Material Spotlight: Elastomers

Posted: March 16, 2018 in polyurethane
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In your searches for plastics to fulfill your dream of various projects you may encounter the term “elastomers”. What are elastomers? Defined generally that is a material that “rebounds” when impacted or compressed. The rule of thumb is the material has to return to 90% of its original size 10 minutes after compression occurs. The two elastomers you’re most likely to encounter are polyurethane and rubber. Again, as a rule of thumb, polyurethane is a more expensive – but premium – replacement for rubber and outlasts rubber in most applications. Where rubber should be substituted for polyurethane is in applications with lots of vibration. That’s why you see rubber used as bushings on vehicle suspensions for example.

Rubbers and polyurethane are also defined by a wide range of hardnesses, unlike other plastic materials. Commercially sold rubber usually ranges from 40A durometer (quite soft) to 80A which is fairly rigid. Polyurethane ranges from about 52A-75D and that change in letters following the number is important. At 75D the polyurethane feels “rock” hard and it is primarily used in applications like sprockets and bushings. One major advantage to elastomers over some other plastics is that they are readily moldable. Not just injection molding, but simpler and less expensive open cast molding.

If you have questions about whether polyurethane or rubber is right for your application please contact us today.


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