EPDM Material shrinkage

[qaqc1]

Has anybody ever experienced shrinkage in EPDM material. We have gaskets made of EPDM. The cross-section of the gaskets is "C" shaped & they are circular. We have observed over a period of time the diameter shrinks by about 2% over six months.
Any suggestions on how to fix this.

 

[berti]

Hi all,

there could be two possible reasons to consider:

- loss of plastiziser, which is quite often lots of paraffinic oil in EPDM - check if there is also a weight loss after the 6 months ?

- frozen cristallinity - from ethylene segments - which relax over a long time. Heat a new gasket up to >130 °C for a short time - some minutes - and let it cool down slowly to room temp. If the shrinking occurs then, ask your supplier to use another EPDM - with less ethylene - and/or to deliver the material after the described "postcuring" process with the requested size.

Let me know about your results !!!

Berti

 

[qaqc1]

Thank you "Berti" for the information. I am not sure if I will be able to reply to you immediately on the results.

regards