TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The nanopowder is mixture of inorganic micro-nanosized powder and coupling agent covered silicon dioxide nanopowder. The weight percentage of coupling agent covered silicon dioxide nanopowder is 0.5-2%, and rest is inorganic micron-nanosized powder. The inorganic micro nanosized powder is mixture of zirconium oxide, aluminum oxide and boron nitride. The silicon dioxide nanopowder is covered with coupling agent (0.5-1 wt.%) that is any one of organic silicon, titanate and aluminate. The PET layer is co-extrusion structure of 3 layers A, B and C, which is entirely 160-280, preferably 200-245 mu thick. The layer A is PET mixcrystal layer (20% of thickness of PET layer). The layer B is nano-layer (60% of thickness of PET layer). The layer C is flame retardant layer (20% of thickness of PET layer). The nano-layer B is made from mixture of silicon dioxide, titanium dioxide, aluminum oxide and zinc oxide. The 4 layers are treated through plasma titanium silicide nano-treatment process and the coating of first high fluoro-mixcrystal coating, PET layer and second high fluoro-mixcrystal coating is carried out. During coating, corrugation-free coating technique of high-precision coating production line is adopted and high fluoro-mixcrystal paint is applied to PET thin sheet in a roller coating manner.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The first high fluoro-mixcrystal coating or second high fluoro-mixcrystal coating is formed from mixture of nanopowder (0.1-1, preferably 0.3-0.8 wt.%), modified difluoro-paint (0-35m, preferably 25-35 wt.%) and trifluorovinyl paint (55-85, preferably 60-70 wt.%). The grain diameter of mixcrystal paint is 5-15, preferably 5-10 mu m. The first high fluoro-mixcrystal coating and second high fluoro-mixcrystal coating are 15-35, preferably 22-28 mu m. The first base layer, second base layer, third base layer and fourth base layer are 1-30, preferably 6-12 nm thick. The high fluoro-mixcrystal paint coating speed is 10-30 (preferably 15) m/minute, where coating thickness is 15-35 (preferably 20-25) mu m, curing temperature is 120-140 (preferably 135) degrees C, enclosed isocyanate is employed as curing agent and de-enclosing temperature is 80-140 (preferably 90-100) degrees C.