EVOH, PVDC and High-Barrier Flexible Packaging Structures Explained
EVOH, PVDC, Adhesives, Coatings, Primers and Inks in Flexible Packaging: What They Do and Why They Matter
A practical guide to oxygen barrier materials, multilayer packaging structures, and responsible packaging development
Flexible packaging may look simple from the outside.
A pouch, sachet, flow wrap, lidding film, bag, or laminate may appear to be one single material. In reality, high-performance flexible packaging is often a carefully engineered structure made from several layers, coatings, primers, adhesives, inks, and sealants.
Each part has a job.
• Some layers provide strength.
• Some layers support sealing.
• Some layers help protect against oxygen.
• Some layers help control moisture.
• Some layers support printing.
• Some layers help the package survive filling, shipping, storage, and consumer handling.
Among these materials, EVOH and PVDC are two important oxygen barrier materials. They are often used when the product needs protection against oxygen, aroma loss, moisture, or external contamination.
But EVOH and PVDC do not work alone.
Adhesives, coatings, primers, and inks complete the structure.
That sentence is important because many packaging discussions focus only on the “main material” or the “barrier layer.” In real packaging development, the final performance of a pack depends on the complete structure, not one material in isolation.
A flexible package is a system.
That system must protect the product, maintain shelf life, seal correctly, run on commercial lines, survive distribution, support regulatory requirements, and increasingly align with recyclability and sustainability expectations.
This article explains what these materials do, what they do not do, and how packaging teams should think about them when developing high-barrier flexible packaging.
What is a multilayer flexible packaging structure?
A multilayer flexible packaging structure is a combination of different layers designed to deliver specific packaging functions.
A simple flexible packaging structure may include only one or two layers. A more demanding structure may include several films, coatings, primers, adhesives, inks, and sealants.
A typical multilayer structure may include:
• Outer print layer
• Ink system
• Primer or coating
• Adhesive layer
• Barrier layer
• Tie layer
• Core film
• Sealant layer
Each layer is selected because it contributes something to the final pack.
The outer layer may provide stiffness, printability, heat resistance, and appearance. The barrier layer may protect against oxygen or moisture. The adhesive bonds films together. The primer improves adhesion or surface compatibility. The ink creates the brand communication. The sealant layer closes the pack and protects the product from leakage.
This is why flexible packaging is technically complex.
The package must work as one structure, but each part has a different responsibility.
Why oxygen barrier matters
Oxygen is one of the biggest reasons packaged products lose quality.
Oxygen can cause oxidation, rancidity, flavor loss, color changes, aroma degradation, vitamin loss, texture change, and shelf-life reduction. The exact impact depends on the product.
Oxygen-sensitive products may include:
• Coffee
• Nuts
• Snacks
• Meat products
• Cheese
• Ready meals
• Sauces
• Soups
• Pet food
• Baby food
• Pharmaceutical products
• Medical products
• Powders
• Dried ingredients
• Industrial components
In these applications, oxygen barrier packaging helps reduce oxygen transmission into the pack.
The technical measurement often used is OTR, or oxygen transmission rate.
OTR measures how much oxygen passes through a film or packaging structure under defined test conditions. Lower OTR generally means stronger oxygen barrier performance.
But OTR must always be interpreted in context. Temperature, humidity, film thickness, lamination, coating quality, flex cracking, filling conditions, storage conditions, and final pack design can all affect performance.
This is why packaging teams should not only ask:
“What is the OTR value?”
They should ask:
“What oxygen barrier does this product require under the real conditions of processing, storage, distribution, and shelf life?”
That is the packaging development question that matters.
EVOH: what it is and what it does
EVOH stands for ethylene vinyl alcohol.
It is a copolymer often used as an oxygen barrier layer in food packaging and other high-barrier packaging applications.
EVOH is valued because it can provide excellent oxygen barrier performance, especially under dry or moderate humidity conditions. It is often used as a thin layer in coextruded films, trays, bottles, thermoformed structures, pouches, and flexible packaging laminates.
In packaging, EVOH helps slow oxygen transmission. This can help preserve product quality, aroma, flavor, color, and shelf life.
EVOH is especially relevant when packaging teams need transparent oxygen barrier performance. Unlike aluminum foil, EVOH can be used in transparent or semi-transparent structures, depending on the rest of the package.
Common applications may include:
• Meat packaging
• Cheese packaging
• Fresh pasta
• Ready meals
• Sauces
• Condiments
• Medical packaging
• Coffee packaging in selected structures
• Thermoformed trays
• Vacuum packaging
• Modified atmosphere packaging
EVOH is not usually the main structural layer. It is often used as a thin functional barrier layer protected by other polymers.
