Sensitometric parameters of photopolymer plates used for the production
of flexographic printing forms by the digital laser-photochemical method
Polimery 2010, No 11-12, 863
The sensitometric parameters of selected photopolymer plates designated for use in the production of flexographic forms by the digital laser-photochemical method have been determined. Characteristic curves for the selected plates indicating the dependence of the thickness (d) of the hardened photosensitive layer as a function of the logarithm of irradiation (log H) were obtained (Fig. 2). The relative photosensitivity threshold (S0) and the coefficient (W) of the rate of photohardening (photocrosslinking) of the layer were evaluated (Tables 1, 2). The linear regression equation method, which describes the linear fragments of the obtained curves, was applied to determine the sensitometric parameters of these photopolymer plates as well as the optimal period of preliminary exposure required to achieve an appropriate depth of relief of the flexographic printing form (Fig.1). Moreover, this method allows for a quantitative comparison of different photopolymer plates, taking into consideration their sensitometric parameters, and the determination of the optimal preliminary exposure duration for a large number of different plates after a change either of the required relief depth of the flexographic printing form or of the photopolymer plate itself. The accumulated data can serve as an essential tool in selecting the most suitable parameters and controlling the preliminary irradiation process of the polymeric plates.
Keywords: photopolymer plates, sensitometric parameters, photosensitivity, flexographic printing plates, digital laser-photochemical method
Sensitometric parameters of photopolymer plates used for the production of flexographic printing forms by the digital laser-photochemical method