Self-heating or cooling packages have been around for years based on various methods primarily directed toward rigid containers, but this U.S. patent filing by inventors in South Korea published in mid-April is for a self-heating/cooling pouch produced in a four-step process. The invention covers 24 exemplary variations and is accompanied by approximately 50 illustrations.
The pouch comprises a contents-containing section and a temperature-controlling section and a “bag” for a liquid reactant (which may be water) that will exothermically or endothermically react with the temperature control agent when the seal between the two latter sections is ruptured manually.
Applicable film substrates for use include polyethylene, polypropylene or polyester. In one embodiment, it is a stand-up pouch, and in another it is a reportable pouch; there is also an allowance for a transparent window in the film.
Options for the heating element include calcium oxide, calcium hydroxide, magnesium chloride, iron and aluminum. Options for the heat absorption agent (for cooling) include ammonium nitrate, sodium acetate and urea. Potential products include boiled rice, stew and soup.
View the patent here.