Influence of Enhanced-V Lamp on the Photo Polymerization Of Cationic UV White Coating

One of the challenging things in the UV-curing industry is the curing of white
pigment coatings. Due to the high absorption of the rutile 2 that covers the UV
spectrum's region from 200 nm to 380 nm (1), photoinitiators in white pigment formulations
can not receive photons from a light source efficiently. As a result, people have the problem
of how to increase the cure speed of white pigment coatings. The Gallium doped V bulb is
usually used in the this field since its spectrum emission of 400-420 nm can match the
absorption spectra of photoinitiators and photosentisizers with long wavelength UV-Vis
absorption. In this paper, we will demonstrate how to make the curing of cationic white
pigment coatings more efficient by replacement of the F600-V bulb with a new En-V bulb
powered by a new platform.

Since 1970's, the microwave powered UV lamps have been used for UV curing.
However, to accelerate the curing speed and obtain higher quality coating products, UV
scientists have been exploring new IJV microwave powered lamp products (Fig. 1). A
microwave powered 308 nm excimer system was developed (2) and it was found that the
new bulbs of H, D and V could be run with enhanced outputs of 30-40% in energy.
Recently, we have investigated the influence of the En-V lamp on the photo polymerization
of cationic UV white coating. Because the energy output of the En-V lamp in the range of
400-450 nm is about 30% higher than standard F600-V (Fig. 2) (3), this improvement should
benefit the white pigment coating.