Antimicrobials Save The Day

By Sandra Levy, Associate Editor | June 2, 2010

Fighting germs, bacteria and odors is a no-brainer for nonwovens producers thanks to a barrage of antimicrobial treatments.

If you’ve ever wondered if the wipe that the clerk at your favorite fast food restaurant used to clean the spill on the counter is loaded with bacteria that may be passed to your food, you are not alone. If you’ve worried that a loved one may pick up a hospital-acquired infection from touching a cubicle curtain, you’re not being paranoid. And, if the thought crossed your mind that the upholstery in the trunk of your car may be teaming with bacteria, it probably is.
As the use of nonwovens continues to prevail in myriad applications, companies that specialize in antimicrobial treatments are coming to the rescue with a host of innovative treatments to keep bacteria, mold, mildew and odor at bay in these scenarios and many others.

More Education Needed     

While the use of antimicrobials in nonwovens appears to be on the upswing, experts agree that more consumer education is needed.

 “There is a growing awareness of antimicrobials. The medical community understands it. They all have their own staff trying to understand that because the hospital-acquired infection rates are growing at an alarming rate and are being scrutinized by federal and state governments. It’s very costly to hospitals to have extended stays for people who acquire an infection in the hospital. They understand the economics of it and it makes sense to try to eliminate that. The fear of infections and fear of further hospitalization has made the whole medical arena thirsty for something that is simple, easy, inexpensive and can combat the growth of bacteria and microbes. The military is very interested in it for the protection of soldiers,” said David Rowell, Foss Manufacturing Company’s executive vice president.

While consumers are concerned about pandemics such as MRSA, swine flu and bird flu from coming into their homes and schools, they don’t understand antimicrobials, said Mr. Rowell. “They think antimicrobials are probably good for you but as far as understanding the technology and where the value is, I’m not so sure it’s there yet.  The momentum is growing for sure. We’ll get there,” he said.  

Jeff Trogolo, Agion’s chief technology officer said , “Education is important. There’s some misinformation about antimicrobials in general. All antimicrobials are lumped into one group. There are different techniques that have different characteristics. The consumer can benefit from understanding more about the particular technology in a product. A lot of products, especially apparel, have tags that say ‘antimicrobial,’ but consumers don’t know what it is, what the technology is, how much was used, why the manufacturers are putting it on there. One of the reasons we’re a branded ingredient is that we want people to go to our web site and learn about our product.”

With consumer awareness of microbes at a historical high, the time is ripe for education about antimicrobials. W. Curtis White, CEO, director of research and development at Aegis Environmental believes that companies using the antimicrobials on their products should do more to educate consumers. While the medical community is proactive when it comes to educating its personnel, Mr. White said, “Those who are using our materials haven’t done a good job of educating the public.” Mr. White believes the time is right to launch education as consumer sensitivity and awareness to microbial problems and the risk microbes make in their lives and goods is very high.

While it’s anyone’s guess whether more companies using antimicrobials in their nonwovens products will step up to the plate and launch consumer educational initiatives, one thing is certain: The use of antimicrobials in nonwovens is growing.

David Koehl, Lonza Inc.’s manager of commercial development, hygiene said,“This is primarily driven by consumers increasing awareness and benefits of good hygiene.  Additionally, the need for convenience has allowed wipes to begin  displacing traditional “spray and wipe” methods.  More recently, the global H1N1 pandemic produced a heightened awareness among consumers, both in the U.S. and around the world, of the need for effective and convenient antimicrobial products. There is a strong push in healthcare markets to provide efficacy against Clostridium difficile (C. diff) spores with low corrosion, low odor and cost-effective formulations.  Additionally, it appears that the industry is trending away from antimicrobial wipes containing volatile organic compounds (VOCs) due to more stringent air pollution regulations.”  

