Pressure Sensitive Seals Cap Liners, 25 mm

Pressure-sensitive sealing liners for 25 mm jars are single-use protective seals that, once the cap is tightened, adhere to the rim of the jar neck and seal the contents until first opening. They serve two purposes at once: they protect the contents from leaking and drying out during transport and storage, and at the same time give the customer a visible proof of first opening. They are particularly suitable for small jars containing balms, creams, butters, powder products or samples.

It is a thin liner made of polyethylene (PE) with an adhesive layer that is activated by pressure. Unlike induction seals, it requires no equipment or heat.

How the liner works

• Pressure-sensitive adhesive – the liner is placed inside the cap with the adhesive side facing the neck. When the cap is tightened, it is pressed onto the rim of the jar and adheres to it.
• Tamper evidence – after unscrewing the cap, the seal remains on the jar and the customer removes it by hand. A broken or missing seal is a clear sign that the packaging has already been opened.
• No equipment needed – sealing is done simply by tightening the cap, making it accessible for small production runs and manual filling.
• Content protection – the liner limits the leakage of contents during transport and restricts air access to the product until first opening.

Practical use

The liner is used on jars with a smooth and flat neck rim, where the adhesive can grip around the full circumference. The neck rim must be clean and dry before sealing, free of any product residue. After filling, the cap with the inserted seal is tightened evenly and firmly. Before dispatching a larger batch, it is worth checking the seal on a few units.

The liner performs most reliably with dry, powdery and thick contents, such as balms, butters, solid deodorants, salts or powders. With oils and liquid products, it is advisable to verify the seal in advance: oil on the neck rim reduces the adhesive's grip and the seal may then fail to hold.

Good to know

• Choosing by cap size – the liner diameter must match the inner diameter of the cap and the neck diameter of the jar. Compatibility with a specific jar and cap from the Handymade range is best verified by the neck type listed in the packaging parameters.
• Suitability for cosmetics – the packaging material is suitable for use with cosmetic products and meets the applicable regulatory requirements. The declaration is included in the product parameters.
• Even tightening – when closing by hand, the cap must be tightened evenly around the full circumference. Uneven pressure means part of the circumference will not adhere.
• Recycling – the liner is made of polyethylene and, once removed from the jar, belongs with plastic waste.

Frequently asked questions