Recycled Materials ‘Not Good Enough’ Says Startup Whose Synthetic Tights ‘Fully Biodegrade In Landfill’

It is common knowledge that our throwaway clothing culture is contributing millions of tonnes to landfill waste every year. The majority of these clothes contain synthetic fibers like polyester and nylon, which release micro plastics during washing, wear, and disposal. Circular economy business models have fast emerged to divert apparel and footwear from landfills into resale, rental, and recycling. But there is a category of products that typically do not meet the criteria for these avenues due to product fragility, hygiene restrictions, and recycling limitations—hosiery. As many as 8 billion pairs of tights are made, worn a handful of times, and discarded every year. Statista reports that the tights and leggings segment of hosiery is expected to grow in volume to 387 billion pieces per year by 2025. Tights in landfills biodegrade into plastic fragments that leach into waterways, contributing to micro plastic pollution. Sophie Billi-Hardwick, 33, and Marie Bouhier, 27, cofounded Billi London two years ago to address this problem. They set about creating a sustainable tights product and say they now “own 100% of the biodegradable tights market” as hosiery industry behemoths lag behind. 

The journey to launching biodegradable tights took 2 years of research and development by the two entrepreneurs, who had no previous experience in the hosiery industry. The duo visited 5 tights factories in Europe and conducted extensive research into biodegradable synthetic yarns and consumer attitudes towards tights. They discovered that of 300 tights-wearing consumers, most of them typically “binned 1-2 pairs per month” which was creating guilt (due to the waste generated) and a reluctance to continue wearing tights, given their cost and negative environmental impact. Having researched biodegradable nylons in apparel products during a Master’s degree at London College of Fashion, Maire Bouhier wondered why this innovation was not being applied to tights usually knitted from nylon and elastane yarns.  

Additional research by Bouhier and Billi-Hardwick, who joined forces in 2019, unearthed two yarn suppliers willing to supply enhanced versions of both nylon 6.6 (the type typically used in tights) and elastane. The enhancement was a change in the molecular structure of both the nylon and elastane that make them susceptible to microbes. This susceptibility leads to “digestion” of the nylon and elastane by microbes in landfills, resulting in non-toxic byproducts and no micro plastics. But with this improved biodegradability comes additional complexity in the handling of the yarn and the creation of a high-quality and high-performance product, and this is what the entrepreneurs believe is hindering the widespread adoption of these yarns, which are readily available from suppliers in Europe.  

To use these yarns, which are optimized for apparel products, not tights, Billi London partnered with a tights manufacturer to utilize specific knitting machine technology with a high degree of specificity when it comes to combining nylon and elastane and programming the knitted structure and specifications of the tights. Two years of R&D, wearer trials, and external biodegradability testing and certification indicate that disrupting the tights market is something only a scrappy startup on a singular mission seems willing to embark on. Their nearest competitor (a global tights brand) uses just a portion of biodegradable yarn in their comparable product. However, the entrepreneurs conceded that they do not have a total biodegradable tights solution, and currently, can only offer one thickness of tights (30 denier, which retail at around $32 ) while they troubleshoot problems with their thinner 15 denier tights prototypes, where the challenges posed by the biodegradable yarn properties are heightened. 

Having worked briefly in the tights sector myself, I know what a challenge this product can pose, both in terms of performance and the inbuilt seasonality, with demand ebbing for around half of the year. However, Billi-Hardwick revealed during our interview that “socks and leggings are next on the agenda” for biodegradable disruption. Given that these products typically include at least some synthetic fibers (often elastane) for stretch and recovery, this seems a brilliant move. It also seems smart given that the startup is soon to launch a funding round ahead of market expansion plans, which will no doubt be catapulted by a universal product like socks.  

On the subject of biodegradability credentials, I dug into the conditions required for optimal breakdown with a degree of skepticism. I have often seen biodegradability and compostability data based on highly specific (and inaccessible) conditions. Billi London bucks this trend. Bouhier explained that the tights require “biodegradability conditions of a well-controlled landfill—which now represents the majority of landfills in the EU”. Such landfills are characterized by “high humidity, an absence of oxygen and high (levels of) specific anaerobic bacteria that produce (organic compounds) biogas and biomass”. Biodegradability tests have demonstrated that Billi London tights biodegrade within 5 years, versus 40-100 years for traditional tights. Clarifying a common question over composting as an optional disposal method, Bouhier explained that “it doesn’t work (for Billi tights) because (composting is) not anaerobic”.   

On the direction of the startup and its founding values, Billi-Hardwick said “something extremely important and in our DNA (is) we want to bring innovation into the market. We have a challenger mindset”. When asked about the long term vision for the company, she said “we want to build the brand as a material science and consumer goods brand. We really believe in partnerships, so we might join others and collaborate”, which echoes the ethos and business model of other sustainable product disruptors who I have recently interviewed.  

In weighing up recycling versus landfill for plastic waste (including synthetic fibers) it is useful to know that less than 10% of all plastic produced since 1950 has been recycled, with 79% in landfills or the natural environment (the remainder is incinerated, releasing CO2 and other hazardous additives into the atmosphere). Plastic recycling is complex and expensive, and the recycled material can be more expensive (and sometimes of lower quality) than the virgin equivalent. Separation of different synthetics materials is also a complication—for example, where traditional nylon and elastane are mixed. As a result, micro plastic particles from degrading plastics in our environment are reaching catastrophic levels. “Aggravated by the COVID-19 pandemic, plastic waste has become a major part of the global pollution crisis, along with biodiversity loss and climate change.” This represents a “triple emergency” that must be tackled, according to a recent UNEP report. The report also demonstrated how the world’s most marginalized populations are bearing the brunt of plastic pollution impacts.  

Global brands are beginning to take a stake in such solutions, as evidenced by materials science partnerships and investments, buoyed by consumers becoming increasingly vigilant about the environmental consequences of plastics. But saddled with entrenched material sourcing and manufacturing processes, incumbent market leaders in product categories such as tights may lack the impetus and “challenger mindset” (as quoted by Billi-Hardwick) to embark on innovation journeys. Such initiatives can be seen as expensive, risky, and a threat to the bottom line. But the toxic consequences of plastic material waste from commercially successful products can no longer hide behind the business mantra ‘if it ain’t broke, don’t fix it’. The planet is broken, and innovation offers the promise of fixing it.