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Why PP corrugated sheet need corona treatment?

Why PP corrugated sheet need corona treatment?

Update Time:2021-03-16
What is corona treatment?
Corona treatment is an electric shock treatment that gives the surface of the substrate a stronger adhesion.

corona treated PP corrugated sheet


Under what circumstances should the lightweight plastic sheet be treated with corona?
Polypropylene is an inert material, the adsorption effect of ink is not good.
For printing on Polypropylene meterials, such as PP corrugated sheet / coroplast sheet / correx sheet / corflute sheet, PP honeycomb panels, pp film, if you want the ink to absorb firmly and not easily fall off, corona treatment will be very helpful.


How does corona treatment help the printing effect of the lightweight plastic sheet?
Its principle is to use high frequency high voltage to corona discharge on its surface, to produce out low temperature plasma. The plasma  penetrate into the surface of the printed body by electric shocks to destroy its molecular structure, and further polarity and oxidate the board surface, so as to increase the adhesion ability of the board.
corona treatment on pp corrugated sheet


How to judge whether the corona treatment is qualified?
Dyne test pens (≥38 mN/m) can be used as a quick test tool for surface energy after corona treatment, but are not suitable for tests for printed or coated surfaces. If the test pen draws a continuous line on the corona treated surface, we can say the surface energy of the material is not less than 38 mN/m. If the line is intermittent, the surface energy of the material is less than 38mN/m, indicating it is insufficient or even untreated, and thus does not meet the printing requirements.
Dyne test pens for coroplast sheets


What thickness of lightweight plastic sheet can be corona treated?
The thickness of the sheets is usually 2-6mm.
Generally speaking, the power required for corona treatment of thin sheets (2-6 mm) is small, but the power required for corona treatment of thick sheets (8-10 mm) is double more. 
If the power of the corona treatment machine is can be adjustable, then the machine can operate the corona treatment on either thick pp sheet or thin ones.


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