Getting Better All the Time

Improved raw materials help spur growth of energy-curable inks.

LUCK IS WINNING the lottery with a million-to-one chance, or catching the winning homerun ball in the deciding game of the World Series. But luck rarely has anything to do with success, as is the case with energy-curable inks, which have been increasing in demand thanks to the results of a lot of money, time, and energy spent in R&D.

In the last few years, use of ultra-violet (UV) and electron beam (EB) inks has continued to grow with the introduction of new curing technologies, better inks, and lower costs for both. UV inks have seen recent, significant growth mostly because of UV hybrid inks, said Don Duncan, Wikoff Color Corp.'s director of research. EB ink is also growing. When once an EB curing unit was cost- and size-prohibitive, EB technology is now at the least a feasible investment. Put it together and the result is a rising demand for UV and EB inks.

Duncan said, "With an improving economy, more printers will be willing to make the capital investment in one of these energy-curing technologies in order to capitalize on the instant-dry, green, and print performance properties of UV and EB."

Benefits abound with energy-cured inks. There's no loss of solvent or issues such as ink drying too fast or too slow like printers have with solvent inks, said Zubair Khan, Environmental Inks & Coatings (EIC) technical business manager of UV products. Also, he said, "There's no pH drift or viscosity build-up [that's] associated with water inks. The on-press ink stability of UV inks is excellent."

While ink suppliers and equipment manufacturers have been busy bettering their products, raw material providers have been too.

Basic improvements

UV and EB inks are made up of several components that add color to the ink, or enhance its adhesion and curing properties. It's in these raw materials where many of the newest developments in curable inks have occurred.

Pigments: Pigments—which give ink its color—used in UV and EB inks have changed with demand. Ink vendors created curable formulations of pearlescent, fluorescent, and other specialty inks in response to consumer product companies that wanted to make their product packaging standout on store shelves. However, said Len DiLeo, Kohl & Madden manager of UV technology, "The cost of many of these specialty products will limit their growth and the demand will be for other innovations in security and product differentiation."

Choices of pigments for specialty inks have increased, but so have pigment options in general. "Proper pigment choices are harder to make due to so many products from so many suppliers, but we now have sources for most any pigment application needed," said Ed Dedman, business manager for SICPA North America's Narrow Web & Energy Curable Group. "We are constantly getting new raw materials from our suppliers that allow us to increase pigment strength while maintaining low viscosity. This lets the printer use higher line anilox rolls, thereby reducing ink consumption."

Oligomers: Oligomers are binder components of UV and EB inks, which are especially helpful in binding inks to hard-to-adhere-to substrates like film.

Some oligomers also assist in the dispersion of ink pigments, Duncan said. "Some curable oligomers that are better at dispersing pigments are coming on the market," he said. "This will allow formulators more latitude to improve on-press lithographic performance of inks."

Photoinitiators: Found only in UV inks, photoinitiators are needed for cross-linking (curing) of these inks. Some of the new photoinitiators available to ink vendors are more efficient and faster curing, Duncan said. "This will help give more reliable curing and enable faster press speeds," he said.

These advancements in raw materials, as well as developments in curing equipment, have improved ink capabilities, and have helped drop the price of energy-curable inks for the past few years. However, prices are on the rebound due to a worldwide shortage of acrylic acid, the backbone of most ink and coating raw materials, said Kurt Hudson, Water Ink Technologies general manger of UV Products. Since mid-May, ink vendors have been receiving notice from their raw material suppliers that prices of resins, monomers, oligomers, and other raw materials will be increasing dramatically, Hudson said.

SICPA was recently notified of the increase. "It remains to be seen at this point how much [the price] will increase, but we've been told to expect this as only the first round, with possibly more to follow," Dedman said. "The increase was somewhat unexpected, and we're not sure yet how it will affect our pricing, if at all."

The rising price of oil only further compounds the acrylic acid shortage, said Bill Bayer, business manager of Surface Specialties. "Raw materials are derived from oil and they're all increasing [in price] right now," Bayer said. "As raw material prices increase, companies are pressured to pass those costs on to customers. There was a time when companies were able to absorb price changes, but there's little capacity for that now."

And yet, despite the uncertainty this situation creates for ink manufacturers, Hudson anticipates growth of Water Ink Technologies' UV products to be about 25 percent over the next year. "There's that much demand for it," he said.

Innovations

Prices may be uncertain in the ink and coating markets, but more and more innovations are hitting the marketplace that are well worth the money. One such breakthrough is Sun Chemical's WetFlex™, an ink system designed for the curing process, specifically EB, on a central impression (CI) flexographic press. Sun Chemical developed WetFlex with the help of a CI flexo press from Ko-Pack and an EB curing unit by Energy Sciences Inc. (ESI).

WetFlex lets a printer wet trap energy-curable inks, coatings, and adhesives without the use of interstation drying, which is customary with a conventional CI press. With WetFlex, print quality is high and, because of its instant-cure capabilities, the press can be run up to speeds of 1,000 fpm, said Mike McGovern, director of sales and marketing for all Energy Curable Products at Sun Chemical. WetFlex also increases color strength and allows for increased line graphics, he said.

Another innovation for energy-curable inks and coatings is FlexCure™, a self-initiating resin technology platform created by Ashland Inc. Ashland recently introduced FlexCure products at RadTech e/5, a well-attended UV and EB technology event held in Charlotte, N.C. Ashland and the UVTechnology and Mark Andy divisions of Mark Andy Corp. produced printed samples demonstrating some of the product's capabilities.

FlexCure requires little or no photoinitiators, minimizing the odor or yellowing typically caused by photoinitiators, said Matthew Sheridan, Ashland Specialty Chemical product manager. The FlexCure technology offers a great deal of flexibility in its coating and ink applications, including packaging substrates, wood and more. FlexCure resins for inks also provide excellent pigment dispersion and color development, Sheridan said.

Future expectations

All of these developments in UV and EB have piqued the interest of many package printers. According to Don Matthiesen, marketing director of EIC, UV ink sales are growing faster than water inks for the same applications.

EB ink sales are also expected to grow as the cost of the curing equipment further decreases. In the meantime, the future is still bright for energy-curable inks.

"This demand continues to grow as printers realize the advantages they are gaining from the use of UV and EB technology," DiLeo said. "The need for the printer to deliver product to his customer in a timely fashion and the ability to respond to new business will continue to increase this market."

By Kate Sharon - Associate Editor