High-Barrier Polymer Resins & Tie-Layer Materials
Define barrier and adhesion requirements for multilayer packaging. Compare resin functions, process compatibility, OTR/WVTR evidence and supplier qualification.
General technical information published by PAXOMER Inc. to support preliminary material evaluation. It is compiled from the sources cited on this page and has not been independently reviewed or certified by a professional engineer, laboratory or certification body. Values marked typical, illustrative or requiring confirmation are not specifications. Confirm properties, standard editions, regulatory status and suitability for your specific application with the manufacturer and, where the use is regulated or safety-related, with a qualified professional or the relevant authority.
1. Quick answer
A barrier resin controls a defined transmission pathway; a tie layer bonds specified neighboring materials. Select the complete structure and process together, then test barrier, adhesion and finished-package performance under agreed conditions. Do not treat resin-family names as a finished-package specification.
2. Which product and protection requirement are being specified?
Start with the packed product, intended shelf life or protection objective, package format, processing sequence and distribution/storage conditions. Ask what mechanism matters: oxygen, moisture, aroma, another permeant or loss of package integrity. A purchasing brief should identify how the target was established. Do not turn a generic statement such as “high barrier” into an unsupported shelf-life promise.
3. What is the distinction between a barrier layer and a tie layer?
Kuraray describes EVOH as a gas-barrier polymer. LyondellBasell describes its tie-layer resins as modified polyolefins for bonding dissimilar polymers in multilayer structures. [B1, B2] These functions are distinct. Ask the resin supplier to recommend the actual grade for the adjacent materials, process and exposure conditions rather than selecting on terminology alone. The cited manufacturers are technical references; no commercial relationship with PAXOMER is asserted.
4. What should a complete layer specification contain?
- Item: Finished format; What the buyer should define: Film, sheet, container or other article; Why the evidence is needed: Connects resin selection with the product
- Item: Layer sequence; What the buyer should define: Outside-to-inside order and material identities; Why the evidence is needed: Identifies interfaces and functional roles
- Item: Dimensions; What the buyer should define: Total gauge and individual-layer targets/tolerances; Why the evidence is needed: Makes structure and cost comparisons meaningful
- Item: Barrier; What the buyer should define: Target permeant, units, method and test conditions; Why the evidence is needed: Defines the claimed performance
- Item: Adhesion; What the buyer should define: Interface, preparation, conditioning and acceptance; Why the evidence is needed: Defines the bonding decision
- Item: Processing; What the buyer should define: Equipment, temperature window and throughput constraints; Why the evidence is needed: Supports grade/process compatibility review
- Item: End use; What the buyer should define: Contact conditions, thermal treatment and distribution; Why the evidence is needed: Defines the final qualification environment
All values must be supplied or developed through the application review. This table does not supply universal thicknesses or barrier targets.
5. How should coextrusion compatibility be reviewed?
Give the supplier the complete structure, processing equipment, throughput and relevant melt conditions. Ask how the proposed grades should be matched and processed. LyondellBasell's technical introduction discusses viscosity matching and notes that matching melt index alone may not resolve layer-flow instability. [B3] Do not infer that identical melt-flow numbers establish interchangeability. Review the actual grade pairings and preserve the trial's machine and layer-distribution records.
6. How should oxygen and moisture performance be compared?
Compare results only with their stated units, temperature, humidity/conditioning, specimen and method. ASTM D3985 addresses oxygen transmission through film/sheet using a coulometric sensor; ASTM F1249 addresses water-vapor transmission through film/sheet using a modulated infrared sensor. [B4, B5] A resin data point, flat-film result and completed package are different test objects. Ask a competent laboratory which approach answers the purchasing question and how seals, closures and forming are addressed.
7. What should a qualification trial demonstrate?
Agree on the reference structure and candidate, specimen traceability, layer dimensions, process stability, appearance, adhesion and barrier criteria. Include the actual downstream route, such as forming or sealing, when relevant. Preserve representative material and document deviations. Compare completed packaging where that is the real product; a good flat-film result does not by itself close a package-performance decision. The complete test program requires application-specific review.
8. How can buyers investigate delamination or unstable layers?
Identify the interface and whether the observation changes with conditioning, downstream processing or storage. Record where and how the sample was obtained. Review material identity, layer distribution, actual processing history and test preparation with the suppliers. Consider multiple explanations and isolate changes experimentally. Avoid declaring a tie resin defective solely from a failed package with an unidentified failure interface.
9. When should an alternative construction be evaluated?
Compare candidate resin/structure changes against the actual protection requirement, process capability, converting performance, documentation and commercial format. A foil-containing or metallized structure is a separate comparison requiring its own evidence, not an automatically equivalent substitute. A simplified structure should still meet the intended package's performance requirements. Recyclability claims require an applicable assessment of the complete article and collection/recycling context; this guide establishes none.
