CIIR
CIIR is a chlorinated butyl (isobutylene-isoprene) rubber that keeps butyl's low gas permeability and vibration damping while curing faster and co-vulcanizing with diene rubbers such as NR and SBR.
Reference datasheet — CIIR is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the GP-A60 condition
CIIR grades and fills
CIIR is supplied in 11 conditions, soft to hard. GP-A60 is the default FabDigit quotes; the values on this page are for it.
Compare all 11 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Closed-cell sponge / expanded compound | Chemically blown closed-cell butyl sponge for acoustic damping, weatherstrip and low-force gasketing. | 1 | 250 | 20 Shore A | |
Soft grade | Highly plasticized soft compound for low-closure-force gaskets, bladders and vibration pads. | 7 | 700 | 8 Shore D | |
Flame-retardant compound | Choose where UL 94 V-0 or low-smoke performance is required in sealing/insulating rubber parts. | 7 | 350 | 22 Shore D | |
Mineral/clay-filled light-coloured compound | Non-black insulating or colourable compound for electrical parts, white goods and pharma-adjacent sealing. | 8 | 450 | 18 Shore D | |
Low-temperature / high-plasticizer compound | Ester-plasticized compound for seals that must stay flexible below −50 °C. | 8 | 600 | 50 Shore A | |
Tire innerliner compound (high-halobutyl, low permeability) | Pick for tubeless tire innerliners, air-retention bladders and inflatable seals where gas permeability governs. | 9 | 650 | 12 Shore D | |
50 Shore A compound | Soft-medium compound for diaphragms, pharmaceutical stoppers and flexible boots. | 10 | 600 | 11 Shore D | |
GP-A60Default General-purpose black-filled compound, 60 Shore A | Default ZnO/stearic-acid cured carbon-black compound for seals, diaphragms, sheet and general molded goods. | 12 | 500 | 15 Shore D | |
80 Shore A compound | High-filler, stiff compound for extrusion-resistant seals, bumpers and rigid mounts. | 12 | 280 | 28 Shore D | |
70 Shore A compound | Standard sealing hardness for O-rings, valve seats and hose covers under moderate pressure. | 13 | 400 | 20 Shore D | |
CIIR/NR (or CIIR/SBR-EPDM) co-cure blend | Used where halobutyl must be adhered/co-vulcanized to diene rubber — tire sidewalls, innerliner tie-gum, laminated seals. | 15 | 520 | 14 Shore D |
Supply forms, finishes and certifications
Ways CIIR is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOOD | Food-contact / FDA compound | Certification |
PHARMA | Pharmaceutical closure grade | Certification |
What is CIIR?
CIIR is a chlorinated butyl (isobutylene-isoprene) rubber that keeps butyl's low gas permeability and vibration damping while curing faster and co-vulcanizing with diene rubbers such as NR and SBR. Typical compounds show 12 MPa tensile strength, 500% elongation and 1.18 g/cm3 density with service to 140 °C, and are supplied as calendered sheet, extruded profile, molded goods and sponge. It is scorch-sensitive during mixing and bonds poorly without surface treatment or a tie gum. BIIR is the alternative where still faster cure and better co-vulcanization are required. CIIR has a density of 1.18 g/cm³ (0.0426 lb/in³), heavier than 50% of polymer grades. Its glass-transition temperature is -60°C (-76 °F). CIIR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 500% and the elastic modulus is 0 GPa (5.8×10⁻⁴ Msi).
What is CIIR used for?
- Tire innerliners
- Pharmaceutical stoppers
- Adhesive tapes
- Chemical hose linings
Advantages
- Ductile — tolerates forming and impact — 500%, better than 90% of polymer grades
- Good UV / weathering resistance — 88/100, better than 90% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
- High service temperature — 140°C (284 °F), better than 76% of polymer grades
Limitations
- Low stiffness — 0 GPa (5.8×10⁻⁴ Msi), worse than 91% of polymer grades
- Difficult to machine — 30/100, worse than 87% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
- Absorbs moisture — dry before molding — 0.6%, worse than 75% of polymer grades
CIIR properties
Typical room-temperature values for CIIR-GP-A60; bars are the position among polymer grades.
Physical3
CIIR has a density of 1.18 g/cm³ (0.0426 lb/in³), heavier than 50% of polymer grades. Its glass-transition temperature is -60°C (-76 °F).
