Energy curable technologies such as UV and EB have successfully gained prominence in a wide variety of graphic arts and coatings markets. The ability to instantly cure the ink or coating with little to no volatile organic compounds (VOCs) as well as impart excellent resistance properties, has made UV and EB a choice for numerous applications.

The field of printed electronics is another area of interest for UV and EB formulators, but that interest has remained somewhat limited. In an effort to bring attention to the potential usage of UV and EB in printed electronics, RadTech International North America recently held uv.eb WEST 2011, its two-day conference and exhibition, in Santa Clara, CA/USA. The conference was successful, as more than 240 attendees heard talks ranging from printed electronics to the capabilities of energy curing and determining the applied cost of coatings.

The Cost of Coatings

From the perspective of paint and coatings manufacturers, uv.eb WEST 2011 had a pair of informative talks presented by Bob Richardson, chief engineer of Jabil Electronics, Green Point Division, which is a major user of coatings.
 
In his discussion on “Disconnects in the Supply Chain,” Richardson outlined the approach that Jabil Group takes with its suppliers. A contract manufacturer for the electronics industry, Jabil Group had $13.4 billion in sales in 2010, supplying Motorola, Nokia, Sony, Samsung and Research in Motion, among others.

“We are one of the world’s biggest job shops, but we don’t put our label on anything,” Richardson said. “The OEMs we deal with want value and 100 percent certainty they will not have any problems in the field. We pay our suppliers well over market value because of our huge need for support.”

Richardson said that Jabil Group has 42 paint lines, including 28 in China. All told, Richardson’s division buys about $150 million worth of coatings annually. He estimated that the entire company buys nearly a $1 billion in coatings each year. In terms of UV, all of the hard coat and 90 percent of the finish coat is UV cured.

Among the paint and coatings companies that meet Jabil’s requirements are AkzoNobel, PPG, Red Spot, Fujikura, Cashew, Becker’s and BASF, and very few others, Richardson noted.

He added that coatings suppliers must show how they add value in terms of costs, processing time and enhanced marketing ability. They must also be able to work on existing lines or use equipment that can be inserted into an existing line, and must be available globally.
 
Richardson’s second talk, “How to Truly Calculate the Cost of a Coating,” looked at the economics of coatings. He noted that first and foremost, quality must be a given, and determining applied costs is essential. “With quality as a given, what do we fall back on?” Richardson asked. “Math, chemistry and physics. That is what paint is all about.

“The great myth is that the cost per gallon is more than just a number,” Richardson added. “It is only part of the picture.”

There are a number of factors involved. Cost per gallon, volume of solids, transfer efficiency, film thickness and production costs, including processing, labor, waste disposal and inventory, all are part of the overall equation. For example, higher volume solids materials provide more coverage, while reducing costs of freight, handling and storage. Even if the product costs more per gallon, the applied cost might be less for the higher volume solids than for a less expensive alternative.

“If you don’t know your costs, you are guessing at profits,” Richardson concluded.

Conference Sessions

The first day’s talks were divided into two pairs of concurrent sessions. Session One covered Coatings - Functional, Films, Light Management, and was moderated by Mike Idacavage of Cytec. Doug DeLong of DoctorUV.com led off the session with his talk on “Reducing Flexible Electronics and Solar Module Costs with Atmospheric Plasma Surface Modification.”

“Solar is a technology of the future,” DeLong said. “Successful commercialization of low cost, high efficiency fabrications is highly dependent upon fabrication methods which employ continuous processing techniques.”

In his talk on “Photonic Curing Sintering for Metal Inks on Films,” Stan Farnsworth of NovaCentrix said that scaling up to production is now becoming more important. “The challenge is to scale up to square meters and kilometers,” Farnsworth said. “Printed electronics is at the tipping point toward manufacturing.”

Farnsworth noted that screen inks are typically laid down in a thicker layer, thus offering the best conductivity, but require a higher processing temperature.

Nanotechnology ink costs more, but can be processed at a lower temperature. As for substrate, PET and paper’s costs are favorable, but the temperature processing is not there. The NovaCentrix PulseForge tools release an intense pulse of light, which does not heat the substrates.

