Method of inhibiting algae growth on asphalt shingles
AssigneeMinnesota Mining and Manufacturing Company
InventorsSankar B. Narayan, William T. Fay, Billy L. George, Christine A. Sobon, Mark H. Kayser
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Abstract
A method of inhibiting algae growth on an asphalt shingle surface exposed to varying humidity using a blend of copper-containing algae-resistant granules and non-algae-resistant granules. The copper-containing algae-resistant granules comprise a substrate granule having at least one inner ceramic coating layer comprising cuprous oxide and a seal coating having a thickness covering the inner layer and which is at time t.sub.o devoid of copper.
Claims7
A method of inhibiting algae growth on an asphalt shingle surface exposed to varying humidity using a blend of copper-containing algae-resistant granules and non-algae-resistant granules, the copper-containing algae-resistant granules comprising a substrate granule having at least one inner ceramic coating layer comprising cuprous oxide and a seal coating having a thickness covering the inner layer and which is at time t.sub.o devoid of copper, the method comprising the steps of:
- (a) selecting a period of time t.sub.f during which effective algae inhibition on the surface is to be achieved;
- (b) selecting an initial loading of cuprous oxide in the inner ceramic layer of the copper-containing algae-resistant granules;
- (c) calculating a weight ratio of copper-containing algae-resistant granules to non-algae-resistant granules to achieve a leach rate of copper ions through the seal coating of the copper-containing algae-resistant granules at time t.sub.f necessary to achieve effective algae inhibition on the surface at time t.sub.f ;
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- (d) providing the copper-containing algae-resistant granules and the non-algae-resistant granules in the weight ratio calculated in step (c) on an asphalt shingle surface.
Dependencies are inferred from the claim text.