Water base erasable ink composition for use in marking pens

摘要

A water base erasable ink composition for use in marking pens which comprises 0.05-20% by weight of a colorant and 1-20% by weight of an oily material which is nonvolatile at normal temperatures (25° C.) and is dispersed in water, wherein the oily material has a viscosity of 5-40 mPa.s at 20° C. and is dispersed in water in the form of emulsion, and wherein the colorant is dispersed in the water with the aid of a polyvinyl alcohol resin as a dispersing agent which has a saponification degree of 70-85 mol % and of which aqueous solution of 4% concentration has a viscosity of 2-30 mPa.s at 20° C. in a weight ratio of the resin to the colorant of 0.5 to 5 and in an amount of 1 to 10% by weight based on the ink composition.