ALGAE RESISTANT ROOFING GRANULES WITH CONTROLLED ALGAECIDE LEACHING RATES, ALGAE RESISTANT SHINGLES, AND PROCESS FOR PRODUCING SAME

摘要

Algae-resistant roofing granules are formed by coating mineral particles wit h a clay-silicate binder including a metal oxide algaecide and small organic particles. When the particles are heated to cure the binder, the organic particles pyrolyse to form pores in the coating. Release of the algaecide is controlled by the structure of the granules.