POLYISOBUTYLENE (PIB)

1. PRODUCT IDENTIFICATION

Property	Description
Chemical Name	Polyisobutylene (Polybutene)
CAS Number	9003-27-4
Chemical Formula	(C₄H₈)ₙ
Production Method	Cationic polymerization of isobutene and other C4 olefins
Appearance	Ranges from free‑flowing liquid, to honey‑like viscous liquid, to very sticky semi‑solid materials. All grades are clear, bright, and free from sediment.

PIB is a synthetic hydrocarbon polymer whose physical form (low‑viscosity liquid, high‑viscosity sticky liquid, or semi‑solid) is controlled by adjusting the polymer chain length during polymerization.

2. TYPICAL PHYSICAL AND CHEMICAL PROPERTIES

The following values represent typical ranges for different viscosity grades of PIB. As viscosity increases, molecular weight, density, and flash point generally increase, while bromine number (reactivity) decreases.

2.1. Kinematic Viscosity Grades (cSt)

Viscosity Grade	Min. Viscosity	Max. Viscosity	Test Temperature (°C)
Low 1	3.0	3.7	20
Low 2	3.9	5.0	40
Low 3	5.8	7.2	20
Medium 1	13.5	16.5	40
Medium 2	24.0	30.0	100
Medium 3	11.0	14.0	100
High 1	14.5	16.0	100
High 2	27.5	33.5	100
High 3	48.5	55.5	100
Very High 1	100	115	125
Very High 2	200	235	300
Very High 3	605	670	800
Semi‑solid / Elastomeric 1	2300	2700	400
Semi‑solid / Elastomeric 2	2900	3200	500
Semi‑solid / Elastomeric 3	3900	4200	600
Semi‑solid / Elastomeric 4	3900	4600	700
Semi‑solid / Elastomeric 5	11100	13300	100
Semi‑solid / Elastomeric 6	36000	45000	100

Note: The test temperature varies with viscosity. Low viscosities are measured at lower temperatures (20‑40°C), while higher viscosities are measured at elevated temperatures (100°C and above). Some very high temperature values (e.g., 800°C) may reflect different reference conditions – in practice, high‑viscosity PIB is typically measured at 100°C.

2.2. Molecular Weight and Distribution

Parameter	Test Method	Typical Range
Number Average Molecular Weight (Mn)	GPC (ASTM D 3536 type)	180 – 6000 Da
Polydispersity Index (Mw/Mn)	GPC	1.60 – 1.80

2.3. Color, Flash Point and Water Content

Parameter	Test Method	Typical Value / Limit
Color (Pt‑Co / Hazen)	ASTM D 1209	≤ 50 (for some high‑viscosity grades ≤ 150‑160)
Flash Point (Closed Cup)	ASTM D 93	Min. 65 °C – 180 °C (depends on viscosity)
Water Content	ASTM E 1064 (Karl Fischer)	Max. 40 ppm
Appearance	Visual	Clear, bright, sediment‑free

2.4. Chemical Purity and Reactivity

Parameter	Test Method	Typical Value / Limit
Acid Number (mg KOH/g)	ASTM D 974	< 0.05 – < 0.15
Bromine Number (g Br₂/100g)	ASTM D 2710 / IP 129	3 – 87 (high at low MW, low at high MW)
Chlorine Content (ppm)	XRF	40 – 130 (typically < 100)

2.5. Density and Thermal Properties

Parameter	Test Method	Typical Range
Density at 15.5°C	ASTM D 1298	0.788 – 0.921 g/cm³
Glass Transition Temperature (Tg)	DSC	-69.6°C to -66.9°C (≈ -67°C typical)

