🧩 EPDM – Ethylene Propylene Diene Monomer
(Saturated elastomeric material with excellent stability against UV, ozone, hot water, and steam. EPDM is the preferred material for exterior gaskets, bellows, and cooling hoses due to its long-term durability and elasticity. It is a thermoset rubber.)
🔹 What is EPDM
EPDM is a copolymer of ethylene, propylene, and a diene monomer. At ReplastMD, we handle EPDM as a high-performance weatherproofing material. Because of its saturated chain, it resists aging for 10–15 years in outdoor conditions. However, it is a thermoset (vulcanized) rubber, meaning it cannot be reshaped or welded by melting. For repairs, chemical bonding or cold vulcanization is the only way to restore integrity.
🔧 Composition & Properties
- Polymer Base: Ethylene + Propylene + ENB (diene).
- Density: 1.10 – 1.30 g/cm³.
- Hardness (Shore A): 40 – 90.
- Operating Range: –50 °C to +150 °C.
- Chemical Resistance: Excellent for water, steam, and glycol (antifreeze).
- Weakness: Petroleum-based oils and fuels will cause it to swell and degrade.
🚗 Where EPDM is used in the automotive industry
| Component | Example parts | Observations |
| Exterior Seals | Doors, windows, trunk | Resists UV, water, and ozone |
| Cooling Systems | Hoses, connectors, rings | Resists antifreeze and steam |
| Anti-vibration | Bellows, covers, protectors | Stable elasticity in hot/cold cycles |
| Static Gaskets | O-rings, profiles, sleeves | Durable, does not harden in the sun |
🔧 Welding Temperature and Methods
| Method | Compatibility | Observations |
| Hot Air | ❌ Cannot be welded | Thermoset – chars rather than flows |
| Heat Plate (Mirror) | ❌ Impossible | Thermally degrades under direct heat |
| Extrusion | ❌ N/A | Cannot be reshaped after vulcanization |
| Chemical Bonding | ✅ Recommended | Elastomeric/contact adhesives, special primers |
🔩 Compatibility (Bonding)
- ✅ Compatible: EPDM, NR, SBR, IR.
- ❌ Incompatible: PP, PE, PA, PC, PVC – does not adhere without surface treatment.
💡 ReplastMD Recommendation: EPDM does not melt. For repairs, use chemical bonding with cyanacrylate or rubber-based contact adhesives. For long sections, cold vulcanization (adhesive + pressure) is the professional choice.
🧠 How to Identify EPDM
- Elastic, soft, matte black texture; surface feels dry.
- Resistant to water, steam, and cold.
- ReplastMD practical test: Does not soften when heated. Burns with black smoke and a rubber scent.
- Common markings: >EPDM<, >KELTAN<, >VISTALON<.