Flame retardant aid, flame retarding agent composition, and method for producing flame-retardant fiber fabric

A flame retardant aid comprising an amphoteric polymer compound having at least one of cationic unit selected from the group consisting of allylamine-based units expressed by formulas (I), (II) and (III):

• wherein R1 and R2 are each independently a hydrogen atom, a methyl group, an ethyl group, or a cyclohexyl group, R3 is a hydrogen atom, a methyl group, an ethyl group, or a benzyl group, R4 and R5 are each independently a hydrogen atom, a methyl group, an ethyl group, or a benzyl group, A and B can be direct bonds or CH2 provided that when A is a direct bond, B is CH2, and when A is CH2, B is a direct bond, and X− is an anion, and inorganic acid salts and organic acid salts thereof;
• and
• an anionic unit expressed by formula (IV):
• wherein D is H or COOY, E is R6 or COOY, and F is H, COOY, or CH2COOY provided that when D is H, E is COOY and F is COOY or CH2COOY and when D is COOY, E is R6 and F is COOY or E is COOY and F is H, R6 is a hydrogen atom or a methyl group, and Y is each independently selected from the group consisting of a hydrogen atom, Na, K, NH4, ½Ca, ½Mg, ½Fe, ⅓Al, and ⅓Fe.