What is DDI Used For? Applications of Dimer Acid Diisocyanate in Modern Polyurethane Systems

1. Introduction: What is DDI?

Dimer Acid Diisocyanate (DDI) is a high-performance aliphatic diisocyanate derived from dimer acid, typically produced from plant-based fatty acids. Compared with conventional aromatic isocyanates such as TDI and MDI, DDI offers superior flexibility, excellent weather resistance, and low toxicity — making it a next-generation raw material for eco-friendly polyurethane formulations.

Its long-chain aliphatic backbone provides outstanding hydrolytic stability, UV resistance, and low-temperature elasticity, positioning DDI as a preferred choice for demanding applications that require both durability and sustainability.

2. Key Advantages of DDI in Polyurethane Applications

Procurement engineers and formulators choose DDI because it solves several common issues found in traditional isocyanate systems:

• Superior Flexibility and Low-Temperature Performance
  The long aliphatic chain structure gives polyurethane elastomers excellent elasticity even under sub-zero conditions.
• Outstanding UV and Weather Resistance
  Ideal for outdoor and marine coatings, DDI-based systems maintain gloss, color, and mechanical integrity over time.
• Excellent Chemical and Hydrolytic Stability
  DDI provides improved resistance to moisture and oxidation, ensuring long-term stability in harsh environments.
• Low Volatility and Reduced Toxicity
  As an aliphatic diisocyanate with low vapor pressure, DDI is safer to handle and suitable for low-VOC and high-purity applications.
• Renewable & Sustainable Source
  Derived from bio-based dimer acids, DDI supports the shift toward green and sustainable polyurethane chemistry.

3. Main Applications of Dimer Acid Diisocyanate (DDI)

(1) Polyurethane Elastomers

DDI is used to produce high-performance PU elastomers with superior elasticity, wear resistance, and hydrolysis stability. Typical applications include:

• Industrial rollers, seals, and vibration-damping parts
• Flexible coatings and protective films
• High-end sports and automotive components

(2) Weather-Resistant Coatings

DDI-based aliphatic systems are widely applied in:

• Outdoor and marine coatings that demand UV resistance and long-term gloss retention
• Industrial anti-corrosion coatings requiring high adhesion and flexibility
• Topcoats in metal, plastic, and wood protective systems

(3) Adhesives and Sealants

DDI significantly enhances adhesion strength, elongation, and durability in moisture-curable polyurethane adhesives. It is particularly suited for:

• Structural and construction adhesives
• Electronic potting compounds
• Flexible sealants for automotive and aerospace use

(4) Electronics and Optical Materials

With its high purity and low migration characteristics, DDI is ideal for:

• Encapsulation resins and optical-grade polyurethane coatings
• Flexible printed circuit boards (FPCs)
• Protective coatings for sensors, lenses, and LED devices

(5) Bio-Based & Degradable Polyurethanes

Because of its renewable origin and low toxicity, DDI is increasingly used in the research and production of biodegradable or partially bio-based polyurethane systems, supporting sustainability initiatives in materials science.

4. Why DDI Solves Formulation Challenges for Manufacturers

For polyurethane manufacturers and R&D formulators, DDI offers a unique combination of reactivity and flexibility. Its linear molecular structure allows precise control over crosslink density, enabling designers to tailor mechanical properties for both soft and rigid applications.

Moreover, compared with other aliphatic diisocyanates such as HDI or IPDI, DDI provides:

• Lower toxicity and handling risk
• Lower moisture sensitivity during processing
• Better compatibility with polyols containing long-chain or hydrophobic segments

These advantages make DDI a cost-effective and performance-balanced solution for high-end polyurethane applications.

5. Partner with a Reliable DDI Supplier

When sourcing Dimer Acid Diisocyanate, consistency and technical reliability are critical. Choosing a trusted DDI supplier ensures:

• High purity and controlled NCO content
• Consistent batch quality for predictable curing performance
• Technical support for formulation optimization
• Safe packaging, export documentation, and stable global supply

RUIFENG POLYMER is a professional manufacturer and global supplier of polyurethane raw materials, including Dimer Acid Diisocyanate (DDI). We provide customized specifications, TDS/MSDS support, and application testing services to help our customers achieve the best performance in their polyurethane systems.

6. Conclusion

DDI is more than just another isocyanate — it represents the future of high-performance and sustainable polyurethane chemistry. With its exceptional weatherability, flexibility, and eco-friendly profile, Dimer Acid Diisocyanate continues to open new possibilities across coatings, elastomers, adhesives, and specialty polymers.

If you are developing advanced polyurethane formulations that demand durability, safety, and sustainability, DDI from RUIFENG POLYMER is your trusted choice.

To request COA and TDS, please visit RUIFENG POLYMER Contact or view product details at DDI (68239-06-5).