Diesel jeans made with Candiani’s Coreva denim
A most crucial topic in the denim apparel, textile and fiber industry much discussed in recent times is the biodegradability topic.
Following up a comment released by Luigi Caccia, founder, Pure Denim, during the last edition of Denim Premiere Vision in Milan in November 2022, The SPIN OFF has started further investigating about biodegradable stretch denim and in general about biodegradable stretch fibers, about how compostable and toxic they can be and similar connected topics.
Caccia stated that stretch denim cannot biodegrade because durable stretch fibers can only be achieved through vulcanisation, a process that alters fibers’ molecular structure. Therefore, according to the entrepreneur, only long-lasting and resistant products that can be passed to younger generations can be considered as truly sustainable. All the rest – and in particular stretch denim – could be highly polluting, especially if contained in fabrics in high percentages.
The SPIN OFF has asked some experts their opinion on the matter. It has also interviewed the first manufacturers that have achieved the first biodegradable denims, along with the first fiber producers, about the impact of their products with the aim to draw a first picture of the denim market about this specific aspect.
Stretch denim is a complex material, more complex than regular denim, which is already considered as a highly polluting fabric as it is produced by using different chemicals for dying it, then for treating and aging it. Giving for granted all this and knowing the industry has developed significantly by using less polluting dyes, has managed to reduce effluents by recycling water and finding alternative and low water consuming finishing methods, there are quite some virtuous examples that show how much the impact of denim has been reduced so far and that when some conditions exist, rigid denim can biodegrade.
Then comes the stretch problem. “Stretch denim which is conventionally made by blending cotton with elastane, a synthetic material, derived from finite fossil fuels, has a compromised biodegradability at its end of life. Moreover, as synthetic elastane is often blended with cotton, it cannot even be recycled once the jeans are thrown away as cotton cannot be separated from the stretch fiber,” said Philippa Grogan, a sustainability consultant who advises on sustainability, impact mitigation, communication, circular economy, textiles, fashion among others, underling why a stretch fiber used for denim can be hard to recycle.
Black or white?
Defining who is acting entirely right or wrong is not possible as each company’s or player’s attempt still shows some shadow zones, though some good examples can already be identified. “I cannot think that in the industry everything can be defined as black or white. Though I think it’s important that companies start setting strategies that include a product’s end of life, that is not the same for every material,” commented Giusy Bettoni, founder, C.L.A.S.S., a consulting company specialized in supporting textile companies in pursuing a sustainable approach.
“It’s not possible speaking about a biodegradable textile if it is not tied to standards that define if, for instance, a fiber is biodegradable or simply degradable. Moreover, a fabric to be considered as biodegradable has to satisfy two conditions: it has to degrade within a specific time-lapse and has to prove its eco-toxicity, which means that when it dissolves itself in the ground has to release substances that are not noxious for the environment,” she explained.
According to existing laws, there is not a dedicated certification process for compostable fabric yet. Therefore, in the industry they chose the closest material category possible they can refer which is packaging and, to be considered biodegradable a fiber or a material has to degrade 90% in 180 days, and has not to release toxic substances in the ground.
Some virtuous examples
In the denim industry there are many denim manufacturers that have grown increasingly conscious about the impact of their products and have started taking measures about how to reduce their impact on the environment by changing their production methods, how they source raw materials and how they finish their fabrics.
Among them, just a few ones until now have developed stretch denims that can biodegrade. They are Candiani Denim and Calik Denim.
Candiani Denim’s alternative
Candiani Denim has developed and patented Coreva, a technology that allows to create stretch denim fabrics that are biodegradable at their end of life.
“While most 100% cotton fabrics and apparel items engineered circularly, including 100% cotton denim, can degrade without compromising its quality or durability of course, at Candiani we wanted to offer the same possibilities to stretch denim too, reason why we developed Coreva,” explained Alberto Candiani, president, Candiani Denim.
Alberto Candiani, president, Candiani Denim
Coreva replaces conventional non-renewable, synthetic and petrol-based elastane with a renewable, plant-based alternative that is completely plastic-free as it it obtained from 100% natural rubber, sourced from the gum tree.
“The rubber fibers used for Coreva also pass through a vulcanization process, but unlike regular vulcanization processes, the fiber used by Coreva undergoes an innovative vulcanization process that produces no heavy metal residual and provides an elastic fiber which is fully biodegradable in that form,” added Candiani.
“Also all Coreva fabrics are fully recyclable since unlike synthetic elastomers, the actual rubber is easy to separate mechanically from the cotton due to its physical characteristics,” he continued.
Candiani Denim Coreva limited Denham
Considering its end of life cycle, Coreva has undergone tests to assess its biodegradability, disintegration and eco-toxicity and these tests when put together determine that denims made with Coreva are compostable.
“The tests that deter Coreva’s compostability were conducted at Innovhub(*), in compliance with EU standard EN13432,” explained Simon Giuliani, Candiani Denim. “This is the standard recognized by certifications such as Ok Compost although, at this time, they do not certify fabrics. Since there is not yet a dedicated certification process for compostable fabric, Innovhub selected the closest material category possible: packaging,” he explained.
Simon Giuliani, Candiani Denim
The test proved that Coreva stretch denim is compostable in mature compost in less than six months, without releasing the toxic chemicals and microplastics of conventional elastane,” continued Giuliani.
