Before introducing reactive dye-Sub printing, let’s have an overall understanding of dye.

Dye is a certain material to make fiber and other materials coloring. It contains natural and synthetic dyes. Dyes are colored substances. But the material with the color is not necessarily a dye. Dyes are usually dissolved in water. Archaeological data show that dyeing technology has been more than five thousand years of history in India and the Middle East. At that time the dye was taken from the animals and plants or minerals with little treatment.

As for dye-sub printing, there are strict requirements to dye.

The small directness, low affinity, and good diffusion
As it will dry immediately after printing, there will be no problem of balance like textile dyeing. Therefore, the dye-sub printing with small directness, low affinity, and good diffusion can be used directly. If use reactive dyes with a large directness, the reaction opportunities of active groups and fiber will increase, but the hydrolysis dyes are not easy to wash from textiles.

Good color paste stability 
Reactive dyes have low reactiveness at low temperature to adjust pulp and printing easily. With less dye hydrolysis, the dye can form covalent bonds with the fiber after printing at high temperature under the effect of alkali agent. Low-temperature X-type reactive dyes are generally not suitable for printing, while the medium temperature KN type, high-temperature K-type, Levafix P and Drimar ene Z are more suitable for printing.

No bond breaking phenomenon
The fabrics after dye-sub printing should avoid bond breaking phenomenon due to acid gas in the storage process, otherwise, it will change the color and reduce color fastness. Most of the X-type reactive dyes are used rarely because it is prone to occur bond breaking phenomenon and it is easy to fade when stored.