Solar heat-reflective roofing granules, solar heat-reflective shingles, and process for producing same

• US 8,361,597 B2
• Filed: 03/27/2008
• Issued: 01/29/2013
• Est. Priority Date: 04/02/2007
• Status: Active Grant

• Current Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Original Assignee: CertainTeed Corp. (Compagnie De Saint-Gobain)
• Inventors: Shiao, Ming Liang, Hong, Keith C., Kalkanoglu, Husnu M., Jacobs, Gregory F.
• Primary Examiner(s): Sample, David
• Assistant Examiner(s): VAN SELL, NATHAN L
• Application Number:
  US12/057,131
• Publication Number:
  US 20080241472A1
• Time in Patent Office: 1,769 Days
• Field of Search: 428/143
• US Class Current: 428/144
• CPC Class Codes: C01P 2006/62 L* (lightness axis)
• CPC Class Codes: C04B 14/04 Silica-rich materials; Silicates
• CPC Class Codes: C04B 14/06 Quartz; Sand
• CPC Class Codes: C04B 14/285 Marble
• CPC Class Codes: C04B 18/141 Slags
• CPC Class Codes: C04B 20/1059 Pigments or precursors thereof
• CPC Class Codes: C04B 20/1066 Oxides, Hydroxides
• CPC Class Codes: C04B 20/1074 Silicates, e.g. glass
• CPC Class Codes: C04B 20/12 Multiple coating or impregnating
• CPC Class Codes: C04B 2111/00586 Roofing materials
• CPC Class Codes: C04B 2111/80 Optical properties, e.g. transparency or reflexibility
• CPC Class Codes: C09C 3/063 Coating
• 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: Y02W 30/91 Use of waste materials as fillers for mortars or concrete
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/24364 with transparent or protective coating
• CPC Class Codes: Y10T 428/24372 Particulate matter
• CPC Class Codes: Y10T 428/2438 Coated
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]
• 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 428/2996 : Glass particles or spheres

Abstract

Solar-reflective roofing granules having improved solar heat-resistance are formed by coating colored mineral particles with a coating composition including titanium dioxide nanoparticles.

Claims

1. Solar heat-reflective roofing granules comprising:

(a) a base particle comprising an inert mineral;

(b) a first coating on the base particle, and

(c) a second coating on the first coating, wherein the second coating comprises a plurality of infrared-reflective metal films.

2. Solar heat-reflective roofing granules according to claim 1 wherein the second coating has an average incident radiation transmission coefficient of at least 80 percent in the range of 400 nanometers to 800 nanometers.

3. Solar heat-reflective roofing granules according to claim 1 wherein the first coating on the base particle comprises a metal oxide colorant.

4. Solar heat-reflective roofing granules according to claim 1 wherein the second coating comprises at least one film formed from a metal selected from the group consisting of silver, gold and copper.

5. Solar heat-reflective roofing granules according to claim 4 wherein the thickness of the second coating is less than about 50 nanometers.

6. Roofing shingles comprising roofing granules according to claim 1.

7. A sheet roofing product comprising:

a bituminous base; and

solar heat reflective roofing granules according to claim 1.