When examining the question of whether corona treatment is necessary for UV ink printing on PE (polyethylene) film, it is crucial to comprehend the unique characteristics of UV ink, PE film, and corona treatment, as well as their interrelationships.
I. Characteristics of UV Ink
UV ink, also known as ultraviolet-curable ink, has gained widespread adoption in the printing industry due to its rapid curing, exceptional wear resistance, chemical resistance, superior color rendition, and environmental friendliness. By utilizing ultraviolet light for curing, UV ink rapidly solidifies into a stable print layer, making it particularly suitable for applications requiring high print quality and fast production rates.
II. Characteristics of PE Film
PE film, a common plastic film material, boasts excellent physical and chemical properties such as low-temperature resistance, water resistance, and chemical resistance. However, PE film's relatively low surface energy can negatively impact ink adhesion and printing outcomes. Consequently, surface treatment is often necessary to enhance the printability of PE film.
III. Necessity of Corona Treatment
Corona treatment is a widely employed surface treatment method for plastic films. It involves the use of high-frequency, high-voltage discharges to generate tiny, dense electrical sparks that impact the film's surface, causing partial molecular chain degradation. This process increases the surface roughness and specific area, while also ionizing airborne oxygen to form ozone, which removes weak interfacial layers like oil contaminants and oxidizes plastic molecules, introducing hydroxyl and carboxyl groups that convert the film's surface into a polar one with higher surface tension.
In the case of UV ink printing on PE film, the low surface energy of PE film can lead to issues such as poor ink adhesion and ink shedding if printing is attempted directly. Therefore, corona treatment is typically required to enhance the adhesion of UV ink on PE film and optimize the printing outcomes.
IV. Impact of Corona Treatment on UV Ink Printing Results
Improved Adhesion: Corona treatment significantly increases the surface tension of PE film, enabling UV ink to better wet and adhere to the film's surface, thereby strengthening the durability of the print.
Enhanced Printability: By roughening and porosifying the PE film's surface, corona treatment facilitates UV ink penetration and curing, further improving the overall quality of printed products.
Reduced Printing Defects: Corona treatment minimizes printing defects such as ink shedding and blurring caused by inadequate ink adhesion, thereby enhancing the yield of printed products.
In conclusion, when printing UV ink on PE film, corona treatment is generally necessary to ensure robust ink adhesion and high-quality printing results. By enhancing the surface tension and printability of PE film, corona treatment provides optimal conditions for UV ink adhesion and curing. Thus, it represents an indispensable step in the production process of UV ink printing on PE film.