Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 1 % | C | C | |
| 10 % | C | C | |
| 30 % | C | C | |
| 50 % | C | D | |
| concentrated | C | D |
Material comparison at 20 °C
Resistance overview
NBR maintains a consistent rating of C across all 5 tested concentrations (1 %, 10 %, 30 %, 50 %, concentrated) of Potassium Hydroxide 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
Potassium Hydroxide is commonly encountered in textile processing and chemical processing. NBR (Nitrile butadiene rubber) is an elastomer typically used for seals, O-rings, hoses and flexible connections. Because Potassium Hydroxide is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.
Practical recommendation
NBR has limited resistance to Potassium Hydroxide 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?
The chemical resistance of NBR depends not only on the chemical concentration but also on exposure time, mechanical stress, and the presence of other chemicals in the mixture.
Materials rated A or B at 20 °C
Based on the row for 50 %, 20 °C.
- Thermoplastics
- HDPE A, PP A, PVC Rigid A, LDPE A, Nylon (PA) A, PVC Flexible A, Polystyrene B, Polysulfone A, PMP A, SAN A
- Fluoropolymers
- PTFE A, FEP A, ECTFE/ETFE A
- Elastomers
- EPDM A
- Metals
- SS 316 A, SS 304 A
About NBR
Nitrile rubber resists mineral oils and fuels. Ketones, esters, chlorinated solvents, strong oxidisers and ozone attack 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.