Influence of UVA Spectral Absorption and Photopermanence on the Weatherability of Laminated Ink Jet Graphics

摘要

Unprotected ink jet graphics fade when exposed to natural or artificial light. Protective laminates containing ultraviolet absorbers (UVAs) are commonly applied over printed surfaces intended for exterior use to slow degradation caused by the ultraviolet component of sunlight. While this affords a level of UV protection, little has been reported about the influence of UVA chemistry on the longevity of coated / laminated prints. This is of relevance because UVAs differ both in their ability to screen specific portions of the UV spectrum and their photopermanence in various media which can limit their efficacy over time. Commercial and experimental UVAs (benzophenones, benzotriazoles, triazines) were incorporated into two different protective coatings which were applied over test prints made using commercial narrow- and wide-format ink jet media / inks and weathered under dry xenon conditions. This paper describes the significant differences in color loss of both dye and pigment-based ink sets that result from the differences in spectral absorption and photopermanence of the various UVAs. The best results were obtained using novel photostable UVAs having broad absorption profiles across the long-wavelength UV region.