68 and whose spinning viscosity is 50 to 150 falling ball seconds; 
 the temperature of the precipitation bath is 34 to 65° C.; 
 the alkali ratio (=cellulose concentration/alkali content) of the ready-to-spin viscose is 0.7 to 1.5; 
 the bath concentrations are:
 H 2 SO 4  68-95 g/1 
 Na 2 SO 4  90-160 g/1 
 ZnSO 4  30-65 g/1; and 
 
 the withdrawing and reeling up take place at a velocity between 15 and 180 m/min; and 
   3) passing the coagulated filaments in the precipitation bath through a second bath, wherein the second bath comprises aqueous sulfuric acid, 3-7 wt %, at a temperature of 80-98° C. to form the regenerated cellulosic filaments.   
     
     
         11 . The method according to  claim 10 , wherein pulp having an α-content of 93-99% is used as cellulosic raw material. 
     
     
         12 . The method as according to  claim 10 , wherein the coagulated filaments are stretched by 70% to 105% in the second bath. 
     
     
         13 . The method according to  claim 10 , wherein a pigment-type substance in the form of a pigment dispersion is spun into the filaments. 
     
     
         14 . The method according to  claim 13 , wherein the pigment dosing ratio is controlled and/or adapted automatically based on the spinning solution flow rate and adjusted by means of a controlled dosing pump. 
     
     
         15 . The method according to  claim 14 , wherein the controlled dosing pump is an eccentric screw pump. 
     
     
         16 . The method according to  claim 13 , wherein the pigment-type substance is selected from the group consisting of flame-retardant, colored, fluorescent, and radiographically detectable pigments. 
     
     
         17 . The method according to  claim 16 , wherein the pigment-type substance is at least partly a flame-retardant substance. 
     
     
         18 . The method according to  claim 17 , wherein the high-strength regenerated cellulose filament comprises at least 2.8% phosphorus related to cellulose. 
     
     
         19 . The method according to  claim 18 , wherein the phosphorus is 2,2′-oxybis[5,5-dimethyl-1,3,2-dioxaphosphorinane]2,2′disulfide (I). 
     
     
         20 . The method according to  claim 17 , wherein the pigment dispersion contains between 10 and 50% of the flame-retardant substance with an average particle size (x 50 ) of less than 1.0 μm and a maximum particle size (x 99 ) of less than 5.0 μm and between 1.5 and 20% of a dispersing agent. 
     
     
         21 . The method according to  claim 17 , wherein a dispersing agent is used to disperse the flame retardant substance, wherein the dispersing agent is selected from the group consisting of modified polycarboxylates, water-soluble polyesters, alkyl ether phosphates, end-group-capped nonyl phenol ethoxylates, castor oil alkoxyl esters, and carboxymethylated alcohol polyglycol ethers. 
     
     
         22 . The method according to  claim 10 , wherein the spinning of the viscose into the precipitation path takes place in the form of a tube spinning method. 
     
     
         23 . The flame-retardant regenerated cellulose filament according to  claim 5 , which comprises between 3.2% and 6.0% phosphorus related to cellulose. 
     
     
         24 . The flame-retardant regenerated cellulose filament according to  claim 5 , which comprises between 3.5% and 6.0% phosphorus related to cellulose. 
     
     
         25 . The method according to  claim 17 , wherein the high-strength regenerated cellulose filament comprises between 3.2% and 6.0% phosphorus related to cellulose. 
     
     
         26 . The method according to  claim 17 , wherein the high-strength regenerated cellulose filament comprises between 3.5% and 6.0% phosphorus related to cellulose.