US 12,246,345 B2
Method of forming a coating on a substrate
Jeffery W. Johnson, Rochester, MI (US); Delson J. Trindade, Wilmington, DE (US); Yongqing Huang, Hockessin, DE (US); and Sedef Piril Ertem, Minneapolis, MN (US)
Assigned to AXALTA COATING SYSTEMS IP CO., LLC, Wilmington, DE (US)
Filed by AXALTA COATING SYSTEMS IP CO., LLC, Wilmington, DE (US)
Filed on Jul. 31, 2018, as Appl. No. 16/050,622.
Prior Publication US 2020/0038907 A1, Feb. 6, 2020
Int. Cl. B05D 7/00 (2006.01); B05D 1/00 (2006.01); B05D 7/14 (2006.01); B32B 27/30 (2006.01); B32B 27/36 (2006.01); C09D 175/06 (2006.01); C08L 61/28 (2006.01); C09D 5/36 (2006.01)
CPC B05D 7/5723 (2013.01) [B05D 1/007 (2013.01); B05D 7/14 (2013.01); B05D 7/532 (2013.01); B05D 7/577 (2013.01); B32B 27/30 (2013.01); B32B 27/36 (2013.01); C09D 175/06 (2013.01); B05D 2502/005 (2013.01); C08L 61/28 (2013.01); C09D 5/36 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A three coat two bake method of forming a multilayer coating on a substrate which exhibits reduced strike-in and mottling, said method comprising the steps of:
A. providing the substrate comprising a solvent-borne primer disposed thereon and subsequently baking the primer to cure;
B. applying a solvent-borne basecoat composition directly on the cured primer, wherein the basecoat composition comprises a film forming resin, a pigment, and about 12.5% to 50% by weight on binder of a cyclic lactone modified branched acrylic polymer having a hydroxyl monomer content of about 1% to about 65% by weight, all or part of which has been reacted with a cyclic lactone, and having a weight average molecular weight (Mw) of about 10,000 to about 150,000 g/mol.;
C. applying a solvent-borne clearcoat composition directly on the basecoat composition in a wet on wet process, and subsequently
D. simultaneously curing the basecoat composition and the clearcoat composition by baking to form a basecoat and a clearcoat, respectively, and to form the multilayer coating on the substrate;
wherein the multilayer coating exhibits mottling of less than about 4 measured at 15 degrees from specular reflection,
wherein the primer is free of the cyclic lactone modified branched acrylic polymer;
wherein the primer, the basecoat composition, and the clearcoat composition are each free of a cyclic lactone modified linear acrylic polymer; and
wherein the basecoat composition is free of a branched polyester.