Rubber & Elastomers•Weathering & Chemical Resistant Elastomers•

VERIFIED(Source-Verified)

Butyl Rubber (IIR)

Primary Designation:ASTM IIR

Aliases:

Isobutylene Isoprene RubberButylPIB Rubber

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Data Completeness:0 composition elements and 1 condition-specific property values cataloged.

Omitted fields represent unverified properties. "Missing is better than invented."

Key Engineering Properties

Representative source rows, qualified by their reported conditions. Inspect the tables below for all values, limits, and source notes.

Service Temp Range

-45°C to 120°CContinuous Limit

Continuous service typically from -45°C ...

Engineering Summary

Butyl Rubber (IIR) is a synthetic copolymer of isobutylene with small amounts (0.5% to 3.0 mol%) of isoprene to provide vulcanization sites. The densely packed methyl side groups along the polyisobutylene chain create an exceptionally tight molecular structure, imparting the lowest gas and vapor permeability of any common industrial elastomer—approximately 8 to 10 times lower than natural rubber. Butyl also exhibits extraordinary energy absorption (high hysteresis) across ambient temperatures, providing superior mechanical shock and vibration damping. It demonstrates good resistance to ozone, weather, dilute mineral acids, and polar chemicals, but poor resistance to petroleum hydrocarbons.

Butyl Rubber (IIR) Documented Applications

›Pneumatic tire inner tubes and tubeless tire innerliner barrier layers (often halobutyl CIIR/BIIR)
›Pharmaceutical vial stoppers, serum bottle closures, and medical syringe plunger tips
›High-damping automotive body mounts, transmission isolators, and acoustic barrier sheets
›Protective chemical gloves, hazardous vapor containment suits, and NBC defense respirators
›Architectural insulating glass (IGU) primary polyisobutylene edge sealants and vacuum membranes

Recognized Aliases

Source-backed commercial trade name and short designations cataloged in canonical data.

Isobutylene Isoprene RubberButylPIB Rubber

Elastomer Technical Profile • Butyl Rubber (IIR)

ASTM D1418: IIRISO 1629: IIRASTM D2000: Type BA

Polymer backbone: Isobutylene-isoprene copolymer. Thermoset and cast elastomer mechanical, thermal, and chemical behavior depends strongly on compounding ingredients, crosslink density, and curing system.

Key Engineering Advantages

•Extremely low gas, air, and moisture vapor permeability (lowest among standard elastomers)
•Superior mechanical vibration, shock, and acoustic damping capacity (high loss factor tan delta)
•Good resistance to atmospheric ozone, UV radiation, and outdoor weathering aging
•Excellent chemical resistance to dilute mineral acids, alkalis, and polar chemical fluids
•Physiologically inert in high-purity pharmaceutical grades (clean extraction profile)

Engineering Limitations & Risks

•Severe degradation and swelling upon exposure to petroleum oils, hydrocarbon fuels, and non-polar solvents
•High internal hysteresis causes severe heat generation under dynamic cyclic mechanical loading
•Slow vulcanization rate and cure incompatibility with highly unsaturated diene rubbers (NR, SBR)
•High cold flow in unvulcanized state requiring specialized handling

Thermal Operating Limits & Service Profile

Min Continuous-45°C

Max Continuous120°C

Max Intermittent / PeakNot specified

Note: Continuous service typically from -45°C to +120°C (-49°F to +248°F) per Parker ORD 5700 Section II (Figure 2-3). Resin-cured compounds achieve higher heat endurance in specialized tire curing bladders. ASTM D2000 heat-aging test temperatures (70h at 70°C for Type AA, 100°C for Type BA) represent accelerated laboratory classification criteria rather than continuous service ratings.

Chemical & Environmental Media Compatibility (Engineering Selection Guide)

Parker ORD 5700 Selection Ratings

Ratings represent manufacturer engineering fluid selection guidance (Parker ORD 5700 / producer design manuals). They do not substitute for batch-specific ASTM D471 / ISO 1817 laboratory immersion testing under service temperature, pressure, and dynamic stress.

