Smithers Study Reveals Challenges for Water-Based Flexographic Printing

Environmental considerations are increasingly important across the print industry.

One of the most immediate changes a print service provider can make is to switch from solvent- to water-based (aqueous) inks, but this is not without challenges.

In flexography, the sophistication of contemporary solvent-based systems, costs and compatibility with polymer substrates will limit the adoption of water-based systems in flexible packaging work. Although, aqueous flexography will continue to be adopted in applications that use fiber media.

The current state of the art and future direction for this evolutionary trend is examined in a recently published study, The Future of Water-Based vs. Solvent Printing to 2027 from Smithers.

Solvent & Water

In 2022, just over 3 billion tons of printing inks were consumed worldwide, according to Smithers’ data projections. Of these, 981,400 tons were solvent-based—almost double the volume for water-based inks. The largest segment—1.17 million tons—is for traditional oil-based inks, although these are largely confined to litho presses in declining markets. A further 401,200 tons of radiation curing inks were used, mainly on UV curing systems.

The market shares by value are more indicative of the future direction of the market. Sales of water-based inks in 2022 just topped $5 billion while solvent inks sales totaled $7.67 billion, reflecting the premium increasingly available for functional aqueous print technology.

Structural changes in the print market, especially the decline of many traditional publication markets, means ink sales by value will increase at a 1.8 percent compound annual growth rate (CAGR) through to 2027. Demand for solvent inks will continue to be sluggish 1.3 percent CAGR, but significantly higher at 5.6 percent for water-based inks.

Flexographic Ink Markets

Flexography is the analog print process with the best market outlook post-COVID. This is due to its wide use in packaging work and more limited share of commercial, advertising and publication work. The volume of flexographic work means it already enjoys the largest share of overall water-based ink sales—around 87 percent by volume in 2022—although there are also significant markets for inkjet and gravure.

Flexography will remain the key market for water-based inks into the future, by volume. Developments for flexographic printing will be evolutionary rather than revolutionary, however. Most of cutting-edge research for aqueous printing will now focus on higher-value inkjet work. Recent innovations in water-based inkjet printing reaching the market include Xaar’s Aquinox printhead and Screen’s new Truepress PAC520P flexible packaging press.

In 2022, Smithers projects a total of 949,500 tons of ink were used on flexographic presses worldwide. Over 80 percent of this was on packaging substrates—flexibles (55.3 percent), labels (9.2 percent), corrugated (8.6 percent) and folding cartons (7.2 percent).

The transition to water-based printing is already well underway in other smaller commercial and publishing print segments. Post-COVID, these markets have low growth prospects. And the enthusiasm for greener printing will be more than countered by the anticipated growth in demand for flexible packaging, where solvent inks remain the preferred technology. Across all flexographic applications, solvent inks totaled 387,500 tons in 2022, and are forecast to increase at a 3.4 percent CAGR through to 2027.

Water-based flexographic inks are gaining some traction in flexible packaging and are widely used for publishing and commercial printing, as well as for labels and corrugated. In 2022, a total of 426,300 tons of water-based inks were used in flexographic pressrooms; the rate of adoption is expected to slow, with this ink technology in flexography forecast to have a 2.1 percent CAGR through to 2027.

The other major ink option for flexography is UV curing, with a total of 135,700 tons consumed in 2022. This is now established as the dominant technology for narrow web presses used in labels and is now reaching into lower-volume flexible packaging work, such as sleeves and pouches.
Technical Barriers

There are a number of technical barriers that are restraining the greater use of water-based print on flexographic presses. First, they are more expensive than solvent ink systems, which are well established in the market.

In the contemporary market, ink makers are having to compensate for raw material shortages and enduring supply chain disruption. This is leading to price increases for all ink types. The market for flexographic inks is already very competitive, meaning there is less space for manufacturers to absorb these costs themselves, and instead they are being passed on to customers. The spike in pricing seen in 2020-2022 is expected to recede slowly, as the market adjusts to new geopolitical realities.

Still, in the medium term the focus for aqueous print technology will be to tailor adoption to those segments where there is a genuine enthusiasm for greener printing.

Furthermore, solvent-based flexographic print is well established in the core market for flexible packaging with formulations offered with a range of specific end-use characteristics and performance properties particularly for printing onto filmic print media. This will only be displaced as and where aqueous ink systems can match such performance.

Water-based printing does have the advantage of not releasing volatile organic compounds (VOCs) into the pressroom, but this threat is now being countered by a new generation of solvent abatement strategies using cryogenic recovery, filtration or thermal oxidation. These are letting flexible packaging converters meet many of the environmental requirements of regional or national legislators.

Critically, drying time for water-based inks is longer than for either UV curing or solvent print, which is especially problematic when trying to form a stable ink film on a polymer substrate. This is the principal reason aqueous flexography is, and will remain, limited to those applications that use more absorbent fiber media—such as wrapping papers, paper sacks, napkins, foodservice ware and newspapers. It will be possible to improve drying times for water-based inks, but most such technology is either bulky, extending the length of the print line, or energy-intensive and hence costly.

Where gains will come for water-based inks are where and if brand owners choose to transition from plastic flexibles to paper-based formats. With flexible plastics having the worst collection and recovery statistics of any packaging type, many papermakers are producing substrates to capitalize on this green packaging trends. They are releasing new functional paper materials, including translucent and barrier paper grades, but adoption is largely confined to smaller artisan brands whose short printruns can be managed on inkjet presses.

On plastic packaging media, drying time for water-based will remain a major inhibitor, except for work where presses are run well below their top speeds. At lower printruns, UV flexography is a viable alternative. One competitive advantage for water-based systems here is that it is easier to obtain regulatory approval for use in food contact. There is still residual concern, especially in Europe, over the migration of photoinitiators and other substances from incompletely UV-cured ink films.

One growth segment will come from corrugated, especially the need for ink sets to print detailed images on corrugated board instead of the basic postprint systems currently in use. However, prices can be very low, driven by the size and negotiating ability of some of the large converters operating in these spaces.

Facts & Findings

• In 2022, 3 billion tons of printing inks were consumed worldwide
• 981,400 tons were solvent-based, double the volume for water-based
• Sales of water-based inks in 2022 topped $5 billion
• Solvent inks sales totaled $7.7 billion
• To 2027, demand for solvent inks will continue to be a sluggish 1.3 percent compound annual growth rate, but significantly higher at 5.6 percent for water-based inks
• Flexography will remain the key market for water-based inks into the future. In 2022, it already enjoys the largest share of overall water-based ink sales, at 87 percent by volume
• In 2022, 949,500 tons of ink were used on flexographic presses worldwide