Coated substrates and methods of preparing the same

A method for improving edge coverage of a powder coating composition on a coil metal substrate comprising:

• contacting at least a portion of the metal substrate with a first material that is:
• (i) a catalyst selected from at least one of a phosphonium compound, a quaternary ammonium halide compound, an amine compound, an imidazole compound, a sulfonium compound, and a compound comprising a transition metal and/or post-transition metal, that catalyzes cure of the powder coating composition, (ii) a component reactive with a film-forming resin and/or a crosslinker of the powder coating composition, the component selected from at least one of:
• an oxazoline-functional crosslinker;
• a polycarbodiimide functional crosslinker;
• an epoxy-functional crosslinker;
• a reactive diluent;
• and a monomer;
• and/or (iii) a rheology modifier comprising at least one of, colloidal silica, alumina, chemically modified alumina, and a rubber latex;
• rolling the metal substrate into a coil;
• unrolling the coil;
• directly contacting at least a portion of the first material on the metal substrate with the powder coating composition, wherein the powder coating composition comprises a film forming resin and a crosslinker that is reactive with the film forming resin, wherein the film forming resin comprises carboxylic acid or epoxide functional groups and the crosslinker comprises a phenolic resin, an epoxy resin, triglycidyl isocyanurate, a beta-hydroxy (alkyl) amide, a polyacid, an anhydride, an organometallic acid-functional material, a carbodiimide, and/or an oxazoline;
• and
• liquidizing the powder coating composition to form a coating layer of the powder coating composition on the metal substrate, wherein a ratio of dry film thickness of the coating layer formed from the powder coating composition at an edge of the substrate and at 10 mm away from the edge into the center is from 1:3 to 1:15.