METHOD FOR PRODUCTION OF CELLULOSE ACETATE FIBRE Russian patent published in 1999 - IPC

FIELD: fibre production machinery and technology. SUBSTANCE: according to method, cellulose is activated by swelling and treatment by concentrated acetic acid by spraying acid onto cellulose. Treated cellulose is mixed in mixing silos, discharged, washed, centrifuged, dried. Then following operations are performed: mixing of produced cellulose acetate with titanium dioxide, dissolving in water-acetone mixture, filtration, pressing through die into enclosed shaft machine blown through with hot air, oiling, packing with winding in hard or soft package such as spool, toroid, twisting by rotating package with spreading thread and by means of thread carriers directing to receiving member of twisting machine. Used acetone is recuperated by means of sorption and at least by single absorption by activated carbon and desorption by treating with live steam. Recuperated material is directed to rectification and neutralization with subsequent delivery to storage for repeated use. Activity of carbon is restored by drying and cooling. Dissolving is effected in mixture of acetone and water taken in proportion of 96-96: 4-5 having degree of mineralization as to content of ions of bivalent metals /0.001-0.03/ 10^-2. At presence of hydrochlorides of alkali metals in amount of 1,5 10^-4 to 1,5 10^-2 g/eq/kg of cellulose acetate. Application of aforesaid method improves quality of fibre. EFFECT: higher efficiency. 22 cl, 2 tbl