UV-cured coating for roofing materials

Abstract

A building material for roofing and the like has a UV curable top coating with a resin component and a photoinitiator component. The top coating may include pigments, such as those which increase reflectivity of the coating. The speed with which the coating can be cured permits use in a roofing material assembly line without slowing the feed rate and eliminates energy intensive drying procedures.

1 . A building material, comprising
 a substrate having a bottom surface and a top surface, the bottom surface being applied proximate to a building when said substrate is used; and   a top coating applied to said top surface, said top coating having a resin component and a photoinitiator component, said photoinitiator component inducing polymerization of said resin component when a mixture of said resin component and said photoinitiator component is exposed to UV radiation to thereby cure said top coating.   
     
     
         2 . The building material of  claim 1 , further including a pigment in said top coating. 
     
     
         3 . The building material of  claim 2 , wherein said substrate is a modified asphalt roofing material. 
     
     
         4 . The building material of  claim 3 , wherein said modified asphalt roofing material includes a granular coating on said top surface, said top coating applied over said granular coating. 
     
     
         5 . A top coating for a building material, comprising a resin component and a photoinitiator component, said photoinitiator component inducing polymerization of said resin component when a mixture of said resin component and said photoinitiator component is exposed to UV radiation to thereby cure said top coating. 
     
     
         6 . The top coating of  claim 5 , wherein said resin component includes an oligomer and a monomer. 
     
     
         7 . The top coating of  claim 6 , wherein said oligomer is polyester acrylate and said monomer is neopentylglycol diacrylate. 
     
     
         8 . The top coating of  claim 7 , wherein said resin component further includes dipropyleneglycol diacrylate and pentaerythritol triacrylate. 
     
     
         9 . The top coating of  claim 8 , wherein the following constituent compounds are present in the following approximate weight percentages: polyester acrylate 10.00% to 40.00%, propoxylated neopentylglycol diacrylate 6.00% to 25.00%, dipropyleneglycol diacrylate 2.00% to 15.00%, pentaerythritol triacrylate 0.50% to 7.00%. 
     
     
         10 . The top coating of  claim 6 , further comprising a pigment component. 
     
     
         11 . The top coating of  claim 10 , wherein said pigment component includes CaCO 3  and TiO 2 . 
     
     
         12 . The top coating of  claim 11 , wherein said pigment component further includes at least one dispersal aid. 
     
     
         13 . The top coating of  claim 12 , further comprising a dispersal aid for each of said CaCO 3  and TiO 2  pigments. 
     
     
         14 . The top coating of  claim 13 , further comprising a defoamer. 
     
     
         15 . The top coating of  claim 14 , wherein the following constituent components are present in the following approximate weight percentages: CaCO 3  5.00% to 40.00%, TiO 2  5.00% to 40.00%, dispersal aids 0.30% to 7.00%, defoamer 0.10%-1.50%. 
     
     
         16 . The top coating of  claim 15 , wherein said photoinitiator component includes a plurality of photoinitiators with a combined total weight percentage of 0.60% to 11.00%. 
     
     
         17 . The top coating of  claim 9 , wherein the following constituent compounds are present in the following approximate weight percentages: polyester acrylate 30.00%, propoxylated neopentylglycol diacrylate 17.5%, dipropyleneglycol diacrylate 7.7%, pentaerythritol triacrylate 3.0%, CaCO 3  23.5%, TiO 2  11.0%, dispersal aids 2.8%, defoamer 0.5%, said plurality of photoinitiators having a combined total weight percentage of 4.0%. 
     
     
         18 . A method for making a roofing material, comprising the steps of:
 (a) providing an asphalt-based substantially planar substrate with top and bottom surfaces;   (b) preparing a flowable UV-curable coating;   (c) applying the UV-curable coating to the top surface of the substrate; and   (d) curing the coating with UV radiation to solidify the coating.   
     
     
         19 . The method of  claim 18 , wherein said step of preparing includes the steps of:
 (f) mixing at least one resin with at least one pigment to form an intermediate pigment mixture;   (g) mixing at least one photoinitiator with at least one other resin to form an intermediate photoinitiator solution;   (h) mixing the intermediate pigment mix and the intermediate photoinitiator mix.   
     
     
         20 . The method of  claim 19 , wherein said step (f) of mixing includes mixing the following constituent compounds in the following approximate weight percents: polyester acrylate 10.00% to 40.00%, propoxylated neopentylglycol diacrylate 6.00% to 25.00%, CaCO 3  5.00% to 45.00%, Titanium Kronos 2160 5.00% to 40.00%, Titanium Ukraine 2160 5.00% to 40.00%, Disperbyk 168 0.30% to 5.50%, Disperbyk 111 0.02% to 1.50%, BYK 1790 0.10% to 1.50%, and said step (g) includes mixing the following constituent compounds in the following weight percents: dipropyleneglycol diacrylate 2.00% to 15.00%, pentaerythritol triacrylate 0.50% to 7.00%, Omnirad 481 0.50% to 5.50% and Omnirad TPO 0.10% to 5.50%. 
     
     
         21 . The method of  claim 20 , wherein said step of curing is conduced under a UV light emitting greater than or equal to about 300 watts per inch.