Topic: Surface determination using the test ink method. Surface tension measurement. Test ink method.
Plasmatreat test inks:
Measuring surface tension
A simple method to measure the surface tension of various materials, such as plastic, glass, and recycled or composite materials, is the determination using test inks. Plasmatreat test inks are an excellent tool for surface determination, quality assurance during ongoing production, and determination of accurate parameters for plasma treatment.
All Plasmatreat test inks are manufactured according to DIN Draft 53364 or ISO 8296.
All Plasmatreat test inks are manufactured according to DIN Draft 53364 or ISO 8296.
The simple application of Plasmatreat test inks
The test ink is applied quickly to the surface using the integrated brush of the bottle. Start with an ink with a high surface tension (such as 72 mN/m) directly after the pretreatment. If the brush stroke edges are stable for two seconds, the surface is easily wettable. Then, the surface tension of the substrate is at least equal to the value of the test ink. If the brush strokes of the test ink contract, the next lower test ink should be used. This way, you are gradually approaching the surface tension value of your material. The surface tension of the material is equal to the value of the test ink last used that showed good wetting for at least 2 seconds.
Good surface wetting 
Poor surface wetting The following test inks are available:
1. Ethanol test inks (C Series)
Suitable for all common surfaces. Non-toxic, non-harmful.
Available from 28 to 72 mN/m (in increments of 2 mN/m)
2. Formamide test inks (A Series)
Especially suited for warmer surfaces, but not for PVC. Longer reading time. Toxic. Teratogenic.
Available from 30 to 72 mN/m (in increments of 2 mN/m)
3. Methanol test inks (B Series)
Suitable for all common surfaces. Toxic.
Available from 28 to 72 mN/m (in increments of 2 mN/m)
Suitable for all common surfaces. Non-toxic, non-harmful.
Available from 28 to 72 mN/m (in increments of 2 mN/m)
2. Formamide test inks (A Series)
Especially suited for warmer surfaces, but not for PVC. Longer reading time. Toxic. Teratogenic.
Available from 30 to 72 mN/m (in increments of 2 mN/m)
3. Methanol test inks (B Series)
Suitable for all common surfaces. Toxic.
Available from 28 to 72 mN/m (in increments of 2 mN/m)
Note:
The maximum measurement error is 2 mN/m. For test series with multiple measurements, the error tolerances are reduced accordingly. As with any measurement process, the determination of surface tension using test inks also requires a critical approach to the measurement results. The measurement values obtained with the test ink method for measuring surface tension are relative values and have limited comparability with other methods. The calculated surface tension can only be a measure of the current state of the substrate because, according to experience, surface tension decreases with storage time.
