Tintenzusammensetzung für Schreibtafeln

摘要

A writing board ink composition containing a medium of, or based on, a lower alcohol solvent, wherein a diketopyrrolopyrrole pigment represented by the following formula [I] having a median Stokes diameter of not more than 0.2 mu m, an alcohol-soluble polymer, a scraping agent and a surfactant are contained in the medium. wherein R<1> and R<2> independently represent an unsubstituted or non-water-solubilizing substituent substituted phenyl group or naphthyl group; R<3> and R<4> independently represent hydrogen or a non-water-solubilizing substituent. The writing board ink composition of the present invention remains stable for a long time while in pens even when the resin content is such that unclear writing and scrapability reduction can be avoided, since the pigment of ultrafine particle size is fast to lower alcohol solvents.