Warmers by
THERMOPAD operate on a chemical reaction with air that is similar to rusting.
The warmer ingredients are: iron, water, cellulose, vermiculite, activated carbon and salt. The heating process takes place in this fashion:
The iron in the pouch, when exposed to oxygen, oxidizes and therefore produces heat. When iron oxidizes it produces iron oxide, more commonly referred to as rust.
The salt acts as a catalyst. The carbon helps disperse the heat. The vermiculite is used as an insulator for the purpose of retaining heat and the cellulose is added as a filler.
All these ingredients are surrounded by a polypropylene bag. Polypropylene allows air to permeate the ingredients while holding in moisture.
