Abstract: The invention provides an adhesion promoter composition comprising at least one polymer A selected from at least one epoxy resin-phenol resin precondensate, a mixture of at least one epoxy resin-phenol resin precondensate and epoxy resins, a mixture of epoxy resins and phenol resins, polyamide resins and mixtures thereof, and at least one copolyamide-based hotmelt adhesive. Additionally described is a primer composition comprising at least one polymer B selected from saturated polyester resins, epoxy-phenol resin precondensates, mixtures of epoxy resins and phenol resins, and mixtures thereof, at least one crosslinker resin selected from the group consisting of melamine resins, blocked isocyanate resins and mixtures thereof, at least one catalyst, and at least one copolyamide-based hotmelt adhesive.