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Sulphur Dye
Sulphur dyes are one of the most commonly used dyes for producing bright black and brown shades on cellulosic fiber products. The chemistry of sulphur dye dyeing is similar to that of vat dye dyeing. In both cases, the final colour is developed by the oxidation process. Although, reactive dyes, azoic colour are available, sulphur dyes are preferable for black shade production.
Sulfur dyes are so-called because sulphur dyes contain di-sulphide (S-S) linkage in their chemical structure. The sulphur dyes dyeing process is carried out in alkaline conditions. The sulphur dyes are used for both dyeing and printing.
Properties of Sulphur Dyes
The following are the properties of sulphur dyes:
- Sulphur dye is a water-insoluble dye.
- It needs solubilization for application (with a reducing agent).
- Oxidation is needed for final color development.
- Sulphur dye is applied in alkaline conditions.
- Electrolyte can be added to the dye to enhance the exhaustion of dyes.
- Fastness properties are average.
- Best suitable for producing black and brown shades on the textile materials.
- It is mainly applied to cotton, viscose, and staple fibers.
- Its exhaustion properties are good.
- Most of the time, dyeing is carried out at 80–95 degrees Celsius.
- Sulphur dye is comparatively cheap.
Types of Sulphur dyes
There are many ways to classify sulphur dyes but thdyes,llowing types are based on solubility. They are-
- Conventional or Water insoluble dyes
- Solubilised Sulphur dyes.
- Leuco Sulphur dyes (Partially soluble)
Uses of Sulphur Dye
There is some application field of sulphur dyes uses. The following are the uses of sulphur dyes. They are-
- Firstly it use to dye cotton fabric such as lining boot.
- Secondly, sulphur dye use to dye Umbrella cloth with Sulphur black.
- Lastly, it use to dye rubber materials when after treatment is essential with CuSO4.
Limitation of Sulphur Dye Uses
Although sulphur dyes have a lot of advantage it has some disadvantage like-
- Bronziness of shade: For this defect some white spot can be appear in the fabric.
- Sulphur black tendency: This have sulphur black tendency.
So, when you will choose your dyes; check out the properties which should have dyes.
