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TDS: Polyurethane MDI (PU) [Polyester]

Make informed choices using our technical data insights.


Polyurethane MDI (PU) [Polyester]

General Information:

  • Product Name: MDI Polyester Polyurethane (PU) Elastomers
  • Classification: Elastomeric polymer, thermoset
  • Composition: Derived from methylene diphenyl diisocyanate (MDI) and polyester polyols


Typical Properties:

  • Density: 1.12 – 1.24 g/cm³ (depending on formulation)
  • Tensile Strength: 25 – 55 MPa (based on formulation)
  • Elongation at Break: 250 – 600%
  • Tensile Modulus: 18 – 110 MPa
  • Hardness: Shore A 70 – Shore D 65
  • Tear Strength: 50 – 170 kN/m
  • Compression Set: 5 – 30%
  • Hydrolytic Stability: Inferior to polyether-based PUs but acceptable for many applications

Features and Benefits:

  • Abrasion Resistance: Exceptional resistance to wear and tear, often superior to polyether-based PUs for specific applications.
  • UV Resistance: Generally, polyester PUs exhibit better resistance to UV degradation than polyether counterparts.
  • Good Mechanical Properties: Robust mechanical strength suitable for high-stress applications.
  • Chemical Resistance: Particularly resistant to oils, greases, and many solvents.
  • Heat Aging: Better heat ageing characteristics compared to polyether-based PUs.



  • Industrial: Rollers, bushings, drive belts, especially in oil-rich environments.
  • Automotive: Tires, gaskets, seals, and belts.
  • Mining and Construction: Components exposed to abrasive conditions, liners, and hydrocyclones.
  • Sporting Goods: Rugged footwear soles, mountain bike tires.
  • Medical: Some external prosthetics, protective equipment.
  • General Purpose: Outdoor components, protective films, and coatings.

Processing Methods:

  • Casting: Suitable for custom geometries and parts.
  • Injection Moulding: Ideal for large scale component production.
  • Reaction Injection Molding (RIM): Used for detailed or larger components.


Environmental Impact and Recycling:

  • As with most thermosets, MDI polyester PU elastomers are difficult to recycle compared to thermoplastics.
  • Efforts should be made to minimise waste through efficient production and by repurposing production scrap.
  • Research into chemical recycling methods, such as glycolysis, continues to enhance their recyclability.

Storage and Handling:

  • Store in a dry, cool location, shielded from UV light which can degrade the material.
  • Raw materials, especially MDI, should be handled with caution due to their reactivity and potential hazards.


Safety Information:

  • When fully cured, MDI polyester PU elastomers are generally considered non-toxic.
  • During the production process, proper ventilation is necessary, and protective equipment should be worn to avoid exposure to isocyanates.
  • Flammable in nature. If incinerated, they can emit harmful gases; therefore, suitable fire prevention and safety measures should be observed.

Note: This technical data sheet offers a general overview and typical values for MDI polyester PU elastomers. Real specifications might differ depending on the manufacturer and specific product grade. Always consult the manufacturer’s data sheets for accurate information on a particular product.

Disclaimer: The information presented is “as is” without any guarantees. Users should conduct their tests and evaluations for specific applications.

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