Flame retardant cellulosic man-made fibers

Abstract

The invention relates to flame-retardant cellulosic man-made fibers containing a flame-retardant substance in the form of an oxidized condensate of a tetrakis hydroxyalkyl phosphonium salt with ammonia and/or a nitrogenous compound which contains one or several amine groups whereby the fiber has a tenacity of more than 18 cN/tex in a conditioned state. Production process and the use of the fibers according to the invention are further objects of the invention.

1 . A flame-retardant cellulosic man-made fiber comprising a flame-retardant substance in the form of an oxidized condensate of a tetrakis hydroxyalkyl phosphonium salt with ammonia and/or a nitrogenous compound which contains one or several groups of amine groups, wherein the fiber has a strength of more than 18 cN/tex in a conditioned state. 
     
     
         2 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the nitrogenous compound is selected from the group consisting of urea, ammonia, thiourea, biuret, melamine, ethylene urea, guanidine and 2-cyanoguanidine. 
     
     
         3 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the tetrakis hydroxyalkyl phosphonium salt is a tetrakis hydroxymethyl phosphonium salt. 
     
     
         4 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the fiber is a viscose or modal fiber. 
     
     
         5 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the cellulosic man-made fiber is a cupro or carbamate fiber. 
     
     
         6 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the fiber is a lyocell fiber. 
     
     
         7 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the share of flame-retardant substance in the cellulose fiber is between 5-50 weight percent. 
     
     
         8 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the fiber strength is from 18 cN/tex to 50 cN/tex. 
     
     
         9 . The flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the fiber comprises additives. 
     
     
         10 . A process for the production of flame-retardant cellulosic man-made fibers according to of  claim 1  from a spinning mass comprising the steps
 producing of a viscose of cellulose xanthogenate 
 adding a modification agent 
 adding of 5 weight percent to 50 weight percent of a flame-retardant agent in relation to the cellulose in the form of a aqueous dispersion of the pigment 
 spinning of spinning mass through a spinneret into a spinning bath 
 stretching of precipitated filaments 
 after-treating via washing, bleaching, finishing 
 cutting to staple fibers, 
 and wherein for the production of the fiber 
 the pulp used has a R-18 content of 93-98% 
 the cellulose content of the viscose is between 4 and 7% 
 the alkali ratio is between 0.7 and 1.5 
 the carbon disulphide used equals 36 weight percent to 42 weight percent in relation to the cellulose 
 between 1 weight percent and 5 weight percent of a modifying agent, in relation to the cellulose, is added to the viscose 
 the spinning gamma value of the viscose lies between 50 und 68, preferably between 55 and 58 
 die spinning viscosity equals 50 to 120 falling ball seconds 
 the temperature of the spin bath is between 34 to 48° C. 
 the following spin bath concentrations are used
 H 2 SO 4  68-90 g/l 
 Na 2 SO 4  90-160 g/l 
 ZnSO 4  30-65 g/1 
 
 the final drawing-off from the spinning bath is performed at a speed of between 15 und 60 m/min. 
 
     
     
         11 . A process for the production of flame-retardant cellulosic man-made fibers according to  claim 1  according to the lyocell process, wherein a flame-retardant substance is added prior to the extrusion of the spinning mass and the share of flame-retardant substance in the cellulose fiber is 5 weight percent to 50 weight percent. 
     
     
         12 . A process for the production of flame-retardant cellulosic man-made fibers according to  claim 1 , wherein the flame-retardant substance is washed with acid and finally with water before adding to the spinning mass as such, respectively before producing a dispersion thereof. 
     
     
         13 . A yarn comprising a flame-retardant cellulosic man-made fiber according to  claim 1 . 
     
     
         14 . A textile material comprising a flame-retardant cellulosic man-made fiber according to  claim 1 . 
     
     
         15 . A textile material comprising a flame-retardant cellulosic man-made fiber according to one of  claim 1 , wherein the textile fabric respectively the non-woven fulfils the demands in accordance with EN ISO 14 116 classification “limited flame spread index 3”, when testing according to EN ISO 15025:2002 Process B—edge flaming. 
     
     
         16 . A yarn or textile fabric comprising a flame-retardant cellulosic man-made fiber according to one of  claim 1 , wherein the flame-retardant cellulosic fiber is blended with fibers of a natural or synthetic origin. 
     
     
         17 . The yarn or textile fabric  claim 16 , wherein the blend comprises fibers, which themselves are inherently flame-retardant or treated with a flame-retardant agent. 
     
     
         18 . The yarn or textile fabric according to  claim 16 , wherein the flame-retardant cellulosic man-made fiber is present in a blend with polyester, modacryl, para- and meta-Aramide, polyamidimide, flame-retardant wool, polybenzimidazol, polyimide, polyamide, polyamide, flame-retardant acrylic fibers, melamine fibers, polyphenylene sulphide, polytetrafluorethylene, glass fibers, cotton, silk, carbon fibers, oxidized thermally stabilized polyacrylonitrile fibers and electrically conductive fibers and blends of these fibers. 
     
     
         19 . A yarn or textile fabric comprising a flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the flame-retardant cellulosic man-made fiber is present in a blend with meta- or para-polyaramide—respectively polyimide fibers. 
     
     
         20 . A flame-retardant cellulosic man-made fiber according to  claim 1 , wherein the fiber comprises an oxidized condensate from a tetrakis hydroxyalkyl phosphonium compound and a nitrogenous compound, and wherein a molar ratio of tetrakis hydroxyalkyl phosphonium compound to the nitrogen compound is in the range of 1: (0.05 to 2.0). 
     
     
         21 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the nitrogenous compound is selected from the group consisting of urea, ammonia, thiourea, biuret, melamine, ethylene urea, guanidine and dicyandiamide. 
     
     
         22 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the nitrogenous compound is urea or ammonia. 
     
     
         23 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the hydroxyalkyl group of the tetrakis hydroxyalkyl phosphonium compound is selected from the group consisting of hydroxymethyl, hydroxyethyl, hydroxypropyl or hydroxybutyl groups. 
     
     
         24 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the tetrakis hydroxyalkyl phosphonium compound is a tetrakis hydroxymethyl phosphonium salt. 
     
     
         25 . The flame-retardant cellulosic man-made fiber according to  claim 7 , wherein the share of flame-retardant substance in the cellulose fiber is between 10-30 weight percent. 
     
     
         26 . The flame-retardant cellulosic man-made fiber according to  claim 7 , wherein the share of flame-retardant substance in the cellulose fiber is between 15-25 weight percent. 
     
     
         27 . The flame-retardant cellulosic man-made fiber according to  claim 9 , wherein the additives are selected from the group consisting of color pigments or bactericides. 
     
     
         28 . The process according to  claim 11 , wherein the share of flame-retardant substance in the cellulose fiber is 10 weight percent to 30 weight percent. 
     
     
         29 . The process according to  claim 11 , wherein the share of flame-retardant substance in the cellulose fiber is 15 weight percent to 25 weight percent. 
     
     
         30 . The textile material according to  claim 15 ,  16 ,  17 ,  18  or  19  wherein the textile material is a non-woven material. 
     
     
         31 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the molar ratio of tetrakis hydroxyalkyl phosphonium compound to the nitrogen compound is in the range of 1: (0.5 to 1.5). 
     
     
         32 . The flame-retardant cellulosic man-made fiber according to  claim 20 , wherein the molar ratio of tetrakis hydroxyalkyl phosphonium compound to the nitrogen compound is in the range of 1: (0.65 to 1.2).