| abstract |
(57) [Summary] [Problem] To prevent the pigment from settling in the core, even if the pigment settles in the core after a lapse of time, shading may occur in the handwriting (color separation). In addition, the ink composition does not cause clogging at the pen tip made of felt tip, plastic molded product, etc., and does not cause blurring of writing. Provided is an aqueous pigment ink composition for use. SOLUTION: As a thickening agent, at least one kind of thixotropic agent selected from polyacrylic acid, an alkali metal salt of polyacrylic acid, an organic amine salt of polyacrylic acid and a polyol is used. The viscosity at 0.01 Pa is 45 mPa · s or more, and the stress is 10 Pa Is 12 mPa · s or less. |