Metal complex dyes which are also known as premetallized dyes show a high affinity for protein fibers. In general, it has been found that metal complex dyes are chromium or cobalt complexes. Among popular metal complex dyes, a variety known as 1: 2 metal complex dyes finds application for dyeing polyamide fibers. To dye wool, complex metal dyes are the most favored.
Metal complex dye generally cannot be said to belong to a particular dye class of application. In fact, metal complex dyes belong to numerous kinds of dye application. For example, they are in the middle of the direct dyes, acids and reagents. When applied in dyeing processes, metal complex dyes are used under pH conditions that are regulated by the type of user and the type of fiber (wool, polyamide, etc.). The pH levels for wool typically vary from:
• Very acidic (with a range of 1.8 to 4 for metal complex dyes 1: 1)
• Moderately acid neutral (ranging from 4 to 7 for metal complex dyes 1: 2)
Chemically speaking, metal complex dyes can be classified into two classes. 1: 1 metal complexes, where, a dye molecule coordinates with a single metal atom. In metal complexes 1: 2, a metal atom is coordinated with double dye molecules. The dye molecules are typically a monoazoose structure which may contain additional groups such as hydroxyl, carboxyl or amino groups. They can form strong coordination complexes with transition metal ions, such as nickel, chromium, cobalt and copper. A point to note here is that phthalocyanine dyes are not classified as metal complex dyes.
Characteristics of metal complex dyes
Below are some Characteristics metal complex dyes
• Excellent light fastness.
• Average resistance to washing.
• It shows very good dyeing and penetration characteristics.
• Can cover irregularities in substrates.
• Used at high level industry
Metal Complex Dyes is used for a variety of applications such as wood stains, cue finishing. These types of dyes are great in demand in industrial area.