基于氨基树脂-环氧树脂交联固化体系的无皂苯丙树脂性能研究OA

A stable styrene-acrylic emulsion with high hydroxyl content was successfully synthesized via soap-free emulsion polymerization.A dual cross-linking system was constructed by incorporating epoxy resin E-51 and amino resin,with systematic investigation on the performance optimization mechanism of cross-linked films.The self-emulsification was achieved through water-soluble monomers including acrylic acid,methacrylic acid,and poly(ethylene glycol)methyl ether methacrylate.By choosing the soft/hard monomer ratio(mbutyl acrylate∶mstyrene=1∶2),the theoretical glass transition temperature of copolymer reached 45 ℃.Experimental results demonstrated that when the mass curing ratio of epoxy resin E-51 to styrene-acrylic emulsion was 20∶1,the cross-linked film exhibited optimal comprehensive performance with continuous and compact surface morphology.Under this condition,pencil hardness significantly improved to 5 H,dry/wet adhesion enhanced to grade 0.24-hour water absorption rate decreased to 2.5％,representing 66.6％reduction compared to epoxy-free system.The corrosion potential elevated to-0.079 V and the corrosion current density reduced to 9.2 × 10-4 mA/cm2.The tensile strength reached 1.8 MPa,increasing by 137％.The initial decomposition temperature rose to 235.7 ℃.The synergistic cross-linking between amino resin and epoxy resin,through ring-opening reactions of epoxy groups with carboxyl groups and etherification of alkoxy groups with hydroxyl groups,effectively reduced hydrophilic groups and formed a dense network structure.This mechanism significantly enhanced the chemical resistance and mechanical properties of the coating,thus providing novel insights for developing high-performance environmentally friendly water-based metal baking paints.