Does Thicker Packaging Film Protect Food Better?

When choosing flexible packaging for food products, increasing film thickness may seem like a straightforward way to improve protection. A thicker package can feel stronger, resist certain forms of mechanical damage, and provide a longer path for gases and moisture to travel through the material.

However, thicker packaging film does not automatically provide better food protection. Its performance depends on the polymer materials used, the structure of the film, the properties of the food, and the conditions under which the product is packaged and stored.

For example, a multilayer film containing a dedicated oxygen-barrier layer may protect oxidation-sensitive food more effectively than a thicker film made from a single material with relatively high oxygen permeability. Similarly, a film with excellent barrier properties can still allow moisture or oxygen to enter through an imperfect heat seal.

For food manufacturers, selecting the right packaging film means understanding what needs to be protected, which barrier properties matter most, and how the material will perform on the packaging line.

This guide explains the relationship between packaging film thickness, barrier properties, and food shelf life, with practical considerations for selecting roll film for automatic packaging machines.

1. What Does Packaging Film Thickness Actually Tell You?

Film thickness is an important packaging specification, but it describes only one aspect of the material.

Thickness is commonly expressed in micrometers (µm). It affects several properties, including stiffness, puncture resistance, mechanical strength, and the rate at which gases or vapors pass through a film.

For the same homogeneous material, increasing thickness generally reduces the transmission rate of oxygen or water vapor when other relevant conditions remain unchanged. This is because molecules must travel through a longer material path.

However, thickness alone does not tell you how easily a particular gas or vapor can pass through the material.

Thickness and permeability are different measurements

Two terms are particularly useful when evaluating packaging films:

• Permeability describes the intrinsic ability of a material to allow a particular substance, such as oxygen or water vapor, to pass through it under defined conditions.

• Transmission rate describes how much of that substance passes through a specific film area over a given period under specified test conditions. The measured film thickness is already part of the result.

For oxygen, the commonly used measurement is the Oxygen Transmission Rate (OTR). For moisture, it is the Water Vapor Transmission Rate (WVTR).

Lower OTR generally means better oxygen barrier performance, while lower WVTR generally means better water vapor barrier performance, provided the test conditions are comparable.

Consider two hypothetical packaging films:

• Film A is a relatively thick single-layer polyethylene film.

• Film B is a thinner multilayer laminate containing an appropriate oxygen-barrier material.

If Film B has a lower measured OTR under the same test conditions, it provides better oxygen barrier performance despite being thinner.

This is possible because the materials and layer structure influence permeability, not just the total thickness. Temperature, relative humidity, and the specific test method must also be considered when comparing results.

For procurement teams, comparing films by thickness alone can therefore lead to the wrong material choice.

2. Oxygen Barrier: Protecting Food from Oxidation

Oxygen is one of the major factors affecting the quality of many packaged foods. Depending on the product, oxygen exposure can contribute to rancidity, color changes, flavor deterioration, and the degradation of sensitive nutrients.

Foods containing unsaturated fats, such as nuts, seeds, and some snack products, can be particularly susceptible to lipid oxidation. Coffee and other aroma-sensitive products may also experience flavor changes during storage.

For these products, oxygen barrier performance can be an important part of the packaging specification.

Why a thicker film may not be enough

A thicker film made from the same material will generally reduce oxygen transmission if the structure and test conditions remain comparable. Nevertheless, the improvement may not be sufficient for a product with demanding oxygen-barrier requirements.

Material selection can have a greater effect than simply adding thickness.

Common packaging structures use different materials to perform different functions:

• PET (polyethylene terephthalate): Often provides stiffness, dimensional stability, and a printable outer surface.

• PE (polyethylene): Commonly provides moisture resistance and a heat-sealable inner layer.

• PA (polyamide): Can contribute toughness and puncture resistance, depending on the grade and structure.

• EVOH (ethylene vinyl alcohol): Can provide excellent oxygen barrier performance when its formulation and surrounding layers are appropriate for the intended humidity conditions.

• Aluminum foil: Can provide a very high barrier to oxygen, moisture, and light when incorporated into a properly designed laminate.

These materials are not interchangeable, and their performance depends on the complete packaging structure. For example, EVOH is sensitive to moisture, so surrounding layers help protect its barrier performance in practical applications.

A multilayer film can combine the strengths of different materials without requiring the entire film to be made from the same high-barrier polymer.

