A process for preparing powdered dispersants comprising at least 90% by weight of at least one copolymer CP of the polycarboxylate ether type. The powdered dispersants can be easily dispersed in water. The invention also relates to the use of such powdered dispersants in mineral binder compositions, in particular dry mortars, concrete or gypsum formulations.

A process for preparing powdered dispersants comprising at least 90% by weight of at least one copolymer CP of the polycarboxylate ether type. The powdered dispersants can be easily dispersed in water. The invention also relates to the use of such powdered dispersants in mineral binder compositions, in particular dry mortars, concrete or gypsum formulations.

Gypsum board having improved performance is obtained by controlling the distribution of starch in the gypsum core of the board and the gelling temperature of the starch. Starch migration in the board is controlled by the degree of acid-modification, to adjust the starch viscosity profile. The starch gelling temperature is controlled by chemical modification of the starch —OH groups.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

A dental gypsum slurry includes water and a dental gypsum powder containing hemihydrate gypsum and a polycarboxylic acid salt-based water-reducing agent, wherein a powder-water ratio of the water to the dental gypsum powder is 0.24 to 0.50, and when the water and the dental gypsum powder being mixed are poured up to a height of 50 mm in a cylindrical mold having an inner diameter of 35 mm, which is vertically placed on a flat surface, and then, the cylindrical mold is pulled upward at 10 mm/s at 30 seconds after start of mixing so that a mixture spreads planarly, the diameter of the mixture is 141.4 mm or more.

A dental gypsum slurry includes water and a dental gypsum powder containing hemihydrate gypsum and a polycarboxylic acid salt-based water-reducing agent, wherein a powder-water ratio of the water to the dental gypsum powder is 0.24 to 0.50, and when the water and the dental gypsum powder being mixed are poured up to a height of 50 mm in a cylindrical mold having an inner diameter of 35 mm, which is vertically placed on a flat surface, and then, the cylindrical mold is pulled upward at 10 mm/s at 30 seconds after start of mixing so that a mixture spreads planarly, the diameter of the mixture is 141.4 mm or more.

A high temperature sag resistant lightweight wallboard. The addition of a small amount of urea (about 0.1%) significantly improves the high-temperature sag resistance on Type X gypsum wallboards. These gypsum wallboards may have a board weight of less than 2100 lbs/msf when cast to have an overall 5.8 inch thickness, and may include glass fibers and/or mineral wool. Also, methods of making the gypsum wallboard and a wall system for employing the gypsum wallboard.

A high temperature sag resistant lightweight wallboard. The addition of a small amount of urea (about 0.1%) significantly improves the high-temperature sag resistance on Type X gypsum wallboards. These gypsum wallboards may have a board weight of less than 2100 lbs/msf when cast to have an overall 5.8 inch thickness, and may include glass fibers and/or mineral wool. Also, methods of making the gypsum wallboard and a wall system for employing the gypsum wallboard.

The present disclosure relates generally to plaster wall panels, for example, suitable for covering interior wall frames. The present disclosure relates more particularly to a plaster wall panel including a first plaster layer, a second plaster layer, and a damping layer disposed between the first and second plaster layers. The first plaster layer has a first thickness and is composed of a first plaster material that has a first material property. The second plaster layer has a second thickness and is composed of a second plaster material that has a second material property. The first thickness is smaller than the second thickness, and the first and second material properties are different.

The present disclosure relates generally to plaster wall panels, for example, suitable for covering interior wall frames. The present disclosure relates more particularly to a plaster wall panel including a first plaster layer, a second plaster layer, and a damping layer disposed between the first and second plaster layers. The first plaster layer has a first thickness and is composed of a first plaster material that has a first material property. The second plaster layer has a second thickness and is composed of a second plaster material that has a second material property. The first thickness is smaller than the second thickness, and the first and second material properties are different.