‘With the integration of Varcotec’s product technology, we’re adding a specialised solution for various applications to our portfolio, reinforcing the holistic nature of our offers for the packaging market,’ says Hanns Martin Kaiser, Siegwerk’s VP Paper & Board EMEA. Even if printed surfaces don’t generally constitute a hazard, consumers continue to be exposed to potentially contaminated surfaces. As different germs (eg viruses, bacteria, fungi) exhibit varying survival times, the Lock 3 technology makes a valuable contribution to avoid risks of transmitting bacterial and viral infections when products’ printed surfaces (outer packaging, partitions, exercise books, etc) are handled by multiple people in a short time. Lock 3 antimicrobial solutions help to provide extra security in a multitude of applications by interrupting chains of infection early on.
Reducing germ load on printed products
Scientific data shows that germs can survive on surfaces from a few hours to several months. ‘Until now, it hasn’t been possible to apply a reliable coating to absorbent substances, such as paper and board, to continuously and permanently destroy those germs,’ explains Varcotec’s, Joachim Frings. ‘With Lock 3 we’ve developed a varnish system that demonstrably reduces the germ load on a wide range of printed products.’
The water-based overprint varnish Lock 3 allows for permanent, independent disinfection of printed surfaces under ambient room lighting or in open daylight. It contains a patented substance, taking advantage of the principle of photodynamics: the photocatalyst is activated by visible light and transfers the energy thus absorbing the surrounding oxygen. This process creates so-called singlet oxygen, efficiently killing germs through oxidisation. [Singlet oxygen is routinely used for the treatment of tumours and degenerative diseases. Ed.]
The effectiveness of this varnish has been validated by several independent testing institutions. Tests have shown that Lock 3 varnishes can kill both bacteria (according to ISO 22196 for paper and board) and infectious viral particulates (based on ISO 21702) by more than 99%. Additional tests against other virus strains, including three members of the coronavirus family, are currently underway.
Lock 3 can be applied to paper and board by means of all commonly used printing and coating equipment. The first pilot applications on plastic films are underway.
According to Siegwerk, this varnish is currently the only fully-effective antimicrobial technology on the market that functions independent of moisture and temperature conditions and remains effective on dry surfaces. The photodynamic effect is temporarily suspended in darkness, but reactivated immediately upon renewed exposure to light. This varnish remains effective for up to three years.
Other comparable technologies, such as coatings containing silver and copper, require the presence of moisture or even UV radiation to obtain sufficient effectiveness for disinfection. Lock 3 dispersion varnishes are free from heavy metals, odourless and without impact on recycling processes.
These products will first be available in Germany, then gradually launched in Europe with all countries in EMEA serviced by end of this year.