Get to Know Your Dyes
Not all dyes are equal and depending on the effect and colour you want to achieve and the material you want to use, it is important to understand what dyes are best suited for your needs. The most commonly used dyes are either reactive or pigment. Reactive dyes are less likely to fade over time and give a consistent solid colour that doesn’t easily bleed or transfer onto other materials. A significant amount of salt is added in the process to increase colour fastness, and since salt and dyes are water-soluble, it is difficult to eliminate toxic biological waste effluents which are linked to significant environmental issues.
Alternatively, pigment dyes can produce incredibly vibrant and rich colours, while also giving off a soft aged appearance. Pigment dyeing does not create a chemical reaction, but instead acts as a binding paste of colour that is insoluble in water but sticks to materials.
Reactive dyes are most typically used on cellulose fibres like cotton, silk, rayon, linen and hemp, while pigment dyes tend to be used on polyester and cotton/poly blends and require additional silicone wash for softness.
Most Common Doesn’t Always Mean Most Friendly
Azo dyes are the most common form of dyeing within the textile industry, making up approximately 70% of all commercial dyes (like reactive and pigment) and refers to direct dyes which don’t require a mordant to bind the colour to the material. As the dyes are resistant to waste effluent treatments, they are considered known carcinogens. It is predicted that as well as salt and fixing agents, mill waste effluent contains between 5-20% of original dyestuff that seeps into the natural environment affecting biodiversity.
While carcinogenic, they are commonly used because they are able to dye textiles at a lower temperature than azo-free dyes and offer a more vibrant range of colours that don’t easily bleed. Azo-free refers to any dyes that do not contain the main known carcinogenic compounds that have been regulated by the EU. The main countries that dye textiles tend to be in Asia and India and do not have the same strict regulations as in the EU, although legislation is slowing changing. As concerns for the environment and local communities rise, azo-free dyes are becoming increasingly popular and development into safer dyeing methods is following suit.
The Future Is Bright with Innovation
The Indian government has recently become more stringent on precious water resources, and a large majority of chemical factories in India now reuse around 90% of their water.
The largest suppliers of dyes and textile chemicals are Huntsman, Archroma and Dystar, and they are all leaders in exploring innovative ways to be more environmentally responsible around Asia and India.
Huntsman are trying to reduce their chemical and water usage and have recently developed a line of dyes called Avitera that more readily binds to cotton to use ¼ less water and ⅓ less energy than conventional dyeing methods that require multiple washes and creates vast amounts of effluent.
Wrangler, one of the largest denim brands worldwide, have introduced Indigood- a foam dye that eliminates wastewater entirely from the indigo dyeing processing of denim. In 2017 Deakin University became one of the recipients of the Global Change Awards for their denim-dyed denim. Their newly founded technology is able to also eliminate 100% of the water in the dyeing process by using one old pair of denim jeans to dye ten new ones – reducing 200 litres of water (the average amount of water to dye one pair of jeans conventionally).
Other companies like ColorZen are also exploring different ways to be more resourceful. ColorZen focuses on pretreatment processes for cotton dyeing and has found a method that uses 90% less water, 75% less energy and 90% fewer hazardous chemicals compared to conventional dyeing processes. Alternatively, hybrid pigmentation is increasingly becoming a more viable dyeing option.
Ecofoot recently developed a hybrid pigment that reacts with cellulosic fibres without the need for salt in temperatures as low as 25 degrees. Other companies, such as Colorifix and Faber Futures are exploring biological ways of working with bacteria instead of chemicals to colour textiles by working with bacteria DNA cells to alter natural pigmentation processes.
Since almost 20% of global water pollution is linked to textile dyeing, it is crucial to consider more environmentally friendly options. As factories are looking into resource use and trying to find better long-term efficient and cost-effective solutions, it is increasingly easier to find azo-free dyes and dye alternatives in both Europe and Asia. The industry is moving towards lower impact options at the pre-treatment phases as well as during the chemical producing and dyeing, making after-care for customers easier and safer, as well as lowering the overall environmental footprint of the processes.
Water resource efficiency has been making monumental strides in recent years and companies are experimenting with the possibility of eliminating water usage outright to tackle effluent runoff issues. Overall, the future of textile dyeing is looking more and more eco-friendly, and governmental legislations are encouraging this move with stricter regulations globally.
The Cycle Starts and Ends with Dyes
There have been major developments into end of life management with dyes, and the take, make, dispose and pollute model is slowly being replaced with a circular model that ensures longevity and minimal waste through the recycling of dyes. Technology is constantly improving to allow for more efficient systems, and companies are very recently finding solutions and alternatives to single-use dyestuff. While some companies have been exploring effluent waste management, other companies like Recycrom have founded a new technology to recover pigmentation from textile waste.
Recycrom creates a large variety of pigment powders using just textile fibres from discarded clothing and production waste using only natural chemicals. As it is applied as a suspension rather than as part of a chemical solution, the excess dyestuff is easily filtered from the water so it doesn’t affect the natural environment. Brands are encouraged to collaborate with Recycrom and Officina+39 who manage their chemicals in Italy to create custom dyes from their own textile waste.
Though eco-alternative dye options are appearing in the market, they are still not the most commonly used as of yet.
It is crucial to consider the entire life cycle from pretreatment processes, to recovery and reuse of pigmentation, and with lots of textile and chemical companies rigorously innovating at competitive costs there is no excuse to ignore these eco-friendly alternatives.
Certifications to Keep an Eye Out For
The main dye certifications to look out for include:
- GOTS (Global Organic Textile Standard)
- OEKO-TEX Standard 100
- REACH (Registration, Evaluation, Authorization and Restrictions of Chemicals)