EPDM Rubber
The EPDM synthetic rubber supplied by Chelora Chemicals — a fully saturated-backbone elastomer prized for weathering and heat resistance — exported from Indonesia as raw bale with full batch documentation on every shipment.
What EPDM Rubber is, and why buyers source it
A working overview of the elastomer's fully saturated backbone, how a small amount of diene monomer enables vulcanisation, and the grades Chelora Chemicals keeps in regular supply.
EPDM is a terpolymer built from ethylene and propylene, the same two olefins that feed the polyolefin plastics industry, plus a small proportion of a third, diene monomer (most commonly ethylidene norbornene, ENB) whose purpose is entirely different from the other two: it introduces an unsaturated side group, pendant from the main chain rather than along the backbone itself, that provides the only reactive site needed for sulphur vulcanisation. The main ethylene-propylene backbone itself is fully saturated, with no double bonds at all, which is the direct structural reason EPDM resists ozone, UV and weathering degradation far better than the diene-based rubbers (natural rubber, SBR, nitrile) whose backbones carry unsaturation throughout the chain.
As supplied, raw EPDM is a pale tan to grey, flexible solid, shipped in standard bales for compounding. Ethylene content governs the polymer's crystallinity and therefore its green strength and processing behaviour, while diene content governs cure rate and crosslink density achievable during vulcanisation — between them, these two ratios define the bulk of the grade differentiation across the EPDM product range.
Where it fits in the value chain
EPDM's outstanding weathering, ozone and heat-ageing resistance make it the dominant rubber for products that must survive years of continuous outdoor exposure: automotive weatherstripping and seals, radiator and coolant hoses, roofing membrane, and glazing seals for building facades. Because its backbone can also absorb large amounts of mineral oil and filler without a proportional loss of properties, it is often supplied in an oil-extended form that lowers compounded cost while retaining good performance, and it is also widely blended with polypropylene (thermoplastic olefin, or TPO/TPV) for bumper fascias and other semi-rigid automotive exterior parts.
Grades we supply
Chelora Chemicals offers EPDM across general-purpose, oil-extended and high-diene (fast-curing) grades, differentiated by ethylene content, diene content and Mooney viscosity. Each grade is supplied with a batch-wise certificate of analysis covering Mooney viscosity, ethylene content and diene content.
How EPDM Rubber is produced
An overview of the production route for orientation purposes. Our manufacturing partners' own process parameters and in-process controls are proprietary and are not disclosed beyond what is needed to interpret the certificate of analysis.
EPDM is produced by solution or suspension copolymerisation of ethylene, propylene and a diene termonomer, most commonly ethylidene norbornene (ENB), under a Ziegler-Natta or metallocene (vanadium- or more recently constrained-geometry-catalyst) coordination catalyst system. The catalyst incorporates the three monomers into a single growing chain at controlled, independently adjustable ratios, which is what gives producers the freedom to tune ethylene content (crystallinity, processing) and diene content (cure rate) largely independently of one another within a single production platform.
After polymerisation, the rubber is coagulated from solution (or, for the suspension route, recovered directly), washed, dried and baled, with oil-extension, where specified, carried out by blending a defined quantity of process oil into the polymer during the finishing stage rather than left to the compounder to add separately.
Industries and processes that use it
EPDM is consumed across automotive sealing, roofing membrane, hose and building-glazing applications. The fields below account for most of the demand we see through our export desk.
Automotive Weatherstripping & Seals
Extruded and moulded into door, window and trunk seals exploiting EPDM's resistance to ozone and weathering across the vehicle's outdoor service life.
Radiator & Coolant Hose
Compounded and extruded into coolant and heater hose, where heat resistance and resistance to glycol-based coolant chemistry are both required.
Roofing Membrane
Calendered into large-format single-ply roofing membrane sheet, one of the most widely used flat-roofing materials, valued for decades-long outdoor weathering performance.
Building Glazing & Gaskets
Extruded into glazing seals and gaskets for curtain-wall and window systems exposed to continuous UV and weathering.
How the rubber is typically compounded forward
The saturated backbone and the pendant diene's reactivity govern almost all of EPDM's further compounding behaviour. The categories below account for most of the ways it is converted into a finished rubber product.
Compounding
The raw polymer is mixed with carbon black or mineral filler, process oil, and a curing system, typically sulphur-based or peroxide-based depending on the required heat resistance of the finished part.
Sulphur Vulcanisation
At the diene's pendant unsaturation, sulphur crosslinks form between adjacent chains during the cure cycle, converting the soft, uncured compound into an elastic, dimensionally stable rubber part.
Peroxide Vulcanisation
An alternative cure system used where higher continuous-service heat resistance is needed than a sulphur cure provides, crosslinking directly at carbon-carbon sites along the chain rather than through the diene group.
