SBR for Custom Molded Components — Properties, Applications & Specifications
Table of Contents
Styrene-Butadiene Rubber (SBR) achieves its abrasion resistance through a styrene-reinforced polymer matrix that distributes surface stress across a harder, more tightly cross-linked network than natural rubber — meaning the material resists micro-tearing under repeated sliding or impact contact rather than deforming and losing material. Without this mechanism, parts in high-wear sliding environments fail through progressive surface erosion that changes critical dimensional tolerances and shortens service life. Fenlora molds SBR compounds from 40–80 Shore A into floor-contact bumpers, conveyor rollers, wear pads, and abrasion liners for material handling, construction equipment, and industrial machinery.
Material Properties & Specifications
| Common names / abbreviations | Styrene-Butadiene Rubber (SBR) |
|---|---|
| Polymer structure / monomer system | Styrene and Butadiene copolymer |
| Tg (°C) / Brittle Point | -62 °C |
| Density (g/cm³) | 0.94 |
| Hardness range (Shore A/D) | 30 - 90 Shore A |
| Tensile strength (MPa) | 17.2 - 20.6 |
| Elongation at break (%) | 450 - 500 |
| 100% / 300% modulus (MPa) | 2.0 - 10.3 at 100% |
| Rebound / tanδ (temp + freq) | 20 - 90 % Rebound |
| Compression set (%) | 5 - 30 % |
| Continuous service temp (°C) | -40°C to 82°C |
| Environmental & Fluid Resistance | Ozone/UV: Poor | Pet/IRM 903: Poor |
| ASTM D2000 Callouts | ASTM D2000 M1AA 703 Z1 |
| Electrical properties | Vol Res: 5.0 - 8.4 x 10^8 ohm-cm |
| Thermal properties | Thermal Cond: 0.143 W/mK |
| Typical formulation ranges (phr) | Sulfur: 1.8 phr, Accelerator: 1.5 phr |
| Tear Resistance | Tier 2 - Limited |
| Abrasion Resistance | Tier 5 - Excellent |
| Gas Impermeability Resistance | Tier 2 - Limited |
| Oxygen Resistance | Tier 2 - Limited |
| Ozone Resistance | Tier 1 - Basic |
| Weathering Resistance | Tier 2 - Limited |
| Oil Resistance | Tier 1 - Basic |
| Acid Resistance | Tier 3 - Balanced |
| Alkaline Resistance | Tier 2 - Limited |
| Water Resistance | Tier 4 - Strong |
| Flame Resistance | Tier 2 - Limited |
When to Specify SBR
SBR is selected by engineers when abrasion resistance and cost efficiency are the primary design constraints — here’s where it earns its place and where it doesn’t.
| Use SBR when… | Avoid SBR when… |
|---|---|
| Surface wear resistance is the primary failure mode and the contact medium is dry or water-wet | Hydrocarbon oils, fuels, or solvents are present — SBR swells significantly in petroleum-based fluids |
| Operating temperature stays within –40°F to +180°F (–40°C to +82°C) continuous | Continuous temperatures exceed 212°F (100°C) — heat aging causes hardening and crack propagation |
| Budget is a primary constraint and performance requirements match natural rubber | Ozone or UV exposure is prolonged — SBR lacks inherent ozone resistance and will surface-crack |
| Dynamic load is compressive or impact-type rather than tensile-flex cycling | The application requires low compression set — SBR performs poorly in long-term static sealing roles |
| The application involves repeated abrasive sliding contact against hard surfaces (concrete, steel, aggregate) | Electrical insulation is required — SBR’s dielectric properties are inconsistent without specific compounding |
SBR’s abrasion advantage comes from the styrene content (typically 23–25% in general-purpose grades) stiffening the polymer backbone enough to resist the adhesive and abrasive wear mechanisms that dominate in sliding contact. In DIN 53516 abrasion testing, properly compounded SBR can achieve volume loss figures comparable to or better than natural rubber, and at a lower compound cost per unit volume — which is why it dominates flooring underlays, conveyor components, and dock bumpers where wear depth directly correlates to replacement intervals.
Custom Parts We Make in SBR
Fenlora manufactures the following compression-molded, transfer-molded, and extruded SBR components to customer drawings or functional specifications.
→ Dock bumpers and impact pads — SBR’s ability to absorb repeated compressive impact without permanent deformation makes it the standard compound for loading dock face pads and truck bumpers; hardness is typically specified at 55–65 Shore A to balance energy absorption with rebound.
→ Conveyor belt rollers and lagging — In aggregate, mining, and bulk material handling, SBR lagging on steel rollers resists the continuous abrasive sliding of belt-on-roller contact far better than natural rubber at comparable cost.
→ Wear strips and abrasion liners — Used in chutes, hoppers, and guide channels where bulk solids or abrasive slurries contact stationary surfaces; SBR at 60–70 Shore A extends replacement intervals versus softer compounds.
→ Floor grommets and cable pass-throughs — In industrial and commercial flooring applications where pedestrian or equipment traffic creates abrasive surface contact, SBR grommets maintain dimensional integrity longer than NR equivalents.
→ Extruded edge trim and protective profiles — SBR extrusions protect metal edges and structural components in construction equipment and vehicle body applications from impact and abrasive contact.
If your drawing specifies SBR or you’re working from functional requirements around wear resistance and load, contact our engineering team to discuss compound selection and hardness range: contact us.
Industries That Use SBR
Automotive(Non-Sealing Applications)
SBR appears in brake shoe bondings, body isolation pads, and flooring underlays in automotive manufacturing where contact abrasion is the dominant wear mode and petroleum fluid contact is minimal or absent. The cost advantage over specialty elastomers is significant at automotive production volumes. (Link to automotive industry)
Material Handling & Bulk Conveying
SBR is specified for conveyor rollers, impact saddles, and chute liners in aggregate, sand, and recycling operations where continuous abrasive contact destroys softer elastomers within weeks. The hardened polymer matrix resists the micro-cutting mechanism that degrades natural rubber under high-silica particle loads, extending service intervals and reducing replacement costs at scale.
General Industrial Machinery
Anti-vibration mounts, machinery feet, and protective bumpers across press operations, packaging lines, and fabrication facilities use SBR at 50–65 Shore A to combine vibration damping with wear resistance against concrete and steel floor surfaces. In dry environments without chemical exposure, SBR delivers NR-comparable mechanical performance at lower compound cost.
Construction Equipment
Dock bumpers, mud flap mounts, and suspension wear pads in construction and heavy equipment use SBR because the operating environment combines mechanical abrasion with water exposure — conditions where SBR’s resistance to wet abrasion and hydrolysis outperforms alternatives. Compressors, concrete mixers, and material lifts all generate repetitive impact loads that SBR handles without the dimensional fatigue that shortens NR component life.
Compare Materials
SBR is the right choice in dry abrasive environments, but several specific application conditions call for a different elastomer — use this table to check your requirements before specifying.
| If your application involves… | Consider instead |
|---|---|
| Outdoor UV or ozone weathering | EPDM |
| Budget-sensitive oil resistance only | Nitrile (NBR) |
| Continuous temps above 150°C | Silicone (VMQ) |
| High dynamic flex and tear resistance | Natural Rubber (NR) |
| High abrasion and mechanical wear | Polyurethane (AU/EU) |
| Moderate oil + weather resistance | Neoprene (CR) |
| Air/gas impermeability | Butyl (IIR) |
| Extreme chemical resistance | Viton (FKM) |
Not sure which material fits your application? Send us your requirements and we’ll recommend the right compound.