Method for preparing bottom surface unification cathode electrophoresis dope

Production of cathodic electrophoresis combined with back surface is carried out by: adding into solvent, agitating, heating, dripping into methyl methyl-acrylate monomer and evocating agent solution to obtain cationic acrylic anhydride resin, chain extending for epoxy resin, ring-opening for epoxy resin by ammonia and ketoimine, preparing isocyanate in semi-closed environment, graft reacting, preparing cross-linking agent, preparing half-finished product into emulsion and color paste and coating. It costs low, has less energy-resource consumption and VOC discharge, and shorter process flow path. It can be used to coat chassis of vehicles, work pieces, toys, light ornaments and hardware products.