Sustainable solutions in antimicrobials

July 24th, 2017 / By: / Featured

With environmental concerns about traditional treatments, the industry works to offer more eco-friendly options.

Antimicrobial properties are fast becoming an expected treatment in textiles for applications that range from hospital drapes and linen, to contract and domestic textiles, as well as clothing. While offering protection from germs is a positive, there has been some disquiet concerning the environmental impact of antimicrobial treatments.

In response, fiber and fabric manufacturers are quietly working at finding more sustainable solutions, and the resulting innovations are now starting to become available on the market.

Water pollution

Water pollution is one of the primary concerns with antimicrobial treatments that rely on silver as their active ingredient. Researchers and manufacturers are looking at ways to avoid this through the production process and find alternatives that do not compromise performance.

The Canadian manufacturer Filspec™ has developed two alternatives approaches to antimicrobial treatments: Pearlite™ Rayon and RecoveryFil™. Pearlite Rayon takes its active ingredient from the inside of oyster shells that would normally go straight to the landfill. A pearl viscose offers antimicrobial properties alongside moisture absorption and a soft handle, suitable particularly for sports clothing such as socks.

RecoveryFil uses zinc oxide (ZnO) as an alternative to silver as the active ingredient. It is combined with a Tencel/Lyocell viscose and additional viscose that has been embedded with fine-powdered shell from mother-of-pearl that offers protection from UV rays. The result is a fabric that provides anti-bacterial and SPF 50 sun protection with a soft handle, which makes it well suited for clothing and intimate apparel.

Filspec’s RecoveryFil utilises zinc oxide as an alternative to silver for antimicrobial treatments. Photo: Filspec™.

Researchers at a group of universities headed by Linköping University in Sweden are looking to extend the use of ZnO for smart textiles. In their research and development ZnO is grown on the surface of the textile using a simple aqueous chemical growth method. Initial results indicate strong antimicrobial properties and promising responses as a sensor.

In the Slovak Republic, Chemosvit Fibrochem a.s. has been producing fibers for 75 years and since 1974 specializing in polypropylene under the trade name PROLEN® YARN. Yarn qualities include flame retardancy, moisture management and antibacterial properties.

The company prides itself on combining technical innovation with strong sustainable credentials. It has been ISO 9001 certified since 1996, and has since received a number of certification standards, including Oeko-tex Standard 100, and it has become a bluesign® system partner.

New developments have to align to these standards, and the company’s antibacterial yarn is no exception. Prolen Bodyfresh and Prolen Siltex are both multifilament yarns that incorporate biogesic silver ions to inhibit the growth of bacteria, reducing odor and helping to maintain the skin’s freshness. The active agent is incorporated into a hollow fiber to prevent migration during the laundry process into waterways. In retaining the active ingredient for longer, the lifespan of the product is also extended.

Long life

Extending the lifetime of fabrics is a key strategy in creating strong environmental credentials. For most fabrics this involves wear and laundry testing, but antimicrobial materials have additional performance criteria to meet and have to be shown to be effective, particularly through wash cycles.

Longevity without compromising safety is a focus of the See It SAFE® range of reusable anti-bacterial woven fabrics from Toray Textiles Europe Ltd. The company use X-Static silver fiber where the silver is permanently bonded to the surface of the fiber that can last the lifetime of the woven fabric. The electron release of the silver happens when the bacterial attracts the metal that then breaks through its wall disrupting the DNA by binding with ammonia, denaturing proteins and neutralizing odor.

Meeting environmental standards is a core concern with Nilit Ltd., headquartered in Israel. Focusing in performance fibers, all of its polymers meet the Oeko-Tex Standard 100 demonstrating that they carry no health risk. The company’s Bodyfresh fiber is designed to perform well and be kind to the environment. Antibacterial properties are combined with a soft handle to provide the wearer with freshness and comfort during workouts and sports activities. The antibacterial treatment is embedded within the microfiber to make it more resilient to wear and laundering. In testing performed by the Hohenstein Institute, the fiber was shown to retain its level of odor-reducing capability through fifty wash cycles.

When less is more

Using less product is ultimately better for the environment as there is less weight in shipping, fewer launderings, and smaller mass at the end of life. Two production processes that are helping to achieve this are highly engineered yarns and nanotechnology.

Teijin’s Mightytop® II Eco and Filcare yarns are polyester yarns engineered to have a hollow core. Mightytop carries anti-bacterial and deodorizing characteristics and helps to prevent dust mites. Filcare is also antibacterial with a ‘Y’ shaped internal structure and a silicone coating. Both are used in bedding products.

One of the many benefits of nanotechnology as a coating treatment is that it reduces the amount of product needed, offering economic and environmental savings. As a relatively young technology, standards can vary enormously. In Taiwan the Industry Development Bureau, Ministry of Economic Affairs have developed a nanoMark certification with the Taiwan Nanotechnology Industry Development Association (TANIDA) that’s responsible for the verification system.

Everest Textile Co. Ltd.is one of the companies that has received accreditation in the production of antibacterial textiles. Their Nano Silver yarn has undergone testing for cell and oral toxicity, skin irritation and performance after dyeing and finishing. In AATCC100 tests involving 100 washes, the material was found to retain 99 percent of its antibacterial effectiveness. The association has a large number of standards compiled including the TN-024 V+V specifically for nanosilver and antibacterial textiles.

New opportunity

Environmental concerns around traditional antimicrobial processes have forced researchers and manufacturers to seek creative solutions to the problem. What is emerging are new developments in manufacturing process that use less material and in more economical ways, coupled with the introduction of novel alternatives. All of these indicate that problems can also be opportunities.

Marie O’Mahony is an industry consultant, author and academic. She the author of several books on advanced and smart textiles published by Thames and Hudson and Visiting Professor at the Royal College of Art (RCA), London.