A hologram can also be a guarantee of the authenticity of a product, as it is very difficult to copy.
Holographic effects can now be applied to plastic and fiber-based packaging and plastic products in an affordable and ecological way. The technology introduced by Finnish company Iscent Oy is based on changing the topography of the plastic or paper surface.
At the end of 2012, Iscent Oy commercialized the hologram technology developed by VTT.
Traditional hologram technologies are based on metallized solutions, laminated structures or effects produced with UV varnishes. The effect achieved with the new method does not require UV varnish or other additional additives, as the rainbow color phenomena are created by changing the surface of the plastic or paper.
“We print the pattern directly onto the surface of the material. This way, printing is ecological and cost-effective, as no additives are used in the process,” notes Valtteri Kalima, who is responsible for Iscent's production.
Wider than before
The hologram printing method used by Iscent is not a new one, but commercial hologram webs already in use in the printing industry are almost always designed for narrow products.
The process developed at VTT makes it possible to produce a hologram-printed end product up to 1 millimeters wide. This enables a new type of business and large print runs.
“Our competitors use narrower production lines. Typically, a film with a width of 300 millimeters is not enough for the needs of the packaging industry, for example.”
What's innovative about widening the track to 1 millimeters?
"Nothing as such, of course. The core of the technology is in the installation of the printing cylinders. Such a wide web is challenging, as the reliefs are in the nanometer range," says Kalima.
The purity of the process is important to Kai Sundström, Iscent's printing guarantee man.
Heat-printed
Iscent has a spacious production facility in Martinlaakso, Vantaa. An Italian Uteco printing press has been installed in the facility built in Sanomala.
The method used by Iscent is based on hot pressing technology, where a pair of calender-type rollers creates nip pressure. A plastic or paper web is guided through it. In other words, the device has a film and a printing plate, with pressure rollers between them.
“The holographic effect is copied into the material passing through the rollers by the effect of temperature and pressure,” says Eero Hurme, who is responsible for Iscent's sales and marketing.
In hot-press technology, temperatures vary from around 60 degrees Celsius up to a maximum of 150 degrees Celsius – depending on the material being printed.
There is actually only one mandatory property in the printed material for hologram printing to be successful.
“The material must be thermoformable. For example, uncoated copy paper will not work,” Hurme points out.
Text: Jaakko Liikanen
Photo: Matti Immonen
The full article can be read in the 4/2012 print edition of Paperi ja Puu magazine.
