Roofing granules with high solar reflectance, roofing materials with high solar reflectance, and the process of making the same

• US 8,790,778 B2
• Filed: 02/20/2013
• Issued: 07/29/2014
• Est. Priority Date: 12/16/2008
• Status: Active Grant

• Current Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Original Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Inventors: Shiao, Ming Liang, Millberg, Jennifer A., Jacobs, Gregory F.
• Primary Examiner(s): Le, Holly
• Application Number:
  US13/772,214
• Publication Number:
  US 20130161578A1
• Time in Patent Office: 524 Days
• Field of Search: 428403-407, 428145-148, 428/206, 428/208
• US Class Current: 428/403
• CPC Class Codes: B01F 23/811 Heating the mixture
• CPC Class Codes: E04D 2001/005 the roofing elements having a granulated surface
• CPC Class Codes: E04D 5/12 specially modified, e.g. perforated, with granulated surface, with attached pads
• CPC Class Codes: E04D 7/005 characterised by loose or embedded gravel or granules as an outer protection of the roof covering
• CPC Class Codes: G02B 1/00 Optical elements characterised by the material of which they are made; Optical coatings for optical elements
• CPC Class Codes: Y02A 30/254 Roof garden systems; Roof coverings with high solar reflectance
• CPC Class Codes: Y02B 80/00 Architectural or constructional elements improving the thermal performance of buildings
• CPC Class Codes: Y10T 428/2438 Coated
• CPC Class Codes: Y10T 428/24388 Silicon containing coating
• CPC Class Codes: Y10T 428/24405 Polymer or resin [e.g., natural or synthetic rubber, etc.]
• CPC Class Codes: Y10T 428/24413 Metal or metal compound
• CPC Class Codes: Y10T 428/24893 including particulate material
• CPC Class Codes: Y10T 428/24909 Free metal or mineral containing
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]
• CPC Class Codes: Y10T 428/2995 Silane, siloxane or silicone coating
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

Roofing granules include a core having an average ultraviolet transmission of greater than sixty percent and an average near infrared reflectance of greater than sixty percent and a UV coating layer on the exterior surface. The coating provides UV opacity, while the core provides near infrared reflectance.

Claims

1. Roofing granules comprising:

(a) a core having an exterior surface and comprising agglomerate including base particles and an agglomerate binder phase, the base particles having an average ultraviolet transmission of greater than sixty percent and an average near infrared reflectance of greater than sixty percent, and

(b) at least one of;

(1) a UV coating layer to cover the exterior surface, the UV coating layer having an average ultraviolet transmission of less than ten percent and an average transmission in the near infrared and visible ranges of the electromagnetic spectrum of greater than sixty percent, and

(2) the agglomerate binder phase having an average ultraviolet transmission of less than ten percent and an average transmission in the near infrared and visible ranges of the electromagnetic spectrum of greater than sixty percent.

2. Roofing granules according to claim 1, the agglomerate base particles including a first class of base particle having a first refractive index and a second class of base particles having a second refractive index, the first refractive index differing from the second refractive index.

3. Roofing granules according to claim 2, the cores further including infrared radiation scattering voids.

4. Roofing granules according to claim 2 wherein the cores comprise porous inorganic material having an average pore size from about 100 to 2500 nm.

5. Roofing granules according to claim 1, the agglomerate base particles including a first class of base particles having an amorphous structure and a second class of base particles having a crystalline structure.

6. Roofing granules according to claim 5, the cores further including infrared radiation scattering voids.

7. Roofing granules according to claim 5 wherein the cores comprise porous inorganic material having an average pore size from about 100 to 2500 nm.

8. Roofing granules according to claim 1 wherein the agglomerate binder phase comprises a binder and at least one material dispersed in the binder.

9. Roofing granules according to claim 8 wherein the binder has an average ultraviolet transmission of less than ten percent.

10. Roofing granules according to claim 8 wherein the at least one material comprises an ultraviolet absorber selected from the group consisting of organic or inorganic ultraviolet absorbing compounds, organic or inorganic ultraviolet-absorbing particles, and insoluble ultraviolet-absorbing inorganic pigments.

