Urethane can be custom formulated to achieve specific physical properties. However, with a wide variety of physical properties available for custom urethane parts and products, customers often have questions regarding the specifications and materials needed for their specific application.
To help, below is a list of frequently asked questions about custom urethane products with answers provided by the experts at PSI Urethanes.
What is durometer?
Durometer is the hardness of a non-metallic product or the gauge used to measure the hardness. The two most common elastomer durometer scales, using slightly different measurement systems, are the ASTM D2240 type A and type D scales. The A scale is for softer urethanes, while the D scale is for harder ones.
Polyester versus Polyether
The two main types of Polyurethanes are Polyester and Polyether. Each offers its own performance properties.
What is Polyester?
A chemical building block that provides good resistance to solvents as well as good mechanical properties in the final elastomer.
What is Polyether?
A chemical building block sometimes used in place of polyester that provides exceptional resilience and hydrolytic (reaction with water) stability.
What is MDI?
Methylene Di-isocyanate; A base form of urethane resin that needs non-Moca Type curatives.
What is TDI?
Toluene Di-isocyanate; A base form of urethane resin that needs Moca Type curatives.
What polyurethane material would work best for my application?
The following guide can be used to select the material most appropriate for your application.
|Guideline Selection of Polyurethane|
|Tensile (tension) Strength||Polyester||Polyether|
|Tear Strength||Polyester||Low Cost Polyether|
|Rebound||MDI Polyether||TDI Polyester|
|Low Temperature Properties||MDI Polyether||TDI Polyester|
|High Temperature Properties||TDI||MDI|
Low Cost Polyether
Low Cost Polyether
|Hydrolysis (reaction with water) Resistance||MDI Polyether||TDI Polyester|
|Heat Aging||Polyester||Low Cost Polyether|
What are some differences between thermoset urethane and thermoplastic urethane products?
The chart below highlights several differences between thermoset polyurethane and thermoplastic urethane products.
|Property||Thermoset Polyurethane||Thermoplastic Urethane|
|Heat Resistance||Holds up in temperatures of up to 250° without issue||Will soften, deform and degrade at higher temperatures|
|Hardness||Wide range of durometers available in “A” & “D” scale||Very small range in “A” scale only|
|Load Bearing Capacity||Ability to hold a great amount of weight per square inch||Unable to hold a great deal of weight without destroying material|
|Abrasion Resistance||Best for abrasive applications because of its high abrasion resistance and cut resistance||Will abrade and tear in these cases|
As you can see, there is a remarkable range of urethane physical properties to choose from allowing urethane to be used across a wide variety of applications and industries.