Hoechst Aktiengesellschaft

Gerhard Buchberger

Arno Holst

Michael Kostrzewa

Utz-Hellmuth Felcht

Eberhard Perplies

The process for preparing water-soluble mixed cellulose ethers proceeds in the following steps:

Preparation of water-soluble mixed cellulose ethers

The process for preparing mixed cellulose ethers proceeds in the following steps:

Preparing water-soluble mixed cellulose ethers

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.

Acrylic polymers having a high swellability in water

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.

Process for the manufacture of absorbent, modified starch ethers and

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.

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Wiesbaden-Auringen, Germany

Gerhard Buchberger