Copper and Silver

One company delivering a hot idea in the antimicrobial arena to help nonwovens producers differentiate themselves from the pack is Foss Manufacturing Company.  The company offers Fosshield, a patented technology that puts copper and silver ions into the meltstream of polyester fiber. “It’s a bicomponent fiber. We put the antimicrobial agent in the sheath of the fiber in the beginning stage when we make the individual fibers out of pellets,” said Mr. Rowell.

Applications for Fosshield include towels, mattress pads, soaker pads for mattresses, blankets, sheets, pillow cases, nurse’s uniforms, doctor’s lab coats, diabetic and compression socks, hospital cubicle curtains, face masks, athletic footwear, protective vests for the military, indoor-outdoor furniture and awnings.

The copper technology attacks the cell membrane of a bacteria, which is comprised of a high concentration of sulfur.  “Copper and sulfur have an affinity to exchange with each other. With the copper coming in contact with the sulfur, there’s an ionic exchange. Sulfur, which is part of the cell membrane is basically decomposing and compromising that membrane,” Mr. Rowell explained.

Noting that silver is an even more effective antimicrobial than copper, Mr. Rowell explained that copper and silver have a synergistic effect that speeds the delivery of the antimicrobial action.  Copper is also a highly effective antimicrobial against mold and mildew.

Fosshield inhibits the growth of  bacteria within the first 10 or 15 minutes of its exposure to bacteria. “It happens so quickly that the bacteria and microbes cannot change their DNA and mutate around the product itself. The high rate of efficacy and speed of the kill rate is very important,”said Mr. Rowell.

Another benefit of Fosshield is that it offers protection for the life of the fabric. “It’s not a topical coating that gets washed away or worn away. Fosshield was tested in 50 commercial launderings and had the same amount of efficacy as it did in the very beginning,” said Mr. Rowell.

Going After Mold

Goulston Technologies, Inc. is making inroads with an antimicrobial additive called Lurol AM-7 for fibers which are used as filling materials in pillows, quilts and jackets. “AM-7 treated fibers are also used to produce nonwoven fabrics. It is based on Aegis AEM-5772 molecule. Lurol AM-7 is an aqueous dispersion of AEM-5772.  Lurol AM-7 is a methanol-free version of AEM-5772 and is easy to handle,” said Srinivasan Ranganathan (“Ranga”) Goulston’s technical director.

According to Mr. Ranganathan, increased consumer awareness about the need for bacteria, fungus and mold control has translated into interest in antimicrobial-treated nonwoven fabrics for applications such as home furnishings, automotives, outdoor sports apparel, shoes, building materials, undergarments and healthcare.         

 “There is increased focus on the durability of antimicrobial treatments in wear and durability when washed since many of the fabrics are used for non-disposable type end uses,” he said.
Lurol AM-7 provides protection against bacteria and prevents the growth of mold in high moisture, high humidity environments and can be applied to bathroom furnishings.  

Combining comfort properties such as moisture management with antimicrobial treatments is a trend that is gaining strength.

In response, Goulston offers a moisture management treatment called Lurol PS-L366 that can be used with Lurol AM-7. “PS-L366 wicks away moisture from the body providing comfort while Lurol AM-7 provides odor control. This is useful not only in sports apparel but also in home furnishings such as bedspreads and pillow covers,”said Mr. Ranganathan.

Chemical Bonds

Another experienced player offering antimicrobials for nonwovens is Aegis. Marketed under the brand names Aegis Microbe Shield and EcoFresh, the antimicrobial product uses silane, which is a chemical bonding agent.  

“In the processing of the fiber or the processing of the final finished goods, we can add our material by spray, padding or exhaust. Our material chemically bonds just like the chemical bonds that make up the fiber and become part of the surface of the material. When microbes contact that surface, their membranes are ruptured and the organism dies. This killing field that gets laid down by this polymer formation allows for the interruption of the life processes—the membrane of the cell,” said Mr. White.

