Curing Equipment for Plastic Surfaces: Testing and Applications

Electrical shock or breakdown

Under the influence of a high-voltage electric field, the strong impact of the electron flow on the plastic film can cause the surface to become fuzzy and rough, thereby increasing the surface area. When the adhesive comes into contact with the surface, it can produce good wetting, allowing the adhesive to penetrate into the grooves created by the roughening, relying on the "anchoring" effect to firmly bond the film—a physical action. Under a high-powered magnifying glass, the treated film's surface appears significantly uneven and rough compared to the untreated film.

The intensity of electrical shock can increase with the rise in voltage and current.

2. Increase the polarity of the film

Under the influence of a high-voltage electric field, oxygen in the air is converted into ozone, which then decomposes into oxygen and new生态 oxygen atoms. These new生态 oxygen atoms act as strong oxidizers, capable of oxidizing α-carbon atoms in polyethylene or polypropylene molecules, forming carbonyl or hydroxyl groups. With this structure, the polarity of the film molecules increases, surface tension improves, and affinity for adhesives enhances, leading to higher bonding strength between composite films. Additionally, the formation of carbonyl groups results in the creation of new α-carbon atoms in the molecular chains, producing reactive hydrogens. These reactive hydrogens can undergo a chemical reaction with the reactive isocyanate groups (-NCO) in polyurethane adhesives, forming strong chemical bonds between the adhered materials and the adhesive, further increasing bonding strength. Infrared spectroscopy analysis reveals the presence of carbonyl or hydroxyl absorption peaks on the spectrum of the treated polyolefin film surface, confirming the occurrence of the aforementioned chemical reactions.