Crosslinkable imide polyester coating
AssigneeValspar Sourcing, Inc.
InventorsGregory B. Hayes, Thomas J. Melnyk
Life of this patent
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Abstract
A primer/topcoat coil coating system employs crosslinkable branched hydroxyl-functional polyester-imide resins derived or derivable from a symmetric aromatic imide triol and a diacid or acid-producing derivative. The primer resin has a hydroxyl number greater than about 90 but not more than about 215, the topcoat resin has a hydroxyl number greater than about 100 but not more than about 215, and the primer and topcoat can each be hardened in 30 seconds or less to provide a coating having at least 0T flexibility with no tape off and at least 2H pencil hardness.
Claims17
A coated substrate comprising a metallic substrate coil having first and second major surfaces and a primer and topcoat coating system on at least one major surface, wherein the primer and topcoat each comprise a binder containing (a) a branched hydroxyl-functional imide polyester resin derived or derivable from (i) a symmetric heterocyclic imide triol and (ii) a diacid or acid-producing derivative thereof, and (b) a blocked polyisocyanate crosslinking agent, wherein the primer imide polyester resin has a hydroxyl number of about 90 to 150, the topcoat imide polyester resin has a hydroxyl number of about 100 to 150, wherein the primer resin hydroxyl number is less than the topcoat resin hydroxyl number, and the primer and topcoat can each be hardened in 30 seconds or less to provide a coating having at least 0T flexibility with no tape off and at least 2H pencil hardness.
Dependencies are inferred from the claim text.