a type of polyisocyanate hardener used primarily in the formulation of polyurethane coatings, adhesives, and sealants. It is a product from Covestro, a leading producer of high-performance polymers and materials

Desmodur N75 is a type of polyisocyanate hardener used primarily in the formulation of polyurethane coatings, adhesives, and sealants. It is a product from Covestro, a leading producer of high-performance polymers and materials. Desmodur N75 is known for its versatility and excellent performance characteristics.

Key Characteristics

1. Chemical Composition:

   • Type: Aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI).
   • Isocyanate Content: Typically around 21.8% by weight.
   • Viscosity: Approximately 1000 mPa·s at 23°C.

2. Properties:

   • Weather Resistance: Excellent resistance to UV radiation and weathering, making it suitable for outdoor applications.
   • Chemical Resistance: High resistance to a variety of chemicals, including solvents and acids.
   • Mechanical Properties: Provides coatings with good flexibility and hardness.
   • Durability: Offers long-lasting protection and maintains appearance over time.

Applications

1. Coatings:

   • Automotive Coatings: Used in clear coats and topcoats for automotive finishes due to its high gloss and durability.
   • Industrial Coatings: Suitable for protective coatings on metal, plastic, and wood surfaces exposed to harsh environments.
   • Architectural Coatings: Employed in high-performance exterior paints and coatings that require long-term resistance to weathering.

2. Adhesives and Sealants:

   • Construction Adhesives: Provides strong bonding and long-lasting performance in construction materials.
   • Sealants: Used in formulations requiring flexibility and resistance to environmental factors.

Advantages

• Versatility: Can be used in a variety of formulations to meet specific application requirements.
• Performance: Offers superior weather and chemical resistance, enhancing the longevity and appearance of coatings.
• Durability: Maintains performance under harsh environmental conditions, providing long-lasting protection.

Disadvantages

• Cost: Typically more expensive than some other isocyanate hardeners.
• Handling Requirements: Requires careful handling and proper safety measures due to the reactive nature of isocyanates.

Handling and Safety

1. Personal Protective Equipment (PPE):

   • Use appropriate PPE, including gloves, goggles, and protective clothing, to avoid skin and eye contact.
   • Ensure the use of respirators or adequate ventilation to avoid inhalation of vapors.

2. Storage:

   • Store in tightly closed containers in a cool, dry place away from moisture and sources of ignition.
   • Protect from temperatures below 0°C and above 30°C to maintain product stability.

3. Safety Measures:

   • Follow all safety data sheet (SDS) recommendations for safe handling and disposal.
   • Use in well-ventilated areas to prevent buildup of vapors.