| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a paper-coloring dye which imparts a darkish yellow color by forming a disazostilbene dye of which each terminal benzene ring is substd. at the positions ortho and meta to an azo group. SOLUTION: This dye is a yellow disazo dye represented by formula I and is obtd. by coupling a diazonium salt of flavonic acid represented by formula II to p-cresol at the o-position to a hydroxy group in an aq. medium in the presence of an alkali metal hydroxide (e.g. potassium hydroxide). When an ammonium salt is necessary, an amine or a quaternary ammonium hydroxide is used as a base. This dye can impart a color to various substrates, and can dye or print paper, paperboard, cardboard, and other cellulosic materials. In formula I, M is a hydrogen ion, an alkali metal ion, or RaRbRcRdN (wherein Ra, Rb, Re, and Rd are each H, a 1-6C alkyl, or 1-6C hydroxyalkyl).</p> |
