Synthesis Of Silicon Fluoride Modified Acrylic Resin And Its Application In Cathodic Electrophoretic Coatings

Cathodic electrodeposition paint(CEDP) was environmental and friendly water-based coating which was mainly formed of cationic resin and painted by electrophoretic deposition. Moreover, the advantage of this coating strategy was film uniformity, low pollution, resource-saving and high-safety factor. Therefore, it was widely applied for auto-mobile, industrial products, electromechanical products, hardware and building material, and et al.Acrylic resin showed excellent weatherability, high decorative and high gross, which was widely used for cathodic electrodepositon paint. In this paper, cation acrylic resin was synthesized, moreover, we also used silicone and fluorine modified the cation acrylic resin in order to improving heat resistance, corrosion resistance and the resistance of water and oil,.In this paper, cationic acrylic ester(PA) was synthesised by methyl methacrylate(MMA), butyl acrylate(BA), 2-hydroxyethyl methacrylate(HEMA), 2-(dimethylamino)ethyl methacrylate(DMAEMA), isobornyl methacrylate(IBMA) and N-isobutoxymethyl acrylamide(N-IBAM) through solution polymerization. FT-IR analysis confirmed that all the monomer was underwent polymerization. The optimal sythesised conditions for the 65% solid content was cofirmed: the dosage of the polymerization initiators was 1.25wt%, the reaction temperature and time was 95±1? and 5h respectively, the content of the DMAEMA and HEMA was repectively confimed 15wt% and 13wt%, and lactic acid was also chosen as the neutralizing agent with 90% neutralization degree. For the CEDP, MEKO blocked HDI trimer was selected as the crosslinking agent and the best ratio of n(-OH): n(-NCO) was also cofirmed to 1: 1.1. In this condition, the particle size for CEDP was 9.39 nm with good storage stability. The hardness, the flexibility, adhesion and the impact resistance was 3H, 0mm, 0 level and 50Kg·cm.On the basis of PA fomulation, Tri(isopropoxy)vinylsilane(TIVS) was selected by grafting with the acrylic ester. FT-IR analysis confirmed that SPA was sythesised with TIVS grafting in PA. Different content of the TIVS was studied and the result was showed as following: the perfect properties for the SPA and CEDP were achieved when the additive amount of TIVS was 9wt%. In this conditon, the dynamic viscosity of SPA was 27.45Pa·s and the paticle size of CEDP was 12.7nm. It was showed good hydrophobic with 0.943% water absorption, 101.27°water contact angle and 89.3°diiodomethane contact angle, and good acid/alkali resistance was also showed in the testing.On the basis of SPA fomulation, 2-(Perfluoroalkyl) ethyl methacrylate(FEMA) and TVIS were chosen by grafting with the PA. FT-IR analysis confirmed that SFPA was sythesised with FEMA and TVIS grafting in PA. Different content of the FEMA(based on 9wt% TIVS content) was studied and the result was showed as following: the perfect properties for the SFPA and CEDP were achieved when the additive amount of FEMA was 9wt%. It showed better hydrophobic with 106.4°water contact angle and 96.3°diiodomethane contact. Greater enhancement in the heat-resistance of the CEDP was indicated from TG and DTG curve. In addition, excellent corrosion-resistance was also exhibited in the experiments.The optimized composition with PA, SPA and SFPA were taken for example by analysing the impact of the electrodeposition process on the thickness and the coating appearance. The optimized electrodeposion conditions were confirmed: the electrophretic voltage was 40 V, the time was 50 s and the temperature was 30 oC. In this conditon, the appearance of coating was good and uniform thickness.