Vented Seal Liners
A one-way membrane welded into the induction liner lets gas escape while the liquid stays sealed in — for packs that build up pressure.
How it seals
Some products generate gas after filling: agrochemical formulations, liquid fertilisers, peroxide and bleach-type chemistry. Shake a bottle in transit or move it between climates, and the pressure builds until the container bulges or the cap bursts. A vented seal liner solves this at the seal itself.
The structure is an induction liner with an ultrasonically welded one-way vent membrane: gas passes out through the membrane, liquid cannot pass back. You keep the tamper-evident, leak-proof induction seal and lose the pressure problem — no changes to the bottle, the cap or your filling line.
The vent membrane is engineered for resistance to surfactants and aggressive agrochemical carriers, which is why the family is widely specified on crop-protection and liquid-fertiliser packs. Perforated and micro-perforated variants handle milder degassing needs at lower cost.
Specification
| Sealing method | Induction heat sealing with a welded vent membrane |
|---|---|
| Vent | Ultrasonic-welded one-way membrane (gas out, liquid stays in) |
| Builds | PE · PET · EPE backings, standard and high-barrier grades |
| Diameter | 9–182 mm; perforation patterns to your drawing |
| Thickness | 0.2–1.2 mm total |
| Branding | Printed opening instructions, steel-stamp embossing, pull-tab |
| Best for | Agrochemicals, liquid fertilisers, hydrogen-peroxide and bleach-type fills |
| MOQ | Varies with diameter and structure — send your container size for exact minimums |
| Packaging | PE bag inner, thickened corrugated carton outer (export packing) |
| Storage | −20 °C to 50 °C, away from direct sunlight |
| Lead time | Typically 7 days after order confirmation |
Welded one-way membrane — gas escapes, liquid stays sealed in
Typical applications
Where this family is specified
| Crop protection (agrochemicals) | One-way venting for formulations that gas in transit and storage |
|---|---|
| Liquid fertilisers | Pressure relief on bottles shipped through temperature swings |
| Hydrogen peroxide | Slow decomposition releases oxygen — vented liners keep packs stable |
| Bleach & alkaline cleaners | Chemical-resistant membrane grades for household and industrial fills |
| Other degassing liquids | Perforated and micro-perforated variants to your drawing |
Choosing the right build
The vent must be matched to how fast your product actually gases: too little flow and pressure still builds, too much and the membrane loses liquid tightness. Send us your formulation (or its SDS) and the distribution route, and we propose the membrane grade and validate it against your product before production.
If your product does not gas but you need an induction seal, the standard induction family is the right place; if the pack only needs mild pressure equalisation, perforated variants cost less than a welded membrane.
Other liner families
Not sure which family fits your pack?
Tell us what you fill, what it goes into and how you seal it today. Our engineers will come back with a matched structure, a datasheet and sample liners.