Classic Denim Fabrics Can Be Sustainable:
How To Upgrade Existing Rope Dyeing Ranges With A Double Operational System

MACHERIO, Italy — December 18, 2023 — During ITMA/23, MASTER S.R.L. launched the revolutionary machines “CRAFTYFLOW” and “CRAFTYROPE” for the dyeing of denim warps with indigo and sulphur dyes: they are the only ones that, thanks to their dual-technology can work both in air, as usually done today, and in nitrogen atmosphere with ecological and economical advantages.

These machines are the results of several trials and the evolution of the concepts utilized in our original dyeing system in nitrogen atmosphere, based on the insertion in classic dyeing ranges of special modules (Genius). This system had been first adopted by M/s Bluref, pioneer of this technology, and, afterwards by other famous producers such as Covolan Ind. Textie, Candiani Denim, Sasha Denim, Advance Denim.

In order to develop our “CRAFTYFLOW” and “CRAFTYROPE”, we, at Master, have carried out several trials and experiments that have confirmed our new concepts and construction design, and that have also highlighted that the new multi-box concept is assuring many advantages in the process adjustment and higher flexibility compared with the previous idea of inserting specific modules.

Thanks to all these researches and experiments, we are glad to announce that we have developed and patented the possibility to extend the concept of dual-technology also to existing and already running indigo rope dyeing machines, the most commonly used, giving them a new future.

This technology upgrading on existing dyeing ranges requires a limited investment and can be realized on site in a simply way and with short machine down time. Basically, it consists of completing a number of dyeing boxes (we suggest up to 50%) with special devices and components allowing, from one side, to continue to work in the traditional way and, on the other one, using the nitrogen atmosphere.

In this way, it is possible to continue producing classic running qualities, but also to introduce new exclusive developments with better quality, less cost and ecologically sustainable.

In fact, thanks to this upgrading, existing machines will be able to continue to run usual indigo dyeing processes, but with the possibility to add bottoming or topping (or both of them) using nitrogen technology, as well as to dye pure sulphur colors without the need of a steamer achieving the highest quality levels, better fastness and brightness.

Using this advanced nitrogen technology, in case of sulphur colors, especially in case of black, a higher dye stuff use efficiency can be achieved, and it can be estimated, at a visual check, approximately +40% compared with traditional dyeing technology.

Moreover, the same upgrading allows to dye indigo in an ecological way, with a reduced number of boxes, using only one fifth of dye bath, saving up to 70% of hydrosulphite and caustic soda. The process can be designed both with low and high indigo concentration and temperature. In any case, thanks to the better indigo fixation, the result will bring also to a higher dye stuff use efficiency, better fastness and a saving of water in washing boxes with consequent reduction of production costs.

Thanks to nitrogen technology, indigo in the dye bath is totally and perfectly reduced up to a nanometric level and, in this condition, the resulting color fixation is much better and stronger compared with traditional system operating in air. This is the reason why, in this way, it is possible to achieve a better dye stuff use efficiency, a better fastness, intensity and brightness.

All what above explains why this innovative dyeing system is the only one that we can call “ecologic” as it brings to a reduction of dyeing bath volume, number of dips and oxidators, all conditions necessary for a drastic reduction of polluting chemicals, power and water consumption, being this last one of the most critical topics nowadays (see IndigoNews n. 2)

Concerning ecology issues, among the most urgent worldwide, many consumers protection organization are asking for an international law, to be introduced as soon as possible, to impose the reduction of chemicals consumptions and the respect of regulations to protect health and the environment.

Further, it is important to underline that this new dyeing system allows, in any case, to play with all those typical parameters – physical, chemical, mechanical and technical – of dyeing processes to achieve the desired final results.

Unfortunately, over nearly twenty years after its invention, dyeing with nitrogen technology has not spread as expected due to a few reasons, the first one, the lack of technical knowledge and the underestimation of the enormous advantages they were offering by the potential utilizers.

In fact, many producers, although sensitive to ecology, have believed that they could achieve the desired eco-targets by simply applying some devices to their machines, such as ultrasound, etc., which are, actually, only palliatives capable to bring limited improvements, but nothing that can allow the reduction of dangerous and polluting chemicals.

Today, even if this new modern, experimented and suitable nitrogen technology is available, analyzing actual denim production, it comes out very clearly that, despite everyone making of ecological issues their banner, the majority, or rather almost all, of the denims on the market, are still dyed with the old classic method in open air, that is to say, anti-ecological.

Unfortunately, this situation persists even if many brands are asking for a more sustainable and ecologic denim and despite the fact that the new fabrics that can be obtained with the nitrogen technology may offer designers the possibility to offer new and innovative garments.

All together, it is evident that this anomalous situation can not be supported for long in the globalized environment we are living.
Denim producers have to face the imperative ecological and moral obligation to change their production mentality, to innovate/update their classic dyeing machinery to reduce the consumption of chemicals, water and power and to adopt everything necessary to offer ecological and sustainable products, achieving, by the way, cost reduction advantages.

Summarizing, the updating of existing rope dyeing machines for the use of the dual- technology, will assure the possibility to operate as shown in the attached drawing no.12825, that is to say:

  • Indigo dyeing as per traditional method, in air, using all the available boxes at full level with low dye bath concentration. These dyeing processes can be completed, with bottoming, topping, sandwich sulphur colors dyed with nitrogen technology, for never-before achieved results.
  • Indigo dyeing – new ecological system with high dye stuff use efficiency – using nitrogen technology, half of the dye boxes, low dye bath level (one sixth of the total volume) and higher dye stuff concentration, achieving:
    • 50 to 70% reduction of caustic soda and hydrosulphite
    • 30% reduction of power consumption
    • Reduction of total production costs
    • Higher dye bath circulation rate (thanks to its reduced volume) with the result of 
a better exchange dye bath-fibre and, thus, better general dyeing results 
-  Possibility to develop new, original and exclusive articles, not achievable on 
traditional machines
    • Sulphur dyeing processes with high dye stuff utilization efficiency, better 
fixation, no need of steamer and better brightness compared with those on traditional dyeing machines operating in air. 
To be noted that there is absolutely no nitrogen consumption during the dyeing process, except for the initial filling.

The upgrading above described is the bright, smart and economic solution to give life to the eco-sustainable denim for the future.

MASTER is integrating tradition with flexibility, economy and sustainability.

Posted: December 18, 2023

Source: MASTER S.R.L.