What EVOH does well
EVOH is strong in oxygen barrier performance.
It helps protect oxygen-sensitive products and can support longer shelf life when used correctly. It is also useful in transparent packaging structures where aluminum foil is not desired.
EVOH can be coextruded with polyolefins such as PE or PP, often with tie layers to help compatibility. This allows packaging engineers to place EVOH inside a multilayer structure where it can do its barrier job while being protected by other layers.
EVOH also helps packaging teams develop structures with a very thin barrier layer. In many applications, only a small percentage of EVOH may be needed to deliver oxygen barrier performance.
Its main strengths include:
• Excellent oxygen barrier in suitable conditions
• Transparency
• Suitability for thin barrier layers
• Use in coextruded structures
• Compatibility with many food packaging applications
• Support for shelf-life extension
• Potential use in high-barrier recyclable-direction structures when used carefully and within design guidelines
EVOH is a powerful packaging material when the application is correct.
What EVOH does not do
EVOH is not a universal barrier solution.
Its biggest limitation is moisture sensitivity.
EVOH contains vinyl alcohol groups, which contribute to oxygen barrier performance. These groups also make EVOH sensitive to moisture. Under high humidity or wet conditions, EVOH can absorb moisture, and its oxygen barrier performance can decrease.
This is why EVOH is often protected inside multilayer structures. Outer layers such as PE, PP, PET, or other polymers can help protect the EVOH layer from moisture exposure.
EVOH also does not automatically solve recyclability challenges.
In small amounts, EVOH may be accepted in some design-for-recycling frameworks for certain polyolefin structures, but this depends on the structure, concentration, market, recycling stream, and local guidelines. A pack containing EVOH should not automatically be called recyclable without pack-level assessment.
EVOH also does not provide every function a package needs. It does not replace the sealant layer. It does not provide all mechanical strength. It does not automatically provide puncture resistance. It does not automatically make the package retortable. It does not remove the need for testing.
EVOH must be engineered into the full structure.
PVDC: what it is and what it does
PVDC stands for polyvinylidene chloride.
PVDC is a high-barrier polymer used in packaging because it can provide strong protection against oxygen, moisture vapor, and aroma transmission. It can be used as a coating or as part of certain film structures.
PVDC has historically been used in food packaging, pharmaceutical packaging, medical packaging, and other demanding applications where both oxygen barrier and moisture barrier are important.
PVDC can be applied as a coating on substrates such as PET, BOPP, PVC, paper, or other films, depending on the application and supplier technology.
PVDC is especially useful where the packaging needs a combined barrier against gases and moisture.
Common applications may include:
• Pharmaceutical blister packaging
• Cheese packaging
• Meat packaging
• Snack packaging
• Medical packaging
• Dry foods
• Confectionery
• Aroma-sensitive products
• Moisture-sensitive products
PVDC has been important because it can deliver strong barrier performance at relatively low coating weights.
What PVDC does well
PVDC is valued for its barrier performance.
It can provide strong oxygen barrier, moisture barrier, and aroma barrier properties. This makes it useful for products where both oxygen and water vapor must be controlled.
Compared with EVOH, PVDC is generally less sensitive to humidity, which makes it useful in applications where moisture exposure is a concern.
Its main strengths include:
• Strong oxygen barrier
• Strong water vapor barrier
• Good aroma barrier
• Use as a coating on various substrates
• Useful performance at low coating weights
• Relevance in pharmaceutical, food, and medical packaging
• Transparent barrier possibilities depending on structure
PVDC can be highly effective when the product needs both oxygen and moisture protection.
What PVDC does not do
PVDC also has limitations.
One of the main issues with PVDC is end-of-life complexity and environmental concern because it is chlorine-containing. In recycling and waste systems, chlorine-containing materials can create concern depending on process conditions, waste treatment routes, and regulatory context.
Because packaging is moving toward recyclability and simpler material structures, many brands and converters are reassessing PVDC in certain flexible packaging applications.
PVDC also does not automatically make a package recyclable. As with EVOH, recyclability depends on the full pack, not one material layer or coating.
PVDC also does not replace the need for sealant layers, adhesives, print layers, or mechanical support. If it is used as a coating, the substrate and coating integrity matter. Flex cracking, coating defects, poor lamination, or aggressive processing can affect final barrier performance.
PVDC is a high-performance barrier material, but it must be used responsibly and evaluated against modern recyclability and regulatory expectations.
EVOH vs PVDC: a practical comparison
EVOH and PVDC are both used for barrier packaging, but they are not the same.
EVOH is mainly known for excellent oxygen barrier performance, especially when protected from high humidity.
