Linear Low Density Polyethylene (LLDPE)
A straight backbone with short branches of a length you choose. Swapping butene for hexene or octene comonomer changes the toughness of the film far more than any adjustment to melt index will.
Molecular Structure
What is Linear Low Density Polyethylene (LLDPE)?
LLDPE is a copolymer, not a homopolymer, and that is the point. Ethylene is polymerised at low pressure over a Ziegler-Natta or metallocene catalyst together with a small proportion of an alpha-olefin — 1-butene, 1-hexene or 1-octene. The catalyst inserts monomer in a controlled way, so the backbone stays linear and the only branches are the short stubs left by the comonomer, all of the same length.
That controlled architecture gives properties LDPE cannot reach. The chains pack better and entangle less randomly, producing higher tensile strength, much better puncture and tear resistance, and superior dart impact at the same density. Converters use that headroom to downgauge — the same bag at a thinner wall — which is where most of the commercial value sits.
The trade-off is processing. With no long-chain branching there is no strain hardening in the melt, so bubble stability is poorer, motor load and head pressure are higher, and optical clarity is generally worse than LDPE. Blending a proportion of LDPE into an LLDPE film formulation is standard practice for exactly this reason.
The comonomer is the specification that gets overlooked. Butene, hexene and octene grades at identical melt index and density are not interchangeable — longer comonomer means longer side branches, better tie-molecule formation between crystals, and substantially better tear and dart impact. If a film is failing on toughness, the comonomer is usually the first thing to change.
Quick Reference
Key Physical & Chemical Properties
Structure & Bonding
A linear polyethylene backbone carrying short branches of uniform length, set by the alpha-olefin comonomer used. Butene gives ethyl branches, hexene gives butyl, octene gives hexyl — and that single choice governs most of the film properties that matter.
Chain architecture — uniform short branches, linear backbone
Structural Identity
- PolymerLinear low density polyethylene
- Repeat unit(C₂H₄)ₙ with α-olefin comonomer
- Repeat unit mass28.05 g/mol
- ArchitectureLinear backbone, short branches only
- Comonomer1-Butene, 1-hexene, 1-octene
- Branch lengthEthyl, butyl or hexyl respectively
- Made byZiegler-Natta or metallocene, low pressure
- ProcessesGas phase, slurry loop, solution
- Defining propertyTensile, tear and puncture strength
- CAS Number9002-88-4 — generic to polyethylene
- Specified byMFI, density, comonomer, catalyst
Product Specifications
Chelora supplies Linear Low Density Polyethylene (LLDPE) in standard and custom grades. Contact us for specification sheets tailored to your process.
| Polymer | Linear low density polyethylene |
|---|---|
| CAS Number | 9002-88-4 (generic) |
| Repeat unit | (C₂H₄)ₙ with α-olefin comonomer |
| Comonomer | 1-Butene (C4), 1-hexene (C6) or 1-octene (C8) |
| Density | 0.915 – 0.925 g/cm³ (ISO 1183) |
| Melt flow index | 0.5 – 50 g/10 min at 190 °C / 2.16 kg (ISO 1133) |
| Melting range (DSC) | 120 – 125 °C |
| Tensile strength at yield | 10 – 14 MPa |
| Elongation at break | 400 – 800% |
| Dart drop impact (film) | Grade dependent — specify with gauge and comonomer |
| Elmendorf tear, MD / TD | Grade dependent — state which direction governs |
| Catalyst system | Ziegler-Natta or metallocene — specify |
| Volatiles (max) | ≤ 0.10 wt% |
| Ash (max) | ≤ 0.02 wt% |
| Additive package | Antioxidant; slip, antiblock and processing aid to order |
| Food contact | FDA 21 CFR and EU 10/2011 declarations available |
| Bulk density (pellets) | ≈ 550 – 600 kg/m³ |
| Packaging | 25 kg bags, 500 – 1250 kg jumbo bags, bulk |
| Transport classification | Not regulated as dangerous goods |
Downstream Applications & Derivatives
Key derivative chains and industrial uses of Linear Low Density Polyethylene (LLDPE).
