Pigments blues

Phthalocyanine blues and ultramarine blues do not have this absorption, but do not have the high-performance durability of CICP pigments. When possible, color formulations wiU try to formulate without blue additions to maintain a high IR reflectance. 

Factories in the People s Republic of China, and India produce on the whole laundry grade materials. There are only three major producers of high-grade ultramarine pigments - Holliday Pigments (United Kingdom, France), DKK (Japan), and Nubi-ola (Spain, Romania, India, Colombia). In 2000 total worldwide production of all ultramarine was ca. 25,0001 a f 

The term iron blue pigment as defined in ISO 2495 has largely replaced a great number of older names (e.g. Paris blue, Prussian blue, Berlin blue, Milori blue, Turnbull s blue, toning blue, and nonbronze blue). These names usually stood for insoluble pigments based on microcrystalUne Fe(II)Fe(III) cyano complexes many were associated with specific hues. A standardized naming system has been demanded by users and welcomed by manufacturers, and has led to a reduction in the number of varieties [3.169]. 

Iron blue [14038-43-8], C.I. Pigment Blue 27 77510 (soluble blue is C.I. Pigment Blue 27 77520), was discovered in 1704 by Diesbach in Berlin by a precipitation reaction, and can be regarded as the oldest synthetic coordination compound. Milori was the first to produce it as a pigment on an industrial scale in the early nineteenth century [3.170]. 

X-ray and infrared spectroscopy show that iron blue pigments have the formula M Fe Fe (CN)(5 XH2O [3.171]. M represents sodium, potassium or ammonium, of which potassium and ammonium ions are preferred in industrial manufacture because they produce excellent hues ammonium is the most common one. 

The presence of coordinative water is essential for stabiUzation of the crystal structure. Removal of this water, however carefully carried out, destroys the pigment properties. Many investigations helped to elucidate the structure of iron blue [3.172-3.175]. 

There is no listed threshold limit value or maximum exposure limit for the pigment. Normal practice is to consider it a nuisance dust with TLV 10 mg/m3. The pigment is not listed as a dangerous substance in the EC nor in any similar national or international classification neither is it classified as hazardous for disposal. 

The production process evolves close to 1 t of gaseous sulfur dioxide and 0.3 t of water-soluble sodium sulfoxides for every tonne of pigment produced. These must be disposed of in an environmentally acceptable manner. If the soluble salts are fully oxidized, they can be discharged safely into tidal waters. Future legislation in all producing countries may require removal of sulfur dioxide from the effluent gases before discharge to the atmosphere. 

Factories in several countries produce laundry-grade materials, including several in the People s Republic of China, India, Eastern European countries, and one in Pakistan. Neither the numbers of these units nor their outputs are accurately known. 

There are only four major producers of high-grade ultramarine pigments -Dainichi Seika (Japan), Nubiola (Spain), Prayon (Belgium) and Reckitt s Colours (France, United Kingdom) - with two smaller producers in Austria and Colombia. In 1990 total worldwide production was ca. 20000 t/a. 

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Two blue pigments can be prepared in transparent form cyanide iron blue and cobalt aluminum blue. These pigments are used in achieving a blue shade of the metal effect pigments in metallic paints. Transparent cyanide iron blue is prepared by a precipitation reaction similar to the one used for the preparation of the opaque pigment, but considerably lower concentrations of solutions are used. It is produced by Degussa (Germany), Manox (U.K), and Dainichiseika (Japan). 

In some cases, a single chemical substance can serve both as a dye and as a pigment. For example, indanthrone [81-77-6] (Pigment Blue 60) functions as a blue pigment or as a dye. As a pigment, indanthrone is a particulate, insoluble soHd dispersed directly into a vehicle, whereas as a dye it is reduced to a base-soluble hydtoquinone derivative and then reoxidized onto a soHd substrate. 

