{"id":5170,"date":"2026-06-19T11:50:04","date_gmt":"2026-06-19T09:50:04","guid":{"rendered":"https:\/\/www.alsace-techniques-etiquetage.fr\/?p=5170"},"modified":"2026-06-19T11:50:45","modified_gmt":"2026-06-19T09:50:45","slug":"corona-treatment","status":"publish","type":"post","link":"https:\/\/www.alsace-techniques-etiquetage.fr\/en\/converting\/corona-treatment\/","title":{"rendered":"Corona treatment: the invisible key to adhesion on hard-to-bond materials"},"content":{"rendered":"

An adhesive that won’t hold, ink that wipes off, a coating that peels at the first thermal shock: in the vast majority of cases, the problem lies neither with the adhesive nor the ink, but with the surface itself. Specific plastics, technical films and composite substrates are inherently repellent<\/strong> : nothing bonds to them for long. Corona treatment is the most widely used industrial solution to this problem, and it’s a process we master at ATE.<\/p>\n

This article explains what corona treatment is, how it works, which materials and sectors it applies to, and why integrating it upstream of die-cutting or lamination transforms the reliability of a technical part.<\/p>\n

What is corona treatment?<\/h2>\n

Corona treatment is a surface-modification process that raises a material’s surface energy so it becomes receptive to adhesion<\/strong>. In practice, the surface is exposed to a high-voltage electrical discharge : a \u201ccorona discharge,\u201d hence the name, which alters its surface chemistry.<\/p>\n

Many polymer materials \u2014 polypropylene, polyethylene, some PET or fluorinated films \u2014 have a surface energy too low for an adhesive, ink or varnish to grip properly. Their surface is described as \u201cnon-polar\u201d: liquids bead up instead of spreading out. Corona treatment creates polar chemical groups (oxygen-bearing functions) at the surface, enabling genuine bonding.<\/p>\n

The result is measurable: surface energy, expressed in dynes\/cm (mN\/m), typically rises from a value that is too low to a level sufficient to guarantee durable adhesion. It’s a concrete control criterion, verifiable with test inks or a measuring device.<\/p>\n

How it actually works<\/h2>\n

The material runs between a high-voltage electrode and a conductive roller. The potential difference ionizes the surrounding air and generates a cold plasma \u2014 the visible, crackling corona discharge. As it passes, activated oxygen molecules react with the polymer surface.
\nThree effects combine:<\/p>\n