Commercially Available Naphthol AS Pigment Lakes

2 Commercially Available Naphthol AS Pigment Lakes General 

There is no common structural principle to these pigments beyond the basic Naphthol AS pigment skeleton. Table 21 lists the commercially available Naphthol AS pigment lakes. 

a barium lake, being produced in Japan, affords a bluish red color, which may be referred to as carmine. Of medium tinctorial strength, the pigment is used primarily in plastics. 

Good dielectrical properties make it a suitable candidate for PVC cable insulations. 

One of the primary fields of application for P.R.151 is in polystyrene, although there is a slight color change at temperatures above 260°C, at which the pigment partially dissolves. It is also used to a considerable extent in ABS. Cast resins based on methylmethacrylate and unsaturated polyesters are also frequently colored with P.R.151, which is resistant to the peroxide catalysts that are used to harden the plastic. The lightfastness in these media is good it equals step 6-7 on the Blue Scale. 

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Table 21 Commercially available Naphthol AS pigment lakes.

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