Using Inkjet Printing with Water-Based Ink for Flexible Packaging Applications

This article, written and sponsored by Michelman, focuses on digital printing, specifically inkjet printing, of flexible packaging.

By Gianluigi Rankin, Global Marketing Manager for Digital Printing, Lori Gobris, Global Marketing Manager for Printing & Packaging, Circular Economy, and Ralph Giammarco, Global Business Development Director

Flexible packaging is defined as a package or container with a shape that can change when filled or closed. The packaging can be paper, plastic film, or foil and will typically take the shape of a pouch, bag, film, lidding, liner, roll stock, sleeve, or wrap. It is used to protect, market, and distribute various products and items in consumer and industrial applications. 

Printing on flexible packaging can be done in various ways, each with its own application suitability, pros, and cons. Those printing methods include flexography, rotogravure, lithography, and digital printing. This article will focus on digital printing, specifically inkjet printing of flexible packaging.

According to Smithers Information Ltd, flexible packaging is a strong growth market reaching an estimated $248.6 billion in 2021, reaching an annual growth rate of 4.1% since 2016. It is forecast to grow at a rate of 3.2% to a value of $291.5 billion in 2026. 

Used in both consumer and industrial applications, industrial packaging, such as shrink film, stretch film, flexible pouches, seal bands, blister or skin packs, and clamshells, currently accounts for a significant percentage of total sales. However, consumer applications are growing faster than industrial.

The largest single consumer market for flexible packaging is food packaging. This application is driven by continued population growth and consumer demand for food in more convenient and smaller packages. Flexible packaging can meet these application demands where rigid alternatives cannot.   

Advances in digital printing are quite literally changing the flexible packaging landscape. According to Smithers, “Traditional, large-scale printers and flexible packaging providers with pouch converting machines are retrofitting those existing systems with digital printing equipment, creating bold new product packaging with their current infrastructure. There are also hybrid setups that combine digital printing and flexographic printing on the same line.”

Interestingly, COVID and employee shortages across most industries also impact how flexible packaging is printed. Printing press operators at traditional printing companies are highly trained and skilled technicians who have mastered their trade over many years. Digital printing, on the other hand, can be learned much more quickly and perfected by individuals with appropriate software training. That difference in the type of “operator” means a much deeper pool of candidates can ultimately operate digital printing presses. This becomes advantageous in an environment where potential new employees can be scarce, especially highly trained traditional press operators.

Unlike label applications, where digital printing has seen substantial growth over the past decade, digital printing is still in its infancy stage in flexible packaging. According to Smithers, “In 2032, digital print output in flexible packaging will be worth about $2.2 billion, capturing a small portion of the total flexible packaging market. This equates to about 20.7 billion A4 pages in 2032. Expected growth rates in A4 pages are 9.3% CAGR between 2022 and 2027 and 7.1% CAGR between 2027 and 2032.”

Smithers goes on to show that in 2032, inkjet will account for 54% of pages in flexible packaging with a 2027 to 2032 CAGR of 8.4%.

There are many benefits and opportunities inherent to digital printing capabilities that align with flexible packaging consumer trends, as well as with brand and producer needs. Small runs, versioning variable data, personalization, quick time to market with new products, less time on press checks and color matching, cost savings, reduced waste, and environmental advantages are all features of digital printing. These can all be applied to flexible packaging applications where there is a rise in private label market share and personalization and proliferation of product SKUs.

Productivity and flexibility are key advantages when considering inkjet technologies for flexible packaging applications. Productivity is a function of print speed and print width. The fastest inkjet production presses today can print at speeds of up to 1,345 ft./min. (410 m/min.), and the desired print width is achieved by adding the right number of inkjet printheads to a page-wide array. While a typical application falls in the 50- to 60-inch range, there are presses for other applications on the market that can print up to 110 inches wide in a single pass. So you can go wider than 30 inches in flexible packaging and easily match the width of the standard wide web converting equipment for analog printing.

This width flexibility helps protect the investment of the converters since they can continue to use their wide web converting equipment and it fills more of a need than narrow web printers.

Inkjet printing technology allows you to design a highly productive press that meets the converting requirements of the converters.

While digital printing and, more specifically, inkjet printing on flexible packaging presents many advantages and benefits, technical challenges must be overcome. Most flexible packaging today uses film, which is a non-porous substrate. With inkjet, you are dealing with a lot of water which cannot be absorbed by the film and needs to be removed from the surface. Dryers are generally used for this purpose, but there is a limit on how much drying can actually be used. If you overheat the film, you run into deformation issues. On the other hand, if you do not dry the ink enough, you will have a negative impact on print quality, lamination bond strength, and the final product itself. So, there is a delicate balance that needs to be achieved.

However, circular economy initiatives are leading many brands to consider paper as an alternative with consumer perception of increased sustainability on paper vs. plastic and single-use and other plastic packaging legislation. Paper is much easier to print using inkjet technologies than film. Paper is a porous substrate and absorbs the water used in the ink. The surface is then easier to dry, and removing the remaining water in the paper is also easier since you do not need to worry about the substrate's deformation. Paper, however, has lower barrier properties, limiting its use in some applications today. Fortunately, new developments in both paper production and barrier coatings designed specifically for paper overcome some of these limitations.

No matter what substrate you use, you will want to use a primer to achieve the highest print quality. In the case of films and coated papers, primers are necessary to keep the ink pigments in place while the water is removed and the film goes through the subsequent finishing and converting steps. Primers on uncoated papers keep the pigments closer to the surface of the substrate and provide a more vibrant print image.

There are numerous environmental reasons to transition to paper-based flexible packaging. Paper is, of course, derived from natural resources. It’s more biodegradable than alternatives, and since it can be re-pulped, it’s highly recyclable. Thanks to its efficiency in product to packaging ratios, flexible packaging ultimately results in less consumer waste being sent to landfills. 

As brand owners work to create packaging that engages and connects with consumers, flexible packaging offers the ability to balance sustainability, protection, and the convenience that consumers demand. Flexible packaging addresses these key industry drivers through material and resource efficiency, increased shelf life that prevents food waste, high product-to-packaging ratio, transportation benefits due to light-weighting, and reduced materials to landfill.

Michelman experts develop new materials and coatings with a “sustainability first” approach, prioritizing health and safety during use and circularity at end of life. Our next-generation primers, barrier coatings, topcoats, and heat seal coatings offer increased functionality while maintaining a sustainable package, with opportunities to reduce waste, provide product protection, and use fewer raw materials.

Michelman's water-based Michem® Flex packaging family is a complete system of enabling technologies that allow for environmentally friendly and sustainable packaging solutions. Our coatings are developed to work together but also flexible enough to work independently with existing coating systems to create superior packaging for food, medical, and consumer goods applications.