The dyeing process takes place in three distinct phases:
Adsorption and Diffusion
The reactive dye is adsorbed onto the cellulose surface and then diffuses into the fiber matrix.
Fixation
If conditions are favorable (high temperature and/or high pH), the reactive dye reacts with active sites in the cellulose during this phase (fixation), resulting in a strong covalent bond.
Washing Off
To obtain the required fastness properties, all these forms of unfixed, adsorbed dye molecules must be washed off the fiber.
Industrial practice has shown that with AVITERA SE, nearly 90 percent of the dye applied to cotton during dyeing is fixed, as opposed to 60 to 80 percent with conventional reactive dyes. This ensures higher yield.
Fabrics can be dyed and washed off at different temperatures and different quantities of water. Hot dyeing systems require a temperature of 176°F (80°C) to make the bond between dyestuff and fabric permanent. These systems also require boiling water and several rinsing baths to completely remove unfixed dyestuffs.
Conventional warm dyeing systems already offer the benefit of creating the necessary bonds at a lower temperature—140°F (60°C)—but still require a lot of water and high temperature for an appropriate wash-off.
AVITERA SE dyes help significantly reduce water and energy consumption and CO2 emissions since dyeing and the washing-off process never exceeds 60°C.With only five percent or less unfixed dye needing to be removed, instead of the usual 15 to 30 percent, the number of rinsing baths to obtain the required fastness properties is greatly reduced.
To ensure that AVITERA SE dyes achieve the targeted resource and cost savings, they must be correctly applied. Huntsman Textile Effects works closely with textile mills to adapt their production processes and guarantee excellence in operation, strict cost control and a sustainable system. Helping brands and retailers to coordinate with mills and communicate with consumers improves cooperation throughout the textile value chain, resulting in greater environmental awareness and more sustainable textile processing.