Plaster additive

All of the gluconates can be used as a cement or plaster additive where they retard setting times whilst increasing the strength and water resistance of the materials. 

Ash. In ordinary wines the weights Of ash and extract are approximately in the ratio x xo. A greater proportion Of ash may be due to some treatment of the -wine, such as plastering, addition of alkaline salts to correct acidity, salt, phosphate, alum, or impure mineral substances (kaolin, Spanish clay) used as clarifying agents. 

Uses Binder, carrier, compounding agent, dispersant, stabilizer, protective colloid in polymerization textiles paper adhesives cement/plaster additive peelable caulks ... 

Plaster additives to control viscosity United States 3,544,344 1970 Sinclair Research... 

Uses Binder, carrier, compounding agent, dispersant, stabilizer, protective colloid in polymerizations for textiles, paper, cement/plaster additive, films, ceramics, molded prods., mold release useful for remoistenable adhesives, wood adhesives, envelope, label, bookbinding, padding, carton sealing applies. 

Hydrobrite 300PO dispersant, plaster Celvol 205 Dispex N100 Polyacrylamide TEGO Dispers 715 W dispersant, plaster additives Celvol 523 Celvol 540 dispersant, plaster slurries Hydropalat 7003... 

CaSO4-0-5HiO, prepared by heating gypsum at 130 "C, is used as plaster of Paris. Gypsum and anhydrite are used for H2SO4 production and gypsum is used as a soil additive and as an inert additive to pharmaceuticals and insecticides. 

The medium is the binder which provides for the adhesion of pigments. The most important types are the temper media (glue, egg, and gum), the oils, and wax. In addition, for wall painting there is the tme fresco technique, where the pigments are laid down in a fresh, wet plaster preparation layer. Several other media have been used, but much less frequendy, eg, casein temper. In modem paints, a number of synthetic resins are used for this purpose. Contemporary artist paints are often based on acryhc polymers (see Acrylic ester polymers Paints). 

P-Hemihydrate. The dehydration of gypsum, commonly referred to as calcination in the gypsum industry, is used to prepare hemihydrate, or anhydrite. Hemihydrate is generally called stucco in North America and plaster in many other continents. In North America, plaster is differentiated from hemihydrate or stucco by the inclusion of additives to control intended use properties, eg, rehydration time, density, coverage, strength, and viscosity. 

Hemihydrate. The abiUty of plaster of Paris to readily revert to the dihydrate form and harden when mixed with water is the basis for its many uses. Of equal significance is the abiUty to control the time of rehydration in the range of two minutes to over eight hours through additions of retarders, accelerators, and/or stabilizers. Other favorable properties include its fire resistance, excellent thermal and hydrometric dimensional stabiUty, good compressive strength, and neutral pH. 

As a result of the linear expansion, the reduced volume of the dihydrate, and the evaporation of excess water, the percentage of void spaces in plaster is ca 45%, in stone 15%, and in improved stone 10%. Thus, the additional amount of water required for plaster contributes to the volume but not to the strength of the hardened material (105). 

Model plasters are manufactured from select finishing plasters with special emphasis on a clean, white color. Setting-time control agents, setting-expansion control additives, fillers, and pigments may be added. 

The plaster cast forms through a chemical reaction upon the addition of water to Plaster of Paris. This reaction releases heat, warming the hardened cast. 

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