Roofing granules with high solar reflectance, roofing products with high solar reflectance, and processes for producing same

• US 10,246,879 B2
• Filed: 07/15/2016
• Issued: 04/02/2019
• Est. Priority Date: 05/24/2007
• Status: Active Grant

• Current Assignee: Certainteed, LLC (Compagnie de Saint-Gobain SA)
• Original Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Inventors: Shiao, Ming Liang, Hong, Keith C., Stephens, Walter T.
• Primary Examiner(s): Le, Hoa (Holly)
• Application Number:
  US15/211,085
• Publication Number:
  US 20160326746A1
• Time in Patent Office: 991 Days
• Field of Search: 427186, 427189, 427215, 427218, 427220, 4273722, 4273977, 4273978
• CPC Class Codes: C04B 14/106 Kaolin
• CPC Class Codes: C04B 14/305 Titanium oxide, e.g. titanates
• CPC Class Codes: C04B 18/021 agglomerated by a mineral binder, e.g. cement
• CPC Class Codes: C04B 18/023 Fired or melted materials
• CPC Class Codes: C04B 2111/00586 Roofing materials
• CPC Class Codes: C04B 2111/80 Optical properties, e.g. transparency or reflexibility
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3427 Silicates other than clay, e.g. water glass
• 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 2235/48 Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/9646 Optical properties
• CPC Class Codes: C04B 33/04 Clay; Kaolin
• CPC Class Codes: C04B 33/14 Colouring matters
• CPC Class Codes: C04B 35/62695 Granulation or pelletising devices for shaping artificial aggregates from ceramic mixtures B28B1/004
• CPC Class Codes: C04B 35/62821 Titanium oxide
• CPC Class Codes: C04B 35/6316 Binders based on silicon compounds
• CPC Class Codes: C04B 35/636 Polysaccharides or derivatives thereof
• CPC Class Codes: C04B 35/6365 Cellulose or derivatives thereof
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• 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: 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 428/2982 : Particulate matter [e.g., sphere, flake, etc.]
• CPC Class Codes: Y10T 428/2993 : Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Abstract

Solar reflective roofing granules include a binder and inert mineral particles, with solar reflective particles dispersed in the binder. An agglomeration process preferentially disposes the solar reflective particles at a desired depth within or beneath the surface of the granules.

Claims

1. A process for preparing solar reflective roofing granules, the process comprising:

(a) providing an inorganic binder and inert mineral particles to form a mixture;

(b) forming the mixture into uncured granule bodies having an exterior surface;

(c) adhering solar reflective particles only at or proximate to the exterior surface of the uncured granule bodies; and

(d) firing the binder to provide the solar reflective roofing granules having the solar reflective particles only at or proximate to the exterior surfaces thereof.

2. A process according to claim 1 wherein the solar reflective particles are mechanically adhered to the exterior surface of the uncured granule bodies.

3. A process according to claim 1, further comprising mixing the solar reflective particles with a fluid carrier to form a paste and adhering the solar reflective particles to the exterior surface of the granule bodies by applying the paste to the exterior surface of the granule bodies.

4. A process according to claim 1 further comprising sizing the uncured granules by screening.

5. A process according to claim 1 further comprising surface treating the cured roofing granules.

6. A process according to claim 1 wherein the inert mineral particles comprise uncalcined kaolin, the binder comprises metal silicate, and the binder is cured by heating the uncured granules at from about 500 degrees C. to 800 degrees C.

7. A process for preparing solar reflective roofing granules, the process comprising:

(a) providing an inorganic binder, ceramic particles and solar reflective particles;

(b) dispersing the ceramic particles and the solar reflective particles in the inorganic binder to form a mixture;

(c) forming the mixture into uncured granules, each uncured granule having a plurality of solar reflective particles homogeneously dispersed with a plurality of ceramic particles; and

(d) firing the uncured granules to form cured roofing granules, each cured roofing granule including a plurality of the solar reflective particles at or proximate to an exterior surface thereof.

8. The process according to claim 7 wherein the ceramic particles have an average particle size of from about 0.1 micrometers to about 40 micrometers.

9. A process according to claim 7 further comprising selecting the solar reflective particles to provide at least 60 percent solar reflectance to the cured roofing granules.

10. A process according to claim 7 further comprising sizing the uncured granules by screening.

11. A process for preparing solar reflective roofing granules, the process comprising:

(a) providing an inorganic binder and ceramic particles;

(b) forming the ceramic particles and inorganic binder into uncured granule bodies having an exterior surface;

(c) adhering solar reflective particles only at or proximate to the exterior surface of the uncured granule bodies; and

(d) sintering the uncured granule bodies to form solar reflective roofing granules having the solar reflective particles only at or proximate to the exterior surfaces thereof.

12. A process according to claim 11 wherein the solar reflective particles are mechanically adhered to the exterior surface of the uncured granule bodies.

13. A process according to claim 11 further comprising providing a sintering binder and mixing the sintering binder with the ceramic particles to form a mixture and subsequently forming the mixture including the ceramic particles into uncured granule bodies.