High-solids curable film-forming compositions and methods of improving appearance of coatings containing effect pigments

A curable film-forming composition comprising:

• (a) a polyisocyanate curing agent having isocyanate functional groups;
• and
• (b) a film-forming component comprising
• (i) a secondary-hydroxyl functional (meth)acrylic polyol having pendant ester functional groups and having a weight average molecular weight of 4000 to 8000 as determined by gel permeation chromatography using a polystyrene standard, wherein the secondary hydroxyl functional (meth)acrylic polyol contains residues of an epoxy functional ethylenically unsaturated monomer from which the ester functional groups are pendant, wherein the residues are formed by reaction of epoxy functional groups with a carboxylic acid having from 5 to 20 carbon atoms, and wherein the residues are present in the secondary hydroxyl functional (meth)acrylic polyol in an amount of 20 to 35 percent by weight, based on the total weight of the secondary hydroxyl functional (meth)acrylic polyol;
• and
• (ii) a reactive constituent comprising:
• (1) a polymeric polyol comprising a polyester polyol and/or an addition polymer that is different from the secondary-hydroxyl functional (meth)acrylic polyol (i);
• and
• (2) an organic medium comprising a reactive diluent, wherein the reactive diluent comprises at least one of castor oil;
• a dimerized fatty acid diol;
• a hydroxyl functional branched polyolefin oil;
• a cashew nutshell liquid (CNSL)-based diol;
• an alkoxylated diol comprising a secondary hydroxyl group wherein the diol contains 2 to 6 carbon atoms prior to alkoxylation;
• an alkoxylated triol comprising a secondary hydroxyl group, wherein the triol contains 2 to 6 carbon atoms prior to alkoxylation, and an alkoxylated tetrol comprising a secondary hydroxyl group, wherein the tetrol contains 2 to 6 carbon atoms prior to alkoxylation;
• wherein the polymeric polyol (1) is different from and is not prepared in the reactive diluent, and
• wherein the curable film-forming composition has a total resin solids content of at least 55 percent by weight, and at most 80 percent by weight, based on the total weight of the curable film-forming composition.