The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 07, 1994
Filed:
Mar. 29, 1993
Orient Chemical Industries, Ltd., Osaka, JP;
Abstract
A writing board ink composition comprises a medium formed of a lower alcohol solvent which contains an alcohol-soluble polymer, a scraping (erasing) agent, a surfactant and a diketopyrrolopyrrole pigment having a median Stokes diameter (ultrafine particle size) of not more than 0.2 .mu.m and represented by the following formula ##STR1## R.sup.1 and R.sup.2 independently represent an unsubstituted phenyl or naphthyl group of a non-water-solubilizing substituent substituted phenyl or naphthyl group, and R.sup.3 and R.sup.4 independently represent hydrogen or a non-water-solubilizing substituent. The writing board ink composition remains stable for a long time while in pens even when the resin content (alcohol-soluble polymer) is such that unclear writing and scrapability reduction (loss of scrapability or erasability) can be avoided, since the pigment of ultrafine particle size is fast to lower alcohol solvents.