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 . Flame-retardant cellulosic man-made fiber 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 groups of amine groups, characterized in that the fiber has a strength of more than 18 cN/tex in a conditioned state. 
     
     
         2 . Flame-retardant cellulosic man-made fiber according to  claim 1 , characterized in that the nitrogenous compound is selected from the group of urea, ammonia, thiourea, biuret, melamine, ethylene urea, guanidine and 2-cyanoguanidine. 
     
     
         3 . Flame-retardant cellulosic man-made fiber according to  claim 1  or  2 , characterized in that the tetrakis hydroxyalkyl phosphonium salt is preferably a tetrakis hydroxymethyl phosphonium salt. 
     
     
         4 . Flame-retardant cellulosic man-made fiber according to  claims 1  to  3 , characterized in that the fiber is a viscose or modal fiber. 
     
     
         5 . Flame-retardant cellulosic man-made fiber according to one of  claims 1  to  3 , characterized in that the cellulosic man-made fiber is a cupro or carbamate fiber. 
     
     
         6 . Flame-retardant cellulosic man-made fiber according to one of  claims 1  to  3 , characterized in that the fiber is a lyocell fiber. 
     
     
         7 . Flame-retardant cellulosic man-made fiber according to one of the previous claims, characterized in that the share of flame-retardant substance in the cellulose fiber is between 5%-50 weight percent, preferably between 10-30 weight percent and most preferably between 15-25 weight percent. 
     
     
         8 . Flame-retardant cellulosic man-made fiber according to one of the previous claims, characterized in that the tenacity is from 18 cN/tex to 50 cN/tex. 
     
     
         9 . Flame-retardant cellulosic man-made fiber according to one of the previous claims, characterized in that the fiber contains additional additives, such as colour pigments or bactericides. 
     
     
         10 . Process for the production of flame-retardant cellulosic man-made fibers according to one of  claims 1 ,  2 ,  3 ,  4 ,  7 ,  8  and  9  from a spinning mass comprising the steps
 production of a viscose of cellulose xanthogenate 
 adding a modification agent 
 addition 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-treatment via washing, bleaching, finishing 
 cutting to staple fibers, 
 and is characterized in that 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 and 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/l 
 
 
 the final drawing-off from the spinning bath is performed at a speed of between 15 und 60 m/min. 
 
     
     
         11 . Process for the production of flame-retardant cellulosic man-made fibers according to one of  claims 1 ,  2 ,  3 ,  6 ,  7 ,  8  und 9 according to the lyocell process, characterized in that 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 equals 5 weight percent to 50 weight percent, preferably 10 weight percent to 30 weight percent and most preferably 15 weight percent to 25%. 
     
     
         12 . Process for the production of flame-retardant cellulosic man-made fibers according to one of  claims 1  to  11 , characterized in that 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 . Yarn containing a flame-retardant cellulosic man-made fiber according to one of  claims 1  to  12 . 
     
     
         14 . Use of a flame-retardant cellulosic man-made fiber according to one of  claims 1  to  13  for the production of a textile material respectively a non-woven. 
     
     
         15 . Textile materials respectively non-wovens containing a flame-retardant cellulosic man-made fiber according to one of  claims 1  to  14 , characterized in that 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 . Yarn, textile fabric respectively non-woven containing a flame-retardant cellulosic man-made fiber according to one of  claims 1  to  15 , characterized in that the flame-retardant cellulosic fiber is blended with fibers of a natural or synthetic origin. 
     
     
         17 . Yarn, textile fabric respectively non-woven according to  claim 16 , characterized in that the blend comprises fibers, which themselves are inherently flame-retardant or treated with a flame-retardant agent. 
     
     
         18 . Yarn, textile fabric respectively non-woven according to  claim 16  or  17 , characterized in that 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 . Yarn, textile fabric respectively non-woven containing a flame-retardant cellulosic man-made fiber according to one of  claims 1  to  18 , characterized in that the flame-retardant cellulosic man-made fiber is present in a blend with meta- or para-polyaramide—respectively polyimide fibers. 
     
     
         20 . Use of an oxidized condensate from a tetrakis hydroxyalkyl phosphonium compound with a nitrogenous compound as a flame-retardant agent in a cellulosic man-made fiber according to one of the previous claims, characterized in that the molar ratio of tetrakis hydroxyalkyl phosphonium compound to the nitrogen compound is in the range of 1: (0,05 to 2,0), preferably 1: (0.5 to 1.5), most preferably 1: (0.65 to 1.2). 
     
     
         21 . Use according to  claim 20 , characterized in that the nitrogenous compound is selected from the group of urea, ammonia, thiourea, biuret, melamine, ethylene urea, guanidine and dicyandiamide. 
     
     
         22 . Use according to  claims 20  and  21 , characterized in that the nitrogenous compound is urea or ammonia. 
     
     
         23 . Use according to  claims 20  to  22 , characterized in that the hydroxyalkyl group of the tetrakis hydroxyalkyl phosphonium salt is selected from hydroxymethyl, hydroxyethyl, hydroxypropyl or hydroxybutyl groups. 
     
     
         24 . Use according to  claims 20  to  23 , characterized in that the tetrakis hydroxyalkyl phosphonium compound is a tetrakis hydroxymethyl phosphonium salt.