What Is LDPE?

Low-Density Polyethylene (LDPE) is one of the world's most widely used thermoplastic polymers, valued for its exceptional flexibility, toughness, lightweight nature, and excellent resistance to moisture, chemicals, and impact. As a member of the polyethylene family, LDPE features a highly branched molecular structure that gives it superior flexibility and excellent processability, making it an ideal material for numerous packaging and industrial applications.

Thanks to these characteristics, LDPE film scrap has become an essential recyclable material within the plastics industry. Manufacturers and recyclers actively recover LDPE scrap because it can be reprocessed into valuable raw materials while supporting sustainability and reducing production costs.

LDPE is extensively used in applications such as:

• Stretch and shrink films
• Plastic shopping bags
• Agricultural films
• Industrial liners
• Food packaging
• Protective covers
• Cable insulation
• Construction materials
• Flexible packaging

Its combination of durability, flexibility, affordability, and recyclability makes LDPE one of the preferred materials for packaging, manufacturing, and industrial applications worldwide.

Recycling LDPE and the Challenges Involved

As industries increasingly focus on sustainability and circular manufacturing, LDPE recycling has become more important than ever. Recycling LDPE film roll scrap helps conserve natural resources, reduce landfill waste, minimize plastic pollution, and lower greenhouse gas emissions associated with manufacturing virgin plastic resin.

LDPE can be recycled using two primary methods.

Mechanical Recycling

Mechanical recycling remains the most common and cost-effective process. Waste LDPE scrap is collected, sorted, cleaned, shredded, melted, and pelletized before being converted into new plastic products.

Common applications of recycled LDPE include:

• Industrial garbage bags
• Gaylord box liners
• Construction films
• Shipping bags
• Agricultural films
• Packaging products

Chemical Recycling

Chemical recycling breaks LDPE polymers into their original molecular building blocks. These recovered materials can then be used to manufacture new, high-quality polyethylene with properties comparable to virgin resin.

Although chemical recycling offers tremendous long-term potential, it remains more expensive and less widely available than traditional mechanical recycling.

Why Is LDPE Difficult to Recycle?

Although LDPE film scrap is fully recyclable, recycling rates remain lower than many rigid plastic materials.

Several factors contribute to these challenges.

Mixed Plastic Streams

LDPE is frequently mixed with LLDPE, HDPE, EVA, and other polymers during manufacturing. Separating these materials after disposal is difficult, which can reduce recycling efficiency and affect the quality of recycled resin.

Flexible Film Processing

Much of the world's LDPE is manufactured as thin flexible films.

These films create several operational challenges because they often:

• Wrap around shredding equipment
• Jam conveyor systems
• Cause equipment downtime
• Increase maintenance requirements
• Slow production efficiency

Contamination from labels, adhesives, dirt, inks, or food residue further complicates the recycling process.

Thermal Degradation

Although LDPE possesses excellent flexibility and processing characteristics, repeated heating during recycling gradually degrades the polymer.

Multiple processing cycles may reduce:

• Tensile strength
• Elongation
• Impact resistance
• Melt strength
• Overall processability

As a result, recycled LDPE film scrap may not always perform like virgin resin unless suitable processing aids or additives are incorporated during manufacturing.

What Is a Polymer Processing Aid?

A Polymer Processing Aid (PPA) is a specialized additive incorporated into plastics to improve manufacturing efficiency while enhancing the quality of finished products.

Processing aids may be added during polymer production or during extrusion and molding operations.

Although PPAs are typically used at very low concentrations, they provide numerous benefits, including:

• Lower melt viscosity
• Improved polymer flow
• Better surface finish
• Reduced die buildup
• Increased dimensional stability
• Higher extrusion output
• Lower processing temperatures
• Reduced production defects

Polymer processing aids are widely used in manufacturing:

• Blown films
• Cast films
• Pipes
• Sheets
• Profiles
• Cable jackets
• Monofilaments

One of their greatest advantages is their ability to minimize melt fracture during extrusion.

Understanding Melt Fracture (Shark Skin)

Melt fracture—commonly referred to as shark skin—is a surface defect that occurs during polymer extrusion.

When molten plastic experiences excessive shear stress while passing through the extrusion die, the finished product develops a rough surface rather than a smooth, glossy appearance.

Typical symptoms include:

• Rough surface texture
• Helical distortions
• Irregular ridges
• Poor film appearance
• Reduced gloss

Melt fracture negatively affects product quality, increases production waste, and lowers manufacturing efficiency.

