13 October 2013
Year: 2013
Price: 10.00
Traditional medium pressure mercury lamps produce a wide spectrum of radiation,
including significant emissions in the ultra violet region, specifically UVC, UVB, UVA and
UVV. This spectral breadth allows for the selection of photoinitiator(s) to optimize the
cure of acrylate-based inks, coatings, adhesives, sealants and composites according to
the type and intensity of the light source as well as accounting for species within the
formulation that block and/or absorb UV light (e.g. pigments and fillers).

Unfortunately, these traditional mercury lamps yield 70-75% radiation in non-useful
wavelengths, most notably high energy infrared light that produces significant heat. The
need to keep typical Hg lamps cool requires voluminous airflow, and, thus, additional
energy. Such high air flow eliminates the practicality of using inert gas to improve
surface cure. (Costly inert gas would be constantly exhausted along with cooling air.)

The science of producing a suitably high flux of intense UV photons with light emitting
diodes has made remarkable progress in the past ten years. There are now many
commercial applications for UV/LED technology, allowing for the wider use of heatsensitive
substrates and providing for more economical overall UV-cure by eliminating
huge air handling structure and cost. (When water cooling in high output [>4 W/cm]
systems is figured in, energy savings estimates are as high as 50% versus a typical Hg
lamp system.1,5) Ancillary benefits include a compact, quieter process with “instant
on/off” capability, fewer environmental concerns (i.e. no waste mercury or ozone) and
much longer-lasting UV light sources (20,000 hr. vs. 2000 hr.).
Author: M. Gould | 11 pages

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