“Low temperature materials such as cellulose and PET are now feasible substrates for high-performance printed electronics applications,” Farnsworth added.

Fusion UV’s Kazuo Ashikaga next discussed, “The Challenges Associated with Micro Embossed UV Coatings for the Optical Film Applications.” He was followed by Teresa Ramos of Cambrios Technologies, who discussed, “Cambrios’ ClearOhm Transparent Conductor: A Higher Performing, Wet Processable Alternative to Conductive Oxides.”

Cambrios Technologies’s ClearOhm transparent conductors are used in a wide range of products, including touch screens, LCDs, thin film photovoltaics and organic LEDs. The company uses slot die coatings and gravure, after which the transistors pass through a UV curing station.

“Ink and UV clearcoat materials have been developed and demonstrated good carrier performance on our 1.3 meter wide line,” Ramos said. “Our cost versus indium tin oxide is half the price.”

Cytec’s Marcus Hutchins then analyzed “Energy Curable Coatings for Electronics.” He noted that energy curing’s value proposition is found in its faster line speed, curing in milliseconds; 100 percent solids, thus releasing no VOCs; and its resistance properties.

Potential markets for UV and EB curing includes products that require scratch resistant coatings, haptic feel, pressure sensitive adhesives, or easy-to-clean applications.

“Energy curable technology is a well understood science with significant growth opportunity,” Hutchins said. “There are a wide variety of different base chemistries available to the formulator that can be formulated to have a number of performance properties.”

Session Two covered Adhesives, Potting Compounds, Dielectrics, and was moderated by Michael Dvorchak of Bayer MaterialScience.

“High Throughput, Low Heat UV Curing for Inks and Adhesives” was the topic of the talk given by Mick O’Brien of Lumen Dynamics Group, Inc., who examined UV LED curing. Glenn Alers of the University of California, Santa Cruz, focused on “Reliability of Encapsulation Materials for Photovoltaic Modules.” He offered insights into key reasons for failure of encapsulation for various PV technologies. “UV/EB Laminating Adhesives for Stabilized Films,” by Joshua Oliver of Sartomer USA, LLC, covered curing through PEN and stabilized PET.

Inks, Paste, Dielectric Coatings was the focus of Session Three, moderated by Lonnie Murphy of Fusion UV Systems, Inc. Eugene Siztmann of BASF led off with “New Cationic Photoinitiators for Electronics, Printing and Coatings Applications.” “Printing and electronics rely on cationically curable materials for enhanced performance,” Sitzmann noted, covering recent developments in cationic photoinitiators from BASF for the North American market. Tim Luong of Fujifilm Dimatix, Inc. followed with his talk on “An Efficient, Compact and Easy-to-Use Customizable Inkjet UV Curing System for Dimatix Materials Printers.”
 
JSR Micro, Kentaro Goto of JSR Micro covered “Review of Photoresist.” Goto looked at the past, present and future of photoresists, and where UV curing plays a role.

Mark Tilley of Unidym covered “How Printable Transparent Conductors will Enable Roll-to-Roll Processing of Visual Displays.” Unidym manufactures carbon nanotube-based inks and films for touch screens, eReaders, LCDs, OLEDs, LEDs and PV, and uses gravure and slot die processes. The company also occasionally uses UV topcoat.

“We are really excited about flexible displays,” Tilley noted.

Rainer Neeff of EMD Chemicals discussed “Merck’s Reactive Liquid Crystal Materials for Brightness Enhancement Films & Optically Anisotropic Patterned Retarders.” Neeff noted that Reactive Mesogens (RM) are liquid crystalline materials that can be permanently fixed in the liquid crystal phase by polymerization, and can be tailored for UV curing.

Session Four, moderated by Michael Kelly of Allied PhotoChemical, Inc., covered Coatings - Assembly, Final Products.” Richardson led off with his talk on “Disconnects in the Supply Chain.” Mikyong Yoo of Artificial Muscle followed with “UV Cured Materials for EAP Actuators.”

Acquired by Bayer MaterialScience in 2010, Artificial Muscle has developed electroactive polymers (EAP), which provide haptic feel to electronic systems such as touch screens.
 
