| 摘要 |
<p>PURPOSE: To prepare a black ink which can be written with a marking pen on a white board and can be wiped out, by adding a specific carbon black, a polymer soluble in a lower alcohol and a releasing agent to a medium mainly comprising a lower alcoholic solvent. CONSTITUTION: This composition is prepared by admixing a carbon black having more than 85% toluene-coloring transmission rate and less than 0.5wt.% ash content, a polymer soluble in lower alcohol and a releasing agent to a medium which mainly comprises a lower alcohol such as methanol, ethanol, n-propanol or isopropanol, additionally, a glycerol solvent and sucrose ester as a whitening preventive and a humectant, and shows reduced change in ink viscosity and particle sizes of carbon black in the ink even under elevated temperature or after a longed term storage.</p> |
