Thinners and Retarders
Adding a thinner to the ink influences viscosity, flow properties, mesh opening,
drying speed, block resistance, solvent power of the binder and dissolving power,
and also - to a large degree - adhesion to the substrate. As the thinners are already
included in the ink formulation their compatibility is thus guaranteed. It is not
possible to cover all ink types with the two ‘universal thinners’ (UKV1 and UKV2).
For specific reasons we have 13 different thinners available. Technical data sheet,
label of ink can, and range chart show the correct thinners per ink type.
If the ink is applied by means of the spray method (spray gun), very fast evaporating
spray thinners are available. Fast drying of the ink at the surface is critical,
to ensure an even colour deposit.
Retarders are also solvents, having a significantly higher evaporation value. However,
whilst producing an improved mesh opening retarders cause slower drying of the ink
and at the same time and reduced block resistance. Retarders are normally added
together with the thinner for printing fine details and halftones, or where slow
printing speeds are used. Retarders also have an influence on ink viscosity (analogous
to thinners) and are chosen for ink compatibility and adhesion to the substrate,
in combination with thinners.