Dual-cure inks, which can be cured with conventional UV as well as UV LED, are growing in popularity with printers.

Photo courtesy of INX International Ink Co.

Energy-curable inks and coatings have long been an area of growth, as there are numerous advantages that UV and EB curable inks offer, from environmental benefits such as low volatile organic compounds (VOCs) to production advantages such as instant curing.

In recent years, UV LED curing has made significant gains in the market, with retrofitting of presses and new installations of UV LED systems becoming more common.

Jonathan Graunke, VP of UV/EB technology and assistant R&D director for INX International Ink Co., observed that as in years past, growth continues to be driven by food packaging applications, the expansion of UV LED curing systems, and a resurgence of interest in EB curing.

“Also, retrofitting presses is a much simpler process,” Graunke added. “UV lamp manufacturers have developed solutions that allow for the conversion of existing UV systems to LED with existing footprints, making it very cost-effective. It also allows the user to capture energy savings and eliminate mercury UV bulbs from their process.”

Erik Jacob, PMP narrow web portfolio manager for energy-curable ink specialist Zeller+Gmelin, said that the energy-curable ink segment continues to grow, driven by sustainability trends, regulatory pressures and the increasing adoption of UV flexo printing.

He added that the use of UV LED curing continues to expand, leading to more inks being developed for LED curing as well as dual-cure inks that can be cured with both conventional UV and UV LED.

“At Zeller+Gmelin, we see continued strong growth in labels and packaging print applications due to fast curing and improved print quality,” Jacob added. “UV LED technology is experiencing significant growth, outpacing traditional mercury lamp curing. Zeller+Gmelin is expanding its LED-curable portfolios to meet demand.”

“There is a natural progression for ink companies to formulate products that cure both LED and conventional UV,” Graunke said. “UV LED for equipment is becoming the norm. The emergence of power supplies that can run either UV LED or conventional UV adds a lot of versatility.”

Paul Winstanley, VP of technology and product management for Flint Group, noted that energy-curable inks have experienced significant growth, particularly in the narrow web sector.

“This growth can be attributed to their superior performance, productivity and sustainability quality, particularly with the ongoing rise of UV LED technology,” said Winstanley. “These energy-curable inks also offer better print performance across a wider range of substrates compared with water-based flexo inks.”

Winstanley noted that UV LED curing has surged in popularity over the last three years.

“This growth is largely being driven by rising energy costs and a demand for enhanced productivity and sustainability,” said Winstanley. “Narrow web converters now better understand that UV LED is a proven, viable technology that can assist them with reducing cost to print, minimizing waste, and avoiding ozone generation.

“Equipment suppliers confirm this trend, and many manufacturers are responding by offering more UV LED compatible options, enabling printers to adopt this technology more cost-effectively,” added Winstanley. “New UV flexo presses can be equipped with UV LED technology, or existing UV flexo presses can be retrofitted, and dual-cure products, such as Flint Group’s EkoCure range, facilitate seamless integration for both UV LED and conventional UV presses.”

Fabian Köhn, global head of product management, narrow web and sheetfed at Siegwerk, reported that Siegwerk is observing moderate overall growth in the analog energy-curable ink market in the US and Europe, while energy-cured digital inks continue to experience strong growth.

“The transition from UV to LED technology is particularly evident in the narrow web segment,” Köhn noted. “In Asia, the market is highly dynamic, with significant growth in the UV and LED segments, especially in India, which is showing the highest growth rates. New flexographic presses are now predominantly equipped with LED lamps. In the offset segment, printers worldwide are investing in LED technology for commercial printing.

“In Europe, the growth of LED technology was almost exponential in the last three years, so that about a quarter of the market has now converted to LED, mainly driven by high energy costs,” Köhn observed. “Also, in Asia and Latin America, more and more printers are converting to LED technology. In both China and the US, the conversion started earlier, and there has been a high market penetration of LED technology already in the last years.”

T&K Toka, an energy-curable ink specialist, reported seeing significant growth in energy-curable inks.

“The growth of UV LED curable inks has been remarkable, driven by rising energy costs, a global shift toward environmentally friendly solutions, and strong promotion from press and equipment manufacturers,” a T&K Toka spokesperson noted. “Many businesses are adopting UV LED technology due to its advantages, including lower energy consumption, faster curing times, and reduced operating costs. While some markets, such as food packaging, remain cautious about UV curable inks – including UV LED curable inks – overall demand continues to rise, with many printers planning to install new UV LED equipment.”

Dual-Cure Inks Make Gains

A recent development is the proliferation of dual-cure inks, which can be cured both with conventional UV as well as UV LED. This helps with inventory control as well as simplifying production. There have been challenges in formulating these inks, which ink manufacturers have overcome.

