The polyurea is a synthetic polymer obtained from the reaction of a diamine with a diisocyanate, polymerization reaction is very similar to polyurethane one, but in case of polyurea, resulting link is a "urea", so it is called polyurea.
By this link we get from generating molecular structure an insensitivity to moisture, thus making the polyurea (if pure) the best waterproof membrane. It is known for its rapid curing time and high strength, making it useful in a variety of industrial and commercial applications, such as construction waterproofing, coatings for truck beds, industrial flooring, and tank linings. Additionally, it can be used as a sealant and insulation material.
Polyurea is a waterproofing material that is often used in industrial and commercial settings to protect surfaces from water damage. It is applied as a liquid coating, which then quickly cures to form a durable, waterproof barrier. This can be used for waterproofing roofs, foundations, decks, and other surfaces. Also used to seal concrete structures, such as swimming pools, water tanks and retaining walls. Polyurea is known for its excellent resistance to water, chemicals, abrasion and impact, which makes it an ideal option for waterproofing surfaces that are exposed to harsh conditions.
We say "pure" because in the market there are numerous polyurea-called "hybrid", which are a mixture between polyurea and polyurethane. These membranes do not have the same mechanical properties as the pure polyurea
(elongation, abrasion resistance, etc ...). The following graph clearly shows the difference.
Pure Polyurea
socyanate + Polyamine
Molecular structure completely insensitive to moisture. Pure polyurea does not react with water making it the best waterproofing material.
Hybrid Polyurea
Isocyanate + Polyol + Polyamine
A polyol participates in the molecular structure of the hybrids, which gives it properties halfway between pure polyurea and polyurethane.
Polyurethane
Isocyanate + Catalyst + Polyol
Polyurethane needs a catalyst in its structure which adds an extra molecular bond. Excellent waterproofing material but with lower mechanical properties than polyureas.
Polyurea types (pure)
Depending on polyurea chemical structure, it could be of two types: aliphatic or aromatic.
The aromatic polyurea is more tenacious and not resists UV exposure, causing some discoloration and loss of shine, which is not recommended for applications "face side". On the contrary, aliphatic polyurea is resistant to UV radiation and it is excellent as a finish coat, because of its raw materials high costs, it makes it a polyurea of higher price range.