| abstract |
Very low gloss finishes are attained in dark colored (e.g., black), radiation curable coatings by inclusion of black silica pigment in a composition containing a radiation curable binder resin (e.g., polyacrylate) and a photoinitiator (preferably alkoxy substituted acetophonones). Also useful are viscosity control polymers of higher molecular weight than the binder resin and compatible therewith, such as acrylated acrylics. The coating is first exposed to ionizing radiation (e.g., electron beam) in air, then exposed to actinic radiation (ultraviolet light) in an essentially inert atmosphere. The low gloss is achieved by a combination of pigment selection and a fine, uniform surface wrinkling effect. |