METHOD FOR MANUFACTURING A WATER-BASED INK FOR INKJET PRINTING AND A WATER-BASED PIGMENT DISPERSION LIQUID

摘要

An object is to provide a highly efficient method for producing a water-based ink for ink jet recording with which the number of coarse particles in a water-based pigment dispersion liquid is significantly reduced, dispersed particles are made finer, the dispersion stability is improved, the storage stability is improved, and high discharge stability is achieved when a water-based ink for ink jet recording is produced. To achieve the object, provided is a method for producing a water-based pigment dispersion liquid, the method including a kneading step of kneading a mixture containing a quinacridone type pigment (a), a styrene-acrylic acid type copolymer (c), a basic compound (d), and a polyoxyalkylene glycol or its derivative (e) to prepare a pigment dispersion that is solid at room temperature and a mixing step of mixing an aqueous medium and the pigment dispersion to decrease the viscosity and liquefy the pigment dispersion.