A coating apparatus for applying plastic coatings onto a planar substrate includes an elongate coating head defining therein an elongate distribution channel having a length corresponding to a width of a substrate to be coated, the coating head also defining a coating gap for discharging a coating material from the distribution channel. First and second supply channels are respectively connected between respective pumps and different portions of the distribution channel for respectively supplying first and second coating materials to the distribution channel. A mixing zone is formed in the distribution channel by a partition or a hollow conical body, each of which forms a mixing gradient extending along the length of the mixing zone. Ideally, the pumps for the first and second coating materials provide these materials with the same pressure within the mixing zone.