TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The content of additive, titanium pigment and zinc oxide is 8 parts mass, 6 parts mass and 2 parts mass. The thickness of the upper layer film is 10-500 mu m, preferably 100 mu m and the thickness of the lower layer film is 20-500 mu m, preferably 450 mu m.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The upper layer film or lower layer film further contains a light stabilizer. The peroxide is chosen from 9 compounds e.g. di-tert-butyl peroxide, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, dicumylperoxide, t-butylperoxybenzoate and t-butylperoxy-2-ethylhexyl monocarbonate. The auxiliary crosslinking agent is chosen from trimethylolpropane triacrylate, trimethylolpropane trimethylacrylate, N,N'-phenylene bismaleimide and triallyl isocyanate. The silane coupling agent is gamma -methacryloxypropyl trimethoxysilane. The antioxidant is chosen from pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and 2,6-di-t-butyl-4-methylphenyl isodecyl pentaerythritol diphosphite. The light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.The upper film layer comprises 100 parts mass ethylene-vinyl acetate resin, 1.2 parts mass t-butylperoxy-2-ethylhexyl monocarbonate, 0.6 part mass trimethylol propane trimethacrylate, 1 part mass gamma -methacryloxypropyl trimethoxysilane, 0.8 part mass bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate and 0.8 part mass pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate). The lower film layer comprises 100 parts mass ethylene-vinyl acetate resin, 1.2 parts mass t-butylperoxy-2-ethylhexyl monocarbonate, 0.6 part mass trimethylol propane trimethacrylate, 6 parts mass titanium dioxide, 2 parts mass zinc oxide, 0.8 part mass bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate and 0.8 part mass pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).