Microbe Shield and EcoFresh are targeted to sporting goods and nonwovens fillers for sleeping bags, clean room garments, hospital linens, wound care wraps, surgical drapes, covers, towels, wipes, masks, air filters in buildings and homes, upholstery material in auto headliners, backing for carpeting and upholstery, trunk roofing, wallboard, mops, sponges and commercial wipes.
Emphasizing that nonwovens substrates create a microbial habitat which can be devastating to the quality of products in a food processing plant, cleanroom or the electronics industry, Mr. White said antimicrobial contamination from a person’s skin can get into products in the workplace and can affect the quality of those products.  

Nonwovens that are used in garments, protective clothing, wipes and wraps can also be habitats for microbes. “Having safe and broad spectrum performance criteria without the risk of creating adapted microbes is another challenge when you are killing microbes. You can also produce a situation where microbes become resistant to your chemical.  Aegis’s technology avoids the potential for adaptation and resistance of microbes,” said Mr. White.

Antimicrobials are becoming increasingly important in nonwovens in the commercial market, especially in construction products and geotextiles for roadbeds.  “There’s mold and mildew and some degree of bacteria that can grow in that environment,” said Mr. White.
In the consumer arena, Aegis’s EcoFresh can be applied to towels and sleeping bags. “We’ve done surveys that show that towels last longer if consumers wash their towels less.  If consumers’ habits can be altered with the benefit of antimicrobial technology and if the technologies are safe and effective, you are adding to ecofriendliness. We use the brand name EcoFresh because freshness is what consumers want. People who buy sleeping bags are ecologically conscious and homeowners are ecologically conscious and they will make decisions based on things that are good for the environment,” said Mr. White.

Trapping Odors  

Agion is forging ahead in the antimicrobial world with Agion Antimicrobial, a technology that uses the mineral zeolite.

Applications include medical devices, water filtration, hospitality and bedding (mattress pads).
Mr. Trogolo explained that Agion uses a particular zeolite, which is very good at controlling the delivery of silver to the surface of the treated material. “We have a number of different grades and functionalities that we can incorporate into the material. We can use it to control the bacteria on the surface of the fabric.”

The company also offers Agion Active, which combines the silver antimicrobial with an odor trapping technology to prevent odors, in apparel applications. “It’s porous and has a lot of holes in it.  The silver is ionically bonded to the holes. Unlike a lot of silver technologies, ours is not in the form of metallic silver or a silver compound that dissolves. It’s bound ionically which is the form that works on bacteria. It’s in the ionic state and is delivered as an ion to control the organism on the surface,” said Mr. Trogolo.

Mr. Trogolo went on to explain that the company’s antimicrobial offers a controlled release of silver.  “It delivers silver up to a certain equilibrium concentration and then shuts off. If it is too low, it won’t be effective, if it’s too high, you will use up the silver and will not have a long lifetime,” said Mr. Trogolo. Agion Active’s technology can go into the fiber as it is being produced or it can be applied as a topical finish to an already manufactured fabric.

Emphasizing that bacteria that cause odor on the skin can get onto apparel and generate odor causing compounds, Mr. Trogolo said, “The chemical compounds that smell bad are coming from the skin and fabric. With our odor-trapping technology,  we’re able to stop those compounds from working their way through the fabric and evaporating into the air.  The antimicrobials stop the growth of the bacteria on the fabric itself.”

Finally, Mr. Trogolo said the company offers over a dozen grades of material with different features that are customized according to the application. “With antimicrobials you need to keep in mind that just having one chemical thrown onto a fabric and thinking it will work in all cases is not realized. Customizing and understanding in detail the use and application condition of the product being treated is crucial to designing the antimicrobial feature into that product,” he said.

Medical Wonders

Polyvel, a compounder specializing in manufacturing masterbatches, supplies antimicrobial masterbatches.

