Dyne Pens & How to Measure Surface Tension

Dyne test ink is used in the packaging industry to control that a plastic substrate has sufficient surface tension for printing, coating and laminating processes.

To avoid having to scrap large quantities of substrate with a poor print due to insufficient bonding it is always advisable to check Corona treated material before printing. Using a felt tipped Dyne test pen is an easy and inexpensive way to check if a substrate is ready for printing.

We carry non-poison PINK pens and inks and BLUE formamide mixture pens of defined surface tensions for wettability and metal cleanliness testing. They identify the necessity of corona, plasma or gas flame treatments or cleaning processes in planned production lines, or its testing of quality in existing lines. 

PINK (17-08xx and 18-08xx) Pens and Inks

  • The pens/inks from 30 to 44 dyne/cm are brighter (the observation time here is 4 seconds)
  • The pens/inks of 28, 29, and 45 to 60 dyne/cm are darker in color (the observation time here is 2 seconds)

This testing method involves determining a dyne/cm level that does not change for a period of 2 seconds. Using a middle value of 38 dynes/cm the testing ink is spread with the test pen felt tip in a linear fashion onto the surface to be tested. If this dyne/cm level does not change for a period of 2 seconds, then it has either the same or higher value.

BLUE (17-07xx and 17-05xx) Pens and Inks

To make possible the printing and adherence of polymer plastics it is inherent that the surface be treated, so that the surface tension rises to a defined point.

Untreated PE and PP have a surface tension of about 30 dynes/cm. Well treated PE and PP should have a value of about 38-41 dynes/cm for printing.

Polymer plastics with a surface tension of less than 37 dynes/cm have binding difficulties. This is recognized in that the tape pull-off test has a negative result.

The value of treatment is tested by simply spreading the testing ink with the felt tip pen onto the surface. This testing method involves determining a dyne/cm level that does not change for a period of 2 seconds. Using Quicktest pen 38®S, spread the ink with the felt tip in a linear fashion onto the surface to be tested. If this dyne/cm level does not change for a period of 2seconds, then it has either the same or higher value.

This test pen is designed for personnel in routine testing purposes. It can give one a good insight of whether the material is being treated enough or not.

The testing inks evaporate quickly when the test pens are not kept closed. Therefore, immediate closure of the pens must take place after use. (The cap will “click” when properly closed.)

The surface tension is a definite criterion for the adhesion of printing ink onto PE and PP. Other factors exist such as exudation of lubricants that influence the adhesion of inks quite negatively, that in turn, do not necessarily register on surface tension testing. Consequently, even though good surface tension results were found, the printing ink adhesion can result negatively.