Multi-layer coatings and methods of preparing the same

A process of coating a substrate with a multi-layer coating comprising:

• forming a first basecoat layer over at least a portion of a substrate by depositing a first coating composition onto at least a portion of the substrate, wherein the first basecoat layer is formed from a first coating composition comprising a free polyisocyanate and hydroxyl functional polymeric core-shell particles, wherein a polymeric core and a polymeric shell of the hydroxyl functional core-shell particles each independently comprise an addition polymer derived from ethylenically unsaturated monomers;
• forming a second basecoat layer over at least a portion of the first basecoat layer by depositing a second coating composition directly onto at least a portion of (1) the first basecoat layer after the first coating composition is dehydrated or (2) the first coating composition before the first coating composition is dehydrated, wherein the second basecoat layer is formed from a second coating composition comprising carboxylic acid functional polymeric core-shell particles in which a polymeric core of the carboxylic acid functional core-shell particles comprises an addition polymer derived from ethylenically unsaturated monomers and a polymeric shell of the carboxylic acid functional core-shell particles comprises urethane linkages and carboxylic acid functional groups;
• and
• forming a topcoat layer over at least a portion of the second basecoat layer, the topcoat layer formed from a coating composition comprising at least one free polyisocyanate having a weight average molecular weight of less than 600 g/mol and at least one film-forming resin reactive with the free polyisocyanate, wherein an amount of free polyisocyanate having a weight average molecular weight of less than 600 g/mol is greater than 5 weight %, based on the total resin solids of the coating composition that forms the topcoat layer,
• wherein the first basecoat composition and second basecoat composition are dehydrated at a temperature within a range of from ambient temperature to 90° C. for two minutes or less;
• and wherein the free polyisocyanate in the coating composition that forms the topcoat layer comprises greater than 30 weight % of a uretdione dimer, based on the total resin solids weight of all the free polyisocyanate in the coating composition that forms the topcoat layer.