Air & Industrial GasesSuperior hermetic retention for nitrogen, oxygen, and compressed air

EXCELLENT

Water & Steam (Resin Cured)Resin-cured butyl withstands hot water and low-pressure steam up to 120°C

GOOD

Dilute Mineral Acids & AlkalisResistant to hydrochloric, sulfuric (dilute), and sodium hydroxide

EXCELLENT

Atmospheric Ozone & UVLow unsaturation (<3 mol%) confers high ozone and weathering resistance

GOOD

Petroleum Hydrocarbon OilsRapid swelling and softening in mineral and lubricating oils

NOT RECOMMENDED

Gasoline & KeroseneSevere solvent dissolution

NOT RECOMMENDED

Compounding & Physical Property Context

Compounding Dependency: Mole percent isoprene unsaturation (0.5% to 2.5 mol%) dictates crosslink density and cure rate. Phenolic resin cures maximize heat resistance and low compression set; sulfur cures provide higher elongation.

Gas & Fluid Permeability: Industry benchmark for low gas permeability; nitrogen diffusion coefficient is roughly one order of magnitude below natural rubber.

Abrasion Endurance: Moderate abrasion resistance; suitable for liners and bladders, unsuited for abrasive slurry impellers.

Tear Resistance: Moderate ASTM D624 Die C tear strength; adequate for tire inner tubes and pharmaceutical stoppers. (Not directly comparable to trouser tear Die T).

Compression Set (ASTM D395): Moderate compression set; resin cure packages yield improved recovery.

Butyl Rubber (IIR) Specifications & Designations

Standard Designations & Applicable Specifications — Semantically classified designations distinguishing primary standard identifiers, commercial trade names, and applicable specification references.

Direct Standard DesignationsDIRECT DESIGNATION

3 Primary Identifiers

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System	Identifier	Standard System Name	Classification Notes & Provenance
ASTMPRIMARY	IIR	ASTM D1418 Nomenclature	—Ref: Standard Practice for Rubber and Rubber Latices—Nomenclature (ASTM D1418-22) / Rubber and latices—Nomenclature (ISO 1629:2013)
ISO	IIR	ISO 1629 Nomenclature	—Ref: Standard Practice for Rubber and Rubber Latices—Nomenclature (ASTM D1418-22) / Rubber and latices—Nomenclature (ISO 1629:2013)
ASTM-D2000	Type BA	ASTM D2000 Classification System	Classified under ASTM D2000 Table X1.1 as Type BA (100°C 70h test); accelerated test temperatures serve classification and do not constitute continuous service ratings.Ref: Standard Classification System for Rubber Products in Automotive Applications (ASTM D2000-21 / SAE J200:2021)

Recognized Commercial Aliases & Trade NamesCOMMON ALIAS

3 Listed

Scroll horizontally for full alias classifications

Recognized Name / Alias	Classification	Technical Usage & Context
Isobutylene Isoprene Rubber	Commercial Alias	Colloquial or commercial industry synonym
Butyl	Colloquial Alias	Colloquial or commercial industry synonym
PIB Rubber	Commercial Alias	Colloquial or commercial industry synonym

Applicable Specifications & Product Form ReferencesSPECIFICATION REFERENCE

3 Applicable Standards

Scroll horizontally for full standard specifications

Standards Body	Specification Code	Specification Title / Scope	Relationship Type
ASTM International	ASTM D1418	Standard Practice for Rubber and Rubber Latices—NomenclatureSTANDARD · Edition: ASTM D1418-22	Specification Reference
ISO	ISO 1629	Rubber and latices — NomenclatureSTANDARD · Edition: ISO 1629:2013	Specification Reference
ASTM International	ASTM D2000	Standard Classification System for Rubber Products in Automotive ApplicationsSTANDARD · Edition: ASTM D2000-21	Specification Reference

Engineering Notice: Applicable specifications establish manufacturing requirements, dimensional tolerances, and test criteria for specific product forms (e.g. bus bar, wire, plate, pipe). They represent applicable technical standards, not alternative or equivalent alloy grades.

