SOLAR HEAT-REFLECTIVE ROOFING GRANULES, SOLAR HEAT-REFLECTIVE SHINGLES, AND PROCESS FOR PRODUCING THE SAME

• US 20110086201A1
• Filed: 09/21/2010
• Published: 04/14/2011
• Est. Priority Date: 09/22/2009
• Status: Active Grant

• Current Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Original Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Inventors: Fuss, Tihana, Stephens, Walter T., Kalkanoglu, Husnu M., Shiao, Ming Liang
• Granted Patent: US 8,722,140 B2
• Time in Patent Office: Days
• US Class Current: 428/148
• CPC Class Codes: C03C 10/00 Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/349 Clays, e.g. bentonites, smectites such as montmorillonite, vermiculites or kaolines, e.g. illite, talc or sepiolite
• CPC Class Codes: C04B 2235/528 Spheres
• CPC Class Codes: C04B 2235/5427 millimeter or submillimeter sized, i.e. larger than 0,1 mm
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5463 Particle size distributions
• CPC Class Codes: C04B 2235/5472 Bimodal, multi-modal or multi-fraction
• CPC Class Codes: C04B 2235/5481 Monomodal
• CPC Class Codes: C04B 2235/95 Products characterised by their size, e.g. microceramics
• CPC Class Codes: C04B 2235/9646 Optical properties
• CPC Class Codes: C04B 2235/9661 Colour
• CPC Class Codes: C04B 33/04 Clay; Kaolin
• CPC Class Codes: C04B 33/32 Burning methods
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 35/18 rich in aluminium oxide
• CPC Class Codes: C04B 35/62695 Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C04B 35/636 Polysaccharides or derivatives thereof
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: E04D 1/16 of ceramics, glass or concrete, with or without reinforcement
• CPC Class Codes: E04D 1/20 : of plastics; of asphalt; of fibrous materials
• CPC Class Codes: E04D 2001/005 : the roofing elements having a granulated surface
• 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 428/24413 : Metal or metal compound
• CPC Class Codes: Y10T 428/24421 : Silicon containing

Abstract

A process for preparing roofing granules includes forming kaolin clay into green granules and sintering the green granules at a temperature of at least 900 degrees Celsius to cure the green granules until the crystalline content of the sintered granules is at least ten percent as determined by x-ray diffraction.

Claims

1. A process for forming bituminous roofing products with high solar heat reflectance, the process comprising:

(a) providing a ceramic-forming material comprising at least one aluminosilicate;

(b) forming the ceramic-forming material into green granules;

(c) sintering the green granules at a temperature of at least 900 degrees Celsius until the crystalline content of the sintered granules is at least ten percent as determined by x-ray diffraction;

(d) providing a bituminous roofing sheet material having an upper surface; and

(e) applying the sintered granules to the upper surface of a bituminous roofing sheet material.

2. A process according to claim 1, wherein the green granules are sintered until the crystalline content of the granules is at least 70 percent.

3. A process according to claim 2, wherein the granules are sintered at a temperature of at least 1450 degrees Celsius until the crystalline content of the granules is about 100 percent as determined by x-ray diffraction.

4. A process according to claim 1, the at least one aluminosilicate comprising kaolin clay.

5. A process according to claim 1, the at least one aluminosilicate comprising bauxite.

6. A process according to claim 1, wherein the ceramic-forming material is formed into green granules by mixing the ceramic-forming material with a liquid to form a mixture, the mixture being formed into pellets, and the pellets being screened to provide green granules.

7. A process according to claim 1, further comprising pressing the sintered granules into the upper surface of the bituminous roofing sheet material to embed the sintered granules in the upper surface of the roofing sheet material.

8. A process according to claim 1, wherein the ceramic-forming material is formed into green granules having a predetermined particle-size distribution.

9. A process according to claim 8 wherein the ceramic-forming material is formed into at least two different classes of green granules, each class of green granule being characterized by a predetermined average particle size, the green granules being sintered to provide at least two size classes of sintered granules.

10. A process according to claim 1, further comprising mixing at least two classes of granules, each class being characterized by a different particle-size distribution.

11. A process according to claim 1, wherein the shape of the granules and the granule particle-size distribution are selected to provide at least 85 percent surface coverage when the roofing granules are applied to upper surface of a bituminous roofing sheet material.

12. A process according to claim 1 wherein the ceramic-forming material is formed into spherical green granules.

13. A process according to claim 1 wherein the ceramic-forming material is formed into plate-like green granules.

14. A process according to claim 1 further comprising selecting sintered granules from at least two different classes prior to applying the sintered granules in the upper surface of the bituminous roofing sheet material, the sintered granules being selected to provide a predetermined surface coverage of the bituminous sheet material.

15. A process according to claim 14 wherein at least two different classes of sintered granules are applied sequentially to the upper surface of the bituminous sheet roofing material.

16. A process according to claim 14 further comprising mixing the at least two classes of sintered granules prior to applying the sintered granules to the upper surface of the bituminous sheet material.

17. A process according to claim 1 further comprising applying conventional colored roofing granules in the bituminous roofing sheet material.

18. A process according to claim 1 wherein the sintered granules are mixed with a liquid binder composition prior to applying the sintered granules to the upper surface of the bituminous roofing sheet material.

19. A process according to claim 1 further comprising applying a liquid binder composition to the upper surface of the bituminous roofing sheet material after the sintered granules have been applied.

20. A process according to claim 18 wherein the liquid binder composition is selected from the group consisting of acrylic emulsions, acrylic solutions, thermoplastic polymers, fluoropolymer emulsions, epoxy resins, UV curable resins, radiation curable resins, alkaline metal silicates, sol-gel solutions, silicone resins, and silica binders.

21. A process according to claim 19 wherein the liquid binder composition is selected from the group consisting of acrylic emulsions, acrylic solutions, thermoplastic polymers, fluoropolymer emulsions, epoxy resins, UV curable resins, radiation curable resins, alkaline metal silicates, sol-gel solutions, silicone resins, and silica binders.

22. A bituminous roofing product prepared according the process of claim 1.

23. A process for forming bituminous roofing products with high solar heat reflectance, the process comprising:

(a) providing a ceramic-forming material comprising at least one aluminosilicate;

(b) providing base particles comprising material thermally stable up to a temperature of at least 900 degrees Celsius;

(c) applying the ceramic-forming material to the base particles to form a green coating layer on the base particles to form green granules;

(d) sintering the green granules at a temperature of at least 900 degrees Celsius until the crystalline content of the coating layer of the granules is at least ten percent as determined by x-ray diffraction;

(e) providing a bituminous roofing sheet material having an upper surface; and

(f) applying the sintered granules in the upper surface of a bituminous roofing sheet material.

24. A process for forming bituminous roofing products with high solar heat reflectance, the process comprising:

(a) providing a ceramic-forming material comprising at least one aluminosilicate;

(b) forming the ceramic-forming material into green granules;

(c) sintering the green granules at a temperature of at least 900 degrees Celsius until the crystalline content of the sintered granules is at least ten percent as determined by x-ray diffraction;

(d) providing a matrix material for securing the sintered granules;

(e) forming a solar reflective sheet comprising sintered granules and matrix material;

(f) providing a bituminous roofing sheet material with an upper surface; and

(g) applying the solar reflective sheet to the upper surface of a bituminous roofing sheet material.

(h) applying the solar reflective sheet to the upper surface of a bituminous roofing sheet material.