Algae resistant roofing granules with controlled algaecide leaching rates, algae resistant shingles and process for producing same
AssigneeCertainTeed Corporation
InventorsKeith C. Hong, Husnu M. Kalkanoglu, Ming L. Shiao, Anne B. Hardy, James A. Salvatore, Andrew G. Johnson, JR.
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Abstract
Algae-resistant roofing granules are formed by extruding a mixture of mineral particles and a binder to form porous granule bodies, and algaecide is distributed in the pores. Release of the algaecide is controlled by the structure of the granules.
Claims20
A process for producing algae resistant roofing shingles, the process comprising producing algae-resistant roofing granules, and adhering the granules to a shingle stock material, the algae-resistant roofing granules being produced by a process comprising:
- (a) providing porous, inert base particles;
- and
- (b) providing at least one inorganic algaecide on or within the base particles to form algaecide-bearing particles.
A process for producing algae resistant roofing shingles, the process comprising producing algae-resistant roofing granules, and adhering the granules to a shingle stock material, the algae-resistant roofing granules being produced by a process comprising:
- (a) mixing stone dust, a binder and at least one inorganic algaecide;
- and
- (b) forming the mixture into particles by a forming process selected from press molding, cast molding, injection molding, extrusion, spray granulation, gel casting, and pelletizing.
Dependencies are inferred from the claim text.