Studies On Synthesis And Properties Of Waterborne Acrylic Resin And Waterborne Polyurethane Both Modified By Epoxy Resin

This paper introduced epoxy resin to modify waterborne acrylic resin and waterborne polyurethane. The synthesis and properties of them were studied in detail.Waterborne acrylic resin was modified by grafted copolymerization of acrylic monomer and epoxy resin. The effects of the epoxy value, amount and adding way of epoxy resin, the reaction temperature and the neutralization degree on the properties were investigated. The results showed that after being modified, the water-resistance, hardness, adhesion, tensile strength and impact strength of waterborne acrylic resin were improved. When the amount of E-44 was 6%~9%, the acrylic resin with good properties could be prepared at 110% neutralization degree at 110 ℃ .The structure of product was identified by IR. The shape and side of the waterborne particles were observed by SEM. The thermodynamical behavior was analyzed by DSC.Waterborne aliphatic polyurethane(WPU) dispersion was synthesized by the reaction of epoxy resin with isophorone diisocyanate (IPDI), dimethoxypropionic acid (DMPA) and polyester-diol. The effects of the epoxy value and the amount of epoxy resin, the kind and the amount of the chain-extender and n(NCO)/n(OH) on the properties of WPU were investigated. The results showed that the mechanical properties such as the hardness, adhesion, tensile strength and impact strength of the modified resin were meliorated. when the amount of E-44 was 6%~8%, the amount of EDA was 1%, n(NCO)/n(OH)=(1.5~1.8):1, WPU with good water-resistant, stability and mechanical properties could be prepared. DSC showed the Tg of WPU increased after modified.Zinc-rich coatings were prepared on the base of waterborne epoxy-polyurethane. The electrochemical behavior of the zinc-rich coatings with different amounts of zinc powder in 3% NaCl solution was investigated by corrosion potential test and EIS, and compared with the zinc-rich coating added a little aluminium powder and the traditional epoxy zinc-rich coatings. The results showed that the zinc-rich coatings based on waterborne epoxy-polyurethane had better anticorrosion performance than the traditional coatings. The amount of zinc powder had a certain effect on the anticorrosion performance of coatings, adding a little aluminium powder could improve the anticorrosion performance.