Ferric ammonium ferrocyanide—The blue pigment obtained by oxidising under acidic conditions with sodium dichromate the acid-digested precipitate resulting from mixing solutions of ferrous sulfate and sodium ferrocyanide ia the presence of ammonium sulfate. The oxidized product is filtered, washed, and dried. The pigment consists principally of ferric ammonium ferrocyanide with small amounts of ferric ferrocyanide and ferric sodium ferrocyanide. 

Cobalt ores are often found in association with copper(II) sulfide. Cobalt is a silver-gray metal and is used mainly for alloying with iron. Alnico steel, an alloy of iron, nickel, cobalt, and aluminum, is used to make permanent magnets such as those in loudspeakers. Cobalt steels are hard enough to be used as surgical steels, drill bits, and lathe tools. The color of cobalt glass is due to a blue pigment that forms when cobalt(II) oxide is heated with silica and alumina. 

Phenazines — This large class of compounds includes more than 6,000 natural and synthetic representatives. Natural phenazines are secondary metabolites of certain soil and marine microorganisms. The main phenazine producers are Pseudomonas and Streptomyces species. Pseudomonas strains produce the most simple phenazines tubermycin B (phenazine-1-carboxylic acid), chlororaphine, pyocyanin, and iodinine. Pyocyanin is a blue pigment while chlororaphine is green both are produced by Pseudomonas aeruginosa. They can be seen in infected wounds of animal and human skins. Iodinine is a purple phenazine produced by Pseudomonas aureofaciens. 

Park, J.-E. et al.. Isolation and characterization of water-soluble intermediates of blue pigments transformed from geniposide of Gardenia jasminoides, J. Agric. Food Chem., 50, 6511, 2002. 

Park, Y.S. et ah. Physical stability of the blue pigments formed from geniposide of Gardenia fruits effects of pH, temperature, and light, J. Agric. Food Chem., 49, 430, 2001. 

Three regulators were identified by genetic analysis. The main repressor, KdgR, controls the transcription of pectinase genes, the intracellular catabolic pathway and the secretion machinery. The PecS repressor controls the production of pectate lyases and cellulases, the secretion machinery and the biosynthesis of a blue pigment. PecT acts as a repressor of the production of some pectate lyases. Other proteins are involved in the regulation of pectinase s5mthesis but their role is not well characterized. 

Isolation of mutations increasing pectinase synthesis led to the characterisation of the pecS locus (67). Inactivation of pecS results in derepressed synthesis of pectinases, of the cellulase CelZ, of the secretion machinery and of an extracellular insoluble blue pigment (Figure 4). 

Formerly derived from the natural mineral lapis lazuli, ultramarine blue pigments have, for more than a century, been manufactured synthetically. The materials used in the manufacture of ultramarines are china clay (a hydrated aluminosilicate), sodium carbonate, silica, sulfur and a carbonaceous reducing material such as coal tar pitch. For the manufacture of the blue pigments, the blend of ingredients is heated to a temperature of 750 800 °C over a period of 50-100 h, and the reaction... 

Chrome green is produced by mechanically mixing chrome yellow and iron blue pigments in water. An iron blue, [Fe(NH4) (FeCN6)], is an oxidized precipitate product of the reaction between an aqueous solution of iron sulfate and ammonium sulfate with sodium hexacyanoferrate. 

The reddish metal was already known in prehistoric times. It occasionally occurs as a native metal, but mostly in conspicuous green ores, from which it is extracted relatively easily. It is convenient to work, but not very hard. Not very optimal as a tool ("Otzi the Iceman" had a copper axe with him). Only through the addition of tin is the more useful bronze obtained. Its zinc alloy is the versatile and widely used brass. Copper is one of the coinage metals. Water pipes are commonly made of copper. Its very good thermal and electrical conductivity is commonly exploited (cable ), as well as its durability (roofs, gutters), as the verdigris (basic copper carbonate) protects the metal. Cu phthalocyanines are the most beautiful blue pigments. Seems to be essential to all life as a trace element. In some molluscs, Cu replaces Fe in the heme complex. A 70-kg human contains 72 mg. 

Azurite Hydrous copper carbonate Blue 3.8 3.8 Crystalline Ornamental stone, gemstone, blue pigment, building stone, making lime... 

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