I agree, "Santoprene" is the probably the best bet, but I thought it was a Thermo Plastic Vulcanate (TPV).
I think Advanced Elastomers have an exclusive on highly vulcanised TPVs (over 95% cross linked) due to patent protection, so they might be the only source.
Bayer and BASF could both supply info on PU, and Dupont and DSM could supply info on TPE.
I have no info on the EtO sterilizable (3x). Radiopaque. Biocompatable of any of these. You might need to get onto their technical departments to get this info. I expect most salesman will just give you a blank stare and platitudes.
You can enquire about the shore hardness from any salesman for these products or via the manufacturers websites as easily as I can. Your probably getting paid to do it. I'm not, so over to you.
Regards
pat
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.