Using Pigments

Coloring and Decorating. Commercial pigments that are thermally stable at the resin processing temperature maybe used. Pigments maybe dry-blended with the resin, or ETFE pellets may be blended with color concentrates, which are available ia pellet form. 

For an almost complete Hst of useful pigments, see Ref. 10. Most suppHers identify thek pigments by Cl designations and common names (Table 2). 

Commonly, various soluble synthetic dyes ( coal tar dyes ) and insoluble pigments are used. Commonly used pigments are the iron oxides. 

Colorants. This is often the determining feature of a plastic article. Two types of colorants are used pigments and dyes. Pigments are mostly inorganic... 

Lithopone, a commonly used pigment containing barium sulfate and zinc sulfide, is produced by the following reaction ... 

Because of the requirements of insolubility in water, in organic solvents and in the medium that it is being used to colour, the application processes for using pigments are quite different from those for dyes. Coloration with pigments is essentially a process of dispersion of solid particles of the pigment in a semi-solid medium. 

P.Y.154 is a useful pigment for the printing ink industry wherever high light-fastness is required. Letterpress proof prints up to 1/25 SD equal step 6-7 on the Blue Scale for lightfastness, which is at least 11/2 to 2 steps above that of similarly colored diarylide yellow pigments or representatives of the monoazo yellow pig-... 

P.Y.110 affords very reddish shades of yellow. Good fastness properties make it a widely used pigment. 

Incorporated in plasticized PVC, P.B.15, like other phthalocyanine pigments, is usually entirely fast to migration. Moreover, it provides excellent lightfastness. P.B.15 also finds use in various types of PUR foam materials as well as in rubber. Its redder and frequently cleaner shade compared to corresponding stabilized types makes it an equally useful pigment for other media. This applies especially for water-based systems. Textile printing, paper mass coloration, paper surface treatment, and paper pulp are areas of application as suitable for the use of P.B.15 as office articles, including colored pencils, blackboard chalks for schools, and water colors. 

There are various techniques of aftertreating the crude product which convert it into an industrially useful pigment. Important methods include reprecipitation from sulfuric acid, milling, and recrystallization from solvents. It is also customary to combine these methods in order to optimize the results [3]. 

Kneading or milling the crude indanthrone in the presence of finishing agents, such as polyols, or milling it with salt also affords a product which provides useful pigment properties. 

Flavanthrone, like indanthrone, must be extremely pure in order to develop useful pigment properties. Subsequent finishing converts the thus prepared material into an appropriate product for use in paints or plastics. 

In addition to 6,14-dibromopyranthrone, there are some mixed halogenated pyranthrone derivatives which exhibit equally useful pigment properties. 

For, e. g., the coloration of carpet fibers, the industry currently uses pigments which are added to the polypropylene before the spinning process (also known as solution dyeing ). The use of pigments strongly limits the end producers in the selection of colors, as only a limited variety of colored base fibers can be kept in stock. Moreover, many pigments have a negative influence on the mechanical behavior of the fibers. 

Uses. Pigment in paint, varnishes filler for paper, rubber, soap lubricating molds and machinery heat insulator... 

The current position in the dye-pigment debate is that, where light fasmess is not a problem, dyes take precedence because of brighter shade, better colour gamut and inherently more stable inks. Commercial printers prefer to use pigments as they have... 

A paradigmatic example is provided by an extensively used pigment Pmssian blue— potassium-iron(III) hexacyanoferrate(II), also called potassium-iron(III) fer-rocyanide. This is constituted by potassium-iron(III) ferrocyanide, KFe[Fe(CN)g], whose electrochemistry has been extensively studied [74-77],... 

In some cases, the deposit of lead metal also consist of irregular aggregates far from the original particles of the lead compound [126], as can be seen in Fig. 2.10 for minium (Pb304)—another widely used pigment These features can be rationalized, assuming that the electrochemical pathway represented by Eq. 2.6 can eventually be coupled by a reductive process via formation of Pb + in solution... 

Phthalocyanines with various central metals are some of the most widely used pigments and dyes and they have found industrial uses for oil desulfurization, as photoconducting agents in photocopiers, deodorants, germicides, optical computer disks and much more11,179,180. As outlined below, nowadays attention is focused on semiconductor devices, photovoltaic cells, optical and electrochemical sensing and molecular electronic materials. 

Determination Of Residual DCB In Diarylide Yellow. Diary-lide yellow is a widely used pigment derived from DCB. The purpose of this study was to determine residual DCB in a lot of the commercial pigment being used in animal feeding experiments. 

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