Synthesis and properties of waterborne coatings based on modified epoxy resins

摘要

Waterborne epoxy resins have been developed in order to meet environmental regulations for reduction of the emission of organic solvents from coatings. A major type of waterborne epoxy resins are based on the use of non-ionic surfactants for dispersion of epoxy resins in water. These dispersions can be obtained by the use of conventional surfactants as well as reactive surfactants. Recent work in our laboratories has focused on modifications of epoxy resins based on proprietary surfactants in order to develop new waterborne epoxy resins for applications in ambient-cure and bake coatings. Two-component, ambient-cure coatings have been formulated from waterborne epoxy resins and curing agents. Water-dispersible polyamines and acrylic resins have been used as curing agents for these coatings. Waterborne epoxy resins for formulation of bake coatings with phenolic resins, amino resins or dicyanamide as curing agents have been developed. Epoxy resins have been modified with proprietary surfactants and drying oil fatty acids to obtain waterborne epoxy esters for air-drying and bake coatings. Waterborne epoxy resins with very low solvent content have been developed which are being explored for the formulation of coatings with low solvent emissions.