Direct dyes are disclosed, which have the structure:
wherein R, R₁, R₂ and R₃ are the same or different and are hydrogen, C₁ to C₄ alkyl or C₁ to C₄ hydroxyalkyl having from 1 to 2 hydroxy groups, with the proviso that R is not hydrogen.
已公开的
直接染料具有以下结构:
其中 R、R₁、R₂ 和 R₃ 可以相同或不同,并且是氢、C₁ 至 C₄ 烷基或具有 1 至 2 个羟基的 C₁ 至 C₄ 羟烷基,但 R 不能是氢。