Polyurea and polyurethane are copolymers associated with an entire industry. They were introduced into the market about 40 years ago in the manufacturing of Spandex and are still in use today.
In 1990, Mark S. used the two-component Polyurea spray to protect the tabletop edges. Since then, it has been an excellent candidate for different applications because of its intriguing chemistry. It can be used as a concrete coating, linings, steel coating, traffic deck systems, and specialty coating.
This article will briefly focus on the unique properties of Polyurea and its chemistry.
Let’s get started,
Unique Properties of Polyurea
Polyurea has many advantages over other coating materials, such as polyurethane and hybrid systems. It can protect wood, steel, and concrete surfaces from corrosion and abrasion. The most notable thing about Polyurea is that it is more durable, has easy to clean surface, ultraviolet stable, and is less expensive than other alternatives, making it a good choice for various applications.
Here we explain a few unique properties associated with Polyurea making it more popular than other coating materials.
- Rapid Dry Time
Polyurea’s two-component system is unique in terms of its dry time. The most significant advantage of the polyurea system is that it can rapidly dry (typically in less than 30 seconds). Rapid dry time makes it an ideal candidate for various applications, including coating and lining over concrete, decorative areas, and metal surfaces. The rapid dryness time allowed the application areas to return to the services quickly.
- Cost-effective environment-friendly synthesis
Polyurea is easily prepared and has low toxicity and flammability. Two-component fast-set polyurea systems do not require any organic solvent. So, it is an environment-friendly system.
The application process requires special equipment to get the material into the form. The components are mixed in the spray gun and applied on the required surface.
- Water resistance and temperature sensitivity
Water resistance is one of the most important properties of these materials. Polyurea does not absorb water so it can use in areas with high humidity. While the main problem with water resistance in polyurethane/polyurea hybrids and polyurethane systems is that they may foam when exposed to moisture. Moisture can result in porosity, lower density, and poor performance.
While polyurea systems are resistant to moisture, this does not mean they can be applied to wet surfaces. Although the Polyurea will react in the presence of water, the applied system will not bond to the substrate in that area.
It has good adhesion and heat resistance and does not require any solvent. These materials are often referred to as thermoset polymers.
Stability Over UV Light
Regarding overall performance, aromatic polyurea systems have good resistance to ultraviolet light. Even when UV Stabilizers / Antioxidants are used, they will discolor and fade over time when used in light colors for exterior exposure environments.
Aliphatic Polyurea is UV light stable and less susceptible to oxidation and degradation than aromatic. So, they are preferably used where there is direct exposure to light.
Some color stability improvement may be observed by modifying aromatic-based systems with aliphatic isocyanates or chain extenders. These, however, contain aromatic species in the polymer backbone and are not color stable.
Chemistry of Polyurea/ Definition of Polyurea
It is a synthetic elastomer. This elastomer is formed by the reaction of Poly isocyanates with a polyamine (resin blend component), as shown below:
The reaction of Poly isocyanates with poly mine results in urea linkages (-NH-CO-NH-).
In similar coating applications, these resin systems frequently compete with polyurethanes. Just like urethanes, polyurea exhibit superior chemical resistance, durability, and flexibility compared to polyurethane.
Difference Between the Epoxy and Polyurea
The main difference between epoxy and polyurea technology is that different resin systems are used. The amine-terminated resins (- NH2) are used in Polyurea, while hydroxy (-OH) terminated resins are used in polyurethanes.
Aliphatic Polyurea Vs. Aromatic Polyurea
Generally, two types of isocyanates are used in the synthesis of Polyurea.
The aliphatic isocyanates drive aliphatic Polyurea.
Aromatic isocyanates synthesize aromatic Polyurea with another component, usually a polyamine.
Hybrid Polyurea
Hybrid Polyurea combines isocyanate polyol and polyamine with the combined properties of polyurethane and Polyurea. Their properties are changed as compared to pure polyurea coatings. It is a little bit less expensive than pure Polyurea.
Comparison of different properties of Polyurea vs. Hybrid Polyurea vs. Polyurethane
Final Words
Polyurea coating technology is gaining popularity because of its superior characteristics compared to polyurethanes and hybrid Polyurea. The advancement of polyurea spray elastomer technology now provides a highly cost-effective and time-effective solution to a wide range of coating problems.
