| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a water-based black ink having excellent water dispersibility in water and a high level of blackness. SOLUTION: This water-based black ink is characterized by dispersing a carbon black having 30-300 m2/g nitrogen adsorption specific surface area (N2SA), 50-200 cm3/100 g DBP absorption volume, 40-160% specific tinting strength (Tint), >=3μequivalents/m2 sum total of carboxy groups and hydroxy groups in surface functional groups and 150-500 nm maximum particle diameter Dupa99% of agglomerates in an aqueous dispersion in water and regulating the pH of the dispersion to 5.0-9.0. The maximum diameter Dupa99% of the agglomerates indicates 99% cumulative frequency in a cumulative frequency distribution curve of agglomerate particle diameter prepared from the degree of frequency modulation of the scattered light by irradiating the aqueous dispersion of the carbon black with laser beams.</p> |
