EPDM

Ethylene-propylene-diene rubber (EPDM)

EPDM is a synthetic terpolymer rubber made from ethylene, propylene and a small amount of diene. Thanks to its saturated polymer backbone, EPDM is particularly resistant to weathering, ozone and ageing, and remains elastic even when used outdoors for many years.

Properties of EPDM

• very good resistance to UV radiation, ozone and weathering
• good resistance to oxygen, water, hot water and steam
• good compatibility with glycol-based brake fluids
• good resistance to many diluted acids, alkalis and polar media
• Poor resistance to mineral oils, greases, fuels and many hydrocarbons – NBR or FKM are usually used here
• Good elastic recovery and vibration damping

Depending on the mixture, EPDM compounds typically cover a temperature range of approximately -30 °C to +120 °C. Specially designed grades allow higher temperatures, especially in hot water and steam circuits. In closed hot water systems, depending on pressure, medium and approval – temperatures of up to approx. +150 °C are possible for short periods, and in special cases even higher; the relevant material data and approvals are decisive here.

Cross-linking and compression set

EPDM can be cross-linked using sulphur or peroxide

• Sulphur-cross-linked grades often offer good dynamic properties and are cost-effective.
• Peroxide-cured EPDM grades generally exhibit improved compression set and higher temperature resistance, making them particularly interesting for permanently compressed seals (e.g. O-rings, flat seals, profiles).

Processing and bonding

Due to its non-polar molecular structure, EPDM is difficult to bond. A reliable connection to other components is therefore often achieved via:

• mechanical anchoring (groove, form fit),
• vulcanisation on a substrate (metal-rubber connections) or
• special primer and adhesive systems

EPDM can be easily extruded and processed into profiles, hoses, sealing lips, moulded parts and construction profiles. The hardness range of typical EPDM seals is usually between approx. 50 and 80 Shore A.

Typical applications of EPDM

EPDM is one of the most important sealing materials in industry and vehicle construction. Typical areas of application are:

• Glycol-based brake fluids – seals and sleeves in brake systems
• Hot water and steam applications – hoses, seals and O-rings in heating and sanitary engineering, washing systems, process water
• Household appliances – hoses and seals for washing machines, tumble dryers, dishwashers
• Automotive industry – door, window and boot seals, window surrounds, coolant hoses; EPDM is one of the most widely used sealing materials in vehicle construction in terms of quantity
• Construction and facade technology – EPDM profiles, films and seals for windows, facades, roofing membranes, waterproofing membranes
• Pneumatics and general mechanical engineering – Seals, O-rings, diaphragms, vibration elements
• Drive belts and conveyor belts – where temperature and ozone resistance are more important than oil resistance

Thanks to its combination of weather resistance, suitability for hot water and steam, good elasticity and wide availability, EPDM is now a standard material for seals, O-rings, profiles and customised moulded parts in many industries.

Disposal

According to the “Regulation on the European Waste Catalogue (AVV)”, the waste product can be classified according to Chapter 7 “Wastes from organic chemical processes” and here under waste code 07 02 99. Both waste codes represent waste classified as non-hazardous.

They can therefore be disposed of in normal household quantities with normal household waste. Please use the container provided by your public waste disposal authority for residual waste as the appropriate disposal container.

Synonyms: APTK