Page 290 - Training 2019

untreated treated

Test Inks

Surface energy, which is often the case with metals. As a general limit, often 38 mN/m are mentioned: If the
surface energy level is below this value, the adhesion will be bad, above this value the adhesion will be good or
sufficient. Anyway, it is always highly advisable to check the surface energy being necessary for good adhesion
for each special application. The ARCOTEST test inks and test pens are a means for determining the surface
energy value easily and exactly. This serves well to either find out about the necessity of a treatment or cleaning
process in a planned production line, or about its quality in an existing line.

Melinex/Polyester test Method

It is imperative that one qualify this under your production conditions

Test method – fold over a corner of Polyester film and draw a line across both surfaces. Avoid contaminated
material (dust, finger prints on surface) as this will affect your reading. Replace the cap on the pen immediately.

To read test result –
1) With the Melinex test pens from DuPont the “treated” side for printing will leave a clear un-removable
mark, while the untreated side will bead (form droplets).

SURFACE TENSION TRAINING MANUAL 15
Updated - 24 June 2019