Hybrid coating stack

Abstract

A coating includes a functional coating, such as a solar control coating having at least one metal layer. A topcoat is formed over at least a portion of the functional coating. The topcoat includes a first topcoat layer having a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a reference wavelength of 550 nm and a first refractive index, and a second topcoat layer having a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a reference wavelength of 550 nm and a second refractive index different from the first refractive index.

1 . A coating, comprising: 
 a functional coating comprising at least one metal layer; and    a topcoat formed over at least a portion of the functional coating, the topcoat comprising: 
 a first topcoat layer having a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a wavelength of 550 nm and a first refractive index; and  
 a second topcoat layer having a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a wavelength of 550 nm and having a second refractive index different from the first refractive index.  
   
     
     
         2 . The coating of  claim 1 , wherein the metal layer includes at least one of gold, copper, silver, or mixtures, alloys, or combinations including at least one thereof.  
     
     
         3 . The coating of  claim 1 , wherein the functional coating comprises a first metal oxide layer and a second metal oxide layer, with the metal layer positioned between the metal oxide layers.  
     
     
         4 . The coating of  claim 1 , wherein the first topcoat layer has a low refractive index and the second topcoat layer has a high refractive index.  
     
     
         5 . The coating of  claim 1 , wherein the first topcoat layer has a high refractive index and the second topcoat layer has a low refractive index.  
     
     
         6 . The coating of  claim 1 , wherein the refractive index of the first topcoat layer differs from the refractive index of the second topcoat layer by a value in the range of 0.2 to 1.0.  
     
     
         7 . The coating of  claim 1 , wherein the first topcoat layer has a refractive index of 2 or less and the second topcoat layer has a refractive index greater than 2.  
     
     
         8 . The coating of  claim 1 , wherein the first topcoat layer has a refractive index of greater than 2 and the second topcoat layer has a refractive index of 2 or less.  
     
     
         9 . The coating of  claim 1 , wherein the first topcoat layer comprises at least one metal oxide selected, from oxides of aluminum, silicon, yttrium, tin, and mixtures thereof.  
     
     
         10 . The coating of  claim 1 , wherein the second topcoat layer comprises at least one metal oxide selected from oxides of titanium, zirconium, niobium, bismuth, tungsten, zinc, tin, and mixtures thereof.  
     
     
         11 . The coating of  claim 3 , wherein the first metal oxide layer comprises at least one oxide of zinc, tin, or alloys or mixtures thereof, the second metal oxide layer comprises at least one oxide of zinc, tin, or alloys or mixtures thereof, the metal layer comprises silver, one of the first topcoat layer or the second topcoat layer comprises at least one metal oxide selected from oxides of aluminum, silicon, yttrium, tin, and mixtures thereof, and the other of the first topcoat layer or second topcoat layer comprises at least one metal oxide selected from oxides of titanium, zirconium, niobium, bismuth, tungsten, zinc, tin, and mixtures thereof.  
     
     
         12 . The coating of  claim 1 , wherein the topcoat further comprises a third topcoat layer having a thickness in the range of 0.5 QWOT to 1 QWOT with respect to a reference wavelength of 550 nm and a refractive index different from the second refractive index.  
     
     
         13 . The coating of  claim 12 , wherein the third topcoat layer comprises a low refractive index material.  
     
     
         14 . The coating of  claim 12 , wherein the third topcoat layer comprises a high refractive index material.  
     
     
         15 . The coating of  claim 12 , wherein the third topcoat layer comprises silicon dioxide.  
     
     
         16 . A coating, comprising: 
 a functional coating comprising at least one infrared reflective metal layer; and    a topcoat formed over at least a portion of the functional coating, wherein the topcoat comprises: 
 a first topcoat layer having a first refractive index deposited over at least a portion of the functional coating; and  
 a second topcoat layer having a second refractive index deposited over at least a portion of the first dielectric layer, wherein the difference between the first refractive index and the second refractive index is in the range of 0.2 to 1.  
   
     
     
         17 . The coating of  claim 16 , wherein the refractive index difference is in the range of 0.2 to 0.6.  
     
     
         18 . The coating of  claim 16 , wherein the first topcoat layer has a low refractive index and the second topcoat layer has a high refractive index.  
     
     
         19 . The coating of  claim 16 , wherein the first topcoat layer has a high refractive index and the second topcoat layer has a low refractive index.  
     
     
         20 . The coating of  claim 16 , wherein the first topcoat layer comprises at least one metal oxide selected from the group consisting of oxides of aluminum, silicon, yttrium, tin, and mixtures thereof.  
     
     
         21 . The coating of  claim 16 , wherein the second topcoat layer comprises at least one metal oxide selected from the group consisting of oxides of titanium, zirconium, niobium, bismuth, tungsten, zinc, tin, and mixtures thereof.  
     
     
         22 . The coating of  claim 16 , wherein the infrared reflective metal layer comprises silver, one of the first topcoat layer or the second topcoat layer comprises at least one metal oxide selected from oxides of aluminum, silicon, yttrium, tin, and mixtures thereof, and the other of the first topcoat layer or second topcoat layer comprises at least one metal oxide selected from oxides of titanium, zirconium, niobium, bismuth, tungsten, zinc, tin, and mixtures thereof.  
     
     
         23 . The coating of  claim 16 , wherein the topcoat further comprises a third topcoat layer deposited over the second topcoat layer, the third topcoat having a third refractive index different from the second refractive index.  
     
     
         24 . A coated article, comprising: 
 a substrate; and    a coating as defined in  claim 1  deposited over at least a portion of the substrate.    
     
     
         25 . A coated article, comprising: 
 a substrate; and    a coating deposited over at least a portion of the substrate, the coating comprising: 
 a functional coating comprising a first metal oxide layer, a second metal oxide layer, and an infrared reflective metal layer positioned between the first and second metal oxide layers; and  
 a topcoat comprising a first topcoat layer and a second topcoat layer,  
 wherein the first topcoat layer has a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a reference wavelength of 550 nm and a first refractive index of (i) less than or equal to 2, or (ii) greater than 2, and  
 wherein the second topcoat layer has a thickness in the range of 0.5 QWOT to 1.5 QWOT with respect to a wavelength of 550 nm and a second refractive index of (i) greater than 2 when the first refractive index is less than or equal to 2, and (ii) less than or equal to 2 when the first refractive index is greater than 2.  
   
     
     
         26 . The coated article of  claim 25 , wherein the first metal oxide layer comprises at least one oxide of zinc, tin or alloys or mixtures thereof and having a thickness in the range of 0.25 QWOT to 1 QWOT, the metal layer comprises silver, and the second metal oxide layer comprises at least one oxide of zinc, tin or alloys or mixtures thereof and having a thickness in the range of 0.1 QWOT to 0.9 QWOT.  
     
     
         27 . The coated article of  claim 25 , further comprising a second substrate laminated to the first substrate.  
     
     
         28 . The coated article of  claim 25 , wherein one of the first topcoat layer or the second topcoat layer comprises at least one metal oxide selected from oxides of aluminum, silicon, yttrium, tin, and mixtures thereof, and the other of the first topcoat layer or second topcoat layer comprises at least one metal oxide selected from oxides of titanium, zirconium, niobium, bismuth, tungsten, zinc, tin, and mixtures thereof.  
     
     
         29 . The coated article of  claim 25 , wherein the topcoat further comprises a third topcoat layer having a thickness in the range of 0.5 QWOT to 1 QWOT and a third refractive index of (i) less than or equal to 2 when the second refractive index is greater than 2, and (ii) greater than 2 when the second refractive index is less than or equal to 2.