This is more of a curiosity question since PEI filament is clearly an industrial product well outside the specs of a consumer FDM printer.
I have a project where I need some chemical-resistant properties. ASA is the one that keeps popping up in my research, but the endorsements aren’t exactly confidence-inducing. In one such blurb I read regarding its resistance to gasoline, the text said the following:
ASA is known for its excellent resistance to chemicals, weathering, and UV exposure. It’s often used as a more weather-resistant alternative to ABS. While it’s not completely impervious to gasoline, it generally holds up better compared to ABS.
That’s not exactly a ringing endorsement, since gasoline is precisely one of the chemicals my project may be exposed to. So if anyone has experience with filament that can withstand gasoline or diesel and other combustible fuels, I’d really be interested in your experience.
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As I dug deeper, the recommended filament that keeps popping up in search is PEI. Aside from the fact that this stuff is $8/oz, I’m only finding one or two manufacturers. It appears to be a product geared towards specialized industrial knowledge and specialized 3d Printers.
Here’s an interesting video on the only product I’ve found so far that’s spooled to go into FDM printer.
Check out these specs. In the video they say that it works best in a heated chamber of 220c 
Why stop there? 20c more and your printer can double as a Pizza oven. 
I’m assuming that anyone who works with this class of material is in a professional class well outside of the consumer class of printer enthusiasts, so I am very curious as to how that world lives. It’s kinda like watching guys who drive around in $2 million sports cars that I can never afford, but it sure is interesting to watch.
I did find one printer that they advertise that is purpose-built for this and for poultry sum of 125 X1 Carbons, it can be yours. Hmmm… I wonder if we pool our resources, perhaps we can negotiate a group discount. 
