TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The layer (Y) is vapor deposited-layer of aluminum, or vapor deposited-layer of aluminum oxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The layer (Y) is a layer (YA) including reaction product (R) which is formed by reacting metal oxide (A) and phosphorus compound (B) containing aluminum. The metal oxide (A) is hydrolysis-condensation product of compound (L) containing metal atom (M). The compound (L) contains compound (L1) of formula: AlX1mR1(3-m) (II), preferably aluminum triisopropoxide and/or aluminum tri sec-butoxide. The phosphorus compound (B) is phosphoric acid, polyphosphoric acid, phosphorous acid and/or phosphonic acid, or their derivatives.X1=fluoro, chloro, bromo, iodo, R2O-, R3C(=O)O-, (R4C(=O))2CH- or NO3;R1-R4=alkyl, aralkyl, aryl or alkenyl;andm=1-3.Preferred Process: The ratio of number-of-moles of metal atom (M) with respect to number-of-moles of phosphorus atom derived from phosphorus compound (B) in layer (YA) is 1-3.6.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The multilayered-structure base-material (X), layer (Y) and layer (Z), laminated in order. The polymer (E) is poly(vinylphosphonic acid) of formula (I). The base-material (X) contains thermoplastic resin film layer, paper layer, and inorganic vapor deposited-layer.n=1 or more.Preferred Properties: The oxygen permeability of multilayered-structure at 20 degrees C under 85 %RH condition is 2ml/(m2.day.atm) or less. The oxygen permeability of multilayered-structure after stretching at 23 degrees C under 85 %RH condition for 5 minutes is 2ml/(m2.day.atm) or less. The maximum infrared absorption wave number of layer (YA) is 1080-1130 cm-1 at a wavelength of 800-1400 cm-1 based on infrared absorption spectrum. The ratio of light-absorbency in maximum infrared absorption wave number of layer (YA) with respect to light-absorbency in maximum infrared absorption wave number of layer (YA) after stretching vibration of hydroxyl group at a wavelength of 2500-4000 cm-1 is 0.2 or less, based on infrared absorption spectrum. The half value width of multilayered-structure at absorption peak is less than 200 cm-1. Preferred Process: A precursor layer of layer (YA) is formed by applying a coating liquid (U), on base-material (X), heat-processing at 110 degrees C or more, and forming layer (YA). The coating liquid (U) is prepared by reacting a compound with metal oxide (A) and solvent.