FIELD: construction.
SUBSTANCE: group of inventions relates to gypsum panels with low mass and density, with good thermal insulating properties, good resistance to heat shrinkage, good fire resistance and, in some aspects of the present invention, good water resistance. Gypsum panel contains a solified gypsum middle layer, located between the two facing sheets, formed from a slurry containing at least water, gypsum building plaster and pregelatinized starch. Starch is present in an amount of from about 0.5 % to about 10 % by weight of the weight of the construction gypsum and effective to increase the hardness of the hardened gypsum middle layer as compared to the gypsum middle layer formed from the slurry, not containing pregelatinized starch. Gypsum building plaster is contained in an amount of approximately 700 lb/kt. f. feet (about 3.4 kg/m2), wherein the gypsum building plaster and water are contained in at least amounts, effective to create a crystalline matrix essentially consisting of calcium sulfate dihydrate. Panel has a density in a range of about 27 to 32 pounds/foot3 (from about 430 to about 513 kg/m3), an average hardness of the middle layer of at least about 11 pounds (about 5 kg) determined in accordance with ASTM C473-09, and a thermal insulation coefficient of at least about 17 minutes. Thickness of the panel is approximately 0.625 inches (about 1.6 cm).
EFFECT: technical result is a decrease in mass and density, an increase in thermal insulation properties, resistance to heat shrinkage, fire resistance, water resistance.
23 cl, 11 ex, 4 dwg, 15 tbl