“Developing any technology comes with its own unique challenges, and one of the most significant hurdles that ink manufacturers have faced in creating dual-cure inks is achieving optimal cross-linking under both UV and UV LED light sources,” Winstanley said. “Flint Group overcame this issue with the development of a unique proprietary technology, which enables more complete curing under both UV and UV LED lamps.”

Winstanley added that there has been significant interest and growth in the narrow web sector.

“Customers have expressed interest in the improved print quality and characteristics of these inks, leading to higher productivity as well as reduced energy consumption and waste reducing the overall cost of print,” Winstanley observed. “Dual-curing inks also offer higher flexibility and enable a gradual transition to the benefits of LED curing by adopting it unit by unit to ease capital expenditure concerns. Although narrow web remains a stronghold, mid- and wide-web flexo printers are also increasingly adopting these technologies to reduce their costs and carbon emissions.”

“For dual cure, I think customers look to the ink suppliers to make the best recommendations for their specific needs, including cost,” said Graunke. He noted that the biggest challenges are keeping up with the rapidly changing regulatory landscape.

“Brand owners are increasingly requesting that EU regulations be applied to North American formulas,” Graunke added. “This creates challenges as regulations in the US and EU do not always align, and materials may not be legally available for use. Additionally, concepts such as SVHC are not in the US legislation. This adds to the cost and confusion. Overcoming the challenges comes down to education and working with our upstream vendors to place new materials into the North American marketplace.”

“The shift toward dual-cure technology appears to be a natural progression in the market, rather than a trend driven by specific customer demands,” T&K Toka’s spokesperson noted. “As the market evolves, printers are increasingly inquiring about inks that are compatible with UV LED systems. Additionally, some printers who previously used UV curable inks are transitioning from UV lamps to UV LED lamps for energy savings and are now seeking dual-cure inks that work with both UV and UV LED curing systems.”

Jacob said that the biggest challenges in formulating dual-cure inks are achieving balanced reactivity under both UV LED and traditional Hg UV lamps, maintaining cure speed, and ensuring long-term stability.

“The transition from mercury UV to UV LED is accelerating. At Zeller+Gmelin, we have taken advantage of recent advances in photoinitiator chemistry and resin systems, dramatically improving performance,” he noted.

“Customers increasingly favor dual-cure inks for their flexibility, especially in hybrid press setups where LED and conventional UV curing may coexist,” Jacob observed. “They allow printers to transition to LED gradually while maintaining compatibility with existing systems.”

“There is significant interest,” Köhn noted. “For example, Siegwerk’s ink series SICURA Flex Dual Cure, launched in Europe in 2024, has been a great success and is now widely used in the market. In the US, Siegwerk’s ink series SICURA Nutriflex Orbis DC, also launched in 2024, is increasingly used by customers.

“In general, inks that can be cured with LED lamps can also be cured with standard Hg arc lamps and can therefore be classified as dual-cure inks,” Köhn explained. “The primary drawback of LED inks is their substantially higher cost compared to UV inks due to the expensive photoinitiators used. Consequently, dedicated UV inks remain available in the market.

“Dual-cure inks can be considered a second generation of LED inks, where formulation and application experience over the years have led to cost-optimized LED-curable formulations that, in some cases, are cost-neutral compared to standard UV counterparts,” Köhn added. “However, a cost gap generally remains between UV and dual-cure inks, reflected in higher prices.”

Regulatory issues remain at the forefront of the UV industry. Jacob said that regulatory scru tiny on photoinitiators, such as TPO and BPA-based components, continues to impact energy-curable inks.

“European regulations (e.g., REACH, German Ink Ordinance) and North American compliance concerns (e.g., Nestlé guidance, Prop 65) are pushing the industry toward safer alternatives,” Jacob pointed out. “Additionally, recyclability and deinking performance in circular economy initiatives are gaining attention.”

“There are regulatory concerns,” said Köhn. “Two very important photoinitiators, TPO and Irgacure 379, can no longer be used due to product safety reasons, as they were reclassified to CMR 1 and added to the candidate list for SVHC recently. The available alternatives are more costly and often less efficient, resulting in a higher percentage in the formulation and overall, in higher ink costs.”

Flint Group’s Winstanley observed that regulatory compliance is a key area of focus due to an evolving framework governing sustainability and safety, as the ingredients that can be used in an energy-curable ink are constantly evolving.

“Printers and converters are seeking certainty over which energy-curable ink products they can use for printing indirect food contact packaging,” he noted. “Manufacturers like Flint Group are ideally positioned to support printers with emerging regulatory challenges.”