Improved marking fluid

摘要

A marking ink contains hydroxypyrene trisulfonic acid or a derivative, together with a sugar or sugar alcohol which is palatinose, trehalose, trehalulose, maltitol, 6-O-alpha-D-glucopyranosyl-D-sorbitol (1,6-GPS) or 1-O-alpha-D- glucopyranosyl-D-mannitol (1,1-GPM). An Independent claim is also included for production of the marking ink by mixing a sugar or sugar alcohol with an aqueous composition containing hydroxypyrene trisulfonic acid or a derivative and optionally also a buffer, a preservative, a moisture retention agent and/or other additives.