Polyurea is a type of elastomer that is derived from the reaction product of an isocyanate component and a synthetic resin blend component through step-growth polymerization. The isocyanate can be aromatic or aliphatic in nature. It can be monomer, polymer, or any variant reaction of isocyanates, quasi-prepolymer or a prepolymer. The prepolymer, or quasi-prepolymer, can be made of an amine-terminated polymer resin, or a hydroxyl-terminated polymer resin.
The resin blend may be made up of amine-terminated polymer resins, and/or amine-terminated chain extenders. The amine-terminated polymer resins will not have any intentional hydroxyl moieties. Any hydroxyls are the result of incomplete conversion to the amine-terminated polymer resins. The resin blend may also contain additives, or non-primary components. These additives may contain hydroxyls, such as pre-dispersed pigments in a polyol carrier. Normally, the resin blend will not contain a catalyst(s).
Aromatic vs Aliphatic
“Aromatic“ Systems
These are polyureas based on an aromatic diisocyanate (e.g. MDI, TDI,..). Their performance level is excellent, but these are not light-stable. This means the surface changes colour in sun light but does not degrade the physical properties.
“Aliphatic“ Systems
These are polyureas based on an aliphatic diisocyanate (e.g. IPDI, HDI,…). They are light-stable, which means they don’t change colour when exposed to light (sun or artificial). Aliphatic systems are more difficult to process and generally cost twice as much as aromatic polyureas.
| PROPERTIES | AROMATIC POLYUREA | ALIPHATIC POLYUREA |
| Performance | Workhorse | Superior | Application | Base coat | Top coat | Colour Stability | Tends to chalk or darken in colour when exposed to UV | 100% colour stable non yellowing exhibits good outdoor weathering | Finish | Matt | Glossy | Chemical Resistance | Excellent | Excellent | Waterproofing | Excellent | Excellent | Durability | Much better than other coatings | Even more durable | Minimum thickness | 1.5 mm (60 mils) | 0.75 mm (30 mils) |
What is Polyurea?
Two-component elastomeric coating materials for substrate protection from water ingress and corrosion prevention
Derived from the reaction of an Isocyanate component & polyetheramines through one – step polymerization
Wide variety of formulations catering for different requirements for mechanical, physical and chemical properties
Exponential rise in the marketplace in the past 10 years or so throughout the World especially in North America and Asia
Key Components of Polyurea
Polyurea is the result of combining two basic chemical ingredients.
A component:
A side – Consists of Isocyanate (ISO), designated in most instances by the letter “A” and the color red.
- Isocyanate
B component:
B side – The resin blend is second chemical component of the system, designated by the letter “B” and the color blue.
- Polyetheramine
- Amine chain extender
- Pigments
- Flame retardants
- Defoamer
- Other property enhancement additives