DuraTech™ by Microban® is a new antimicrobial treatment specifically developed for cotton products.

By Yihong Li and Xiuzhu Fei

Cotton is the most extensively grown non-food crop in the world,¹ and makes up a significant part of the global textiles market, accounting for a revenue share of greater than 39 percent in 2021.² Fabric manufacturers choose this organic material for its longevity, absorbency and color retention, while consumers appreciate its softness, breathability and comfort. However, the properties of cotton that make it well suited to use in clothing and home textiles also make it susceptible to the build-up of odor-causing bacteria.

Susceptibility To Microbes

Natural cotton fibers are made from cellulose with a permeable, hydrophilic structure, making them accessible to moisture, dead skin cells, food residue, airborne dust and other contaminants from the environment. The large surface areas of sheets, towels and other cotton products can easily trap environmental contaminants, making them vulnerable to colonization by a diverse community of microorganisms. Bacterial growth on cotton fabrics causes multiple undesirable outcomes — such as discoloration, odors and degradation of the fabric — worsening product performance and increasing laundering requirements. One solution to these problems is to incorporate antimicrobial technologies during the manufacturing process, enhancing the cleanliness of cotton products and extending their lifespans.

Current Antimicrobial Technologies

Antimicrobial treatments can be applied during the exhaustion or finishing step of fabric manufacturing to provide a wide range of benefits, including improved fabric durability, odor-causing bacteria prevention, a decrease in water- and energy-intensive laundry requirements, and a reduction in the quantity of chemicals required for fabric care. Cotton materials are often treated with metal-based antimicrobial agents, such as zinc- and silver-based products, some of which may pose potential environmental concerns³ or regulatory challenges. Alternatives like quaternary ammonium compounds are more sustainable than heavy metals, but may have reduced compatibility with other additives used during the cotton manufacturing process because of the presence of cationic ions within their chemical structure. In addition, some conventional cotton finishes can suffer from poor wash durability, as many antimicrobials are water-soluble, so the treatment can be easily stripped from textiles over time during washing.⁴

Durable Antimicrobial Finishes For Cotton

Huntersville, N.C.-based Microban International recently released a new product line — DuraTech™ by Microban® — as a durable, effective antimicrobial solution for cotton products. DuraTech uses an antimicrobial compound that is odorless and colorless. Though it is also water soluble, it can bind to cellulose via permanent covalent bonding, resulting in wash durability. The compound has been widely used in the cosmetics industry where it acts as a sustainable preservative to prevent the harmful build-up of bacteria in cosmetics and personal care products. The technology works by integrating into cotton fabric during the manufacturing process and penetrating bacteria, inhibiting the ability of microbes to reproduce.

Efficacy And Durability

The antimicrobial efficacy and wash durability of the DuraTech antimicrobial technology has undergone stringent validation following industry standard testing methodologies. These procedures involved testing multiple types of cotton — including 100-percent cotton knits for apparel, 100-percent woven cotton sheeting and 100-percent terry cotton fabrics — in line with the ISO 20743, JIS L 1902, and AATCC TM 100 standard testing methods. During testing, DuraTech-treated cotton underwent laundering and tumble-drying using a representative commercial detergent. Antimicrobial efficiency was tested by comparing quantities of bacteria known to cause cotton degradation on treated and untreated cotton samples, and relevant fabric properties were also measured before and after laundering.

DuraTech technology was assessed for its antimicrobial efficacy after multiple washes, following the AATCC LP1 washing protocol on various cotton materials. Fabric pH, color fastness and crocking fastness also were evaluated following AATCC TM 81, AATCC TM 61-2A, and AATCC TM 8 protocols, respectively. The reduction of odor in DuraTech-treated cotton products compared to untreated products was tested with the AATCC TM211 Drager method, providing real-time and visual depictions of ammonia levels using two ammonium-producing, odor-causing bacteria.

Seamless Incorporation Into Manufacturing

DuraTech consists of two water-soluble parts — the active compound and a catalyst — allowing for seamless mixing and incorporation into padding manufacturing processes without the need for polymer binders that can cause unexpected buildup on process rollers in the mill. Because of its water solubility and the absence of binders in its composition, DuraTech covalently bonds with the cellulose structure of cotton under certain conditions to impart long-lasting wash-resistant antimicrobial properties to the textile without impacting its physical properties.

