Dyeing Greener Fabrics
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Dyeing Greener Fabrics

6:09 AM, 10th June 2019
Dyeing Greener Fabrics

Underneath the layers of brilliantly coloured fabrics, textile dyeing is one of the major pollutant causing industry globally. What the industry needs is a new approach towards dyeing with environmental sensitivity at its core.

By Debarati Das

Who doesn’t like a wardrobe full of colourful clothes!! But while choosing the right shade of the garment, how much thought do we put into the amount of environmental damage that the pair of faded blue jeans or the scarlet dress has caused?

Among various industries, the dye industry is a major pollutant causing industries. So much so, that several countries across the globe have started taking strict action against environmental pollution caused by textile dyes. China recently shutdown several factories that produce synthetic dyes used by the textile industry. India, the second largest textile market, is taking cognisance of the water pollution caused by the industry and is putting in waste water treatment in place. Similarly, other countries too are bringing in stringent rules to curb textile dyeing pollution.

However, the need here is to bring a massive change in the root cause of this global predicament- the ‘Dyes’. There is a need to make the dyes and the dyeing process more environment friendly.

Industry Insight

The global textile industry is nearly a $3 trillion business but while it weaves radiantly coloured fabrics, it is also the cause for huge amount of environment pollution. According to the World Bank, textile-dyeing accounts for up to one-fifth of the world's industrial water pollution. To put the plight in numbers:

Approximately 10 to 15 percent of the dyes used during the dyeing process are released into the waste water.

About 40 percent of the globally used colourants contain organically bound chlorine which is a carcinogen.

Cotton, one of the most popular fabrics, takes up only about 75 percent of the dye and the dyed fabric is washed over and over to ensure colorfastness, resulting in huge amount of wastewater. About 200 liters of water is used to produce just 1 kg of fabric.

Heavy metals present in textile industry effluents include chromium, arsenic, copper and zinc, which are not biodegradable and hence affect the aquatic, flora, fauna and human lives alike.

The industry has to make a collective effort in making dyeing process eco-friendly, safe and yet affordable.

Weaving Sustainable 

Let’s be realistic. Demand for clothes is never going to go down, courtesy- the ever rising population, rising fashion trends and increasing disposable income. However, to solve this problem, dye makers across the globe are looking at new technologies and methods that would make textile dye sustainable while minimising the environmental risks.

Here are some of the latest innovations that are being accepted by the industry:

Going Digital: One of the major concerns about the textile industry is the amount of water wastage that happens in the process where fabrics have to be washed over and over again till the colours sticks to the fabric. Manufacturers are therefore switching from dyes to pigments. Intech Digital, a company that specialises in digital printing on textiles, makes large-scale printers that use special versions of ink-jet printheads designed to work with textile inks. Digital printing can be done on a range of fabrics including cotton and other cellulosic fabrics like rayon and uses and wastes much less water than traditional methods.

Steadfast Colours: If you still want to stick to the traditional dyeing methods, then how do you solve the issue of eliminating the wastage of water?  By making the dye stick to the fabric faster. Huntsman has a line of polyreactive dyes for cotton called Avitera that bonds to the fiber more readily and saves water and energy by 50 percent. Three reactive groups are attached to the dye formula’s chromophore compared with the one or two reactive groups common for cotton dyes. As a result, compared to the seven hours for conventional dyeing process, Huntsman’s dyeing process takes about four hours. Avitera dyes are also free from p-chloroaniline (PCA), a hazardous chemical used as an intermediate in the manufacture of azo dyes and pigments. Today, several international brands restrict the use of PCA and other amines from colourants. “Huntsman Textile Effects introduced AVITERA® SE to help the industry address its most pressing economic and environmental sustainability challenges. We continue to develop this technology to help textile mills and brands achieve cost-effective production, improved textile products and minimal environmental impact,” said Paul Hulme, global president, Huntsman Textile Effects.

