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US 8,034,432 B2Granted
Roofing granules of enhanced solar reflectance
AssigneeISP Investments Inc.
InventorIngo B. Joedicke
Life of this patent
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Abstract
Roofing granules, methods for their preparation, having a Total Solar Reflectance of at least 25% on a substrate or carrier.
Claims14
Colored granules comprising:
- (a) a base material of crushed and sized mineral aggregates in the form of granules;
- and
- (b) an insolubilized coating material covering said granules comprising:
- (i) dark IR-reflective pigments;
- and
- (ii) coarse non-pigmentary titanium dioxide of particle size distribution:
- 100% less than 40 microns (−325 mesh)
- 50-100% less than 10 microns
- 0-15% less than 1 micron;
- wherein when said colored granules have a Hunter Lightness L>/=25.0, the colored granules have a Total Solar Reflectance of at least 25% and when said colored granules have a Hunter Lightness L<25.0, the colored granules have a Total Solar Reflectance of at least 20%.
7 more elements
A method of preparing colored granules comprising the steps of:
- (a) crushing and sizing a mineral aggregate;
- (b) coating the granules in one or multiple applications, with a semi-ceramic composition comprising in PPT units:
- 40-60 water
- 55 to 100 sodium silicate solution
- 50 to 150 coarse TiO2
- 0 to 50 IR-reflective dark pigments
- 0 to 50 IR-reflective tint pigments
- 20 to 30 Kaolin clay,
- (c) combining the components in (b) above with suitable mixing equipment into a coating composition slurry;
- (d) applying the slurry to the base aggregate to produce uncured color-coated granules;
- (e) pre-drying the uncured color-coated granules by adjusting the temperature and air flow to reduce their moisture content to about 0.2-0.5%;
- (f) kiln-firing the uncured granules at 500° F. to 1000° F. to form an insolubilized silicate-clay matrix in which the IR-reflective pigments and coarse titanium dioxide particles are uniformly distributed;
- (g) cooling the fired, color-coated granules to reduce their temperature;
- (h) optionally repeating steps (c) through (g) to adjust the thickness and composition of the final coating to optimize reflective properties and visual appearance;
- (i) optionally applying a pickling agent to aid coating insolubilization;
- and
- (j) treating the finished granules to impart dust control to improve asphalt adhesion,
- wherein when said colored granules have a Hunter Lightness L>/=25.0, the colored granules have a Total Solar Reflectance of at least 25% and when said colored granules have a Hunter Lightness L<25.0, the colored granules have a Total Solar Reflectance of at least 20%.
15 more elements
Colored granules comprising:
- (a) a base material of crushed and sized mineral aggregates in the form of granules;
- and
- (b) an insolubilized coating material covering said granules comprising:
- (i) dark IR-reflective pigments;
- and
- (ii) coarse non-pigmentary titanium dioxide of particle size distribution:
- 100% less than 40 microns (−325 mesh)
- 50-100% less than 10 microns
- 0-15% less than 1 micron.
6 more elements
Dependencies are inferred from the claim text.