An important parameter for the characterization of surfaces is their wettability.

Good wettability is an absolute prerequisite for achieving a homogeneous coating in bonding, painting and printing processes. The change in wettability can also be used to derive the purity of a surface and to obtain information on soiling and cleaning quality since impurities mask the surface.

In a laboratory, the wettability can be determined with expensive laboratory equipment using various test liquids, which is however too costly or impracticable for practical operations (cleaning companies).

Here test inks are used for fast measurements. However, the values determined with different test inks can deviate massively from one another on individual surfaces or do not correlate with laboratory values and largely coincide on others.

According to the working hypothesis of the applicants, the reason for this is that the ink sets on the market do not differentiate between strongly disperse or predominantly polar interactions between inks and surfaces.

This is to be taken into account in the development of new test inks planned here. It is planned to develop a test ink set for strongly disperse and a set for predominantly polar surfaces and to select by means of a master ink which of the two ink sets is suitable for the respective surface.

The aim of the project is the waste avoidance at foil printing and varnishing plants and thus cost reduction as well as the development of a procedure for the examination and documentation of cleaning methods for areas in which the surfaces to be cleaned vary strongly and in addition the examination of large test surfaces is necessary.

The research report is available on request from FRT.