Principle of laser-drying

Rylenes XXV represent a further interesting class of NIR-dyes [YUA 13,SCH 08]. The substituents Rl and R2 influence the solubility of these neutral compounds. Nevertheless, these chromophores sensitively change their absorption spectra upon change of the surrounding, which was discussed as a result of H-aggregation [YUA 13]. 

Polymethine dyes exhibiting the general struetures XXVIa-c were extensively studied as NIR-absorber dyes [ERN 07]. They possess a reasonable absorption at 980 nm and the solubility varies by change of the substituents at the dye cation and the nature of the anion. Anions derived from sulfonic acids, i.e. Ci2H25-Ph-S03 , have brought the best success in these studies [ERN 13, ERN 07]. Table 7.6 summarizes some spectral data of the dyes XXIV-XXVI. 

The laser drying of offset printing plates has received some intention in printing market. This new drying technique was already successfully tested in the market. There exist enough possibilities to expand this technique particular for chemical drying. Furthermore, the extensive R D work in the 

PCAB 99] Kabatc J., Kucybala Z., Pietrzak M. et al, Free radical polymerization initiated via photoinduced intermolecular electron transfer process kinetic study . Polymer, vol. 40, p. 735, 1999. 

While the discussion of dyes is central in this chapter, we will begin with a brief review of some recent achievements made regarding the study of photopolymer materials. 

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