Pigment Grades Discussion of Individual Pigments

Isoindoline pigments are primarily marketed in the form of powders, but are also available as predispersed pigments (Table 14.2). 

The main applications for P.Y. 139 are aU types of paints incduding automotive finishes, plastics like polyolefin fibers and PVC and packaging inks. P.Y. 185 is mainly used for the coloration of plastics and in packaging inks. 

185 (D 1155) has fine partides very similar to those of L 1820, characteristic of a pigment with high transparency. 

The hydrodynamic diameters of the three P.Y. 139 grades determined by quasielastic light scattering (Microtac UPA 150) for L 1820, L 1970 and L 2140 HD are 145 nm, 243 nm and 344 nm, and agree well with the electron micrographs. Whereas L 1820 has a significant share of particles below 100 nm this proportion 

Obviously P.Y. 185 only absorbs violet and blue light. The reflectance edge in white reduction hes in the 500 nm region. Therefore it looks a very greenish yeUow. 

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