Lightweight joint compound having improved paintability
AssigneeUnited States Gypsum Company
InventorsArthur W. Struss, Terrance L. Williams, Lawrence T. Eby
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Abstract
Expanded perlite coated with a composition to render the perlite impervious to water, and a joint compound incorporating the same. The perlite is ground prior to expansion to provide subsequently expanded perlite having a mean particle size from about from about 50 to about 70 microns, the joint compound formed from the perlite having greater uniformity in paint gloss appearance between the painted surface of the joint compound and the painted surface of the gypsum wallboard on which the joint compound is applied.
Claims21
A lightweight joint compound having properties suitable for use in finishing joints between the edges of adjacent wallboards, and having improved paintability properties, said joint compound comprising:
- (1) a filler selected from the group consisting of calcium carbonate and calcium sulfate,
- (2) a non-leveling agent,
- (3) expanded perlite which has been treated with a composition to render said perlite water-impervious, said perlite having a mean particle size no greater than about 70 microns and being present in an amount of from about 3.5% to about 25% based on the dry weight of said joint compound,
- (4) a thickener,
- (5) a binder, and
- (6) sufficient water to adjust the viscosity to render said joint compound suitable for use.
Dependencies are inferred from the claim text.