Benefits And Applications Of Antimicrobial Cotton Technologies

The expected lifespan of cotton fabrics depends on their intended use; cotton knits for seasonal garments will undergo up to 50 wash cycles, while domestic-use items like sheeting and terry towels — which are more frequently exposed to human skin and humidity — will require more regular washing. Reported findings demonstrate that DuraTech-treated cotton maintains up to 99.99-percent bacterial inhibition after 75 wash cycles compared to untreated controls. In addition, treated samples achieve up to 99-percent odor reduction after 75 washes, without compromising on other essential fabric properties.

Microban reports that DuraTech is compliant with industry standards and regulations, compatible with sustainable manufacturing processes, and safe for handlers and users. The non-heavy metal-based formula is biodegradable, and is not an aquatic hazard according to OECD test guidelines 301A, 111, and 209.⁵ The technology is registered with the United States Environmental Protection Agency (EPA), and Microban also is pursuing textile-specific certifications for DuraTech — like Bluesign® and Oeko-Tex® — as part of an ongoing commitment to making textile manufacturing processes more sustainable.

Built-in antimicrobial technologies can be a key tool in the cotton textile industry, seamlessly integrating into the production process to extend the usable lifespan of fabrics and enhance the end-user experience.

References
1 Cotton: Industries: WWF. World Wildlife Fund. https://www.worldwildlife.org/industries/cotton.
2 Grand View Research. Global Textile Market Size & Share Report, 2022-2030. https://www.grandviewresearch.com/industry-analysis/textile-market.
3 Roy Choudhury, A. Finishes for protection against microbial, insect and UV radiation. Principles of Textile Finishing 319-382 (2017).
4 Tessier D. Surface modification of biotextiles for medical applications. Biotextiles as Medical Implants 137-156 (2013).
5 Qian, L. & Sun, G. Durable and regenerable antimicrobial textiles: Improving efficacy and
durability of biocidal functions. J Appl Polym Sci 91, 2588-2593 (2004).

Editor’s Note: Yihong Li is senior technical manager and Xiuzhu Fei is senior formulations chemist for Textiles at Microban International, Huntersville, N.C.

November/December 2022

Lab tests showed Candiani’s new Coreva stretch denim is completely biodegradable.

By Antonia Wilson

“We buried the jeans in March and they were gone in January,” CEO Alberto Candiani said of Candiani Denim’s most recent experiment.

Ten months sounds impressive, but controlled lab tests have shown the Italy-based brand’s new stretch denim, Coreva, can almost completely biodegrade in as little as six months in optimum conditions. “We tried to compost Coreva stretch jeans in our backyard and it worked,” Candiani said. “The difference between the lab test and our backyard test is that temperature and humidity are not constant in nature.” This of course means consumers could try the experiment for themselves, years down the line in their own compost bins.

Natural Rubber Component

First launched in 2020, Coreva replaces the need for petrochemical-based elastane often found in stretch denim and stretch fabrics more widely. Made using organic cotton yarns wrapped around a natural rubber core yarn — both renewable sources — the resulting fabric is plastic-free meaning it also won’t shed microplastics when washed. However, the fabric still maintains the elasticity, durability and softness expected from high-quality stretch denim. Not only does this make it fully biodegradable — able to be broken down through composting — but also more easily processed post-consumer use, with fibers separated for reuse or recycling, in part thanks to the thickness of the rubber yarn.

“At the end of life of a product it would be correct first to upcycle it, then to downcycle it and at the end to recycle it,” Candiani explained. “When you recycle a product, an old pair of jeans for example, you will be able to extract a portion of material that can be reused to spin a new yarn to make a new jeans, but the rest will inevitably be waste. Our aim is to allow that waste to return to nature with a positive impact, giving purpose to the raw materials initially extracted to make the jeans as they can now be used to grow new raw materials.”

Given that the majority of clothing globally is now made from synthetic fabrics, Candiani’s innovation has overcome a major technological challenge that could have a huge impact on the fashion industry more widely.

