วิธีระบุม้วนแผ่น PET/EVOH สำหรับการใช้งานถาด MAP

01 Understanding Sheet Requirements for MAP Applications

Modified atmosphere packaging (MAP) is commonly used for fresh meat, poultry, seafood and other foods that require controlled packaging conditions. For manufacturers of thermoformed MAP trays, selecting an appropriate sheet structure is an important part of meeting the packaging specification.

Standard PET sheet provides useful stiffness, surface appearance and thermoforming properties. However, PET alone may not provide the oxygen-barrier performance required for a particular MAP application.

PET/EVOH multilayer sheet combines PET-based structural properties with an EVOH functional barrier layer. The resulting material can be specified for applications where oxygen transmission must be controlled.

DESU supplies PET/EVOH high-barrier sheet in roll form for thermoforming manufacturers and packaging converters. The sheet specification should be selected according to the customer’s barrier requirements, processing conditions and intended packaging structure.

02 Comparing PET/EVOH/PE and PET/EVOH/PET Sheet

DESU offers two PET/EVOH multilayer sheet structures: PET/EVOH/PE and PET/EVOH/PET. Both incorporate an EVOH barrier layer, but their outer surface materials differ. This difference matters when specifying the sheet for the intended packaging application.

The choice is not simply a question of which structure has the better oxygen barrier. Both can be designed around a barrier requirement, while their surface characteristics and compatibility with other packaging materials may differ.

For PET/EVOH/PE sheet, the PE side should be clearly identified in the specification. For PET/EVOH/PET sheet, the required surface and sealing arrangement should also be confirmed before ordering.

Additional structure details, including individual layer proportions and functional interfaces, should be agreed according to the application rather than assumed from the abbreviated structure name.

See DESU’s แผ่นพลาสติก Evoh overview for related product information.

03 Defining Oxygen-Barrier Requirements

Oxygen-barrier performance is one of the main reasons for specifying PET/EVOH sheet. EVOH is widely used in multilayer packaging because of its oxygen-barrier characteristics under suitable conditions.

However, the presence of an EVOH layer does not automatically establish a particular oxygen transmission rate (OTR). Barrier performance depends on the complete structure, the effective barrier-layer thickness and the conditions under which the material is evaluated.

Define the Required Barrier Level

Buyers should communicate their target oxygen-barrier requirement whenever available. This may be expressed through an OTR specification, an approved reference material or another agreed technical requirement.

OTR values should be compared only when the relevant testing conditions are understood. Temperature, relative humidity and specimen condition can influence the reported result.

Consider Humidity Exposure

EVOH oxygen-barrier performance is sensitive to moisture. The surrounding layers and the intended storage environment therefore matter when selecting a multilayer sheet structure.

For applications involving high humidity or moisture exposure, the buyer should discuss the expected conditions with the sheet supplier rather than relying on a general high-barrier description.

Account for Forming Requirements

During thermoforming, the sheet stretches to form the required shape. The original flat-sheet thickness and layer distribution can change, particularly in deeper or more demanding areas.

For this reason, a flat-sheet barrier specification should not be treated as a guarantee of identical performance in every formed area. The buyer should identify any application-specific performance requirements that need to be confirmed after conversion.

04 Sheet Quality Factors Beyond Oxygen Barrier

Oxygen-barrier properties are essential, but they are not the only requirements for a reliable multilayer thermoforming sheet. Consistent sheet quality also affects material handling and processing.

For repeat orders, buyers should also consider batch-to-batch consistency. A material approved during an initial trial should be supplied against an agreed specification so that subsequent orders can be evaluated on the same basis.

05 How to Select the Right PET/EVOH Sheet Structure

A practical selection process begins with the application’s functional requirements rather than choosing a multilayer structure by name alone.

1. Identify the Application

Specify the intended MAP application, such as fresh meat, poultry or seafood packaging. Different applications may involve different oxygen-barrier, storage and material-contact requirements.

2. Confirm the Surface Requirement

Determine whether the project calls for a PE-side surface or PET surfaces. This should be considered together with the intended lidding material and other relevant packaging interfaces.

3. Establish the Sheet Thickness

Sheet gauge should reflect the intended forming geometry, required rigidity and existing equipment conditions. There is no single thickness that automatically suits every MAP tray application.

4. Specify the Barrier Requirement

Provide the required oxygen-barrier target or an approved reference specification when available. The measurement conditions should be included wherever possible.

5. Confirm Material Compatibility

Review the multilayer sheet’s processing suitability, contact-side requirements and any application-specific compliance documentation needed for the destination market.

06 Specifying PET/EVOH Sheet in Roll Form

For thermoforming manufacturers, the roll format is part of the material specification. Even a suitable multilayer sheet may create unnecessary processing difficulties if its roll dimensions or winding configuration do not match the line.

The following details should be confirmed before placing an order:

• Sheet width: Match the production web and material layout.
• Total thickness: Specify the nominal gauge and agreed tolerance.
• Core diameter: Confirm compatibility with the unwinding equipment.
• Roll diameter or weight: Define handling and machine limits.
• Winding configuration: Confirm the required roll orientation.
• Surface identification: Clearly distinguish the relevant material sides.
• Packaging and storage: Discuss protection from contamination, damage and unsuitable storage conditions.

For asymmetric structures such as PET/EVOH/PE, surface identification is especially important. The PE side and PET side should be specified consistently in the purchase documentation and roll identification.

07 What to Include in a PET/EVOH Sheet RFQ

A clear inquiry helps the supplier understand which material requirements are already fixed and which need further technical discussion. If the buyer currently uses an approved multilayer sheet, its existing specification can provide a useful starting point.

DESU supplies PET-based multilayer thermoforming sheet rolls for packaging manufacturers and converters. We can discuss the required structure, sheet format and material specification based on your application information.

For related products, see แผ่นพลาสติก Evoh และ สัตว์เลี้ยงสำหรับบรรจุภัณฑ์บรรยากาศที่ดัดแปลง -

Need to source PET/EVOH sheet rolls? ติดต่อ DESU with your material requirements for further discussion.

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