Corona and Plasma Treatment Processes
When it is necessary to bond plastic materials to metals or other plastics, to print or coat on a plastic, silicone, rubber, glass or composite surface, successful results depend on adhesion to that surface. Corona and plasma surface treatment modifies surfaces (invisible to the human eye) and improves bonding for numerous applications. Bond strength relies on one specific property: surface energy or 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 substrate 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 solid substrate in relation to the liquid, the better its ‘wettability’. For more information regarding dyne levels and substrates please see the chart under Necessary Dyne Levels.
Many plastic materials have insufficient surface energy for printing or bonding. 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 when it comes to design choices. 3DT has a broad line of systems to overcome all most bonding difficulties. View an introduction to our product line here.
Read more about the different processes and necessary dyne levels:
- The Corona Process
- The Plasma Process
- 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.