| 摘要 |
<p>PURPOSE:To obtain the title ink which suffers a less decrease in the dispersion stability of pigment with the lapse of time by adding a specified polyglycerol fatty acid ester to an ink containing a pigment, water, a water-soluble organic solvent and a water-soluble polymer and having a specified viscosity. CONSTITUTION:A polyglycerol fatty acid ester of the formula (wherein n is an integer >=4; and R is H or a 12C or higher acyl) is added to a pigment ink containing a pigment, a water-soluble organic solvent (e.g., ethylene glycol) and a water-soluble polymer (e.g., polyvinylpyrrolidone) and having an ink viscosity in the range of 50-2000cP (25 deg.C). The obtained pigment ink for ball- point pen suffers a less decrease in the dispersion stability of pigment with the lapse of time, has both the merits of a water-based pigment ink for ball- point pen and an oil-based pigment ink for ball-point pen, and can permit the use of any of resin and metallic ball pen tips.</p> |
