The Ink Rub Tester from IST METZ won the award, a testing device used to determine the degree of cure for UV varnishes and inks. It is suitable for all two-dimensional surfaces of coated paper or film. Traditional scratch and solvent test methods can be carried out mechanically with the IRT – the unit also has the advantage that testing is carried out under steady state conditions. Contact pressure of the test probe can be set with weights, while a constant stroke length of 50 mm is executed. The print run is designed in such a way that an even friction surface is provided. These are the conditions that guarantee a high reproducibility of the test results and thus better quality management in comparison to the more traditional testing methods.
Two types of test can be carried out using the IRT: With the solvent test, a magnetic diaphragm dosing pump is used to apply a pre-defined amount of solvent and the number of double strokes required for penetration of the layer is set. Due to the solvent resistance of the components, various types of solvent can be used here (isopropanol, ethanol, ethyl acetate, etc.).
With a simple swap of the test probe, it is also possible to carry out a scratch test under steady state conditions. Different application discs can be selected here, which have an impact of varying intensity on the material being tested.
During both procedures, the resistance of the ink or varnish film to the solvent or scratching is measured. This resistance is then used as a measurement for the degree of cure.