Process for the production of monoazo lake pigment coated with water-insoluble rosin and improved in lipophilic nature and water resistance

摘要

A process for the production of a monoazo lake coated with a water-insoluble metal salt of rosin, which comprises the steps of: (a) adjusting a mixed solution containing a monoazo dye having a water-soluble group and an alkali metal or ammonium salt of rosin to pH of 8 to 12, and adding an stoichiometeric amount of a metal salt of at least one metal for insolubilizing rosin selected from the group consisting of zinc, aluminum, copper and manganese to form a water-insoluble rosin metal salt, and (b) adjusting the resultant mixture containing the water-insoluble rosin metal salt to pH of 9 to 12 and adding a metal salt of at least one metal for forming a lake of a monoazo dye selected from the group consisting of calcium, barium and strontium to form a monoazo lake.