How to Choose a Liner for an Existing Bottle Cap
Already Have a Bottle Cap? Check These 3 Areas Before Choosing a Liner
You’ve ordered the bottle caps, and the supplier has given you one diameter. Can you use that number to order the liners?
First, find out what the number refers to. It may be the nominal cap or bottle neck size. The liner has to fit the space inside the cap and meet the top of the bottle rim when the cap is tightened. Before requesting samples, check these three areas on the cap and container you plan to use in production.
1. Turn the cap over and locate the liner seat
Look at where the liner will sit inside the cap. Some caps have retaining tabs or a ring that affects how the liner sits and stays in place. If you have a drawing, mark the usable inside diameter and depth of the liner seat. If you have an existing liner, share its diameter and thickness or provide a sample for comparison.
2. Look straight down at the bottle rim
Find the flat ring at the top of the bottle that contacts the liner. Two containers with the same nominal neck size can have sealing rims of different widths or profiles. If a drawing is available, mark the inner and outer diameters or the width of the sealing surface and identify the bottle material. For a foil liner designed to bond to the rim, that material helps determine which sealing layer to evaluate.
3. Screw the cap onto the bottle and check the assembled fit
Take a side photo to show how the cap sits on the neck when tightened. If you already have a liner sample, check whether it shifts, lifts or sits unevenly. The photo helps your supplier understand the assembly. Use physical samples to verify contact and sealing performance. Let the supplier know whether you need a first-opening seal or a liner that stays in contact with the rim after repeated opening and closing.
Can I start with photos if I don’t have drawings?
Yes. Send the three views below and describe the product and how the package will be used. Drawings or physical samples can follow when dimensions need to be confirmed or trial samples are being arranged.
To discuss cap liner selection with Yangbo, send these three photos
- Inside the cap — show the liner seat and any retaining features.
- Directly above the bottle opening — show the full sealing rim.
- Side view with the cap tightened — show how the cap sits on the neck.
If available, attach drawings showing the liner seat diameter and depth and the bottle rim dimensions. Include a short note about the product contents, filling conditions and opening requirements so we can discuss which liner to evaluate.