Cationic group-containing cellulose ether

A cationic group-containing cellulose ether, which has a main chain derived from an anhydroglucose represented by the following general formula (1), and in which the degree of substitution with a cationized oxyalkylene group per the anhydroglucose unit is from 0.01 to 1.0, the degree of substitution with a glycerol group is from 0.5 to 5.0, and the degree of substitution with a group that contains a branched hydrocarbon group having from 8 to 18 carbon atoms and is represented by any of the following general formulae (6) to (8) is from 0.001 to 0.2:

• wherein R1, R2 and R3 each independently represent a substituent comprising at least one structural unit selected from the following formulae (2) to (8), or a hydrogen atom;
• n indicates a mean degree of polymerization of the anhydroglucose-derived main chain, and is a number of from 100 to 12000,
• wherein the structural unit represented by the formula (2) or (3) is a cationized oxyalkylene group;
• the structural unit represented by the formula (4) or (5) is a glycerol group;
• and the structural unit represented by any of the formulae (6) to (8) is a group that contains a branched hydrocarbon group having from 8 to 18 carbon atoms;
• R4 to R9 each independently represent a linear or branched alkyl group having from 1 to 3 carbon atoms;
• X− and Y− each represent an anion;
• and r and s each indicate an integer of from 0 to 3;
• R10 and R11 each independently represent a branched hydrocarbon group having from 6 to 16 carbon atoms;
• R12 represents a branched hydrocarbon group having from 8 to 18 carbon atoms;
• and p indicates an integer of 0 or 1;
• and, in the structural unit represented by any of the formulae (2) to (7), the oxygen atom bonds to a hydrogen atom or to the carbon atom of the above-mentioned structural unit.