Water, Water, Everywhere but not a Drop to Drink

Phil Jackman is Global Product Manager for Digital at Sun Chemical and I caught up with him after the InPrint Show to give his roundup of 2019 and a projection for 2020.

Hello Phil, was 2019 a good year?It has certainly been a busy year and we are mostly where we want to be with our inkjet business, despite some aggressive growth targets that we had set for ourselves. I guess this should be set against less favourable results for some other companies that suggests that inkjet is becoming increasingly competitive. Both the hardware and the ink sales have struggled in some areas of inkjet and overall industry sales in the print sector are not as positive as expected.

How was InPrint for you?
As always, InPrint was very good for Sun. The show itself certainly seems more mature and evolved perhaps because inkjet technology now is more readily available, and less conceptual. The show is assembled in the right manner and meets most customer project needs.

One of the largest changes since the early InPrint shows I would say is the knowledge of the visitors and the reality of their expectations. A few years ago, people came with impossible challenges for printing, and frankly unrealistic ideas. Since then, the technology has evolved and peoples’ knowledge has improved, so we are more likely to meet their expectations. So, we now see the coalescence of realistic expectations coupled with technical capability and this is leading to progress.

So InPrint remains a good platform and barometer of the industrial printing sector?
Yes. The show has stabilised along with the market and maybe the hype isn’t as it once was, but the biggest change is maturity. It felt like there were slightly less visitors, but we had higher quality conversations. I think it’s positive. I’d much rather have real conversations with real opportunities as opposed to interesting but generally pointless ones!

So industrial Inkjet has moved onto another level then?
Since the inaugural InPrint in 2014 it has yes. From a hardware/software perspective most inkjet applications should now be possible. Current print heads and associated electronics can achieve the necessary result for most applications at an acceptable speed and quality. So, the ink is the enabler - the performance of the ink in the print system, on the substate and its suitability for the end use (physical & chemical performance and legislation) remains the most important aspect for project success. I believe that your recent survey reflected this opinion.

Future of Inkjet 2020 Survey & Report, FM Future

What about packaging? Is this going to develop as the next inkjet market?
Moving into the packaging arena, and certainly food packaging, the legislation is of paramount importance – where the ink is available and wasn’t a constraint, the market has already started to move. Take inkjet labels or direct to container as examples where UV inkjet (sometimes with Low Migration capable chemistry) has been available for several years now and is really starting to grow. Sun Chemical launched its award-winning low migration capable UV inkjet technology around 6 years ago, so UV inkjet in packaging is quite well established, but is still a small percentage of total volumes. However, the main thrust of our R&D in recent years has been with aqueous ink technology for packaging applications. The main target markets for this are corrugated / carton and flexible packaging. We have evolved water-based inkjet chemistry now where it is able to be demonstrated even for the most demanding of applications. In turn, this provides the opportunity to look at other applications beyond mainstream packaging, perhaps into more industrial applications where it was previously a challenge and deemed not possible.

For example, Direct to container applications may need water-based inkjet inks in future although now it is predominantly UV. Water-based solutions are being requested by end-users and this change will create the pull that is required to accelerate investment in development and a greater adoption will occur.

Why is water-based inkjet ink so difficult to make?
Water-based inkjet is not necessarily more difficult to manufacture per se, but rather it is the formulation approach and R&D required to balance all the technical targets that make it difficult.

Compared to water, UV remains a highly effective curing process to use in inkjet (where it can be used) since you can separate the printing and curing phases of the process. UV ink will remain fluid in the print head and not block nozzles as it will not cure until it is exposed to UV light. In contrast, inks that dry through evaporation pose a potential risk in the nozzle area because if they dry there you could easily block nozzles. So, the main issue is developing an aqueous inkjet ink that dries quickly onto a substrate once printed and forms a dried ink layer with acceptable resistance properties yet remains ‘open’ at the nozzle and available to print. i.e. not dried in.

The second challenge is the issue of image quality on substrates with low porosity. Water-based inkjet onto absorbent paper is relatively easy as the inkjet drops have little time to coalesce before they soak in. In contrast, on highly coated stocks or non-porous substrates such as flexible packaging films, wet-on-wet inkjet drops will tend to coalesce before they are dry, and colours will bleed into each other if not actively controlled. This is where the combination of ink and primer is crucial. A primers main function here is to supply drop control so the inkjet drops land on the primed surface and will not bleed into each other and blur the image. When we started off several years ago our expectation was the inks would be relatively simple formulations and the primers would not only provide the image quality but also promote drying and provide the physical resistance properties too. The reality is that there were performance targets in terms of print speeds and having an ink that dries faster plus had more functionality in terms of film properties that soon became a necessity. The skill was to optimise these requirements without compromising open time and jetting performance in the print heads. The primer is still an essential part to achieving the goal but the ink, therefore, must contribute to performance in industrialised solutions.

