Cation-modified acrylamide or methacrylamide copolymer as well as antistatic agent, thermoplastic resin composition, aqueous composition and thermoplastic resin laminate comprising same

The present invention provides a cation-modified linear copolymer which comprises, within the molecule thereof, 95 to 85 mole % of an ethylene structural unit, 0.1 to 10 mole % of an ester structural unit represented by general formula (II), 0.1 to 6 mole % of an acrylic or methacrylic acid structural unit and 1 to 12 mole % of an amide structural unit represented by general formula (IV) and has a weight-average molecular weight of 1,000 to 100,000. When incorporated in thermoplastic resins, it shows good compatibility and brings about good mechanical properties.