PURPOSE: To provide the title composition having excellent weatherability, water resistance, dispersion stability and storage stability, which comprises a pigment, a specific dispersant and an aq. medium containing a lowly volatile or nonvolatile hydrophilic org. solvent.
CONSTITUTION: An aq. medium prepd. by dissolving 5W200pts.wt. lowly volatile or nonvolatile hydrophilic org. solvent (e.g.: ethylene glycol) in 100pts.wt. water is incorporated with 3W30wt% org. or inorg. pigment and 3W300wt% dispersant (e.g.: styrene/ethyl acrylate/N,N-dimethylaminoethyl methacrylate copolymer), which is 1,000W100,000 in MW and has 10W93wt% lipophilic portion, 2W50wt% cationic portion and a hydrophilic portion, and optionally a humectant, an anticorrosive agent, an antiseptic, etc. They are mixed and ground with a dispergator to obtain an aqueous pigment ink composition for writing and recording having a viscosity of 1W20cps.
NAKAJIMA KEIJI
NAKAMURA MICHIEI
KANO KAZUO
SHINODA TAKAMITSU
