US 12,305,061 B2
Apparatus and methods for alternative coatings applicable to metal
John Cunningham, Tracy, CA (US); Kenneth Metzger, Cincinnati, OH (US); and Timmy Sath Ka, Stockton, CA (US)
Assigned to G3 Enterprises, Inc., Modesto, CA (US)
Filed by G3 Enterprises, Inc., Modesto, CA (US)
Filed on Mar. 23, 2023, as Appl. No. 18/188,869.
Application 18/188,869 is a division of application No. 15/266,893, filed on Sep. 15, 2016, granted, now 11,634,606.
Claims priority of provisional application 62/218,870, filed on Sep. 15, 2015.
Prior Publication US 2023/0250309 A1, Aug. 10, 2023
Int. Cl. B05D 1/28 (2006.01); B05D 1/40 (2006.01); B32B 15/085 (2006.01); C09D 123/08 (2006.01)
CPC C09D 123/0869 (2013.01) [B32B 15/085 (2013.01); B05D 1/28 (2013.01); B05D 1/40 (2013.01); B05D 2202/25 (2013.01)] 17 Claims
 
1. A method of forming a screw cap closure, the method comprising:
coating an exterior side of a sheet metal substrate with a first layer comprising a first ethylene acrylic acid copolymer;
coating the first layer with a second layer comprising a second ethylene acrylic acid copolymer;
coating the second layer with an over-varnish layer comprising a third ethylene acrylic acid copolymer;
coating an interior side of the sheet metal substrate with an interior lacquer layer comprising a fourth ethylene acrylic acid copolymer;
curing the first layer, second layer, over-varnish layer, and interior lacquer layer by applying heat to form a coating on the sheet metal substrate; and
elongating the sheet metal substrate and the coating in a deep draw process to form a screw cap closure;
wherein each of the first layer, the second layer, the over-varnish layer, and the interior lacquer layer comprises a single type of polymer; and
wherein an acrylic acid content in the single type of polymer is from 19.5 to 21.5 weight percent based upon a total weight of the single type of polymer.