This is particularly so when looking at flexible packaging and this was the main driver for our R&D, as Sun is a dominant and well-respected supplier in the conventional packaging world. We have developed extensive knowledge and a toolbox of ink and primer chemistries that we can modify for varying drop control and drying conditions. This toolbox could then be applied to other markets and substrates, so applications like vinyl flooring, direct to container and metal decoration for example now become within reach with aqueous technology and become potential projects with which to progress. Individually they may not have justified the R&D spend but collectively they should all benefit. This core technology is getting to the point where you can realistically consider putting it into previously unobtainable applications.

The power of the technology is unleashed via the synergy of the combination of analogue pre-coatings used in conjunction with aqueous inkjet inks. Certainly it hasn’t reached the end of the road and this technology will continue to evolve - you cannot develop the two components independently, they have to be developed together - there must be a close relationship between the ink and primer to reach the best solution. So, the primer needs to be optimised too. We are fortunate at Sun Chemical as we have Sun Evo (our brand for coatings for digital applications) and that team focuses on developing primers for our inkjet inks. They are part of the Functional Coatings group that develop coatings and functional barriers etc for various packaging applications, so we have a wealth of experience to tap into.

It feels as though there is a transition from UV inkjet into water-based, although many existing UV inkjet markets may not need to change in the short term. The areas of most interest are new markets that will be unlocked by water-based and their rate of adoption, in combination with the potential market sizes, means that aqueous inkjet could soon overtake UV. This is the period of transition that we are in now.

Is the main driver sustainability?
Although aqueous ink components are inherently more sustainable than UV, it isn’t the main one.

Food packaging requirements are probably the main driver. Creating prints with less hazardous materials is important when you manufacture food packaging. Sun Chemical is a leader in this regard for conventional print and offers decades of experience and confidence for brand owners as they already know and trust our capabilities and commitment to ongoing performance monitoring and Good Manufacturing Practices (GMP) during ink manufacturing, globally.

Low film weight is another driver as the build height of UV inkjet is deemed too much for some applications. And in many high-volume markets, it is cost.

So, there is an economic case for adoption of water-based?
Water-based inks do have the potential to be less costly than UV, but economies of scale are not yet fully realised. The raw materials are potentially less expensive compared with UV, but the manufacture of the pigments, dispersions and finally the ink is equally as complex and contributes greatly to the final cost. Ink is often regarded as too expensive in digital printing, but the value proposition is usually strong. In applications where ink consumption per machine is lower, such as wide format printing, the value added by the ink per square meter is large, so choosing a high-performance UV ink is important. However, in high speed packaging printing machines, the lower value per square meter of print, in conjunction with the much higher ink consumption, exposes the inkjet ink as being more price sensitive. At the end of the day, the price will have to come down, but it is not there yet as the development and performance are key to initial success and the volume sales are not yet established.

Is water-based just as bad as UV in terms of the environment?
Some of the components of UV inks are deemed as hazardous to both the environment and to humans, but this is well monitored. So, on UV ink labelling, you will generally see more hazard warning symbols than on a water-based ink – but often no more than you can find on household products under your kitchen sink. UV raw materials are frequently reassessed and often reclassified and potentially phased out from use. It will always be that way - the tool kit of available UV materials becomes smaller and ink formulating becomes more difficult. Photoinitiators (in particular) are under scrutiny of late.

What will we see at Drupa?
Digital printing has already been the talk of the last 2 Drupa’s where it had come to the forefront of many exhibitor booths, often via very large, flagship, inkjet printing machines. I believe it will be an evolution of this as we have already seen many capability demonstrations and the technology seeds have already been sown. Maybe new markets will come within reach. At Drupa 2016 inkjet was mostly paper based printing but in 2020 we will see more flexible packaging, carton board and more difficult applications for inkjet emerging. I am sure that Drupa will be more of the same but now with more challenging surfaces and applications.

And water-based inkjet will shine - there is certainly a thirst for it!

To contact Phil, email him here.