What Are Hot/Cold Packs Made Of?
Hot/cold packs are a perfect addition to most first aid kits and they are great for treating a variety of first aid injuries and chronic pains, from bruises and strains to back pains. But how do they change temperature so quickly? And what is the blue gel in reusable packs?
Instant Ice Packs:
Instant hot and cold packs work by carrying out rapid exothermic or endothermic reactions within their plastic bag casing.
Exothermic reaction – a reaction where heat energy is released into the surrounding environment (hot pack)
Endothermic reaction – a reaction where heat energy is taken from the environment to aid in speeding up the reaction process (cold pack)
Typically when using an instant pack the user will burst a small capsule containing water (non-ionic compound) which will then dissolve a chemical salt (ionic compound). Depending on the salt used this results in either a cooling effect from an endothermic reaction or a warming effect from and exothermic reaction. The salt used in cold packs is generally ammonium chloride and hot packs use either magnesium sulfate or calcium chloride. Both reactions are instant and you can feel the effects for up to 40 minutes which can then provide you with effective and targeted pain relief.
Reusable Hot/Cold Packs:
Reusable hot and cold packs are simply a plastic bag which is then filled with refrigerant gel, usually dyed blue in colour. The refrigerant gel is normally a mixture of water soluble starch or cellulose and water, this means that it always stays flexible even after being put in a freezer making it easy to apply. What is also means is that if the pack is damaged then the gel inside is completely safe on the users skin. They are less sciency than instant packs as they don’t involve any fancy chemical reaction, the gel is just a strong insulator that holds its temperature very well. This means that when you place them in the freezer or microwave they stay at the required temperature for a longer duration than instant packs before becoming room temperature.
So now you know all about what they’re made of, check out our wide selection of both Instant and Reusable packs at IcePacks4Less.co.uk. Most of which are by the market leader in hot/cold therapy, Koolpak, so you can be sure you’re getting quality products to ease your pain.
Our best selling instant Ice packs - simply squeeze and shake to activate