Protective Overprint Varnish (OPV) Topcoats

Protective overprint varnishes, used on printed graphics applications, such as magazines, were historically some of the first UV/light curable products. Due to the excellent abrasion, scratch, and wear resistance that UV/light curable products offer, they are also often used as protective topcoats.

Protective Overprint Varnish Topcoats

One downside of UV curable coatings is the difficulty to regulate the level of gloss. Unlike solvent or water based coatings, there is no volatile ingredient loss and, therefore, no matrix shrinkage, which pushes the gloss reducing ingredients to the top of the coating surface. As a result, UV matte coatings tend to be loaded with gloss reducing ingredients leading to viscosity increase, flow reduction, and application difficulties.

Spectra scientists were able to develop an ultramatte acrylate based (one part) coating for plastic and paper substrates that combine very low gloss levels with no viscosity penalty, allowing for application using a regular roll or curtain coating equipment.