Why Are PVDC Co-Extruded Films Replacing Traditional Laminated Films?
In high-barrier food packaging, material selection directly determines shelf life, product appearance, and export reliability. Since its commercial introduction in the mid-20th century, PVDC (polyvinylidene chloride) has remained one of the most recognized high-barrier polymers in the industry, valued for its outstanding oxygen and moisture barrier performance.
As global food trade expands and long-distance sea transportation becomes increasingly common, packaging materials are required to maintain stable barrier performance across diverse climates. Against this backdrop, MA-PVDC-based multi-layer co-extruded films are steadily replacing traditional PVDC laminated films and becoming the preferred solution for premium food packaging applications.
This transition is not a short-term market fluctuation. It is driven by measurable performance data, process innovation, and evolving regulatory expectations.
- 🔹Raw Materials and Processes: Similar Origins, Vast Differences
1.1 Laminated Films: VC-PVDC Based “Two-Step” Process
PVDC laminated films usually adopt VC-PVDC raw materials and produce single-layer PVDC casing films through a “double-bubble” process. These casing films typically have a thickness of 22–25 μm and a width not exceeding 1100 mm. They were initially designed for sausage packaging applications.
After production, an adhesive lamination process is required to bond the PVDC film layer with substrates such as PP or PE. This “two-step” process relies on adhesives, which not only introduces risks of solvent residue but also results in limited interlayer bonding strength. Delamination may occur during subsequent processing and use.
1.2 Co-Extruded Films: MA-PVDC Based “One-Step” Forming Process
PVDC co-extruded films use MA-PVDC raw materials and employ multi-layer co-extrusion blown film technology. MA-PVDC is co-extruded with PE, PP, PA and other materials in a single melt-forming process, with the PVDC layer serving as the barrier layer.
This “one-step” process does not require any adhesive. Layers are fused naturally through thermal bonding, resulting in a more stable structure and better environmental performance. Due to the characteristics of MA-PVDC materials, even when the PVDC barrier layer thickness is only 5 μm, the film can still achieve barrier performance far superior to laminated films.
1.3 Fundamental Differences Brought by Process Variations
The international plastics industry generally defines materials with oxygen transmission rates below 10 ml/(m²·24h·atm) as high-barrier materials.
PVDC casing films produced using VC-PVDC materials typically have oxygen transmission rates around 30 ml (based on GB/T 17030-2008 standards). In contrast, co-extruded films produced using MA-PVDC can easily achieve oxygen transmission rates below 3 ml.
These data directly demonstrate the performance gap between the two materials and explain why co-extruded films are regarded as the next generation of high-barrier materials.
- 🔹Practical Performance in Real Food Applications
Technical specifications are important, but real-world packaging results are even more persuasive.
2.1 Color Stability and Oxidation Resistance
When laminated PVDC films are used for products such as flavored sausages or corn hot dogs, noticeable oxidation and discoloration often appear after 45 days of storage.
The higher oxygen permeability allows gradual oxygen penetration, leading to pigment degradation and flavor loss.
PVDC co-extruded films, by contrast, significantly reduce oxygen exposure and help maintain original color and sensory quality throughout extended shelf life.
2.2 Moisture Control and Prevention of “Water Release”
For high-moisture foods, insufficient moisture barrier performance can lead to condensation or internal “water release” after extended storage (typically beyond 60 days). This affects both product texture and consumer perception.
Many industrial meat processors therefore avoid laminated structures for long-shelf-life products.
PVDC co-extruded films provide superior moisture barrier performance, effectively reducing dehydration and maintaining product juiciness and texture stability.
- 🔹Broad Application Coverage: From Chilled Storage to High-Temperature Sterilization
3.1 Shrink Packaging for Fresh Meat
In fresh meat shrink packaging applications, PVDC co-extruded films offer high shrink ratios and excellent conformity to product surfaces.
By minimizing oxygen exposure, they help delay myoglobin oxidation and preserve the bright red appearance required in export-grade chilled meat packaging.
3.2 High-Temperature Retort Packaging
PVDC co-extruded films can withstand sterilization at 125°C for 30 minutes without seal failure.
Unlike some alternative high-barrier materials, PVDC maintains stable barrier properties even after retort processing, ensuring long ambient shelf life.
The high heat-seal strength further reduces the risk of seal breakage during thermal sterilization.
3.3 Thermoforming Films and Lidding Films
Thanks to excellent deep-draw performance and flexibility, PVDC co-extruded films are well suited for thermoforming packaging systems.
They can adapt to various tray geometries—rectangular, circular, or irregular—while maintaining uniform thickness and barrier integrity.
3.4 Refrigerated and Low-Temperature Applications
In chilled storage environments (0–4°C), PVDC co-extruded films maintain flexibility and resist brittleness.
They are widely used in packaging for chilled meat, cheese, soy-based products, and ready-to-eat foods, where stable barrier performance under low-temperature conditions is essential.
Q1: How does PVDC co-extruded film compare to EVOH retort films?
EVOH offers excellent oxygen barrier performance under dry conditions. However, its barrier properties decrease significantly in high-humidity environments.
PVDC, by contrast, maintains stable oxygen barrier performance regardless of humidity.
For retort packaging, this stability ensures that even after high-temperature sterilization, the packaging continues to provide long-term shelf life protection.
Additionally, PVDC co-extruded films typically exhibit stronger heat-seal integrity during sterilization.
Q2: Is PVDC co-extruded film recyclable and compliant with European regulations?
Yes.
Modern PVDC co-extruded films are designed with PE/PVDC structures and do not require adhesive lamination. This mono-material-oriented structure is compatible with existing polyethylene recycling streams.
Current research confirms that such structures can enter mechanical recycling systems and be reprocessed into secondary plastic products, aligning with European packaging recyclability requirements under PPWR.
Q3: Which is better for meat packaging: PVDC or EVOH?
The choice depends on the application environment.
EVOH is suitable for dry products or controlled-humidity packaging.
PVDC is more reliable for high-moisture meat products, retort applications, long-term refrigeration, and export shipments through high-temperature and high-humidity regions.
In practice, many processors report improved color stability and reduced moisture-related issues when switching from EVOH to PVDC co-extruded structures.
In food packaging, cost reduction and efficiency improvement do not start at the production line—they start with material selection. With significantly lower oxygen transmission rates, solvent-free structural integration, humidity-resistant barrier performance, and strong process adaptability, PVDC co-extruded films are steadily replacing traditional laminated PVDC films and other medium-barrier materials worldwide. The shift is not promotional—it is performance-driven.
