TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The heat stabilizer is chosen from calcium-zinc complex, barium-zinc complex and rare-earth compound.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The content of silane coupling agent, crosslinking curing agent, crosslinking curing accelerator, heat stabilizer, tackifier, antioxidant, ultraviolet absorber and light stabilizer contained in the film is 0.1-1.5 parts, 1.9-2.1 parts, 0.15-0.2 part, 2-4 parts, 0.4-0.5 part, 0.5-0.7, 0.06-0.08 part and 0.05-0.1 part, respectively. The silane coupling agent is chosen from 3-aminopropyl methyldiethoxysilane, 3-aminopropyl trimethoxysilane, N-(2-aminoethyl)-3-aminopropyl methyldimethoxysilane, 3-glycidol propoxy dimethylethoxysilane, 3-epoxy propoxy propyl trimethoxysilane, 2-(3,4-epoxy cyclohexyl)ethyl trimethoxysilane and gamma -(methacryloxy)propyl trimethoxysilane. The crosslinking curing agent is chosen from 2-ethylhexyl carbonate, 2,5-dimethyl-2,5-di(tert-butyl peroxy)hexane and 1,1-(diperoxy tert-butyl)-3,3,5-trimethylcyclohexane. The crosslinking curing accelerator is chosen from triallyl isocyanurate, triallyl cyanurate and trimethylolpropane methyltrimethacrylate. The tackifier is gamma -glycidol ether propyl trimethoxysilane, gamma -aminopropyl triethoxysilane or vinyl trimethylsilane. The antioxidant is chosen from octadecyl beta -(4-hydroxy-3,5-di-tert-butyl phenyl)propionate, N,N'-1,6-dihexyl di(3,5-di(1,1-dimethyl ethyl)-4-hydroxybenzene)propioniate, di(2,4-dimethylbenzyl)pentaerythritol diphosphite ester, distearyl pentaerythritol diphosphite ester and tri(nonyl phenyl)phosphite ester. The hindered amine light stabilizer is (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyl ethyl)polysuccinate or bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate. The ultraviolet absorber is chosen from nanotitanium oxide, nanoaluminum oxide, 2-hydroxy-4-n-dodecyloxy benzophenone, 2-hydroxy-4-n-octylphosphine benzophenone and 2-(2'-hydroxy-3',5'-ditert-butyl)-5-chlorobenzotriazole.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The content of vinyl acetate contained in the ethylene-vinyl acetate copolymer is 34-37%. Preferred Property: The ethylene-vinyl acetate copolymer has melt index value of 50 g/10 minutes.