Stretch & Cling Film
The signature LLDPE application. Hexene and octene grades give the puncture resistance and elastic recovery that pallet wrap depends on, at gauges LDPE could not survive.
Flexible Packaging Film
Blown and cast film for food packaging, lamination plies and sealant layers, where toughness at low gauge and good seal strength both matter.
Heavy Duty Sacks & Liners
Fertiliser and resin sacks, construction sheeting, pond and landfill liners, where puncture and tear resistance are the failure modes that count.
Agricultural Film
Silage stretch wrap, greenhouse film and mulch, usually as an LLDPE-LDPE blend that trades a little processing ease for substantially better puncture resistance.
Rotational Moulding
Water tanks, chemical tanks, kayaks and playground equipment, using hexene grades with tightly controlled particle size and long-term thermal stability.
Injection Moulding & Pipe
Lids, containers and housewares where stress crack resistance is required, plus small-diameter pipe and drip irrigation tubing.
Why source Linear Low Density Polyethylene (LLDPE) through Chelora Petrochem?
Verified Origin
Full origin certification and asset-backed supply chain documentation — no grey-market or off-spec prime passed as prime.
Grade Flexibility
Butene, hexene and octene grades supplied, Ziegler-Natta and metallocene. We match on comonomer and catalyst as well as melt index and density, because those are what decide whether your film hits its dart and tear targets.
Full Documentation
Technical data sheet, CoA against the grade specification, SDS, REACH compliance, and food-contact declarations under FDA 21 CFR and EU 10/2011 with every shipment.
Logistics Support
Experienced in polymer resin logistics — 25 kg bags, jumbo bags, containerised and bulk silo delivery, with pellet-loss controls in line with Operation Clean Sweep, for Indian and international delivery.
Storage & Handling Guidelines
Always refer to the full SDS before handling. The following is a summary of key requirements.
- Store pellets dry, indoors and out of direct sunlight, with bags off the ground and away from external walls. Surface condensation on cold pellets shows up as bubbles and haze in film.
- Rotate stock and protect from UV. Prolonged sunlight degrades the resin and consumes the antioxidant package before the material ever reaches the extruder.
- Contain pellets rigorously. Spilled pellets travel through drains into watercourses and are a recognised marine litter source — Operation Clean Sweep procedures, catch trays and drain screens should be standard at every transfer point.
- Expect higher extruder load than with LDPE at the same melt index. LLDPE has no long-chain branching, so head pressure and motor amps run higher and the die gap usually needs opening up.
- Blend deliberately rather than by habit. LDPE is added to LLDPE film formulations to restore bubble stability and optics, and the ratio is a real formulation variable that should be recorded and controlled.
- Ground and bond pneumatic conveying, and control fines. Pellet fines cause gels and die build-up as well as presenting a dust explosion risk.
- Extract at the die and hopper. Polyethylene degrading above about 300 °C releases aldehydes including acrolein, plus organic acids, all respiratory irritants.
- Treat molten polymer as a serious thermal burn hazard — it adheres to skin and retains heat, so die changes and purging need forearm and face protection.
- Segregate by comonomer as well as by grade. Butene, hexene and octene resins look identical in the silo and are not interchangeable in the film.
Hazard Summary
Classification: LLDPE in pellet form is not classified as hazardous under CLP. It is chemically inert, non-toxic and used throughout food packaging. The hazards are physical and process-related rather than toxicological.
Thermal burns: molten polyethylene at 180–300 °C adheres to skin and keeps transferring heat after contact. Purging, die changes and screw pulls are where these injuries happen, and protection needs to cover forearms and face rather than hands alone.
Processing fume: polyethylene degrading above roughly 300 °C releases aldehydes including acrolein, organic acids and hydrocarbon fragments, all respiratory irritants. LLDPE is often run hotter than LDPE to compensate for its higher viscosity, so this risk deserves attention rather than assumption.
Dust and fines: pellet fines are combustible and can form explosible clouds in silos, conveying and dust collection. Grounding, bonding and accumulation control apply as for any organic solid.
Pellet loss to the environment: polyethylene pellets persist in the marine environment and are an identified source of microplastic pollution. Containment, drain screening and spill recovery are the expected standard and are increasingly audited by customers and regulators.