Which foods need particular attention to oxygen?

Coffee, nuts, roasted seeds, powdered milk, and fat-containing snack products are examples of foods for which oxygen exposure may affect quality.

However, the required barrier level varies by product. Roasted coffee beans, for instance, have different packaging considerations from instant coffee powder, while nuts with high unsaturated fat content may need particular attention to oxidative stability.

The appropriate specification should be established using product characteristics, intended shelf life, packaging atmosphere, and storage conditions.

3. Water Vapor Barrier: Preventing Moisture Gain and Loss

Oxygen is not the only substance that can pass through packaging film. Water vapor can also move across the package wall when a difference in water vapor pressure exists between the inside and outside environments.

For many dry foods, moisture control is essential to maintaining texture, flowability, and product quality.

When moisture enters the package

Products such as crackers, potato chips, powdered seasonings, and dry cereal can absorb moisture during storage.

Depending on the formulation, moisture uptake may cause:

• Loss of crispness in snacks and crackers.

• Caking or reduced flowability in powdered products.

• Changes in texture or physical stability.

• Conditions that may increase the risk of deterioration in moisture-sensitive foods.

A thicker film can help reduce moisture transmission when the material structure remains the same. But a thicker film is not necessarily the most effective option if its water vapor barrier performance is inadequate for the intended application.

For example, PE often provides good moisture resistance, but its oxygen barrier is relatively limited compared with dedicated oxygen-barrier materials. This is one reason PE is frequently combined with other polymers in flexible food packaging.

When moisture loss is the problem

The opposite situation also matters.

Some products need to retain moisture rather than prevent moisture from entering. Certain baked goods, soft confectionery, and other moisture-sensitive products may lose water during storage, resulting in undesirable changes in texture.

The packaging target therefore depends on the product. A suitable material must control moisture transfer in the direction that matters for the intended application.

When comparing film specifications, manufacturers should review WVTR values under relevant temperature and humidity conditions rather than assuming that greater thickness guarantees sufficient protection.

4. Light and Aroma: Two More Factors Affecting Food Quality

Oxygen and water vapor receive considerable attention in packaging design, but they are not the only factors affecting food shelf life.

Light protection

Light exposure can accelerate certain degradation reactions, including oxidation of susceptible food components. Its effect depends on the food composition, the wavelength and intensity of the light, and the duration of exposure.

A thicker transparent film does not necessarily provide better light protection than a thinner one.

When light sensitivity is important, manufacturers may consider opaque, printed, metallized, or foil-containing structures. The appropriate choice depends on the required degree of light protection, appearance, and other packaging requirements.

For example, a product that deteriorates under prolonged light exposure may benefit more from a suitable opaque or light-blocking structure than from simply increasing the thickness of a transparent film.

Aroma retention

Aroma compounds can also migrate through certain packaging materials. Some compounds may be lost from the food, while external odors can sometimes migrate into the package.

The extent of aroma loss depends on the chemical properties of the aroma compounds and their interaction with the packaging material.

For coffee, spices, and other aroma-sensitive foods, the material's resistance to aroma transmission may be an important consideration alongside oxygen barrier performance.

A film that performs well against oxygen is not automatically the best choice for every aroma compound. Material selection should reflect the specific product and its quality requirements.

5. Why Multilayer Film Structure Matters More Than Thickness Alone

Many flexible food packages use multilayer structures because one material rarely provides the ideal combination of barrier performance, strength, printability, and heat-sealing properties.

A typical laminate may combine an outer layer for mechanical support and printing, a barrier layer for controlling gas or moisture transmission, and an inner sealant layer that forms the package seal.

The exact arrangement varies by application.

For example, a PET/PE laminate may provide a useful combination of printability, mechanical properties, and moisture resistance, but it does not automatically deliver the same oxygen barrier as a structure incorporating a dedicated barrier layer.

For more demanding applications, a manufacturer may consider structures containing EVOH, metallized film, or aluminum foil, depending on the required protection and processing conditions.

Example: Choosing film for three food products

Coffee beans

The main concerns may include oxygen exposure, aroma retention, light protection, and package integrity. Depending on the product and desired shelf life, the packaging system may also require a degassing valve or another method of managing carbon dioxide released by freshly roasted beans.

Potato chips

Moisture protection helps maintain crispness, while oxygen control can help limit oxidative deterioration. The film also needs suitable mechanical properties to withstand handling and distribution.

