Crack inhibitor for tape joint compositions
AssigneeThe Dow Chemical Company
InventorLarry N. Hyman
Life of this patent
Estimating the term…
Abstract
The use of calcium oxide or calcium hydroxide as a crack-inhibiting additive for tape joint compositions is disclosed. Tape joint compositions containing calcium oxide or calcium hydroxide maintain their workability while experiencing less cracking upon drying.
Claims3
A dry powder composition suitable on admixture with water for adhering and covering wallboard joint tapes which comprises from about 40 to about 95 percent limestone, from about 2 to about 30 percent mica, from about 2 to about 30 percent clay, from about 2 to about 15 percent of a binder, from about 0.2 to about 3.0 percent of a water-soluble, surface-treated cellulose ether and from about 0.08 to about 1.53 percent calcium oxide, calcium hydroxide or a mixture thereof, wherein the percent is based on the total weight of the dry components.
A tape joint composition having limestone, mica, clay and a binder as principle ingredients, the improvement which comprises using an effective amount of a crack inhibiting additive wherein the additive is a mixture of
- a. between about 15 to about 80 weight percent of a surface-treated cellulose ether;
- and
- b. between 20 to about 85 weight percent, of calcium oxide, calcium hydroxide or a mixture thereof,
- wherein the weight percent is based on the
- total weight of the additive.
Dependencies are inferred from the claim text.