Fabrication of natural cellulose fiber with flame-retarding capability

A fabrication process for producing natural cellulose fibers with flame-retarding properties which comprises the following steps:

• (a) blending a raw material of wood pulp with a solvent of N-methylmorpholine N-oxide (NMMO) to form a slurry;
• next additionally adding a mix stabilizer comprising 1,3-phenylene-bis 2-oxazoline into the slurry;
• then agitate and crush the slurry of wood pulp, N-methylmorpholine N-oxide (NMMO) and 1,3-phenylene-bis 2-oxazoline (BOX) in a horizontal slurry blending machine under low temperature between 60 and 80 degrees Celsius;
• wherein, said wood pulp is a hard wood or soft wood cellulose pulp with an α-cellulose content being over 65% and a degree of polymerization (DP) being between 500-1200;
• (b) evaporate extra water content from the slurry by a Thin Film Evaporator (TFE) under a temperature between 80 and 120 degrees Celsius and heating for 5 minutes to remove extra water content so that a spinning dope is formed with a water content of 5%-13%;
• (c) by means of Dry-Jet Wet Spinning method, spin the prepared spinning dope and extrude said spinning dope out of a plurality of spinnerets and into a coagulation bath, then coagulate said spinning dope in the coagulation bath and regenerate it into spinning filaments;
• (d) water-rinse and dry the spinning filaments under a temperature between 100 and 130 degree Celsius heating for 3-5 minutes to form a natural cellulose fiber;
• (e) rolling soak the natural cellulose fiber with a flame retardant composition of of N-(hydroxymethyl)-3-(methoxy phosphorus acyl) such that the proportion of rolling liquid is 65%-70% and the concentration of N-(hydroxymethyl)-3-(methoxy phosphorus acyl) is 250 g/L-500 g/L;
• (f) orderly heating dry, twice baking, neutralizing, soaping clean, water rinse and baking dry the soaking rolled natural cellulose fiber, wherein the heating dry is performed under temperature at 105 degrees Celsius heating for 10 seconds,
• wherein the first bake is performed under temperature between 130 and 155 degrees Celsius, heating for 60-120 seconds;
• the neutralizing is performed in an alkaline solution with concentration of 50 g/L under temperature between 20 and 30 degrees Celsius,
• and the soaping clean is performed in an alkaline solution with concentration of 2 g/L having soaping powder concentration of 3 g/L under a temperature between 20-30 degrees for 10 seconds;
• and
• (g) successively alkaline clean, water rinse, dry and oil the natural cellulose fiber to produce natural cellulose fiber with long-acting flame retarding capacity, then either obtain long filament via coiling means or short staple via cutting means.