7 Chemicals Used in Ice Packs – Composition and Function

Ice pack is a product developed to treat several health problems such as sprain, strains, bruise and many other minor injuries. This product is also useful to treat fever. Despite having the name ice pack, this product is more than just ices. It contains chemicals for several purposes. For example, ice packs last longer while it can generate cool sensation faster than a real ice can do.

Chemicals in ice packs function to enhance the use of ice packs and expand the benefit of it just like chemicals in joint compound. Cold pack is beneficial for cold therapy and soothes inflammation as well as reduces swelling. Unlike the conventional ice, cold pack is portable and easier to use.

What are chemicals used in ice packs? Here is the list of chemicals used in ice packs:

  1. Ammonium Nitrate

The most common chemical in cold pack is ammonium nitrate. Ammonium nitrate is a compound with ammonium cation and nitrate combination. It is highly soluble in water and usually used as explosive. Coming with white crystal solid form, the chemical is irritable when it comes in contact with human skin. The chemical has high boiling point of 210 Celsius degree of temperature. There is a reaction ammonium nitrate creates that makes it an ingredient in ice pack

Ammonium nitrate functions to cool the pack and produce cold temperature. The placement of ammonium nitrate is in separate bag with the ice pack. Through squeezing, it will produce cooling sensation. The reaction of cooling process is called endothermic reaction. Because of this very reason, ammonium nitrate is one of crucial chemicals used in ice packs.

  1. Urea

Another chemical in ice pack is urea. Even though it is commonly found as agricultural fertilizer, it is also useful in other production of certain products. One of them is for ice pack. The utilization of urea for ice pack is similar to ammonium nitrate. It also creates endothermic reaction. Urea is an organic compound with white solid form and 133 to 135 Celsius degree of melting point. The chemical is also soluble in water.

In order to create endothermic reaction, urea needs water. When urea mixes with water, it will start to cool down the temperature and produces cooling sensation. While ammonium nitrate leakage may cause irritation, urea’s use in ice pack is safer. Modern ice pack uses urea more than ammonium nitrate now.

Also read: Chemicals Used in Artificial Rain for other use of Urea.

  1. Hydroxyethyl Cellulose

Hydrodexyletyl cellulose is a thickening agent and gel made from cellulose. The chemical is used widely in industry either in cleaning agent, drugs and medicine, and cosmetics. It has the melting point at 140 Celsius degree. In ice pack, hydroxylethyl cellulose functions as the thickening agent of the sachet pack. It is the external seal of the ice pack. However, some experts are suspicious whether this chemical is safe or not for ice pack production. Thus, it is advisable not to overuse ice pack with this chemical. To know more if certain chemical may be dangerous, read Harmful Chemicals in the Environment

  1. Sodium Polyacrylate

Sodium polyacrylate is the sodium salt of the chemical compound polyacrylic acid. This chemical is widely utilized in consumer products. Also, this chemical belongs to polymer that is super absorbent in water mass. This makes the chemical a favourable choice for product sealing. In ice pack, sodium polyacrylate function as the gel container just like hydroxyletyl cellulose. Its absorption molecules make it an ideal seal for the ice pack. As a result, the gel ice pack becomes more flexible to use. Hence, sodium polyacrylate is one of the chemicals used in ice pack.

  1. Ammonium Chloride

While ammonium nitrate is common in old version of ice pack, the new modern version of ice pack also uses ammonium chloride. Ammonium chloride is an inorganic compound with formula NH4Cl. the chemical is formed according to the reaction of ammonia and acid. The main use of it usually is for agricultural stabilizer and flavor agents.

In ice pack, ammonium chloride also acts to trigger endothermic reaction. Ammonium chloride does not need great amount of water to produce cold temperature. It is also less dangerous than ammonium nitrate and is featured in the gel pack as well. Therefore, ammonium chloride is one of the crucial chemicals used in ice pack. 

  1. Silica Gel

Silica gel is a common chemical to protect product from fungi and insect attack. It is considered to be the best and most common protector. The composition of silica gel consists of granular, porous, vitreous and silicon dioxide. The chemical is also beneficial to control the humidity of a product in a closed seal. The silica gel comes with many types but the function is all similar.

In ice pack, silica gel is commonly found in gel ice pack where the gel of it contains silica gel. It functions as preservative to make the ice pack lasts longer because it protects the product from humidity effect. However, silica gel is not edible, thus people should be aware of not using it along with food. (Related to Examples of Inorganic Compounds Found at Home).

  1. Diethylene Glycol

Diethylene glycol is organic compound with hygroscopic liquid. It is odorless and has somewhat sweet taste. The chemical was originally considered as promising chemical in industry. In the early production of ice pack, diethylene glycol is among the composition. In ice pack, the chemical acts as freezer that keeps the product to last long. However, after experts conducted research and case study, diethylene glycol is considered poisonous and toxic and shouldn’t be used in any products.

Ice pack is very useful and a good choice to replace ice crush as ice does not last long. People widely used it as it is more practical and easy than having to crush ice. However, as listed already, ice pack can function because of the chemicals it contains. Therefore, people should be aware of its composition in case it has harmful chemical in it.

Also read: Common Chemicals Used at Home