This reference https://www.finemech.com/tech_resources/chemical_resistance.pdf suggests that PTFE should be good for caustic soda (sodium hydroxide) up to 50% and up to 120C.
I'm not suggesting you re- or double-post, but, FYI, there is a Rubber Engineering Forum (http://www.eng-tips.com/threadminder.cfm?pid=335) that is monitored by rubber industry experts. This question might have been better posted there.
Millable (solid, vulcanized) polyester urethanes with hydrolysis stabilizer can have very good, but finite, resistance to 80-90C water, the lifetime being depending on the type and level of hydrolysis stabilizer. Also, there are some new polyester grades being developed that have excellent...
FWIW, fumed silica does generally improve properties and abrasion resistance in vulcanized rubber compounds, typically with some silane coupling agent assisting.
tom
Was the TPU a polyether or polyester type? Polyester types will be very much less affected by oil than polyether types. A recent study I did showed 1-8% swell with polyester millable (solid, peroxide vulcanized) urethanes vs. 20-40% for polyether millable urethanes.
Also, a vulcanized, millable...
Unfortunately, I don't have any first-hand knowledge of NSF 61, but do know that companies (custom mixers and product manufacturers) have developed compounds that have been tested or certified to be NSF 61 compliant. I don't know if there's a listing of materials that are NSF61-compliant.
Sorry...
Presumably you're talking about balls made out of polybutadiene rubber (BR). This would mean a rubber compound which probably contains, besides the BR itself, curatives (peroxide or, more commonly, sulfur and sulfur-containing accelerators), fillers, plasticizers, process aids, and...
Maybe a material that's better for abrasion resistance and tearing, like urethane, would give longer life than silicone (which isn't known for either of these properties)
It's a delicate balance, to be sure. I suggest you consult with your EPDM supplier for assistance. Uniroyal used to have a nice tech service center with an extrusion/hot air/microwave line where they'd fine-tune curing and foaming of EPDM compounds. That product line is now owned by Lion...
FWIW, this might be a better topic for the Rubber Engineering forum (http://eng-tips.com/threadminder.cfm?pid=335).
btrueblood, my experience (and quite a few references I've seen) is that urethanes generally have higher tear strength than nitrile rubber, and not all urethanes are "too slippery...
It sounds like the UV protectants you're using are not adequate for your needs. Is this a new problem or a continuing one? If it's new, then maybe something has changed in the UV additives or the HDPE. If it's a continuing problem, then maybe looking at different types and/or amounts of UV...
EPDM rubber can be very resistant to UV when a significant amount of carbon black is included in the formula. EPDM is widely used for roofing, which typically will last several decades.
There are chemical resistance charts on the Internet which should be of use, including:
http://www.coleparmer.com/techinfo/ChemComp.asp
http://calgasket.com/TLARGI%2022test5.htm
http://www.wildenpump.com/specs/Chemical-Resistance-Guide.pdf
tom
Sorry for my apparent indiscretion, but I wanted to point out a polymer that a customer had recently done some light transmission testing on, and gotten some good results, and thought I'd mention these types of products in case the original inquirer wanted another option to consider.
For future...
