23 ноября, 2015 
Pokraskin Among the different chemical classes, this group of extenders has the most variety, with a wide range of properties and crystal forms. Following silicate extenders are important for the coating industry:
Magnesium silicate (talc, asbestine, French chalk); (3MgO4SiO 2H2O)
This category covers a number of minerals with varying chemical composition based on magnesia and silica. They frequently have calcium and aluminum as impurities. Depending upon source, they are either plate-like or acicular particles. Asbestine, an exception, is fibrous. Some of the beneficial properties of talc for use in coatings include good brightness, chemical inertness, good suspension properties, ability to provide mechanical reinforcement to paint films, brushability and good enamel hold-out. Talc is a hydrophobic and soft mineral that promotes sandability of fillers and primers as well as providing good intercoat adhesion. Talc is also used to impart a flatting effect and is suitable for semi-gloss and satin industrial enamels. One of the limitations of talc is that when used in exterior conditions, it chalks readily.
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