Ethylene Propylene Diene Rubber CAS 25038-36-2
Chelora Chemicals supplies dry and oil-extended EPDM grades to automotive sealing, roofing membrane, cable and technical rubber producers worldwide. Every consignment leaves with a batch-specific COA covering Mooney viscosity, ethylene and diene content, volatile matter and ash, the current SDS and full export documentation.
Also known as: EPDM · EPDM rubber · Ethylene propylene diene monomer rubber · EPT · Keltan type
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Price, lead time and a sample COA for Ethylene Propylene Diene Rubber, usually within one working day. We ship worldwide.
Request a Quote Email the DeskDocumentation
- Batch-specific COA (Mooney viscosity, ethylene content, diene content)
- Safety Data Sheet (SDS)
- Transport and export documents
- Third-party inspection on request
- Certificate of origin
What is Ethylene Propylene Diene Rubber?
EPDM is a terpolymer of ethylene, propylene and a small amount of a non-conjugated diene, usually ethylidene norbornene, which provides the unsaturation needed for sulphur vulcanisation.
Because the main chain is fully saturated, EPDM has outstanding resistance to ozone, weathering, UV and heat — properties no diene rubber can match.
Three parameters define a grade: ethylene content, which sets crystallinity and green strength; diene content, which sets cure rate and crosslink density; and Mooney viscosity, which sets processing behaviour.
Applications are dominated by automotive weatherseals, single-ply roofing membrane, cable insulation, hose and seals, plus a significant role as an impact modifier in polypropylene compounds.
Why EPDM specifically
- Saturated backbone. No double bonds in the main chain means ozone, UV and oxygen have nothing to attack, giving decades of outdoor life.
- Excellent heat resistance. Continuous service to about 130 °C, well above diene rubbers.
- Outstanding water and steam resistance. Which is why it dominates roofing membrane and cooling system hose.
- High filler and oil loading. Accepts very high loadings, which keeps compound cost low in sealing applications.
How Ethylene Propylene Diene Rubber is Manufactured
EPDM is made by solution or gas phase copolymerisation of ethylene and propylene with a diene termonomer.
- Monomer feed. Ethylene, propylene and ENB or another diene in the ratio the grade requires.
- Ziegler-Natta or metallocene catalysis. Vanadium-based Ziegler-Natta systems are traditional; metallocene catalysts give narrower distribution and better control.
- Solution polymerisation. Carried out in hexane, giving good control of composition and molecular weight.
- Gas phase polymerisation. An alternative route producing free-flowing granules directly, avoiding solvent.
- Oil extension. Paraffinic oil is added for the oil-extended grades, which are easier to mix at high Mooney.
- Finishing. Solution grades are stripped, dried and baled; gas phase grades ship as pellets or granules.
Typical Commercial Specification
Figures below are representative of a general-purpose EPDM. Each grade is defined by its ethylene, diene and Mooney combination — tell us the application and we will send the matching sheet.
| Parameter | Typical Value |
|---|---|
| Appearance | White to light tan bales, pellets or granules |
| Mooney viscosity ML (1+4) at 125 °C | 20 – 90 depending on grade |
| Ethylene content | 45 – 75% to grade |
| ENB diene content | 2 – 10% to grade |
| Volatile matter | 0.75% max |
| Ash content | 0.3% max |
| Oil content (extended grades) | Typically 50 to 100 phr |
| Antioxidant | To grade |
| Crystallinity | To grade, following ethylene content |
Physical & Chemical Properties
| Property | Value |
|---|---|
| Chemical formula | Terpolymer of ethylene, propylene and a non-conjugated diene |
| Appearance | White to light tan bales, pellets or granules |
| Density | About 0.86 g/cm³ — among the lightest elastomers |
| Glass transition temperature | About −50 to −60 °C |
| Service temperature | About −50 to 130 °C continuous |
| Ozone resistance | Outstanding, no antiozonant required |
| Water and steam resistance | Excellent |
| Oil resistance | Poor — swells badly in hydrocarbons |
| Electrical properties | Excellent insulation, used in cable |
| Filler acceptance | Very high; loadings of 200 phr and above are usual |
| Incompatibilities | Hydrocarbon oils and fuels, strong oxidisers |
Behaviour in the process
EPDM's saturated backbone gives it both its durability and its limitations:
- No ozone attack. The saturated main chain means outdoor service without antiozonant, unlike SBR, natural rubber or BR.
