Benzimidazolone Pigments shades

A few years ago the pigment was withdrawn from the market. P.R.212 was rarely sold outside Japan. It produces considerably bluish shades of red, which might be considered pink. Compared to the similarly colored quinacridone pigment P.R.122, P.R.212 is duller, weaker, and less fast. 1/3 SD letterpress proof prints, for instance, equal step 2-3 on the Blue Scale for lightfastness while prints containing P.R.122 equal step 6-7. P.R.212 is also less lightfast than the somewhat more bluish and duller benzimidazolone pigment P.V.32, a coloristically related maroon the difference is 2 to 3 steps on the Blue Scale. 

Red benzimidazolone pigments, which cover the entire range of shades in the red and brown part of the spectrum, are based on the following general structure ... 

This disazo condensation pigment, is a recent product. It affords very yellowish shades of brown, covering the range of the displaced benzimidazolone pigment P.Br.32. In terms of fastness and application properties, P.Br.41 largely resembles other representatives of its class. 

While the acetoacetyl derivative 1 provides greenish yellow to orange products, the naphthoylamino compound 2 affords colorants having medium red to carmine, maroon, bordeaux or brown shades. Figure 10-2 summarizes the Colour Index data, shades and structural formulae of commercial available benzimidazolone pigments. 

F ure 10-2a Colour Index data, shades and structural formulae of commercially available benzimidazolone pigments (yellow and orange). 

Benzimidazolone-dioxazine pigments identified for commercialization thus far are red-violet to reddish-blue in shade. They are characterized by an exceptionally high tinting strength, and their heat stability and resistance to aggressive solvents and plasticizers is much superior to that of carbazole dioxazine pigments. 

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