3. KEY PROPERTIES (GENERAL)

Permanently non‑drying: Does not harden or skin over by oxidation or UV exposure.
Colorless and stain‑free: Water‑white appearance, leaves no stains.
Solubility: Soluble in aliphatic, aromatic and chlorinated hydrocarbons; insoluble in water, alcohols, acetone, esters.
Compatibility: Compatible with many organic materials (polyolefins, rubbers, paraffinic oils).
Hydrophobicity: Totally water‑repellent; can be emulsified.
Tack and flexibility: Adhesive, transparent, and extensible.
Electrical insulation: Excellent dielectric properties.
Antioxidant nature: Inherent resistance to oxidation.
Lubricity: Good lubricant, non‑corrosive, does not cause corrosion.
Toxicology: Non‑toxic.
Reactivity: Olefinic end groups (especially in low‑medium MW grades) make it reactive – suitable for alkylation, maleic anhydride modification, etc.
Stability: Stable to light and air under ambient conditions.
Low evaporation loss.
High viscosity index (low viscosity change over temperature).
Low pour point (cold flowability).
High temperature behaviour: Leaves no residue or soot upon decomposition.

4. APPLICATION FIELDS (BY VISCOSITY GRADE)

Viscosity Grade	Typical Applications
Low (3 – 50 cSt @ 20‑40°C)	Viscosity index improver in engine oils, synthetic oil base stocks, metalworking fluids, hydraulic oils, industrial greases.
Medium (50 – 200 cSt)	Hot‑melt and pressure‑sensitive adhesives, sealants, plasticizer for PVC, PP, PE; cling layer in stretch films.
High (200 – 1000 cSt)	Automotive sealing compounds, insulating glass sealants, cable filling compounds, rubber modification.
Very High / Semi‑solid (> 1000 cSt)	Reactive fuel additives (detergent / dispersant), lubricant additives, grease thickeners, elastomeric seals, gas barrier films.

5. TEST METHODS (REFERENCE)

Parameter	Test Method
Kinematic Viscosity	ASTM D 445 (or ISO 3104)
Color (Pt‑Co)	ASTM D 1209
Flash Point (Closed Cup)	ASTM D 93
Water Content	ASTM E 1064
Acid Number	ASTM D 974
Bromine Number	ASTM D 2710 / IP 129
Chlorine Content	XRF (X‑Ray Fluorescence)
Density	ASTM D 1298
Glass Transition Temperature	DSC (Differential Scanning Calorimetry)
Molecular Weight (Mn, Mw)	GPC (Gel Permeation Chromatography)
Appearance	Visual (clarity, sediment)

6. SAFETY AND HANDLING SUMMARY

Hazard classification: Not classified as hazardous under normal use. No GHS labelling required.
Skin: Low irritant. Avoid prolonged contact.
Eyes: May cause mechanical irritation; rinse with plenty of water.
Ingestion: Low toxicity but aspiration hazard (may cause chemical pneumonitis if enters lungs). Do not induce vomiting.
Fire: Flammable (especially low‑viscosity grades). Use foam, CO₂, dry chemical or water fog. Do not use a strong water jet (may spread the material).
Storage: Store in a cool, dry, well‑ventilated area away from direct sunlight and heat sources. Typical shelf life in original container: 3 years.
Environment: Not toxic to aquatic life, but spills create a slip hazard and may form a physical barrier on water surfaces.

7. REGULATORY COMPLIANCE (GENERIC)

FDA (USA): Certain molecular weight ranges are compliant for food contact (e.g., 21 CFR 177.1420, 178.3740).
EU / REACH: Registered; may benefit from polymer exemptions.
EU 10/2011: Approved grades available for food contact plastics.
NSF H1: Can be used in food‑grade lubricant formulations.
RoHS, WEEE: Compliant.
PBT / vPvB: Not classified as PBT or vPvB.

8. REMARKS AND LIMITATIONS

This document is based solely on the typical test data and general technical information you provided. It contains no brand names or specific supplier information.
Minor variations may exist between different manufacturers’ products. The user should test for suitability in their own application.
Some high‑temperature test values (e.g., viscosity at 800°C) are above typical polymer service temperatures – they should be interpreted with caution. Normal maximum continuous use temperature is generally below 200°C.
Bromine number indicates reactivity: higher values in low‑MW grades, lower values in high‑MW grades (fewer reactive end groups).

