Study On Structure And Lifetime Of PVC Protective Membrane

The protective membrane is one kind of membrane materials that coated on the surface of plastic door and window, which can absorb and stop energy of UV light, protecting plastic door and window from the destruction of UV light.Its main raw material is polyvinyl chloride. As plastic door and window industry is developing rapidly in recent twenty years in China, PVC protective membrane has a huge market and bright prospects. This paper presents a composite structure that consists of a poly(methl methacrylate) resin surface layer and a PVC resin base layer, and studies on its formula, function, preparation process and life. The main work is as follows:1. In preparation process of PVC base layer, three different formulas were designed, and vinyl chloride(VC)-acrylate(BA)-vinyl acetate(VAc) terpolymer resin were used as a plasticizer of PVC resin. After thermal property test of VC-BA-VAc resin, two different preparation process were developed, mill process and extrusion process. The extrusion process was chosen as the better method. The extrusion process was:using a screw with 3:1 compression ratio, the extruder barrel and mold temperature were 100℃,130℃,160℃,165℃ and 160℃; then casting membrane by using a screw with 2:1 compression ratio, extruder barrel and adapter temperature were 100℃,130℃,160℃,170℃ and 165℃, the casting mold temperature was 170℃.2. In PMMA/PVC protective membrane formula and preparation process research, we cast three kinds of PVC membrane samples which respectively containing 40phr,50phr and 60phr VC-BA-VAc resin by solution and extrusion process, and got six kinds of samples. After 600h aging test, considering appearance, performance, cost and environmental protection and other factors, we chose 50phr as the best content and extrusion process as the preparation process,3. In PMMA/PVC protective membrane lifetime research, we ran a 1200h UV accelerated aging experiment and observed the aging degree of samples by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and mechanical properties test. Finally, after fitting the relationship between mechanical property retention and aging time, we predicted the lifetime of PMMA/PVC protective membrane was more than 1721h under the experiment conditions of this paper.