Advances in UV curable coatings using photolatent additives

摘要

Recent advances in photolatent additives for UV curing helps in doing away with the shortcomings of conventional UV curable systems. There are intrinsic limitations associated with radical photo polymerization such as oxygen inhibition, insufficient curing of shadow areas, poor coating of thick and highly pigmented coating, lack of adhesion on certain substrate. All these limitations can be overcome by recent development using photolatent additives and thus support the expansion of the scope of UV curing technology in industrial and automotive application. Photolatent bases are stable and inactive in the dark when incorporated in coating systems, but efficiently releases tertiary amines or amidines on irradiation with UV or daylight. Variety of formulation can be cross/inked by photolatent base catalyst. The new technology allows adjustable speed UV and daylight curing, as well as post cure of poorly exposed and shadow areas on three dimensional objects. It also extends the pot life of 2K systems, which have to be mixed prior to the application. Another exciting application of photolatent effect is the addition of pleasant smell in paint using photolatent fragrance additives. Also photo induced effect can be obtained by using Photolatent colorants.