Research And Synthesis Of Resin For Cathodal Electrophoretic Coating

Two type of cationic resins for cathodal electrophoretic coating were synthesized by free radical solution polymerizationxationic acrylic resin and acrylate copolymer modified by organo-silicone; the acrylic grafted epoxy resin were synthesized via grafting copolymerization.The acrylate resin and organo-silicone-modified acrylic resin were synthesized by copolymerization with dimethylaminoethyl methacrylate (DMAEMA), hydroxyethyl methacrylate(HEMA), organo-silicone etc. The acrylate polymer and acrylate copolymer modified by organo-silicone were synthesized by using the batch, semi-continuous and continuous monomer adding processes. The results of copolymerization processes, particle morphology and copolymer stability showed that the batch process was the best one to obtain the stable copolymer. The factors of affects on the resin water-solubility and properties of coatings were studied, and the particle size and its distribution, the absorptivity of water, acid- and base-resistance and heat-stability were investgated. Structures and properties of the polymers were characterized by means of Fourier Transform Infrared Spectrum (FTIR), Transmission Electron Microscopy(TEM), Differential Scanning Calorimetry(DSC) and Thermogravimetry(TG). The results indicated that the organo-silicone has copolymerized with acrylate, by which water-resistance and heat-stability of the film of the coating were improved, compared with the film based on the pure acrylate coating, and many properties have been greatly improved, for example acid- and base-resistance.The copolymer resins were synthesized by grafting acrylic polymer onto epoxy resin. The self-crosslinked acrylate grafted epoxy resins forcathodal electrophoretic coating were synthesized by appropriate monomers. Effects of the types of epoxy resin, the reaction temperature, the reaction time and appropriate solvents on the stability, dispersibility and other properties of the copolymer were discussed. The structures of the polymers were characterized by means of FTIR and DSC. The results showed the vinyl silane and acrylic polymeric blanch are incorporated with epoxy resin by chemical bonds. The heat-resistance of the polymer was characterized by TG, and the result indicated that heat-stability has been improved via grafted copolymerization.