A packaging update often begins with a simple decision: a new bottle shape, a different supplier, or a fresh look for an existing product.

The opening appears to be the same size, so keeping the original aluminum foil seal liner seems reasonable. But once production starts, the seal may behave differently.

What changed?

Selecting a bottle seal liner requires more than matching its diameter. The bottle, cap, contents, and sealing process all need to be considered together.

Start with the Bottle Material

Bottles made from PET, PE, PP, or glass can require different sealing-layer specifications. A liner selected for one container material should not automatically be assumed suitable for another.

When requesting aluminum foil seal liners, identify the bottle material clearly. If it is unknown, ask your bottle supplier for the specification before proceeding with material selection.

Look Beyond the Opening Diameter

Two bottles with the same nominal opening size may differ in their neck finish, sealing surface, and cap fit.

Provide a bottle drawing or physical sample together with the cap. This helps the supplier assess the complete packaging combination rather than relying on a single measurement.

Consider What Goes Inside

A bottle containing a dry powder presents a different application from one containing an oily liquid or acidic product.

Describe the contents, filling conditions, and intended storage environment. These details help establish the compatibility and testing requirements for the liner.

Define the Opening Experience

Think about how customers should remove the seal. Is easy peeling important? Are there specific expectations for the appearance of the bottle opening after removal?

Discuss these requirements during selection so they can be included in the sample evaluation.

Test Before Making the Change

A sample that fits the bottle is a starting point. Final suitability should be assessed using the actual container, cap, contents, and production equipment.

This is especially important when changing bottle suppliers, container materials, or an existing packaging specification.

Discuss Your Bottle Seal

Why Is Your Bottle Foil Seal No Longer Sealing Consistently?

The product is familiar. The packaging has been running for months. Then the production team notices that some seals are lifting, opening differently, or failing the usual checks.

For purchasing and production teams, the immediate question is often whether the liner needs to be replaced.

Before deciding, it helps to establish what has changed. A structured review gives your packaging supplier more useful information and helps guide the next trial.

Compare the Current Packaging with the Last Successful Batch

Start by reviewing the bottle, cap, and aluminum foil seal liner specifications.

Has the bottle supplier changed? Is the container material identical? Have there been revisions to the cap, neck finish, or liner?

Even when the packaging looks similar, these details deserve confirmation. Keep samples from both the successful and affected batches where possible.

Describe the Problem Precisely

“Poor sealing” can describe several different observations:

• Part of the liner does not appear to bond.

• The seal lifts during handling.

• Leakage occurs after storage or transport.

• The liner is harder to remove than expected.

• The appearance after opening differs between samples.

Photographs, batch identification, and a short explanation of when the problem occurs help make the assessment more specific.

Review the Production Conditions

Record the equipment settings and operating conditions for the affected batch. Include line speed, cap application settings, and any recent equipment adjustments.

Also note whether filling conditions changed or whether product residue was observed around the bottle opening.

These observations provide context for an investigation; they do not, by themselves, establish the cause.

Evaluate Changes Through Controlled Trials

When several factors are changed together, it becomes difficult to identify which adjustment affected the result.

Work with your production team, equipment provider, and packaging supplier to plan a controlled trial. Keep records of the conditions and evaluate samples using agreed acceptance criteria.

Checks should reflect the actual application, including storage and handling where relevant.

Give Your Supplier a Clear Starting Point

For an initial review, prepare:

• Bottle and cap specifications

• Current liner identification

• Product contents and filling conditions

• Equipment details and operating settings

• Photos or samples of the issue

• A record of recent packaging or process changes

Talk to Yangbo About Your Seal Liner Application

If you are reviewing an existing aluminum foil seal liner or assessing an alternative, share your packaging details and the issue you have observed.

Yangbo can discuss liner requirements and the information needed for sample evaluation.

Discuss Your Bottle Seal Liner Requirements

Liner Requirements with Yangbo

Yangbo offers aluminum foil sealing liners for bottle packaging, with specifications evaluated according to the application.

Send us your bottle material, opening dimensions, cap details, contents, and estimated quantity to begin the discussion.

Explore Yangbo’s Aluminum Foil Seal Liners