Extrusion & Moulding
Compounded, uncured rubber is extruded into profile (seals, hose) or moulded into shaped parts, then cured in-line or in a separate autoclave or press cycle.
EPDM against its feedstock olefins we supply
Buyers sourcing EPDM rubber sometimes also need the olefin monomers it is built from, or a related synthetic rubber for a different seal or hose grade. A quick reference to what else is on our regular supply list.
| Product | CAS Number | Category | Notes |
|---|---|---|---|
| EPDM Rubber | 25038-36-2 | Ethylene-propylene-diene terpolymer | The product on this page — a weathering- and heat-resistant synthetic elastomer. |
| Ethylene | 74-85-1 | Olefin monomer | One of the two principal monomers this elastomer's saturated backbone is built from — see its product page. |
| Propylene | 115-07-1 | Olefin monomer | The other principal monomer this elastomer's saturated backbone is built from — see its product page. |
| Nitrile Rubber | 9003-18-3 | Butadiene-acrylonitrile copolymer | A related synthetic rubber chosen instead where oil resistance, rather than weathering resistance, is the priority — see its product page. |
Exact physical constants and processing specifications are confirmed per batch on the certificate of analysis — treat the notes above as a sourcing guide, not a specification sheet, for products other than EPDM Rubber.
Safety classification at a glance
Based on GHS classification as commonly listed for this substance. This is a summary for orientation only — always work from the current safety data sheet supplied with your specific batch.
Not classified as hazardous under GHS in raw bale form.
Combustible; store away from open flame and other ignition sources.
Compounding and curing operations generate process fumes and particulate; ensure adequate ventilation and extraction at the mixing mill or press.
Oil-extended grades contain a mineral process oil; handle per standard oil-handling precautions during compounding.
Standard gloves and eye protection are sufficient for routine handling of the raw bale.
Sulphur- and peroxide-cure systems can generate characteristic odours and fumes during vulcanisation; ensure extraction at the cure press.
Not classified; refer to the batch MSDS for grade-specific guidance.
This product has a low hazard profile in its raw bale form and is not classified as hazardous under GHS. The main precautions concern standard combustible-solid storage practice and adequate ventilation during compounding and curing, where process fumes and odours from the curing system (sulphur or peroxide) are generated. Full first-aid, storage, spill and PPE guidance is in the MSDS issued with every shipment, and should be read in full before this material is handled.
Keeping it on spec between delivery and use
General storage guidance for this grade. Site-specific storage rules, segregation requirements and re-test intervals should follow your own EHS procedures and the MSDS issued with your batch.
Store in a cool, dry area out of direct sunlight, since raw uncured rubber is itself subject to some ageing in storage, though far less than diene-backbone rubbers given EPDM's inherent ozone resistance. Keep bales clear of ozone-generating equipment (such as electrical arc sources) and strong oxidising agents. Re-check Mooney viscosity on a batch held past its retest date before use, as some viscosity drift can occur over extended storage.
How it ships from Indonesia
Standard packing and export terms for this product. Confirm exact figures against your order — they vary slightly by destination and quantity.
What travels with every batch
Specification is agreed before the purchase order, not discovered on arrival. Every shipment of EPDM Rubber leaves with a documented, checkable paper trail.
Certificate of Analysis
Batch-wise assay, colour and key physical constants, issued against the agreed specification so your QC team can check it, not just file it.
Safety Data Sheet
GHS-format SDS in English covering hazard classification, handling, storage, first-aid and spill response for the exact grade shipped.
Technical Data Sheet
Reference physical and chemical properties, recommended storage and typical applications, for internal circulation to your process or R&D teams.
Certificate of Origin
Confirms Indonesian origin for customs clearance and any preferential-duty claim at your destination port.
Dangerous Goods Declaration
UN packing group, classification and shipper's declaration prepared ahead of loading so documentation never holds up customs.
Third-Party Inspection
Independent pre-shipment inspection and re-sampling can be arranged on request, at your cost, for buyers who require it as a matter of policy.
Frequently asked questions
What buyers most often ask our sales desk about this grade.
01What is EPDM Rubber used for?+
02What does EPDM stand for and what is it made from?+
03How is EPDM Rubber produced?+
04What grades does Chelora Chemicals supply?+
05Is EPDM Rubber hazardous?+
06Why does EPDM resist weathering so much better than other rubbers?+
07What packing options are available?+
08How long does delivery take?+
09Can I get a sample before placing a bulk order?+
10Do you supply the ethylene and propylene feedstocks as well?+
Need EPDM Rubber on spec, on time?
Send us your required ethylene/diene ratio, Mooney viscosity, oil-extension requirement and destination port. Our desk quotes most enquiries within one working day.