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Keywords:

  • coatings;
  • crosslinking;
  • degradation;
  • photopolymerization;
  • radical polymerization

ABSTRACT

During radiation curing, a reactive formulation is converted into a highly crosslinked coating film by means of polymerization reactions. This three-dimensional (3D) network is resistant to external degrading factors as it cannot be undone by any physical–chemical means. In this study, various ultraviolet (UV)-curable ink formulations with different pigments were developed. The behavior of the UV-curable inks was evaluated during UV curing in a photocalorimeter or in a UV tunnel. Inks were exposed to accelerated aging in an accelerated weathering chamber and their physical–chemical properties were investigated. The presence of residual fractions of unreacted species trapped in the 3D network formed during UV curing interferes with the degradation of the main structure during exposure in the weathering chamber. The ink formulations that did not easily absorb UV light increased in gloss and hardness, indicating that residual crosslinking is taking place at the same time that degradation is occurring. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41116.