Test pens for quick test of film surface energy

The task

“Is the surface energy of this plastic film sufficient for converting purposes?”

Treated and untreated plastic films are indistinguishable to the naked eye. Usage of insufficiently treated films causes delays and waste, which can quickly became a major problem in an industry that demands highest levels in quality, performance and production output. This is especially true in the converting industry, so information needs to be available quickly and simply.
The application and evaluation of a test ink takes only a few seconds.

To perform the test, a line of ink is applied to the film with the pen and the behaviour of the ink observed. If the ink forms a solid line, the film has a surface energy of at least 38 mN/m and can be used for printing and other converting steps. If the ink contracts and does not form a solid line, the film’s surface energy is below 38 mN/m. This indicates that the film is insufficiently treated for most converting processes.

Its ease of use, reliability and competitive price have made our product the no. 1 best selling corona test pen in the world!



SOFTAL quality


Low operating cost


Repeatable in accordance with DIN ISO standard

Test inks by SOFTAL let you measure the surface energy of test inks quickly and repeatably in accordance with DIN ISO 8296

Quick results

Applying and evaluating a test ink is a matter of seconds.

Simple procedure

To perform the test, the behaviour of a line of ink on the PE or PP film in question is observed. If the line remains solid, the film is sufficiently treated for converting processes.

Complete delivery

Test pens, red, are delivered in boxes of 10.

Reliable results

The test ink used in SOFTAL test pens has a surface energy of 38 mN/m.