Powdered seasoning

Moisture ingress may cause caking, while oxygen or light sensitivity depends on the ingredients. The film must also provide reliable seals around the powder, which can contaminate the sealing area during filling.

These examples illustrate why packaging film should be selected according to the food's principal deterioration mechanisms rather than a general preference for thicker material.

A suitable structure balances the required barrier properties with mechanical performance, food-contact requirements, cost, and compatibility with the packaging process.

6. Packaging Film Barrier Performance Depends on Storage Conditions

Film specifications are meaningful only when their test conditions are understood.

Temperature and relative humidity can influence the transmission of gases and water vapor through packaging materials. Some barrier polymers are particularly sensitive to moisture, and higher temperatures can increase molecular mobility and transmission rates.

As a result, a film tested under one set of laboratory conditions may perform differently in a warmer or more humid distribution environment.

Food characteristics also matter. The same packaging structure may be suitable for one product but inadequate for another because their sensitivity to oxygen, moisture, or light differs.

Before finalizing a material, manufacturers should consider:

• The product's fat content, moisture sensitivity, aroma profile, and other relevant characteristics.

• The intended shelf life and acceptable quality changes.

• The expected storage and transportation temperatures.

• The relative humidity and potential exposure to light.

• Whether the package contains air, vacuum, or a modified atmosphere.

• The required barrier performance under realistic use conditions.

Barrier testing and shelf-life validation are not the same thing

OTR and WVTR testing helps characterize the packaging material, but it does not independently establish the shelf life of the finished food.

Shelf-life validation should consider the food itself, the complete package, the filling and sealing process, and the intended storage conditions. Depending on the product, this may involve sensory evaluation, moisture measurement, oxidation indicators, microbiological testing, or other product-specific assessments.

This distinction is particularly important when changing from one film structure to another. A lower laboratory OTR may be beneficial, but the manufacturer still needs to verify that the complete packaging system meets the product's shelf-life requirements.

7. How Heat-Sealing Quality Affects Food Protection

Even a high-barrier film cannot protect food effectively if the finished package has a leaking seal.

The package wall and the seals form part of the same protective system. Oxygen and moisture may enter through a defective seal or other package damage even when transmission through the film itself is low.

Potential causes include insufficient or excessive sealing temperature, unsuitable sealing pressure or dwell time, contaminated seal areas, wrinkles, and incompatible material layers.

The appropriate sealing conditions depend on the film structure and the packaging machine.

For powder products, particles trapped between the sealing surfaces can interfere with seal formation. For products containing oil or liquid, contamination may similarly affect the seal, depending on the formulation and process.

Film thickness can also influence machine setup. A change in thickness or laminate structure may affect heat transfer, sealing behavior, web handling, and the settings required to achieve a consistent seal.

For this reason, switching to a thicker film should not be treated as a simple material substitution without checking its performance on the packaging line.

What should manufacturers verify?

When introducing a new packaging film, manufacturers should check:

1. Seal strength: Whether the seal meets the application's mechanical requirements.

2. Seal integrity: Whether the finished package has leaks or channels that compromise protection.

3. Machine compatibility: Whether the film runs consistently at the required production speed.

4. Package consistency: Whether wrinkles, misalignment, or product contamination affect the finished seals.

5. Performance after handling: Whether the package maintains its integrity during transport and distribution.

Seal strength and leak testing measure different aspects of performance, so one should not automatically be used as a substitute for the other.

The specific test methods and acceptance criteria should reflect the food product, package format, and applicable quality requirements.

8. Selecting Roll Film for Automatic Food Packaging Machines

For food manufacturers using automatic packaging equipment, material selection must consider both product protection and machine performance.

A film with excellent barrier properties is not necessarily suitable for every packaging machine. Its dimensions, layer arrangement, coefficient of friction, mechanical behavior, and heat-sealing characteristics must also match the intended equipment and package format.

For vertical form fill seal (VFFS) machines, roll film is formed into a tube, filled with product, and sealed to create individual packages. The film must therefore be compatible with forming, longitudinal sealing, transverse sealing, and the required bag dimensions.

Key factors to check before choosing roll film

1. Required barrier performance

Identify whether oxygen, water vapor, light, or aroma retention is the primary concern. Request the relevant OTR and WVTR data, including the test temperature and humidity conditions.