PVDC is known for combined oxygen and moisture barrier performance and is less humidity-sensitive than EVOH.
EVOH is often used in coextruded structures. PVDC is often used as a coating or in specialized barrier films.
EVOH is often selected when transparent oxygen barrier is needed and the structure can protect it from moisture. PVDC may be selected when strong oxygen and moisture barrier are both required.
A simplified comparison:
EVOH: excellent oxygen barrier, moisture-sensitive, transparent, often used as a thin coextruded layer.PVDC: strong oxygen and moisture barrier, useful as a coating, historically important in food and pharmaceutical packaging, but more challenged by environmental and end-of-life concerns.
The correct choice depends on the product, structure, process, and end-of-life strategy.
For packaging teams, the better question is not:
“Which barrier material is better?”
The better question is:
“Which barrier material is right for this product, this structure, this process, this shelf life, and this recyclability target?”
Adhesives: what they do in flexible packaging
Adhesives are used to bond different layers together in laminated flexible packaging.
In a typical laminate, one film may be printed, another film may provide barrier, and another film may provide sealing. Adhesives hold these layers together so the final structure behaves as one package.
Without the right adhesive, a package may delaminate, curl, wrinkle, fail during retort, lose bond strength, or fail under product contact.
Adhesives may need to withstand:
• Heat
• Moisture
• Oil
• Acidic products
• Retort processing
• Hot fill
• Freezing
• Sterilization
• Mechanical stress
• Product migration conditions
• Storage time
There are different adhesive systems, including solvent-based, solvent-free, water-based, and reactive polyurethane systems.
The adhesive must be compatible with the films, inks, coatings, primers, product, filling conditions, and regulatory requirements.
In high-barrier packaging, adhesive selection is critical because poor adhesion can damage barrier performance or pack integrity.
What adhesives do not do
Adhesives are not usually the main oxygen barrier.
They hold the structure together, but they do not replace the functional barrier layer. In some cases, adhesive systems can influence barrier performance, but their primary job is bonding.
Adhesives also do not automatically make a structure recyclable. In fact, adhesives can affect recyclability depending on chemistry, amount, compatibility, and recycling process.
Adhesives also require curing, process control, and validation. A laminate may look acceptable immediately after lamination but may not reach final bond strength until the adhesive has cured properly.
For food packaging, adhesives must also meet relevant food-contact and migration requirements.
The wrong adhesive can turn a promising structure into a failed package.
Coatings: what they do
Coatings are thin functional layers applied to a film, paper, or other substrate.
In flexible packaging, coatings can provide or improve:
• Oxygen barrier
• Moisture barrier
• Aroma barrier
• Heat resistance
• Printability
• Surface energy
• Anti-fog properties
• Sealability
• Abrasion resistance
• Chemical resistance
• Slip or friction control
• Surface protection
Barrier coatings are especially important in modern packaging development because they can add functionality without requiring thick additional layers.
Examples may include:
• PVDC coatings
• Acrylic coatings
• PVOH coatings
• SiOx coatings
• AlOx coatings
• Heat-seal coatings
• Protective overcoats
• Primer coatings
• Special functional coatings
Coatings can help packaging teams reduce material complexity, improve performance, or develop transparent high-barrier structures.
What coatings do not do
Coatings do not work automatically.
A coating is only effective if it is applied correctly, cured correctly, protected correctly, and compatible with the rest of the structure.
Coatings can be vulnerable to:
• Cracking
• Pinholes
• Abrasion
• Poor adhesion
• Moisture sensitivity
• Thermal stress
• Flexing
• Lamination damage
• Incompatibility with inks or adhesives
A high-barrier coating may have excellent lab values on a flat film. But if it cracks during pouch forming, flexes during transport, or is damaged during conversion, the final pack may not perform as expected.
This is why pack-level testing is essential.
The coating is not the package.
The final package must be validated.
Primers: what they do
Primers are thin layers used to improve adhesion between surfaces.
In flexible packaging, primers can help inks, coatings, adhesives, or metallized layers bond to a film surface.
Many polymer films have low surface energy. This can make adhesion difficult. Primers help create a better interface between materials.
Primers may be used to:
• Improve ink adhesion
• Improve coating adhesion
• Improve adhesive bonding
• Improve metallization anchoring
• Support barrier coating performance
• Improve durability after processing
• Reduce delamination risk
A primer is often invisible to the consumer, but it can be critical to the structure.
Without the correct primer, a coating may not stay attached. Ink may rub off. Adhesive bonds may fail. Barrier layers may lose integrity.
Primers are small in thickness but large in importance.
What primers do not do
Primers are not usually designed to be the main barrier, sealant, or structural layer.
