Preparation of Epoxy Modified Organosilicone High-Temperature Resistance Coatings

An ambient-cured organosilicone resin modified with epoxy resin was synthesized with lab-synthesized polysiloxane resin and biphenix-A epoxy resin(E-20) by copolymerization at 180~190 °C for 2~3 hours. The effect of ratios between polysiloxane resin and E-20, reaction temperatures and reaction time on heat resistance and miscibility etc were discussed in detail. The experiment results showed that the epoxy modified organosilicone resin exhibited the best solubility performance and adhesion strength when the ratio of the polysiloxane resin to E-20 was 3:7. The Fourier transform infrared spectra (FTIR) revealed that hydroxy on epoxy resin had reacted with ethyoxyl on organic silicon molecular chain, but no ring-opening reaction happened on epoxy group of E-20. The excellent high-temperature resistance painting, based on these epoxy modified organosilicone resin was prepared with flake aluminum powder as temperature resistance filler, polyamide 650 as curer and WD-50 coupling agent as curing-promoter. It was shown that the temperature resistance was superior to 600°C and the adhesion strength of the coating was up to 1 grade. Scanning electron microscope(SEM) revealed the reaction happened on -Si-O-Si- and Al under high temperature improved the coatings to resist higher temperature. The mechanism of the high-temperature anticorrosion is attributed to “ring-opening reaction” and “cross-link solidification reaction”.