Verfahren zur Herstellung von Cellulosecarbamat

Die Erfindung betrifft ein Verfahren zur Herstellung homogener Mischungen von Cellulose und Harnstoff und deren Umsetzung zu Cellulosecarbamat. Die erfindungsgemaess hergestellten Cellulosecarbamate sind in waessriger Alkalilauge loeslich und koennen zur Herstellung von Fasern, Folien, Perlen, Schwaemmen und anderen Formkoerpern auf Cellulosebasis verarbeitet werden.

WO2003099873 A UPAB: 20040115 NOVELTY - Production of cellulose carbamate (I) comprises (a) producing a mixture of activated cellulose or pulp, urea and a high-boiling organic solvent for urea in a mixing aggregate, using mechanical shear; (b) drying the mixture; and (c) conversion to (I) by reaction at 120-220 deg. C. USE - The process is used for producing fibers, films, beads, sponge and sponge cloths (all claimed) and other moldings based on cellulose. ADVANTAGE - Cellulose carbamates provide an alternative to the viscose process for producing regenerated cellulose fibers. However, activation with excess concentrated aqueous sodium hydroxide solution necessitates washing, whilst mixing with solid urea does not give uniform distribution and mixing with aqueous urea solution increases the energy consumption for drying. The present process avoids these drawbacks. It improves activation and homogeneous mixing of activated cellulose with urea before and during reaction and gives a product of more uniform quality.