Nip it at the seed: Cotton is the most commonly used and the most comfortable fabric for daily wear. But cotton is also the raw material which causes maximum amount of environmental damages. ColourZen came up with a pre-treatment technology that would solve most of the problem right in the seed. In conventional cotton dyeing, salt is used to negate the charge on the surface of the cotton. ColorZen technology uses a quaternary ammonium compound to permanently attach a positively charged amino site on the cellulose molecule that makes for a natural attraction between dye and fiber. The pre-treatment is done on raw cotton fiber right from the field after the seeds are removed. With this pre-treatment, there is a 50 percent reduction in dyestuff, 97 percent dye retention, 90 percent less water, 75 percent less energy, and 90 percent fewer auxiliary chemicals.

Dyeing Blues: We all have a pair of blue jeans. But each pair of blue jeans creates a havoc in the environment before it reaches your wardrobe. Synthetic indigo, that gives the blue hue to the jeans, releases unreacted chemicals downstream of manufacturing. In its unreduced form, indigo is not soluble. And hence manufacturers produce indigo using aniline as a key raw material.

To counter the dangers of aniline, Archroma developed a technology for prereducing indigo to prevent aniline from carrying through as a contaminant. According to Archroma, finished textiles coloured with the dye contain a nondetectable amount of aniline compared to competitor dyes that contain up to 2,000 ppm of the chemical.

“The company became concerned after seeing published reports that about 400 metric tons of aniline per year escapes the dyeing process from 70,000 metric tons of indigo. Two-thirds of the escaped chemical ends up in wastewater, on workers, and in the air, while one-third stays on the denim that goes to stores,” said James Carnahan, global sustainability manager for textiles, Archroma.

Natural Colours: Archroma patented new method of creating natural shades from high-performance dyes which are synthesized from non-edible agricultural or herbal industries waste such as leaves or nutshells. These natural shades can be used for cellulosic based fibres such as cotton, viscose, linen, bamboo, kapok, etc.

Archroma has tied up with several garment manufacturers including jeans manufacturer, G-Star RAW, and travel and adventure apparel brand- Kathmandu, where the patented EarthColors are used.

Archroma’s line of EarthColors include Dark Plum, Asfalt, Mazarine Blue, slate blue, burnt olive and burlwood rose, etc which are made from the non-edible parts of nutshells, almond shells, rosemary, saw palmetto, bitter orange, beetroot and saw palmetto.

“Creating sustainable solutions is a journey: EarthColors was more than five years in the making and the project is still evolving in our laboratories. With the planet reaching the limit of its resources, we need to offer more sustainable options to the consumers. That is why we spare no efforts to develop groundbreaking innovations in the deep belief that we can make our industry sustainable. It’s our nature,” said Manel Domingo, R&D head for special dyes at Archroma, who developed the EarthColors technology.

On the other hand, Colorifix developed a dyeing technology where genetically modified microbes are used to produce stable colours. Colorifix’s range of colours are produced naturally by organisms such as microbes, plants, animals and insects. Microorganisms engineered with advanced synthetic biology methods convert agricultural by-products, such as sugar molasses, into colorants suitable for textile dyeing. According to Colorifix, the process enhances the microorganisms’ natural ability to directly transfer the colour onto fabric, saving water and energy. The process uses ten times less water than traditional dyeing methods and no heavy metals, organic solvents or acids. “Our investors are passionate about our mission towards the environment and will certainly help us on the long road to changing a global industry,” said Dr Orr Yarkoni, CEO, Colorifix.

While damages cannot be undone, textile manufacturers, dyes manufacturers and apparel brands are collectively taking cognisance of the grave danger that is being done to the environment and trying to make amends. “Almost everyone has a pair of jeans in their closet.  As a key player in this market, G-Star RAW takes responsibility to lead by example in promoting sustainable denim innovation. We would like to invite others to join us towards cleaner and more ethical denim production globally,” said Frouke Bruinsma, corporate responsibility director of G-Star RAW.

Probably, it is time for the consumers to join this equation and put an extra effort to check the sustainability quotient of the apparel they buy.

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