TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The fluoropolymer is selected from fluoroethylene homopolymer, 1,1-difluoroethylene homopolymer, 1,2-difluoroethylene homopolymer, fluoroethylene/non-fluorinated 2-4C mono-olefin copolymer, 1,1-difluoroethylene/non-fluorinated 2-4C mono-olefin copolymer, hexafluoropropylene/fluoroethylene copolymer, hexafluoropropylene/1,1-difluoroethylene copolymer, hexafluoropropylene/1,2-difluoroethylene copolymer, tetrafluoroethylene/fluoroethylene copolymer, tetrafluoroethylene/1,1-difluoroethylene copolymer, tetrafluoroethylene/1,2-difluoroethylene copolymer, trifluorochloroethylene/fluoroethylene copolymer, trifluorochloroethylene/1,1-difluoroethylene copolymer, trifluorochloroethylene/1,2-difluoroethylene copolymer, or a blend of two or more of the above polymers or copolymers. Preferably, the fluoropolymer is selected from polymers or copolymers containing monomer units derived from hexafluoropropylene, tetrafluoroethylene and trifluorochloroethylene. The polyester film comprises poly 2-6C alkyl benzenedicarboxylate. The polyester is selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyethylene phthalate, polytrimethylene phthalate, polybutylene phthalate, polyhexamethylene phthalate or a copolymer or blend of two or more of the above. The ethylene copolymer is selected from ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-propyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-propyl acrylate copolymer, ethylene-butyl acrylate copolymer or a blend of two or more of them in any ratio. It comprises an ethylene copolymer formed by ethylene and one or more co-monomers, the co-monomer being selected from methyl methacrylate, methyl acrylic ester, ethyl methacrylate, ethyl acrylic ester, propyl methacrylate, propyl acrylic ester, butyl methacrylate, butyl acrylic ester, methacrylic acid glyceride, methyl hydrogen maleate, ethyl hydrogen maleate, and maleic anhydride. The ethylene copolymer is selected from ethylene-(meth)acrylate-(meth)acrylic acid terpolymers, ethylene-(meth)acrylate-glycidyl methacrylate terpolymers, and ethylene-alkyl (meth)acrylate-maleic anhydride terpolymers. One or more metallic layers, metal oxide layers or non-metal oxide layers are adhered to one or two surfaces of the polyester film and/or fluoropolymer film. The one or two main surfaces of the polyester film and/or fluoropolymer film have one or more oxide layers adhered thereto, the oxide layers selected from silicon oxide layers having the general molecular formula SiOx, x=1-2 and aluminum oxide layers having the general molecular formula AlOx, x=0.5-1.5. One or two main surfaces of the polyester film and/or fluoropolymer film are laminated with one or more metallic layers selected from silver foil, aluminum foil, tin foil and copper foil. The solar panel back sheet further comprises a second extruded adhesive layer on the surface of the stretched polyester film that is opposite of the fluoropolymer film, the second extruded adhesive layer comprised of at least 70% by weight of copolymer of ethylene and one or more monomers selected from 1-4C alkyl acrylates, 1-4C alkyl methacrylates, methacrylic acid, acrylic acid, glycidyl methacrylate, maleic anhydride and copolymerized units of ethylene and a comonomer selected from 4-8C unsaturated anhydrides, monoesters of 4-8C unsaturated acids having at least two carboxylic acid groups, diesters of 4-8C unsaturated acids having at least two carboxylic acid groups and mixtures of such copolymers, where the ethylene content in the ethylene copolymer accounts for 60-90% by weight, preferably accounting for 65-85% by weight, and ideally accounting for 70-80% by weight. It comprises a second fluoropolymer film adhered to the second extruded adhesive layer; and a metal foil adhered to the second extrude adhesive layer, and further comprising further comprising a third extruded adhesive layer on the surface of the metal foil that is opposite of the stretched polyester film, the third extruded adhesive layer comprised of at least 70% by weight of copolymer of ethylene and one or more monomers selected from 1-4C alkyl acrylates, 1-4C alkyl methacrylates, methacrylic acid, acrylic acid, glycidyl methacrylate, maleic anhydride and copolymerized units of ethylene and a comonomer selected from 4-8C unsaturated anhydrides, monoesters of 4-8C unsaturated acids having at least two carboxylic acid groups, diesters of 4-8C unsaturated acids having at least two carboxylic acid groups and mixtures of such copolymers, where the ethylene content in the ethylene copolymer accounts for 60-90% by weight, preferably accounting for 65-85% by weight, and ideally accounting for 70-80% by weight. Preferred Method: Polyester film undergoes mono-axial or biaxial stretching, with a longitudinal stretch ratio of 2-4 times and transverse stretch ratio of 2-4 times. Manufacturing back sheet material further comprises: (e) providing a second copolymer of ethylene and one or more monomers selected from 1-4C alkyl acrylates, 1-4C alkyl methacrylates, methacrylic acid, acrylic acid, glycidyl methacrylate, maleic anhydride and copolymerized units of ethylene and a comonomer selected from 4-8C unsaturated anhydrides, monoesters of 4-8C unsaturated acids having at least two carboxylic acid groups, diesters of 4-8C unsaturated acids having at least two carboxylic acid groups and mixtures of such copolymers, where the ethylene content in the second ethylene copolymer accounts for 60-90% by weight, preferably accounting for 65-85% by weight, and ideally accounting for 70-80% by weight; and (f) extruding an adhesive layer comprised of at least 70% by weight of the ethylene copolymer of step (e), based on the weight of the adhesive layer, at a temperature of 270 degrees C or higher on an exposed surface of the stretched polyester film of the fluoropolymer/ethylene copolymer/stretched polyester multilayer laminated film of step (d).