Ultra-white silica-based filler
AssigneeCovia Holdings Corporation
InventorsGregory Kenneth Bedford, Claud Eric Westbrook, III
Life of this patent
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Abstract
An ultra-white granular silica-based filler comprises at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the silica-based filler comprises 40 to 80 wt. % cristobalite, 1 to 25 wt. % tridymite, 2-60 wt. % quartz and <5 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is no higher than 50° C. and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98. In addition, an ultra-white powder filler is obtained by milling, grinding or comminuting the ultra-white granular silica-based filler. The ultra-white powder filler exhibits an L* value in the CIELAB color space of 95-98.5.
Claims19
An ultra-white granular silica-based filler comprising at least 99.5 wt. % silica, wherein the crystal structure of the silica is such that the ultra-white granular silica-based filler comprises 33 to 60 wt. % cristobalite, 1 to 25 wt. % tridymite, 30 to 50 wt. % quartz and ≤2 wt. % amorphous silica, wherein the temperature of the ultra-white granular silica-based filler is 50° C. or less and further wherein the ultra-white granular silica-based filler exhibits an L* value in the CIELAB color space of 95-98.
Dependencies are inferred from the claim text.