As the name suggests, the lunch box is a bag with heat preservation function, which is suitable for the packaging of various food, fresh and other temperature-sensitive products.
The bento box lunch bag is generally composed of three layers, which are an outer layer, an insulating interlayer and an inner layer. The outer layer is made of oxford cloth or nylon cloth, which is strong and wear-resistant; the heat insulation interlayer is made of EPE pearl cotton insulation material, which can keep cold and heat, and this layer determines the thermal insulation performance of the lunch box; the inner layer is made of aluminum foil, which is radiation-proof and easy to clean.
At present, the bento box lunch bag is widely used in domestic and foreign markets, and the short-distance cold and heat preservation of food and fresh food can be solved by the bento box lunch bag device to solve the problem of thermal insulation aging. Compared with insulation devices such as incubators, lunch boxes are light and easy to fold, which can save space and reduce costs in transportation and storage. We can consider from other perspectives to optimize the heat preservation time of the lunch box lunch pack. The following are for reference:
(1) Material innovation
Of course, the most important material of the lunch bag is the insulation layer. The insulation layer of the bento box lunch bag is made of pearl cotton as the thermal insulation medium. Due to the high thermal conductivity of pearl cotton, its thermal insulation efficiency is limited. In foreign countries, polyurethane foam is used as the thermal insulation layer, which greatly improves the thermal insulation time of the lunch box. The nano-level thermal insulation material developed by the Green Cold Chain Packaging Center replaces pearl cotton, and its thermal insulation performance is comparable to that of common incubators.
(2) Structural innovation
Starting from the optimization of the structure of the bento box lunch bag, it is necessary to consider the structural factors that affect the thermal insulation performance of the bento box lunch bag, such as the absence of thermal insulation material at the seams of the adjacent surfaces of the bento box lunch bag body, and no windproof structure at the zipper of the bag mouth. A large amount of air convection heat transfer leads to a decrease in thermal insulation performance.
Therefore, the structural design of the lunch box can be optimized, and the integrated design of the body of the lunch box can be adopted, and the soft characteristics of the thermal insulation layer can be used to reduce the joints and improve the thermal insulation performance. Corresponding tongue windproof structure can be designed around the zipper of the pocket, which is attached by Velcro, so that the zipper has double protection. In addition, when designing the thermal insulation layer structure, a double-layer thermal insulation material filling design can be carried out, a first thermal insulation layer is formed between the outer layer and the inner layer, and a second thermal insulation layer is formed between the inner and outer layers. It is filled with insulation materials such as pearl cotton, environmentally friendly EVA, wool felt and so on.
In a word, the application of lunch bags has been involved in people's daily life. People can use lunch boxes for shopping, outings, picnics, and work trips to solve the problem of heat preservation and preservation of food. In the future, the lunch box industry will definitely pursue more lightweight, convenient, eco-friendly and efficient products.