| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject ink satisfying a cap off resistant performance and also capable of writing with maintaining a clear handwriting not having a penetration to the back of a paper by containing a coloring agent, a water soluble organic solvent containing a specific ratio of water and urea and a polysaccharide reducing a shearing viscosity. SOLUTION: This aqueous ink for a ball point pen contains (A) a coloring material, (B) a water soluble organic solvent containing 30-50wt.% water and 10-30wt.% urea in the solvent and (C) a polysaccharide reducing a shearing viscosity (preferably a succinoglycan). The ink preferably shows viscosities in EMD type rotaviscometer at 20 deg.C, 25-100mPa.s at 100r.p.m, 150-300mPa.s at 10r.p.m and 1,200-1,800mPa.s at 1r.p.m. And it is preferable to add a phosphoric acid ester-based lubricant to the ink for reasons such as for improving the lubricating property of the ink, etc. |
