Two-component coating composition and method of preparation

A process for preparing a coating composition comprising:

• (A) forming an aqueous-based mixture by combining:
• (i) a first polymer comprising, as polymerized monomer units:
• (a) 16 to 20 percent, based on weight of the first polymer, of monoethylenically unsaturated monomer containing a carboxylic acid functional group;
• (b) 3 to 15 percent, based on weight of the first polymer, of a (meth)acrylic monomer containing hydroxy functional groups;
• (c) 20 to 50 percent, based on weight of the first polymer, of vinylaromatic monomer;
• and
• (d) 25 to 45 percent, based on weight of the first polymer, of one or more (C1-C8)alkyl (meth)acrylate ester monomers;
• and
• (ii) a polyfunctional crosslinker agent comprising isocyanate pendant functional groups;
• wherein, the first polymer has a number average molecular weight from 200,000 to 1,000,000;
• and the polyfunctional crosslinker agent is used in an amount sufficient to provide from 0.2 to 5 equivalents of pendant functional group per equivalent of corresponding pendant reactive functional group in the first polymer;
• and
• (B) applying the aqueous-based mixture to a substrate.

A process for preparing a coated substrate comprising:

• (A) forming an aqueous-based mixture by combining:
• (i) a first polymer comprising, as polymerized monomer units:
• (a) 16 to 25 percent, based on weight of the first polymer, of a monoethylenically unsaturated monomer containing an acidic functional group selected from one or more of carboxylic, sulfonic and phosphonic groups;
• (b) 1 up to 60 percent, based on weight of the first polymer, of a (meth)acrylic monomer containing one or more pendant reactive functional groups selected from hydroxy, thiol, and amino groups;
• (c) 10 to 70 percent, based on weight of the first polymer, of one or more vinylaromatic monomers;
• (d) 15 to 90 percent, based on weight of the first polymer, of one or more (C1-C20)alkyl(meth)acrylate ester monomers;
• and
• (e) zero up to 10 percent, based on weight of the first polymer, of one or more other copolymerizable monomers;
• and
• (ii) a polyfunctional crosslinker agent comprising pendant functional groups selected from one or more of isocyanate, carbodiimide, aziridinyl and epoxy groups;
• wherein, the first polymer has a number average molecular weight from greater than 50,000 up to 2,000,000;
• and the polyfunctional crosslinker agent is used in an amount sufficient to provide from 0.2 to 5 equivalents of pendant functional group per equivalent of corresponding pendant reactive functional group in the first polymer;
• and
• (B) applying the aqueous-based mixture to a substrate.