Dying with sulphur dyes

Definition:       The sulphur dye contains “-s-S-” linkage in its chemical structure and here it is so called.

Chemistry of dyeing with sulphur dyes:

          Sulphur dyes are water insoluble and need reduction for solubilization. After solubilization it is applied in the fibers and oxidation is necessary for making the dyes insoluble again in the fibers. The dye is similar to vat dye during application.

                  

Properties of sulphur dyes:

(1)       Sulphur dyes are complex hetero cyclic molecules containing sulphur linkage.

(2)       Dyes are excessively amorphous a few show crystalline.

(3)       Water insoluble and chemical composition varies among the producers.

(4)       Applied specially for black shades in the cellulosic fibers.

(5)       Fastness properties average to good.

(6)       Cheap and easy to apply.

(7)       Oxidation is necessary for final shade development

Azoic Color | Properties of azoic color

Definition: Azoic dyes are not ‘ready – made’ dyes but are produced through an in-site process which creates the colored material directly on the fabric by a coupling reaction between napthol/ coupling component and diazo component.

Properties:

(1)  Water insoluble dyes.

(2)  There ere two component of dye molecule.

(3)  Color is developed by a coupling reaction.

(4)  Applied in alkaline condition.

(5)  Very suitable for cellulosic fibers.

(6)  It is applied for bright colors.

(7)  Fastness properties good.

(8)  Comparatively cheap in price.