TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Oxide: The inorganic oxide is silicon oxide of formula SiOx, where x = 1.7-1.9.Preferred Structure: The moisture resistant film comprises anchor coat layer interposed between base film and deposited layer of inorganic oxide. The back cover material has adhesive layer disposed on one surface.Preferred Properties: The back cover material has moisture permeability of 1 g/m2/day or less. The thickness of anchor coat layer is 0.01-1 mum; thickness of base film is 3-300 mum, preferably 5-200 mum; and thickness of deposited inorganic oxide layer is 100-500 Angstrom.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The anchor coat layer is made of acrylic resin, polyester resin, alkyd resin, urethane alkyd resin, polyamide resin, polyurethane resin or phenolic resin, preferably acrylic urethane resin. The base film of moisture resistant film is made of fluororesin, polyester, polycarbonate, polymethyl methacrylate or polyamide. The adhesive layer is made of ethylene vinyl alcohol resin, polyvinyl butyral resin, silicone resin, acrylic resin, butyl resin or epoxy resin. The heat resistant film, moisture resistant film and weather resistant film are bonded using hydrogenated polybutadiene denatured urethane adhesive. EXAMPLE - Moisture resistant film comprising acrylic urethane resin (anchor coat layer) of thickness 0.1 mum interposed between polyethylene terephthalate of thickness 12 mum and layer of deposited silicon oxide of thickness 200 Angstrom, was formed. The moisture resistant film was placed between polyester film mixed with white pigment and 2-ethylene-4-fluoroethylene copolymer (ETFE) film (thermal and weather resistant films). The films were bonded by dry lamination at 60-90degreesC with 3 kg of nip pressure using acrylic urethane adhesive. The back cover material thus formed was left aside for 1000 hours at 85degreesC and 90% relative humidity, and tested for air permeability. The back cover material was found to have air permeability of 0.2 g/m/day, after 1000 hours at 40degreesC and 90% relative humidity