Ultrasound technology for chemical-mechanical finish
In light of the coronavirus pandemic and the increasing number of hospital infections around the world involving multidrug-resistant pathogens, antimicrobial textiles are coming back into focus.
An innovative, ultrasound-based finishing
technology developed by Sonovia, Brückner
Textile Technologies, and Weber Ultrasonics
now offers some crucial advantages: because
the impregnation meets industrial requirements for wash
resistance, it remains effective for a long period of time
– even against coronaviruses. Furthermore, the new
“sono-finishing” process minimizes the environmental
impact associated with conventional textile finishing.
Antimicrobial textiles are nothing new. But because
the majority of impregnations that protect against
bacteria, viruses, and fungi use chemical binding agents
that only deliver limited wash resistance, the protective
effect only lasts a certain amount of time. Additionally,
the chemicals and substances used can be harmful to the
environment. This may not only impact the environment;
it can also result in pollutant residues on finished
products. “To ensure antimicrobial textiles like those used
in clothing for medical workers, hospital linen/laundry,
and oronasal masks significantly reduce the risk of
Ultrasound technology for
chemical-mechanical finish
In light of the coronavirus pandemic and the increasing number of hospital infections around the
world involving multidrug-resistant pathogens, antimicrobial textiles are coming back into focus.
infection, the impregnation must be able to withstand
frequent laundering at the high temperatures required in
the medical sector. They cannot lose efficacy over the
course of their normal useful life,” says Liat Goldhammer,
chief technical officer at Sonovia Ltd, setting out a key
requirement. Furthermore, textile finishing must meet
today’s high economic and ecological standards.
Sonochemical process offers solution for all types of
textiles in 2017; the Israeli startup began industrialising
a patented sono-finishing process developed at Bar-Ilan
University in Israel. The one-step, sonochemical finishing
process is suitable for all types of textiles – whether
they’re made from natural fibres like cotton, linen, and
silk, synthetic materials, or a blend of both. The
procedure uses zinc-oxide nanoparticles as an active
medium and is based on the physical phenomenon of
acoustic cavitation: when exposed to ultrasound, small
bubbles continuously form in the solution mixed with the
nanoparticles, which then expand and collapse within
split seconds. This creates high-energy microstreamingpatterns, which move at around 500 meters per second.
These carry the particles with them and embed them
firmly in the textiles. “This is a distinctive feature of our
technology versus conventional textile finishing
processes that use chemical binding agents,” explains
Liat Goldhammer. “With sono-finishing technology, the
particles are mechanically embedded, so the
antimicrobial properties remain in place for a long time.”
What’s more, no polluting binding agents are required in
the process, and the use of chemicals can be reduced by
up to 50 percent.
The formation of cavitation bubbles via ultrasound is
crucial to ensure the reliable application of the
antimicrobial zinc-oxide particles. Standard ultrasonic
systems cannot be used for this.
Strong partners for industrialisation
To transfer the technology from the university
laboratory to large-scale industrial production, Sonovia
partnered with Brückner Textile Technologies, a
manufacturer of textile finishing systems and process
technology developer, as well as Weber Ultrasonics, an
international manufacturer of ultrasound technology
components – both world leaders in their respective
industries. “Both companies were impressed by the
technology’s potential and entered into partnerships
with us. This cannot be taken for granted with such
established firms – after all, collaboration with a startup
always comes with certain risks,” comments Liat
Goldhammer.
While the R&D department at Weber Ultrasonics came
up with a made-to measure ultrasonic concept, Brückner
developed and built a corresponding application unit that
can also be integrated into a wider, continuous finishing
process. The first system prototype for the sonochemical
process has been in use at Brückner’s technology center
since early 2019.
Technological, environmental, and cost advantages
In addition to ensuring maximum process reliability,
key aspects included meeting the modern textileindustry’s high standards in terms of productivity,
reliability, sustainability, ease of maintenance, and cost
effectiveness.
Compared to conventional textile equipment, the new
procedure not only offers the benefits of more longlasting
antimicrobial properties and being more
environmentally friendly; it also allows for cost savings.
“Although development is not yet complete, initial,
conservative calculations suggest potential savings of
around 10 percent from the reduction of chemicals used,”
comments Liat Goldhammer.
The new application unit, which is similar to a
padding mangle, can easily be integrated into existing
plants and lines. It can be used for finishing both woven
and knitted fabrics, as well as nonwovens and carpeting.
Proven wash resistance and efficacy – even against
coronaviruses To prove the lasting and reliable
antimicrobial efficacy of sonochemical textile finishing,
Sonovia conducted testing together with renowned
international textile research and certification institutes.
The tests confirmed that the finished fabrics still retained
their full antimicrobial properties after multiple wash
cycles at high temperatures.
Sonovia now manufactures and sells antimicrobial
oronasal masks made out of textiles that use this
technology. Tests carried out in summer 2020 revealed
more than 99 percent efficacy against SARS-CoV-2.
Additionally, the mask filters 95 percent of 3 microns
particles, the particle size which has been identified by
the WHO as relevant to the spread of COVID-19.
The new technology’s proven, lasting protective
effects, in addition to the user-friendly and sustainable
process, make it an optimal solution for finishing
clothing for medical and care workers and laundry/linen
in hospitals, senior homes, and hotels, as well as many
other areas where hygiene and infection control are
critical. The fashion and sportswear industries, as well as
the automotive sector and railroad car fitters are also
interested in sonochemically finished textiles. Relevant
tests are set to be carried out at Brückner Textile
Technologies’ technology center starting in the second
quarter of 2021.
