O-Ring Material Selection (Nitrile / NBR / Viton)

[TRRMan]

We are in the process of developing a new product that will have a 2 year warranty. The current design uses a Nitrile o-ring which I don't think is a good choice because the product will be exposed to the weather. The seal is acting more to keep the weather out than anything else so it will not be under pressure. The product acts in a rotatary fashion but only 3-10 revolutions per day. It will be exposed to general out door enviroment, rain, snow, salt from roads etc. Would NBR or Viton be a better choice?

Thanks for the help.

 

[edrush]

It looks like ethylene-propylene (EPDM) rubber is your best bet:

http://www.applerubber.com/products/o-rings.cfm