Why PP corrugated sheet need corona treatment?

Corona treatment is an electric shock treatment that gives the surface of the substrate a stronger adhesion.

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.

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.