Antimicrobial silver coating rolled out for print

An antimicrobial coating previously only used on textiles has been rolled out to printed products, including hospital literature and inflight magazines.

N9 Pure Silver, developed by UK and India-based N9 World Technologies, has been used in sportswear, underwear, socks, workwear and soft furnishings for around four years and, after two years of testing, is being targetted at new markets.

The coating, which the company claims reduces surface bacteria by 99.99%, has been introduced to consultant directories at private hospital Spire Healthcare and to a range of Ink Publishing titles, including the customer magazines of Easyjet, Eurostar and Thomas Cook.

"Silver is a natural antimicrobial agent and this is exactly the same coating as for textiles – particles of pure colloidal silver suspended in de-ionised water," said N9 print development manager Derek Adams.

The coating can be applied with an inline coating unit or, for heatset web presses, can be mixed with silicone to be applied at the post-oven stage of production, Adams explained. He added that the company also believed N9 Pure Silver was suitable for gravure printing as well.

"We have had a conversation with someone about gravure. I was told it would be possible to apply as a vapour with a spray bar. So in theory it could work on gravure as well," said Adams.

According to N9, Pure Silver kills 99.99% of bacteria including E. coli, MRSA and C. diff. "It is also non-migrating – it doesn’t come off the page. Once it’s there, it’s there for good," said Adams. He added that, thanks to its special 'blue' formula, N9 Pure Silver doesn’t discolour print in the way that some other silver-based antimicrobial coatings can.

Potential future applications for the coating are wide ranging, said Adams: "This is very, very inexpensive, we’re looking at, depending on the job, adding probably less than 1% across the job. Because of this low cost it has got the potential to become the industry standard. It could be used on any piece of shared print."

Adams said the company was in talks with a number of magazine publishers and playing card manufacturers, and also with one potential distributor.

Bank notes were another key future application, he said: "The other great thing about this is it prevents the growth of mold, so with bank notes, though they may be stored for unknown lengths of time, that could be quite a good safeguard."

N9 Pure Silver joins another recent launch in the antimicrobial coating market, BioSeal. This coating promises to reduce surface bacteria by 99.999% and consists of a biocide that involves micro-particles in a resin.