Something about dyes

Dye is the substance that is able to make fibers and other materials coloring. Dyes are colored substances, but color material is not necessarily a dye. Dye is able to make a certain color attached to the fibers of the material, and they are usually soluble in water, some dyes require a mordant agent to make a dye adhered on fiber. Archaeological data shows that dyeing technology has over 5,000 years of history in the Middle East and India. But that time of dye came from the flora and fauna or minerals with very little processing.

In 1856, Perkin invented the first synthetic dye purple ponytail to make the organic chemistry identified a new discipline - chemical dyes. In the 1950s, Pattee and Stephen found that dye contains Dichloro-triazine groups bonded with the hydroxyl groups of fibers in alkaline conditions. It marked dyes make fibers colored development from physics process to chemical processes, creating a synthesis application time of reactive dyes. Dyes are not only used in the dyeing and printing of textiles, but also applied to paint, plastic, leather, optical communications, food and many other sectors.

Dyes can be divided into the following categories according to application:

1. Direct dye Such dyes and fibers combined with Vanderbilt and hydrogen bonding between molecules, molecules containing sulfonic acid groups, carboxyl and soluble in water. It exsit in water as anionic form, and can make fiber dyed directly.

2. Acid dyes In acidic medium, the dyes molecules containing sulfonic acid groups, carboxyl and amino of protein fibers bonding by ionic. It mainly for the protein fibers (wool, silk, leather) staining.

3. Disperse dyes Small soluble and using dispersants to make hydrophobic fibers (polyester, nylon, etc) staining.

4. VAT dyes VAT dyes are divided into insoluble and soluble two kinds. Insoluble dye can vat into soluble in alkaline solution, oxidation to make the dyeing resumed its insoluble in fibers, then the fibers coloring. Soluble do not need the restore step. This dye is mainly used for dyeing and printing of cellulose fibers.

5. Reactive dyes Dye molecules exist groups that can have chemical reactions with of hydroxyl and amino of fiber molecules. Mainly used for dyeing of cotton, linen, synthetic fiber, as well as the colouring of the protein fibers.

6. Cationic dyes Used for the dyeing of acrylic fibers. It often incorporated into the basic dye class.

7. Azoic dyes It is a insoluble azo dye. It is dyed in freezing conditions（0-5℃）. Click here to get more!