Finding Silicone Rubber compatible with Epoxy and Polyurethane Resins

[Marouane]

Hi Dears,

I am looking for a silicone rubber that compatible with my epoxy and polyurethane resins. The reason I am asking this is that I used a Polyaddition Silicon named ''ESSIL 291'' from Axon. However, after 5 castings, a white layer started to appear on my silicone which with more casting turned into a thick yellewish layer.

My epoxy Resin is called: Fast Cure Graffitte Resin. See:

https://shop.grresin.com/en/product/p47830592

Please keep in mind that my epoxy is two parts. Part A is bisphenol-A-(epichlorhydrin) epoxy resin. Part B is 3-aminomethyl-3,5,5- trimethylcyclohexylamine



My Polyurethane Resin is:

https://specialtyresin.com/products/model-pro-off-white-slow

Keep in mind that my epoxy is two parts. Part A consists of two chemicals: (Diphenylmethane-4,4’-diisocyanate(MDI)), and ( 2,2,4-trimethyl-1,3-pentanediol diisobutyrate).
Part B consists of three chemicals: (N, N, N’,N’-tetrakis(2-
hydroxylpropyl)ethylenediamine), (2,2,4-trimethyl-1,3-pentanedioldiisobutyrate), and (Diethylene glycol)

I am looking forward to hearing from you.

Best regards,

 

[Compositepro]

It is well known that silicone rubber degrades in contact with unfurled epoxy resins. The only solution that I am aware of to prevent this is to prevent co tact between them by using a FEP release film to cover the silicone. I believe that FEP can be thermoformed to a shape with vacuum and a heat gun.