Multi-component coatings that include polyurea coating layers

A method of forming a polyurea coating on a substrate comprising:

• (a) selecting an isocyanate-functional composition and an amine-functional composition such that the ratio of equivalents of isocyanate groups to equivalents of amine groups is greater than 1 while the volume mixing ratio of the isocyanate-functional component to the amine-functional component is capable of being applied to the substrate at 1:1;
• wherein at least 1 percent by weight of the isocyanate-functional component comprises at least one polyisocyanate monomer and wherein the isocyanate-functional component further comprises the reaction product of a polyisocyanate and two or more polyols, and wherein the amine component comprises an aspartic ester-based amine-functional resin;
• (b) mixing the isocyanate-functional composition and the amine-functional composition in a volume ratio to produce a reaction mixture;
• and
• (c) applying the reaction mixture to a substrate to form a polyurea coating on the substrate.

A method of forming a coated article, comprising:

• providing a substrate;
• and
• depositing a multilayer composite coating on at least a portion of the substrate to form the coated article, the multilayer composite coating comprising a first polyurea layer deposited from a first composition, and a second polyurea layer deposited from a second composition, applied over at least a portion of the first polyurea layer, at least one of the first composition and the second composition being formed from a reaction mixture comprising:
• an isocyanate component;
• and
• an amine component
• wherein the ratio of equivalents of isocyanate groups to equivalents of amine groups in the reaction mixture is greater than 1 while the volume mixing ratio of the isocyanate-functional component to the amine-functional component is capable of being applied to a substrate at 1:1;
• and wherein at least 1 percent by weight of the isocyanate-functional component comprises at least one polyisocyanate monomer and wherein the isocyanate-functional component further comprises the reaction product of a polyisocyanate and two or more polyols, and wherein the amine component comprises an aspartic ester-based amine-functional resin.