Modelling of light-sensitivity of photo-polymerizing materials

Technological recommendations of producers of photo-polymerizing materials (PPM) often suggest defining the duration of irradiation or the size of exposure in an experimental way using the specially developed test-forms, which include various combinations of graphic elements of different complexity. This method has got the most practical application due to its simplicity and availability. However, it has, at least, two obvious drawbacks. Firstly, it has an utilitarian empiric character, it is limited by the narrow scopes of the research. Secondly, it does not allow using the obtained information for forecasting and automation of the exposure process.

The calculation method for determining the exposure value of photo-polymerizing materials necessary for forming of latent relief image on a photo-plate has been sug­gested.

Unlike the existing research methods for determining the value of necessary time for exposure, this method allows to shorten various spending for the estimation of the exposure value substantially. In addition, the program of the exposure timing has been created depending on the different parameters of photo-plate on the basis of this method.

The most responsible stage of technological process of manufacturing photo-polymer printing plates (PPP), which determines their quality, is the irradiation of photo-polymerizing plates (PPP) during which photo-initiated polymerization is in the layer of photo-polymerizing composition (PPC) and as a result, the formation of latent relief image which then shows up on the stage of washing out of PPP. The duration of the irradiation operation (i.e. exposure value) depends, in particular, on light-sensitivity of PPC, spectral composition and light intensity, quality and complication of photo-plate.

Keywords: photo-polymer printing plate (PPP), relief image, exposure, irradiation, superficial layer.

doi: 10.32403/0554-4866-2019-1-77-63-69