Some Types of Pigments

Using clay some pigments are formed and they are differentiated according to their physieal and ehemical properties and uses. These are highlighted below. 

Kaolin elay acts as ingredients for forming ultramarine blue pigments, which has dark blue eolom. Best quality ultramarine blue is used in all types of laundry while teehnieal and industrial grades for applications in coating, cosmetic, ink and plastic pigments. 

Calcined kaolin elay acts as ingredients, used in formation of washing powder and liquid blue. It is eomposed of Fe203, AI2O3, Ti02 and moisture content. Whiteness and fine partieles are main two characteristic features of it. Percentage of physical property and chemieal eomposition are listed in Table 12.6. 

Main ingredients of formation of this type of pigments are kaolin clay. It is the best pigment, extender and filler in water-based coating. It is used in paper formation. 

AI2O3 content Moisture content Ti02 content K2O content Whiteness 

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This product is employed in the preparation of antiperspirants and some types of pigments. 

Several new types of pigments have been introduced commercially which are based on polymers that do not contain formaldehyde. These pigments have some different characteristics but have the advantage of not giving off formaldehyde. Most of the primary manufacturers provide these types of pigments and more are being developed. 

The energy required to initiate an explosion and the maximum explosive pressure developed by a number of polyester—epoxy powder coatings has been studied in some detail (89). The variables studied included composition, level and type of pigmentation, particle size, and concentration in air. The lowest MEG for unfilled and unpigmented powders was 33—35 g/m. ... 

Some types of paints and pigments that are used as facial make-up or hair coloring contain lead. Cosmetics that contain lead include surma and kohl, which are popular in certain Asian countries. Read the labels on hair coloring products, and keep hair dyes that contain lead acetate away from children. Do not allow children to touch hair that has been colored with lead-containing dyes or any surfaces that have come into contact with these dyes because lead compounds can rub off onto their hands and be transferred to their mouths. 

The shortage of tungsten and molybdenum during the 1930s in Germany necessitated the use of copper ferrocyanide as anion. Some of these salts have maintained their commercial position to the present time. Besides, silicomolybdates are also used to produce this type of pigments. 

Other fine materials which tend to inhibit air entrainment include pigments, particularly carbon black. This is of concern to the ready-mixed operator supplying integrally colored concrete for exterior exposure [6]. Accelerating admixtures which are used to reduce down time and in cold weather concreting can be used successfully in air-entrained concrete, but should be added separately and in solution form to the mix. Direct contact of these admixtures with some types of air-entraining agents mixed in the same water phase may adversely affect both admixtures. 

A relatively good quality premix is required for this mill, but all types of pigments can be used. It is difficult to clean because the paste can dry on the screen and the screen can become clogged with media. These mills disperse by shearing and by some impingement. 

Household Paint Some types of paint are colloids composed of pigment particles dispersed in oil. Based on what you know about colloids, recommend an appropriate location for storing cans of leftover household paint. Justify your recommendation. 

Volatile paint components include organic solvents, water, and coalescing agents. Nonvolatile components include binders, resins, plasticizers, paint additives, dyes, pigments, and extenders. In some types of binder, chemical hardening can lead to condensation products such as water, alcohols, and aldehydes or their acetals, which are released into the atmosphere, thus being regarded as volatile components. 

Most resins that are processed require some type of fillers and/or reinforcements in order to function. Typical fillers and reinforcements are listed in Table 6-1, which shows the properties they influence. (See Chapter 7 for details on reinforced plastics.) Basically fillers and pigments are added in molding resins to reduce shrinkage, minimize crazing, lower the material cost, impart color or opacity, improve the surface finish, and so on. The most commonly used fillers are calcium carbonates, diatomaceous earths, and clays. The excessive use of fillers should be avoided, as the fluidity of the resin can be reduced to the point where it is difficult to process. 

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