ECO CO (Epichlorohydrin homopolymer)
Grade
also Hydrin
Pick when the lowest gas/fuel permeability and best hydrocarbon resistance matter more than cold flexibility.
Values for the CO condition
Other ECO grades and fills
ECO is listed in 9 conditions; see the grade overview at ECO.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Shore A 50 | Soft diaphragms, bellows and low-clamp-force gaskets. | — | 9 | 400 | 12 Shore D |
Conductive / antistatic grade | Choose for fuel hose liners that must dissipate static charge per SAE J30/J2260 requirements. | — | 10 | 220 | 23 Shore D |
GECO / ETER | Use where sulfur or peroxide cure, lower compression set and the best low-temperature flexibility are required. | — | 11 | 280 | 18 Shore D |
Shore A 60 | Hose inner liners and flexible fuel-system components. | — | 11 | 320 | 16 Shore D |
Peroxide-cured GECO compound | Pick for static seals needing low compression set and no lead/thiourea cure residues. | — | 11 | 230 | 22 Shore D |
ECO-CODefault ECO | Standard choice for fuel and vacuum hose, diaphragms and seals needing oil resistance plus −40 °C flexibility. | — | 12 | 250 | 22 Shore D |
Shore A 70 | Default seal/O-ring and hose hardness; best balance of strength and set. | — | 12 | 250 | 22 Shore D |
COThis page Epichlorohydrin homopolymer | Pick when the lowest gas/fuel permeability and best hydrocarbon resistance matter more than cold flexibility. | — | 13 | 220 | 22 Shore D |
Shore A 80 | Higher-pressure seals, backup rings and stiff mount elements. | — | 13 | 180 | 30 Shore D |
What is ECO CO?
ECO CO is ECO in the CO grade — pick when the lowest gas/fuel permeability and best hydrocarbon resistance matter more than cold flexibility. ECO CO has a tensile strength of 13 MPa (1.89 ksi), weaker than 75% of polymer grades. Elongation at break is 220% and the elastic modulus is 0.01 GPa (0.001 Msi). ECO CO has a density of 1.41 g/cm³ (0.0509 lb/in³), heavier than 81% of polymer grades. Its glass-transition temperature is -22°C (-8 °F). ECO-CO is the default condition FabDigit quotes; CO is available on request or by drawing note.
Advantages
- Good UV / weathering resistance — 88/100, better than 90% of polymer grades
- Ductile — tolerates forming and impact — 220%, better than 77% of polymer grades
- Forms and bends easily — 80/100, better than 75% of polymer grades
Limitations
- Difficult to machine — 25/100, worse than 93% of polymer grades
- Absorbs moisture — dry before molding — 1.5%, worse than 91% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
- Low stiffness — 0.01 GPa (0.001 Msi), worse than 84% of polymer grades
- Difficult to weld — 10/100, worse than 82% of polymer grades
ECO CO properties
Typical room-temperature values for ECO CO; 20 are specific to this condition. Other listed values are ECO reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
ECO CO has a density of 1.41 g/cm³ (0.0509 lb/in³), heavier than 81% of polymer grades. Its glass-transition temperature is -22°C (-8 °F).
Mechanical8
ECO CO has a tensile strength of 13 MPa (1.89 ksi), weaker than 75% of polymer grades. Elongation at break is 220% and the elastic modulus is 0.01 GPa (0.001 Msi).
Thermal8
ECO CO is rated for continuous service to 130°C (266 °F). It conducts heat at 0.24 W/m·K (0.139 BTU/hr·ft·°F), better than 67% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical4
ECO CO is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (82/100), better than 56% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of ECO CO takes about 115 MJ of energy and emits 4.8 kg of CO₂ — more than 70% of polymer grades. Typical recycled content is 0%.
Manufacturability5
ECO CO's machinability is poor (25/100, worse than 93% of polymer grades); weldability not recommended (10/100); formability very good (80/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ECO CO
Is ECO easy to machine?
Cured ECO is best die-cut, water-jet or cryo-deflashed; grinding/turning needs sharp tools and freezing to avoid tearing and smearing.
Can ECO be welded?
Not weldable as a thermoset; joints are made by adhesive bonding (cyanoacrylate/epoxy on chlorinated-primer or plasma-treated surfaces) or by co-vulcanization during molding.
Can ECO be formed, bent or molded?
Mills and extrudes easily but is tacky and scorch-sensitive; compression/injection cure at 160–190 °C with an MgO-type acid acceptor, and post-cure 2–4 h at 150 °C for lowest compression set.
What surface finishes work on ECO?
Usually used as-molded in black; surfaces can be talc- or PTFE-dusted, plasma- or chlorine-treated for low friction, and adhesion to brass/steel inserts is achieved with standard rubber-to-metal bonding agents.
ECO chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| epichlorohydrin (ECH) unitschlorine-bearing repeat unit; ~30–38 wt% Cl in CO homopolymer | 55 – 75 | 68 |
| ethylene oxide (EO) unitsraises low-temperature flexibility, absent in CO homopolymer | 25 – 45 | 32 |
| allyl glycidyl ether (AGE)cure-site monomer, present only in GECO/ETER terpolymer | 0 – 8 | 0 |
| carbon black (N550/N774)phr in a typical 70 Shore A compound | 30 – 70 | 50 |
| plasticizer / process oil (ether-ester tphr | 0 – 20 | 8 |
| acid acceptor (MgO / hydrotalcite) + curphr; acid acceptor essential to trap evolved HCl | 3 – 10 | 6 |
ECO CO — frequently asked
What is ECO CO used for?
ECO CO is typically used for fuel hoses, vacuum hoses, automotive seals and low-temp gaskets. In short: fuel resistance to -40 °C; inherently antistatic elastomer; low permeability to fuels.
What is the tensile strength of ECO CO?
ECO CO has a typical tensile strength of 13 MPa (1.89 ksi) — weaker than 75% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is ECO CO easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of polymer grades). Cured ECO is best die-cut, water-jet or cryo-deflashed; grinding/turning needs sharp tools and freezing to avoid tearing and smearing.
Can ECO CO be welded?
Not readily — weldability is rated not recommended (10/100). Not weldable as a thermoset; joints are made by adhesive bonding (cyanoacrylate/epoxy on chlorinated-primer or plasma-treated surfaces) or by co-vulcanization during molding.
What surface finishes work on ECO CO?
Usually used as-molded in black; surfaces can be talc- or PTFE-dusted, plasma- or chlorine-treated for low friction, and adhesion to brass/steel inserts is achieved with standard rubber-to-metal bonding agents.
Can ECO CO be formed, bent or molded?
Mills and extrudes easily but is tacky and scorch-sensitive; compression/injection cure at 160–190 °C with an MgO-type acid acceptor, and post-cure 2–4 h at 150 °C for lowest compression set.
What is the maximum service temperature of ECO CO?
ECO CO is rated for continuous use to about 130°C (266 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Hydrin CO/ECO/ETER epichlorohydrin elastomer technical bulletins — Zeon Chemicals (2021)
- Engineered Materials Handbook Vol.2: Engineering Plastics / Rubber Products Manufacturing Technology — ASM International (1988)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications (type/class CH, CE) — ASTM (2020)
- ISO 1629 — Rubber and latices: nomenclature (CO, ECO, GECO) — ISO (2013)
- SAE J30 / SAE J2260 — Fuel and vapour hose requirements — SAE International (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.