Protective film why do corona treatment

Plastic PE protective film corona treatment is a kind of electric shock, it makes the surface of substrates has higher adhesion. Its principle is the use of high frequency high voltage in the treated plastic surface corona discharge ( High frequency ac voltage up to 5000 - 15000V／m2) , produced by low temperature plasma, make plastic surface produce free radicals reaction and make the hair cow crosslinked polymer. Surface is rough and increase its wetting have - of polar solvent The plasma by electric shocks and penetrate into the surface of the printed body destroyed its molecular structure, and will be processed on the surface of oxidation and polarization, ion electric erosion surface, so that increase the adhesion ability on the surface of the substrates. Corona treatment of plastic surface produced by the physical and chemical effects are complex and its effect to control mainly through three aspects: (1) specific electrode system, (2) on the guide roll medium, (3) specific electrode power. Due to the different chemical structures have different atomic bonds, so the effect of the corona treatment of plastic and plastic chemical structure. Different plastic different intensity of corona treatment is needed. With the subjects of BOPP film is proved: BOPP film in production will occur after the change of structure state, in a few days, is a variation of the amorphous polymer into a crystalline form, which affects the corona treatment effect. After corona treatment, plastic surface crosslinking structure than its inner crosslinking structure decreases, so the surface functional groups have higher mobility. So, in the store, a corona treatment effect of recession, a lot of plastic additives by internal migration to the surface, also can make the surface, the influencing factors of adhesion, this negative effect can't completely suppressed. Actually relative humidity can also affect the effect of corona treatment, humidity is depolarization agent, but in general due to the influence is not serious, often in the range of test error, is negligible. If use even dizzy electrical and mechanical processing, can need not consider more. Why protective film do corona treatment? Corona treatment in order to change the surface of the protective film is the purpose of energy, make it easy to printing ink, coating materials and adhesive bonding. Protective film after some processing in the manufacturing process and has good adhesion properties. For such as PE protective film plastic material.