Alternative carbon blacks
The development of black inks and pigments that are derived from sources other than petroleum and are even proven to be carbon-negative could be a game-changer in the apparel industry and beyond. Enterprising companies are exploring biomass, waste and by-products, even soot itself, to make a greener version of a colour that fashion cannot live without.
It is a colour found in nearly every product under the sun, from the rubber of tyres and shoe soles to plastics, electronics, and beyond, including, yes, inks for printing on paper. In fashion, its presence is nearly as dominant, it is its absence that would really shake up the industry and make headlines. Speaking of which, how many articles begin with “X is the new black”?
In its traditional form, produced by the incomplete combustion of petroleum products (and agricultural waste), carbon black is considered “possibly carcinogenic to humans”, a Group 2B substance, by the World Health Organisation’s International Agency for Research on Cancer (IARC). Despite its hazardous nature, it is not banned.
Eco-conscious brands are beginning to take notice of how frequently black, from inks or pigments, are used to make their products, from textiles to hangtags to packaging, and are reaching out to innovative companies that are developing alternatives. Patagonia now prints all of its hangtags with Living Ink’s Algae Ink, and it says tests are under way with six of the top ten sports brands. Hemp Black’s eco6, a biomass black ink, is in trials at companies operating in nine different countries and in 13 different sectors, says Andrew Mark Sunderland, company founder and head of innovation and sustainability.
One of the research projects at Amsterdam-based sustainability organisation Fashion for Good is also looking into the potential of next-generation, biomass- or pollution-based carbon blacks as a possible solution for dope-dyeing. It has chosen three possible options, made by Living Ink, Nature Coatings and Graviky Labs. Birla Cellulose, in India, is working on a solution for manmade cellulosic (MMC) fibres, and Paradise Textiles, in Taiwan, on one for recycled polyester. Brand partners in the consortium include Bestseller, Kering and PVH. Thus far, the organisation says, all three alternative carbon blacks have mainly been used for printing. The project thus seeks to assist them in developing formulations for dope dyeing.
In the initial phase of the pilot, running in the first half of 2022, Birla Cellulose and Paradise Textiles will be producing the first dope-dyed MMC fibres and rPet yarns. “Participating Fashion for Good partners will have the opportunity to evaluate the performance, colour fastness, wearability and impact of all solutions. Successful formulations will then go on to trial larger production runs with fabrics dyed using the innovations in phase two, which is scheduled to kick off in the second half of this year. The results of the project will be shared publicly with the industry at large at the end of phase two,” says Katrin Ley, Fashion for Good managing director.
Dope-dyeing is “a very sustainable way of creating a coloured yarn,” says Jane Palmer, CEO and founder of Nature Coatings. “It requires less water, less energy and less time too.” Each type of yarn, she adds, requires a specific formulation.
Los Angeles-based company has been busy developing a water-based dispersion pigment that can be mixed with any paste or formulation at a mill. “We leap-frogged our technology and can now offer a dispersion product that is 100% plant-based, eliminating fossil fuels altogether,” she tells WSA. A Life Cycle Assessment (LCA) is under way and initial results indicate that its pigment is carbon-negative. Nature Coatings has conducted extensive testing to demonstrate the safety of its solution. “It passes the EU standard for children’s toys and has been included in the Oekotex Eco-passport and ZDHC MRSL 2.0 Gateway,” she says.
Nature Coatings makes its black pigment from FSC-certified wood waste. A resource available in great quantities; 50 million tonnes are generated yearly in the US alone, says Ms Palmer. The company currently produces its pigment in the US and Europe and has plans to set up a plant in South-East Asia. “We want to be able to service our customers faster. This network will save money, time and shipping, in addition to further lowering the product’s carbon footprint,” she says.
In addition to the many tests under way with major sports brands — including Patagonia’s hangtags, via global label specialist Avery Dennison, and its first commercial product with innovative British performance brand Vollebak last year — Living Ink is working on developments in many applications, including leather, Scott Fulbright, CEO and co-founder of the Colorado-based start-up, tells WSA. He adds that the Fashion for Good pilot programme is not only a great opportunity but also a key learning experience. “It enables us to tweak our process and iterate new formulations for the textile industry,” he says.
