Antimicrobials To The Rescue

By Ellen Wuagneux, Associate Editor | June 10, 2009

additives boost the power of nonwovens to fight off germs, bacteria and odors

With the threat of the swine flu pandemic just beginning to wind down as we went to press this month, it seems as fitting a time as ever to consider the advantages antimicrobial treatments have to offer nonwoven products. Whether they are incorporated at the fiber/polymer or finished product stage through extrusion or injection molding technologies, these additives provide benefits ranging from odor/stain elimination and protection against deterioration to anti-fungal and anti-bacterial properties. Target areas include healthcare, filtration, automotive, home furnishing, food service, packaging and more.

    Recent public health scares over drug-resistant bacteria and growing concern over the spread of germs and infectious diseases have only boosted consumer awareness of the importance of antibacterial and antimicrobial products. These changes are keeping manufacturers on their toes across the supply chain as they answer the call for more protection at a lower price. “Market requirements continue to evolve as consumer awareness increases,” observed Mimi Cartee, global alliance manager at Huntsman International. “Con­sumers today are more knowledgeable than they were five years ago, mainly because more information is available at our fingertips.”

    W. Curtis White, CEO and director of R&D at Aegis Environments, agreed and stressed the importance of providing nonwovens that are not amplification or transfer sites for the growth of microbes. “The almost daily press reports of microbes impacting our lives in negative ways is really fueling this trend,” he said. “The public’s recognition of how microbes impact their quality of life seems to grow daily. It's hard to go a week without at least one front page news story about the need to control microorganisms.” In Mr. White’s opinion, public recognition may be boosting awareness of antimicrobials but what will drive sustainable, long-term growth is using environmentally friendly products that meet consumer expectations.

    Elevated interest from the market is the impetus for companies like Agion to develop new technologies with antimicrobial protection as well as other benefits. “We are seeing an upturn in demand for antimicrobials and an increase in awareness and applications that antimicrobials are perfect for—water filtration, medical textiles and nonwoven applications for consumer and food service environments,” reported Cyndy Hunter, Agion’s director of marketing.

    That said, Ms. Hunter warned that education about the benefits of antimicrobials needs to continue, especially at the consumer level where knowledge of the true benefits of this technology is still quite low. “Companies who are innovators and understand the marketing impact of having this feature will drive the market,” she predicted.

Strides Toward Sustainability

As is the case in virtually every corner of the nonwovens industry and all aspects of manufacturing, environmental friendliness is a quickly growing consideration for both producers of antimicrobial treatments and end product customers. While keeping costs down remains a key priority, it’s now clearly the case that the more sustainable an antimicrobial product is, the better. “One of the new drivers for consumers is sustainability—products that have a reduced footprint,” stated Ms. Cartee of Huntsman. “However, these products will still need to be affordable. Consumers aren’t going to pay more for sustainability but expect it from their products.”

    Aegis’ Mr. White pointed to the expanding power of green thinking. “The ecologically sound or ‘green’ movement is not just chugging along, it’s gone supersonic,” he said. “End customers don’t just want microbes controlled—they want them controlled in the most environmentally responsible way possible.”

    These demands are moving nonwovens producers away from risky chemical additives and are encouraging suppliers of antimicrobials to put cost-effective, earth friendly and safer elements at the forefront of their antimicrobial innovations.

    With its natural silver-ion-based technology, Agion has taken a green approach by achieving Cradle-To-Cradle certification, which recognizes its use of environmentally safe materials and conservation of energy and water. “We have based our entire position on the concept of ‘green,’” explained Ms. Hunter. “Agion is the first antimicrobial technology to be third-party certified for its environmental intelligence.” The process involves encapsulating the silver in a zeolite (almost like a cage) that allows the silver exchange to happen in a controlled release. The technology can be incorporated in a fiber or finishing step with binder for textiles or directly into polymers or as a coating on different materials.

    Other recent efforts at Agion have centered on a new tri-functional technology scheduled for launch in the second quarter that incorporates the Agion antimicrobial and a brand new odor elimination technology as well as a verification technology that en­ables users to confirm that Agion antimicrobials are present in the material. This is useful for manufacturing quality control and as an anti-counterfeiting measure.

    Americhem also uses silver to boost the power of its antimicrobial products. A global provider of custom color and additive solutions for synthetic fibers and polymer-based products, the company recently rolled out a full line of antimicrobial masterbatches for synthetic fiber applications. The products allow customers to achieve increased efficiencies and produce superior end products.

    “The high concentration of silver in antimicrobial masterbatches provides cost-effective inhibitory activity against a range of micro-organisms including bacteria and fungi, among others,” stated Roger Threadgill, technology manager at Americhem. The company’s new antimicrobials offer improved performance to an array of markets and end product applications including sports and performance apparel, health and homecare textiles (bedding and mattresses, upholstery, respiratory masks and uniforms), carpets and flooring, shoes, filters and artificial turf.

