Calcium sulfate slurries including cationic starch, methods for using them and articles made from them

Abstract

The present disclosure relates more particularly to calcium sulfate-based slurries useful, for example, in making gypsum boards for building construction, as well as methods for using them, e.g., to make gypsum boards, in one aspect, the present disclosure provides a calcium sulfate slurry composition comprising calcium sulfate present substantially in the form of one or more hydrates, the calcium sulfate being present in an amount in the range of 70-99.8 wt % on a dry basis, calculated as stucco; and a cationic starch present in an amount of 0.10-10 wt % of the amount of calcium sulfate as stucco on a dry basis, the cationic starch being substituted with amine and/or ammonium groups and having a % N value in the range of 0.10 wt. % to 2 wt %, and an RVA viscosity value of at least 100 cP at 65° C. and 16 wt %; and water, in an amount sufficient to form a slurry. The disclosure also provides gypsum-based materials useful as building materials, e.g., for use as building boards in construction of walls and ceilings of buildings.

Dependencies are inferred from the claim text.