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US 4,049,866 AGranted
By-product gypsum fillers for mica-free joint compounds
AssigneeUnited States Gypsum Company
InventorsMarvin K. Lane, Winton C. Anderson
Life of this patent
Estimating the term…
Abstract
A filler for a mica-free joint compound, comprising by-product gypsum having a mean particle size between about 11 and about 12 microns, a percentage by weight of particles smaller than 1 micron of between about 5 and about 6.5, and a packed dry bulk volume no greater than about 93 cc. per 100 grams.
Claims4
A filler for a crack-resistant, drying type joint compound, consisting essentially of calcium sulfate dihydrate synthetically produced from the citric acid process and further processed to have a particle size distribution characterized by
- a mean particle size of between about 11 and about 12 microns,
- particles having a size smaller than one micron comprising between about 5% and about 6.5% by weight of the filler, and
- a packed dry bulk volume no greater than about 93 cc. per 100 grams.
Dependencies are inferred from the claim text.