Mechanical11
CIIR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 500% and the elastic modulus is 0 GPa (5.8×10⁻⁴ Msi).
Thermal8
CIIR is rated for continuous service to 140°C (284 °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 170 µm/m·K (94.4 µin/in·°F).
Electrical5
CIIR is an electrical insulator with a dielectric strength of 24 kV/mm (609.6 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of CIIR takes about 115 MJ of energy and emits 3.6 kg of CO₂ — more than 70% of polymer grades. Typical recycled content is 5%.
Manufacturability5
CIIR's machinability is poor (30/100, worse than 87% of polymer grades); formability excellent (85/100).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. CIIR is highlighted; hover a dot for its name, or open the interactive family chart.
Working with CIIR
Is CIIR easy to machine?
Cured stock is die-cut, waterjet or cryogenically deflashed; conventional machining smears — use sharp, water-lubricated blades and freeze trimming.
Can CIIR be welded?
Not weldable; parts are joined by co-vulcanized splicing, halobutyl-compatible cement, or over-molding onto a primed substrate.
Can CIIR be formed, bent or molded?
Mix below ~120 °C to avoid scorch (halobutyl is scorch-sensitive with ZnO); compression, transfer or injection mold and press-cure 5–15 min at 165–190 °C, or continuous-cure extrude in salt bath/microwave.
CIIR 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 |
|---|---|---|
| isopreneprovides unsaturation/cure sites | 1 – 2.5 | 1.8 |
| Clallylic chlorine cure sites (halogenation level, wt%) | 1 – 1.4 | 1.2 |
| stabilizer (Ca-stearate/epoxidized soybeas supplied in raw bale | 0.5 – 2 | 1.2 |
| carbon black (N550/N660) in default compphr, not wt% of polymer | 40 – 70 | 55 |
| ZnO / stearic acid cure systemphr; MgO added as acid acceptor/scorch control | ≈ 5 | 5 |
| isobutylenepolymer backbone repeat unit | ≥ 96.5 (balance) |
What surface finishes work on CIIR?
Bondability is poor without treatment — chlorination, plasma or a chlorobutyl-based tie gum is needed for adhesion; surfaces can be talc/PTFE-coated or silicone-treated for low tack on stoppers and liners.
How much does CIIR cost?
CIIR is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
CIIR — frequently asked
What is CIIR used for?
CIIR is typically used for tire innerliners, pharmaceutical stoppers, adhesive tapes and chemical hose linings. In short: fast-curing halobutyl; low gas permeability; blends with diene rubbers.
What is the tensile strength of CIIR?
CIIR has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 76% of polymer grades. Strength varies by condition: see the 11 listed tempers.
Is CIIR easy to machine?
Not especially — machinability is rated poor (30/100, worse than 87% of polymer grades). Cured stock is die-cut, waterjet or cryogenically deflashed; conventional machining smears — use sharp, water-lubricated blades and freeze trimming.
Can CIIR be welded?
Not weldable; parts are joined by co-vulcanized splicing, halobutyl-compatible cement, or over-molding onto a primed substrate.
What surface finishes work on CIIR?
Bondability is poor without treatment — chlorination, plasma or a chlorobutyl-based tie gum is needed for adhesion; surfaces can be talc/PTFE-coated or silicone-treated for low tack on stoppers and liners.
Can CIIR be formed, bent or molded?
Mix below ~120 °C to avoid scorch (halobutyl is scorch-sensitive with ZnO); compression, transfer or injection mold and press-cure 5–15 min at 165–190 °C, or continuous-cure extrude in salt bath/microwave.
What is the maximum service temperature of CIIR?
CIIR is rated for continuous use to about 140°C (284 °F), and briefly to 175°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does CIIR cost?
CIIR is a standard-cost polymer ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Exxon™ Chlorobutyl rubber grades 1066/1068 product and compounding data — ExxonMobil Chemical (2021)
- X_Butyl™ CB chlorobutyl rubber technical information — ARLANXEO (2022)
- ASM Engineered Materials Handbook Vol. 2: Engineering Plastics / Elastomer property tables — ASM International (1988)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications — ASTM International (2021)
- ASTM D412 / D624 / D395 / D2240 — tensile, tear, compression set, durometer test methods — ASTM International (2021)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.