Understanding Aliphatic vs. Aromatic Coatings: What’s the Difference and Which Should You Choose?

When it comes to protective coatings, selecting the right formulation can significantly impact both performance and cost-effectiveness. At UMI Coatings, we specialize in delivering advanced coatings systems designed to meet the demands of various industries—from infrastructure and manufacturing to secondary containment and marine environments. One of the most common questions we encounter is: what’s the difference between aliphatic and aromatic coatings?

Below we’ll break down the chemistry, performance characteristics, and application use cases for both coating types. Our goal is to help original manufactures, contractors, engineers, and specifiers make more informed decisions about which coating is best suited for a given job—not to say one is always better than the other, but to highlight how each plays a critical role depending on the environment and performance requirements. 

The Chemistry Behind the Names

At their core, the terms aliphatic and aromatic refer to the molecular structure of the isocyanates used in polyurethane and polyurea coatings. 

• Aromatic coatings are based on aromatic isocyanates, such as methylene diphenyl diisocyanate (MDI) or toluene diisocyanate (TDI). These chemical structures include a benzene ring, which makes them reactive and cost-effective to produce. 

• Aliphatic coatings, on the other hand, are derived from aliphatic isocyanates like hexamethylene diisocyanate (HDI). These structures lack the benzene ring and tend to be more stable under UV exposure—hence their popularity in outdoor or color-sensitive applications. 

  
  

Understanding the molecular difference is key because it largely determines the coating’s behavior when exposed to light, chemicals, and environmental wear.

UV Resistance and Color Stability 

One of the biggest differentiators between aromatic and aliphatic coatings is their ability to resist UV degradation. 

• Aromatic Coatings: While highly durable and tough, aromatic systems tend to yellow or chalk when exposed to UV rays over time. This doesn’t typically affect their mechanical performance, but it can be a drawback in applications where appearance matters. 

• Aliphatic Coatings: These coatings offer excellent UV resistance and retain their color and gloss over time, making them ideal for surfaces exposed to sunlight or where aesthetics are important—like exterior decks, truck beds, fire trucks, or boats. Additionally, aliphatic coatings are used on assets where matching the color of the underlying material is important—emergency vehicles, for instance.  

Cost Considerations 

• Aromatic coatings are significantly more cost-effective than their aliphatic counterparts. This makes them a go-to solution for large-scale industrial applications where aesthetics aren’t a concern and performance under UV isn’t a primary factor—such as in below-grade waterproofing, tank linings, or wastewater facilities. 

• Aliphatic coatings, due to their complex synthesis and higher UV stability, generally come at a premium. Their use is often justified in projects where long-term appearance, outdoor exposure, or color retention is a must. 

  
  

Performance and Application Use Cases 

Both aliphatic and aromatic coatings offer outstanding physical properties such as abrasion resistance, chemical resistance, and flexibility. However, they shine in different environments: 

Best Use Cases for Aromatic Coatings: 

• Concrete containment tanks 

• Secondary containment areas 

• Wastewater and stormwater infrastructure 

• Foundation walls 

• Parking garages 

Best Use Cases for Aliphatic Coatings: 

• Stadium walkways and public plazas 

• Decorative or themed environments 

• Roofing systems requiring long-term color retention 

• Exposed steel or fiberglass surfaces 

• Exterior balconies and pedestrian areas 

• Automotive environments 

• Color-specific assets 

Which Coating Should You Choose? 

It ultimately comes down to your project’s priorities: 

• Need rugged durability and chemical resistance at a lower cost? Aromatic is likely your best choice. 

• Concerned with long-term aesthetics and UV exposure? Aliphatic is worth the investment. 

  
  

Rather than viewing one as superior to the other, it’s more accurate to see them as tools in a toolbox. When selected and applied correctly, each type delivers long-lasting protection and peace of mind. 

Let UMI Coatings Help You Decide 

At UMI Coatings, we pride ourselves on delivering innovative, high-performance solutions built on real-world expertise. Whether you’re lining a tank, coating a rooftop, or protecting automotive assets, our team is here to help you choose the right system for your needs. 

Have a project in mind? 

Contact our team to get personalized support and product recommendations.