To obtain an electrolyte excellent in a property to disperse a slightly water-soluble surfactant by copolymerizing a (meth)acrylamide alkyl sulfonic acid (salt), a specific quaternary ammonium cation monomer and a specific hydrophobic monomer in a specific ratio.
An ampholytic amphipatic polymer electrolyte comprises a copolymer of (A) a (meth)acrylamide alkyl sulfonic acid and/or a salt thereof, (B) a quaternary ammonium cation monomer of formula I and (C) a hydrophobic monomer of formula II and contents of components A and B are each 10-70 mol.% based on the total monomers composing this copolymer. In formula I, R1 is H or 1-2C alkyl; A is an oxygen atom or NH; X is a 1-8C linear or branched alkylene group or alkenylene group; and R2, R3 and R4 are each 1-12C alkyl. In formula II, R and A have each the same meaning as in formula I; and Y is 1-30C linear or branched alkyl or the like.
TOKI IKUKO
NAMITA KENJI
