Patent ID: 7091221

Claim:
A partial ester of a nitrogenous carboxylic acid with cellulose or its salt, wherein said partial ester contains at least one of glucose unit represented by formula (I) wherein A 1 , A 2 , and A 3 independently represent a hydrogen atom or a nitrogenous acyl group represented by formula (II) provided that all of A 1 , A 2 , and A 3 are not hydrogen atoms wherein R 2 represents a hydrogen atom, an alkyl group having 1˜6 carbon atoms, an amino group or a protonated amino group, R 3 represents a hydrogen atom, an alkyl group having 1˜6 carbon atoms or an aryl group, R 4 represents a hydrogen atom, an alkyl group having 1˜4 carbon atoms, a hydroxyl group, a mercapto group or a nitrogenous substituent represented by formulae (III) or (IV) wherein R 5 , R 6 and R 7 independently represent a hydrogen atom, an alkyl group having 1˜6 carbon atoms, an amino group, an amidino group, a nitroamidino group, a protonated amino group or a protonated amidino group, R 5 may bond with R 2 , R 3 or R 6 to form a ring, and n represents an integer of 0˜20, and wherein R 2 may bond with R 3 to form a ring; with the proviso that when R 2 not an amino group or a protonated amino group, R 4 is any one of the nitrogenous substituents represented by the formulae (III) or (IV); and when R 4 is not any one of the nitrogenous substituents represented by the formulae (III) or (IV), R 2 is an amino group or a protonated amino group; and with a proviso that the nitrogenous carboxylic acid is not glycine, alanine, aminoenanthic acid, aminocaproic acid or p-aminobenzoic acid.