Anti-corrosive primer coating material having electrostatic photographic properties based on epoxy resins

摘要

Anti-corrosive primer coating materials having electrostatic photographic properties comprise (1) one or more epoxy resins and (2) one or more isocyanates or isocyanate resins having at least two isocyanate groups, as curing agent for the epoxy resin(s), and (3) a photoconductor. Photoconductors specified are zinc oxide and selenium compounds. The compositions may also contain sensitizers and solvents. Conventional photosensitive coating materials used in comparative examples all comprise organic solvents, special grade ZnO and (a) a vinyl-chloride-vinyl acetate copolymer; (b) a silicone resin and a vinyl acetate copolymer; and (c) an epoxy resin and an amine adduct secondary curing agent.ALSO:Shot-blasted steel panels are coated, by spraying with a primer coating material having electrostatic photographic properties comprising an epoxy resin, an isocyanate or isocyanate resin having at least 2-NCO groups, as curing agent for the epoxy resin organic solvents and a photoconductor. Optional ingredients of the compositions are sensitizers. The coatings are cured in a hot air drying furnace and may be recoated with, e.g. a coal tar epoxy paint. For comparative purposes compositions comprising organic solvents, special grade ZnO and (a) a vinyl chloride-vinyl acetate copolymer, (b) a silicone resin and a vinyl acetate copolymer, and (c) an epoxy resin and an amine adduct secondary curing agent are used.