Process for preparing swellable cross-linked carboxyalkylcelluloses, in the form of fibers, from cellulose hydrate and use thereof

A process for preparing swellable cross-linked carboxyalkylcelluloses in the form of fibers, by reacting cellulose, a carboxyalkylating etherifying agent, and a cross-linking agent in an aqueous alkaline medium, comprising effecting alkalizing, etherifying, and cross-linking simultaneously in one reaction step using fibers of cellulose hydrate or fiber-based textile sheet materials which contain these fibers, by contacting (a) said fibers or textile sheet materials which contain these fibers with an ample quantity of an aqueous alkaline reaction mixture, (b) removing part of the reaction mixture from the fibers or the textile sheet materials contacted therewith, so that at least the quantity required for reaction is still present, wherein the molar relationships of the components of said quantity of the reaction mixture range, relative to 1 mole of cellulose, from about 0.7 to 2.1 moles of alkali hydroxide, about 10 to 30 moles of H.sub.2 O, about 0.7 to 2 moles of the etherifying agent, and about 0.005 to 0.1 mole of the cross-linking agent, and (c) treating the fibers or the textile sheet materials containing said remainder of the aqueous alkaline reaction mixture with heat energy for the purpose of the actual chemical reaction.