Desmodur® E 21

Desmodur® E 21 is an aromatic polyisocyanate prepolymer based on diphenylmethane diisocyanate (MDI). It is primarily used for two purposes:

(A) As a binder for the formulation of moisture-curing, one-component coatings and adhesives. (B) As a hardener for hydroxyl-bearing co-reactants.

Here are the key specifications and characteristics of Desmodur® E 21:

Characterization:

• Type: Aromatic polyisocyanate prepolymer based on MDI.
• Form: Solvent-free liquid of medium viscosity.

Specification:

• NCO Content: 16.0 ± 0.7%
• Viscosity: 5,400 ± 1,300 mPa·s at 25°C
• Equivalent Weight: 251 - 274
• Flash Point: > 250°C
• Density: Approximately 1.15 g/ml at 20°C

Solubility/Thinnability:

• Compatible with solvents such as ethyl acetate, butyl acetate, 1-methoxypropylacetate-2, xylene, Shellsol® A, and Solvesso® 100.
• Solutions formed must be tested for their storage stability. Only PU grade solvents should be used, and the solvent should not contain reactive groups.

Compatibility:

• Compatible with Desmophen®/Baycoll® polyols, other Desmodur® products, and flexibilizers.

Properties/Applications:

• Suitable for formulating moisture-curing one-component systems, which can be used as primers and sealers for porous substrates to provide protection against moisture, oil, fuel, and other chemicals.
• Can be used as a binder in the formulation of synthetic resin mortars.
• Yields tough but flexible, wear-resistant coatings and sealers when combined with suitable Desmophen polyols.
• Suitable for formulating solvent-free moisture-curing one-component adhesives or two-component adhesives when combined with Baycoll®.

Storage:

• Should be stored in its original sealed container at room temperature (approximately 23°C).
• Protect from moisture, heat, and foreign materials.

Desmodur® E 21 offers versatility in various coating and adhesive applications, providing durable protection and excellent adhesion properties.