By Melissa Donovan
The November issue of Digital Output discussed antimicrobial coated fabric, defining what it was, what it is made of, where it is being used, and whether it has staying power. While COVID-19 rages on, it’s no surprise that graphics need a little extra protection these days. A second layer of defense to combat infection is helpful even after the appropriate hand washing, social distancing, and mask wearing measures are taken. This is when antimicrobial coated films and laminates step in.
These materials are instrumental in slowing the spread or in some cases eliminating bacteria in high-touch, high-traffic areas. Think transit, hospitals, and grocery stories. The added layer of protection provides some peace of mind to retail workers and consumers, office-goers, and anyone truly out and about in public.
Above: Drytac Protac AMP Film is a 6-mil textured polyester surface protection film that incorporates Microban antimicrobial protection.
Antimicrobial, antibacterial, and antiviral coated film or laminates prevent bacterial and fungal build up, eliminate odor causing bacteria, and kill or slow the spread of viruses depending on the term.
“We define an antimicrobial laminate as a film that is intended to be overlaid onto a surface or print and can kill or slow the growth of micro-organisms like bacteria, virus, or fungi,” shares Austin Eck, product manager, FDC Graphic Films, Inc.
Ross Burnham, senior marketing manager, Mactac, explains that “antimicrobial films can be applied to surfaces to inhibit microbes’ growth, which can cause odors and stains. These films can continuously kill microbial containments and resist microbe growth on the film’s surface, providing a built-in protection without releasing toxic substances into the environment. Technologies are available to have the biocide either top coated or embedded into the film or laminate.”
Confusing or interchanging the term antimicrobial and antibacterial happens a lot, but it’s important to realize there are differences based on the chemistry of the product, says Steve Yarbrough, product support specialist, Drytac. “Antibacterial films will protect against harmful bacteria such as E.coli and MRSA, while antimicrobial films are effective against these bacteria, plus fungi including mold, algae, and mildew.”
It’s also important to note that a lot of the materials with antimicrobial coating also offer features like protecting printed images from abrasion and offering UV light protection when used as an overlaminate, adds Burnham.
The Science of Antimicrobial
Silver, copper, and zinc are known for their ability to eliminate or disrupt the growth of viruses and bacteria. These are commonly found in antimicrobial coatings.
The chemical composition of coatings varies based on the company engineering the product and its proprietary process. “Antimicrobial film technology has been long documented utilizing elements including silver, copper, and zinc. Proprietary characteristics tie into how the ions of these elements bond to their applied compounds,” explains Burnham.
For example, Drytac’s proprietary materials utilize Microban ZPTech additive technology. It incorporates zinc pyrithone throughout a scratch-resistant hard coating applied on base polyester film. It is approved in Europe and the U.S. for use in treated articles.
“When microbes meet the Microban reservoirs in the film, the cell wall of the microbes is disrupted. The cell wall protects cells, which is needed in the process of mitosis—cell division—in order to replicate. The cell wall is disrupted prior to contact. This limits the ability of the microbe to spread by providing constant protection against the spread of microbial contamination. With this disruption of the biological functions of the bacteria, it cannot reproduce or proliferate,” explains Yarbrough.
Silver is probably the most common ingredient found in an antimicrobial coating. “Different proprietary systems work in similar manners. Antimicrobial laminates often contain ionized silver particles that disrupt the metabolism of these micro-organisms and slows their growth,” adds Eck.
Zinc is another substantially helpful substance. “Zinc-based additives are broad spectrum antimicrobials, making them effective against many micro-organisms including bacteria and fungi,” notes Yarbrough.
The ions in copper prevent cell respiration and damage the bacterial cell membrane or viral coat to destroy it, he adds.
When it comes to any engineered coating, it’s important to address whether there are any health or environmental concerns. The common ingredients—silver, zinc, and copper—found in antimicrobial coatings in particular are not harmful when used appropriately.
The additives used in an antimicrobial coating are generally harmless, but it really depends on the additive. For example, Rebecca Fuhrman, market development manager of coated films, Tekra, says there are no health concerns when an additive is used that is made up of silver nanoparticles.
Consider the substrate as well, especially in regards to recycling. “Materials are commonly PVC-based film with a pressure-sensitive adhesive and release liner. Like other PVC print media, ink, and overlaminate combinations, we recommend the customer work with local recyclers to understand available options,” suggests Burnham. Mactac’s antimicrobial films provide no health concerns for the recommended applications in the print and surface protection market, according to the company.