- Poor oil resistance. Swells badly in hydrocarbons; never use it where oil contact is expected.
- Poor adhesion to other rubbers. Bonding EPDM to diene rubbers or to metal needs specific adhesive systems.
- High filler acceptance. Takes very high black and oil loadings, which is central to its cost position in sealing.
EPDM Grades and Alternative Elastomers
EPDM is bought by composition, and the application determines where on the ethylene and diene scales the grade should sit.
| Material | Origin / type | When it is the right choice |
|---|---|---|
| High-ethylene EPDM | 60 to 75% ethylene | Extruded profiles and sponge where green strength matters |
| Medium-ethylene EPDM | 50 to 60% ethylene | General moulding and seals with good low-temperature flexibility |
| High-diene EPDM | 6 to 10% ENB | Fast cure and high crosslink density for continuous vulcanisation |
| Oil-extended EPDM | 50 to 100 phr oil | High molecular weight grades made mixable |
| Silicone rubber | Higher temperature range | Where service above 150 °C is required, at much higher cost |
Stated plainly: EPDM owns the outdoor and water-contact rubber market because nothing else combines weather resistance with that cost position. Where oil contact is involved, nitrile or a fluoroelastomer is the correct choice.
Industries We Supply Ethylene Propylene Diene Rubber To
EPDM serves automotive, construction, cable and technical rubber markets.
Where Ethylene Propylene Diene Rubber is Used
Automotive sealing and roofing membrane take the largest EPDM volumes, with cable and polypropylene modification behind them.
In automotive sealing
Weatherseal profiles are extruded and continuously vulcanised, which demands high green strength so the profile holds shape before cure, and fast cure so line speed can be maintained. That combination points to high-ethylene, high-diene, oil-extended grades, which is why automotive sealing grades are a distinct product family.
In roofing membrane
EPDM single-ply membrane has field service records measured in decades because the saturated backbone resists UV, ozone and water. Membrane grades emphasise low crystallinity for flexibility at low temperature and the cleanliness needed for consistent sheet, rather than the extrusion properties sealing grades require.
Need a specific grade, purity and packing format?
Tell us the grade, the ethylene, diene and Mooney combination your application requires, the packing format you can receive and the annual quantity. We will come back with a price, a lead time, a sample COA and the full documentation set.
Quality Control & Testing
Every lot is released against a batch-specific Certificate of Analysis with the grade's composition, so your compound laboratory can release against the actual material.
- Mooney viscosity — ML (1+4) at 125 °C, the primary processing indicator.
- Ethylene content — setting crystallinity, green strength and low-temperature behaviour.
- Diene content — setting cure rate and achievable crosslink density.
- Oil content — for extended grades, confirming the extension level.
- Volatile matter and ash — confirming drying and catalyst residues.
- Antioxidant type and level — to the grade specification.
Common Process Problems & Likely Causes
When EPDM causes trouble, it is usually composition drift, cure system or oil content. This table is the shortcut our technical desk works through before anyone opens a complaint file.
| Symptom | Likely cause | What to check |
|---|---|---|
| Extruded profile losing shape before cure | Ethylene content or Mooney lower than the previous grade | Ethylene content and Mooney figures |
| Cure rate slower than expected | Diene content below specification | ENB figure and cure system design |
| Low-temperature flexibility poor | Ethylene content too high, causing crystallinity | Ethylene content against the service requirement |
| Mixing viscosity unexpectedly high | Oil-extended grade substituted with a dry grade | Oil content and grade confirmation |
| Seal swelling in service | Oil or fuel contact — EPDM is the wrong elastomer | Application review; nitrile or FKM may be required |
| Poor adhesion to substrate | EPDM bonding requires specific adhesive systems | Adhesive selection and surface preparation |
Packaging, Storage & Shipping
- Standard packing. 25 to 35 kg bales in polyethylene film, or free-flowing pellets and granules for gas phase grades.
