Metal‐complex Dyes for Wool and Nylon — 1930 to date

Abstract

An introduction outlining the scope and limitations of this paper is followed by a brief explanation of the essential structural features of metal‐complex dyes.The earliest metal‐complex dyes were produced directly within the fibre material by reacting a metallisable dye with a chromium compound in situ. The first chromium complex dyes prepared in substance, were the chromium complexes containing sulpho‐groups, synthesised by R Bohn of BASF, in 1912, the application of which was first made possible after the discovery by Ciba of a satisfactory dyeing process based on the use of a dyebath made strongly acid with sulphuric acid. These two classes of dye dominated the dyeing industry into the 1950s.At that time 1:2 metal‐complex dyes without sulphonic acid groups but containing nonionic substituents as solubilising groups were introduced. These complexes were applicable from neutral to weakly acid dyebaths, which minimised the damage to the fibres. These dyeings were characterised by high fastness to light and wet treatments. Later, for commercial reasons, sulphonic acid groups were again introduced into the dye molecule to increase their hydrophilic properties. These dyes also have become well established as a result of the introduction of new dyeing methods and the development of dyeing auxiliaries designed to promote level dyeing.In addition to these types of metal‐complex dyes, further metal‐complex dyes selected from the extensive patent literature of the last 50 years because of their interesting structure are described.

Textile Dyeing, 3. Dyeing of Wool and Silk

“…A lowering of the temperature to 80°C is possible in the presence of an ethoxylated fatty amine (pH 1.9-2.2). Metal complexes are formed in a molar ratio of 1:2 in the weakly acidic pH range [i.e., two chromophores are coordinated to one central atom (Cr or Co)] [27]. This atom is located between the two chromophores, which are usually arranged perpendicular to each other (Drew-Pfitzner complexes, → Metal-Complex Dyes, Section 2.2).…”

Dye Application, Manufacture of Dye Intermediates and Dyes

“…Mordant Black 11, Mordant Yellow 8, and Mordant Orange 6). When the metal complexes are formed prior to the dye application process, the resultant dyes are known as premetallized acid dyes and vary in the acid strength required in the application step [13]. The 1:1 chromium complexes (e.g., C.I.…”

Dyeing Human Hair

“…These compounds are metal complexes of anionic dyes with chromium, cobalt, or some other metal, generally in a ratio of 1:2 (metal:dye); see structure (XXXX) [55][56][57]. Some trade names are Irgalan, Cibalan, Lanasyn, Carbolan, and Isolan.…”