Comparison of Rubber Bush Materials
Selecting the right material for your rubber bush is critical for performance and longevity. Below is a detailed comparison of all materials we use at Vertex Rubber, with their properties, applications, and limitations.
1. Nitrile Rubber (NBR) — Oil & Fuel Resistant
Chemical Composition: Acrylonitrile-butadiene rubber — the most widely used elastomer for oil-resistant applications.
- Best Use Cases: Automotive suspension bushes, engine mounts, hydraulic equipment, oil pump seals, fuel system components
- Temperature Range: -30°C to +120°C (peak +140°C intermittent)
- Chemical Resistance: Excellent resistance to oils, fuels, greases, and hydraulic fluids. Poor resistance to ozone, sunlight, and polar solvents.
- Durability: Good abrasion resistance, moderate tensile strength (12-15 MPa), excellent compression set resistance
- Price Range: ₹ — Most cost-effective option for oil-resistant applications
- When NOT to use: Outdoor/UV-exposed applications, high-temperature environments above 140°C, contact with brake fluid or ketones
2. Polyurethane (PU) — High Wear Resistance
Chemical Composition: Polyurethane elastomer — not a true rubber but offers superior mechanical properties.
- Best Use Cases: Heavy machinery mounts, mining equipment, suspension bushes for off-road vehicles, industrial rollers, press tool mounts
- Temperature Range: -30°C to +100°C
- Chemical Resistance: Good resistance to oils, greases, and water. Poor resistance to acids, alkalis, and polar solvents.
- Durability: Exceptional abrasion resistance (3-5x better than rubber), very high load-bearing capacity, excellent tear strength
- Price Range: $$$ — Higher cost but longer service life in demanding applications
- When NOT to use: High-temperature applications above 100°C, continuous exposure to strong acids or alkalis
3. EPDM Rubber — Weather & Ozone Resistant
Chemical Composition: Ethylene propylene diene monomer — the preferred material for outdoor applications.
- Best Use Cases: Railway track pads, bridge bearings, outdoor structural mounts, water pump seals, HVAC system mounts
- Temperature Range: -40°C to +120°C (peak +150°C intermittent)
- Chemical Resistance: Excellent resistance to ozone, UV, weathering, water, steam, and diluted acids. Poor resistance to oils and fuels.
- Durability: Excellent weather resistance, good flexibility at low temperatures, moderate tensile strength
- Price Range: $$ — Moderate cost, excellent value for outdoor use
- When NOT to use: Oil/fuel contact applications, food contact (unless special grade), hydrocarbon environments
4. Natural Rubber (NR) — High Flexibility & Strength
Chemical Composition: Polyisoprene — natural latex-based rubber with exceptional mechanical properties.
- Best Use Cases: Heavy-duty vibration dampers, seismic isolation bearings, rail pads, large industrial mounts, shock absorbers
- Temperature Range: -50°C to +80°C (peak +100°C intermittent)
- Chemical Resistance: Poor resistance to oils, fuels, and solvents. Excellent resistance to water and diluted acids.
- Durability: Highest tensile strength (20-30 MPa), excellent elasticity, superior tear resistance, good abrasion resistance
- Price Range: ₹ — Cost-effective for general-purpose high-performance applications
- When NOT to use: Oil/fuel contact, high-temperature applications, outdoor/ozone exposure (unless compounded with antiozonants)
5. Neoprene (CR) — General Purpose with Flame Resistance
Chemical Composition: Chloroprene rubber — a versatile general-purpose elastomer with inherent flame resistance.
- Best Use Cases: Marine engine mounts, transformer mounts, electrical equipment, general industrial mounts, conveyor system rollers
- Temperature Range: -30°C to +100°C (peak +120°C intermittent)
- Chemical Resistance: Good resistance to oils, greases, and chemicals. Self-extinguishing (flame resistant). Moderate ozone resistance.
- Durability: Good all-round mechanical properties, moderate tensile strength, good weather resistance
- Price Range: $$ — Moderate cost, good value for general-purpose applications
- When NOT to use: High-temperature applications, strong acid environments, applications requiring extreme oil resistance
How Cheap Manufacturers Cut Corners
In India's rubber bush market, some manufacturers compromise quality to offer lower prices. Here's how:
- Using recycled fillers: Replacing virgin rubber compound with reprocessed rubber and cheap fillers like calcium carbonate (chalk). Result: poor tensile strength, rapid ageing, premature failure.
- Wrong curing agents: Using incorrect or insufficient curing agents to reduce costs. Result: under-cured bushes with poor compression set (permanent deformation).
- Skipping quality tests: Not performing hardness, tensile, compression set, or bond strength tests. Result: inconsistent quality batch to batch.
- Thinner cross-sections: Manufacturing with thinner rubber sections than specified to save material. Result: reduced load capacity and early failure.
- Poor bonding: Inadequate rubber-to-metal bonding. Result: bond failure under load, bush separates from sleeve.
At Vertex Rubber, we never compromise on material quality. Every batch is tested, every bush is inspected, and every shipment meets ASTM D2000 standards.