METHOD FOR PRODUCING PRINTING INK

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a printing ink by which aggregation of a prepigment is moderated and a resin for the printing ink is not used at all or the amount thereof used is reduced to eliminate various adverse effects of using a large amount of the resin with the result that the printing ink of excellent quality can be produced at a low production cost in the rationalized method for directly producing the printing ink by using the prepigment of copper phthalocyanine without passing through the form of a pigment. SOLUTION: This method is to directly produce the printing ink comprising at least the copper phthalocyanine and a resin by using the prepigment of the copper phthalocyanine without passing through the form of the pigment. In the method, a composition prepared by dry pulverizing crude copper phthalocyanine with a water-soluble inorganic salt or the water-soluble inorganic salt and an extender pigment and/or a resin for the printing ink and then removing the water-soluble inorganic salt is used as the prepigment.