how to prevent the blooming of EPDM rubber

Question

how to prevent the blooming of EPDM rubber

Axe1004 (Chemical)

(OP)

28 Feb 12 15:43

this happens when a cured EPDM rubber was assembled in a truck and washed it with the water and car soap.

btrueblood (Mechanical) · Answer 1 · 2012-02-28 15:48:01

Do you mean un-cured rubber?  I'd guess you'd want to re-mill it before curing, at a minimum.

I don't think there is much you could do about bloom in cured rubber.  It's a function of what is in the rubber, and you can't do much after curing it other than let it leach out if it's going to.

Is this a sulfur cured epdm?  You could think about switching to a peroxide cure...

btrueblood (Mechanical) · Answer 2 · 2012-02-28 15:53:57

Realizing you might be unsure if this is a real bloom or not, read:

http://www.hallstar.com/techdocs/The_Characterization_and_Causes_of_Bloom.pdf

Axe1004 (Chemical) · Answer 3 · 2012-02-29 01:11:34

@btrueblood

thanks for the information, that really help.

it looks like it is a surface contamination, but i have to conduct some testing based on the info that you gave to me.

GrahamBennett (Materials) · Answer 4 · 2012-03-02 11:37:37

Axe, if the sulphur content is higher than about 1.5phr then the bloom is likely to be sulphur. I have seen EPDM compound formulations that contain wax. This is totally unnecessary in EPDM. If either or both of these is the case there is nothing you can do until all of the excess material has bloomed out (likely to take years).

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how to prevent the blooming of EPDM rubber