White cardboard boxes, a widely used basic material in the packaging industry, rely heavily on surface treatment processes to enhance their scratch and abrasion resistance. Optimizing coating technology, material composites, and process innovations can significantly improve the durability of cardboard boxes, meeting the needs of transportation, display, and long-term storage.
The choice of coating material is the core of surface treatment. Traditional white cardboard boxes often use water-based or oil-based coatings, but these materials have low hardness and are easily scratched by friction. In modern processes, UV-cured coatings have become the mainstream choice due to their high hardness and fast-drying properties. They cure rapidly under ultraviolet light, forming a dense cross-linked structure with a surface hardness of 2H or higher, effectively resisting scratches from sharp objects. Meanwhile, some high-end products incorporate nano-ceramic coatings, using inorganic particles such as silica to fill the coating pores, further improving abrasion resistance and fingerprint resistance, keeping the cardboard box surface smooth even during repeated handling.
Composite reinforcement technology enhances overall performance through a multi-layered structure. Laminating a thin polyester film (PET) or biaxially oriented polypropylene film (BOPP) onto the surface of the white cardboard box significantly enhances scratch resistance. These films possess high transparency and flexibility, protecting the cardboard surface from direct friction while also allowing for a tight bond with the cardboard through a hot-pressing process, avoiding the risk of delamination. Furthermore, some processes employ a "paper-film-paper" sandwich structure, laminating different functional paper layers on both sides of the film, balancing cushioning and aesthetics, making them suitable for packaging precision instruments or fragile items.
Surface texture design disperses friction through physical structure. Traditional smooth surfaces are prone to scratches due to concentrated stress, while embossing, frosting, or matte treatments create micro-uneven structures on the cardboard surface. This design not only increases the coefficient of friction, preventing slippage during handling, but also distributes localized scratching force over a larger area, reducing surface damage. For example, matte treatments reduce surface gloss through chemical etching or mechanical polishing, while simultaneously creating a uniform micro-roughness surface, making scratches less noticeable and improving the visual durability of the packaging.
The introduction of functional additives can specifically improve performance. Adding silica or silicon carbide microparticles to the coating can form a hard protective layer similar to "armor." These microparticles, with a particle size controlled between 1-5 micrometers, do not affect coating transparency and can disperse scratch energy through differences in hardness. Furthermore, some processes employ self-healing coating technology, embedding microencapsulated repair agents within the coating. When minor scratches occur on the surface, the capsules rupture, releasing the repair agent, which fills the scratch through a chemical reaction, restoring surface smoothness and extending the lifespan of the cardboard box.
Optimizing process parameters is crucial for coating performance. During coating, the coating thickness must be precisely controlled within the range of 8-15 micrometers. Too thin a coating will result in insufficient protection, while too thick a coating is prone to cracking or increased costs. Simultaneously, the curing temperature and time must be strictly matched to the coating characteristics; for example, UV curing requires irradiation under 300-400 mJ/cm² UV light intensity for 0.5-2 seconds to ensure complete cross-linking of the coating. In addition, the uniformity of the spraying process directly affects abrasion resistance; using electrostatic spraying technology can improve coating adhesion by 30% and reduce localized weak points.
Environmental adaptability testing verifies the reliability of the surface treatment. White cardboard boxes undergo friction tests simulating transportation scenarios. For example, a 5N pressure is applied to the cardboard surface, and it is rubbed back and forth 1000 times at a speed of 50mm/s, observing the depth of surface scratches and coating peeling. Simultaneously, temperature and humidity cycling tests are conducted, alternating storage in environments ranging from -20℃ to 60℃ and humidity from 30% to 90% to verify the stability of the coating under extreme conditions. These tests help select the optimal surface treatment solution that combines scratch resistance and weather resistance.
The surface treatment of white cardboard boxes achieves significant improvements in scratch resistance and abrasion resistance through innovative coating materials, composite structure design, and process optimization. From high-hardness UV coatings to self-healing microcapsule technology, from physical texture design to the application of functional additives, the integration of multiple technologies allows cardboard boxes to maintain environmentally friendly properties while meeting the stringent requirements of modern logistics for packaging durability, providing a more reliable protective barrier for products.
