PROEXPORT / TECHNICAL KNOWLEDGE
NBR vs EPDM: Elastomer Selection for Industrial Mediums
NBR and EPDM represent polar opposites in polymer chemistry. Selecting the wrong compound causes severe swelling, rapid softening, and delamination within 48 hours.
KNOWLEDGE & PRACTICE
Polymer Polarity and Engineering Comparison: NBR vs EPDM
| Technical Parameter / Resistance | NBR Rubber (Nitrile) | EPDM Rubber (Ethylene-Propylene) |
|---|---|---|
| Polymer Chemical Nature | Polar elastomer (nitrile butadiene copolymer) | Non-polar elastomer (ethylene propylene diene monomer) |
| Mineral Oils & Machine Greases | A — Excellent (zero swelling, stable hardness) | X — Severe failure (absorbs oil, swells up to 80%) |
| Ketones (MEK, Acetone, Cyclohexanone) | X — Severe failure (swells rapidly, degrades bond) | A — Excellent (chemically inert in ketone solvents) |
| Esters (Ethyl acetate, Butyl acetate) | X — Unsuitable (extreme volumetric swell) | B / A — Good to excellent compatibility |
| Aliphatic Solvents (Hexane, Heptane, Kerosene) | A — Highly resistant | X — Severe swelling and structural breakdown |
| UV-Curable Printing Inks & Monomers | X — Rapid degradation and hardening | A — Engineered choice for UV flexo and UV offset |
| Hot Water & Low-Pressure Steam | C — Limited to 80°C continuous | A — Exceptional stability up to 130°C continuous |
| Ozone, UV Weathering & Outdoor Life | C / X — Prone to surface ozone crazing | A — Complete immunity to atmospheric ozone cracking |
| Operating Temperature Range | -20°C to +100°C (peroxide: +120°C) | -40°C to +130°C (peroxide: +150°C) |
KNOWLEDGE & PRACTICE
The Trap of Washdown Solvents
The classical failure mechanism investigated by PROEXPORT failure analysts involves conflicting fluids:
A production line runs mineral-oil-based lubricants (ideal for NBR). However, night maintenance washes the equipment with acetone or ethyl acetate. The NBR roller swells overnight, and by morning the outer diameter has expanded by 1.5 mm, overloading bearings and cracking the covering.
Conversely, on packaging lines applying water-based or UV lacquers (ideal for EPDM), mechanics sometimes lubricate adjacent chain gears with mineral aerosol sprays, atomizing oil mist onto the EPDM roller and causing soft blister spots.
KNOWLEDGE & PRACTICE
Decision Tree: How PROEXPORT Selects NBR or EPDM
- Choose NBR: Roller contacts petroleum oils, grease, paraffinic solvents, animal fats, or diesel fuels.
- Choose EPDM: Roller operates in UV ink/coating units, contact with ketones/alcohols, steam lines, or outdoor weathering.
- Neither fits (dual exposure): PROEXPORT formulates hybrid CSM, fluorocarbon FKM (Viton®), or PTFE-sleeved composite coverings.
PROEXPORT / INDUSTRIAL ROLLERS
From technical drawing to line-ready solution.
Submit dimensions, photos, and operating conditions. We will determine the optimal manufacturing or reconditioning scope.