10. What documentation and commercial details belong in the inquiry?
Request grade-specific technical and safety documentation, intended-use information, traceability and change control. Ask for the proposed sample form, supply format, quotation basis, order quantity and lead time. Confirm which entity makes and sells each resin, and whether a distributor or compounder changes the offered product. No stock, food-contact suitability or manufacturer appointment is established here. Related flexible-packaging, adhesive and laboratory-testing resources can help frame the complete qualification programme.
11. What questions help prevent an unsuitable substitution?
The buyer questions and their complete answers are in the FAQ collection below.
12. What should a barrier-resin inquiry contain?
Provide email, packed product or industrial use, complete proposed layer sequence, process, total and individual-layer requirements, adjacent polymers, target barrier property with conditions, adhesion requirement and downstream operations. Identify the commercial form requested and the decision that a sample or laboratory program must support.
13. Which related guidance can help the decision?
Related reading: Reading a technical datasheet (/knowledge/understanding-datasheets). A practical guide to polymer selection (/knowledge/polymer-selection).
14. Which sources support this guide?
[B1] Kuraray EVOH overview: https://www.kuraray.com/eu-en/products/eval/ (opens in a new tab)
15. Specify barrier under humidity and processing conditions
A barrier polymer and a tie-layer resin have different jobs. The barrier layer limits transport of selected species; a tie layer helps compatible interfaces form within a multilayer construction. Layer order, thickness distribution, processing and conditioning influence the complete result. Naming EVOH or a tie-layer chemistry does not establish package shelf life.
Specify transmission data with species, units, temperature, relative-humidity conditions and specimen construction. Some barrier materials respond strongly to moisture exposure. Do not compare dry and humid results as if they represent the same service condition. Also assess mechanical and thermal damage introduced during forming, flexing and sealing.
For a material change, confirm the actual coextrusion or lamination interface and processing compatibility with the responsible manufacturer. Delamination can arise from contamination, insufficient compatible interface formation or process history. Product-contact documentation and recycling assessment concern the complete construction. This page provides no guaranteed permeability or universal extrusion recipe.
16. How should production problems be investigated?
Use the observations below to structure an investigation. They identify possible mechanisms, not a diagnosis from appearance alone. Compare candidate and control under the same defined conditions.
| Observed issue or decision | What to check | Qualification implication |
|---|---|---|
| Barrier results differ between laboratories | Humidity, temperature, units and specimen construction | Normalize conditions before ranking structures |
| Delamination at a barrier interface | Layer identity, compatibility, contamination and process history | Evaluate the actual multilayer interface |
| Flat web passes; formed pack fails | Thinning, flex damage, seals and package geometry | Test the converted package |
17. Which sources support the guidance, and what are their limits?
These references support the named material or test scope. They do not establish supplier representation, a complete claim audit or a PAXOMER product approval.
https://www.proampac.com/en-us/rollstock/ (opens in a new tab)
18. Transmission rate, permeability and formed-package performance differ
An oxygen transmission rate describes transport through the tested specimen per area and time under stated conditions. Permeability coefficients additionally incorporate a thickness and driving-force basis under the applicable model. Do not compare the two as the same quantity or multiply a multilayer result by total gauge without checking the method and structure. Retain permeant, units, temperature, humidity on the relevant sides and conditioning with every result.
Barrier layers and tie layers serve different primary functions. EVOH can provide a gas-barrier function; a compatible modified-polyolefin tie resin can bond dissimilar layers. The required grade depends on adjacent materials and processing. Equal melt-flow index measured at a single condition does not establish matched rheology during coextrusion. Compare actual layer stability, distribution, adhesion and downstream performance on the line.
Forming, flexing, thermal treatment and sealing can alter the complete package. Evaluate the lowest relevant local barrier-layer thickness or damage location rather than relying only on average flat-web gauge. A good film transmission result cannot rule out a seal or closure leak. Product-contact documentation and recycling claims require their own complete-article assessment; no shelf-life, contact-compliance or recyclability guarantee follows from naming EVOH or a tie resin.
19. Barrier qualification: identify the test object and mechanism
| Evidence | Report | Separate remaining question |
|---|---|---|
| Resin | Exact grade and property method/condition | Performance of a converted multilayer |
| Flat film | Layer construction, permeant, rate units and humidity | Forming and flex damage |
| Formed package | Geometry, local thinning, seals and exposure | Product-specific shelf-life validation |
| Interface | Adjacent layers, preparation and aged failure location | Suitability of all other layers |
Primary reference for the indicated technology or test scope; the acceptance record above is an application-planning aid, not a reproduced standard procedure or a reported PAXOMER test result.
