Abstract: Use and process for manufacture of a multilayer film with a longitudinal and transverse direction, comprising: (a) a base layer; (b) a coating layer comprising a soluble polymer, pigment and/or dye, wherein the composition and/or concentration of the pigment and/or dye varies in the direction parallel to the film surface; and (c) a sealing layer.

Abstract: In a process for the welding of plastic films lying flat, one on top of the other, the plastic films are brought into contact with a heated cutting edge and hot-tool welded. Two-layered or multilayered composite films of different chemical composition are used for the welding; for example, one composite film can be an opaque, colored or uncolored layer, on which there is arranged a transparent sealing layer comprised of a propylene-ethylene copolymer or a propylene-ethylene blend. The sealing layer of the opaque composite film is welded directly to a sealing layer of a second, transparent composite film.