Low temperature cure coating composition and method therefore

A method for a lowering the cure temperature of a coil coating composition comprising

• A) applying to a metal coil substrate a low temperature curing coating composition consisting essentially of:
• i) a film forming component consisting essentially of a non-carbamate functional polymeric component selected from the group consisting of polyester, silicone modified polyester, polyurethane, acrylic, epoxy, polyamide, phenolic and polysilane polymers and mixtures thereof;
• ii) a crosslinking component to crosslink the component (i), selected from the group consisting of melamine, unblocked polyisocyanate and blocked polylsocyanate crosslinking components;
• iii) a catalyst selected from the group consisting of (a) Lewis acids selected from the group consisting of aluminum nitrate, iron nitrate, zinc nitrate, zirconium perchlorate, barium nitrate, aluminum sulfate, and aluminum perchchorate and mixtures thereof, and (b) periluoroacetic acid, methane sulfonic acid catalysts and mixtures thereof, and mixtures of (a) and (b), and
• iv) additives selected from the group consisting of solvents, flow control agents, pigments, flexibilizing resins, surfactants, waxes, wetting agents, plasticizers, anti-oxidants, UV light absorbers, and mixtures thereof,
• B) subjecting the coated substrate to cure temperature between 300° F. (148.9° C.) and 450° F.(232.2° C.), for a time between 5 and 60 seconds, to cure the coating, whereby a cure temperature is reduced to a range of a high temperature of 525° F. and a low temperature of 425° F. to a range of a high temperature of 450° F. and a low temperature of 300° F., at equivalent times to achieve equivalent curing.