Hot and cold packaging

The self-heating or self-cooling cans produced by Japanese food manufacturers are mainly used for the packaging of coffee, soup, rice porridge, noodles, sausages, rice wine, and beverages, and have been mass-produced and put on the market. The cans are made of composite plastic or aluminum with food or beverage on the top and heating or cooling devices on the bottom. The heating is achieved by the mixing of water and quicklime to produce heat; the refrigeration is obtained by chemical reaction of water with ammonium nitrate or ammonium chloride.