Toward transparent composite films with selective solar spectral, flame retardant and thermal insulation functions

Optical films with high visible (vis) wavelength transparency as well as high ultraviolet (UV) light/high-energy visible (HEV) light/near-infrared (NIR) blocking properties are desired for applications as glass films in building/automotive, and protective films for color printing or culture relics. Herein, the above multi-functions were achieved by preparing the PVC with plasticizer, UV absorbers, pigment yellow and NIR blockers. The prepared transparent films keep high transmittance in visible region (74.53%) and low transmittance in UV region (0.35%), HEV region (52.80%) and NIR region (28.11%). Meanwhile, the flame retardancy was considerably high as verified by its high limiting oxygen index (LOI) value (31%). Moreover, a decrease of about 14.1 °C can also be observed in temperature test using a solar simulator, indicating their outstanding heat insulation/cooling properties. No loss in mechanical performance was observed with the addition of functional additives. All these suggest the potential of using PVC films for outdoor heat-insulation applications.