| 摘要 |
This invention relates to a color stable pigment composition for coating hard mineral granules employed for weather surfacing asphalt roofing and siding shingles. The composition is a 40-60% aqueous slurry of pigment containing ferrosoferric oxide and a silicate/clay mixture which is suitable for coating the surface of the mineral granules. The invention also pertains to a process for the manufacture of the coated granules, to the dry coated mineral granule product containing ferrosoferric oxide bonded in a silicate/clay matrix which is suitable for surfacing asphaltic shingles, to the dried composition containing from about 5 to about 50 wt.% total pigment in a silicate/clay matrix in which the pigment contains Fe3O4 in a concentration of between about 2 and about 100% and to a Fe3O4 pigment mixture per se. |
