Organic pigments blues

Phthalocyanine pigments account for approximately 23% of the total worldwide organic pigment consumption of 225,000 tons. Approximately 20,000 t are used in printing inks, 10,000 t in paints, 9,000 t in plastics, 3,000 t in textiles, 7,000 t in dyes, and 2,000 t in specialty uses. Table 1 shows the worldwide distribution of cmde phthalocyanine capacity. The production history of phthalocyanine in the United States from 1980 to 1990 is given in Table 2 (161). The 1990 prices of phthalocyanine blue and green pigments were ca 11—22/kg and 21—27/kg, respectively. 

Some anthraquinone dyes are employed as organic pigments (see Pigments, organic). Examples appear in Figure 1. Indanthrone blue (6) is an important automotive paint pigment as is Cl Pigment Red 177 (7), a bisanthraquinonyl. 

Fig. 1. Anthraquinone dyes used as organic pigments (4) = dibromoan than throne [4378-61-4] (Cl Pigment Red 168 Cl Vat Orange 3 Cl 5930G) (5) = an anthrapyrimidine [4216-01 -7] (Cl Pigment YeUow 108 Cl Vat YeUow 20 Cl 68420)-, (6) = indanthrone blue [81-77-6] (Cl Pigment Blue 60 Cl Vat Blue 4 ...

The molecular basis of most of these processes is not yet clear. Most of what we know concerns the absorption of quanta by the photoreceptor pigments, while stimulus transformation and signal transmission have as yet been investigated only in part and in a very few organisms. In blue-green algae, not even the movement mechanism is clear, so that any model of the motor response is highly speculative. 

It has often been observed that the coloristic properties of an organic pigment are a function not only of the size of particles but also of their shape. This is due to the anisotropy of the optical properties in different crystallographic directions within the crystal forms of a pigment. In 1974 [5, 6], it was demonstrated that of the equally sized but differently shaped particles of beta copper phthalocyanine blue, the almost completely cubic, i.e., more or less isometric form produces greenish blue shades, while acicular forms are responsible for reddish blue hues. The optical behavior of ordered pigment particles in systems has been reported in the literature [7, 8]. 

P.V.50, produced in Japan, is only of limited regional importance, since it fails to satisfy the increasingly stringent application requirements for organic pigments. Its fastness to light, for instance, is particularly poor 1/3 SD and 1/1 SD letterpress proof prints equal only step 2 on the Blue Scale. Compared to P.V.23, Dioxazine... 

At present, Phthalocyanine Blue and Phthalocyanine Green are among the most important organic pigments in the market and are sold in large volume. 

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