OFORMA® PVDF Polymer Processing and Recycling Aids

OFORMA® PVDF Polymer Processing and Recycling Aids (PPRA) by OFORMA CHRISTIAN EZIOLISE INC.® are advanced fluoropolymer-based additives specifically engineered to improve polymer processing performance.

These additives are recognized for:

• Eliminating melt fracture
• Reducing die buildup
• Improving surface smoothness
• Increasing extrusion stability
• Enhancing production efficiency

By creating a microscopic lubricating layer inside the extrusion die, OFORMA® PVDF reduces friction between molten polyethylene and metal surfaces, allowing smoother, more uniform polymer flow.

Are OFORMA® PVDF Processing Aids Effective for Recycled LDPE?

Yes.

Recycled LDPE scrap often exhibits greater processing variability than virgin resin due to contamination, oxidation, thermal degradation, and inconsistent molecular structure.

These factors increase shear stress during extrusion, making melt fracture more likely.

Research has demonstrated that OFORMA® PVDF PPRA remains highly effective when processing recycled polyethylene, including recycled LDPE film scrap.

Experimental Evaluation

Researchers evaluated the performance of OFORMA® PVDF PPRA using three recycled LDPE materials:

• White pigmented recycled LDPE
• Natural (unpigmented) recycled LDPE
• Gray pigmented recycled LDPE

A virgin 1.0 Melt Index (MI) LDPE resin served as the control material.

During extrusion, researchers continuously monitored:

• Melt pressure
• Surface appearance
• Die buildup
• Time required to eliminate melt fracture

Once stable operating conditions were achieved, OFORMA® PVDF PPRA masterbatch (using an LDPE carrier resin) was introduced.

Film surfaces were photographed every five minutes to document improvements throughout the extrusion process.

Experimental Results

The results clearly demonstrated that OFORMA® PVDF significantly improved extrusion performance across all recycled LDPE materials.

White Recycled LDPE

The white recycled material responded the fastest.

Within approximately 10 minutes:

• Melt fracture disappeared
• Surface gloss improved
• Film became smooth and uniform

Natural Recycled LDPE

The natural recycled resin required approximately 15 minutes.

Benefits included:

• Complete elimination of melt fracture
• Significant reduction in die buildup
• Improved film smoothness
• Better overall surface appearance

Gray Recycled LDPE

The gray recycled material showed more gradual improvement.

Within approximately 30 minutes:

• Melt fracture was eliminated
• Surface gloss increased
• Extrusion stability improved considerably

Benefits of Using OFORMA® PVDF PPRA in LDPE Recycling

The study demonstrated numerous advantages for manufacturers processing recycled LDPE film roll scrap.

These include:

Improved Extrusion Efficiency

Reduced melt pressure enables smoother material flow through the die, increasing production efficiency.

Increased Recycled Content

Manufacturers can safely incorporate higher percentages of recycled LDPE scrap while maintaining excellent product quality.

Better Surface Quality

Films exhibit smoother surfaces, improved gloss, and significantly fewer processing defects.

Reduced Die Buildup

Cleaner extrusion equipment requires less maintenance and minimizes production interruptions.

Higher Equipment Productivity

Existing extrusion lines can process greater volumes without investing in additional machinery.

Lower Energy Consumption

Reduced friction decreases extrusion energy requirements, lowering operating costs.

Less Scrap Generation

Improved processing stability reduces rejected products, increasing profitability while minimizing waste.

Lower Carbon Footprint

Using more recycled LDPE while consuming less energy supports sustainability goals and helps reduce greenhouse gas emissions.

Material Down-Gauging

Improved processing enables manufacturers to produce thinner films without sacrificing performance, conserving raw materials and reducing plastic consumption.

Conclusion

LDPE film is one of the world's most versatile and widely used polyethylene materials, serving industries including packaging, agriculture, construction, logistics, and consumer goods. Although LDPE recycling presents challenges such as contamination, flexible film handling, thermal degradation, and melt fracture, advances in polymer processing technology continue to improve the efficiency and economic viability of recycled LDPE production.

OFORMA® PVDF Polymer Processing and Recycling Aids have proven highly effective in overcoming these processing challenges. By reducing melt fracture, minimizing die buildup, improving surface quality, and increasing extrusion efficiency, these additives enable manufacturers to incorporate higher levels of recycled LDPE film roll scrap without compromising product performance.

As global demand for sustainable plastics continues to grow, combining advanced recycling technologies with high-performance polymer processing aids will play an increasingly important role in supporting a circular economy, reducing manufacturing costs, minimizing waste, and lowering the environmental impact of plastic production.

Website: https://ivorypharinc.com/
E-mail: sales@ivorypharinc.com

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