Powder Sulphur Colours

Product Details

Sulphur dyes are non-ionic, possess sulphur linkage, are water insoluble and produce shades that are reasonably cheap and wash and light fast. Dyes are applied in reduced and solubilised anionic state possessing affinity for cellulosics. After dyeing, oxidation is carried out to restore parent non-ionic dye structure; sulphur dye-cellulose attachment is established through physical forces with dye aggregation occurring in situ. Stored dyed cellulose is liable to be tendered in humid atmosphere due to presence of loose sulphur. Sodium sulphide, the most effective reducing/solubilising agent pollutes waste water, requiring the adoption of alternative reducing systems such as glucose, hydroxyacetone and reducing sugar. These are water insoluble dyes and have no affinity for the cellulosics as such, but solubilised when treated with a weak alkaline solution of sodium sulphide or any other reducing agent to form a leuco compound. These leuco compounds are water soluble and have affinity for the cellulosic materials such as cotton, viscose, jute and flex etc. These dyes are absorbed by the cellulosic material in the leuco form from aqueous solution and when oxidized by suitable oxidizing agents, got converted into insoluble parent dye, which is fast to normal color fastness parameters.   Shades lack tinctorial brilliance, limiting production to only deep shades like blue, black, khaki and green while brilliant red, orange and yellow are unsuccessful. BASIC PROPERTIES:-   1.: Economical dyeing with excellent tinctorial value and good build up properties. 2.: Good overall colorfastness properties such as wash fastness, light fastness, perspiration fastness etc. Moderate fastness to crocking and poor fastness to chlorines bleaching agents such as bleaching powder and sodium hypochlorite. 3.: Limited shade range to produce only dull shades and there is no true red dye in the range. 4.: These dyes can be applied by exhaust, semi continuous or continuous dyeing methods on garment, yarn, knits, fabric as well as loose stock etc. 5.: Available in powder, granules and liquid forms. 6.: Sulphur black 1 is the major black dye used worldwide for dyeing of cellulosics. 7.: The conventional dyeing process is not environment friendly due to pollution problems of sodium sulphide as well as sod/pot. Dichromates. 8.: When dyed by using non polluting reducing and oxidizing agents the process is environment friendly.   APPLICATION: Mechanism of the Sulphur Dyeing The application of the sulfur dyes involves several steps, which are described as given below,  1. Dissolving the dyestuff: 2. Reducing the dyes to form a leuco compound: 3. Dyeing with the reduced dyes: 4. Washing off the unexhausted dyestuff: 5. Oxidation back to the parent dye: 6. After treatment: 7. Dye fixing treatment: 8. Softening:9. Final treatment:10. Use of Standing Bath: