heat resistant and food safe?

I’m wondering if there exists a rubber that could be used as a seal, that’s food safe even with boiling water, and preferably injection-moldable. any ideas?

Joey

Lots of them actually. Regular old Buna-N nitrile rubber is available in an FDA approved formulation and is good for about 225 degrees F. There’s also an FDA version of viton, which is good to 4-500 degress. And of course there’s silicone, which can go over 400 degrees. All of them can be molded, and are routinely used in static and dynamic sealing applications. They all have various other properties that may make them more or less suitable depending on your specific application.

Maybe look at TPEs (Thermoplastic Elastomers)? Boiling water might be tricky, but they’re definitely injection-moldable and, in many variants, food-safe. If it’s some kind of a gasket, you’ll have to keep it lubricated with food-safe oil. Silicone is definitely food-safe – it’s completely biologically inert, so even broken off pieces won’t harm you.

You could also try a molded polypropylene seal like in Tupperware (I think those are PE, but they have essentially the same characteristics. PP is more heat-resistant and will stand up to autoclaving as far as I know).

It’s usually a pain to try and keep something as delicate and technical as a rubber seal in good condition when it’s constantly being abraded by food and water – especially if it has to be greased. You could try a redesign that would keep the seal away from the food, and go with a regular polyurethane (or similar) O-ring.

Edit: scott obviously knows a whole lot more about this than I do :slight_smile:

Actually the McMaster-Carr catalog does. :slight_smile: