TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The curing agent is a compound that can react with epoxy group or hydroxy group. The compound which can react with the epoxy group is an amine compound, an acid anhydride compound, a phenol compound or an imidazole compound. The compound capable of reacting with hydroxy group is an isocyanate compound or an urea-based compound. The imidazole compound is of formula (I).R2, R4, R5 = not defined.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The weight-average molecular weight of the bisphenol-A type epoxy resin is 200-10000. The content of the bisphenol-A type epoxy resin is 5-30 pts. wt., based on 100 pts. wt. phenoxy resin. The phenoxy resin comprises bisphenol A type phenoxy resin, bisphenol F type phenoxy resin, brominated phenoxy resin, phosphorus based phenoxy resin, bisphenol A type/bisphenol S-type phenoxy resin and caprolactone modified phenoxy resin or siloxane modified phenoxy resin. The weight-average molecular weight of phenoxy resin is 1000-100000. The phenoxy resin includes epoxy, hydroxy, amine, fluoride, siloxane or amide terminal group. The phenoxy resin comprises melamine cross-linking agent, urea-formaldehyde, isocyanate functional prepolymer, phenolic hardener or amino based curing agent. Preferred Method: The plastic film is formed by solvent casting or melt extrusion method using composition comprising bisphenol-A type epoxy resin, phenoxy resin and curing agent or coating a thin film to thick film on a transparent polymer substrate made of polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyether sulfone or polyimide, where the coating thickness is 0.1-500 mu m. EXAMPLE - 100 g Phenoxy resin YP50 was dissolved in 300 g methyl ethyl ketone, mixed with 15 g isocyanate thermal curing agent CE138 and stirred for more than 1 hour. Then 10 g bisphenol-A type epoxy resin YD-128 and 0.5 g 2-phenylimidazole were added to the obtained composition and stirred for 2 hours. The obtained composition was coated on XD5BR (RTM: Release film), dried for about 3 minutes at 150 degrees C, release film was removed to obtain film of 30 mu m thickness, dried at 200 degrees C, pressed with polyethylene terephthalate and post cured at 60 degrees C to obtain the plastic film.