Abstract: The present invention relates to a plaster-based material which includes an agent capable of trapping formaldehyde, in particular a plasterboard intended for the interior fittings of residential buildings. The agent capable of trapping formaldehyde is chosen from ethylene urea and its derivatives, compounds comprising active methylene(s), sulphites, tannins and their mixtures. Another subject-matter of the invention is the use of the said material for reducing the amount of formaldehyde present in the atmosphere inside residential buildings.

Abstract: A gypsum stucco composition comprising the following components finely divided; calcium sulphate hemihydrate in calcined solid beta crystalline form; and in intimate mixture with said finely divided calcium sulphate hemihydrate and mixed therewith no later than calcination to form the hemihydrate, a sulphate salt comprising at least one of ammonium sulphate and aluminium sulphate, in an amount such that when the stucco composition is mixed with water and allowed to set, the resulting set plaster has increased compressive strength, flexural strength and/or E-modulus compared to a set plaster produced from said finely divided calcium sulphate hemihydrate containing no said sulphate salt.

Abstract: A multilayer gypsum board forming device, and a gypsum additive delivery system in which additives are delivered to one or more layers of a multi layered gypsum board panels, including engineered polymers, includes at least one additive assembly connected in-line with a first gypsum delivery receptacle for providing an additive fluid feed into the stream of a first gypsum slurry being transported through said first gypsum delivery receptacle for homogenously adding an additive to the first gypsum slurry, and a second gypsum delivery receptacle transporting a second gypsum slurry, in fluid communication with the mixer providing the first gypsum slurry, having a different set of characteristics from those of the first gypsum slurry. At least one outer surface including a polymeric compound or wax emulsion additive entrained therein essentially encases the core gypsum within two facing layers.