BIIR INNERLINER
Grade
Calendered sheet compound optimized for minimum air permeability and co-vulcanization/adhesion to carcass skim stock.
Values for the INNERLINER condition
Other BIIR grades and fills
BIIR is listed in 8 conditions; see the grade overview at BIIR.
Compare all 8 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Mineral (clay/talc/CaCO3) filled, non-black compound | Use where colour, electrical insulation or non-marking contact surfaces are needed instead of carbon black reinforcement. | — | 7 | 450 | 15 Shore D |
Shore A 40 | Pick for vibration isolators, soft gaskets and acoustic damping where maximum hysteresis and conformability are wanted. | — | 8 | 700 | 8 Shore D |
Shore A 50 | Balance of sealing conformability and strength for low-pressure gaskets and bladders. | — | 9 | 600 | 11 Shore D |
INNERLINERThis page Tire innerliner compound (BIIR/NR blend, high air retention) | Calendered sheet compound optimized for minimum air permeability and co-vulcanization/adhesion to carcass skim stock. | — | 10 | 650 | 13 Shore D |
CB-A60Default Carbon-black filled, Shore A 60 | Default general-purpose BIIR compound (N550/N660 black, ZnO/sulfur cure) for seals, diaphragms and damping parts. | — | 11 | 500 | 15 Shore D |
Resin-cured (phenolic resin) heat-resistant compound | Phenolic-resin cure system for tire curing bladders and steam service — best heat ageing and lowest compression set. | — | 11 | 500 | 14 Shore D |
Shore A 70 | Choose for higher-pressure seals, hose covers and parts needing extrusion resistance. | — | 12 | 420 | 22 Shore D |
Shore A 80 | For rigid mounts, backup rings and parts requiring stiffness and low deflection under load. | — | 13 | 300 | 30 Shore D |
What is BIIR INNERLINER?
BIIR INNERLINER is BIIR in the INNERLINER grade — calendered sheet compound optimized for minimum air permeability and co-vulcanization/adhesion to carcass skim stock. BIIR INNERLINER has a tensile strength of 10 MPa (1.45 ksi), weaker than 79% of polymer grades. Elongation at break is 650% and the elastic modulus is 0 GPa (5.08×10⁻⁴ Msi). BIIR INNERLINER has a density of 1.12 g/cm³ (0.0405 lb/in³), lighter than 64% of polymer grades. Its glass-transition temperature is -60°C (-76 °F). CB-A60 is the default condition FabDigit quotes; INNERLINER is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 650%, better than 94% of polymer grades
- Forms and bends easily — 90/100, better than 91% of polymer grades
- Good UV / weathering resistance — 85/100, better than 88% of polymer grades
Limitations
- Low stiffness — 0 GPa (5.08×10⁻⁴ Msi), worse than 92% of polymer grades
- Difficult to machine — 28/100, worse than 90% of polymer grades
- High mold shrinkage — 2.2%, worse than 87% of polymer grades
BIIR INNERLINER properties
Typical room-temperature values for BIIR INNERLINER; 18 are specific to this condition. Other listed values are BIIR reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
BIIR INNERLINER has a density of 1.12 g/cm³ (0.0405 lb/in³), lighter than 64% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
Mechanical11
BIIR INNERLINER has a tensile strength of 10 MPa (1.45 ksi), weaker than 79% of polymer grades. Elongation at break is 650% and the elastic modulus is 0 GPa (5.08×10⁻⁴ Msi).
Thermal8
BIIR INNERLINER is rated for continuous service to 120°C (248 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical5
BIIR INNERLINER is an electrical insulator with a dielectric strength of 25 kV/mm (635 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.
Sustainability4
Producing a kilogram of BIIR INNERLINER takes about 105 MJ of energy and emits 3.6 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability5
BIIR INNERLINER's machinability is poor (28/100, worse than 90% of polymer grades); weldability fair (35/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BIIR INNERLINER
Is BIIR easy to machine?
Only die cutting, waterjet or cryogenic deflashing are practical; vulcanized BIIR is gummy and heat-sensitive for conventional machining.
Can BIIR be welded?
Not weldable — parts are joined by uncured splicing then co-vulcanization, or by adhesive bonding after chlorinated/plasma surface activation.
Can BIIR be formed, bent or molded?
Mix cool (drop <115 °C) to avoid scorch, then calender/extrude and cure 8–20 min at 160–180 °C; avoid contamination with sulfur-rich stocks and use ZnO-based halobutyl cure systems.
What surface finishes work on BIIR?
Surfaces are naturally low-friction and non-paintable; use chlorination, halogenation or plasma treatment before painting/bonding, and post-cure or wash for pharma/food closures.
BIIR 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 |
|---|---|---|
| isoprene (repeat unit)unsaturation site for halogenation/cure | 1.5 – 2.5 | 2 |
| Brbound bromine on polymer, e.g. Bromobutyl 2222 ≈ 2.0 % | 1.6 – 2.3 | 2 |
| carbon black (N550/N660)phr in default vulcanizate, not wt% of polymer | 30 – 60 | 50 |
| ZnO / stearic acid / cure packagephr; ZnO-activated halobutyl cure | 1 – 5 | 3 |
| process oil / tackifierphr, paraffinic | 5 – 20 | 10 |
| isobutylene (repeat unit)polymer backbone | ≥ 96 (balance) | — |
BIIR INNERLINER — frequently asked
What is BIIR INNERLINER used for?
BIIR INNERLINER is typically used for tire innerliners, pharmaceutical closures, curing bladders and sealants. In short: fastest-curing halobutyl; best butyl air retention; pharma closure grade.
What is the tensile strength of BIIR INNERLINER?
BIIR INNERLINER has a typical tensile strength of 10 MPa (1.45 ksi) — weaker than 79% of polymer grades. Strength varies by condition: see the 8 listed tempers.
Is BIIR INNERLINER easy to machine?
Not especially — machinability is rated poor (28/100, worse than 90% of polymer grades). Only die cutting, waterjet or cryogenic deflashing are practical; vulcanized BIIR is gummy and heat-sensitive for conventional machining.
Can BIIR INNERLINER be welded?
With care — weldability is rated fair (35/100). Not weldable — parts are joined by uncured splicing then co-vulcanization, or by adhesive bonding after chlorinated/plasma surface activation.
What surface finishes work on BIIR INNERLINER?
Surfaces are naturally low-friction and non-paintable; use chlorination, halogenation or plasma treatment before painting/bonding, and post-cure or wash for pharma/food closures.
Can BIIR INNERLINER be formed, bent or molded?
Mix cool (drop <115 °C) to avoid scorch, then calender/extrude and cure 8–20 min at 160–180 °C; avoid contamination with sulfur-rich stocks and use ZnO-based halobutyl cure systems.
What is the maximum service temperature of BIIR INNERLINER?
BIIR INNERLINER is rated for continuous use to about 120°C (248 °F), and briefly to 170°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ExxonMobil Bromobutyl 2222/2255 product and compounding bulletins — ExxonMobil Chemical (2021)
- X_Butyl BB 2030/BB X2 halobutyl rubber data sheets — ARLANXEO / Lanxess (2022)
- Engineered Materials Handbook Vol. 2 — Engineering Plastics & Elastomers — ASM International (1988)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications — ASTM (2020)
- ISO 8871 / USP <381> Elastomeric parts for parenterals — ISO / USP (2020)
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.