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US 12,678,824 B2Granted
Multi-layer coatings and methods of preparing the same
AssigneePPG Industries Ohio, Inc.
InventorsWei Wang, David Robert Fenn, Leigh Ann Humbert
Life of this patent
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Abstract
A multi-layer coating system includes: a first basecoat layer formed from a first coating composition including a free polyisocyanate having a weight average molecular weight of less than 600 g/mol and hydroxyl functional polymeric core-shell particles, where an amount of free polyisocyanate having a weight average molecular weight of less than 600 g/mol is 3.5 weight % or greater; a second basecoat layer formed from a second coating composition including carboxylic acid functional polymeric core-shell particles; and a topcoat layer formed from a coating composition including a free polyisocyanate and a film-forming resin reactive with the free polyisocyanate.
Claims20
A multi-layer coating system comprising:
- 1) a first basecoat layer formed from a first coating composition comprising:
- a) at least two different free polyisocyanates comprising:
- i) a free aliphatic polyisocyanate having a weight average molecular weight of less than 600 g/mol, present in an amount of 3.5 to 8 weight %, based on the total resin solids of the first coating composition;
- and
- ii) a uretdione dimer different from the free aliphatic polyisocyanate i), present in an amount greater than 9.5 weight %, based on the total resin solids of all the free polyisocyanate in the first coating composition;
- b) at least two different types of polymeric core-shell particles comprising:
- i) hydroxyl functional polymeric core-shell particles, wherein a polymeric core and a polymeric shell of the hydroxyl functional core-shell particles each independently comprise an addition polymer derived from ethylenically unsaturated monomers, wherein the hydroxyl functional polymeric core-shell particles are present in the first coating composition in an amount of 20 to 60 percent by weight, based on the total weight of resin solids of the first coating composition;
- and
- ii) carboxylic acid functional polymeric core-shell particles, wherein a polymeric core of the carboxylic acid functional core-shell particles comprises an addition polymer derived from ethylenically unsaturated monomers including a monomer having at least two ethylenically unsaturated groups and a polymeric shell of the carboxylic acid functional core-shell particles comprises urethane linkages and carboxylic acid functional groups, wherein the carboxylic acid functional polymeric core-shell particles are present in the first coating composition in an amount of 0.1 to 20 percent by weight, based on the total weight of resin solids of the first coating composition;
- and
- c) a crosslinking agent different from the free polyisocyanates a);
- 2) a second basecoat layer positioned over at least a portion of the first basecoat layer, the second basecoat layer formed from a second coating composition comprising:
- a) second carboxylic acid functional polymeric core-shell particles, wherein a polymeric core of the second carboxylic acid functional core-shell particles comprises an addition polymer derived from ethylenically unsaturated monomers and a polymeric shell of the second carboxylic acid functional core-shell particles comprises urethane linkages and carboxylic acid functional groups, wherein the second carboxylic acid functional polymeric core-shell particles are present in the second coating composition in an amount of greater than 20 and up to 60 percent by weight, based on the total weight of resin solids of the second coating composition;
- and
- b) a second crosslinking agent;
- and
- 3) a topcoat layer positioned over at least a portion of the second basecoat layer, the topcoat layer formed from a topcoat coating composition comprising a second free polyisocyanate and a film-forming resin reactive with the second free polyisocyanate.
14 more elements
A process of coating a substrate with a multi-layer coating comprising:
- (1) depositing a first coating composition onto at least a portion of the substrate, wherein the first coating composition comprises:
- a) at least two different free polyisocyanates comprising:
- i) a free aliphatic polyisocyanate having a weight average molecular weight of less than 600 g/mol, present in an amount of 3.5 to 8 weight %, based on the total resin solids of the first coating composition;
- and
- ii) a uretdione dimer different from the free aliphatic polyisocyanate i), present in an amount greater than 9.5 weight %, based on the total resin solids of all the free polyisocyanate in the first coating composition;
- b) at least two different types of polymeric core-shell particles comprising:
- i) hydroxyl functional polymeric core-shell particles, wherein a polymeric core and a polymeric shell of the hydroxyl functional core-shell particles each independently comprise an addition polymer derived from ethylenically unsaturated monomers, wherein the hydroxyl functional polymeric core-shell particles are present in the first coating composition in an amount of 20 to 60 percent by weight, based on the total weight of resin solids of the first coating composition;
- and
- ii) carboxylic acid functional polymeric core-shell particles, wherein a polymeric core of the carboxylic acid functional core-shell particles comprises an addition polymer derived from ethylenically unsaturated monomers including a monomer having at least two ethylenically unsaturated groups and a polymeric shell of the carboxylic acid functional core-shell particles comprises urethane linkages and carboxylic acid functional groups, wherein the carboxylic acid functional polymeric core-shell particles are present in the first coating composition in an amount of 0.1 to 20 percent by weight, based on the total weight of resin solids of the first coating composition;
- and
- c) a crosslinking agent different from the free polyisocyanates a);
- (2) depositing a second coating composition directly onto at least a portion of the first coating composition (A) after the first coating composition is dehydrated or (B) before the first coating composition is dehydrated, wherein the second coating composition comprises:
- a) second carboxylic acid functional polymeric core-shell particles, wherein a polymeric core of the second carboxylic acid functional core-shell particles comprises an addition polymer derived from ethylenically unsaturated monomers and a polymeric shell of the second carboxylic acid functional core-shell particles comprises urethane linkages and carboxylic acid functional groups, wherein the second carboxylic acid functional polymeric core-shell particles are present in the second coating composition in an amount of greater than 20 and up to 60 percent by weight, based on the total weight of resin solids of the second coating composition;
- and
- b) a second crosslinking agent;
- (3) dehydrating:
- (a) the second coating composition after (2) (A);
- or (b) simultaneously the first coating composition and the second coating composition after (2) (B);
- and
- (4) depositing a topcoat coating composition over at least a portion of the dehydrated second coating composition, the topcoat coating composition comprising a second free polyisocyanate and at least one film-forming resin reactive with the second free polyisocyanate.
17 more elements
Dependencies are inferred from the claim text.