Corona treatment effect of plastic film
Apr 16, 2019
Plastic film is the most widely used in the packaging field, and can be used for food packaging, electrical product packaging, daily necessities packaging, clothing packaging and the like. They have one thing in common, that is, the plastic film should be color-printed, and as a food package, a multi-layer composite or vacuum aluminum plating process is required.
Therefore, the plastic film is required to have a high free energy and a large wet tension to facilitate the firm adhesion of the printing ink, the adhesive or the aluminized layer to the plastic film; in the production process of the plastic film winding and high-speed packaging, The surface of the film is required to have a certain frictional property to prevent the film from sticking or slipping; when used for packaging of electrical appliances, electronic products, etc., the film is required to have certain antistatic properties, etc.
The longest method of surface treatment of plastic film is corona treatment, which is to generate a discharge by applying a high-frequency, high-voltage power source between the metal electrode and the corona treatment roller, thereby ionizing the air and forming a large amount of ozone. At the same time, high-energy electric sparks impact the surface of the film. Under their joint action, the surface of the plastic film is activated and the surface energy is increased.
The wet tension of the polyolefin film can be increased to 38 dynes/cm by corona treatment; the surface wet tension of the polyester film can be made 52-56 dynes/cm or more. The surface tension of the corona-treated plastic film is related to the level of the voltage applied to the electrode, the distance between the electrode and the corona treatment roller, and the like. Of course, the corona treatment should be moderate, not the higher the corona treatment strength, the better.
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