Patent ID: 6958393

Claim:
A process for preparing a cellulose derivative having gel-like rheological properties in aqueous solution, comprising: a) alkanizing cellulose with aqueous alkali metal hydroxide in the presence of a suspension medium; b) reacting the alkalized cellulose with one or more alkylene oxides, thereby forming an alkalized cellulose; c) reacting the alkalized cellulose of step (b) with an alkyl halide present in the suspension medium; d) reacting subsequently or simultaneously with step (c) the alkalized cellulose of step (c) with a crosslinklng agent in an amount of 0.0001 to 0.05 eq. where the unit “eq” represents the molar ratio of crosslinking agent relative to the anhydroglucose unit (AGU) of the cellulose used, thereby forming an irreversibly crosslinked cellulose derivative; e) optionally adding a member selected from the group consisting of alkali metal hydroxide, alkylating agent and combinations thereof; f) optionally separating off the irreversibly crosslinked cellulose derivative from the reaction mixture; and g) optionally purifying and drying the isolated irreversibly crosslinked cellulose derivative.