Multilayer coated substrates

Abstract

A multilayer coated substrate is disclosed, comprising: (a) a cured basecoat layer formed from a curable basecoat layer comprising a color-imparting, pigment-containing basecoat composition applied directly to a cured electrodeposited primer coating without application of an intermediate primer surfacer coating, and (b) a curable unpigmented coating composition applied to the cured basecoat layer to form a clear or transparent coating layer over the cured basecoat layer. The cured electrodeposited primer coating is adhered to the substrate. The basecoat layer is deposited from a curable aqueous composition comprising: (i) a continuous phase comprising water, and (ii) a dispersed phase comprising: (A) polymeric particles containing carboxylic acid functionality; and (B) a polycarbodiimide. The polymeric particles are prepared by polymerization of a mixture of ethylenically unsaturated compounds, including a multi-ethylenically unsaturated monomer. The cured basecoat layer demonstrates a glass transition temperature less than 25° C.

What is claimed is: 
     
         1 . A multilayer coated substrate comprising:
 (a) a cured basecoat layer formed from a curable color-imparting basecoat layer comprising a color-imparting, pigment-containing basecoat composition applied directly to a cured electrodeposited primer coating without application of an intermediate primer surfacer coating, wherein the cured electrodeposited primer coating is adhered to the substrate, and   (b) a curable unpigmented coating composition applied to the cured basecoat layer to form a clear or transparent coating layer over the cured basecoat layer, wherein the basecoat layer is deposited from a curable aqueous composition comprising:
 (i) a continuous phase comprising water, and 
 (ii) a dispersed phase comprising:
 (A) polymeric particles containing carboxylic acid functionality, wherein the polymeric particles are prepared by polymerization of a mixture of ethylenically unsaturated compounds, including a multi-ethylenically unsaturated monomer; and 
 (B) a polycarbodiimide; wherein the cured basecoat layer demonstrates a glass transition temperature less than 25° C. 
 
   
     
     
         2 . The multilayer coated substrate of  claim 1  wherein the curable color-imparting basecoat layer comprises a composite coating wherein an aqueous curable color-imparting coating composition containing one or more coloring pigments, not including a color effect pigment, is deposited directly on the cured electrodeposited primer coating to form a first curable basecoat layer, and an aqueous curable color-imparting coating composition containing one or more coloring pigments, including a color effect pigment, is deposited directly on the first curable basecoat layer to form a second curable basecoat layer. 
     
     
         3 . The multilayer coated substrate of  claim 1  wherein the mixture of ethylenically unsaturated compounds includes an ethylenically unsaturated polyurethane. 
     
     
         4 . The multilayer coated substrate of  claim 3  wherein the ethylenically unsaturated polyurethane is prepared from a reaction mixture comprising an organic polyisocyanate, a polyol containing carboxylic acid functionality, and a hydroxyalkyl (meth)acrylate such that the ethylenically unsaturated polyurethane is free of NCO groups. 
     
     
         5 . The multilayer coated substrate of  claim 3  wherein the ethylenically unsaturated polyurethane has an acid value of 20 to 60 based on resin solids of the ethylenically unsaturated polyurethane. 
     
     
         6 . The multilayer coated substrate of  claim 3  wherein the ethylenically unsaturated polyurethane is present in the mixture of ethylenically unsaturated compounds in an amount of 30 to 60 percent by weight, based on the total weight of the mixture of ethylenically unsaturated compounds. 
     
     
         7 . The multilayer coated substrate of  claim 1  wherein the multi-ethylenically unsaturated monomer is present in the mixture of ethylenically unsaturated compounds in an amount of 2 to 30 percent by weight based on the total weight of the ethylenically unsaturated compounds. 
     
     
         8 . The multilayer coated substrate of  claim 1  wherein the ethylenically unsaturated compounds comprise 4 to 30 percent by weight of an alkyl ester of (meth)acrylic acid having at least 6 carbon atoms in the alkyl group, based on the total weight of the ethylenically unsaturated compounds. 
     
     
         9 . The multilayer coated substrate of  claim 1  wherein the equivalent ratio of polycarbodiimide to carboxylic acid is from 0.5 to 1.5:1. 
     
     
         10 . The multilayer coated substrate of  claim 1  wherein the curable unpigmented coating composition comprises an active hydrogen-containing polymer and a polyisocyanate curing agent. 
     
     
         11 . The multilayer coated substrate of  claim 1  wherein the substrate comprises a metal. 
     
     
         12 . The multilayer coated substrate of  claim 11  wherein the substrate is in the form of an automotive body component. 
     
     
         13 . The multilayer coated substrate of  claim 12  wherein the automotive body component comprises a frame, hood, door, fender, bumper, or trim.