What is EPDM?
EPDM is a synthetic rubber made from a mixture of ethylene, propylene and a third monomer (diene). This chemical structure gives the material unique properties:
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High elasticity: EPDM retains its flexibility even at low temperatures.
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Outstanding weather resistance: Resistant to UV radiation, ozone, weathering and moisture.
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Chemical resistance: Unaffected by a wide range of chemicals, including alkaline solutions and weak acids.
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Thermal stability: Resistant to temperatures from -40 °C to +120 °C, and in some special (peroxide-cured) compounds even up to 150 °C.
These properties make EPDM a preferred material in many technical applications, especially in sanitary applications.
Requirements for seals in sanitary applications
Seals in sanitary applications must meet specific requirements to ensure their function over the long term:
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Resistance to water and moisture: Permanent contact with water and damp environments calls for materials that do not swell or become brittle.
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Drinking water approval: Seals must be free from harmful substances and meet strict hygiene standards such as KTW-BWGL, DVGW or W270.
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Temperature resistance: Sanitary installations include both cold and hot water pipes. Seals must work reliably in both temperature ranges.
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Resistance to chemicals: Cleaning agents, disinfectants and other chemicals must not attack the seals.
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Durability: Frequent opening and closing of fittings, as well as pressure and temperature fluctuations, require high fatigue resistance.
EPDM meets all these criteria and is therefore one of the preferred elastomers for sanitary seals.
Properties of EPDM in sanitary applications
EPDM offers a number of advantages that make it ideal for sanitary applications. Below we go into the technical details:
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Temperature resistance: EPDM withstands temperatures from -40 °C to +120 °C, which makes it ideal for hot and cold water applications.
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Resistance to water and moisture: The molecular structure of EPDM prevents water from penetrating, which protects it against swelling, leaks and deformation.
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UV and ozone resistance: Unlike many other materials, EPDM withstands long-term exposure to UV, ozone and weathering without cracking or becoming brittle.
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Chemical compatibility: EPDM is resistant to chlorinated water, weak acids and alkaline solutions, which makes it ideal for sanitary systems that are disinfected regularly.
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Good compression set: EPDM seals retain their shape even under long-term load, which ensures reliable sealing.
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Hygienic safety: EPDM meets the requirements of important certifications such as KTW-BWGL and DVGW, which are essential for drinking water applications.
Comparison with other materials
In sanitary applications, EPDM competes with other materials such as NBR (nitrile rubber), silicone and PTFE. Here is a comparison:
| Property | EPDM | NBR | Silicone | PTFE |
|---|---|---|---|---|
| Temperature resistance | -40 °C to +120 °C | -30 °C to +100 °C | -60 °C to +200 °C | -200 °C to +260 °C |
| Chemical resistance | Very good | Good | Limited | Excellent |
| UV and ozone resistance | Excellent | Moderate | Very good | Very good |
| Cost | Low | Low | Medium | High |
As the table shows, EPDM is a cost-effective, high-performance solution for many sanitary applications, especially where UV and ozone resistance are required.
Applications of EPDM flat seals in sanitary technology
EPDM seals are used in a wide variety of sanitary applications:
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Fittings and valves: Ensuring a tight connection, even with frequent use.
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Drinking water pipes: EPDM meets the hygiene requirements for drinking water systems and is therefore a preferred choice.
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Waste water and drainage systems: Its chemical resistance makes EPDM ideal for contact with cleaning agents and other chemical substances.
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Shower and bathroom fittings: Resistant to temperature fluctuations and exposure to water.
Care and maintenance
To maximise the service life of EPDM seals, a few maintenance measures should be observed:
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Regular checks for cracks, discolouration and embrittlement.
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Avoiding contact with mineral oils or greases, which can attack EPDM.
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Gentle cleaning with mild cleaning agents.
Conclusion
Thanks to its outstanding properties such as temperature resistance, chemical resistance and hygienic safety, EPDM is an ideal material for flat seals in sanitary applications. It meets the strict requirements of this industry and offers a durable, cost-efficient solution for numerous applications. With the right care and maintenance, the service life of EPDM seals can be extended even further.