NOVELTY - A multilayer backsheet (1) comprises first outside layer (2), second outside layer (3) and inside layer (4, 5) which is arranged between the outside layers and forms a water-vapor barrier and/or oxygen barrier, where the layers are composed of polymers, and the two outside layers comprises a polyamide, and at least one inside layer consists of polymers other than fluoropolymers/polyethylene, where inside layers made of partly aromatic polyesters are connected by at least one outer adhesion promoter layer (6) made of block copolyesteramide.    USE - As multilayer backsheet for a photovoltaic module (claimed).    ADVANTAGE - The multilayer backsheet has improved water-vapor and oxygen barrier effect. The multilayer backsheet meets all relevant requirements such as weathering stability (UV and hydrolysis resistance), heat resistance, mechanical protection, electric insulation, high reflectivity and good adhesion. The reflectivity of multilayer backsheet with white pigment is at least 92%.    DETAILED DESCRIPTION - A multilayer backsheet (1) comprises a first outside layer (2), a second outside layer (3) and at least one inside layer (4, 5), which is arranged between these outside layers and forms a water-vapor barrier and/or oxygen barrier, where the layers are composed of polymers, in which at least one of the two outside layers comprises a polyamide, and at least one inside layer consists of polymers which are not fluoropolymers and do not comprise any polyethylene, where inside layers made of partly aromatic polyesters are connected by means of at least one outer adhesion promoter layer (6) made of block copolyesteramide, and at least one of the outside layers comprises a polyamide. An INDEPENDENT CLAIM is included for producing multilayer backsheet which comprises a first outside layer and a second outside layer and at least one inside layer, which is arranged between these outside layers and forms a water-vapor barrier and/or oxygen barrier, where at least one of the two outsides layers is formed by a polyamide, and at least one inside layer is formed by a polymer which is not fluoropolymer and does not comprise any polyethylene, where inside layers made of partly aromatic polyesters are used only in combination with an outer adhesion promoter layer made of block copolyesteramide.    DESCRIPTION OF DRAWING(S) - The figure shows a multilayer backsheet for a photovoltaic module.    Multilayer backsheet (1)    First outside layer (2)    Second outside layer (3)    Inside layer (4,5)    Outer adhesion promoter layer (6)    Inside adhesion promoter layer (7, 9)