Low-density polyethylene (LDPE) is a flexible thermoplastic widely used in films, bags, shrink packaging and extrusion coatings. Its branched molecular structure gives it a combination of softness, melt strength and processing behaviour that is particularly useful in film conversion.

Genesis Polymers Europe supplies Velogy LDPE under the KeyForm and AdvyForm brands. KeyForm includes grades for established film and coating applications. AdvyForm includes specialised options where requirements such as low gel content are central to the finished product.

LDPE structure and key properties

LDPE is made by high-pressure polymerisation of ethylene. Branching along the polymer chains limits how closely they can pack together, producing a less rigid material than HDPE. This structure helps explain why LDPE is commonly selected for flexible products rather than load-bearing rigid components.

For film producers, useful properties include flexibility, heat-sealability and melt strength. Optical quality and surface behaviour vary with the grade, additives, film thickness and conversion conditions. LDPE can provide a useful moisture barrier, but it is not a high oxygen-barrier material; packaging for oxygen-sensitive contents may require a different or multilayer barrier structure.

LDPE is resistant to many aqueous chemicals, although suitability for particular contents or a cleaning agent needs to be checked under the actual conditions of use. Compared with stiffer polyolefins, its lower rigidity and temperature capability can limit applications involving sustained load or elevated temperatures.

LDPE compared with HDPE and LLDPE

LDPE. Structural distinction: Branched chains including long-chain branching. Practical selection focus: Flexible film, melt strength, sealing and coating behaviour.

HDPE. Structural distinction: Much less branching and greater crystallinity. Practical selection focus: Rigid containers, closures and applications requiring higher stiffness.

LLDPE. Structural distinction: Predominantly linear chains with controlled short-chain branching. Practical selection focus: Film strength, puncture resistance and blend design.

LDPE and LLDPE are different materials, even though both can be used in flexible packaging. Film formulations may combine them to balance conversion behaviour and mechanical performance. These comparisons explain polymer selection; they do not imply that every polyethylene family or blend is included in the Genesis Velogy offering.

Processing LDPE into film and coatings

In blown film extrusion, molten LDPE is formed into a tube and expanded into a bubble before cooling and winding. Melt strength helps the bubble retain its shape. Stable production also depends on extrusion conditions, cooling, die design, blow-up ratio and the properties of the complete formulation.

Shrink-film production requires more than a flexible resin. The grade and processing conditions must support the required shrink response, holding force, optical appearance and sealing performance. A heavy-duty shrink hood and a thin display film therefore need different selection priorities.

Extrusion coating applies a molten polymer layer to a substrate such as paper, board or film. The material must suit the coating speed, substrate and required adhesion or sealing function. Not every LDPE film grade is an extrusion-coating grade, even when their density values are similar.

LDPE can also be processed into flexible moulded or extruded articles. Suitability depends on the grade's flow characteristics, the manufacturing method and the stiffness or flexibility needed in the finished part.

Typical LDPE applications

Packaging films and bags use LDPE where flexibility, sealing and practical conversion are important. For lamination film, optical quality and compatibility with printing, adhesive or other layers may drive the specification. The resin, film design and additives should be considered together.

Shrink packaging and pallet protection place more emphasis on melt strength, shrink behaviour and load containment. Film thickness alone does not determine performance: orientation, formulation and sealing conditions affect how the package behaves in use.

Surface protection films require particular attention to gels and other visible defects. Low gel content can be important where defects would affect appearance or contact with a sensitive surface. Low gel does not mean gel-free, and the complete film and adhesive construction must be assessed.

Coated paper and board can use an LDPE layer to provide a sealing or moisture-resistant function. Where packaging contacts food, the documentation must cover the selected grade and intended conditions of use.

Choosing the additive package

Slip and antiblock additives solve different handling problems. Slip additives help adjust surface friction, while antiblock additives help reduce the tendency of adjacent film surfaces to stick together. Their presence can influence film handling and downstream operations, including printing and lamination.

A non-additivated grade can be useful when the converter needs to control the formulation more closely. The right choice depends on the film structure, equipment and final use; there is no single additive package that is best for every film.

Velogy LDPE supplied by Genesis Polymers Europe

KeyForm LDPE includes KeyForm L0400 for applications requiring high melt strength, including shrink and stretch-hood film, and KeyForm L0401 for shrink-film applications where optical properties also matter. KeyForm L0600 is an option for general film applications, while KeyForm L0601 addresses uses such as lamination and shrink film.

The range includes additive variants: KeyForm L0650 and L0850 contain slip and antiblock additives, while KeyForm L0651 contains slip additive. KeyForm L1100 broadens the options for applications including extrusion coating, subject to the specific process requirements.

AdvyForm L0602 is a non-additivated LDPE grade with low gel content for demanding film applications such as surface protection. Its relevance should be assessed against the required film quality and the converter's operating conditions.

Explore the KeyForm and AdvyForm brand pages for the broader portfolio and grade details. Melt flow, density and additives provide a useful starting point, but film trials establish how the resin performs in the actual structure.

Questions about LDPE

Is LDPE suitable for shrink film? Selected LDPE grades are used in shrink film. The required shrink behaviour depends on both the resin and the orientation introduced during processing, so selection should include the film line and packaging operation.

Is LDPE always transparent? No. Clarity and haze depend on the grade, additives, thickness and processing conditions. A film-grade designation alone does not guarantee a particular optical result.

Can LDPE film be recycled? LDPE film can be mechanically recycled in suitable systems. Collection access, cleanliness, inks, adhesives and other layers affect practical recyclability. A flexible package should be assessed as a complete construction against the relevant collection and recycling stream.

A short history of LDPE

High-pressure polyethylene emerged in the 1930s and became the foundation of the LDPE family. Its later development into film and coating grades helped establish flexible polyethylene packaging as a major application for plastics.

Discuss your LDPE requirements

Share your film or coating application, processing method, target thickness, optical requirements and preferred additive package with Genesis Polymers Europe. We can help identify relevant KeyForm or AdvyForm LDPE grades for evaluation on your line.