Butyl Rubber
The most gas-impermeable rubber in commercial use — the elastomer behind tire inner tubes and innerliners, and a core ingredient in chewing gum base, adhesives and sealants.
Chelora Chemicals supplies butyl rubber to tire, sealant and adhesive manufacturers worldwide, with full documentation and consistent polymer quality on every consignment.
Product identity
- CAS Number
- 9010-85-9
- Polymer type
- Isobutylene-isoprene copolymer
- Isoprene content
- 0.5-2.5 mol%
- Density
- ~0.92 g/cm³
- Service temperature
- -40 °C to 120 °C
- Physical form
- Solid bales / crumb
- UN Number
- Not regulated*
- HS Code
- 4002 31
* Solid butyl rubber is not classified as dangerous goods under standard conditions; confirm classification for any compounded or solvent-bearing grades with your regulatory affairs team.
What Butyl Rubber is used for
Butyl Rubber (IIR) is a solid synthetic rubber — a copolymer of isobutylene with a small amount of isoprene, which provides sites for vulcanisation. Its tightly packed, saturated backbone gives it the lowest gas and moisture permeability of any common rubber. Supplied as bales or crumb, it is compounded with fillers, oils and curatives before processing.
Butyl rubber's single largest use is in tire inner tubes and tire innerliners, where its gas impermeability keeps tires inflated for extended periods. Its second major use is as the base elastomer for chewing gum, prized for its chew texture and food-contact suitability in food-grade purity. Butyl rubber is also widely used in adhesives, sealants, roofing membranes, and pharmaceutical vial closures, wherever a tight barrier to gas and moisture is required.
Where it sits in the elastomer value chain
- Isobutylene & Isoprene the monomer feedstocks butyl rubber is copolymerised from.
- Butyl Rubber (this product) the copolymer base resin supplied to compounders and converters.
- Halobutyl Rubber chlorinated or brominated variants used where faster cure and better compatibility with general-purpose rubbers is needed.
Handling character
Butyl rubber is a solid, low-hazard elastomer under normal storage and handling. Full hazard detail is in the Safety section below.
| Parameter | Typical value |
|---|---|
| Appearance | Solid bales or crumb, off-white |
| Isoprene content | 0.5-2.5 mol% |
| Mooney viscosity | Within producer specification |
| Unsaturation | Within producer specification |
Important: the figures above are indicative of commercial material and are offered for planning only. The batch certificate of analysis is the governing document.
| Property | Value |
|---|---|
| Physical state | Solid elastomer (bales/crumb) |
| Density | ~0.92 g/cm³ |
| Service temperature | -40 °C to 120 °C |
| Gas/moisture permeability | Lowest of common rubbers |
| Ozone/weathering resistance | Excellent |
| Oil/fuel resistance | Poor (use nitrile grades instead) |
Physical constants compiled from public reference data for CAS 9010-85-9 and rounded for readability. Treat them as orientation, not as a specification.
Where our customers put this rubber to work
The elastomer the tire, gum and sealant industries rely on for an airtight barrier.
Tire inner tubes & innerliners
The standard elastomer for keeping tires inflated, thanks to its exceptional gas impermeability.
- Tire-grade specification
- Bulk & bale supply
- Technical desk review on request
Chewing gum base
Food-grade butyl rubber supplied for chew texture and structure in gum base formulation.
- Food-grade specification
- Documented batch traceability
- Contract & spot supply
Adhesives & sealants
Used in construction and automotive sealants and pressure-sensitive adhesives for their barrier properties.
- Packs sized to customer volumes
- Full analytical documentation available
- Retained sample held against the lot
Roofing & waterproofing membranes
Used in roofing and flashing membranes where a low-permeability moisture barrier is required.
- Documented batch traceability
- Technical desk review on request
Pharmaceutical closures
Vial stoppers and seals where low gas/moisture transmission protects sensitive formulations.
- Research & process-scale quantities
- Full documentation supplied
Contract & scheduled supply
Tire and sealant plants running continuous consumption are supported with scheduled bulk delivery.
- Annual contracts with scheduled call-off
- Price held across the contract period
- Second source held in reserve
How we supply Butyl Rubber
Chelora Chemicals is a supplier and sourcing partner, not a manufacturer. Isoprene content and Mooney viscosity are critical to cure rate and barrier performance — that shapes how we manage this line.
