LAMINATE

PROBLEM TO BE SOLVED: To improve the close adhesiveness between a base material and a sealing material by allowing a gas barrier layer formed in turn of a polymer molded item, silicon dioxide, silicon nitride, or a mixture of silicon dioxide and silicon nitride to be surface-treated by the agency of plasma containing metal. SOLUTION: A gas barrier layer 20 consisting of silicon oxide or silicon nitride, or a mixture of them is formed on at least one surface of a polymeric molded body 10. For such a method of the formation, a physical deposition method, a moisture method, a chemical vapour growth method and the like are employed. A surface treatment is carried out on the surface 21 of the gas barrier layer 20 by plasma containing metal. The superficial treatment containing metal referred to therein is achieved by permitting the gas barrier layer to be exposed on the metal-containing plasma. The metal containing plasma is obtained, e.g. by the steps of introducing discharging gas, generating plasma by DC glow discharge or RF glow discharge, and conducting evaporated particles of evaporated metal in the vacuum device by an electron beam or the like.