Coated Roofing Granules, Roofing Materials Made Therefrom And Methods Of Preparing Coated Roofing Granules
Patent No. US11136760 (titled "Coated Roofing Granules, Roofing Materials Made Therefrom And Methods Of Preparing Coated Roofing Granules") was filed by Deutsche Bank Ag New York Branch on Feb 27, 2020.
What is this patent about?
’760 is related to the field of roofing materials, specifically addressing the problem of staining and discoloration of roofing granules used in asphalt shingles. Traditional roofing granules are treated with petroleum oil to improve their adherence to the asphalt, but this can lead to the oil migrating to the surface and causing unsightly stains. The invention aims to provide an alternative coating that reduces staining while maintaining or improving other desirable properties of the granules.
The underlying idea behind ’760 is to replace the petroleum oil treatment with an aqueous coating containing a silicon-containing oligomer or polymer and an acrylic resin . This combination is designed to provide a protective layer that prevents asphalt oils from migrating to the surface of the granules, thereby reducing staining. The water acts as a carrier for the other components, allowing for easier application and dispersion.
The claims of ’760 focus on a method of coating roofing granules. The method involves heating the granules, applying an aqueous coating comprising water, a silicon-containing oligomer or polymer, and an acrylic resin, and optionally applying petroleum oil after the aqueous coating. The key feature is the use of the silicon-containing compound and acrylic resin in an aqueous solution to reduce staining compared to traditional oil-based treatments.
In practice, the roofing granules are first heated to a temperature between 150°F and 520°F. This preheating step likely helps to improve the adhesion of the aqueous coating to the granules. The aqueous coating is then applied, and the water evaporates, leaving behind a film of the silicon-containing compound and acrylic resin. In some embodiments, a petroleum oil "top dressing" is applied after the aqueous coating to further enhance the granules' properties.
The differentiation from prior approaches lies in the replacement of petroleum oil as the primary coating agent with an aqueous solution of a silicon-containing compound and an acrylic resin. This approach aims to minimize the staining caused by oil migration while potentially improving other properties such as color retention, solar reflectance, water repellency, and dust reduction. The specific combination of these components and the method of application are key to achieving the desired reduction in staining.
How does this patent fit in bigger picture?
Technical landscape at the time
In the early 2020s when ’760 was filed, roofing granules were typically treated with petroleum oil to protect the underlying asphalt coating from UV light and improve fire resistance and weathering characteristics. At a time when staining and discoloration of granules due to oil adsorption was a known problem, systems commonly relied on petroleum-based treatments, and hardware or software constraints made it non-trivial to achieve improved color, solar reflectance, water repellency, and reduced dust content without compromising other performance characteristics.
Novelty and Inventive Step
The examiner approved the application because the prior art did not disclose or make obvious heating roofing granules to an elevated temperature between 150°F and 520°F to obtain heated roofing granules, followed by applying a coating comprising water, a silicon-containing oligomer or polymer, and an acrylic resin to form coated roofing granules.
Claims
This patent contains 14 claims, with claims 1 and 2 being independent. The independent claims are directed to methods of coating roofing granules using a specific coating composition that includes water, a silicon-containing component, and an acrylic resin. The dependent claims generally specify details, ranges, and additional steps related to the method and coating composition defined in the independent claims.
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Date
Description
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US11136760
- Application Number
- US16803544
- Filing Date
- Feb 27, 2020
- Status
- Granted
- Expiry Date
- Feb 27, 2040
- External Links
- Slate, USPTO, Google Patents