The ink system uses a revolutionary photo-initiator developed specifically to satisfy food migration issues. Mirage MD, Steve Fisher, is understandably proud of his technical team’s achievement. ’We have worked on cationic UV technology for 20 years and now have an ink system free from any significant migration,’ he reports. ‘Some companies claim “low migration” with conventional UV curing systems, with little likelihood of consistently remaining within permitted levels of migration while running at typical printing speeds. We can now offer our Quartz Artemis system where nothing of any significance migrates. This has to be the future ink system for food packaging and it’s fitting as it represents the culmination of 20 years of cationic development at Mirage. The product has now been printed commercially for several months.’
Acceptable toxicological data exists on most components utilised within the Quartz Artemis ink formulation, which permits migration levels up to 50ppb (parts per billion). For those components where there’s insufficient toxicological data, then levels below 10ppb are required, a much easier task for cationic where the ink continues to dark cure.
In order to ensure migration levels are being met, Mirage commercially printed a shrinkable PET and requested Pira to undertake a complete and demanding migration evaluation. Tests showed no detectable migration, confirming a significant advancement in safe food packaging. It also provides the printer with a safer and affordable alternative to non-cationic UV systems where, in the absence of toxicological data,.migration levels below 10ppb have to be consistently achieved to satisfy EU legislation.
The 2008 revision of the Swiss ordinance on materials and articles in contact with food have brought into force new regulations on food packaging inks. This ordinance will become legally enforceable from April 2010 with the introduction of positive lists for components used in printing inks. This will make the Swiss the first country to take into law the selection of safe components used for food packaging. The Swiss Federal Office of Public Health is working in conjunction with EUPIA in compiling the lists to ensure the April 2010 deadline is met. It’s conceivable that a World Standard may be subsequently agreed as a consequence of the Swiss initiative.
‘The last three years of developing Quartz Artemis have been intense but we have finally achieved the objective in developing a competitively-priced cationic UV ink system free from any obvious odour, that adheres remarkably well to all polymer substrates, cures “like a rocket” and is within allowable migration limits.’ says Steve Millen technical head at Mirage.
Mirage customers are queuing up to evaluate the product and Mirage has commenced discussions with several end users directly with the expectation that Quartz Artemis becomes the accepted choice for safe food packaging where UV curing inks are concerned.
Caption: Mirage Ink is represented in South Africa by Millian Inks. Seen in the lab are Millian proprietors, Ian Trethowan and Clinton Miller (just out of interest the name Millian is derived from Miller and Ian!)
Tracey Young, chemist and UV co-ordinator at Mirage, adds: ‘The substrate tested for migration by Pira was polyester, as a typical shrink sleeve application for HDPE milk bottles, using full fat milk under a worst-case storage scenario. The material used for the migration tests was printed at commercial running speeds and not produced in a laboratory, so that true production conditions were reflected in the migration results.’
And a final word from Steve Fisher: ‘I’m confident any UV printer applying a rudimentary level of process control is capable of achieving acceptable migration results and excellent adhesion to polymer film with the Quartz Artemis system, without risk or fear of product recall. Mirage is committed to the promotion of safe food packaging and is the first company in the world to have this product commercially available for use within the flexo printing/food packaging market without the presence of potentially harmful bi-products such as 4 methyl benzophenone, itx and benzene, all of which are capable of migrating into the food. This has been a great team effort and I’m immensely proud of this achievement.’
And putting this into context for local printers, Ian Trethowan of Millian Inks (local representative for Mirage), comments: ‘The important thing for South African UV printers to remember is that responsibility for supplying printed materials safe for food packaging rests with the printer. This is where an understanding of the primary difference between cationic and free radical technologies becomes critical!’
Ian goes on to explain that printers must be able to guarantee that there’s always enough curing intensity to terminate all the reactive species in a low migration free radical UV ink system, in order to guarantee less than 10ppb of ink that could migrate into the food – either through the substrate/package or via back transfer or set-off in a printed reel where the unprinted surface is in contact with the food.
‘Artemis cationic inks – given sufficient initial UV intensity – will “dark” cure (continue to cure after exposure to UV light) so that no unreacted species remain in the packaging that could migrate into food,’ Ian explains. ‘In addition, the Artemis cationic ink system has toxological data for all the main components in the ink which means that the acceptable migration limit for these components increases to >50ppb, further reducing the risk to the printer.’
Editor’s Note: At the time of going to print Mirage awaits further migration results from other commercially printed food packaging structures. In addition to cationic UV inks, Mirage also supplies free radical UV inks, water-based and solvent-based inks. For further information on the difference between cationic vs free radical, refer to PPM April 09, p62.
Millian Inks/Ian Trethowan
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