POLYISOBUTYLENE (PIB) – SECTORAL USAGE RATIOS, SELECTION CRITERIA, AND SYNONYMS

This section provides technical guidance on how PIB is used in different industries, the typical concentration ranges in final formulations, the reasons for those ratios, and the criteria for selecting the correct PIB grade (based on molecular weight / viscosity). A list of other names and synonyms used in the industry is also included.

1. ADHESIVES AND SEALANTS

Application	Typical PIB Content (wt% in formulation)	Reason for this ratio	PIB Grade Selected (MW / viscosity)	Selection Rationale
Hot-Melt Adhesive (HMA)	10 – 30%	Provides tack and flexibility; extends open time. Higher ratios reduce cohesion.	Medium MW (Mn ~1300-2500) / 200-1000 cSt @ 100°C	Balance of tack, flexibility, and compatibility with resins and waxes.
Pressure-Sensitive Adhesive (PSA)	5 – 15%	Gives permanent tack. Increasing ratio raises adhesion but may lower shear resistance.	Low to medium MW (Mn ~800-1500)	Low glass transition temperature (Tg ~ -70°C) ensures permanent tack at room temperature.
Insulating Glass (IG) Primary Seal	80 – 95% (main component)	Requires very low gas permeability (butane, xenon) and moisture barrier.	High MW (Mn > 30,000) / solid or semi-solid	Extremely low gas transmission; long-term elasticity.
Automotive Body Sealant (mastic)	15 – 40%	Provides vibration damping, corrosion protection, and adhesion.	Medium MW (Mn ~2000-4000)	Good adhesion, filling properties, compatibility with metals and plastics.

2. LUBRICANTS AND GREASES

Application	Typical PIB Content	Reason for this ratio	PIB Grade Selected	Selection Rationale
Engine Oil Viscosity Index Improver (VII)	5 – 15% (in concentrate)	Maintains fluidity at low temperatures and viscosity at high temperatures. Too high may reduce shear stability.	Low MW (Mn ~500-1500) – conventional or reactive	High viscosity index (>135) and good shear stability.
Industrial Grease Thickener	10 – 30%	Works with soap thickeners; forms a lubricating film.	High MW (Mn ~3000-6000) or semi-solid	Thick, tacky structure; water resistance.
Metalworking Fluids	1 – 5%	Provides lubrication and cooling; leaves no residue or smoke.	Low MW (Mn ~400-800) / low viscosity	Low viscosity for easy spreading; evaporates cleanly at high temperatures.

3. PLASTICS AND PACKAGING

Application	Typical PIB Content	Reason for this ratio	PIB Grade Selected	Selection Rationale
Stretch Film (Cling Layer)	2 – 8% (on film surface)	Higher ratios cause blocking (film sticks to itself).	Medium MW (Mn ~1200-2000)	Provides permanent cling to pallets; non-drying.
PVC Plastisol (Co-plasticizer)	5 – 20%	Compatible with primary plasticizers; gives low-temperature flexibility and permanence.	Low MW (Mn ~600-1000)	Low Tg for flexibility; no plasticizer migration.
Polypropylene (PP) Modification	5 – 15%	Improves flow and impact resistance.	High MW (Mn > 30,000)	Forms an elastomeric phase that toughens PP.

4. COSMETICS AND PERSONAL CARE

Application	Typical PIB Content	Reason for this ratio	PIB Grade Selected	Selection Rationale
Lipstick	5 – 15%	Emollient and film former; provides gloss and wear.	Hydrogenated low MW PIB (Mn ~500-1500)	Colorless, odorless, non-toxic; FDA compliant.
Sunscreen	2 – 10%	Improves water resistance and film formation; stabilises SPF.	Low MW PIB	Hydrophobic barrier; light skin feel.
Hair Gel / Spray	1 – 5%	Gives flexible hold and shine.	Low MW PIB	Good spreadability; controlled tack.