Living Ink’s Algae Ink is made from a by-product of an algae growing operation. As such it is considered a waste product, and because it “locks in” carbon into the ink forever, it is also a carbon-negative material. This is backed by an LCA conducted by researchers at the University of Colorado in Denver. “Carbon is locked in and won’t be released back into the atmosphere. The ink does not biodegrade, but it is safe, inert, and can be composted. If a brand’s priority is carbon, we are the solution,” says Mr Fulbright.
Carbon is more or less present everywhere on earth, and of course in the carbon dioxide (CO2) that modern society generates, but it is also found in high concentrations in particulate matter. “In India, particulate matter emissions can reach 1000 ppm from November to March every year when farmers burn crop residues. These are far more dangerous than carbon dioxide to human health and global warming,” says Graviky Labs CEO, Nikhil Kaushik. The MIT spin-off founded in 2016 and based in Mumbai sees itself not as an ink specialist but as a company that captures carbon and finds uses for it in everyday materials.
Graviky Labs has started making its black ink from soot, not CO2. “Soot is made up of unburnt particles from combustion. It is very a carbon-rich substance that can have up to 98% carbon,” says Mr Kaushik. The company collects soot directly from factory smokestacks in India. It purifies this material, removing any unwanted substances such as heavy metals. It began by making inks for artists and has since developed formulations for screen printing and offset printing. In fashion, Graviky Labs’ Air-Ink was used by Pangaia, before the company joined the Fashion for Good project.
Carbon-negative is good
Hemp Black, a company based in Georgetown, Kentucky, develops an entire suite of products from the plant, including an alternative carbon black it calls eco6. The patent-pending ink is made from the hurd (or stalk) of the hemp plant through pyrolysis to obtain biochar. This material is then ground into powder in varying qualities for different markets, from plastics to mascara.
“In the last six to eight months, we have been working specifically on developing eco6,” says the founder, Mr Sunderland. Its biomass-derived carbon black is, as mentioned, being tested across 13 different product categories. “All results are proving to be one-for-one replacements for petroleum carbon black,” he says. The company’s eco6 technology is the first carbon black alternative to achieve Platinum Material Health certification from the Cradle to Cradle Innovation Institute.
Mr Sunderland holds seven patents for innovative hemp-based products covering a wide array of applications within Hemp Black’s business portfolio. A derivative of CBD oil is integrated into yarns and used to make seamless performance clothing enhanced with the anti-odour and antibacterial properties of hemp. A specific strain of hemp is being tested for its potential as a hemp fibre for textile applications in southwest Texas. Hemp Black is part of Australian hemp specialist Ecofibre, which has extensive experience in hemp genetics and breeding.
Hemp Black’s eco6 is available as a printing ink, and it has been used for solution dyeing and garment dyeing, says Mr Sunderland. The company currently operates one pyrolysis line whose production capacity is 700 tonnes of char yearly.
Mr Sunderland’s latest research has focused on measuring hemp’s ability to sequester carbon when it grows, and assessing how much carbon is captured in its eco6 ink. As all plants do, hemp naturally transforms CO2 into oxygen. Hemp pulls carbon dioxide from the air at a rate that can be three times that of trees, says Hemp Black, based on research by Darshil Shah at Cambridge University. Its cultivation also enriches and regenerates soil. “Hemp can be grown on fields during fallow periods,” says Mr Sunderland.
Furthermore, the carbon in the hemp hurd is permanently fixed into biochar. Petroleum carbon black also sequesters carbon, but its manufacture releases 2.4 kg of CO2, according to a 2020 carbon footprint statement by Birla Carbon, a leading supplier of conventional carbon black. Research at Hemp Black shows that eco6 sequesters 6.8 kg of CO2. “A few years back, we didn’t know anything about hemp’s ability to sequester carbon. Now we have the data, drawn directly from our own operations, and we can share it with brands,” says Mr Sunderland.
Making carbon black from biomass, and especially from hemp biomass, is a natural fit, he insists. “Hemp is one of the few carbon-negative materials, and it is a whole economy,” he likes to say.
The challenge remains to achieve the performance levels that the industry is used to with petroleum-based products, says Ms Palmer, at Nature Coatings. As brands increasingly seek to reduce their carbon footprint, choosing a colour that is not only capable of locking in carbon but also has a ubiquitous if not universal role, gives it a temptingly green twist.
British performance wear brand Vollebak introduced an Algae Ink by Living Ink T-shirt last year.
Credit: Vollebak
