Israfil Alam Rana, Assistant Manager (R&D)
Sister Denim Composite Limited – Thermax Group
Denim is a strong, durable fabric, once upon a time denim was worn only as working wear. But now it is widely used as a fashion wear. The most common denim is indigo dyed, in which the warp thread is dyed, while the weft thread is left undyed. But giving the most attractive looking to denim wear, different types of printing are done on denim fabric.
Reactive printing on denim:
Reactive print like reactive dye is usually of better crocking standards and more colorfast than pigment print. However, we should know reactive print can be stand chlorine bleach, but pigment print or pigment dye can. In the process of reactive print, you can use the same rotary or screen to print, but you need additional equipment to finish the dye steaming and washing. It is important to know, in reactive print as well as reactive dye, if the process is not done correctly with the right amount of color fixing agent, properly steamed and washed; there will still be problems of color fastness and crocking, or even staining. Fabrics printed with reactive dye are completely soft as the steaming and washing process takes away most of the starch from the fabric. This is another advantage of reactive print.
Discharge printing on denim:
This printing method is generally used to obtain designs with tiny details, sharp and well defined edges on colored backgrounds, patterns with low coverage ratio on colored backgrounds, and to avoid pattern matching problems on endless design patterns with colored backgrounds. The results obtained with this printing method could be hardly reproducible with direct printing since it would be very difficult to obtain wide backgrounds, smooth and well penetrated, with sharp edges without seam defects.A problem for this printing method is represented by the need to choose perfectly destroyable dyes for backgrounds, which cannot be affected by the discharging agent used as brightener. The selection restricts the number of applicable dyes and above all, for some color classes, very few dyes grant a good fastness to light and moisture, but excellent color effects.
Beside these techniques, there are lot of modern technique arrives with latest fashion. Denim is not just a blue shade jean today. It’s going far from its old nature.