Inkjet Gets Flexible in Packaging — Part 1

What’s Driving Growth in Flexible Packaging?

Flexible packaging is a large part of the packaging market, with many applications in food, healthcare and cosmetics. Different purveyors of industry statistics value the global market size from $120bn to $160bn –yet all agree that there is a steady growth expected. The Flexible Packaging Association reports that flexible packaging is the second largest packaging segment in the U.S., garnering about 19% share of all packaging with sales of $31 bn in 2018 in the U.S.

Containers in flexible packaging are made from a number of substrates consisting of paper, plastic, aluminium foil, coated paper, film, or a combination of these materials. There are some discussions on the environmental sustainability as most flexible packaging is using plastics. The EU started initiatives to reduce the use of plastics and other countries and organisations are becoming wary as well. Compound materials can reduce the amount of plastic, but still might need some as barrier material. This pressure will give rise to new substrates that avoid plastic altogether or minimise the use. However, it should be mentioned that a flexible packaging uses notably less plastic than a rigid plastic container as alternative.

There are more drivers beyond environmental considerations. As in many packaging markets there is a trend towards shorter runs and more just in time production. The reasons are numerous:

• More fragmented markets

• More brands

• Taking out inventory in the supply chain

• Reacting quickly on market demand

• Promotions

• Test marketing

The Corona virus pandemic especially propelled the desire to order on short notice. Manufacturers find their markets less predictable and need to react quicker. At the same time buyers want to keep less stock. Improvements on the ordering side help as well. Web shops make ordering packaging more efficient for short runs and enable small companies looking into having their own packaging professionally printed.

Which Print Processes are most used in flexible packaging?

Currently, most flexible packaging is printed in flexo, with a smaller share printed in gravure or combination processes. With the right solvents the inks bond well to the substrate and drying/extraction systems can deal with the solvents. Aqueous inks are starting to gain share, requiring an adapted drying system. Central impression cylinder presses have web widths of 1 or 2 metres and can reach web speeds of 600 m/min, accordingly the productivity is very high. Obviously, these presses are neither small nor cheap. In-line flexo presses can be used as well for flexible packaging, with lower speeds and widths, although these are a lot more limited in applications.

As with any analogue process the challenges are getting into smaller runs. Flexo plates are even more complicated to produce and handle than offset plates, the set-up is time consuming and creates waste. Still the pressure for shorter runs is there to move from an annual or semi-annual production purchase and warehouse model to produce what is needed for current production or on-demand. It does make a very compelling case for on-demand packaging printing, however the procurement processes would need to change as a result.

Digital print does have opportunities in flexible packaging. However, the challenges of the materials used has held back adoption of digital print. Inks or toner needs to adhere well, the transport needs to be adapted to a susceptible substrate and so does the drying/fixing.

Another main barrier to entry when it comes to printing flexible packaging is food safety. While flex packs are used for many types of packaging, by far the largest market is in food packaging. UV can be a challenge due to the monomers included. This could be helped by barrier layers or varnishes, since food safety is a complex field however, brand owners prefer to play it safe. Having aqueous inks print and adhere well to the substrates is a challenge and requires more efforts in priming, inks, drying and handling.

Electrophotographic print has made the biggest inroads into flex pack so far with the HP Indigo 20000 Press and the latest version, the HP Indigo 25k. As all HP Indigo presses use liquid toner technology, it offers the quality, sufficient width and ink ranges required for many flexible packages. With 31 m/min in 4C mode the speed is noticeably lower than flexo presses however – and the speed drops further when using more colours.

Where does Inkjet fit in flexible packaging

Inkjet is not new to flexible packaging, but it has been limited to coding and marking so far. Adding variable information is an especially important consideration for those in the food industry, as they must display tracking codes, manufacturing and use-by dates as well as the potential for disclosure language that varies by location.

Full graphics inkjet printing has barely made inroads into flexible packaging. Although flexible packaging is a huge market, the challenges are also big. UV inks are undesirable for food packaging, a major area for flexible packaging. For aqueous inks, being able to print with water on plastics is challenging. Additionally, the print technology needs to connect well to the subsequent finishing steps in laminating and pouch making. Finally, a large gamut is desirable with orange, green and violet for example and offering white can be especially critical.

Still, inkjet can bring much to the table, as in other print application areas, and vendors are stepping up. Inkjet solutions broadly fall into two tiers: low to mid-range solutions and high-volume solutions.

Low to mid-volume solutions target more occasional uses, smaller packs and as a result new entrepreneurial types of users: for example companies with their own print and pack concept as a service. Also, web-to… sales of very short runs can be well served or sample and mock-up making. Devices in this category do not need to run 24/7 to fulfil their business purpose as the value added outweighs the need to fill-up press capacity. Footprint and prices are moderate for these devices, which allows companies to enter the market which do not want to invest heavily into equipment.

High-volume presses are aimed more at today’s flexo press users, although given the limited speed and higher ink costs compared to flexo they will rather be a complement for lower runs than a straightforward flexo replacement. Since the market is moving to shorter runs, these capabilities are getting more important. So far, the short-run market is underserved as print service providers are not able to offer cost efficient short runs and in turn brand owners adapted their supply chain to long runs.

Below is a table of the available or announced high-volume inkjet systems, complemented by the HP Indigo 25k as the most successful digital flexible packaging printing system today (when including the predecessor model 20000).

High-volume inkjet and liquid toner flexible packaging presses

In the second part of this article we give more detail on the low to mid-volume and the high volume presses available or announced.