How Do Insulated Lunch Bags Work?

Yesterday's lunch box is today's lunch bag. Though you might be nostalgic for those old metal boxes, the modern imprinted insulated lunch cooler bag is a cut above the old lunch box in terms of its ability to keep food fresh. And since every kid and lots of working adults need something to carry his or her lunch, many advertisers are cashing in by marketing with imprinted lunch bags.

Experts recommend that perishable food items, like those commonly stored in a common lunch bag (deli meats, cheese, cooked foods, milk, yogurt, etc.), should always be kept at a temperature below 40 degrees Fahrenheit. This is very difficult to do with a plastic or metal lunch box because neither provides very good insulation. Brown paper bags or plastic bags are even worse. Unless you're able to put your lunch into a refrigerator immediately upon arrival at school or work, chances are good that by the time your lunch break rolls around, you food may be warmer than 40 degrees. Unless, that is, you use an insulated lunch bag. This article mainly introduces how do thermal lunch bags work.

Most promotional insulated lunch bags have multiple layers of insulation. They usually have an outer layer, a lining, and an intermediate layer that provides insulation. The most important thing is the middle layer, because without it, the personalized lunch bag would not be better than your ordinary lunch box.

Thermoses and insulated lunch boxes rely on the vacuum formed between the outer layer and the inner layer to prevent energy loss, while insulated bento bags use dense foam cores to keep food and beverages hot and cold. The denser the foam, the better the insulation.

The foam layer prevents heat from penetrating into the outer layer and keeps the surrounding cold or heat from reaching the items in the bag. You may notice that the outside of a cooler lunch bag filled with heated items will not heat up because it prevents heat from radiating to the surroundings. (The outer layer of most lunch bags is usually made of non-woven fabric, vinyl or heavy fabric.)

As an additional protective layer, many insulated lunch bags have an inner layer or lining made of aluminum foil, heavy vinyl, or waterproof and heat-reflective plastic.

It is heat-reflective, which means that the foil-like inner layer of the bag reflects the radiant heat energy of the food back instead of absorbing the food and allowing it to escape the bag. Therefore, compared with ordinary bags, the food inside can maintain its original temperature, flavor and moisture for a longer time.

This means that insulated lunch bags can also prevent food from spoiling like tin foil.

This is why the insulated lunch bag is essential for those who like to pack their own lunch on the go, for kids who eat homemade lunch at school, and for those who prefer to eat hearty home-cooked meals during the trip than Russian roulette. Pay attention to your health when ordering takeaway or fast food.