Roofing granules with enhanced algicidal post treatment

Claim 1

ALGICIDAL ROOFING GRANULES CAPABLE OF INHIBITING OR PREVENTING THE GROWTH OF DISCOLORING ALGAE AND FUNGI ORGANISMS UPON EXPOSURE OF ROOFING SURFACES CONTAINING SUCH GRANULES TO ATMOSPHERIC WEATHERING FOR EXTENDED PERIODS OF TIME, COMPRISING: A. BASE MINERAL GRANULES, B. A MOISTURE PERMEABLE, DURABLE, WATER INSOLUBILIZED PIGMENTED, FIRED, INORGANIC ALKALI METAL SILICATE-CLAY COATING ON SAID BASE GRANULES, C. A PROCESSING OIL COMPOSITION PRESENT IN AN AMOUNT WITHIN THE RANGE OF FROM ABOUT 1/4 GALLON TO ABOUT 1-1/4 GALLONS PER TON OF BASE GRANULES, SAID PROCESSING OIL FORMING A THIN FILM ON THE SURFACE OF AID COATED GRANULES, SAID PROCESSING OIL HAVING A VISCOSITY WITHIN THE RANGE OF FROM ABOUT 525 TO ABOUT 950 SUS. MEASURED AT 100*F, AND D. COPPER SILICATE IN THE OIL FILM AND ADHERING TO THE SURFACE OF SAID GRANULE COATING, SAID COPPER SILICATE HAVING A PARTICLE SIZE NOT EXCEEDING ABOUT 100 MESH AND BEING PRESENT IN AMOUNTS WITHIN THE RANGE OF FROM ABOUT 0.05% TO ABOUT 1.0% BY WEIGHT BASED ON THE WEIGHT OF THE BASE MINERAL GRANULES, METALLIC COPPER IONS BEING LEACHABLE FROM SAID COPPER SILICATE UPON EXPOSURE THEREOF TO MOISTURE DURING ATMOSPHERIC WEATHERING, WHEREBY THE WEATHERING AWAY OF SAID PROCESSING OIL UPON ATMOSPHERIC EXPOSURE OF ROOFING SURFACES INCORPORATING SAID GRANULES DOES NOT ADVERSELY AFFECT THE ENHANCED ADHERENCE OF SAID COPPER SILICATE TO SAID GRANULE COATING, THE PRESENCE OF MOISTURE DURING PERIODS OF RAIN AND DEW CAUSING IONIZATION OF SAID COPPER SILICATER WITH THE RESULTING METALLIC IONS BEING SLOWLY LEACHED FROM SAID GRANULES TO RETARD THE GROWTH OF ALGAE AND FUNGI, THUS ENHANCING THE RESISTANCE OF ROOFING SURFACES CONTAINING SUCH GRANULES TO DISCOLORATION DURING EXTENDED PERIODS OF EXPOSURE TO ATMOSPHERIC WEATHERING.