What the table actually measures
A resistance table normally states how a test piece is doing after a set time in a pure medium, at a set temperature, with no mechanical load. Three of those conditions rarely hold in reality.
Temperature is the most important one. Resistance that holds at 20 degrees can be gone at 60. A plastic that stands up to an acid at room temperature can break down in the same acid when it is hot, and the table shows only the one row unless you read carefully.
Stress cracking, the quiet cause
The most common chemical damage is not dissolution but stress cracking. The material looks undamaged, until the part standing under load cracks after weeks or months. Load plus medium together does what neither load nor medium does on its own.
PC, PSU, PPSU and PEI are all known for it, and the trigger is often something innocent: the wrong cleaning agent, a cutting fluid, an adhesive. Check what is used in operation and during assembly, not only what is in the process.
Practical rule: if the part has internal stresses from machining, the risk is higher. Stress relieving between roughing and finishing is cheap insurance on a part that will sit in a chemical environment.
A rough ranking
The fluoropolymers, that is PTFE, PFA, FEP, PVDF and ECTFE, take more than anything else we carry, and PTFE in practice takes everything except molten alkali metal and fluorine. The polyolefins PE and PP are surprisingly tough for the price and are the standard choice for tanks and tubes. PVC handles a lot but is limited by the temperature rather than by the chemistry.
At the other end: nylon does not take strong acids, POM does not take acids or strong bases, and polycarbonate does not take alkalis or many solvents. All three are excellent materials, just not in a chemical environment.
Before you order
Do you have the medium, the temperature and the concentration? Send them to us and we will check against the supplier's resistance data instead of leaving you to interpret a general table. If the combination is unusual, we would rather say we do not know than guess.