| 摘要 |
PURPOSE:To provide an aqueous black ink having good solubility and less viscosity change with time and suitable as writing tools or recorder by using a direct dye of C.I. Direct Black 19 type having the measured value of 1.0 or less peak ratio. CONSTITUTION:Liquid chromatography is used to measure the peak ratio of a C.I. Direct Black 19 type direct dye which is excellent in water resistance, solubility, and color tone, etc. The dye having the ratio of less than 1.0 is used as coloring material to prepare the object aqueous black ink. |