Circular Product

The images from the experiment speak for themselves — a dusty outline of what was once that familiar pair of jeans, with only disjointed seams and disintegrated pockets remaining. It’s a stark, but refreshing sight compared to the images saturating the media showing diggers emptying fabric waste into landfills.

The aim is to create regenerative denim goods that can be returned to the environment — to use jeans to eventually grow the cotton to make jeans. The tangible circularity of Coreva comes at a time when the need to embrace nature-based solutions in fashion and recognize biodiversity as part of the climate crisis more widely, is more urgent than ever before. While many brands talk the talk in their sustainability strategies, critics say it often remains a check-box exercise, rather than brands legitimately addressing their impacts.

Consumers are increasingly savvy, demanding transparency, traceability and tangible efforts from brands to do better; and organizations including the United Nations continue to highlight the impact of the fashion industry, not only in terms of the environmental and ethical of production, but also post-consumer waste.

“Everything I’m doing is to connect the industrial and the agricultural systems in order to neutralize impacts and, if possible, to create a final positive impact of products on the environment through regenerative properties and practices,” Candiani said. “True design means problem-solving, and fashion has to look into circularity, science and smart materials in order to engineer products — starting with solutions to the problems those same products may create at the end of their lifecycle. Ethically, this should be mandatory, but we all know that the fashion industry is still massively over-producing without caring much — the reason why we need legislation and politics to regulate the industry.”

Fully Tested

Candiani has produced an impressive selection of sustainable fabrics, with a variety of certifications, but Coreva is an industry first and was trialed in collaboration with several partners including the Rodale Institute, a non-profit organization that supports regenerative agricultural research. “Rodale was, for us, the perfect partner to test Coreva’s regenerative circularity models and systems in every specific environment where organic and regenerative agriculture take place,” Candiani noted. “The idea was to test, verify and scientifically certify effectively on and in the ground Coreva’s compostability and regenerative properties.”

Experiments on the material’s biodegradability, disintegration and ecotoxicity — a measure of a substance’s harm to animals and plants — were carried out to determine compostability, in compliance with European Union standards. However, since there is not yet a dedicated certification process for compostable fabric, the closest available category of packaging was selected. All of the criteria were met, and after 12 weeks, 98.1 percent of Coreva’s original mass had disintegrated. Mung beans and barley were grown to test soil health and conditioning capacity, with results showing significantly better growth of up to 23.5 percent. More recently, growing Candiani’s hybrid, non-GMO cotton variety, Blue seed cotton — designed to produce a stronger fiber, be more resistant in the field, and require less water and chemicals — also was successfully tested.

Although Candiani does not claim to have invented stretch denim, the brand is known to be an expert in the industry. Perfecting Coreva for production still took five years of research and development, however, refining the biogen fabric to ensure it was hard-wearing in consumer use, but biodegradable post-use. “A big challenge was the original vulcanization process of that rubber which was not allowing the elastic to be fully biodegradable, but we fixed that thanks to a very solid partner that tweaked the process and gave us a yarn which is not only bio-based but also biodegradable — and compostable,” Candiani said. The final challenge was about its performance and stability, he noted. But that was an “easy fix” — perhaps unsurprising given the brand’s heritage as a leader in its field.

Company Ethos

As a fourth-generation denim producer, Candiani is taking strides to innovate both the family company and the industry, and his vision to uphold heritage while embracing change follows his globally minded father. Candiani talks about sustainability as a mission based on location rather than a journey. In operation since 1938, the company’s mill in the town of Robecchetto con Induno, Italy, sits between Milan and the Alps. Since 1974, it has been located at the heart of a nature reserve called Parco Del Ticino, running alongside the River Ticino, with a hugely diverse ecosystem. Despite being Europe’s largest denim mill, with two plants covering 85,000 square meters of production, it has been dubbed the “greenest mill in the blue world” with much stricter local environmental regulations than other denim mills, Candiani reported, which the brand has fully embraced.

“No other large textile operation in the world is located inside a nature reserve,” Candiani said. “The national reserve was founded decades after the mill was originally started so we found ourselves all of a sudden surrounded by it. Being immersed inside such a delicate environment that required special attention and care made us think and act differently in terms of production and productivity, challenging us to come up with our own best practices in order to reduce our impact on nature.”