Calik Denim’s own solution
Also, Calik Denim has developed its new B210 technology, a solution based upon the application of an enzyme in the phase of yarn manufacturing. “Synthetic fibers need millions of years to biodegrade in nature. Thanks to our unique B210 technology, we have reduced the dissolving of products containing even synthetic fiber in nature to 210 days. Thanks to the special technology we have developed, B210 allows any kind of denim, including synthetic fiber, to dissolve in nature within 210 days,” said Cem Ozan Sari, R&D and P&D coordinator, Calik Denim.
Cem Ozan Sari, Calik Denim
Calik has tested and developed a special enzyme through which synthetic fibers can biodegrade, as proved by tests carried ahead by the company. “After testing under standard OECD 208, after analysis of the soil, after biodegradation, there is no toxicity problem for planting in the soil. In summary, we’re using an environmentally conscious integrated technology created as part of the process chain,” explained Sari.
The company has achieved such a result after specific tests. “We have third-party certification testing results from Intertek(**), according to the Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under High-Solids Anaerobic-Digestion Conditions (ASTM D5511-18),” explained Calik’s manager. “We have also achieved the certification for the toxicity as B210 fabric sample was subjected to anaerobic biodegradation as per ASTM D5511 for 210 days. After biodegradation, the soil was used for testing under OECD 208 standard,” said Sari.
Can biodegradable denim do good to the soil?
Candiani also did specifc tests to determine how Coreva acts when left to degrade in the ground. Not only the test confirmed that Coreva is compostable, and its disintegration has no harmful effects on plants and animals, which is technically referred to as eco-toxicity, but on the contrary it has a positive impact on it.
The company carried tests on different seeds and left them to rot in a pot with Coreva compost and in another pot with the control material compost. The results showed significantly better growth in Coreva compost as compared to the control material with growth levels of 23.9% and 22.5% higher plants for seeds left with Coreva compost than with the control material compost.
Also Calik made tests for checking what impact its fabrics had when left to compost in the ground. “As a result of the tests carried out, no negative effects on germination rate and no visible damage to plants was observed after leaving the fabric with B210 in the ground. Only a 0.04% quantity of non-degraded stretch fiber had remained in the soil and that is no longer harmful for it, as under OECD 208 standard,” explained Calik’s Sari.
The world of fibers
Stretch fiber manufacturers have also tried to develop their own solutions though, complete biodegradability hasn’t been achieved yet.
The Lycra fiber has recently announced it has signed an agreement with Qore LLC is about the development of a bio-derived fiber, but that is not biodegradable.
C&A jeans made with Roica V550 fiber
Roica, the Japanese chemical group, has developed Roica V550, a petrol-based stretch fiber that can degrade, but not biodegrade. Shinohe Hiroaki, assistanmt manager in Roica’s Next 50 Project team, explained some characteristics of the fiber: “We have developed a special polymer that is degradable. After tests, we found out that if the fiber is left to degrade in the apt conditions, after one year it degraded 10%, without releasing harmful substances in the soil, and after 24 months it dissolved more than 50%. Though we still don’t know if it will degrade entirely,” he explained. Along with that, the fiber has also achieved the C2C (Cradle-to-Cradle) Gold Level material health certificate and is also a Hohenstein Environment Certificated yarn, where at its end-of-life, it smartly breaks down without releasing any harmful materials.”Despite our fiber is not biodegradable, we think it is already a valid alternative to traditional stretch fibers as it releases less CO2 emissions than regular synthetic fibers,” added Hiroaki.
Defining the right regulations
As known in the market, and as previously pointed out by Candiani’s Giuliani, the textile industry still has no specific laws that regulate the standards for defining how can apparel degrade in order not to be noxious for the environment, despite new decisions are in progress.
“National and EU legislations are slowly approaching these matters,” commented Alberto Candiani, owner, Candiani Denim. “Composting a garment, for instance, is not even a thing at the moment, but it will certainly be in five years from now and that’s our job, reading the future so that our R&D can make such a vision a real innovation,” he added.
Candiani store in Milan showing Coreva denim biodegrading steps
Philippa Grogan, sustainability consultant, agrees on this topic. “Beyond the EN 13432, a European standard for packaging and packaging waste that stipulates a minimum amount of residue in a set time, there are some interesting textile regulations emerging under the EU Green Deal that could impact biodegradability and biodegradability claims,” she said.
“We have the Strategy for Sustainable and Circular Textiles, that will include sustainability-focused design requirements for textiles, transparent and complete consumer information, Digital Product Passports, and a harmonised EU extended producer responsibility (EPR) scheme. EPR schemes will render producers physically and financially responsible for waste generated by their products, so this is certain to impact biodegradability abilities and claims in one way or another,” she added.
Despite only a few fabric and textile manufacturers have achieved significant results when it comes to biodegradable textiles, new additional developments and innovation could soon be launched, but compliant regulations and standards should be fixed very soon to avoid any further damage and make sure that any new product can set a significant and truly beneficial step ahead.
(*) Innovhub is an Italiuan consulting comoamìny that is recognized as one of the leading companies conducting applied research, scientific-technical consulting, testing and analysis for solving specific technological and/or product problems.
(**) Intertek operates from the UK through more than 1,000 laboratories and offices in more than 100 countries and delivers testing, inspection and certification solutions for its customers’ operations and supply chains.