Cellulosic solutions containing fire retardant and method of extruding

Claim 1

A PROCESS OF PRODUCING REGENERATED CELLULOSE MATERIALS WHICH HAVE AFTERGLOW-RESISTANT AND FIRE-RETARDANT PROPERTIES WHICH COMPRISES EXTRUDING AN AQUEOUS ALKALINE CELLULOSE SOLUTION WHICH FORMS REGENERATED CELLULOSE ON ACIDFICATION CONTAINING AN AMOUNT OF A NEUTRAL TO ALKALINE WATER-SOLUBLE REACTION PRODUCT OF PHOSPHORLY CHLORIDE AND AMMONIA SUFFICEINT TO IMPART AFTERGLOW-RESISTANT AND FIRE RETARDANT PROPERTIES TO A DRY, REGENERATED CELLLULOSE MATERIAL PREPARED BY ACIDIFCATION OF SAID SOLUTION, THROUGH A SHAPING ORIFICE INTO AN ACIDIC AQUEOUS COAGULATING SOLUTION SUBJECTING THE THUS EXTRUDED SOLUTION TO THE ACTION OF AN AQUEOUS ACID SOLUTION UNTIL THE SOLUTION IS COAGULATED AND SAID REACTION PRODUCT IS PRECIPITATED IN SITU THEREIN AS A WATER-INSOLUBLE PRODUCT CONVERTING THE COAGULATED SOLUTION TO REGENERATED CELLULOSE WITH AN AQUEOUS ACID SOLUTION AND SUBSEQUENTLY DRYING SAID REGENERATED CELLULOSE SAID WATER-SOLUBLE REACTION PRODUCTHAVING BEEN PREPARED IN AN INERT, ANHYDROUS LIQUID AND HAVING A NITROGEN TO PHOSPHORUS RATIO BETWEEN ABOUT 2.1:1 AND 2.3:1.