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 Liang Shiao, Anne B. Hardy, James A. Salvatore, Andrew G. Johnson
Life of this patent
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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.
Claims21
An algae-resistant roofing shingle, the shingle comprising a shingle stock material and algae-resistant roofing granules adhered to a shingle stock material, each of the algae-resistant roofing granules comprising:
- (a) a porous, inert base particle comprising agglomerated particles of stone dust having an average particle size in the range of 0.1 microns to 40 microns, bound by a binder, each base particle comprising a plurality of pores exposed at an exterior surface of the base particle and a porosity in the range of 3-30%;
- and
- (b) at least one inorganic algaecide disposed within pores of the base particle.
An algae-resistant roofing shingle, the shingle comprising a shingle stock material and algae-resistant roofing granules adhered to a shingle stock material, each of the algae-resistant roofing comprising stone dust having an average particle size in the range of 0.1 microns to 40 microns and at least one inorganic algaecide, the stone dust and the at least one inorganic algaecide being bound by a binder, the particles having a porosity in the range of 3-30%.
A method for making algae-resistant roofing granules, the method comprising:
- (a) providing porous, inert base particles, each of the base particles comprising agglomerated particles of stone dust having an average particle size in the range of 0.1 microns to 40 microns, bound by a binder, each base particle comprising a plurality of pores exposed at an exterior surface of the base particle and having a porosity in the range of 3-30%;
- and
- (b) disposing at least one inorganic algaecide within pores of the base particles to form algaecide-bearing particles.
Dependencies are inferred from the claim text.