Surface Tension Dyne Solutions and Pens
Wetting tension solution – determining a substrate’s surface energy
3DT has been a pioneer in the surface treatment industry for more than 28 years. Consequently, we want to provide our customers with some of the simple, yet valuable tools for determining the surface tension and adhesion properties of the substrates with which they work. These are dyne pens and solution.
Dyne pens and dyne solution are used to determine the surface energy of a polyolefin substrate (e.g., polypropylene, polyethylene, etc.) after surface treatment. The surface energy is measured in dynes/cm and is one of industries accepted methods to determine the level of surface treatment the substrate has acquired. This is often refered to as “wettability” (hydrophilic) or “non-wettability” (hydrophobic) properties.
Typical in standard or atmospheric corona treatment, higher dyne levels (higher wettability) have related to higher or increased adhesion levels of water based inks, coatings and laminates. Ultimately the level required for your specific production needs is dependent upon many factors.
Untreated PE and PP have a surface tension of about 30 dynes/cm. After treatment for printing with solvent-based ink, PE and PP should have a value of approximately 38-40 dynes/cm. For printing with water-based ink, the surface should have a value of approximately 42-44 dynes/cm.
Polymer plastics with a surface tension of less than 37 dynes/cm have bonding difficulties. When performing the “Tape Test”, negative results are proof of these bonding problems. For many coating and adhesion applications a surface tension of between 48 to 56 dynes/cm is often required.
For dyne solution, the value of treatment is tested by brushing the solution onto the desired surface and observing whether the solution beads up, pulls in or adheres to the substrate at 2 seconds.
If the dyne solution resists bonding to the substrate it does not possess the surface energy of the specific dynes/cm solution or pen, indicating the level of surface treatment may not be adequate to meet your specific production needs. The solutions are graduated from 34 dynes/cm to 70 dynes/cm. The level of accuracy is plus or minus 1 dynes/cm.
Dyne pens are available in 38 dynes/cm and are a quick, convenient method for determining if a substrate has been surface treated. Both dyne test solution and dyne test pens are available from 3DT. See the tabs to the left for more information.