An aqueous polymer dispersion for composite film lamination, comprising at least one dispersed polymer A prepared by radical emulsion polymerization, - where initially in a first stage in aqueous medium a first polymer dispersed in water is prepared by radical emulsion polymerization, the first polymer being prepared from a first composition comprising ethylenically unsaturated radically polymerizable monomers, where the monomers of the first stage comprise at least one monomer having at least one acid group in an amount of at least 0.1 part by weight, based on 100 parts by weight of the total amount of monomers of the first and second stages, and - subsequently in a second stage a polymer dispersion is prepared in aqueous medium and in the presence of the first polymer by radical emulsion polymerization of a second composition comprising ethylenically unsaturated, radically polymerizable monomers, different from the first composition, - where in total less than 0.5 part by weight of emulsifier, based on 100 parts by weight of monomers of the polymer A, or no emulsifier is used, and - where the glass transition temperature of the polymer A prepared is less than 0°C; and at least one polymer B, in solution in the aqueous polymer dispersion and prepared by radical polymerization of at least one ethylenically unsaturated, radically polymerizable monomer having at least one oxazoline group, and at least 5% by weight, based on the total monomer amount of the polymer B, of at least one hydrophilic, ethylenically unsaturated, radically polymerizable monomer without oxazoline group and with a water solubility of at least 100 g/l at 25°C, and optionally further monomers. at least one dispersed polymer A prepared by radical emulsion polymerization, - where initially in a first stage in aqueous medium a first polymer dispersed in water is prepared by radical emulsion polymerization, the first polymer being prepared from a first composition comprising ethylenically unsaturated radically polymerizable monomers, where the monomers of the first stage comprise at least one monomer having at least one acid group in an amount of at least 0.1 part by weight, based on 100 parts by weight of the total amount of monomers of the first and second stages, and - subsequently in a second stage a polymer dispersion is prepared in aqueous medium and in the presence of the first polymer by radical emulsion polymerization of a second composition comprising ethylenically unsaturated, radically polymerizable monomers, different from the first composition, - where in total less than 0.5 part by weight of emulsifier, based on 100 parts by weight of monomers of the polymer A, or no emulsifier is used, and - where the glass transition temperature of the polymer A prepared is less than 0°C; and - where initially in a first stage in aqueous medium a first polymer dispersed in water is prepared by radical emulsion polymerization, the first polymer being prepared from a first composition comprising ethylenically unsaturated radically polymerizable monomers, where the monomers of the first stage comprise at least one monomer having at least one acid group in an amount of at least 0.1 part by weight, based on 100 parts by weight of the total amount of monomers of the first and second stages, and - subsequently in a second stage a polymer dispersion is prepared in aqueous medium and in the presence of the first polymer by radical emulsion polymerization of a second composition comprising ethylenically unsaturated, radically polymerizable monomers, different from the first composition, - where in total less than 0.5 part by weight of emulsifier, based on 100 parts by weight of monomers of the polymer A, or no emulsifier is used, and - where the glass transition temperature of the polymer A prepared is less than 0°C; and at least one polymer B, in solution in the aqueous polymer dispersion and prepared by radical polymerization of at least one ethylenically unsaturated, radically polymerizable monomer having at least one oxazoline group, and at least 5% by weight, based on the total monomer amount of the polymer B, of at least one hydrophilic, ethylenically unsaturated, radically polymerizable monomer without oxazoline group and with a water solubility of at least 100 g/l at 25°C, and optionally further monomers. at least one ethylenically unsaturated, radically polymerizable monomer having at least one oxazoline group, and at least 5% by weight, based on the total monomer amount of the polymer B, of at least one hydrophilic, ethylenically unsaturated, radically polymerizable monomer without oxazoline group and with a water solubility of at least 100 g/l at 25°C,