Metal complex azo dyes of aromatic series - for dyeing of leather, skins and synthetic fibres, e.g. polyamide(s) and polyvinyl alcohol

摘要

New metal complex azo dyes of formula (I) in which Ar is (Ia) or (Ib); R and R' are -COO- or pref. -O-; R" is SO3H (pref.), COOH or SO2NH2; x is 2-5; Me is a complex-forming metal, pref. Cu or Fe. (I) are used in dyeing of protein fibres, esp. leather and skins, and synthetic fibres, e.g. polyamides and polyvinyl alcohol. In addn. to dyeing leather, the cpds. tan and fill the material and improve its hygienic properties. Prepn. is simple, from readily available materials. A range of fast shades can be obtained, thermostability of the collagen is improved, and dye bath temp. can be reduced.