Pressure Sensitive Seals Cap Liners, 51 mm

Sealing inserts for 51 mm jars seal the jar neck on first tightening of the lid – the pressure-sensitive layer adheres to the rim of the neck without heat and without a device. A simple seal is formed that keeps the contents in the jar during storage and transport, and at the same time serves as evidence of integrity: as long as the insert holds on the neck, the product has not been opened. Suitable for jars with a neck diameter of 51 mm for creams, body butters, balms, scrubs, bath salts or dry mask mixes.

How a sealing insert works

The insert is placed into the lid, the lid is screwed onto the filled jar and firmly tightened. The pressure of the thread presses the insert against the rim of the neck and it adheres all around the circumference. When first unscrewed, it remains on the neck and the customer removes it by pulling. It is a single-use element: once detached, it is not used again and the jar is subsequently closed with the lid only.

Key benefits

• Content protection – covering the neck reduces leakage, spillage and contact of the contents with the lid during transport and storage.
• Evidence of integrity – an intact insert shows that no one has opened the jar after filling. For cosmetics sold on, this is reliable information for the customer.
• Sealing without equipment – the seal is created directly when screwing on the lid, without heat and without an additional work step. Suitable even for small batches and manual filling.
• Unobtrusive – the insert does not change the appearance or height of the jar and adds virtually no weight to the packaging.

Use in production

The insert is intended for jars with a 51 mm neck and a screw lid that presses it against the full circumference of the neck when tightened. It works best with thick and semi-solid contents: creams, body butters, balms, solid deodorants, salt and sugar scrubs, clay or powder masks and waxes. With thin, liquid contents it serves more as a seal than as protection against spilling – the overall tightness of the packaging is primarily determined by the lid and how it sits on the neck.

Inserts are placed into the lids before screwing on. For larger batches it is practical to prepare the lids with inserts in advance and then simply close the filled jars.

What's good to know

• Size check – before ordering a larger quantity, test the insert on the specific jar and lid. It must cover the entire rim of the neck and at the same time fit loosely inside the lid.
• Material and contents – polyethylene is generally resistant to water and plant oils. For contents with a higher proportion of essential oils, alcohol or other solvents, we recommend verifying the insert's behaviour with the specific formulation.
• Cosmetic and technical grade – the insert is intended for cosmetic and technical contents. Food contact suitability is not stated for it, so we do not recommend it for food packaging.

Frequently asked questions