Description
Polyurethane rubber is notable for its combination of hardness with elasticity, outstanding abrasion resistance and tear strength. Elastomeric urethane rubber, not to be confused with thermoplastic polyurethane, may be either ether (EU) or ester (AU) base, with the latter being the far more common of the two. It is often referred to as the "millable gum" urethane. The ester based polymer is superior in resistance to abrasion and heat, while the ether based polymer has better flexibility at low temperatures. Polyurethane is a moderately expensive material whose use is usually limited to applications that require its outstanding physical properties. Common end use applications are industrial seals, industrial rolls, O-Rings, caster wheels, gaskets, shoe soles and conveyor belts. Peroxide is the most commonly employed cure system, but sulfur curing is also possible in the extremely complex vulcanization chemistry involved in polyurethanes.
Composition
Polyurethane
Physical Properties*
| |
Excellent |
Good |
Fair |
Poor |
| Abrasion resistance |
• |
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|
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| Compression Set |
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|
• |
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| Elongation |
|
• |
|
|
| Flame resistance |
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|
|
• |
| Gas permeability |
|
• |
|
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| Low temperature flexibility |
• |
|
|
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| Tear resistance |
• |
|
|
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| Tensile strength |
• |
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|
Chemical Resistance*
| |
Excellent |
Good |
Fair |
Poor |
| Air |
|
• |
|
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| Alcohols |
|
• |
|
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| Aldehydes |
|
|
|
• |
| Concentrated acids |
|
|
|
• |
| Concentrated Bases |
|
|
|
• |
| Ethers |
|
|
• |
|
| Ketones |
|
|
|
• |
| LP Gas |
|
|
• |
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| Mineral oil |
|
• |
|
|
| Oxidation |
• |
|
|
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| Ozone |
• |
|
|
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| Silicone Fluids |
• |
|
|
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| Steam |
|
|
|
• |
| Sunlight |
|
• |
|
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| Weather |
• |
|
|
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Operating Temperature
-40 to 180 °F
*Excellent, good, fair and poor are intended to serve as general guidelines only. Actual testing in the application environment is always recommended. |