Introduction: Waterborne epoxy ester anticorrosive coatings that “cure without a hardener—they dry on their own”
Two-component waterborne epoxy (epoxy emulsion + waterborne amine curing agent) offers excellent performance but has three major pain points: Pot Life limitation (2-6h——must be used up after mixing), difficulty in low-temperature curing (<10°C——extremely slow reaction), and complex application (on-site mixing/induction waiting). Waterborne epoxy ester——esterifies epoxy resin with fatty acids (soybean oil/linseed oil/tall oil)——introduces C=C unsaturated double bonds onto the epoxy backbone——after coating, water evaporation + O2 in air + drier——autoxidative crosslinking——forms a solid coating no amine curing agent needed “single-component——ready to use out of the can——infinite Pot Life——dries even at 0°C” is the “light corrosion protection——affordable——convenient” best choice.
Waterborne epoxy ester coating is an epoxy resin modified by fatty acid esterification—introducing C=C unsaturated double bonds—using water as the medium—catalyzed by metal driers (manganese/iron/vanadium composite—replacing carcinogenic cobalt) to induce autoxidative crosslinking between O2 in the air and C=C—forming a dense coating—combining the adhesion/chemical resistance of epoxy with the autoxidative air-drying properties of alkyd—VOC500-1000h—suitable as a single-component waterborne anti-corrosion primer for C2-C3 corrosive environments.
FAQ
Q1: What is the chemical principle behind the “dual identity” of epoxy ester—possessing both the adhesion of epoxy and the air-drying property of alkyd?Epoxy resin provides the bisphenol A skeleton (rigidity/adhesion/chemical resistance)—fatty acid provides C=C double bonds (can auto-oxidatively crosslink). Epoxy + fatty acid → esterification reaction → the “epoxy ester” molecule—one end—is—the epoxy—skeleton—(provides—adhesion)—the—other—end—is—the fatty acid—chain—(provides—C—=—C—can—auto—oxidize)”One—molecule—=—two—chemical—functions””No need—for amine—curing agent—no need—for isocyanate—only—need—O2—+—drier”This is—the—single-component—air-drying—chemical—wisdom.
Q2: Why does waterborne epoxy ester only have salt spray resistance of 500-1000h—far lower than two-component waterborne epoxy (1500-2500h)?The crosslink density of epoxy ester (C——=——C——auto——oxidation——crosslinking——limited——in——quantity)——is——far——lower——than——that——of——two-component——epoxy’s——amine——epoxy——ring——opening——crosslinking”low——crosslink——density——=——more——water——/——O2——permeation——channels——=——low——salt——spray——resistance”.But——the——advantage——of——epoxy——ester——is”single-component——convenient——cheap””for——scenarios——not——requiring——high——corrosion——resistance——(indoor——/——C——2——C——3)——its——cost——performance——is——irreplaceable”.
Summary
Waterborne epoxy ester — one-component / autoxidative air-dry / unlimited pot life. “Affordable — convenient — light corrosion protection.” Salt spray resistance 500–1000 h — VOC < 100 — the best choice for C2–C3 corrosive environments (indoor steel structures / agricultural machinery / gates). Kexin New Materials provides the full range of waterborne epoxy ester products and formulation support: "Ready to use out of the can — making corrosion protection — so simple — that — there is — no — need — to — weigh — curing — agent."