Vat dyes are different from reactive dyes, disperse dyes, basic dyes, acid dyes, or azoic color but their application process is near similar to sulphur dyes. Vat dyes are used for coloring cellulosic fiber especially cotton fiber. It is widely used for running the dyeing process of cotton yarns which is used for producing jeans or denim products.
Application Methods of Vat Dye:
The word vat comes from the vessel; vat dyes can be applied in a vat for coloration textile products. Vat dyes are natural coloring materials that are solubilized in a vat by the fermentation process called vatting. Vat dyes are insoluble in water but it becomes insoluble by the vatting process. The process of converting insoluble vat dyes into soluble forms is known as vatting.
Properties of Vat Dye:
Vat dyes have lots of properties that are required to remember before and during the dyeing process. The following are the main properties of vat dyes.
- Vat dyes are natural coloring dyes.
- Vat dyes are insoluble in water.
- Vatting process is needed for making the insoluble vat dyes into soluble form.
- Final color is developed by the oxidation process.
- Vatting is done in alkaline condition.
- Fastness properties of the dyes are excellent but its rubbing properties are not so good.
- Sometimes, it causes different types of skin disease.
- Vat dyes are mainly used for coloring cellulosic fibers.
- Stability of the color in the fiber is excellent.
- Wide range of color can be achieved by these dyes.
- Application of vat dyes is limited in practical life.
- Vat dyes are expensive in price.
So, it’s very interesting that most of the denim product is colored by vat dyes.