There are many methods used for increasing the polarity and surface energy of plastics. Treatments that involve high temperature, wet chemicals, etc. are not environment friendly. Methods treating the plastic surface to a high voltage corona and plasma surface activation is friendlier towards the environment than wet chemicals and high flames.
1. Washing and cleaning
2. Mechanical abrasion
3. Chemical etching
4. Solvent treatment
6. Flame treatment or heat treatment
7. Corona discharge
8. Plasma treatment
Washing and cleaning:
It is required to remove any mold release, dust or debris on the product surface. Simple detergent or soap wash is employed.
Abrasive belts or grit roughens the surface to improve adhesion and to give it “Tooth”.
Strong oxidizing agents etch the plastic surface to improve adhesion.
Solvent treatment (hot or cold):
Solvents soften the substrate without causing surface deformation, crazing or cracking.
Prime coat or the base coatings are formulated to adhere to the plastic substrate and to provide a good bond for the top coat.
Flame treatment or heat treatment:
It provides and oxidized surface without using any liquid agents.