Generally, the insulation time of the insulated lunch box is three hours, and the good quality may reach five hours. This depends on the quality of the insulated lunch box and the outside temperature. In hot summer, the insulation time of the insulated lunch box will be longer, even more than six hours, but the food is easy to deteriorate in summer, so we should master the insulation time. If in the cold winter, the insulation time of the insulated lunch box will also be shortened. Pay attention when using it. Don't let the food get cold, or you'll be in trouble again.

Extended data:

The insulated lunch box is composed of ordinary lunch boxes, with an insulated shell, the inner and outer layers filled with foam plastic, and the inner layer plated with metal film. Reduce heat loss caused by conduction, radiation and convection. An electric heating device is installed between the lunch box and the shell to supplement the heat loss and keep the food at a certain high temperature.