It won't go bad as long as it's not overnight. Just put it in an incubator when it is ready in the morning. Many parents bring meals to their children in this way.

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.

It is characterized by long heat preservation time and can be reheated when you want to eat; Fashionable appearance, light and portable; Compared with the insulated lunch boxes on the market, the price is relatively affordable, and the products are green, environmentally friendly, energy-saving and beautiful.

Generally, it is a food container made of double-layer plastic or stainless steel plus vacuum layer or heat insulation layer. The top is covered and sealed tightly. The vacuum layer or heat insulation layer can delay the heat dissipation of the food inside, thus achieving the purpose of heat preservation. The insulated lunch box is developed from the thermos bottle, and the insulation principle is the same as that of the thermos bottle.

There are three ways to spread heat: radiation, convection and transmission. The silver liner in the heat preservation barrel can reflect heat radiation, and the vacuum layer or heat insulation layer of the cup can block heat transfer.

Modern thermal insulation lunch box adopts high-tech vacuum technology to vacuum the interior of double-layer high-quality 304 stainless steel, which can effectively block the heat source and achieve the effect of thermal insulation. The design is more humanized. Usually designed as three or four layers (as shown in the figure). Putting a high-temperature lunch box and soup box under the insulation barrel, then covering the insulation board in the middle and putting the food box on it will not only bring you the best insulation effect, but also keep your food and beverage warm longer and fresher.

References:

Baidu encyclopedia-insulation lunch box