Slip hazard: loose pellets on hard flooring cause falls and are a frequent source of lost-time injury in resin handling areas.
Fire: polyethylene burns readily once ignited, with high heat release, dense black smoke and carbon monoxide. Bulk pellet storage fires are hard to extinguish and warrant specific design consideration.
PPE minimum: safety glasses and gloves for pellet handling; heat-resistant gloves, arm protection and face shield for work at the die or on molten material.
Consult the full SDS and the grade technical data sheet for processing temperature limits, and confirm food-contact status for your specific application before use.
Frequently Asked Questions
Technical and commercial questions about Linear Low Density Polyethylene (LLDPE) sourcing and specifications.
What is LLDPE used for?
Stretch and cling film is the flagship application, where its puncture resistance and elastic recovery let pallet wrap run at gauges LDPE cannot survive. Beyond that: flexible packaging film and sealant webs for laminates, heavy duty sacks and form-fill-seal packaging, pond and landfill liners, agricultural silage wrap and greenhouse film, rotational moulding of water and chemical tanks, and injection moulded lids and containers where stress crack resistance is required.
How does LLDPE differ from LDPE in practice?
In toughness and in processability, and the two pull in opposite directions. LLDPE's linear backbone lets chains pack and form tie molecules between crystals, giving markedly better tensile strength, tear resistance and dart impact — which is what allows downgauging. But with no long-chain branching there is no strain hardening in the melt, so the bubble is less stable, extruder pressure and motor load are higher, and clarity is generally poorer. In practice most film formulations blend the two, using LDPE to restore processability and optics while keeping most of the LLDPE toughness.
What does the comonomer choice actually change?
The length of the short branches, and through that, a great deal. 1-butene leaves ethyl branches, 1-hexene leaves butyl, 1-octene leaves hexyl. Longer branches disrupt crystallisation more effectively and, more importantly, promote tie molecules — chains that run through more than one crystallite and hold the structure together. The result is that octene and hexene grades have substantially better tear resistance, dart impact and stress crack resistance than butene grades at identical melt index and density. Butene remains the value option for less demanding film; hexene and octene are what stretch wrap and heavy duty applications use. It is the specification most often left off an enquiry and the one most likely to explain a film failing its dart target.
Why do LLDPE and LDPE share a CAS number?
Because polymer CAS numbers identify a class rather than a discrete substance. CAS 9002-88-4 means polyethylene — ethylene repeat units — and nothing further. Branching architecture, comonomer content, density, molecular weight distribution and catalyst system are all specification properties, not identity properties, so LDPE, LLDPE, HDPE and every grade of each share the number. It serves regulatory paperwork adequately and is nearly useless for procurement, which is why an enquiry needs melt flow index, density, comonomer, catalyst type, additive package and intended process.
What is metallocene LLDPE and when is it worth the premium?
Metallocene catalysts are single-site, meaning every catalyst centre builds chains the same way. Conventional Ziegler-Natta catalysts have multiple different active sites, so the resin is a mixture of chain lengths and comonomer distributions. The single-site result is a narrow molecular weight distribution with comonomer spread evenly along and between chains, which gives better optics, lower seal initiation temperature, higher hot tack and more toughness at a given gauge. It is worth the premium where you are downgauging aggressively, where seal performance on a fast packaging line is the constraint, or where optics matter. It is harder to process — the narrow distribution means less shear thinning — so it usually needs a processing aid and sometimes an LDPE blend component.
What documentation does Chelora provide?
Every shipment includes the grade technical data sheet, a Certificate of Analysis against the grade specification covering melt flow index, density, comonomer type, volatiles and ash; a Safety Data Sheet to GHS and REACH format; REACH polymer compliance confirmation; food-contact declarations under FDA 21 CFR 177.1520 and EU Regulation 10/2011 where applicable; confirmation that the material is not regulated as dangerous goods; an origin certificate; and destination-market certificates where required.
Request a quote or specification sheet
Talk to Chelora's sourcing team about Linear Low Density Polyethylene (LLDPE) grade, volume, logistics, documentation, and lead times. We respond within one business day.
