Corona and Plasma Treatment Processes
Corona and plasma treatment are the most effective methods for improving adhesion on materials resistant to media. These methods of electrical surface treatment are gentle yet powerful and improve the bond strength between substrates and paint, ink, adhesive and coatings.
Many materials have insufficient surface energy for printing and bonding applications. Polypropylene and polyethylene are prime examples. These materials have many useful properties, which make them materials of choice, however, their poor wettability creates severe limitations.
Bond strength between media and substrates relies on one specific property: surface energy or surface tension. Surface tension is measured in dyne/cm (mili N/m) and is the deciding factor on how well a liquid adheres to a surface. For a proper bond to exist between a liquid and a surface, the substrate’s surface tension must exceed the liquid’s surface tension energy by 2-10 dyne/cm. The higher the surface tension of the substrate in relation to the liquid, the better its ‘wettability’. For more information regarding dyne levels and specific substrates please see the chart Necessary Dyne Levels.
3DT has a broad line of systems to overcome the bonding difficulties of plastics, rubber, glass, metal and more. View an introduction to our product line designed for many common surface treatment applications here. All systems can be customized for your needs.
Corona and plasma surface treatment are powerful methods for raising surface tension on materials that traditionally have poor adhesion to inks and adhesives. By understanding the science behind surface treatment, even challenging bonding problems can be successfully solved.
How Surface Energy is Measured
To measure the surface energy of a substrate before treatment or the effectiveness of corona surface treatment, a tensiometer is often used to determine the contact angle of a solution (typically water) on a substrate. Another quick, inexpensive tool are our dyne pens and 3DT’s Dyne Solution Test Kit, which can assess dyne levels and surface wettability, as shown in the Petri dish image on the left. Learn much more about dyne testing on the Dyne Test Solution tab to the left.
Also used to measure the effectiveness of surface treatment is the recently developed automated surface treatment analyzer. This product ensures quick, accurate quality control by calculating dyne levels at the push of a button, without the risk of human error. The automated analyzer is an excellent tool for reliable, accurate surface treatment validation.
Read more about the corona process, plasma process and necessary dyne levels:
Are you wondering, “Do I need Corona or Plasma?” Give us a call or email us to discuss your application. Read our Blog article Corona vs Plasma here.
Check out this informative article about surface treatment methods and benefits.
Surface treatment: Technology spreading to meet quality demands
By Rob Neilley
Does it sound contradictory that suppliers of surface treatment technology say a technology is spreading steadily into new markets and applications, yet many manufacturing engineers don’t think of it at all? Suppliers say that’s the case. Though it can be an advantage when nothing sticks to a plastic product, it’s a big problem when something should.
Surface treatment, broadly defined, is the modification of a surface to achieve good adhesion between it and something applied or bonded to it. It is useful for plastics because they generally have inherently low surface energy. Adhesives, coatings, ink, labels and paint can’t find enough to hang onto. Treatment increases the surface’s energy and wettability, enabling it to form a strong bond with what is being applied.
See the full article here: Surface Treatment Technology – Plastics Machinery Magazine