“Our Baysol Reflex EAP actuator consists of functional layers that are screen printed, which is the most cost-competitive volume manufacturing. There are 17 layers, and UV curing is used on some processes, thermal curing on others,” Yoo noted. “UV reduces the thermal load and protects hat sensitive films. It offers high line speed and reduced manufacturing time, and reduces manufacturing space compared to a thermal oven. There are also energy savings and longer pot life.

Roger Cayton of Nanophase Technologies Corporation covered “Nano- and Sub-Micron Alumina for Scratch Resistant Coatings.”
 
“Highly concentrated dispersions of alumina nanoparticles, ranging from 20 to 800 nm, can be prepared directly in acrylate monomer,” Cayton said. “The dispersions are stable and compatible with UV-cured coating formulations. A combination of nanoparticle expertise and application knowledge allows a step-changing performance in UV-cured coatings to be realized.”

“Creating Success – From R&D to Commercialization, a Machine Builder’s Perspective,” presented by Adam Zielenski of ConQuip, Inc., closed the session by noting the growth of UV curing in flexible forms. Zielenski also discussed methods for applying UV coatings, including slot die coating, gravure and roll coating.

PE, PV and UV/EB

The March 9 session featured morning talks centered around printed electronics, the solar market and UV/EB’s capabilities. Raghu Das, CEO of IDTechEx, analyzed “Printed Electronics” in his keynote talk, discussing key markets such as OLEDs, PV, transistors, sensors, lighting and more. One key point Das made was that printing adds value, such as in cost, the ability to produce large area electronics such as LCD billboard displays and compatibility with low cost flexible substrates.

“Printed electronics will tackle many needs,” Das said. “It will make hundreds of billions of disposable circuits possible. Printed electronics is applicable to large area form factors, particularly relevant to displays, photovoltaics and large sensor arrays. It is applicable to creating very simple devices with few transistors that need to be made in high volumes, and enables new form factors thanks to new substrates being used with electronics for the first time.

“UV’s opportunity is its ability to enable the big markets by being compatible with low cost flexible substrates,” Das added. “Adhesives, protective coatings, barrier films and active layers, e.g., conductive transparent layers and even semiconductors could be UV cured.”

Jason Eckstein of Lux Research, Inc. followed with “Challenges and Opportunities for Materials Developers in the Solar Market.” He provided an overview of the solar market, focusing on the growth of thin film technologies.

UV/EB was the topic of next talk, as David Harbourne of Fusion UV Systems, Inc. presented “UV/EB Curing: The Current Status & Future Opportunities,” an overview of the North American market. Harbourne noted that UV and EB are growing at 1 9 percent annual rate, and sees opportunities in flexible electronics markets such as rollable digital readers, flat panel displays, wearable displays and flexible memory chips. Richardson then discussed “How to Truly Calculate the Cost of a Coating.”
 
UV/EB equipment was the focus of the final two talks. Dr. Stephen Lapin of PCT Engineered Systems discussed “Introduction to UV/EB Equipment Selection,” a comparison between UV and EB.
“UV and EB are complementary, not competing technologies,” Dr. Lapin said. “Selection of UV or EB should be based on the best fit for the process and application.”

Jim Raymont of EIT Instrument Markets covered “Controlling The UV Process: Measurement & Monitoring Options.”
 
“Understand the capabilities and limitations of Your Instrument and measurement strategy,” Raymont noted. ‘Waiting to monitor/measure UV until after you have a problem is guaranteed to cost you time and money.”

The conference closed with a UV/EB Chemistry Short Course, an introductory course to the basic chemistry of UV/EB curable formulations.

RadTech’s leaders and the conference’s organizers were very happy with the conference and the attendance, which far exceeded their expectations both in terms of number of people as well as new attendees.

“This program shows that there is a lot of interest in our technology,” Harbourne said. “Thee were a lot of people here who we haven’t seen before at our conferences. When I arrived at registration, I recognized few names and even fewer companies. We did about double of what we expected. We found the attendees had much interest in the presentations.”

“This has been outstanding,” Idacavage said. “It far exceeded our expectations in attendance. We had a large number of people come to RadTech for the first time, which shows that UV and EB can be an enabling tool for electronics.”