Study And Application Of UV Electrodeposition Coating

UV curing technology has been developing rapidly for its fast curing rate, energy saving and efficient etc. In this paper, a novel photosensitive waterborne resin for UV curing cathodic electrodeposition coating and electrodeposition photoresist was synthesized by modified with half blocked diisocyanate.In part 1, epoxy acrylic resin for UV curable cathodic electrodeposition coating was synthesized successfully. First, diisocyanate was half blocked by 2-Hydroxyethyl acrylate (HEA) to get prepolymer TDI-HEA. Next, the prepolymer was grafted to the amino epoxy resin (Epoxy-NR3). FTIR result showed that the photosensitive waterborne resin was prepared successfully. Laser light scatter (LLS) characterized the radii of the micelle and its distribution, the result showed the radius was 10~110nm. The characterization results showed this new resin was prepared successfully. The effects of flash off temperature and exposure time on the properties of electrodeposition film were studied. And the results of electrodeposition conditional experiment confirmed that electrodeposite process has important responsibility for ED film properties. The optimum experiment condition was: flash-off T=80℃,time=5min, electrodeposition voltage=80v, time=100s.In part 2, acrylic resin for UV curable cathodic electrodeposition coating has been prepared based on the grafting reaction of cation acrylic resin with half blocked IPDI. And the electrodeposition conditions were studied. The hydrodynamic radii size of colloid particles and its distribution in aqueous solution was measured by Zeta potential and radii size analyzer, and the effect of neutralization degree on colloid stability was investigated. The unsaturated group content and activated monomer have a great effect on the properties of the film, the characteristic results were given in this paper. The effects of flash off temperature and exposure time on the properties of electrodeposition film were studied. And the electrodeposition conditions experiments results confirmed that electrodeposite process has important responsibility for ED film properties. The optimum experiment condition was: flash-off T=80℃, time=10min; electrodeposition voltage=80v, time=90s. The conversion of the resin double bond was studied by FTIR, the result shows that 3%(wt) photoinitiator(PI) dosage and 60s exposure time gave excellent film properties. Also, the technics and properties were compared with marketing ED products.In part 3, acrylic resin for electrodeposition photoresist was synthesized based on the ED coating. The neutralizing degree and Dimethylaminoethyl methacrylate (DMAEMA) content have great effect on the water dispersity and developing property respectively. Optical micrography showed that etching was clear and clean when the DMAEMA content was 13.24%(wt). The change of molecular weight and distribution will result in the change of the pattern resolution. Experimental results confirmed that number average molecular weight range from 25000～35000 could give good pattern. By studying the UV absorption of the mask, complex PI Irgacure907/ITX was choosen. FTIR results revealed that optimum PI dosage was 2.5%(wt) . The effect of the unsaturation content on developing property was studied, and the optimum content was 18.13%(wt).