Patent ID: 8455001

Claim:
A cellulose derivative having a repeating unit of the formula where R 1 , R 2 , and R 3 are independently selected from the group consisting of (a), (b), (c), and (d) below, —H (a) —CH 2 —COOH (b) —CH 2 —COOX (c) X in (c) being an alkali metal or an alkali earth metal, R 4 and R 5 in (d) being independently an alkenyl group having 9 to 19 carbon atoms, a degree of substitution of (b) and (c) being 0.3 to 2.0 in total, and a degree of substitution of (d) being 0.001 to 0.05, wherein the repeating unit can vary depending on its substituents, wherein R 1 , R 2 , and R 3 are not all hydrogen atoms in at least some repeating units.