Hoechst Aktiengesellschaft

Acordis Kelheim Gmbh

Tatjana Poggi

Ernst Schubert

Tibor Krakkay

Klaus Fischer

Heinzhorst M&ouml;bius

Geza Hidasi

In the manufacture of viscose, and an elongate cellulose member such as standard viscose rayon fibre, with reduced alkali ratio from dissolving-grade cellulose such as wood pulp by irradiation with a high energy beam at a dose of 1-30 kGy, steeping in aqueous sodium hydroxide, pressing to form alkali cellulose, xanthating to form cellulose xanthate, dissolving in aqueous liquor to form viscose and (when elongate cellulose members are required) extruding through a die into an acid bath for coagulation and regeneration to form an elongate cellulose member which is then washed and dried, viscose filtration can be improved by including in the dissolving liquor for the cellulose xanthate an amount of from 200 to 10000 ppm by weight of a salt which consists of alkali metal or ammonium cations and anions of a strong acid.

Manufacture of viscose and of articles therefrom

A process for producing viscose wherein the caustic soda used previously in the alkalization of electron-untreated cellulose can be used in the alkalization of electron-treated cellulosic material, provided the level of dispersed solids in the caustic soda does not exceed 0.16 g/l.

Method for viscose production

The invention relates to homopolymers and copolymers of acrylonitrile with very low Fikentscher K values of 34-15 and a total content of sulfonate and sulfate end groups, which do not originate from correspondingly substituted comonomers, of 250 to 1,000 milliequivalents per kilogram of polymer, 180 to 900 milliequivalents per kilogram being in the form of sulfonate end groups, and to suitable semi-continuous or continuous precipitation polymerization processes for their preparation by means of a redox system in an aqueous medium. The resulting polymers can be extruded to shaped articles. In particular, after hydrolysis, they can be used as emulsifiers and deep bore auxiliaries.

Process for preparation of acrylonitrile polymers with low K value

A method of inhibiting scale formation or precipitation in an aqueous alkaline-earth salt solution with an aqueous solution of a hydrolyzed polyacrylonitrile salt made by heating homopolymers and copolymers of acrylonitrile with very low Fikentscher K values of 34-15 and a total content of sulfonate and sulfate end groups, which do not originate from correspondingly substituted comonomers, of 250 to 1,000 milliequivalents per kilogram of polymer, 180 to 900 milliequivalents per kilogram being in the form of sulfonate end groups, and to suitable semi-continuous or continuous precipitation polymerization process for their preparation by means of a redox system in an aqueous medium.

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Saal, Germany

Tatjana Poggi