Continuous method of producing aqueous phthalocyanine pigment dispersions

摘要

A continuous method for producing an aqueous dispersion of phthalocyanine blue pigment is disclosed. The method involves the following two steps: (A) mixing in water a phthalocyanine crude pigment at about 10 to 50% by weight with from about 12 to 30% by weight of surfactant and (B) continuously pumping the blend of (A) through at least two shot mills in series in which the shot grinding media range in size from 0.1 to 1.5 mm. diameter and grinding the blend until the particle size of the crude is reduced to where the dispersion has suitable pigment tinctorial strength for use in inks and coatings. The aqueous dispersion of blue pigment produced by this method is especially useful in inks and coatings.