Case study of UV ink printing PE film

Date: Feb 11 2025 From: Star Color

Plastic film is a common packaging material widely used across various industries, with a diverse range of types such as PET, PP, BOPP, PE, each possessing unique characteristics and applications. Today, we will focus on the printing issues related to PE film. It is well-known that the relationship between the surface tension of plastic film and the wettability of UV ink affects the printing quality of the product.

1. Principles of Plastic Film Surface Tension and UV Ink Wettability

Plastic films, especially PE/PP films, typically have a surface energy of 30-34 dynes. This value directly influences whether UV ink can spread evenly and adhere firmly to the film surface. From a physicochemical perspective, the wettability of a liquid on a solid surface follows Young's equation. Simply put, when the surface energy of a solid is higher, it is easier for a liquid to spread on it and form good adhesion. For the UV ink and plastic film system, the surface energy of the film is a critical factor determining the wettability of the ink.

According to industry standards, to achieve good printing results on PE/PP films, the surface energy needs to be increased to above 38 dynes. This is because when the surface energy of the film is lower than the surface tension of the ink, according to the critical value rule, the ink cannot distribute evenly on the film surface, leading to issues such as cratering and ink detachment. Cratering manifests as tiny holes on the printed pattern surface, severely affecting the aesthetic appeal of the product. Ink detachment results in insufficient adhesion between the ink and the film, causing the ink to easily peel off the film surface during subsequent processing or use, greatly reducing printing quality.
Case study of UV ink printing PE film

2. Case Study of a PE Film Brand

A brand producing plastic packaging products used PE film as the printing substrate. Initially, the surface energy of the PE film, which had not undergone corona treatment, was only 32 dynes. After printing with UV ink, the product exhibited severe quality issues. Large areas of the printed pattern showed cratering, causing the details to be blurred. At the same time, ink detachment was also severe, with the ink peeling off in patches when the printed surface was gently wiped. This resulted in an extremely low product qualification rate of only about 30%, increasing production costs and severely affecting the brand's reputation.

To address these issues, the brand introduced corona treatment technology. Corona treatment is a method that uses high-voltage discharge to cause physical and chemical changes on the film surface, thereby increasing its surface energy. After corona treatment, the surface energy of the brand's PE film was successfully increased to above 40 dynes. After printing with UV ink again, the results were transformative. The UV ink adhesion increased by 300%, with clear and sharp printing patterns, vibrant and saturated colors, and nearly complete elimination of cratering and ink detachment. The product qualification rate significantly increased to above 90%, not only meeting customer demands for high-quality printing but also helping the company reduce production costs and improve production efficiency.

3. Role and Advantages of Corona Treatment

The application of corona treatment technology plays an irreplaceable role in increasing the surface energy of plastic films and improving the wettability of UV ink. Firstly, corona treatment can effectively increase the surface energy of the film without altering its overall properties, making it meet the printing requirements of UV ink. Secondly, this technology is simple to operate and cost-effective, suitable for large-scale industrial production. Compared to other surface treatment methods such as chemical treatment and plasma treatment, corona treatment offers advantages such as lower equipment investment, faster processing speeds, and no pollution.

For plastic product printing enterprises, it is crucial to have a deep understanding of the relationship between the surface tension of plastic films and the wettability of UV ink. Only by reasonably utilizing surface treatment technologies, such as corona treatment, can product quality be effectively improved and market competitiveness enhanced.
Case study of UV ink printing PE film

In addition to addressing the relationship between the surface tension of plastic films and the wettability of UV ink, selecting a high-quality UV ink is also key to improving printing quality. Among numerous UV ink products, Zhongzhixing UV ink stands out as a top choice for many enterprises.

Zhongzhixing UV ink demonstrates exceptional performance. Its surface tension is highly compatible with the surface energy of PE/PP films that have undergone corona treatment to reach above 40 dynes, effectively avoiding issues such as cratering and ink detachment. Based on a precise understanding of the critical value rule, the Zhongzhixing UV ink research and development team optimized the formula to enable the ink to spread evenly and adhere firmly on films with suitable surface energy, resulting in clear and sharp printing patterns with lasting vibrant colors.

Choosing Zhongzhixing UV ink is not only selecting a high-quality ink product but also opting for an efficient and environmentally friendly production solution. It helps printing enterprises win the trust of more customers with excellent printing quality in the fiercely competitive market, enhancing their market competitiveness.