Butyl Rubber (IIR) Mechanical Properties

Contextual Mechanical Properties & Tempers: Engineering strength, ductility, and hardness values grouped by product form, temper, and section thickness. Mechanical properties are contextual and not isotropic averages.

Showing 1 of 1 conditions

Scroll horizontally for all conditions & tempers

Product Form	Temper / Condition	Section Size	Tensile (UTS)	Yield Strength	Elongation	Shear Strength	Fatigue Strength	Hardness (Scales Preserved)	Status
Standard Product Form	Standard Gas-Barrier Vulcanizate (Resin Cured) · 70 °C Source values and qualifiers Compression Set (22h at 70°C): 20–45 % (RANGE)Resin-cured formulations achieve 20–30% compression set at 70°C.ASTM D395 Method B / ISO 815-1Parker Hannifin Corporation, Engineered Materials Group — Parker Hannifin Corp. Catalog ORD 5700 (2018/2023), Section II (Basic O-Ring Elastomers: Table 2-2 & Figure 2-3), Section VII (Compatibility Tables) / ASTM D395-18 Method B	—	—	—	—	—	—	—	VERIFIED

Hardness Integrity Notice: Rockwell B (HRB), Rockwell F (HRF), and Superficial 30T (HR30T) scales are reported on their measured scales without cross-scale mathematical conversion.

Source: See fact-level citations

Butyl Rubber (IIR) Processing & Fabrication

Machining, joining, forming, and thermal processing ratings cataloged from the cited authoritative technical reference.

Source: Maurice Morton (Ed.), Springer Science+Business Media

Machinability

Cryogenically frozen below -60°C for precision die cutting and trimming.

Heat Treatment & Working Ranges

Vulcanized via accelerated sulfur packages, phenolic resin cure systems (for high-temperature water/steam endurance), or quinoid cure packages at 150°C to 175°C.

Forming & Cold Working

High cold flow in uncured gum requires careful handling. Compounded on cool roll mills or internal mixers; extruded into inner tubes and calendered into barrier liners.

Butyl Rubber (IIR) Equivalent & Comparable Grades

Comparable Grades & Cross-References: Carefully classified cross-reference relationships for Butyl Rubber (IIR). Comparable does not mean equivalent.

Scroll horizontally for relationship classifications & comparisons

Related Material	Family	Relationship Classification	Metallurgical Notes & Differences	Status	Action
Natural Rubber (NR)	rubber-and-elastomers	Commonly Compared	IIR provides roughly 10x lower air and gas permeability and superior damping; NR provides far superior rebound resilience and dynamic fatigue life.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost).	VERIFIED	Side-by-Side Compare →
Ethylene Propylene Diene Rubber (EPDM)	rubber-and-elastomers	Commonly Compared	Both polymers exhibit good ozone and weather resistance; IIR is chosen for gas and moisture impermeability, while EPDM is chosen for higher temperature continuous steam/hot water service.Materials serve different design priorities (e.g. higher strength vs superior corrosion resistance or cost).	VERIFIED	Side-by-Side Compare →

Related Engineering & Metallurgy Guides

Contextual technical guides explaining degradation mechanisms, testing methodologies, and selection criteria relevant to Butyl Rubber (IIR).

Material Selection18 min read

Types of Rubber: Elastomer Classification, Chemical Resistance & Selection Guide

Selecting the correct rubber is not a matter of choosing a generic flexible polymer—it requires matching molecular backbone chemistry to service temperature, chemical media polarity, dynamic fatigue, and compression set. This engineering guide classifies the 11 primary elastomer families, detailing their ASTM D1418 / ISO 1629 designations, mechanical performance envelopes, and rigorous selection algorithms.

