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Flint Group - The UVolution of ink -New UV Curing Capabilities and Technologies

As the price of oil continues to rise and the necessity for lower environmental impact increases, technology must adapt in order to conform. Energy curable inks and coatings are already known to have one of the lowest environmental impacts, when compared to solvent or waterborne systems, with zero VOCs and minimal energy required to cure. Within the past few years, developments have been made to make UV curing of inks and coatings even more energy efficient, thus reducing the impact on the environment even further.

The commercial use of UV curing inks and coatings has been around for many years and continues to gain popularity based on its many advantages. The biggest of these advantages is the fact that they contain little to no VOCs. By the elimination of the VOCs, UV curing does not need to either recapture or incinerate the exhaust as with traditional solvent / heatset inks and coatings. This can also reduce the need for government permits, based on environmental impact. The amount of energy needed to cure a UV ink or coating is much less than that needed to dry solvent or heatset inks and coatings. The instant cure of the UV inks and coatings results in faster turnarounds and secondary finishing directly off press. Although the impact of UV curing on the environment is minimal, there is always room for improvement

One technology that has emerged recently is the use of so-called “HR” (highly reactive) or “LE” (low energy) lamps. There are now many configurations appearing that are based on modifications to the lamp, reflectors and power control units, which help eliminate some issues with traditional UV curing.

One of the early curing systems of this type came from Komori, who introduced their H-UV curing system in 2011. This system consists of UV lamps that are doped with iron. The use of iron as a dopant shifts the primary output of the lamp to higher wavelengths. Along with this modification, the lamp and reflectors filter out wavelengths lower than 290 nm which eliminates ozone creation and therefore the need for exhaust is removed. This modification also reduces the greater than 450 nm output, thus reducing the amount of wasted energy associated with visible and heat energy.

With the use of highly reactive UV inks (HR), it is suggested that a single H-UV lamp can cure up to 400% ink coverage plus coating at maximum press speeds. By reducing the number of lamps as Komori suggests, significantly lower energy consumption and lower equipment cost, when compared to traditional UV lamp systems will result. If a dry trap application is required, an additional lamp can be used interstation. [1]

In 2012, Heidelberg introduced the DryStar LE UV lamp system. The LE UV lamp system was developed for use on commercial, light packaging and speciality applications. The DryStar LE lamps are an entry level system using special UV reflectors that reduce the heat associated with normal UV lamps. The LE system can be equipped with special lamp materials that eliminate the wavelengths below 290 nm therefore preventing the production of ozone. Without the production of ozone and excessive heat, the lamps do not need an exhaust. If regular lamps are used, Heidelberg offers an activated carbon filter which also reduces the need for an exhaust. The lamps can also be doped with iron which produces wavelength outputs toward the higher end of the UV spectrum. The DryStar system has power controls which allow the lamps power to be reduced, allowing for greater energy savings. Heidelberg stresses that this system can be used with both traditional UV inks and the high reactivity inks that are now being developed for other low energy UV systems. The DryStar LE UV system can be equipped with one, two or a maximum of three lamps for each machine.

Also in 2012, KBA introduced the VariDry HR UV system. The VariDry HR UV system can be adjusted to give output energies between 80 and 200 Watts/cm. KBA is stating that up to five colors of ink can be cured with just one UV unit. By reducing the number of lamps and the ability to reduce the output energies, results in reduced energy costs. KBA is offering the system with an optional ozone-free lamp with an activated carbon filter. This allows the lamps to be used without the necessity for ventilation exhaust. The VariDry HR UV system uses conventional mercury lamps which allows for greater lifespan than iron doped lamps. [2] [3]

Air Motion Systems (AMS) introduced the Titanium HW-UV lamps at Drupa 2012. The Titanium HW-UV lamps are high wavelength (HW) mercury lamps that are doped with iron to give energy outputs toward the higher wavelength area of the UV spectrum. Because inks are optimised to cure at the higher wavelengths and are high reactive, the need for multiple UV lamps is reduced. In most cases, the lamps are positioned before the perfector or after the coater. The Titanium HW-UV lamps can be equipped with special bulbs that eliminate the energy given off below 290 nm thus removing the amount of ozone created. Without ozone, there is no need for exhausting of the lamps resulting in a smaller footprint on press. This allows the Titanium HW-UV and the XP5 Peak LED-UV lamps to be exchangeable. The output of the lamps can be controlled to allow for greater cost savings. [4]