To ensure harmful ingredients are added during the production and coating processes, print service providers (PSPs) may want to check if the coating is registered with the EPA, BPR, or other global regulatory organizations for use in treated articles, suggests Yarbrough. Microban ZPTech is registered with these and by design, the coating is permanently locked into the hard coat and cannot leach or migrate from the film.
Standards to Live By
Standards and certifications are helpful to ensure a coating and/or material isn’t harmful to the environment or human health. They are also useful to confirm that the coating is approved for use as antimicrobial.
“The EPA offers testing at various levels, which allows the material to be registered. There are also several independent labs that can test the effectiveness, but do not offer certification,” recommends Fuhrman.
A standard that Eck finds helpful for PSPs to refer to is the International Organization for Standardization (ISO) standard for the measurement of antimicrobial activity on plastics and other non-porous surfaces. “A product carrying a standard similar is a definitive advantage over a product that does not. Users should check the technical documents that accompany the film. Respectable products will indicate their efficacy against different micro-organisms.”
Yarbrough notes that it is important to verify what the material is rated for with the manufacturer. “Anyone claiming that their product protects against any named disease needs to have that product registered with government agencies, certified within global legislation, and comply with localized testing requirements.”
“Print providers should look at products that are third-party certified for the claims made by the manufacturer,” recommends Burnham. An example is ISO 22196, which is the specific standard for evaluating the antibacterial activity of antibacterial treated plastics and other non-porous surfaces.
Digitally printed graphics are helpful for wayfinding and conveying important safety instructions. It is no surprise that antimicrobial films and laminates are used to protect high-touch applications in high-traffic environments.
For laminates, popular applications include tabletops, doorknobs, countertops, mass transit applications, or any surface that is going to be touched frequently between cleanings. “These applications are ideal for an antimicrobial laminate because there is a high risk for surface contamination and transmission of micro-organisms. A product that slows growth may reduce the likelihood of transmission,” suggests Eck.
“Any high-traffic or high-contact area benefits from a protective film such as kiosks. High-contact areas with the protective film would limit the production of microbes by disrupting their cell wall. This disruption will lessen the exposure to said microbe hence lowering the spread and transmission of contamination,” explains Yarbrough.
Fuhrman says main applications seen in the market today are customer touch points in retail or any public spaces, as well as touch panel overlays.
Many of the aforementioned examples are areas that Burnham classifies as high-touch points. “Antimicrobial films and laminates are growing in use in hotels, restaurants, schools, offices, and medical clinics. This includes applications for counters, touch screens, door handles, push bars, desks, and tabletops.”
With the recent pandemic, film and laminates coated with antimicrobial features are in high demand. The immediate future calls for a heightened need of these products, but is the need sustainable? Antimicrobial materials are not going to disappear, customers may even prefer this media over one that doesn’t feature antimicrobial properties.
Eck says that the pandemic is changing the way people think about how they interact with each other and public surfaces. “The heightened awareness of the cleanliness of a surface is going to cause customers to lean toward purchasing an antimicrobial laminate for any number of applications that will be in highly touched areas, including door knobs, points of purchase, lavatories, and mass transit.”
“It is now more recognized that surfaces can transmit bacteria, so it is important that all spaces have infection control procedures in place. Offering films that can stop the transmission of germs and organisms and improve public health is a market which is here to stay,” agrees Yarbrough.
Film products with antimicrobial characteristics have been available for years, according to Burnham. However, the pandemic has renewed interest, in addition making the products more of a standard for keeping certain environments clean. “Facility owners in the hospitality, education, retail, entertainment, and medical industry look to offer additional protection for their customers and patrons.”
Fuhrman notes that health and safety are not exclusive to the pandemic. “Doing what we can to help reduce the growth and protect the surfaces we touch daily is a practice I think we can all get behind.”
Made to Last
A takeaway from both vendors of film and laminate as well as fabric coated with antimicrobial properties is that even when COVID-19 is under control, heightened awareness of touching things and transmitting viruses or bacteria will remain.
As such, it seems prudent for print providers to become aware of the various products available designed to combat or slow the growth of micro-organism transmission and familiarize themselves with them.
Dec2020, Digital Output