As adhesives become more prevalent and accepted in industry, the more varied the formulations have become—and by corollary, the more diverse the curing mechanisms. One curing method that has gained traction is radiation curing—specifically, using the ultraviolet (UV) spectrum to provide photonic energy that triggers a fast reaction called photopolymerization. In this particular case, the adhesives contain a photo initiator, which, when exposed to UV light, generates a reactive species that starts to create C-C bonds; the higher the percentage of C-C bonds, the better the “cure.”
As UV/light emitting diode (LED) curing is very fast, it lends itself well to continuous production processes, such as converting reels of material through a machine that applies a pressure-sensitive adhesive for tapes. The same principle applies for printing on a reel of material and is widely used in graphic arts production.