How is corona used in relation to plastics decorating?Ĭorona treatment often is used inline of web-based printing machines, such as for treating label materials. MultiDyne’s discharge treats ampules before printing.

Oxidation of the surface increases the surface tension or surface energy, allowing for better wetting by liquids and promoting adhesion. The resulting free radicals rapidly react with the oxidation of products in the corona discharge or with adjoining free radicals on the same or different chain, resulting in a cross-link. The result is a cloud of ionized air – or corona discharge – which then is used for the surface treatment of plastics and other materials.Ĭonsequently, a substance placed under the corona discharge is impacted by the electrons with energy two to three times that necessary to break the molecular bonds on the surface. Let’s take a look at each of these methods of surface treatment, their applications and benefits: What is corona treatment?Ĭorona treatment makes use of a generator and high voltage transformer to create a high voltage/high frequency corona discharge applied through an electrode with small airgap onto the surface to be treated. As a result, the usefulness of polymers greatly increases for decorating and bonding applications. Fortunately, corona and plasma surface treatment modify the surface of polymer substrates and raise their surface energy for printing, coating, painting and adhesive applications. However, polymers typically have insufficient surface energy and poor wettability for most printing and bonding applications. Polypropylene and polyethylene are prime examples. Polymers have many useful properties, making them the material of choice. By Gary Kohlnhofer, sales engineer, 3DT LLC Note how the ink bonds to the surface where treated but beads up where the bottle was not treated. This plastic bottle has been plasma-treated in the center only.

Hdpe surface energy