2. Film structure and thickness

Confirm the complete layer structure rather than relying on total thickness alone. If the supplier provides only a thickness specification, request additional information about the material and its barrier properties.

3. Heat-sealing characteristics

Check that the inner sealant layer is compatible with the packaging machine and the intended operating conditions. Validate the sealing window rather than assuming that a similar film will use identical settings.

4. Roll dimensions and forming compatibility

Confirm film width, roll dimensions, bag size, and other relevant specifications against the machine configuration. The film should track and form consistently at the required production speed.

5. Finished-package testing

Run production trials using the actual food product and proposed film. Inspect seal quality, package appearance, and machine stability, then validate barrier and shelf-life performance as required.

The objective is not to select the thickest available film. It is to identify a material that provides adequate protection while running reliably on the packaging line.

9. Does Better Food Protection Always Require More Packaging Material?

Not necessarily.

Increasing film thickness can improve certain mechanical and barrier properties, but it also increases material consumption when the film area and composition remain unchanged. It may also affect material cost and packaging-machine settings.

A carefully engineered multilayer structure may achieve the required barrier performance with less material than a thicker, less suitable structure. Whether this is possible depends on the food, the existing material, and the required performance.

However, reducing thickness without validation can also create problems, including inadequate mechanical strength, unstable film feeding, or unreliable sealing.

A practical approach is to establish the minimum performance requirements first and then compare material options against those requirements.

This evaluation should include barrier performance, seal integrity, machine efficiency, package damage rates, material consumption, and the shelf life of the finished food.

The best material choice is the one that meets the product's protection requirements consistently under actual production and distribution conditions—not simply the one with the greatest thickness or the lowest material cost.

Conclusion: Choose Packaging Film by Performance, Not Thickness Alone

Thicker packaging film can provide advantages, and increasing thickness generally reduces the transmission rate of gases or moisture when the material and other relevant conditions remain the same. However, thickness is only one part of packaging performance.

Material composition and multilayer structure determine much of a film's resistance to oxygen, water vapor, and aroma compounds. Light protection requires separate consideration, while temperature, humidity, package integrity, and storage conditions all influence the final result.

For food manufacturers, a reliable packaging decision begins with the product's specific preservation requirements. The next steps are to compare relevant barrier data, select a suitable film structure, confirm compatibility with the packaging machine, and validate the finished package.

At Keypack Intelligent Technology, packaging film selection and machine compatibility are important considerations when developing automatic food packaging solutions. If you are planning to change your roll film or improve packaging consistency, evaluating the material together with the forming and sealing process can help identify a practical solution for your production requirements.

Contact Keypack to discuss your food packaging application, roll film specifications, and automatic packaging machine requirements.

Website: https://shkpack.com/

Frequently Asked Questions

Does thicker plastic film always have a lower oxygen transmission rate?

No. For the same material structure under comparable test conditions, greater thickness generally lowers the oxygen transmission rate. However, a thinner film made with a suitable high-barrier layer may outperform a thicker film made from a less effective material.

What is the difference between OTR and WVTR?

OTR measures the rate at which oxygen passes through a film under specified test conditions. WVTR measures the rate at which water vapor passes through it. Both are useful for comparing packaging materials, but their values must be interpreted using the relevant test conditions.

Which packaging film is best for moisture-sensitive food?

The appropriate film depends on the food, the required shelf life, and the storage environment. Materials with suitable water vapor barrier properties are important for products that must remain dry, but oxygen, light, mechanical strength, and sealing requirements may also affect the final selection.

Can high-barrier film extend food shelf life?

It can help when oxygen or moisture transmission is a limiting factor in product deterioration. However, shelf life also depends on the food's initial quality, processing, hygiene, package integrity, storage temperature, and other product-specific factors. The finished packaging system should be validated.

Does a high-barrier film work with every VFFS packaging machine?

No. The film must be compatible with the machine's forming and sealing systems, roll dimensions, required bag format, and operating speed. Material trials are recommended when changing film structures or thicknesses.

Further Reading

• Multilayers of Renewable Nanostructured Materials with High Oxygen and Water Vapor Barriers for Food Packaging

• Food Packaging Permeability Behaviour: A Report

• A Quantitative Approach to Assess the Contribution of Seals to the Permeability of Water Vapour and Oxygen in Thermosealed Packages