We place your order with whichever qualified producer best matches your required grade, your price point and your delivery window, and confirm your jurisdiction's import requirements before booking.
We keep a second qualified source on this line, so a single-plant disruption never becomes your production problem.
- Isoprene content and Mooney viscosity confirmed before we quote. Consistency matters to downstream cure and barrier performance.
- Transport documentation managed end to end. Classification, labelling and carrier compliance confirmed before booking.
- Scheduled call-off scheduling. We hold contracted tonnage and release it against your consumption calendar.
- Batch traceability to the producing plant. Full chain of custody documentation on request.
- Export machinery handled in-house. Classification, approved packing, labelling, freight booking and customs paperwork are ours to manage.
- Standard and halobutyl grades both sourced. Matched precisely to your compounding and cure system.
Packed the way your plant receives it
Bale or bulk bag — tell us your preferred format and we will quote and classify to it.
25-35 kg polywrapped bales
Palletised, shrink-wrapped bales for smaller-volume orders and trial quantities.
~500-1,000 kg crumb bags
FIBC bulk bags for crumb grades sized for mid-volume compounder orders.
Full-container-load shipment
Palletised bale loads in standard containers for continuous-consumption tire and compounding plants.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with documentation filed before booking.
Trial / sample quantities
Small packs dispatched for process trials before a commercial order is placed.
Contracted call-off supply
We hold contracted tonnage and release it against your consumption calendar.
A low-hazard solid elastomer — handled with standard care
Solid butyl rubber bales and crumb are not classified as hazardous under normal conditions. The summary below is orientation only — the safety data sheet supplied with your specific batch is the authoritative document.
Processing hazards to manage
DustNuisance dust from crumb handling; use standard dust controls.FumesVulcanisation and processing fumes require adequate ventilation.
Low intrinsic hazard, standard industrial hygiene applies. Always read the SDS issued with your specific batch and compound for complete handling guidance.
Storage
Store bales and crumb in a cool, dry area away from direct sunlight and ozone sources. Butyl rubber's own ozone resistance is excellent, but compounded or blended stock should still be rotated.
Handling
Use standard PPE (gloves, dust protection) for bale and crumb handling. Provide local exhaust ventilation at compounding, extrusion and vulcanisation stations, particularly for halobutyl grades.
Transport
Solid butyl rubber is generally not regulated as dangerous goods. We confirm and document classification for any compounded, oil-extended or solvent-bearing grade specific to your shipment.
Every batch, documented
We verify documentation before dispatch so there are no surprises at your incoming-goods bench.
Specification agreed
Isoprene content and Mooney viscosity confirmed against your compound before order placement.
Producer batch testing
The producing plant tests each batch against the agreed specification before release.
Documentation review
COA, SDS and transport paperwork checked by our desk before the shipment is booked.
Traceable dispatch
Each shipment is traceable to its producing batch, with full chain-of-custody records on request.
How butyl rubber is made
Butyl rubber is produced industrially by the cationic copolymerisation of isobutylene with a small amount of isoprene at low temperature, a long-established route in elastomer chemistry. The low isoprene content leaves just enough unsaturation for sulphur vulcanisation while preserving the saturated backbone responsible for its gas impermeability.
We do not publish operating process parameters here; this is background only. Full technical documentation accompanies every shipment, and any process-specific detail you need is best confirmed directly with our technical desk.
| Chemical family | Isoolefin-diene copolymer |
|---|---|
| Functional groups | Residual isoprene unsaturation |
| Reactivity | Sulphur or resin vulcanisation at diene sites |
| Related compounds | Isobutylene, Isoprene (feedstocks), Halobutyl Rubber (related grades) |
Explore the wider elastomer range
Butyl Rubber, answered
What is Butyl Rubber used for?
Why is butyl rubber so gas-impermeable?
Is Butyl Rubber hazardous?
What grade do you supply?
What packing do you offer?
Do you manufacture this yourself?
- Need a related elastomer? See our EPDM Rubber and Nitrile Rubber pages.
Get a quote on Butyl Rubber today
Send us your required grade, pack size and delivery window. We will come back with a firm quote, lead time and full documentation.