- Storage. Cool, dry, covered warehousing below 30 °C, away from direct sunlight.
- Stack height. Limit stacking; oil-extended bales deform under load in warm conditions.
- Segregation. Keep grades clearly separated; composition cannot be identified by appearance.
- Contamination. Keep away from oils and hydrocarbons, which the rubber absorbs readily.
- Pellet grades. Free-flowing granules simplify automatic feeding but need dry storage to avoid clumping.
- Shelf life. Typically 24 months in proper storage; EPDM is more stable than diene rubbers.
- Transport classification. Not classified as dangerous goods for transport.
Hazards & Safe Handling
EPDM is an inert polymer with no significant health hazard in normal handling. The practical concerns are manual handling of bales, mixing fume and compound ingredients.
- Inert in normal handling. Not classified as hazardous. Bales and pellets present no chemical risk in storage or transport.
- Manual handling. Bales are a significant ergonomic hazard; use mechanical handling where possible.
- Mixing fume. Internal mixer and mill operations generate rubber process fume; ventilation and extraction are required.
- Hot processing. Continuous vulcanisation lines, mills and presses present burn and entrapment hazards.
- Compound ingredients. Peroxides, sulphur systems, oils and fillers carry their own hazards; the compound SDS governs.
- Environment. Inert but persistent; contain waste and use established rubber recycling routes.
Regulatory & Compliance Notes
EPDM is unregulated for transport, with potable water and building standards applying by application. The notes below are orientation rather than legal advice.
- GHS classification. Not classified as hazardous.
- Transport. Not classified as dangerous goods. Standard packaged cargo documentation applies.
- Potable water approval. Seals and gaskets for drinking water require WRAS, KTW, NSF 61 or equivalent approval at compound level.
- Building standards. Roofing membrane must meet fire, wind uplift and durability standards in the relevant market.
- Automotive specifications. OEM material specifications and heat ageing requirements apply to sealing grades.
- REACH and inventories. Polymers are exempt from REACH registration, though monomers, oils and additives are not.
We Supply Ethylene Propylene Diene Rubber Worldwide
Chelora Chemicals is a supplier and export partner, not a single-plant trader. We ship Ethylene Propylene Diene Rubber from India and from partner sources to customers across Asia, Europe, the Middle East, Africa, and North and South America, handling the export documentation, transport paperwork and freight so the material arrives ready to use.
- Incoterms. EXW, FOB, CIF, CFR and DAP quoted to suit your purchasing terms and freight arrangements.
- Ports. Regular shipments through Nhava Sheva (JNPT) and Mundra, with other ports arranged where routing and cargo rules allow.
- Documentation. Commercial invoice, packing list, certificate of origin, COA, SDS and the transport declaration issued as a complete set.
- Flexible volumes. From a pallet of bales up to repeat bulk shipments on a supply contract.
- Supply continuity. Because we are independent of any one producer, a plant turnaround or a shipping disruption at one source does not have to become your stock-out.
Buying Ethylene Propylene Diene Rubber from Chelora
We are an independent sourcing and supply partner. For EPDM that means settling three things at enquiry: the ethylene and diene content your process and service conditions require, whether oil extension is needed, and whether potable water or OEM documentation applies.
- Documentation on every lot. Batch-specific COA (Mooney viscosity, ethylene content, diene content), plus SDS and the full transport paperwork.
- Analysis before commitment. Representative analysis shared ahead of a commercial order so your lab can qualify the material.
- Quantities. From a pallet of bales through to full bulk shipments on contract supply.