Robert Axelrod, owner of consultancy Plastics by Design and consultant to Polyvel said, “Polyvel
supplies silver antimicrobials with particle sizes that are sufficiently small to be processable in a spunbond or possibly in a meltblown process, that is, micron or submicron particles. We also supply triclosan masterbatches, an organic antimicrobial. All of these are potential antimicrobials for nonwoven medical, wound care and wipes applications,” said Dr. Axelrod.
Polyvel works with a number of silver antimicrobial suppliers who offer silver in carriers such as zeolites or glass.

In a joint venture with Goulston Technologies, Polyvel supplies repellent masterbatch additives primarily for nonwoven producers for medical applications such as disposable gowns and drapes.
According to Dr. Axelrod, “There is a requirement to make the polypropylene fabric impermeable to pathogens which could be borne by alcohol. Polyvel produces repellent melt additives sold by Goulston to nonwoven producers to make the webs alcohol repellent.  You can hold out water but not alcohol. The higher percentage of isopropyl alcohol in water, the better the fabric repellency. Our melt additives hold out a high concentration of isopropyl alcohol.”

Antimicrobials for Meltblown

Americhem supplies silver-based antimicrobial masterbatches to fiber producers as well as spunbond manufacturers for a wide variety of applications including athletic apparel, medical apparel, socks, filters and other nonwoven products.

Americhem is working on an antimicrobial product for meltblown nonwovens and expects to launch the product shortly.  Vaman Kulkarni, research and development Fellow, explained that synthetic fibers and nonwoven products are typically rendered antimicrobial through melt blending.  “The antimicrobial additive becomes an integral part of the fiber/nonwoven article and offers permanent antimicrobial properties. When dealing with high temperature fiber forming resins such as polyester and nylons, organic antimicrobial chemistries lack the thermal stability needed for effective melt compounding.  Silver-based antimicrobials possess high thermal stability and are ideal for such applications,” said Dr. Kulkarni.  Typically the antimicrobial masterbatches are customized depending on the application, such as spunbond or meltblown applications.  

Antimicrobials For Wipes

A leading supplier of preservative antimicrobials for wipes, Lonza offers Glydant, Glydant Plus and Glycacil for bacteriostatic and fungal control for disposable wet wipes. In formulas that require EPA registered preservatives, Lonza provides Dantogard, Dantogard Plus and Glycacil SG. The disinfectant formulation is applied to the nonwoven material during the packaging step. Preservatives are typically added to the lotion prior to being applied to the nonwoven.

Lonza has been focused on getting EPA approval for more naturally based nonwoven materials, according to Mr. Koehl. “Lonza has introduced a line of Geogard preservatives which have been granted Ecocert certification. This means that these preservatives can be used in certified organic personal care wipes, or whenever traditional preservatives may not be acceptable. While makers of EPA-registered formulations may wish to incorporate greener and more environmentally friendly attributes and claims into their products, current EPA regulations prohibit the marketing of such features in any way. EPA has recently announced a pilot program in combination with Design for the Environment (DfE), that is slated for a mid-2010 launch, which may allow approved registrations to utilize the Design for the Environment logo,”said Mr. Koehl.      
Lonza is one company which takes consumer education seriously. “We ensure all products are labeled with instructions to ensure consumers understand the proper use, handling and disposal of all products,” said Mr. Koehl.

Peering in the Crystal Ball

Finally, as nonwovens expand their usage in wipes and other applications, they will continue to depend on the use of antimicrobial protection to stop the spread of germs and disease.
“Nonwoven wipes competing against paper towels or textiles are now used as delivery mechanisms for polishes or antistats and they use micro denier fibers to be more versatile,” said Aegis’ Mr. White. “This has given them not only better utility but better sustainability and that sustainability demands antimicrobial protection. If you use things more than a one time use, you now are challenged with fungal or bacterial deterioration of those materials which may lessen their useful life.  The problem is huge where microbes impact the serviceability and sustainability of nonwovens. Bacteria, fungus, odors, staining, deterioration or health concerns are all on the list.”

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