02 June 2019 Analogue Printing Technologies

Ink producers adapt to photoinitiator challenge

After certain photoinitiators were withdrawn last year, ink makers have been working to achieve the same performance with a more limited choice of components. Now they are confident that have solved the problems.

Ink suppliers are rolling out new standard and LED UV inks following the decision to remove 13 photo initiators from the Eupia approved list.

This follows on from the shortage of the photo initiators last year and the introduction of Reach regulations which made it overly expensive for suppliers to gain approval for compounds with limited demand, leading to these to be with drawn from the market.

The net result has been a hasty reformulation of some inks that have been available on the market at a point that LED UV in particular is becoming more important in the commercial print sector.

The change in regulations caused disruption to printers as suppliers have tweaked formulations to ensure that ultimately there would be no loss of quality. Sun Chemical has launched SunWave Lumina with these thoughts in mind. “There has been long development in a system that performs exceptionally well in offset presses to compared to other system.

“It has a fast curing and exceptionally good ink water balance.”

The ink has been put through its paces during extensive field testing. Currently it is a four colour only ink set with matched fount solutions. The range will increase and will include a low migration LED UV ink, currently being evaluated, and version for flexo printing.

Huber has also adapted formulation to ensure that all inks are fully Eupia compliant. The company had to change four of the photoinitiator compounds it had been using as these are no longer permissible. In all double that are no longer available to ink makers.

Like Sun, Huber reckons its new ink delivers improved performance. “Feedback from customers has been exceptionally positive,” says Roland Schröder, product manager UV-Offset. “There is a full spot colour mixing system with white and metallics.”

Even with the LED UV inks the company says it “is at the same technical level as the previous formulation, but we know that improvement is necessary and a development project has been started.

Toyo is also producing a new series of inks that both take into account changes in regulations for photo initiators and will be more stable in terms of ink/water balance. That new ink is due within weeks “It will be as stable as the ink we have a year ago,” says a spokesman for Toyo. In the first phase this will be four colour only.

Siegwerk which has almost no penetration of UV paste inks in the UK says it had anticipated that certain photo initiators would be withdrawn from the market and had reformulated its inks so that there are fully available.

This was done as part of work to make the inks fully recyclable. UV inks are frequently considered impossible to recycle, but working with Ingede, Siegwerk has developed an LED UV inks with better recycling properties than standard litho ink. The ink was two years in development, aiming to get pigment particles to be small enough to be washed off the paper, resulting in a 93/100 score.

“Immediately after the reclassification of photinitiators, everybody wanted the old ink formulations back. We are now almost at the same point we were last year and customers are now satisfied,” says Siegwerk.

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Change the recipe

Change the recipe

Siegwerk has changed its formation ahead of requirements to do so. And others are likewise making changes hoping to achieve the same performance if not better that printers have previously enjoyed when different components could be used.

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