Desmodur ultra N 3900

Desmodur® ultra N 3900 is a low-viscosity, aliphatic polyisocyanate resin based on hexamethylene diisocyanate (HDI). It is used primarily as a hardener in weather-stable coating systems.

Key Characteristics:

• Chemical Composition: Aliphatic polyisocyanate based on HDI
• Primary Use: Hardener for weather-stable coatings
• NCO Content: 23.5 ± 0.5%
• Viscosity at 23 °C: 730 ± 100 mPa·s
• Hazen Color Value: ≤ 40
• Monomeric HDI Content: < 0.10%
• Equivalent Weight: Approx. 179
• Flash Point: Approx. 203 °C
• Density at 20 °C: Approx. 1.15 g/cm³

Solubility:

Desmodur® ultra N 3900 is compatible with several solvents including ethyl acetate, butyl acetate, 1-methoxypropylacetate-2, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, toluene, xylene, and solvent naphtha® 100. Aliphatic hydrocarbons are not suitable as solvents. It should not be thinned below a solids content of 40% by weight.

Compatibility:

Compatible with various Desmodur® and Desmophen® products, but not compatible with Desmophen® 650 and 651.

Applications:

• High-Solids Systems: Ideal for automotive refinishing, transportation coating, and plastics coating.

Storage and Handling:

• Storage Conditions: Store in original sealed containers at 0 - 30 °C, protected from moisture, heat, and foreign material. Avoid prolonged storage at high temperatures or significant lower temperatures. Solidification at low temperatures is reversible by gentle heating.
• Shelf Life: Nine months from the date of shipment under recommended storage conditions. Testing is recommended if the product is used after this period.

Safety and Regulatory Information:

• Usage: Primarily for industrial or trade applications; not suitable for DIY applications.
• Safety Measures: Handling requires appropriate protective measures due to reactive polyisocyanates and residual monomeric HDI.
• Labeling and Compliance: The product data sheet is valid with the latest safety data sheet, which contains updated safety-relevant information.

General Notes:

• The product is not intended for medical devices or other specifically regulated applications unless agreed upon with Covestro.
• The provided information does not guarantee behavior during processing or use, and users should conduct their own testing to determine suitability for their specific applications.

For more detailed technical information or specific inquiries, contacting Covestro directly is recommended.