engleski

Functional model of photopolymer printing plate production process

Characterization of the effects of UVA and UVC exposures in the post-treatment process of photopolymer flexographic printing plate production was performed by various measurementand- analysis methods. Samples used in this research were solvent-washable and waterwashable Computer to Plate (CtP), Laser Ablated Mask Layer (LAMS) flexographic printing plates. Analysis of the chemical, thermal, mechanical and surface properties of photopolymer samples was performed in order to define and quantify the influence of the post-treatment process on the properties of printing plates and corresponding prints. Chemical changes in the material were analysed by means of Fourier transform infrared spectroscopy – attenuated total reflectance method, energy dispersive X-ray spectroscopy and swelling experiments. Thermal analysis (differential scanning calorimetry and thermogravimetric analysis) displayed the influence of the duration of post-treatments on the thermal stability and degradation process of the material, as well as the influence on the crosslinking completion. Mechanical analysis provided the information about the changes in hardness of the printing plate due to the posttreatment process. Surface properties of the photopolymer printing plate samples were analysed by calculating the components of surface free energy and roughness parameters. Obtained results were integrated via correlations, as well as least squares fitting and neural network modelling in order to define the functional model of flexographic printing plate production in relation to influencing parameters in the definition of printing plate’s properties in the reproduction process. Prints obtained by UVA and UVC post-treated printing plates displayed significant changes in ink layer thickness and the deformation of fine lines on the prints, as well as the changes in optical density and surface coverage in low and high coverage areas. Results obtained in this research proved that UVA and UVC exposures in the post-treatment process of flexographic printing plate production can be used as a simple and quick tool for modelling modify properties of photopolymer material. This modification is useful in adjusting printing plate’s surface and mechanical properties to a specific value, therefore tailoring the flexographic reproduction system for specific applications in conventional and functional printing.

flexography; photopolymer material; UV post-treatment; crosslinking; surface properties; functional printing

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