Designing a lunch box packaging cushioning structure to reduce the risk of food damage during transport requires comprehensive consideration of multiple dimensions, including material properties, structural form, space utilization, and user scenarios. By scientifically allocating cushioning space, optimizing mechanical support paths, and enhancing structural stability, comprehensive protection for food against dynamic loads such as impact and vibration can be achieved.
The selection of cushioning materials is fundamental to structural design. While traditional foam plastics offer excellent cushioning properties, they are difficult to degrade and are not environmentally friendly. Therefore, biodegradable or recyclable materials are preferred. For example, honeycomb paperboard, with its biomimetic honeycomb structure, combines lightweight and high strength. Its hexagonal cells disperse impact forces, making it suitable for use as partitions or sidewall supports in lunch box packaging. Corrugated paperboard, with its corrugated core layer, increases material thickness, improving its compressive and flexural resistance, and is commonly used in the outer packaging frames of lunch box packaging. Foamed corn starch, a bio-based cushioning material, is not only biodegradable but also allows for adjustable foam density to suit the cushioning needs of different foods. For example, fragile pastries require a high-density foam layer, while pressure-resistant rice balls can use a low-density layer. In addition, the surface of the material needs to be moisture-proof to prevent absorption of food moisture, which could reduce its cushioning performance.
Innovative structural forms must be tailored to the food's shape and transportation scenario. For fragile foods (such as fruit slices and small cakes), a "suspended" cushioning design can be employed: a separate groove is created within the lunch box packaging, with a wavy elastic clip along the edge. Once the food is inserted, it is flexibly secured by the clip, creating a "suspended" state, minimizing direct impact with the box. Furthermore, a honeycomb cardboard cushioning layer is placed at the bottom of the groove to further absorb vertical impact. For liquid foods (such as soups and sauces), a double seal and anti-tip structure is required: an inner silicone seal and threaded cap are combined, while an outer layer is filled with foamed corn starch granules around the bottle body, creating a flexible wrap. Even if the lunch box packaging is tilted or inverted, the liquid is secured by the cushioning material, preventing leakage. For combination lunches (such as separate packaging for main dishes, side dishes, and fruit), a modular, layered structure can be designed: each layer is separated by corrugated cardboard partitions. Raised slots on the edges of the partitions mate with grooves on the inner wall of the lunch box packaging, providing stable support. Furthermore, non-slip silicone pads should be applied to the partitions to prevent the food containers from sliding.
Optimizing space utilization requires balancing cushioning effectiveness with packaging costs. The cushioning structure should not excessively occupy the interior space of the lunch box packaging, otherwise it will reduce the food loading capacity or increase the packaging volume. For example, a "local reinforcement" strategy can be adopted: honeycomb cardboard reinforcement strips can be added to the four corners and edges of the lunch box packaging. These areas are most vulnerable to impact during transportation, significantly improving overall drop resistance, while retaining more space in the center for food storage. For lunch box packaging that needs to be stacked, raised support columns can be designed on the inside of the lid, matching the grooves on the bottom, forming a "column-slot" structure. This enhances stacking stability while preventing the upper boxes from directly pressing on the food below.
Adapting to user scenarios is a key design consideration. For takeout delivery, lunch box packaging must withstand greater vibration and frequent handling, so its cushioning structure requires a higher energy absorption capacity. For example, expanded polypropylene (EPP) particles can be placed between the outer box and the inner lunch box packaging. EPP particles have excellent impact resistance and resilience, absorbing multiple impacts without deforming. Furthermore, a "fragile" label can be printed on the outer box to remind delivery personnel to handle with care. For students bringing their own lunches, the cushioning structure must balance portability and durability. For example, a one-piece corrugated lunch box packaging can be used, with the box body and lid connected by folding snaps to reduce the number of parts. A removable plastic divider with a silicone seal around the edge prevents food from transferring odors while also providing impact absorption through the silicone's elastic properties.
The design of the lunch box packaging's cushioning structure should prioritize food protection. Through material innovation, structural optimization, space utilization, and application adaptation, it should achieve a balance of environmental protection, functionality, and cost-effectiveness, ensuring food safety throughout the entire food supply chain, from storage to consumption.
