Abstract: The process for preparing water-soluble mixed cellulose ethers proceeds in the following steps:(a) alkalization of the cellulose,(b) etherification of the alkali cellulose in the presence of a base, using at least one etherifying agent which requires, for the reaction with cellulose, a catalytic and sub-stoichiometric quantity of a base, and(c) after increasing the quantity of base, further etherification of the cellulose ether so prepared, using at least one etherifying agent which requires, for the reaction with cellulose, an at least stoichiometric quantity of a base or a catalytic and sub-stoichiometric quantity of a base, increased over the quantity used in (a),with at least one inert organic solvent being used as a dispersing auxiliary in at least one of the steps and water being present in all steps. The organic solvent used is dimethyl ether, which either is used alone or in a mixture with dimethoxyethane, an alkanol, an alkanediol and/or an alkoxyalkanol.

Abstract: The process for preparing mixed cellulose ethers proceeds in the following steps:(a) alkalizing of the cellulose,(b) etherifying of the alkali cellulose in the presence of a base by using at least one etherifying agent which requires, for the reaction with cellulose, a catalytic and sub-stoichiometric quantity of a base, and(c) increasing the quantity of base, and(d) etherifying the cellulose ether so prepared by using at least one etherifying agent which requires, for the reaction with cellulose, an at least stoichiometric quantity of a base or a catalytic and substoichiometric quantity of a base, increased over the quantity used in (a),with at least one inert organic solvent being used as a dispersing auxiliary in at least one of the steps and water being present in all steps, wherein mixed etherification leads to a water-soluble product and dimethoxyethane, an alkanol, an alkanediol and/or an alkoxyalkanol are used as the organic solvents.

Abstract: This invention relates to a process for the preparation of acrylic polymers which are at least for the most part insoluble in water and have a high swellability in water, by reacting polyacrylonitrile or copolymers based on acrylonitrile at a temperature exceeding 100.degree. C. with aqueous-alkaline solutions which may contain an organic solvent which is miscible with water.

Abstract: This invention relates to an improvement in the process for the manufacture of modified starch ethers in which, prior to, during, or after etherification, a reaction with a modifying agent is conducted in a wet alkaline medium, the improvement comprising that, if etherification were the only reaction conducted, an at least preponderantly water-soluble starch ether would be formed, and the modification results in an absorbent modified starch ether more than 40 per cent by weight of which is insoluble in water.

Abstract: This invention relates to an improvement in the method for the cold-milling of a cellulose derivative, in which the cellulose derivative is cooled by means of liquid nitrogen until it becomes brittle and the thus cooled cellulose derivative is milled in a mill, the improvement comprising cold-milling a cellulose derivative which is soluble or swellable in water and has a water content of between 40 and 150 percent by weight, based on its dry weight, and which is, at 20.degree. C, able to absorb, during swelling, more than 150 percent by weight of water, based on its dry weight.