| 摘要 |
PROBLEM TO BE SOLVED: To provide an ink for a ball point pen, exhibiting a light write-feeling, a short faint streak on start-writing and less dripping without sacrificing a light fastness and drip suppression. SOLUTION: This ink for the ball point pen contains >=2.5% polyvinylpyrrolidone having a high degree of polymerization of >=250,000 molecular weight, and has <=2 Pa.sec viscosity at 25 deg.C, preferably between 0.5 to 1.5 Pa.sec. Since the polyvinylpyrrolidone having a high degree of polymerization imparts a viscosity to the ink, it is difficult to produce the ink having a low viscosity. The ink having the low viscosity is realized by reducing the total solid portion of the ink (at 25 deg.C, those of not being a liquid or gas in the ink in their raw material stage) as less as possible and using a low viscosity solvent in a large amount. |
