FOSFONMETYLSUBSTITUENT INNEHAOLLANDE VATTENLOESLIGA CELLULOSABLANDETRAR OCH FOERFARANDE FOER FRAMSTAELLNING AV DEM

Disclosed are water-soluble cellulose mixed ethers which contain (a) at least one substituent from the group comprising alkyl, hydroxyalkyl, carboxyalkyl, sulfoalkyl and dialkylaminoalkyl and (b) a phosphonomethyl substituent and which has a DS of the first substituent(s) other than hydroxyalkyl from about 0.05 to 2.95 and/or an MSHAlk from about 0.5 to 6 and a DSPM from about 0.005 to 0.8. Also disclosed is a process for preparing such cellulose mixed ethers in which, per mole of the cellulose, from about 0.1 to 25 moles of the etherifying agent(s) for producing the substituent(s) under (a), from about 0.05 to 2 moles of halogenomethane phosphonate ions as the etherifying agent for producing the substituent under (b) and from about 0.8 to 12 moles of hydroxide ions are caused to react in a reaction mixture comprising up to about 30 parts by weight, per part by weight of the cellulose, of a mixture which is composed of an inert, preferably water-miscible organic solvent and H2O and in which the proportion of water ranges from about 3 to 40 percent by weight.