5. FUEL ADDITIVES (Reactive PIB – HR-PIB)

Application	Typical PIB Content	Reason for this ratio	PIB Grade Selected	Selection Rationale
Gasoline Injector Cleaner	10 – 30% (in additive package)	Olefinic end groups (>80% vinylidene) react with amines to remove deposits.	Reactive PIB (Mn ~1000)	High vinylidene content gives high reactivity; low chlorine (<50 ppm).
Diesel Dispersant Additive	5 – 20%	Disperses soot particles; prevents injector deposits.	Reactive PIB (Mn ~800-1200)	Thermal stability; leaves no residue in combustion chamber.

6. GENERAL SELECTION CRITERIA FOR PIB GRADE

The table below summarises how to choose a PIB grade based on required properties.

Selection Criterion	Low MW (300-1000)	Medium MW (1000-3000)	High MW (>30,000)	Reactive PIB (Mn 800-1300)
Viscosity @ 100°C	4 – 50 cSt	200 – 4000 cSt	Solid / semi-solid	100 – 300 cSt
Tack (adhesiveness)	Low	Medium to High	Very high (tape-like)	Medium
Glass Transition (Tg)	~ -70°C	~ -67°C	~ -65°C	~ -67°C
Gas Permeability	High (permeable)	Medium	Very low (barrier)	Medium
Reactivity	Low	Low	None (saturated)	Very high (vinylidene end group)
Solubility	All hydrocarbons	All hydrocarbons	Only aromatics / hot oils	All hydrocarbons
Primary Use	VII, metalworking, oils	Adhesives, cling, gum base	Seals, cable, barrier films	Fuel additives

Key questions to ask when selecting a PIB grade:

What viscosity range is required? (low cSt liquid, honey-like, or solid?)
Is permanent tack needed? (Yes → medium/high MW; No → low MW)
Will it undergo chemical reaction? (Yes → reactive PIB; No → conventional)
Is food or skin contact involved? (Yes → hydrogenated, low MW, low chlorine)
Is a gas barrier needed? (Yes → high MW elastomer)
Must it leave no residue at high temperature? (Low MW evaporates cleanly; high MW degrades)

7. OTHER NAMES AND SYNONYMS FOR PIB (INDUSTRY TERMS)

Term	Description / Note
Polyisobutylene	Full chemical name
Polyisobutene	Common abbreviation (non-IUPAC but widely used)
Polybutene	Caution: polybutene-1 is a different polymer; however some commercial products use this name for PIB.
PIB	Most common abbreviation
HR-PIB	High Reactive PIB – vinylidene content >70%
Hydrogenated PIB	Saturated, non-reactive, more stable; used in cosmetics and food contact.
Conventional PIB	Low reactivity, low terminal double bond content.
Viscosity Index Improver (VII)	Name used when added to engine oils.
Cling additive	Name used in stretch film industry for low MW PIB.
Polyisobutylene (IUPAC)	International chemical name.
Note: Butyl rubber	Is a copolymer of isobutene and isoprene; it is NOT PIB. Do not confuse.

8. SUMMARY TABLE – WHICH PIB, WHERE, AND AT WHAT RATIO

Sector	Typical Ratio in Final Product	PIB Type Selected	Primary Selection Reason
Pressure-Sensitive Adhesive (PSA)	5 – 15%	Medium MW (~1500)	Permanent tack
Hot-Melt Adhesive (HMA)	10 – 30%	Medium MW (~2000)	Flexibility + open time
Insulating Glass Sealant	80 – 95%	High MW (>30k)	Gas barrier
Engine Oil VII	5 – 15%	Low MW (500-1500)	Viscosity index
Stretch Film Cling	2 – 8% (surface)	Medium MW (~1300)	Cling effect
Lipstick	5 – 15%	Hydrogenated low MW	Colorless, safe
Fuel Additive	10 – 30%	Reactive PIB (1000 Mn)	Vinylidene reactivity

Polyisobutylene, Polyisobutene, Polybutene, PIB, HR-PIB, 9003-27-4