Polyolefin Elastomer for Film Production: Cast, Blown, and Coextrusion
How POE enhances film properties — seal strength, puncture resistance, and clarity for packaging and industrial applications
Film producers are always balancing competing requirements. You need seal strength for package integrity, puncture resistance for durability, and clarity for product visibility. Often, you need all three in the same film. Polyolefin elastomer has become a key enabler for achieving these combinations — especially in multilayer structures where each layer has a specific job.
We supply POE grades optimized for film applications, from food packaging to industrial stretch wrap. Here's how POE fits into film production — and what to consider when specifying it.
Why POE Works in Film Applications
POE brings a unique combination of properties to film formulations:
- Low seal initiation temperature: POE-rich layers seal at lower temperatures than LLDPE or LDPE, enabling faster packaging line speeds and reduced energy consumption.
- Hot tack strength: The seal strength while still hot — critical for vertical form-fill-seal (VFFS) operations where the seal must support product weight immediately.
- Puncture and tear resistance: The rubber phase absorbs energy, making films more resistant to puncture from sharp edges and tear propagation.
- Clarity: Metallocene POE grades can achieve haze levels below 10% in monolayer films — suitable for many packaging visibility requirements.
Key advantage: POE's compatibility with polyethylene means it can be used in coextrusion with LDPE, LLDPE, or HDPE without tie layers in many applications. This simplifies structure design and reduces cost.
Film Applications for POE
POE finds use across a range of film types, each with specific formulation approaches:
| Film Type | POE Function | Typical Loading |
|---|---|---|
| Food packaging sealant | Low SIT, hot tack, seal strength | 30–100% of sealant layer |
| Stretch film (hand wrap) | Puncture resistance, cling | 10–20% in LLDPE blend |
| Heavy-duty sack | Drop impact resistance, tear strength | 15–30% in LLDPE |
| Medical packaging | Clean peel seal, puncture resistance | 50–80% of sealant layer |
| Agricultural film | Puncture resistance, flexibility | 10–25% in LDPE/LLDPE |
Processing POE in Film Lines
POE processes well on standard polyethylene film equipment, but there are some nuances to be aware of:
Film Processing Guidelines for POE
- Melt temperature: 180–220°C — similar to LLDPE. Higher temperatures can improve clarity but may increase odor in sensitive applications.
- Die gap: POE's higher elasticity means it can handle narrower die gaps without draw resonance issues in blown film.
- Cooling: Faster cooling (higher BUR or chilled rolls) improves clarity by reducing crystallinity. Important for optical film applications.
- Output rates: POE's lower melt strength vs. LDPE may limit maximum output on some blown film lines. Cast film is generally more forgiving.
Coextrusion Structures with POE
Most high-performance packaging films use multilayer coextrusion. POE typically serves as the sealant layer, but can also function as a tie layer or modifier in other layers:
- 3-layer structure (A/B/A): HDPE or LLDPE core (B) for stiffness, with POE-rich sealant layers (A) for seal performance. Total film 40–80 μm.
- 5-layer barrier structure: PET or PA outer, tie, EVOH barrier, tie, POE sealant. POE provides the hermetic seal without requiring a separate adhesive.
- Peelable seal structure: POE blended with PP or specific peel additives creates controlled peel strength for easy-open packaging.
Cost consideration: POE is typically higher cost than LLDPE on a per-kg basis. The economics work when the performance improvement (faster sealing, reduced leakers, downgauging) offsets the material cost increase.
Quality Control for POE Films
Film producers need to verify that POE-containing films meet specifications. Key tests include:
- Seal strength: Peak force to separate a heat-sealed joint. POE-rich sealants typically achieve 15–30 N/15mm depending on thickness and sealing conditions.
- Hot tack: Seal strength measured immediately after sealing while still hot. Critical for VFFS applications.
- Dart drop impact: Measures puncture resistance. POE modification can improve dart drop by 50–100% vs. unmodified LLDPE.
- Haze and clarity: For optical applications. Metallocene POE grades achieve haze <10% at 25 μm thickness.
POE for Film Production
Our POE grades are optimized for cast and blown film processing. Low seal initiation temperature, excellent hot tack, and consistent batch quality for packaging film applications.
Or contact our film applications team for structure recommendations.
