What is Two-Component Polyurethane Coating? Properties and Testing Methods

Two-component polyurethane coatings are high-performance protective materials widely used in industries such as oil, gas, petrochemical, and construction. Their outstanding resistance to abrasion, corrosion, chemicals, and UV radiation makes them ideal for demanding conditions. These coatings consist of two reactive components—a resin and a hardener—that chemically react upon mixing to form a tough and durable film. Standards such as IPS-M-TP-235 and INSO 5954 define performance and quality assurance criteria for these coatings.

What Are Two-Component Polyurethane Coatings?

Chemical Structure and Composition:

• Component A (Resin): Typically based on polyols or polyamine compounds, serving as the base material.
• Component B (Hardener): Contains isocyanates that react with the resin to form a cross-linked polyurethane network.

Once mixed, the components undergo a curing process at room or elevated temperature, producing a uniform, resilient, and long-lasting film.

Key Advantages of Two-Component Polyurethane Coatings

1. Chemical Resistance: Exceptional protection against acids, bases, oils, and solvents.
2. UV and Weather Resistance: Maintains color and integrity under prolonged sun exposure.
3. Strong Adhesion: Adheres well to metal, concrete, and wooden surfaces.
4. Flexibility: Absorbs mechanical and thermal stress without cracking.
5. Water Resistance: Excellent performance in humid and marine environments.

IPS-M-TP-235 Requirements (Issued by National Iranian Oil Company)

This standard outlines the technical specifications for industrial-grade polyurethane paints. Key parameters include:

• Viscosity and Density: Must remain within acceptable ranges to ensure smooth application and proper film formation.
• Drying Times: Initial and final drying durations must align with the standard.
• Adhesion Testing: Verified using ASTM D4541 or equivalent methods to confirm adequate bonding.
• Corrosion Resistance: Evaluated through salt spray and fog exposure tests.
• UV Color Stability: The paint must resist yellowing and color degradation under UV light.

INSO 5954 Requirements (Iranian National Standard)

This standard details the visual and performance characteristics of two-component polyurethane paints:

• Appearance: The dried film should be smooth, even, and free from defects like bubbles and cracks.
• Film Thickness: Must comply with defined dry film thickness requirements.
• Hardness: Measured using tests such as the pencil hardness method.
• Flexibility: Evaluated through bending tests to detect cracking.
• Thermal and Environmental Resistance: Coat must tolerate heat cycles and harsh conditions.
• Durability: Proven long-term reliability in industrial and coastal environments.

Standardized Tests for Quality Evaluation

To ensure consistent quality, the following tests are conducted:

• Adhesion Test: Using pull-off or cross-cut methods to verify surface bonding.
• Impact Resistance Test: Measures resistance to mechanical shock.
• Salt Spray Test: Simulates corrosive marine or industrial environments.
• UV Exposure Test: Assesses performance under ultraviolet radiation.
• Hardness Test: Determines surface strength using standardized tools.
• Flexibility Test: Checks crack resistance during bending.

Applications of Two-Component Polyurethane Coatings

Due to their outstanding properties, these coating are widely used in:

• Oil & Gas Industry: Coating pipelines, tanks, and offshore installations.
• Construction Sector: Applied to steel structures and concrete surfaces for protection and aesthetics.
• Automotive Industry: Used for external vehicle surfaces to resist weather and impact.
• Marine Applications: Ideal for ships and coastal infrastructure exposed to moisture and salt.

Featured Product: ABACOAT PUR-40 by Abadgaran

ABACOAT PUR-40 is a two-component polyurethane coat formulated with acrylic polyol resin and isocyanate hardener. It offers high mechanical strength, excellent adhesion, and long-term resistance to UV and harsh environments. Often used as a topcoat over epoxy primers and intermediates, it delivers a durable, flexible, and visually appealing finish.

Conclusion

Two-component polyurethane paints are a reliable choice for industrial and commercial coatings, offering exceptional durability, flexibility, and resistance to environmental stress. Standards IPS-M-TP-235 and INSO 5954 are essential for ensuring consistent performance and safety. By following standardized testing and application methods, the lifespan and effectiveness of these products are significantly enhanced across a wide range of industries.

References:

1. IPS-M-TP-235: Technical Specifications for Industrial Paints, National Iranian Oil Company
2. INSO 5954: National Standard for Two-Component Polyurethane Paints, ISIRI
3. ASTM D4541: Pull-Off Strength of Coatings Using Portable Adhesion Testers