Clay-free, asbestos-free and glass microbubble-free drying type joint compounds

Abstract

A clay-free, asbestos-free and glass microbubble-free, drying type Joint compound containing an in-situ or associative thickener as a substitute for asbestos and any clay substitute therefor. In particular, these drying type joint compounds contain no attapulgus clay thereby improving viscosity stability, crack resistance and shrinkage. The lightweight joint compounds contain treated expanded perlite, treated to render it water-insensitive. The preferred in-situ thickeners are acidic acrylate copolymers. It has been found that the in-situ thickeners should be used in combination with the normal cellulosic thickeners used in joint compounds Instead of as replacements therefor. The joint compounds contain the usual fillers and latex emulsion binders, with at least about 50% by weight of the drying type joint compound being a filler selected from the group consisting of calcium carbonate and calcium sulfate dihydrate.

Dependencies are inferred from the claim text.