Corrosion Control Advantages of Polyamide-Epoxy Coatings

Chemical and physical properties of polyamide resins are described. Resistance of General Mills' polyamide resins to various acidic and alkaline corrosives in both static and dynamic tests are compared to those achieved with commercial inhibitors. Results of tests in a semi-tropical ocean environment of 17 primer types consisting of various combinations and percentages of polyamide-epoxy vehicle with zinc, chrome and lead pigments; alkyds, phenolics, vinyls, poly-vinylchlorides and a linseed oil vehicle are given. These tests of angle irons and flat panels up to 24 months showed polyamide-epoxy systems (with or without corrosion inhibiting pigments) to be better than others, even when brushed onto wet, rusty surfaces. Wetting ability, adhesion and flexibility of the polyamide-epoxy systems as registered in several tests are reported. Also given are rate of transmission of water and water vapor. Data are provided on formulations and application techniques. These include sand-filled coating, solventless finishes (with tests versus several corrosives and solvents). Also given are descriptions of applications as pipe coatings, marine submersion service, for aircraft and concrete. 19 references. 6.8, 5.4.5