Roofing products with zones of algae-resistant granules and method of manufacture

Abstract

The present disclosure relates generally to roofing products, for example, suitable for use covering and protecting the roofs of structures. The present disclosure relates more particularly to a roofing product including an upper section and an exposed section. The roofing product includes a substrate having a top surface and a bottom surface, and a plurality of zones of roofing granules disposed on the top surface of the substrate. The plurality of zones includes first, second and third zones within the exposed section. The first zone includes a first collection of algae-resistant roofing granules and has a first algae-resistance intensity. The second zone includes a second collection of algae-resistant roofing granules and has a second algae-resistance intensity. The third zone has a third algae-resistance intensity that is different from the first algae-resistance intensity.

1 .- 20 . (canceled) 
     
     
         21 . A roofing product including an upper section and an exposed section, the roofing product comprising:
 a substrate including a top surface and a bottom surface; and   a plurality of zones of roofing granules disposed on the top surface of the substrate, the plurality of zones including:
 a first zone within the exposed section of the roofing product, the first zone having a first algae-resistance intensity; and 
 a second zone within the exposed section of the roofing product, the second zone having a second algae-resistance intensity; 
   wherein the first algae-resistance intensity is different from the second algae-resistance intensity.   
     
     
         22 . The roofing product according to  claim 21 , wherein the roofing product is a roofing shingle, a roofing membrane, or a roofing tile. 
     
     
         23 . The roofing product according to  claim 21 , wherein the first zone includes a first collection of algae resistant roofing granules. 
     
     
         24 . The roofing product according to  claim 21 , wherein the first zone has a first concentration of algae-resistant roofing granules, the second zone has a second concentration of algae resistant granules, and wherein the first concentration is higher than the second concentration. 
     
     
         25 . The roofing product according to  claim 21 , wherein the first zone includes a concentration of algae-resistant roofing granules in a range of 1% to 20%, and the second zone includes a concentration of algae-resistant roofing granules in a range of 0% to 15%. 
     
     
         26 . The roofing product according to  claim 21 , wherein a concentration of algae-resistant roofing granules in the first zone is at least 1% higher than a concentration of algae-resistant roofing granules in the second zone. 
     
     
         27 . The roofing product according to  claim 21 , wherein the second zone includes a concentration of algae-resistant roofing granules in a range of 0% to 20%. 
     
     
         28 . The roofing product according to  claim 21 , wherein the first zone comprises an inorganic algaecide, consisting of copper oxide, copper compounds, zinc oxide, titanium oxide, silver, copper, zinc, and mixtures thereof; or an organic algaecide, comprising of zinc pyrithione, amines and ammonium salts, quaternary ammonium chloride, ammonium compounds, chloride compounds; or a combination of inorganic and organic algaecides. 
     
     
         29 . The roofing product according to  claim 21 , wherein the first zone includes a first group of algae-resistant granules that have a first algaecide concentration that is different from an algaecide concentration of any of the granules of the second zone. 
     
     
         30 . The roofing product according to  claim 21 , wherein the roofing product comprises algae-resistant granules having algaecide concentrations in a range from 0.02% by weight to 50% by weight. 
     
     
         31 . The roofing product according to  claim 21 , wherein a first group of algae-resistant granules of the first zone have a first algaecide concentration that is higher than any class of granules in the second zone. 
     
     
         32 . The roofing product according to  claim 21 , wherein the first zone includes a first group of algae-resistant granules that have an algaecide time-release characteristic that is different from an algaecide time-release characteristic of any granules of the second zone. 
     
     
         33 . The roofing product according to  claim 21 , the second zone comprises an inorganic algaecide, consisting of copper oxide, copper compounds, zinc oxide, titanium oxide, silver, copper, zinc, and mixtures thereof or an organic algaecide, comprising of zinc pyrithione, amines and ammonium salts, quaternary ammonium chloride, ammonium compounds, chloride compounds, or a combination of inorganic and organic algaecides. 
     
     
         34 . The roofing product according to  claim 21 , wherein the first zone includes a first group of algae-resistant granules that have an algaecide release-rate characteristic that is different from an algaecide time-release characteristic of any granules of the second zone. 
     
     
         35 . The roofing product according to  claim 21 , wherein the first zone includes a first group of roofing granules having a first color that is different from a second color of a second group of roofing granules in the second zone. 
     
     
         36 . The roofing product according to  claim 35 , wherein a first group of roofing granules e and the second group of roofing granules have a color difference ΔE of at least 2. 
     
     
         37 . The roofing product according to  claim 21 , wherein the first zone includes a first group of algae-resistant granules that have a release delay that is different from a release delay of any granules of the second zone. 
     
     
         38 . The roofing product according to  claim 21 , wherein the first zone is disposed at an upper edge of the exposed section of the roofing product or at a lower edge of the exposed section of the roofing product. 
     
     
         39 . The roofing product according to  claim 38 , wherein the second zone is disposed at a lower edge of the exposed section of the roofing product or at an upper edge of the exposed section of the roofing product. 
     
     
         40 . A method of manufacturing a roofing product according to  claim 21 , the method comprising:
 providing a substrate including a top surface and a bottom surface; and   depositing a plurality of zones of roofing granules on the top surface of the substrate, the plurality of zones including:
 a first zone within the exposed section of the roofing product and comprising a first collection of algae-resistant roofing granules, the first zone having a first algae-resistance intensity; 
 a second zone within the exposed section of the roofing product and comprising a second collection of algae-resistant roofing granules, the second zone having a second algae-resistance intensity.