Bromobutyl Rubber (BIIR) – Airtight, Heat and Chemical Resistant Halobutyl Elastomer
Bromobutyl Rubber (BIIR) is a halogenated derivative of Butyl Rubber (IIR) produced by brominating isobutylene-isoprene copolymer. The addition of bromine atoms to the polymer backbone increases the reactivity and crosslinking versatility of the rubber, enabling faster curing, stronger interfacial bonding, and enhanced heat and chemical resistance compared to non-halogenated IIR.
At Eutsler Technical Products, our BIIR compounds are engineered for applications requiring airtight sealing, chemical resistance, and heat stability under dynamic or static conditions. BIIR maintains the low gas permeability and vibration damping of traditional Butyl Rubber while offering improved adhesion, faster cure kinetics, and broader compatibility with curing systems — including sulfur, peroxide, and resin cures.
Performance Advantages
- Outstanding gas and vapor impermeability maintains air retention and vacuum integrity over extended service life.
- Improved cure reactivity and bonding halogenation enables faster vulcanization and strong adhesion to metals and other elastomers.
- Enhanced heat and chemical resistance performs at higher temperatures and in more aggressive environments than standard IIR.
- Excellent ozone, oxidation, and weathering resistance is stable against long-term UV and atmospheric degradation.
- Low compression set maintains sealing load and resilience under sustained stress.
- Superior vibration damping and sound absorption excellent for shock and acoustic isolation.
- Good resistance to polar fluids and aqueous chemicals functions in glycol-based fluids, acids, and alkaline media.
- Broad compounding versatility compatible with co-curing in blends with NR, BR, CR, and EPDM for hybrid performance.
Applications
Eutsler’s custom BIIR compounds are used where airtightness, bonding performance, and heat resistance are required beyond the limits of conventional IIR.
Typical applications include:
- Tire inner liners and bladders
- Diaphragms, accumulators, and bladders
- Vacuum and pressure seals
- Pharmaceutical and food-processing seals (low-permeation grades)
- Vibration isolators and acoustic dampers
- Engine mounts and air suspension components
- Rubber-to-metal bonded seals and isolators
- Valve and pump diaphragms in chemical or polar-fluid systems
BIIR’s unique combination of gas impermeability, adhesion, and chemical stability makes it ideal for pressure containment, vibration control, and chemical sealing applications.
Superior Material Performance
Eutsler’s BIIR compounds deliver:
- Tensile strength: 1,000 – 2,000 psi with elongation up to 500%
- Excellent heat resistance up to 325 °F (163 °C) intermittent
- Outstanding air impermeability — among the lowest gas transmission of any rubber
- Enhanced cure compatibility for bonding and co-vulcanization applications
- Improved dynamic fatigue resistance and long-term elasticity
- Excellent damping and shock absorption
- Good electrical insulation with low dielectric constant
Note: BIIR is not suitable for continuous contact with petroleum-based oils or fuels. For hydrocarbon or aromatic solvent resistance, NBR, HNBR, or FKM are better alternatives.
General Characteristics of Bromobutyl Rubber (BIIR)
| Property | Typical Range / Rating | Comments |
|---|---|---|
| Durometer Range (Shore A) | 40 – 90 | Custom hardness range available |
| Tensile Strength (psi) | 1,000 – 2,000 | Strong, flexible mechanical performance |
| Elongation at Break (%) | 300 – 500 | Excellent elasticity |
| Compression Set | Good – Excellent | Retains sealing force after heat and compression |
| Resilience / Rebound | Fair – Good | High damping and energy absorption |
| Abrasion Resistance | Fair – Good | Suitable for static or low-motion sealing |
| Tear Resistance | Good | Strong interfacial bonding after cure |
| Oil Resistance | Poor | Not for petroleum or hydrocarbon fuels |
| Solvent Resistance | Good (polar solvents) | Resistant to water, acids, and glycols |
| Gas Permeability | Outstanding (very low) | Excellent air/vacuum retention |
| Low-Temperature Usage | –40 °F (–40 °C) | Flexible at low temperature |
| High-Temperature Usage | +300 °F (150 °C) continuous; +325 °F (163 °C) intermittent | High heat resistance for IIR-class elastomer |
| Weather / Ozone / Sunlight Resistance | Excellent | Long-term environmental durability |
| Adhesion to Metals | Excellent | Outstanding co-vulcanization capability |
| Chemical Resistance | Excellent (polar systems) | Resists acids, alkalies, and aqueous solutions |
| Damping / Acoustic Isolation | Excellent | Ideal for vibration and noise control |
Work with Eutsler for Precision-Molded BIIR Components
With over 60 years of experience in elastomer compounding and molding, Eutsler Technical Products specializes in custom BIIR components optimized for airtightness, vibration control, and chemical resistance.
Our engineering team collaborates with customers to define cure system, hardness, and filler package tailored for the intended environment — from vacuum and pressure seals to bonded isolation assemblies.
As an ISO 9001:2015-certified manufacturer, we ensure strict quality control, consistency, and material traceability from prototype through production.
Request a quote today to develop high-performance BIIR parts built for long service life and superior environmental sealing.
Summary
Bromobutyl Rubber (BIIR) provides advanced airtightness, bonding capability, and chemical resistance, making it a superior material for pressure systems, isolation mounts, and chemical sealing applications requiring durability and long-term environmental stability.
- Chemical Family:Brominated Isobutylene-Isoprene Copolymer (Halobutyl Rubber)
- Service Temperature Range:–40 °F to +300 °F (–40 °C to +150 °C)
- Distinguishing Features:Excellent air impermeability with enhanced cure and adhesion characteristics
- Key Advantages:
- Extremely low gas permeability
- Improved bonding and co-vulcanization properties
- Excellent chemical, ozone, and weather resistance
- Strong damping and vibration absorption
- Good heat and aging stability
- Limitations:
- Poor oil and fuel resistance
- Moderate abrasion and tear resistance
Why Choose Eutsler Technical Products?
R&D
Experienced staff develop high performance and long life parts
Material Selection
Over 300 compounds or custom elastomeric compounds available
Mold Design
Custom molds are designed ensuring tolerances are met
Manufacturing
Molding, extrusion and die cutting services to build your part
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