The moisture-proof design of plastic blister packaging egg trays requires comprehensive consideration from multiple dimensions, including material selection, structural optimization, process improvement, and adaptation to usage scenarios. Its core lies in blocking moisture penetration paths, reducing the risk of moisture absorption, and improving environmental adaptability.
Material selection is fundamental to moisture-proof performance. Traditional paper egg trays easily absorb moisture and soften due to the hydrophilicity of cellulose fibers, while plastic blister trays achieve hydrophobicity through their polymer structure. Polyethylene (PE) and polypropylene (PP) are commonly used materials; the non-polar groups in their molecular chains allow water contact angles exceeding 90°, effectively preventing moisture penetration. Some products employ blending modification technology, adding nano-silica or fluorides to further reduce surface energy, creating a lotus leaf-like hydrophobic effect, significantly improving the tray's dimensional stability in humid environments.
Structural design must balance the conflict between ventilation and moisture prevention. Egg storage requires air circulation to prevent mold growth, but excessive ventilation can exacerbate moisture intrusion. The vacuum forming process achieves micro-ventilation through precise control of the groove depth and spacing: Hidden guide channels at the bottom of the grooves ensure slow air exchange while preventing direct moisture contact with the egg-shaped tray; the tray edges feature a double-layered folded structure, with the outer layer blocking large-scale moisture vapor and the inner layer guiding condensation to a collection tank via capillary action to prevent localized water accumulation. Modular designs, such as detachable unit trays, allow for flexible switching between single-layer moisture protection and multi-layer stacking via slotted sealing.
Process improvements focus on surface treatment and structural reinforcement. Coating technology is key to improving moisture resistance; water-based polyurethane coatings form a 0.1-0.3mm breathable and waterproof membrane on the tray surface, its microporous structure allowing gas exchange while blocking liquid water; plasma treatment etches the material surface with ionized gas, increasing roughness before spraying with siloxane, forming a composite coating that combines anti-slip and moisture-proof properties. For structural reinforcement, honeycomb-shaped reinforcing ribs are embedded inside the tray during vacuum forming, increasing compressive strength and reducing condensation caused by heat conduction through air gaps.
Usage scenario adaptation requires targeted optimization. For cold chain transportation, plastic blister packaging uses low-temperature modified PP material to prevent cracking of the moisture barrier caused by low-temperature embrittlement. Anti-slip textures and drainage holes are added to the bottom to prevent thawing water accumulation. For humid southern storage environments, the pallet edges are designed as removable waterproof barriers, connected to adjacent pallets via silicone sealing strips to form a continuous moisture barrier. Some high-end products integrate humidity sensing chips, automatically triggering warning lights when ambient humidity exceeds a threshold, prompting adjustments to storage conditions.
The airtight design of plastic blister packaging is the last line of defense in the moisture-proof system. Plastic blister packaging uses a heat-sealing process to achieve a seamless connection between the pallet and the lid, with the heat-sealing temperature controlled between 180-220℃ to ensure weld strength while preventing material degradation. For scenarios requiring repeated opening, a magnetic lid design is used, with built-in neodymium magnets providing uniform adhesion, combined with sealing strips to achieve IPX4 waterproof performance, effectively blocking splashed water and humid air.
Environmental control and pallet moisture-proof performance work synergistically. In the warehousing process, dehumidifiers are used to control relative humidity between 45% and 65%, and 0.5mm high support feet at the bottom of the pallets create an air convection layer to accelerate moisture evaporation. During transportation, EPE (expanded polyethylene) foam padding is used; its closed-cell structure can absorb 90% of moisture. From molecular-level hydrophobic modification to macroscopic-level ventilation and airflow, from static sealing to dynamic environmental response, every aspect of the design optimization aims to build a multi-layered moisture barrier. With the development of IoT technology and new polymer materials, future pallet moisture-proof systems will evolve towards intelligence and self-adaptation, providing more reliable quality assurance for egg storage.