But who is this low energy curing, highly reactive technology aimed at? Flint Group’s Richard Wilson, UV Product Management Director believes it will be attractive to the fast turnaround conventional printers who can save energy costs by eliminating infra-red drying and warm air drying for water based coatings, turning around work in a matter of minutes, saving on work-in-progress and improving delivery times

“As commercial printers are pushed to offer shorter and shorter lead times, work-in-progress must be kept to a minimum and jobs need to be turned-around for next day delivery. Low energy UV curing will allow the conventional commercial printer to manufacture to these new targets. We can see the web-to print sector in particular being early adopters of this technology because of the dramatic reduction in manufacturing time and the lower entry cost than traditional UV” stated Wilson.

Existing UV printers will also find the low energy option appealing because of the energy and heat savings potential, and the green credential enhancing ozone elimination.

Flint Group in collaboration with leading OEMs and lamp manufacturers has developed and is now commercialising a full range of low energy UV curing highly reactive inks and coatings under the name Ultraking® XCURA. One of the unique key features of XCURA is that it has been formulated for use on the widest range of substrates, including some non porous types. – a real winner where printers need quality and flexibility on tight schedules. XCURA have a very high colour strength, display excellent ink/water stability and require lower levels of energy to operate. They comply with ISO 2846-1 and are suitable for printing to ISO 12647-1 standard

“Working with XCURA inks and coatings allows printers to lower their costs by reducing the number of UV lamps needed to cure the inks, eliminating the extraction that’s needed for traditional UV curing and reducing energy consumption, due to the efficiency of these types of lamps.” Explains Rod Balmer, Director of Global Research and Product Development.

XCURA has been developed in Flint Group’s global research centre in Ypsilanti, Michigan. “These inks are formulated using a selection of photoinitiators which absorb at the higher end of the spectrum and are optimised for high speed curing. Typically these materials are more costly than their traditional counterparts, but were specifically selected to follow EuPIA guidelines.” Concluded Balmer.

After testing at our OEM partner facilities in Europe, XCURA has been beta trialled across Europe under the watchful eye of Richard Wilson. “The field trials culminated in Heidelberg Moscow running live press demonstrations with Ultraking® XCURA ink and Ultraking® XCURA LAC high gloss varnish, printed in-line, with no inter-deck curing between the last print unit and the varnish unit. This perfectly demonstrated the synergy of the two products with little or no dry-back. To push the product to its limit, the demonstrations took place at the time of Polygraphinter Exhibition in November 2013, in front of a group of very interested observers looking-on as the products got their first public showing.

Jim Buchanan, Business Development Director UV Sheetfed has this to say “As an industry we have witnessed exceptional growth in the use of UV Ink of up to 12% year-on-year, and during 2013 this development has clearly been underpinned by Low Energy themed technology, which kicked in with great effect in Q2 this year. We expect this trend to continue for the foreseeable future as shrewd commercial printers switch-on to the benefits of UV technology. This migration from conventional to UV is a whole new area of volume growth for the UV ink market.

At Flint Group we are ideally positioned to offer what we believe is the most comprehensive package of products and services for this technology through our renowned Perfect Synergy programme. We identify our focused approach to collaborative development with the industry's leading OEM’s and UV lamp manufacturers, as a significant contributing factor to the early success of the XCURA products. We have worked hard to optimise XCURA’s performance across a wide range of applications, to ensure it offers the ultimate in versatility to the user.

We are poised to follow up this launch with our XCURA LED products for Sheetfed applications early in the New Year, and this will bring an exciting new dynamic that we think will be appealing to the industry on a wider scale given the potential energy savings and process efficiency gains derived from the use of LED as an alternative curing method.

This will complete our UV ink portfolio and underline our position as one of the industry key innovators and pioneers of UV technology.”

Ultraking® XCURA is launched globally on December 4th with immediate availability.