The NOX reactor of Greendye (Source: Karl Mayer)
Jeans are indispensable for the clothing industry, but are increasingly criticized for their negative impact on the environment. Karl Mayer Rotal, the site with the denim center of excellence of the Karl Mayer group, Obertshausen/Germany, has developed Greendye, a technology that offers sustainability and at the same time more economic efficiency than conventional plants.
The premiere machine goes to Taiwan, to the innovative global player Nien Hsing Textile, Taipei/Taiwan. In warp preparation, the environmentally conscious denim player aims to improve its eco-balance, especially with Karl Mayer's Greendye unit.
With Greendye, indigo dyeing is 2 times cleaner and at the same time 3 times more efficient than with the processes of conventional equipment. The basis for the very good performance is the use of nitrogen (NOX) technology to control the chemical dyeing process. In the NOX reactor, the indigo dye has time to create a more solid physical bond into the fiber composite, adhere there and be fixed. It is also possible to increase the indigo concentration in the dye bath. These effects enable the yarn to absorb three times more dye than in case of conventional processes.
Further advantages result from the design of the dyeing vats. A high-flow, low-speed indigo circulation system and a design that avoids turbulence and surface foaming significantly reduce chemical consumption. A saving of up to 50% of hydrosulfite and caustic soda, thus a halving of the gray water footprint is possible. A reduction of 50% is also possible in the final washing water consumption.