Their role is interface management.
They help materials work together.
A primer cannot compensate for a poorly selected substrate, an incompatible adhesive, or an incorrect curing process. It also cannot fix a structure that is fundamentally unsuitable for the product.
Primers must be tested as part of the total structure, especially in demanding applications such as retort, hot fill, frozen storage, aggressive products, or medical packaging.
Inks: what they do in packaging structures
Inks communicate the brand, product information, regulatory information, barcodes, batch codes, and consumer instructions.
In flexible packaging, inks can be surface-printed or reverse-printed. Reverse printing is common in laminated packaging because the ink is printed on the inside surface of an outer film and then protected by lamination.
Inks must meet several requirements:
• Color quality
• Print adhesion
• Scuff resistance
• Heat resistance
• Chemical resistance
• Migration compliance where relevant
• Compatibility with lamination adhesives
• Compatibility with primers and coatings
• Resistance to retort or sterilization where needed
• Brand consistency
• Legibility
Inks are not only decorative.
They are part of the package structure.
The ink system can affect adhesion, lamination, migration risk, recyclability, and claim communication.
What inks do not do
Inks do not usually provide the core barrier function.
They may contain pigments, binders, solvents, additives, or functional components, but the main oxygen barrier normally comes from a dedicated barrier layer or coating.
Inks also do not automatically disappear in recycling. Heavy ink coverage, dark pigments, metallic inks, carbon black, and certain ink chemistries can affect sorting, recycling quality, and recycled material appearance.
Inks can also create migration risks if the wrong system is used for the application.
This is why packaging teams must select inks based on the product, process, structure, and regulatory requirements.
A beautiful pack that fails food-contact or recyclability requirements is not successful packaging.
Why the complete structure matters more than one material
The sentence “EVOH or PVDC may provide oxygen barrier. Adhesives, coatings, primers, and inks complete the structure” captures the truth of flexible packaging.
No single material is the whole story.
A high-barrier packaging structure is a system.
• A package can fail because of a barrier issue.
• It can fail because of adhesive delamination.
• It can fail because of poor ink adhesion.
• It can fail because a coating cracks.
• It can fail because the sealant is wrong.
• It can fail because the structure is incompatible with retort.
• It can fail because the pack cannot be recycled as claimed.
Packaging teams must think in systems.
This means asking:
• What does each layer do?
• Which layer protects against oxygen?
• Which layer controls moisture?
• Which layer provides sealing?
• Which layer supports print quality?
• Which layer gives puncture resistance?
• Which layer creates recyclability complexity?
• Which layer is essential?
• Which layer can be changed?
• Which claims can be supported?
This approach turns packaging development from material selection into structure design.
The move toward recyclable high-barrier packaging
The packaging industry is under pressure to reduce waste and improve recyclability.
In Europe, the Packaging and Packaging Waste Regulation is pushing the market toward packaging that is recyclable by design and better aligned with circular economy objectives.
This creates a major challenge for high-barrier flexible packaging.
Many traditional high-barrier structures rely on combinations of PET, aluminum foil, nylon, PE, PP, EVOH, PVDC, adhesives, coatings, and inks. These combinations may perform well but can create end-of-life complexity.
The industry is now exploring:
• Mono-material packaging
• Mono-PP packaging
• Mono-PE packaging
• Transparent high-barrier films
• Aluminum foil alternatives
• PVDC alternatives
• Downgauging
• Advanced coatings
• Vapor-deposited barrier films
• Recyclability-compatible adhesives and inks
• Pack-level recyclability assessment
The goal is not to remove performance.
The goal is to preserve performance while reducing unnecessary complexity.
Practical example: replacing a complex snack laminate
Imagine a snack pack that uses a PET/metallized film/PE structure.
The pack protects crispness and aroma, runs well on machines, and looks good on shelf. But it may not support a clear mono-material recycling pathway.
A packaging development team may explore a PE-based or PP-based structure with a high-barrier coating.
The team must ask:
• Can the new structure maintain moisture barrier?
• Can it protect aroma?
• Can it keep the snack crisp?
• Can it run at the same speed?
• Can it seal correctly?
• Will the ink system survive handling?
• Will the barrier coating crack?
• Can the pack support recyclability direction?
• Can the claim be documented?
This is where the full structure matters.
The barrier layer is only one part of the answer.
Practical example: ready meals, sauces, and soups
Ready meals, sauces, and soups can be demanding because they may require hot fill, pasteurization, retort, or microwave performance.
The structure must withstand heat, moisture, product chemistry, sealing stress, and distribution.
