Why can cross-linked shrink film effectively resist mechanical scratches?

The wide application of cross-linked shrink film in the packaging field is inseparable from its excellent physical properties. The significantly improved stiffness and surface hardness make it have excellent resistance to surface mechanical scratches, providing a reliable protective barrier for the packaged products during transportation and storage. Behind this feature are precise material science principles and innovative processes.

The molecular chains of ordinary shrink film are arranged linearly and the structure is relatively loose. Under the action of external forces, the molecular chains are prone to relative sliding and displacement, resulting in insufficient rigidity and hardness of the material. When subjected to mechanical external forces such as friction and collision, the surface is prone to scratches and damage. The cross-linked shrink film uses a cross-linking process to form chemical bonds between the molecular chains and construct a three-dimensional network structure. This structure greatly restricts the free movement of the molecular chains, enhances the interaction between the molecular chains, and thus significantly improves the overall rigidity and hardness of the material. Take the common polyethylene cross-linked shrink film as an example. Under the action of electron beams or chemical cross-linking agents, the originally independent linear molecular chains are connected to each other through chemical bonds to form a tightly interwoven network, just like building a solid "skeleton" for the material, enabling it to resist greater external forces without deformation and damage.

The increase in stiffness and hardness of the cross-linked shrink film directly gives it excellent resistance to surface mechanical scratches. In actual logistics, transportation and storage environments, product packaging will inevitably produce friction and collision with surrounding objects. For example, during the stacking process, the lower packaging will be squeezed and rubbed by the upper packaging; during the handling process, the packaging may collide with handling tools, shelves, etc. In these cases, the surface of ordinary shrink film is easily scratched, which not only affects the appearance of the product, but also may weaken the protective performance of the packaging, causing damage to the internal product. The cross-linked shrink film can effectively resist the impact of these mechanical external forces with its high stiffness and hardness. Its surface is like a hard protective layer covered with a layer of hard protective layer. When it is rubbed or collided, it can disperse the external force and reduce the local force, thereby reducing the risk of surface scratches. Even during frequent handling and long-term storage, the integrity of the packaging surface can be maintained, so that the packaged products are always in a good state of protection.

This property of resistance to surface mechanical scratches is of great significance for the packaging of various products. For electronic products, the integrity of their appearance directly affects consumers' willingness to buy and the brand image of the product. Cross-linked shrink film can prevent scratches and wear on the packaging surface during the transportation and storage of electronic products, ensuring that the product is presented to consumers with a perfect appearance. For products such as food and medicine that have high requirements for packaging sealing, scratches on the packaging surface may destroy the integrity of the packaging, causing the product to be damp and contaminated, affecting product quality and safety. The good scratch resistance of cross-linked shrink film can effectively avoid this situation, ensure the sealing of the packaging, and extend the shelf life of the product.

From the perspective of production technology, the regulation of stiffness and hardness of cross-linked shrink film can be achieved in many ways. The degree of cross-linking is one of the key factors. A moderate increase in the degree of cross-linking can further strengthen the connection between molecular chains and improve the rigidity and hardness of the material, but too high a degree of cross-linking may cause the material to become brittle and reduce its flexibility and processing performance. Therefore, it is necessary to precisely control the cross-linking process parameters according to different application requirements to achieve the best performance balance. In addition, adding suitable additives, such as reinforcing fillers, anti-scratch additives, etc., can also help improve the stiffness and surface hardness of the cross-linked shrink film. These additives can fill the gaps in the molecular network, enhance the interaction between molecules, and form a protective film on the surface to further improve the scratch resistance of the material.

With the continuous development of the packaging industry, the performance requirements for cross-linked shrink films are also increasing. In the future, R&D personnel will continue to explore more optimized cross-linking processes and formulas to further improve the surface mechanical scratch resistance of cross-linked shrink films, while taking into account other performance indicators to meet the diversified packaging needs of different fields and different products. Under the general trend of pursuing environmental protection, how to develop degradable, green and environmentally friendly cross-linked shrink film materials while ensuring the excellent performance of cross-linked shrink films will also become an important direction of industry research.