    According to the company, the new line of antimicrobial masterbatches addresses one of the main challenges with melt spun antimicrobial additives, which is achieving dispersion quality suitable for fine denier applications and lower abrasion. They boast significant improvements in dispersion, lower abrasion and higher efficacy. These products are intended for use in fine denier polyester, nylon and polypropylene fibers.  

Many Ways To Be Green

For its part, Huntsman gears its silver and triclosan-based antimicrobials specifically toward durable nonwoven applications in medical, home furnishings and industrial segments. The company’s newest offering is a silver chloride antimicrobial featuring excellent efficacy against both Gram-positive and Gram-negative bacteria at low usage levels. The product can be used on durable or non-durable products with no impact on other performance features such as repellency, moisture control, etc.

    Huntsman’s use of natural materials is part of a three-pronged sustainability initiative—using renewable feedstocks, helping customers conserve and using less energy and water. “These sustainability guidelines are built into our innovation process so that every new product launched provides a benefit to the environment,” Ms. Cartee said. She went on to clarify that the term “green” can have many definitions. “Being green means that products are produced in a way that minimizes waste and eliminates or reduces harmful raw materials. However, it can also mean extending the life of a product so that it can be re-used or recycled, thereby reducing the overall footprint.

    On the European front, companies such as Italian supplier Viba Group are also touting the benefits of silver. Offering antimicrobial masterbatches containing both organic and inorganic additives de­pending on final application, the company supplies grades for both extrusion and injection molding. “Our special grades of additives based on silver ionium perform a more controlled migration compared to traditional offerings,” opined Grazia Iannacito, director of R&D, additives at Viba Group. “The end product, therefore, is much more protected and there is a very low risk of yellowing.”

    While the marketing advantages of offering natural-based antimicrobials are obvious, Ms. Iannacito said that there are drawbacks as well. “Much research is continuously carried out on antimicrobials of natural origin, especially for food packaging applications. For a masterbatch producer, the problem is that these substances very often are sensitive to high temperatures, and therefore cannot be processed.”

    Aegis Environments puts a different spin on what it means to be “green” by offering antimicrobials that permanently bond to the treated good and therefore do not leach into areas (skin, waste water, etc.) where they are not intended to go. “This is a critical part of any green story a nonwoven product is trying to tell,” ex­plained Mr. White. “The last thing you want to do is use an antimicrobial that is worse for the environment than the microbes it is controlling. Antimicrobial technologies that leach into the surrounding environment impact more than the nonwoven they are supposed to be protecting.”

    The company targets the wipes, filtration media and fiberfill markets with its line of bonded antimicrobials designed to work well on virtually all substrates with a safety profile and range of antibacterial and antifungal performance that suits them to myriad nonwoven end uses from consumer and commercial to medical. Aegis has also recently rolled out its Ecofresh trade name program for its antimicrobial technology, which is designed to help nonwoven products communicate to the consumer that they are using a responsible antimicrobial designed for high quality protection with a light environmental footprint.

Taking Tests To Tasks

High on the list of challenges faced by producers of antimicrobial treatments for nonwovens are government regulations, both in the U.S. and Europe. While most suppliers are finding ways to work within these constraints, they describe testing, registration and labeling requirements as formidable hurdles to jump.

    In the U.S., antimicrobial treatments fall under EPA regulations for pesticides under the statutory authority of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). While FIFRA requires the registration of any substance intended to prevent, destroy, repel or mitigate pests, the Code of Federal Regulations offers an exemption for an article or a substance treated with or containing a pesticide to protect the article or substance itself if the pesticide is registered for such use.

    EPA requires special tests to ensure efficacy of public health pesticides when the pests are invisible disease-causing microbes, rather than insects or rodents that may be harboring disease organisms. EPA rules that determining human and ecological risks from exposure to antimicrobial pesticides requires different types of measurements and models than those needed for pesticides largely applied to crops and other plants. For this reason, regulations governing pesticide registration requirements also incorporate special antimicrobial sections.

    “Regulations, such as those from EPA in the U.S. or BPD in the EU, will limit the number of new products that can be launched into the market,” predicted Huntsman’s Mr. Cartee. “Suppliers will need to find creative ways of working with existing products or be willing to invest significant money into regulatory testing.”

    From the point of view Agion’s Ms. Hunter, these regulations are making it hard for producers to communicate the products’ benefits to the end user and stay within guidelines of language. “It is difficult to explain all of the benefits derived from use and stay within what is deemed appropriate by the governing bodies,” she said. “In addition, there are many different types of solutions in the market that can become confusing to a prospective company considering adding this feature.”                

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