11. Roofing granules according to claim 10 wherein the ultraviolet-absorbing inorganic pigments comprise micronized titanium dioxide, micronized zinc oxide, micronized iron oxide, and micronized cerium oxide.

12. Roofing granules according to claim 10 wherein the insoluble ultraviolet-absorbing inorganic particles comprise titanium oxide nanoparticles, zinc oxide nanoparticles, iron oxide nanoparticles and cerium oxide nanoparticles.

13. Roofing granules according to claim 10 wherein the organic ultraviolet-absorbing particles comprise micronized 2,2′

-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol].

14. Roofing granules according to claim 10 wherein the organic ultraviolet-absorbing compound is selected from the class consisting of triazines, benzotriazoles, benzophenones, vinyl-group containing amides, cinnamic acid amides, diphenyl acrylates, and sulfonated benzimidazoles.

15. Roofing granules according to claim 10 wherein the organic ultraviolet-absorbing compound comprises at least one ultraviolet A absorber and at least one ultraviolet B absorber.

16. Roofing granules according to claim 15 wherein the at least one ultraviolet A absorber is selected from the group consisting of butyl methoxydibenzoylmethane, 5-methyl-2-(1-methylethyl)cyclohexanol-2-aminobenzoate, bis[7,7-dimethyl-oxo-]terephthalylidene dicamphor sulfonic acid, and methylene bis-benzotriazolyl tetramethylbutylphenol.

17. Roofing granules according to claim 15 wherein the at least one ultraviolet B absorber is selected from the group consisting of octyl methoxycinnamate, 2-benzoyl-5-methoxyphenol, ethylhexyl salicylate, 2-cyano-3,3-diphenyl acrylic acid, 3,3,5-trimethylcyclohexanol salicylate, phenylbenzimazole sulfonic acid, 2-ethylhexyl-4-dimethylamino benzoate, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, and p-aminobenozic acid.

18. Roofing granules comprising:

(a) a core having an average ultraviolet transmission of greater than sixty percent and an average near infrared reflectance of greater than sixty percent, the core having an exterior surface, (b) a near infrared-reflective coating layer covering the exterior surface of the core, and (c) a UV coating layer covering the near infrared coating layer, the UV coating layer having an average ultraviolet transmission of less than ten percent and an average transmission in the near infrared and visible ranges of the electromagnetic spectrum of greater than sixty percent.

19. Roofing granules comprising:

(a) a core having an average ultraviolet transmission of greater than sixty percent and an average near infrared reflectance of greater than sixty percent, and at least two coating layers on the core, the at least two coating layers including

(b) a near infrared-reflective coating layer, and (c) a UV coating layer, the UV coating layer having an average ultraviolet transmission of less than ten percent and an average transmission in the near infrared and visible ranges of the electromagnetic spectrum of greater than sixty percent.

20. Roofing granules according to claim 19, the near infrared-reflective coating layer comprising at least one thin metal layer.

21. Roofing granules according to claim 20, the thickness of the near infrared coating layer being selected to maximize the near infrared reflectivity of the near infrared coating layer.

22. Roofing granules according to claim 20, the thickness of the coating formed by the at least one metal layer being selected to maximize the near infrared reflectivity of the near infrared coating layer consistent with achieving a predetermined color tone for the roofing granule.

23. Roofing granules according to claim 20, each of the metal layers being applied by an application process selected from the group consisting of atmospheric plasma deposition, plasma-assisted polymerization, chemical vapor deposition, physical vapor deposition, sputtering, casting, coating, laminating, electroplating, electroless plating, and thermal spraying.

24. Roofing granules according to claim 23, the application process being selected from the group consisting of atmospheric plasma deposition, plasma-assisted polymerization, and physical vapor deposition.

25. Roofing granules according to claim 20, each of the metal layers comprising a material selected from the group consisting of silver, aluminum, copper, zinc, tin, gold, palladium, nickel, and alloys thereof.

26. Roofing granules according to claim 20, at least one metal layer comprising an alloy selected from the group consisting of alloys of silver and copper, and alloys of gold and palladium.