All About Polyurea Resin: Composition, Properties

10th January 2024

What is polyurea resin?

Polyurea resin is a polymer resin obtained through the addition-condensation reaction of monomers or prepolymers containing isocyanate groups (NCO) and monomers or prepolymers containing amino groups (NH2 or NRH).

Polyurea resin is a class of high-performance materials with mechanical properties ranging from elastic to rigid, and its comprehensive properties, such as wear resistance, slip resistance, and strength, make it one of the best choices among existing polymer materials. Therefore, it has broad prospects for applications in the field of coatings. Spray polyurea elastomer is one of the varieties that were first developed and widely applied in the late 1990s.

Spray polyurea elastomer (SPUA) technology is a new solvent-free and pollution-free construction technology developed in response to environmental requirements over the past decade, following low (zero) pollution coating technologies such as high-solid coatings, waterborne coatings, radiation-cured coatings, powder coatings, etc.

What is the composition of polyurea resin?

The raw materials primarily used for spray polyurea elastomers can be classified into three main categories: amine-terminated polyethers, isocyanates, and chain extenders. In addition, to enhance properties such as viscosity, flame resistance, aging resistance, antistatic properties, appearance, adhesion, etc., additives such as diluents, flame retardants, antioxidants, antistatic agents, pigments, alkyl coupling agents, etc., may also be incorporated. In the field of Spray Polyurea Elastomer (SPUA) technology, the component formed by the reaction of isocyanate with ether polyols to create a quasi-prepolymer is defined as component A; the component containing end-capped ethers, liquid amine chain extenders, and other additives is defined as component B or R.

Due to the presence of both polyurethane and polyurea structures in the coating, polyurea elastomeric coatings exhibit excellent strength and hardness, along with elasticity and impressive impact resistance. As isocyanates readily react with water or moisture in the air to produce amines and carbon dioxide, the presence of moisture in the system or environment during coating application can lead to the release of carbon dioxide gas from the film, significantly affecting the coating's performance. Therefore, strict control of moisture in the system is crucial during the application process.

Properties of polyurea resin

  • Strong adhesion

Adhesion Spray-applied SPUA (Spray Polyurea Elastomer) materials exhibit excellent adhesion to substrates such as steel, aluminum, and concrete. Through formulation adjustments, even fast-curing systems with gel times as short as around 3 seconds still maintain strong adhesion.

  • Wear Resistance

The wear resistance of polyurea elastomers is 10 times that of carbon steel and 3 to 5 times that of epoxy resin. Therefore, SPUA (Spray Polyurea Elastomer) technology is particularly well-suited for industrial flooring subjected to frequent human or vehicular activity. Additionally, SPUA materials, with their excellent elongation properties, offer a longer service life compared to epoxy flooring. Polyurea elastomers can also be employed to address wear and tear, impact resistance, and corrosion protection challenges in various environmental conditions.

  • Impact Resistance

To assess the impact resistance of SPUA (Spray Polyurea Elastomer) materials, a 500mmX1000mmX50mm reinforced concrete slab was struck with a large hammer to create fractures. A 3~4mm coating of "SPUA-102 Waterproof Wear-resistant Material" was then sprayed on its surface, and the slab was placed in an area frequently traversed by vehicles. After nearly a year and thousands of vehicle impacts and compressions, the coating remains intact with only minor scratch marks on the surface. There has been no evidence of cracking, breaking, or damage. This demonstrates the outstanding ability of SPUA materials to resist impact and fatigue damage.

Is polyurea harmful to humans?

SPUA (Spray Polyurea Elastomer) materials include chemical raw materials such as isocyanates and amine-terminated polyethers, which possess a certain level of toxicity. If safety precautions and protective measures are not observed during spray application, adverse symptoms may occur among construction personnel.

The A component used in SPUA is typically a quasi-prepolymer of MDI, LMDI, or PAPI, containing a significant amount of unreacted isocyanate monomers, which can cause damage to the eyes, respiratory system, and skin.

Respiratory System: It has an irritant effect on the respiratory tract, serving as a potential respiratory allergen. Inhaling a certain amount of gas or airborne particles may lead to respiratory infections, lung damage, and symptoms such as dry throat, chest tightness, difficulty breathing, and/or flu-like symptoms.

Skin Contact: Contact may result in rashes, swelling, stinging, and chemical burns, with repeated or prolonged exposure potentially causing skin allergies.

Eye Contact: Exposure to airborne particles, vapors, or liquid may cause irritation to the eyes, and in severe cases, can result in chemical burns to the eyes.