METHOD FOR PRODUCING PIGMENT-KNEADED PRODUCT AND AQUEOUS PIGMENT DISPERSION

• Main Authors: SATO Yoshihiro, OKADA Shinichi, HAYAKAWA Kohei, SUGO Kenji
• Format: Patent
• Language: English; French; German
• Published: 14.04.2021
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMISTRY; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; CORRECTING FLUIDS; DYES; FILLING PASTES; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; MIXING, e.g. DISSOLVING, EMULSIFYING, DISPERSING; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; POLISHES; PREPARATION OF CARBON BLACK; TRANSPORTING; TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES; USE OF MATERIALS THEREFOR; WOODSTAINS

A problem to be solved by the present invention is to provide a method for producing a pigment-kneaded product that can be used for the production of an aqueous pigment dispersion having an extremely small volume-average particle diameter of a dispersed substance, including a small number of coarse particles even in the initial stage of production, and being excellent in terms of preservation stability and that can be used for the production of ink having excellent initial discharge stability and favorable temporal discharge stability which prevent the clogging of ink discharge nozzles or the like in the initial stage of ink discharge. The present inventors solved the problem by a method for producing a pigment-kneaded product having a step [1] of supplying at least a pigment and a resin to a container provided in a kneading apparatus and a step [2] of kneading the resulting content (content (a1)) present in the container until a storage elastic modulus of content (a1) at an angular frequency of 1 rad/s, which is obtained by measurement of dynamic viscoelasticity at 25°C, reaches a range of 200 kPa to 30,000 kPa.