Desmodur N 3300 – Product Overview and Technical Data Sheet

Apr 03 , 2026

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Desmodur N 3300 is a solvent‑free aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI) trimer. Manufactured by Covestro (formerly Bayer MaterialScience), it is widely used as a high‑performance hardener in two‑component polyurethane coating systems. Unlike aromatic isocyanates, this product delivers excellent light stability and resistance to yellowing, making it the preferred choice for outdoor and high‑grade industrial applications.

Key Technical Parameters of Desmodur N 3300

The performance of any polyurethane coating depends heavily on the hardener’s specifications. Below are the certified values for this product, all determined according to DIN EN ISO standards.

Parameter	Value	Test Method
NCO content	21.8 ± 0.3%	DIN EN ISO 11909
Viscosity at 23°C	3000 ± 750 mPa·s	DIN EN ISO 3219/A.3
Hazen colour value	≤ 40	DIN EN 1557
Free HDI monomer content	≤ 0.15%	DIN EN ISO 10283
Density at 20°C	approx. 1.16 g/ml	DIN EN ISO 2811
Flash point	approx. 158°C	DIN 22 719

These figures indicate a product with consistent quality and low residual monomer content, which improves safety during handling and reduces VOC emissions in end‑use applications.

Performance Advantages of Desmodur N 330

1. Outstanding weather resistance

Because the aliphatic HDI trimer structure contains no aromatic rings, coatings cured with desmodur n 3300 show exceptional resistance to UV radiation. Gloss retention and colour stability are maintained even after years of outdoor exposure. This property is critical for automotive topcoats, architectural finishes, and transportation equipment.

2. Superior chemical resistance
The high crosslink density provided by the isocyanurate ring structure gives cured films excellent resistance to acids, alkalis, fuels, and many industrial solvents. This makes desmodur n 3300 a reliable choice for chemical plant equipment, storage tanks, and high‑performance floor coatings.

3. Balanced mechanical properties
Films based on this hardener achieve high hardness (typically 2H to 3H pencil hardness) without becoming brittle. Impact resistance and abrasion resistance are also excellent, while flexibility remains sufficient for most substrate movements. Such balance is rarely achieved with simpler hardeners.

4. Solvent compatibility and formulation flexibility
Desmodur n 3300 can be diluted with esters (e.g., ethyl acetate, butyl acetate), ketones (e.g., methyl ethyl ketone, methyl isobutyl ketone), and aromatic hydrocarbons (e.g., xylene, toluene). The desmodur n3300 tds provides a detailed list of recommended solvents and their maximum permissible water content. For stable storage, always use polyurethane‑grade solvents with water below 0.05% and no active hydrogen groups. Avoid aliphatic hydrocarbons (e.g., hexane, white spirit) as they are non‑solvents and may cause phase separation.

Storage and Handling Guidelines of Desmodur N 3300

Desmodur 3300 is sensitive to moisture. It should be stored in original sealed containers at a temperature between 0°C and 30°C. If stored at low temperatures for a long period, partial crystallisation may occur. This is reversible by carefully warming the container to 30–50°C under agitation. Do not use direct heat or open flames.

When diluting the product, do not reduce the solid content below 40%, otherwise turbidity or sediment may appear after several weeks. This is due to the limited solubility of the isocyanurate oligomers in certain solvents at low concentrations.

Safety Precautions of Desmodur N 3300

As with all isocyanate products, proper personal protective equipment (PPE) must be worn during handling – including nitrile gloves, chemical goggles, and an organic vapour respirator. Ensure adequate ventilation. In case of skin contact, wash immediately with soap and water. For spills, absorb with inert material and dispose of according to local regulations.

Always request the current safety data sheet (SDS) before first use. The desmodur n3300 tds focuses on technical properties, but the SDS provides essential health and environmental information.

Typical Applications of Desmodur N 3300

Automotive OEM clearcoats and basecoats
Automotive refinish topcoats
Industrial metal coatings
Plastic coatings for electronics and appliances
High‑performance wood finishes
Anti‑graffiti coatings
Aerospace primers and topcoats

In each of these fields, desmodur n 3300 delivers a combination of gloss, durability, and chemical resistance that is difficult to achieve with other hardener types.

Conclusion

Whether you are a formulator seeking reliable performance or a buyer looking for consistent quality, desmodur n 3300 stands out as a proven, versatile aliphatic hardener. For detailed processing parameters and specific solvent blends, refer to the official desmodur n3300 tds from Covestro. Always store desmodur 3300 correctly and follow safety guidelines to get the best long‑term results.

Eric

Vice Chairman of the Coatings and Adhesives Association
Senior New Materials R&D Engineer
Bachelor of Engineering
General Manager
Professional Experience: With 10 years of experience in the fine chemical industry, the team has served over 10,000 clients. Committed to providing one-stop fine chemical services for global clients and helping them optimize the selection of chemical materials.

References

This is the first one.

Introduction and Application Scenarios of ERICW Oxidized Wax