Patent ID: 7776462

Claim:
A gypsum board comprising: a gypsum core material comprising calcium sulfate dihydrate and a dispersant consisting essentially of a first and a second repeating unit, wherein said first repeating unit is an olephinic unsaturated mono-carboxylic acid repeating unit or an ester or salt thereof, or an olephinic unsaturated sulphuric acid repeating unit or a salt thereof, and said second repeating unit is of the general formula (I) where R 1 is represented by and wherein R 2 is hydrogen or an aliphatic C 1 to C 5 hydrocarbon group, R 3 is a non-substituted or substituted aryl group and preferably phenyl, and R 4 is hydrogen or an aliphatic C 1 to C 20 hydrocarbon group, a cycloaliphatic C 5 to C 8 hydrocarbon group, a substituted C 6 to C 14 aryl group or a group conforming to the formula wherein R 5 and R 7 , independently of each other, represent an alkyl, aryl, aralkyl or alkylaryl group and R 6 is a divalent alkyl, aryl, aralkyl or alkaryl group, p is 0 to 3, inclusive, m and n are, independently, an integer from 2 to 4, inclusive; x and y are, independently, integers from 55 to 350, inclusive and z is from 0 to 200, inclusive.