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

1 . 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.

2 . The curable film-forming composition of claim 1 , wherein the film-forming component (b) comprises the secondary-hydroxyl functional (meth)acrylic polyol (i), and wherein the secondary-hydroxyl functional (meth)acrylic polyol (i) comprises a reaction product of a (meth)acrylic polymer having pendant epoxy functional groups and a carboxylic acid comprising at least one of isostearic acid, benzoic acid, 2-ethylhexanoic acid, isononanoic acid, pivalic acid, and 12-hydroxystearic acid.

3 . The curable film-forming composition of claim 1 , wherein the reactive diluent is present in the curable film-forming composition in an amount of at least 5 percent by weight, and at most 50 percent by weight, based on the total weight of polyol solids in the curable film-forming composition.

4 . The curable film-forming composition of claim 1 , wherein the curable film-forming composition comprises multiple, separate packages, wherein a first package comprises the polyisocyanate curing agent (a); and wherein a second package comprises:

(I) the reactive constituent (ii); and wherein the reactive diluent is present in the second package or in a third package; or

(II) the secondary-hydroxyl functional (meth)acrylic polyol (i);

and wherein the packages are separate from one another until immediately prior to application of the curable film-forming composition to a substrate.

5 . The curable film-forming composition of claim 1 , wherein the curable film-forming composition has a volatile organic compound (VOC) content less than 3.5 lb/gallon.

6 . 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) at least one of:

(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 nut shell liquid (CNSL)-based diol; an alkoxylated diol comprising a secondary hydroxyl group wherein the dial contains 2 to 6 carbon atoms prior to alkoxylation; an alkoxylated trial comprising a secondary hydroxyl group, wherein the trial 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.

7 . The curable film-forming composition of claim 6 , wherein the wherein the secondary-hydroxyl functional (meth)acrylic polyol (i) comprises a reaction product of a (meth)acrylic polymer having pendant epoxy functional groups and a carboxylic acid comprising at least one of isostearic acid, benzoic acid, 2-ethylhexanoic acid, isononanoic acid, pivalic acid, and 12-hydroxystearic acid.

8 . The curable film-forming composition of claim 6 , wherein the film-forming component (b) comprises the polymeric polyol (1).

9 . The curable film-forming composition of claim 6 , wherein the film-forming component (b) comprises the organic medium (2).

10 . The curable film-forming composition of claim 9 , wherein the reactive diluent is present in the curable film-forming composition in an amount of at least 5 percent by weight, and at most 50 percent by weight, based on the total weight of polyol solids in the curable film-forming composition.

11 . The curable film-forming composition of claim 6 , wherein the curable film-forming composition comprises multiple, separate packages, wherein a first package comprises the polyisocyanate curing agent (a); and wherein a second package comprises the film-forming component (b); and wherein the packages are separate from one another until immediately prior to application of the curable film-forming composition to a substrate.

12 . The curable film-forming composition of claim 6 , wherein the curable film-forming composition has a volatile organic compound (VOC) content less than 3.5 lb/gallon.

13 . A coating kit comprising the curable film-forming composition of claim 1 prepared as a first package and a second package, wherein the first package comprises the polyisocyanate curing agent (a) having isocyanate functional groups, and the second package comprises the film-forming component (b), and wherein the packages are separate from one another until immediately prior to application to a substrate.

14 . The coating kit of claim 13 , wherein the secondary-hydroxyl functional (meth)acrylic polyol (i) is present and comprises a reaction product of a (meth)acrylic polymer having pendant epoxy functional groups and a carboxylic acid comprising at least one of isostearic acid, benzoic acid, 2-ethylhexanoic acid, isononanoic acid, pivalic acid, and 12-hydroxystearic acid.

15 . The coating kit of claim 13 , wherein the coating kit has a volatile organic compound (VOC) content less than 3.5 lb/gallon.