LyondellBasell: tie-layer resin function (opens in a new tab)
20. Which evidence separates a barrier-resin qualification from a packaging claim?
Require the layer construction and barrier conditions with each result. Evaluate formed and sealed packs in addition to flat film when the application changes local thickness or introduces closure risks. A tie-layer choice must be supported for its adjacent materials and process; barrier and adhesion are independent acceptance questions.
21. How do layer thickness fractions differ from layer mass fractions?
A multilayer drawing often gives thickness fractions, while a purchase or formulation comparison may need mass fractions. These are equal only under matching density assumptions. Identify each layer, its density basis and whether the drawing includes all adhesive or coating layers. A layer fraction does not establish oxygen or moisture barrier performance.
Hypothetical calculation: a 100 µm structure contains layers of 80 µm at 0.90 g/cm³, 10 µm at 1.20 g/cm³ and 10 µm at 0.95 g/cm³. Using areal mass in g/m² = thickness in µm × density in g/cm³ gives 72 + 12 + 9.5 = 93.5 g/m². The middle layer is 10% of thickness but 12 ÷ 93.5 × 100 = 12.83% of mass. All inputs are illustrative.
22. Which evidence should a barrier-resin and tie-layer comparison request?
Use the following application-specific comparison record to make the enquiry and qualification decision explicit.
| Decision area | Evidence to request | How to interpret it |
|---|---|---|
| Layer map | Resin grade, thickness and each interface | Treat interface compatibility separately from bulk resin identity. |
| Barrier claim | Gas or vapour, method, temperature and humidity | Compare the same exposure and reporting basis. |
| Process | Extrusion, orientation or thermal history as relevant | Record the actual converted structure. |
| Qualification | Bonding, package integrity and intended-contact evidence | A resin property is not the finished-package result. |
23. How should a changed barrier or interlayer-bond result be investigated?
If barrier or interlayer adhesion changes, first verify the converted layer thickness and exposure conditions. Inspect whether process history or the adjacent resin changed with the trial. Do not compensate for an unexplained interface failure by simply increasing a nominal tie-layer fraction without controlled evidence.
24. Frequently asked questions
Can EVOH replace the tie layer?
Do not make that substitution based on family names. Barrier and adhesion functions must each be fulfilled in the actual structure.
Does a low oxygen-transmission result prove shelf life?
It is one measurement on a specified test object. Establish the complete product and package evaluation before making a shelf-life claim.
Is equal melt index enough to match coextrusion grades?
No. Review the grades' relevant processing behavior and the actual line; the technical literature explicitly cautions against relying only on melt-index matching. [B3]
Is a tie layer itself the main barrier layer?
Not necessarily. Its principal role may be interfacial bonding; the full construction defines the barrier function.
Why do barrier values need humidity conditions?
Moisture can change transport behaviour in susceptible materials, so unmatched conditions can mislead comparisons.
Can resin data alone predict shelf life?
No. Construction, conversion, seals, contents and storage exposure also matter.
Is transmission rate the same quantity as permeability?
No. They use different thickness and driving-force bases; identify the method and reported quantity.
Does average film gauge describe the barrier after forming?
Not necessarily. Local thinning, damage and package geometry require evaluation.
Can stronger interlayer adhesion repair a leaking seal?
Not by assumption. Layer bonding and seal/closure integrity are different failure questions.
Is a 10% thickness layer always 10% of structure mass?
No. Different layer densities change the mass fractions.
Can the numerical example predict oxygen transmission?
No. It is a geometry and mass calculation, not a barrier model.
Should a tie-layer RFQ identify both adjacent materials?
Yes. Identify the interface, actual grades and relevant process conditions.
25. References
Links inside sections are supplier or standards-body context for the statements they accompany.
Last revised 2026-10-27.
Related guides
- Flexible Packaging Films And Roll-Stock Selection
- Desiccant Sachets And Moisture Control
- Flexible Packaging Pouches & Rollstock
- Solvent-Free Lamination Adhesives
- Industrial Laboratory Testing, Standards & Product Verification
Explore further
Product and material pages
Material card: High-Barrier Polymer Resins & Tie-Layer Materials (listed in Products & Solutions).
Comparisons
Glossary terms
Oxygen transmission rate · Water-vapour transmission rate · Adhesion · ASTM D3985 · ASTM F1249 · Change control · Delamination · EVOH · Lead time · Migration · Recyclability · RFQ · Tie layer
Tools
Product Finder · Solution Finder (Packaging barrier shortfall (moisture or oxygen)) · Manufacturer Finder · RFQ brief