If EVOH is used, moisture and heat exposure must be considered carefully. If PVDC is used, recyclability and end-of-life concerns may need review. If a coated barrier film is used, the coating must survive processing and pouch forming.
Adhesives must withstand the process. Inks must not migrate or break down. Primers must anchor the coatings. Sealants must maintain integrity.
For these categories, packaging cannot be chosen from a datasheet alone.
The final structure must be tested with the real product and process.
Practical example: medical packaging
Medical packaging requires high confidence.
The package may need barrier, cleanliness, sterilization compatibility, seal integrity, and documentation.
In this context, every material must be controlled.
• The barrier layer protects the product.
• The adhesive supports structural integrity.
• The primer supports adhesion.
• The ink must remain stable and compliant.
• The coating must survive sterilization or handling.
• The sealant must close reliably.
A material change in medical packaging can require significant validation.
This is why credible technical documentation is essential.
How packaging teams should evaluate EVOH, PVDC, adhesives, coatings, primers and inks
A strong evaluation process should include the following steps.
Step 1: Define the product risk
Is the product oxygen-sensitive, moisture-sensitive, aroma-sensitive, light-sensitive, heat-sensitive, or contamination-sensitive?
Step 2: Define the process
Will the product be dry-filled, hot-filled, pasteurized, retorted, frozen, sterilized, or shipped long distance?
Step 3: Define the shelf-life target
How long must the product remain safe and acceptable?
Step 4: Define barrier requirements
What OTR and WVTR values are required?
Step 5: Map each layer
What does each layer do? Which layers are essential?
Step 6: Check interface compatibility
Do inks, primers, coatings, and adhesives work together?
Step 7: Test the structure
Laboratory testing, conversion trials, filling trials, shelf-life tests, and distribution tests are all important.
Step 8: Assess recyclability direction
Does the full pack support the intended recycling pathway?
Step 9: Document claims
Can the sustainability, barrier, or recyclability claim be supported?
Step 10: Review commercial feasibility
Can the structure be produced reliably at scale?
This is how packaging development becomes responsible and evidence-based.
What beginners should remember
For someone new to packaging, the most important lesson is simple:
A package is not just plastic.
It is an engineered structure.
EVOH and PVDC may provide oxygen barrier. Adhesives bond layers. Coatings add function. Primers help materials stick. Inks communicate and must remain compatible. Sealant layers close the pack.
Every layer has a job.
When one layer changes, the whole structure may be affected.
What experts should remember
For experts, the challenge is more strategic.
The industry is moving toward recyclable flexible packaging, mono-material structures, PPWR readiness, ESG reporting, and credible sustainability claims.
That means the traditional material toolbox must be reassessed.
EVOH and PVDC still matter, but their use must be evaluated in the context of humidity, recyclability, coating stability, regulatory direction, product protection, and pack-level performance.
Adhesives, coatings, primers, and inks must no longer be treated as secondary details.
They are part of the performance system and part of the recyclability conversation.
The future belongs to structures that can be:
• Tested
• Documented
• Validated
• Explained
• Recycled where systems allow
• Commercially scaled
• Scientifically defended
That is what expert packaging development now requires.
Now we know high-barrier packaging is a system, not a single material
EVOH and PVDC can provide oxygen barrier and help protect sensitive products.
But they are only part of the structure.
Adhesives, coatings, primers, inks, substrates, sealants, tie layers, and processing conditions all influence the final package.
This is why packaging teams must stop thinking only in terms of individual materials and start thinking in complete structures.
The right question is not:
“Which barrier material should we use?”
The question that separates theory from performance is:
“What complete packaging structure will protect the product, perform on the line, support shelf life, meet regulatory requirements, and align with our recyclability and sustainability goals?”
That is the question that separates basic material selection from advanced packaging development.
Ready to talk about clear material information.
If your team is reviewing high-barrier flexible packaging, EVOH or PVDC alternatives, mono-material packaging, Mono-PP or Mono-PE structures, aluminum foil replacement, advanced coatings, GL BARRIER film options, or PPWR-ready packaging development, TOPPAN Films can support the technical conversation.
Read the full article here:https://films.toppan.com/blog/evoh-pvdc-high-barrier-flexible-packaging-structures
For technical discussions, datasheets, samples, or application-specific packaging development, contact TOPPAN Packaging Czech s.r.o.: Contact us at: toppancz@toppan.com
Do not evaluate barrier performance in isolation; build the packaging structure around the product, validate performance with data, and support every packaging claim with clear material information.
Speak with TOPPAN Packaging Czech s.r.o. about barrier-film options, OTR and WVTR targets, samples, datasheets, application-specific testing, and recyclable high-barrier packaging development.
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