Sulfuric Acid → Alpha.-Copper phthalocyanine

Participants

Reaction Conditions

Reaction Steps

A crude copper phthalocyanine (purity 95%) was dry-milled with an attriter for 40 minutes to give a dry-milled product having an α-crystal content of 47%. Then, 100 parts of the dry-milled product, 500 parts of sodium chloride and 25 parts of diethylene glycol were charged into a double arm kneader having a volume of 1,000 parts, and kneaded (wet-milled) at 100° to 110° C. for 3 hours while additional diethylene glycol was added to maintain a dense mass (dough). The total amount of the diethylene glycol was 80 parts. After the wet-milling, the mixture was taken into 1,300 parts of a 1% sulfuric acid aqueous solution at 70° C., stirred for 1 hour while maintaining the temperature of 70° C., and filtered. The resultant solid was washed with water and dried to give 93 of a β-copper phthalocyanine pigment. The copper phthalocyanine pigment had a particle size of 0.02 to 0.06 μm and an aspect ratio of 1.2 to 2.5.

Provenance & Evidence