STABLE WATERFUL SOLUTIONS STABLE TO STORAGE OF OPTICAL ACLARATORS CONTAINING SULFO GROUPS, PROCESS FOR ITS PREPARATION AND PROCESS FOR THE OPTICAL ACLARATION OF MATERIALS

摘要

Concentrated aqueous solutions of sulfo group-containing fluorescent brighteners, which are stable on storage, containing a stilbene fluorescent brightener substituted by sulfo groups and a lactam of the formula IMAGE in which m is 0 or an integer between 1 and 9, and their use for the fluorescent brightening of high molecular weight organic material.