- Grade matching. Dry or oil-extended EPDM at the ethylene content, diene level and Mooney viscosity your application requires.
- Inspection. Independent third-party inspection available at loading when the contract requires it.
- Related products. Polypropylene, Nitrile Rubber, Butyl Rubber and other feedstocks alongside Ethylene Propylene Diene Rubber from one supplier.
How ordering works
- Send the enquiry. Product, grade or purity, quantity, destination port and the Incoterm you buy on. If you have a spec sheet, attach it — it saves a round trip.
- We quote. Price, lead time, packing format and a sample COA, normally within one working day.
- Qualify the supply. For first orders or critical applications, we share the analysis and handling documentation so your technical and safety teams can sign off before you commit.
- Confirm the order. Proforma invoice issued; payment terms agreed against the volume and the relationship.
- Allocation and QC. Material allocated and released against a batch-specific COA, with an independent inspection where the contract calls for it.
- Ship and document. Filled, labelled and loaded with the full export document set, and tracked through to arrival.
Ethylene Propylene Diene Rubber — Common Questions
The questions our technical desk is asked most often about Ethylene Propylene Diene Rubber. If yours isn't here, call or email and you will reach someone who knows the chemistry.
What is the CAS number of EPDM?
The CAS number for EPDM is 25038-36-2, and it is classified under HS code 4002.70. As a polymer it is exempt from REACH registration, though its monomers are not.
What is EPDM used for?
For automotive weatherseals and cooling system hose, single-ply roofing membrane, cable insulation, potable water seals and gaskets, and as an impact modifier in polypropylene and TPO compounds.
Do you supply EPDM worldwide?
Yes. Chelora Chemicals supplies and exports EPDM worldwide — across Asia Pacific, Europe, the Middle East, Africa and the Americas, as well as throughout India, in bales, pellets and granules.
Why is EPDM so resistant to weathering?
Because its main chain is fully saturated — the diene unsaturation sits on a pendant group, not in the backbone. Ozone, UV and oxygen have nothing to attack in the chain, which is why EPDM roofing lasts decades without antiozonant.
What do ethylene and diene content control?
Ethylene content sets crystallinity, green strength and low-temperature flexibility; diene content sets cure rate and crosslink density. Together with Mooney viscosity they define the grade, and Mooney alone tells you very little.
How is EPDM manufactured?
By copolymerising ethylene, propylene and a non-conjugated diene such as ENB over vanadium Ziegler-Natta or metallocene catalysts, in solution in hexane or in gas phase, with oil extension added for high molecular weight grades.
Can EPDM be used with oil or fuel?
No. EPDM swells badly in hydrocarbons. For oil contact, nitrile rubber is the standard choice, and fluoroelastomers for aggressive fuels and high temperature.
Is EPDM hazardous?
No. It is an inert polymer not classified as dangerous goods. The practical hazards are manual handling of bales, rubber process fume during mixing, and the hazards of the compounding ingredients.
Why are EPDM grades oil-extended?
Because high molecular weight grades give the best physical properties but are too viscous to mix. Adding 50 to 100 phr of paraffinic oil during manufacture makes them processable without losing the molecular weight benefit.
What temperature can EPDM withstand?
Continuous service to about 130 °C, with peroxide-cured compounds reaching higher. Low-temperature flexibility extends to about −50 °C, depending on ethylene content and crystallinity.
How should EPDM be stored?
In cool, dry, covered warehousing below 30 °C with limited stacking, since oil-extended bales deform under load. Keep grades clearly separated, as composition cannot be identified by appearance.
What packing sizes are available?
25 to 35 kg bales in polyethylene film, palletised or crated, and free-flowing pellets or granules for gas phase grades. Orders run from a pallet of bales up to full container loads.
Ready to source Ethylene Propylene Diene Rubber?
Send us your specification, grade and annual volume. You will get a price, a realistic lead time and a sample COA from someone who understands what the material has to do in your process — delivered anywhere in the world.