| abstract |
FIELD: chemistry. n SUBSTANCE: invention relates to the method for the producing a polysaccharide derivative that comprises: (a) converting, at least, one polysaccharide having a crystallinity (CI) of, at least, 20% measured by the XRD method to contact with, at least, one compound at the temperature of not more than 70°C; and (b) subsequently bringing the product produced in step (a) into contact with, at least, one aromatic isocyanate. The aromatic isocyanate is a polyisocyanate selected from the group consisting of: methylenediphenyl diisocyanate represented by its 2,4'-, 2,2'- and 4,4'-isomers, as well as mixtures thereof, mixtures of methylenediphenyl diisocyanates and their oligomers, or their derivatives having urethane, isocyanurate, allophonate, biuret, uretonimine, uretdione and/or iminooxadiazinedione groups, as well as mixtures thereof, to produce a polysaccharide derivative having a crystallinity index of, at least, 50% of the relevant value of, at least, one polysaccharide. n EFFECT: increasing the yield. n 15 cl, 2 dwg, 2 tbl |