The brand has now developed a full Coreva collection, including shirts and pants in various fits and colors. British designer Stella McCartney and Dutch jeansmakers Denham are among the first brands beyond Candiani to use Coreva in their own collections. Candiani acknowledges that it may not be a swift transition across the entire industry, given that Coreva can cost 30- to 50-percent more than conventional man-made stretch denim. He remains confident, however, as Coreva outperforms synthetics in terms of elasticity, recovery and comfort, according to Candiani. The aim is to have all Candiani stretch denim made with Coreva by 2030. Alongside this, the brand will use regeneratively grown cotton in at least 50 percent of the entire production of its denim by next year.

Given the growing body of research showing the devastating pace of biodiversity loss and its link with climate change, a move towards regenerative agriculture is something more brands need to engage with. Regenerative agriculture involves a holistic, natural approach to farming, prioritizing long-term value over short-term gain. For instance, practices such as crop rotation, natural grazing patterns, avoiding chemical pesticides and planting native trees or creating wetlands to boost biodiversity. This approach not only reverses soil erosion, which helps ecosystems become more resilient against droughts, desertification and wildfires, but it can also improve the health of the soil, which allows it to absorb a greater amount of carbon from the atmosphere. And sequestering carbon, particularly through soil, is, arguably, the biggest nature-based solution to climate change. It’s not only a means to future-proof the land, but future-proof a business as well.

Candiani will no doubt continue to disrupt, innovate and reinvent — but, what could the future of fashion look like in a dream world of circularity? “Edible fabrics,” Candiani noted. “I can’t promise you yet that in the future we’ll be able to eat our jeans at the end of their lifecycle instead of throwing them away. What I can tell you for sure, is that we have already made it possible to link industrial denim production to regenerative agriculture by creating edibles, such as veggies, using old jeans as soil conditioner.”

Editor’s Note: Antonia Wilson is a freelance writer and editor.

November/December 2022

Comez offers a variety of machines that are suitable for producing highly technical medical applications.

By Fulvio Festari

Italy-based Comez International S.r.l. — a member of the Jakob Müller Group, Switzerland — specializes in engineering and manufacturing crochet and warp knitting machines. Its products are used worldwide for narrow fabric production including lace and ribbons for outerwear and lingerie accessories. However, increasing demand for technical textiles prompted Comez to develop specific solutions for highly technical applications as well.

Knit fabrics are widely used in various surgical applications and textile implants including suture materials, hernia meshes, artificial ligaments and knitted grafts, for example. The versatility of Comez knitting machinery enables its customers to design a variety of textiles that meet required specifications in terms of strength, flexibility, durability and stability for medical textiles.

Hernia Mesh

Many manufacturers choose Comez machines for hernia mesh production with customized knitted designs and a wide range of pore configurations. The mesh may be used to treat abdominal or inguinal hernias. Comez provides solutions for these knitted textile implants — such as the ACOTRONIC 8B/600 and the SNB/EL-800 machines — which are perfectly adapted to their area of use for permanent patient support. Both 2D and 3D meshes can be produced using monofilament or other materials.

Textile Ligaments

Textile ligaments, used for the reconstruction of damaged ligaments, are another innovative application that can be designed using Comez advanced knitting technology such as the ACOTRONIC 8B/600. These articles require a special texture that can be created using crochet knitting machines. The layout of the finished product — as well as its dimension — can vary according to individual requirements and surgical treatments.

Blood Filtration Fabric

Artificial lungs, blood oxygenators and heat exchangers can be based on textile products. All these solutions contain membrane fabrics consisting of microcapillaries linked by crochet knitting technology. Comez designed a solution for the production of blood filtration fabrics, a special configuration of the CT-8B/829 model.

Knitted Vein And Artery Grafts

Specific warp and crochet knitted textile vascular grafts are also used during cardiovascular surgery to replace damaged or malfunctioning arteries and veins. These grafts are made using man-made materials and are produced in different designs and diameters featuring linear and bifurcated structures. The Comez DNB/EL-32 model permits the construction of such graft materials.

Comez provides a full scope of services including consultancy, joint developments with regards to new solutions, and customized machine configurations for surgical and technical applications.

Editor’s Note: Fulvio Festari is product manager at Italy-based Comez International S.r.l.

November/December