Foamed slurry and building panel made therefrom

The method of preparing a gypsum product comprising the steps of:

• forming an aqueous soap mixture having one or more soaps and foam water in an initial concentration by weight of the one or more soaps in the foam water;
• pregenerating foam from the aqueous soap mixture;
• preparing a gypsum slurry by mixing together gauging water, a hydraulic component comprising at least 50 percent calcined gypsum by weight based on the dry weight of the hydraulic component, a defoamer, and a polycarboxylate dispersant;
• combining the slurry and the pregenerated foam to make a foamed gypsum core having a size distribution of voids in the core;
• and
• changing the size distribution of the voids in the core produced in the combining step by carrying out the forming step with a second concentration different from the initial concentration and then carrying out said pregenerating, preparing, and combining steps;
• wherein said polycarboxylate dispersant consists essentially of a first and a second repeating unit, wherein said first repeating unit is an olefinic unsaturated mono-carboxylic acid repeating unit or an ester or salt thereof, or an olefinic unsaturated sulfonic acid repeating unit or a salt thereof, and said second repeating unit is of the general formula (I)
• where R1 is represented by
• and wherein R2 is hydrogen or an aliphatic C1 to C5 hydrocarbon group, R3 is a non-substituted or substituted aryl group, and R4 is hydrogen or an aliphatic C1 to C20 hydrocarbon group, a cycloaliphatic C5 to C8 hydrocarbon group, a substituted C6 to C14 aryl group or a group conforming to the formula
• wherein R5 and R7, independently of each other, represent an alkyl, aryl, aralkyl or alkylaryl group and R6 is a divalent alkyl, aryl, aralkyl or alkaryl group, p is 0, 1, 2, 3, inclusive, m and n are, independently, an integer from 2, 3, 4, 5, inclusive;
• x and y are, independently, integers from 1 to 350, inclusive and z is from 0 to 200, inclusive.