One component, low temperature cure coating formed via a double layer curing mechanism

A low temperature cure composite coating, comprising:

• a substrate;
• a first layer comprising a first solventborne low temperature cure coating composition comprising
• a first hydroxy-functional resin,
• a first low temperature crosslinking agent, which is an aminoplast resin, and
• a first catalyst, which is a metal catalyst, and
• a first organic solvent;
• and
• a second layer comprising a solventborne low temperature cure coating composition comprising
• a second hydroxy-functional resin,
• a second low temperature crosslinking agent, which is blocked isocyanate resin,
• a second catalyst, which is an unblocked acid catalyst having a pKa from 0.25 to 1.0, and
• a second organic solvent,
• wherein the first and second layer are adjacent to each other,
• wherein the first catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the first low temperature crosslinking agent,
• wherein the second catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the first low temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low temperature crosslinking agent, and
• wherein the first and second low temperature cure coating compositions cure within 20 minutes at a temperature from 100-120° C.