Author: MatGrades Materials Engineering GroupRead Guide →

Material Selection17 min read

What is EPDM Rubber? Properties, Chemistry, Roofing vs Engineering Specifications

EPDM (Ethylene Propylene Diene Monomer) is the global benchmark elastomer for outdoor weathering, hot water, and automotive cooling systems. Its exceptional resistance to atmospheric ozone and steam degradation stems from an entirely saturated polyalkylene backbone with crosslinkable double bonds located exclusively on pendant side groups. This guide breaks down the chemical physics, curing kinetics, and standards governing EPDM specification.

Author: MatGrades Materials Engineering GroupRead Guide →

Material Selection18 min read

Natural Rubber vs Synthetic Rubber: Resilience, Fatigue, Chemistry & Industrial Trade-offs

Despite over a century of synthetic polymer synthesis, natural rubber remains indispensable in modern heavy engineering. Its unique ability to undergo instantaneous strain-induced crystallization grants it dynamic tear strength and fatigue endurance that synthetic random copolymers cannot replicate. However, when service conditions introduce petroleum fuels, atmospheric ozone, or temperatures exceeding 80°C, synthetic elastomers become mandatory. This guide examines the macromolecular physics and industrial trade-offs governing selection.

Author: MatGrades Materials Engineering GroupRead Guide →

Sources

Sources & Provenance Trail: Authoritative reference publications, standards specifications, and data registers cited across this material record.

ASTM International, ISO & Elastomer Engineering Technical CommitteesParker O-Ring Handbook (Catalog ORD 5700) & Elastomer Engineering Selection Guide

Development BenchmarkSTANDARDS ORG

Global engineering seal benchmark establishing continuous operating temperature envelopes (Figure 2-3), elastomer property comparisons (Table 2-2), ASTM D395 Method B compression set benchmarks, and manufacturer engineering fluid compatibility selection ratings (distinguished from raw laboratory immersion coupons).

Issuing Body: Parker Hannifin Corporation, Engineered Materials GroupRevision: ORD 5700 (2018/2023)View Source Record ↗

ASTM International, ISO & Elastomer Engineering Technical CommitteesStandard Practice for Rubber and Rubber Latices—Nomenclature (ASTM D1418-22) / Rubber and latices—Nomenclature (ISO 1629:2013)

STANDARDS ORG

Authoritative international nomenclature defining rubber acronyms and classification families.

Issuing Body: ASTM International & ISO Technical Committee ISO/TC 45 (Rubber and Rubber Products)Revision: ASTM D1418-22 / ISO 1629:2013View Source Record ↗

ASTM International, ISO & Elastomer Engineering Technical CommitteesStandard Classification System for Rubber Products in Automotive Applications (ASTM D2000-21 / SAE J200:2021)

STANDARDS ORG

Standardized classification system establishing Type and Class designations and line callouts for vulcanized rubber compounds.

Issuing Body: ASTM International & SAE International Technical CommitteesRevision: ASTM D2000-21View Source Record ↗

ASTM International, ISO & Elastomer Engineering Technical CommitteesRubber Technology (3rd Edition, Maurice Morton, Ed.) & Processing Specifications

STANDARDS ORG

Authoritative scientific treatise detailing cis-1,4 strain crystallization kinetics, network polysulfidic crosslink reversion at >70°C–80°C in conventional sulfur cures vs semi-EV stabilization, and SBR reinforcement.

Issuing Body: Maurice Morton (Ed.), Springer Science+Business MediaRevision: 3rd EditionView Source Record ↗

Intellectual Property & Provenance Notice: Mat Grades cites technical literature from recognized industry associations and standards organizations. Underlying technical standards and publication data remain the intellectual property of their respective issuing organizations.