Technical document

Features and uses of EPDM

2024-11-14 16:10:17 EPDM

Molecular Structure and Properties of EPDM


EPDM is a copolymer of ethylene, propylene, and a small amount of non - conjugated diolefin. The main molecular chain, mainly composed of saturated hydrocarbons, endows it with high chemical stability. During synthesis, the ratio of ethylene and propylene units, as well as the type and content of diolefin, can be adjusted, enabling control over properties like hardness, flexibility, and vulcanization speed to meet diverse application needs.

Characteristics of EPDM

Chemical Stability


  • Resist Chemical Attack: Its highly saturated molecular backbone gives excellent resistance to most polar chemicals such as alcohols, acids, bases, etc. It can maintain stability in acid - alkali environments, like in reactor sealing and pipeline connections in chemical production.

  • Solvent Resistance: However, it is less stable in aliphatic and aromatic solvents and mineral oils. These solvents can penetrate rubber molecules, causing expansion and softening. Special considerations are needed when exposed to such solvents, e.g., in fuel delivery systems.


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Aging Resistance


  • Ozone Resistance: EPDM is known as "non - cracking rubber" with outstanding ozone resistance. In high - ozone environments like automobile engine compartments, EPDM rubber tubes and seals can work statically for a long time without cracking.

  • Weather Resistance: It has excellent weather resistance and can be used in natural environments for a long time. As a roof waterproof material, EPDM waterproof coils can effectively prevent rain leakage for over 25 years under normal use.

  • Heat Resistance: EPDM can be used at 150℃ for a long time and withstand 200℃ high temperature intermittently. It can maintain good elasticity and mechanical strength in high - temperature applications, such as in automotive radiator hoses and industrial heat exchanger seals.

Resistance to Water Steam and Superhot Water


  • Water Vapor Resistance: EPDM is hydrophobic, and water vapor hardly interacts with it physically or chemically. It can prevent steam leakage in industrial steam piping systems and perform well in humid environments like bathroom facilities.

  • Resistance to Excessive Hot Water: Its resistance to superhot water depends on the vulcanization system. With dithiodimorphine as the vulcanization system, it can work stably in hot water environments, making it suitable for hot water supply and hot spring facility applications.


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Electrical Insulation Performance


EPDM has excellent electrical insulation performance and corona resistance, with a volume resistivity of 10¹⁶Ω·cm and a breakdown voltage of 30 - 40mV/m. Even when immersed in water, its electrical properties change little. It is widely used in wire and cable sheaths and electrical equipment insulating parts.

Low Density and High Filling


With a low density of 0.86 - 0.87 g/cm³, EPDM can be filled with a large amount of oil and filler without significant performance reduction. This is useful in cost - sensitive rubber products like rubber floor tiles and low - end rubber hoses.

Good Elasticity


EPDM molecular chain has good flexibility and can maintain good elasticity at low temperature. It is second only to natural rubber and butadiene rubber in elasticity, making it suitable for applications in cold areas, such as wharf buffers and bridge shock pads.

Poor Adhesion


Due to the lack of active groups in its molecular structure, EPDM has poor self - adhesion and mutual viscosity. Special bonding processes and adhesives are required when bonding with other materials, but new techniques are gradually overcoming this problem.

Applications of EPDM

Automotive Industry


  • Car Seal Strip: EPDM is used in door, window, and trunk seal strips for its good sealing, weather, and elastic properties, providing a comfortable environment for passengers.

  • Weather Stripping: Installed around windshields and windows, it enhances vehicle tightness, blocks wind and rain, and reduces wind noise.

  • Radiator Hose: Its heat and chemical resistance make it ideal for radiator hoses, ensuring engine coolant circulation.

  • Fan Belts and Engine Covers: EPDM's strength, heat, and wear resistance meet the requirements of fan belts, and its oil, heat, and aging resistance are suitable for engine covers.

  • Tire Side: Used in tire sides for weather and ozone resistance, improving tire service life.

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Construction Field


  • Roof Waterproof Material: EPDM rubber waterproof coils are widely used for roof waterproofing, with longer service life and lower maintenance costs than traditional asphalt coils.

  • Waterproof Coil: Also used in building basements, pools, and tunnels for waterproofing, with good flexibility for complex structures.

  • Window Seals: EPDM window seals improve building energy - saving and living comfort, with good performance in different climates.

  • Plastic Roof Board: EPDM roof rubber sheets are lightweight, easy to install, and have good weather resistance, reducing building maintenance costs.

Power and Electronics


  • Wire and Cable Sheath: EPDM's electrical insulation, water vapor, and chemical resistance protect cable conductors, and its flexibility and wear resistance extend cable service life.


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  • Electrical Insulator: Its high electrical insulation and stability make it suitable for manufacturing electrical insulators in transformers, switches, etc., ensuring electrical system safety.

Other Fields


  • Rubber Hose and Tape: Used in food processing industry hoses for meeting hygiene standards and in conveyor belts for outdoor or humid environments.

  • Rubber Shoes: EPDM in rubber shoes provides good anti - slip, waterproof, and elastic properties for comfortable wear.

  • Rubber Floor Tile: Its low density and high fillability reduce costs, and its elasticity and wear resistance make it suitable for public places.

  • All kinds of Tape and Glue Boat: EPDM meets the requirements of special industrial and water operations, providing reliable material support.

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