Hydrophobic Silica - compilant to FDA 21 CFR 177.2600

[UweT]

Hello.

I found this helpfull forum during my

http://www search.

I am a enigneer for rubber compounding in Germany.
I have to develop a white EPDM compound for food contact.

My problem is to find a silica filler, that is hydrphob, this means treated with silan by the producer,
or a single silane (to mix it together with untreated silica in our internal mixer)
that complies with FDA 21 CFR 177.2600.

This is because of the parts should have a low water swelling and good abrasion resistance.

Or are there any other opportunities.

Uwe from Germany

 

[GrahamBennett]

Degussa manufactures pre-reacted silicas and silanes and markets them under the Coupsil tradename.

 

[tom1953]

I don't believe that any silane coupling agent is compliant with 21CFR 177.2600. I wish there was! If there is any info suggesting that any silane IS FDA-compliant, please post the info.
Good luck, Uwe!

 

[GrahamBennett]

Tom's right, there are no silanes that meet FDA reg 21. However, you could use polyethylene glycol (PEG400) as a plasticiser for the silica.

 

[UweT]

Hello all,

thanks for the notes.

Does anybody know, if it is possible to use maleic anhydride in FDA 21 cfr 177.2600 conform compounds.
With this it is also possible to combine silica with the polymerchain.

There are some special EPDM grades availiable with maleic anhydride in it.

Uwe

 

[GrahamBennett]

Maleic acid and anhydride are not listed, but fatty acids and hydrated fatty acids are. Personally, I would use the lowest cost grade of EPDM I could get away with.