Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| dilute | C | D | |
| saturated | C | D |
Material comparison at 20 °C
Resistance overview
Acetal (POM) maintains a consistent rating of C across all 2 tested concentrations (dilute, saturated) of Alum (Potassium Aluminum Sulfate) at 20 °C. The fact that the rating does not change with concentration within the tested range simplifies material selection, though the boundary conditions beyond this range remain untested. However, at 50 °C the resistance rating drops, indicating that temperature must be factored into the design. For heated applications, additional testing under actual service conditions is strongly recommended.
Application context
Alum (Potassium Aluminum Sulfate) is commonly encountered in electroplating and food processing. Acetal (POM) (Polyoxymethylene (acetal)) is a thermoplastic typically used for tanks, piping, containers and liners. The compatibility between these two is therefore an important consideration for engineers and procurement teams selecting containment, transfer, or processing equipment.
Practical recommendation
Acetal (POM) has limited resistance to Alum (Potassium Aluminum Sulfate) and should only be used for short-term or intermittent contact at ambient temperature. The C rating means the material undergoes noticeable changes — swelling, loss of strength, or surface degradation — that make it unsuitable for permanent installations. For prolonged or continuous exposure, HDPE, LDPE, Nylon (PA) offer significantly better resistance and are rated A.
Did you know?
When choosing between thermoplastics for Alum (Potassium Aluminum Sulfate) service, engineers consider not just the resistance rating but also factors such as permeation rate, creep resistance, and weldability.
Materials rated A or B at 20 °C
Based on the row for dilute, 20 °C.
- Thermoplastics
- HDPE A, PP A, PVC Rigid A, LDPE A, Nylon (PA) A, Polycarbonate A, PVC Flexible A, Polystyrene A, Polysulfone A, PETG B, SAN A
- Fluoropolymers
- PTFE A, PVDF A, FEP A, ECTFE/ETFE A
- Elastomers
- EPDM A, Viton (FPM) A
- Metals
- SS 316 A, SS 304 A, Aluminium A
About Acetal (POM)
Acetal (POM) resists many organic solvents and fuels. Strong acids and oxidising agents degrade it.
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
About this data
The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.
A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.