UV LED

One of the technologies to watch real close is the quickly emerging use of UV LED for inks, adhesives, and coatings. At the TLMI Technical Conference early in September, Tom Hammer, product manager, narrow web for North America at Flint Group, and Greg Palm, executive VP new business development, covered the emerging technology's benefits and reviewed some beta site implementations.

UV LED (light emitting diode) curing is based on solid-state technology, which brings along inherent benefits versus the traditional mercury vapor systems that are currently in widespread use. LED systems are more energy efficient, producing faster cures and higher productivity; are instant on/off; and offer longer lifetimes and lower maintenance. Because of its energy efficiency, and partly the result of its very narrow output at 395 nm, the curing takes place with much less peripheral heat, which allows UV curing with heat-sensitive substrates, including popular shrink sleeve labels. The use of UV LED does require that inks, adhesives, and coatings are specifically formulated for this 395 nm spectrum.

Hammer and Palm both reported on a successful 4-month beta test that ran 24/7 late last year. A range of applications included:
• A 2-mil clear BOPP label using opaque white, black, and coating that ran up to 750 fpm
• A 54 lb semi-gloss substrate running four process colors, four spot PMS colors, and a coating (9 stations)
• A 6-color shrink label (64 percent shrink PVC) that ran with no heat management (no chill rollers); no distortion was evident at higher press speeds
• An 8-color shrink label that ran at up to 400 fpm
• Laminated films ranging from 0.75 mils to 2.0 mils using LED adhesives with press speeds to 400 fpm
• Direct thermal stock with 2 to 4 UV LED spot colors

UV LED technology has many benefits to offer label and package printers and converters and that's why it's getting lots of attention.