Flame-resistant cellulosic fiber, its use and production process

Abstract

The present invention relates to a flame-retardant cellulosic regenerated fiber for textile applications which for example also satisfies the demands of industrial dry cleaning, its use for the production of yarns and fabrics and a process for the production of these fibers.

1 . A flame-resistant regenerated cellulose fiber for textile applications, wherein said fiber comprises an incorporated flame resistant substance comprised of a particle-shaped phosphorous compound wherein said fiber has a usability value of between 6 and 35. 
     
     
         2 . The flame-resistant fiber according to  claim 1 , wherein said fiber comprises at least 2.8% of phosphorous in relation to cellulose. 
     
     
         3 . The flame-resistant fiber according to  claim 1  or  2 , wherein the phosphorous compound is 2,2′-oxybis[5,5-dimethyl-1,3,2-dioxaphosphorinane]2,2′ disulfid(I). 
     
     
         4 . The flame-resistant fiber according to  claim 1  or  2 , having a BISFA wet modulus (B m )≧0.5·(√T)·10/T and an elongation of 5% in the wet condition. 
     
     
         5 . The flame-resistant fiber according to  claim 1  or  2 , wherein the flame-resistant substance has a particle size distribution at X 50  less than 1.0 μm and x 99  less than 5.0 μm. 
     
     
         6 . The flame-resistant fiber according to  claim 1  or  2 , wherein the flame-resistant substance originates from a dispersion and wherein said dispersion comprises a dispersing agent selected from the group consisting of modified polycarboxylates, water-soluble polyester, alkyletherphosphates, end-capped nonoxynols, recinus oil alkoxylester and carboxymethylated alcoholpolyglcolether. 
     
     
         7 . A yarn comprising the fiber according to  claim 1  or  2 . 
     
     
         8 . A fabric comprising the fiber according to  claim 1  or  2 . 
     
     
         9 . A process for the production of a flame-resistant regenerated cellulose fiber for textile applications which comprises
 (a) spinning viscose with a content of 4 to 7% cellulose, 5 to 10% NaOH, 36 to 42% (in relation to cellulose) carbon disulphide and 1 to 5% (in relation to cellulose) of a modification agent into a spinning bath; and   (b) drawing off of coagulated threads, wherein the viscose has a spinning gamma value of 50 to 68 and a spinning viscosity of 50 to 120 ballfall seconds; and that the temperature of the spinning bath equals 34 to 48° C., characterized in that
 1) an alkali ratio (=cellulose concentration/alkali content) of the viscose ready for spinning equals 0.7 to 1.5; 
 2) the following spinning bath concentrations are used:
 i) H 2 S0 4 =68-90 g/l 
 ii) Na 2 S0 4 =90-160 g/l 
 iii) ZnS0 4 =30-65 g/L; 
 
 3) the drawing off from the spinning bath takes place at a speed between 15 and 60 m/min and 
 4) a particle shaped phosphorous compound in the form of a pigment dispersion is incorporated during spinning as a flame-resistant substance. 
   
     
     
         10 . The process according to  claim 9 , wherein an amount of the flame-resistant substance is incorporated to result in a finished fiber comprising at least 2.8% of phosphorous, in relation to cellulose. 
     
     
         11 . The process according to  claim 9 , wherein the phosphorus compound is 2,2′-oxybis[5,5-dimethyl-1,3,2-dioxaphosphorinane]2,2′ disulphide (I). 
     
     
         12 . The process according to  claim 9 , wherein the pigment dispersion comprises between 10 and 50% of the flame-resistant substance with an average particle size (x 90 ) less than 1.0 μm and a maximum particle size (X 99 ) less than 5.0 μm, and between 1.5 and 20% of a dispersing agent. 
     
     
         13 . The process according to  claim 12 , wherein the dispersing agent to disperse the flame-resistant substance in the pigment dispersion, and wherein the dispersing agent is selected from the group consisting of modified polycarboxylates, water-soluble polyester, alklyetherphosphates, end-capped nonoxynols, recinus oil alkoxylester and carboxmethylated alcoholpolyglycolether. 
     
     
         14 . The flame-resistant regenerated cellulose fiber according to  claim 1 , wherein said fiber has a usability value of between 8 and 35. 
     
     
         15 . The flame-resistant regenerated cellulose fiber according to  claim 14 , wherein said fiber has a usability value of between 10 and 35. 
     
     
         16 . The flame-resistant fiber according to  claim 2 , wherein said fiber comprises between 3.2% and 6.0% of phosphorous in relation to cellulose. 
     
     
         17 . The flame-resistant fiber according to  claim 2 , wherein said fiber comprises between 3.5% and 6.0% of phosphorous in relation to cellulose. 
     
     
         18 . The process according to  claim 10 , wherein the amount of the flame-resistant substance incorporated results in a finished fiber comprising between 3.2% and 6.0% of phosphorous in relation to cellulose. 
     
     
         19 . The process according to  claim 18 , wherein the amount of the flame-resistant substance incorporated results in a finished fiber comprising between 3.5% and 6.0% of phosphorous in relation to cellulose.