Hanrahan says that another limitation of this application is
that the retailer loses flexibility, because the antimicrobial is added far
back into the supply chain. "It means you have to carry inventory. And the
product may be marked up along the supply chain," he says. "This
application tends to be more durable, but not as economical." According to
Trogolo, this kind of application is best for end-uses that need large amounts
of one kind of fiber, such as upholstery or uniforms.
Other Applications
Other ways of applying antimicrobials to textiles are less
common. Noble Biomaterials' X-Static product is a "universal and permanent
coating of silver on substrates from yarn to fabric," says the company's
Chief Commercial Officer, Joel M. Furey. This system is "primarily
intended where users need high levels of performance," says Furey. This
means "high kill rates of bacteria and fungi with a fast kill action,"
he says.
Another product with a high kill rate is chlorine. According
to Wiencek, n-halamine binders "have a unique way of dealing with
antimicrobial treatments-they bind chlorine to the fabric, so that they can
make claims that EPA-registered chlorine bleach can make." According to
Fruchart, chlorine is "as good as any disinfectant. A 99.9% killing rate
is reached within an hour, which is quicker than most other aqueous treatments."
This is Fruchart's post-consumer after-treatment method.
The chlorine is used as an antimicrobial and is recharged
onto the fabric by adding chlorine bleach to the laundry. A drawback to this
system, says Wiencek, is that although this technology is intended for niches
that require industrial laundering, not all industrial laundries use chlorine-based
bleach.
Fruchart remarks that in a laminated product, "instead
of treating the fabric, an antimicrobial agent is added in the adhesive. The
active ingredient will radiate, thus creating an inhibition zone, while
remaining resistant to laundering." Adhesive treatment makes it possible
for laminated polyester fabric to maintain an antimicrobial activity despite
prolonged washing cycles.
In a similar vein, Fruchart notes that "one technique,
although not frequently used, consists of placing antimicrobial agents
contingent in between two membranes. The membranes' permeability allows the
controlled release of active ingredients, which migrate to the surface. This
type of process is mainly....for products that do not get laundered, like
mattress covers and separation curtains. With complementary methods, protection
can last for several years."
A flexible technology like the Aegis SiQuat can be applied
in or onto fibers, fabrics, or post-consumer laundry treatment, says Bob
Montincello of Aegis Environments. "This versatility in application
provides textile mills with options... [that] keep down costs and maximize
performance," he says.
"The best application procedure for antimicrobial
treatment will provide for mill qualification testing and good, solid SOPs,
along with quality assurance procedures that are based upon useful chemical
analytical and microbiological tests," says Curt White of Aegis
Environments.
Does the Application Matter?
Depending on the product's end-use, the marketing claims
made, the antimicrobial's chemical and physical properties, and its mode of
antimicrobial activity, the antimicrobial's application does matter.
Some antimicrobials can be applied in several ways, but
other technologies are limited to one mode of application. A product designer's
main priorities, whether for flexibility, durability, cost, compatibility with
other finishes, spectrum of microbes to be fought, or high-performance, may
influence the application, and the antimicrobial, chosen to protect that
product. Application matters!
Originally published in AATCC News;
June 2009 © AATCC
About the Author
The author
is associated with AATCC.
