FIELD: chemistry.
SUBSTANCE: invention relates to water-soluble cellulose ether, which contains: (i) one or several substituents, selected from the group, which consists of methyl, hydroxyethyl and hydroxypropyl, (ii) one or several non-ionic hydrophobic substituents with acyclic or cyclic, saturated or unsaturated, branched or linear hydrocarbon groups, containing at least 8 carbon atoms, and (iii) one or several cation, tertiary amine or anion substituents, and the average number of moles of one or several hydrophobic substituents per 1 mole of anhydrideglucose units constitutes from 0.007 to 0.025, and weight average molecular weight of cellulose ether constitutes at least 750000, and cellulose ether has residual dynamic viscosity %η80/25, which constitutes at least 30%, where %η80/25 = [dynamic viscosity of solution at 80°C/dynamic viscosity of solution at 25°C]×100, and, dynamic viscosity of solution at 25°C and 80°C is measured in 1% water solution. Water-soluble cellulose ether is useful for modification of composition viscosity, selected from the group, which consists of fluid media for servicing boreholes, cementing compositions, ceramic materials, fluid media for processing metals and lubricant-cooling fluid media.
EFFECT: cellulose ethers demonstrate increased stability to thermal liquefaction.
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