Chemical Compatibility with Bleach

Hi,

The more information you give us the better. Tell us what the part does. pictures. environment. quantity.

You can't tell us too much.

First step is to contact the plastic manufacturers. (The people who make the raw material, not sheet or slab that you might be using.) They have excellent "compatability" information and will readily provide you with a "solution" to your specific application.

Secondly, at that thickness you might consider a composite structure where the surface in contact with the bleach is "super resistant" while the majority of the part provides mechanical strength.

From memory though, most plastics have issues with high pH for extended periods of exposure.

Please explain why FDA approval is necessary. Is bleach only part of the process? Like is this a sight glass on a food processing vat and thus only temporarily exposed to bleach?

Also, could you use shaped glass for the item? (Suitable toughened and laminated.)

Thanks for the suggestions. The FDA approval is required because this component is used in a medical instrument. I tried briefly to contact G.E. about their Noryl but the links became so convoluted that I gave up. I will have to try again to talk with a material supplier. The part is not immersed in bleach; it is occasionally washed down to disinfect that area of the machine. Unfortunately, this is a production issue that got through and I don't have the option of redesigning the part (which I do think it needs) at this point. Some plastics provide much better bleach resistance than stainless steel and with all the material being removed it might have been better to design it as a thermoformed part. If the instability after machining is still a problem that might be the next alternative.

Just a hunch, but I bet HDPE 2 would hold up pretty well.. That's what they use to make the bottles they sell it in.

Thanks gagetman. Yes, I did look at this material but the dimensional stability becomes an issue. The machine shop will not guarantee the dimensions unless they inspect the part in a constrained manner. They know that once they let it go it could go anywhere.

It might help to anneal the material in mineral oil before and after machining.

Still don't know what it does?????

I would try uhmw stable with bleach and if u ge the pebble finish i beleave its called sanilite used for cutting boards in most every kitchen

CPVC

Almost all glass surface after crystallization will not be effected by bleach. Enamel glass are cheap and is in suspension form which is used in cast iron bath tub in 50 to 80 and are still used in few countries in Europe.

Other item is high density poly propylene in organic side. Teflon also may work. Krypton tape from Dupont you can test out that may meets your requirements

Consider PPS, PEEK, (excellent dimensional stability for both but not cheap) as well as UHMW.

Are you looking for a metal or plastic part? We use 316L stainless steel for the best results when dealing with bleach. If you are looking for plastic, I would recomend looking at PEEK. It is highly stable and very chemically resistive