Search

US-12624550-B2 - Coated roofing granules, roofing materials made therefrom and methods of preparing coated roofing granules

US12624550B2US 12624550 B2US12624550 B2US 12624550B2US-12624550-B2

Abstract

This invention relates to coated roofing granules, roofing materials made therefrom, and methods of preparing such coated roofing granules. By coating roofing granules with an aqueous coating that includes water, a silicon-containing oligomer or polymer, and an acrylic resin, coated roofing granules can be prepared that exhibit reduced staining as compared to traditional roofing granules that are treated with petroleum oil.

Inventors

  • David D. Kragten
  • Daniel E. Rardon

Assignees

  • SPECIALTY GRANULES INVESTMENTS LLC

Dates

Publication Date
20260512
Application Date
20240801

Claims (20)

  1. 1 . A coated roofing granule comprising: (a) a roofing granule; and (b) a post-treatment coating on the roofing granule, the post-treatment coating comprising: (i) at least one silicon-containing oligomer or silicon-containing polymer that is present in an amount of 0.01 to 5 pounds per ton of roofing granule; and (ii) an acrylic resin that is present in an amount of 0.1 to 5 pounds per ton of roofing granules, wherein the coating is substantially free of water.
  2. 2 . The coated roofing granule according to claim 1 , wherein the coated roofing granule exhibits a total solar reflectance that is 90 percent to 100 percent of the total solar reflectance of the roofing granule without the post-treatment coating.
  3. 3 . The coated roofing granule according to claim 2 , wherein the coated roofing granule exhibits a total solar reflectance that is equal to the total solar reflectance of the roofing granule without the post-treatment coating.
  4. 4 . The coated roofing granule according to claim 1 , wherein the coated roofing granule exhibits a granule color having an L value, as measured by a Hunter L, a, and b color scale, that is 90 percent to 100 percent of an L value of the roofing granule without the post-treatment coating.
  5. 5 . The coated roofing granule according to claim 1 , wherein the coated roofing granule exhibits a granule color having a b value, as measured by a Hunter L, a, and b color scale, that is 70 percent to 95 percent of a b value of the roofing granule without the post-treatment coating.
  6. 6 . The coated roofing granule according to claim 5 , wherein the coated roofing granule exhibits a granule color having a b value, as measured by a Hunter L, a, and b color scale, that is 85 percent to 95 percent of a b value of the roofing granule without the post-treatment coating.
  7. 7 . The coated roofing granule according to claim 1 , wherein the at least one silicon-containing oligomer or silicon-containing polymer is at least one of polyoctyltrimethoxysilane, potassium methyl siliconate, polymethylhydrogensiloxane, methyl siloxane, aminofunctional polydimethylsiloxane, aminoalkyl polydimethylsiloxane, polymethylsiloxane, potassium propylsilanetriolate, and combinations thereof.
  8. 8 . The coated roofing granule according to claim 1 , wherein the acrylic resin comprises polyacrylates, acrylic-styrene polymers, vinyl-acrylic polymers, an aqueous acrylic emulsion, or combinations thereof.
  9. 9 . The coated roofing granule according to claim 1 , wherein the coated roofing granule exhibits an amount of staining of 0 to 5 after 24 hours.
  10. 10 . The coated roofing granule according to claim 1 , wherein the at least one silicon-containing oligomer or silicon-containing polymer is present in an amount of 0.01 to pounds 1 pound per ton of roofing granules.
  11. 11 . The coated roofing granule according to claim 1 , wherein the acrylic resin is present in an amount of 0.1 to 2 pounds per ton of roofing granules.
  12. 12 . The coated roofing granule according to claim 1 , wherein the coated roofing granule exhibits a dust content of 1 to 10.
  13. 13 . The coated roofing granule according to claim 1 , wherein the roofing granule is a preheated granule that is preheated to an elevated temperature of 70° F. to 520° F.
  14. 14 . A roofing material comprising: (a) a substrate; (b) coated roofing granules applied to the substrate; wherein the coated roofing granules comprise roofing granules coated with a post-treatment coating comprising: (i) at least one silicon-containing oligomer or silicon-containing polymer that is present in an amount of 0.01 to 5 pounds per ton of roofing granule, and (ii) an acrylic resin that is present in an amount of 0.1 to 5 pounds per ton of roofing granules, wherein the coating is substantially free of water.
  15. 15 . The roofing material according to claim 14 , wherein the coated roofing granules further comprise petroleum oil.
  16. 16 . The roofing material according to claim 14 , wherein the coated roofing granules exhibit a total solar reflectance that is 90 percent to 100 percent of the total solar reflectance of the roofing granules without the post-treatment coating.
  17. 17 . The roofing material according to claim 16 , wherein the coated roofing granules exhibit a total solar reflectance that is equal to the total solar reflectance of the roofing granules without the post-treatment coating.
  18. 18 . The roofing material according to claim 14 , wherein the coated roofing granules exhibit a granule color having an L value, as measured by a Hunter L, a, and b color scale, that is 90 percent to 100 percent of an L value of the roofing granules without the post-treatment coating.
  19. 19 . The roofing material according to claim 14 , wherein the coated roofing granules exhibit a granule color having a b value, as measured by a Hunter L, a, and b color scale, that is 70 percent to 95 percent of a b value of the roofing granules without the post-treatment coating.
  20. 20 . The roofing material according to claim 19 , wherein the coated roofing granules exhibit a granule color having a b value, as measured by a Hunter L, a, and b color scale, that is 85 percent to 95 percent of a b value of the roofing granules without the post-treatment coating.

Description

FIELD OF THE INVENTION This invention relates to coated roofing granules, roofing materials made therefrom, and methods of preparing such coated roofing granules. By coating roofing granules with an aqueous coating that includes water, a silicon-containing oligomer or polymer, and an acrylic resin, coated roofing granules can be prepared that exhibit reduced staining as compared to traditional roofing granules that are treated with petroleum oil. Roofing materials, such as, e.g., shingles, made using these coated roofing granules also exhibit superior properties of, for example, reduced staining, improved color, improved solar reflectance, water repellency, and/or reduced dust content, as compared to roofing materials having traditional roofing granules that are treated with petroleum oil. BACKGROUND OF THE INVENTION Traditional roofing materials, such as, e.g., shingles, are based upon a glass or felt mat that is coated and impregnated with an asphalt-based composition that is coated with granules. The granules serve to protect and provide coloring to the asphalt-based roofing material. For example, granules serve to provide coloring to shingles and rolled roofing products and thus, to the roof itself. Additionally, granules generally protect the underlying asphalt coating from damage due to exposure to light, in particular, ultraviolet (UV) light. That is, the granules reflect light and protect the asphalt from deterioration by photo-degradation. In addition, the granules improve fire resistance and weathering characteristics. In general, granules are embedded in the coating asphalt by the application of pressure and are retained therein by adherence to the asphalt. In asphalt-based roofing materials, as granules are secured to the asphalt surface, there is a tendency for oils in the asphalt surface to creep onto or be adsorbed on the granules' surfaces. This creeping or adsorption of the asphalt oils on the granules' surface causes discoloration or staining of the granules and hence reduces the aesthetic effect of the roofing materials. There is thus a need for an aqueous coating for roofing granules that results in coated roofing granules that exhibit reduced staining, as well as improved color, improved solar reflectance, water repellency, and/or reduced dust content, as compared to traditional roofing granules that are treated with petroleum oil. SUMMARY OF THE INVENTION One embodiment of this invention pertains to a method of coating roofing granules that includes (a) obtaining roofing granules and (b) applying a coating to the roofing granules to form coated roofing granules, with the coating comprising (i) water, (ii) at least one silicon-containing oligomer or silicon-containing polymer, and (iii) an acrylic resin having a glass transition temperature of −18° C. to 60° C. When the coated roofing granules are applied to an asphalt shingle, the coated roofing granules exhibit reduced staining as compared to roofing granules that are treated with petroleum oil. In one embodiment, the at least one silicon-containing oligomer or silicon-containing polymer is at least one of polyoctyltrimethoxysilane, potassium methyl siliconate, polymethylhydrogensiloxane, methyl siloxane, aminofunctional polydimethylsiloxane, aminoalkyl polydimethylsiloxane, polymethylsiloxane, potassium propylsilanetriolate, and combinations thereof. In one embodiment, the acrylic resin comprises an emulsion or dispersion of polyacrylates, acrylic-styrene polymers, vinyl-acrylic polymers, or combinations thereof. In one embodiment, the at least one silicon-containing oligomer or silicon-containing polymer is present in an amount of 0.01 to 5 pounds per ton of the roofing granules. In another embodiment, the at least one silicon-containing oligomer or silicon-containing polymer is present in an amount of 0.1 to 1 pounds per ton of the roofing granules. In some embodiments, the at least one silicon-containing oligomer or silicon-containing polymer is present in an amount of 0.5 to 1 pounds per ton of the roofing granules. In another embodiment, the at least one silicon-containing oligomer or silicon-containing polymer is present in an amount of 0.25 to 0.5 pounds per ton of the roofing granules. In one embodiment, the acrylic resin is present in an amount of 0.1 to 10 pounds per ton of the roofing granules. In another embodiment, the acrylic resin is present in an amount of 0.5 to 2 pounds per ton of the roofing granules. In one embodiment, the water is present in an amount of 5 to 100 pounds per ton of the roofing granules. In another embodiment, the water is present in an amount of 10 to 30 pounds per ton of the roofing granules. In some embodiments, the water is present in an amount of 20 to 30 pounds per ton of the roofing granules. In one embodiment, the method further comprises heating the roofing granules prior to applying the coating to the roofing granules. In one embodiment, the method further comprises preparing the coating