| 摘要 |
A process for the dyeing of paper material from an aqueous medium, comprising the use of at least one water-soluble dye of the formula <IMAGE> (I) wherein Py represents a pyridyl group of the formula <IMAGE> R1 represents lower alkyl, substituted lower alkyl, allyl, or benzyl, R2 represents hydrogen, halogen, methyl or ethyl, R3 represents hydrogen, methyl, ethyl or phenyl, R4 represents hydrogen, lower alkyl substituted lower alkyl, or allyl, and A(-) represents an anion. |
