Azo condensation pigments

The solution to this difficulty, discovered by Schmid of Ciba in the early 1950s, is to reverse the order of the two steps. The diazotised amine is first coupled with BON acid and then two moles of this intermediate are condensed with one mole of benzidine in the form of its hydrochloride. The condensation is carried out in a high-boiling solvent such as nitrobenzene, when yields of 95% can be attained. These pigments have been called azo condensation pigments in view of their method of synthesis. 

The small range of azo condensation pigments has become established only because they combine outstanding fastness to light, heat, solvents and chemicals, finding acceptance for use in paints, printing inks and the coloration of plastics and some synthetic fibres. 

There is a large number of organic pigments. They are carbon black,s, phthalo-cyanines, quinacridones, perylenes, basic and acid colorants, anthraquinones, diazines, isoindolidones, azo and azo condensation pigments [2,10]. 

Aw Condensation Pigments. A further improvement in heat stability of azo pigments was achieved by the condensation disazo pigments due to an enlarged molecular framework and higher molecular weight. Formally they are composed of two monoazo or more accurately two monohydrazone units, which are attached to each other by an aromatic dicarbonamide bridge. 

Disazo Condensation Yellows and Reds. Disazo condensation pigments provide important performance improvements over traditional azo types. Pigments in this family range from green- to red-shade yellows and from yellow- to blue-shade reds to violets and even a red-shade brown. The condensation chemistry derives the... 

Figure 9 summarizes the predicted values for UVA 1 loaded at 10% into concentrates containing carbon black, CPC blue, bismuth vanadate, azo condensation and quinacridone pigments. The NIR measured values range from 6.7% to 35% versus the expected 10%. 

There are two main types of high performance azo pigments. Disazo condensation pigments are a range of durable, if rather expensive, yellow, red, violet and brown products with complex high molecular... 

Because of their high opacity, THI pigments do not provide any advantage over azo condensation or perylene pigments for fiber applications. 

Flexible PVC, calendered, extruded or injection moulded Heat stability up to 200°C Non migratory, non chalking light stability depending on application Cadmium pigments, red and yellow toners Azo-condensation Polycyclics Lead pigments Phthalocyanines Bis-arylamides Isoindolinones Iron oxide Dioxazin Special monoazos... 

LDPE Heat stability normally up to 240°C Moderate light stability for many applications Easy dispersion important Red and yellow toners Selected Bis-aryiamides Isoindolinone Azo condensation Phthalocyanine Green Phthalocyanine Blue Cadmium pigments Iron oxides Lead pigments Ultramarine Blue Vat pigments Special monoazos... 

Crystal PS Good light stability Processing temperatures up to 240°C Red and yellow toners Polycyclics Azo condensation Isoindolinone Metal complex Phthalocyanine Blue Phthalocyanine Green Selected dyes Ultramarine Blue Cadmium pigments Lead pigments Special monoazos... 

Impact PS Good light stability. Must withstand temperatures up to 280X Yellow and red toners Polycyclics Isoindolinone Selected Bis-arylamides Phthalocyanine Blue Phthalocyanine Green Metal complex Selected dyes Cadmium pigments Ultramarine Blue Azo condensation Special monoazos... 

ABS Good light stability. Temperature resistance of up to 260°C is required but many pigments which will withstand this temperature in polyolefins fall down in this polymer Azo condensation Selected polycyclics Phthalocyanine Blue Phthalocyanine Green Cadmium pigments ... 

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