Advanced Toughening Technology for Epoxy coatings

 
Part I. Background Epoxy coatings are commonly used as primers and mid-coats for corrosion protection in marine, military, infrastructure, and oil and gas sectors. Volatile organic compound regulations and asset owners' demand for higher film thickness per coat have driven demand for high-solids (HS) epoxy formulations (1). The solvent reduction requirements have forced formulators to use lower molecular weight (MW) epoxy resins to maintain their formulations' viscosity at manageable levels. HS epoxy coatings are typically more brittle than conventional low solids formulations which have lower crosslink densities due to the use of higher MW epoxy resins and the residual solvent that helps to plasticize the coatings. Hence, HS epoxy systems are more susceptible to damage by impact, abrasion, and gouging in the demanding environments in which they serve. For example, a typical commercially available HS epoxy coating will often fail a ¼-inch mandrel bend and will only provide about 20 lbs of direct, rapid impact resistance at 25 °C; at freezing or subzero temperatures most HS epoxy coatings become even more brittle.