TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compound: The dialkoxysilane is chosen from 3-aminopropyl-alkyl-dialkoxysilane and/or N-2-(aminoethyl)-3-aminopropyl-alkyl-dialkoxysilane.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: The surface of back-sheet base material is chemically treated by coating urethane resin-type coating agent. The physical treatment is corona treatment. Preferred Components: The urethane resin-type coating agent is two-liquid reaction-type adhesive composition containing polyester urethane polyol as main component and hardening agent containing isocyanate compound. The copolymer of polar monomer and ethylene is chosen from ionomer of ethylene and unsaturated-carboxylic-acid copolymer and/or ethylene and unsaturated-carboxylic-acid copolymer. The ethylene and unsaturated-carboxylic-acid copolymer is ethylene-acrylic acid copolymer or ethylene-methacrylic acid copolymer. The ionomer of ethylene and unsaturated-carboxylic-acid copolymer is zinc ionomer of ethylene and unsaturated-carboxylic-acid copolymer. The fluororesin is chosen from tetrafluoroethylene ethylenic copolymer, tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, polychlorotrifluoroethylene resin, chlorotrifluoroethylene ethylenic copolymer, polyvinyl fluoride and/or polyvinylidene fluoride. The polyester resin is chosen from polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and/or polycyclohexane dimethanol terephthalate. Preferred Composition: The content of dialkoxysilane is 15 mass parts or less, preferably 0.03-12 mass parts with respect to 100 mass parts of copolymer of polar monomer and ethylene. The content of structural unit derived from unsaturated carboxylic acid of ethylene and unsaturated-carboxylic-acid copolymer is 20 mass% or less with respect to total mass of copolymer. Preferred Property: The neutralization degree of acidic radical in the ionomer of ethylene and unsaturated-carboxylic-acid copolymer is 60% or less.