Adhesive EPTFE Breather Vent For Flexible Intermediate Bulk Container Liners

The adhesive ePTFE breather vent for Flexible Intermediate Bulk Container (FIBC) liners is a clean, efficient pressure equalization and dust control component designed for the form-fit PE or PA liner bags inserted inside standard FIBC bulk bags. This vent is a precision die-cut patch of high-airflow ePTFE waterproof breathable membrane, backed with a durable, high-tack pressure-sensitive adhesive designed to bond permanently to polyethylene and polyamide films. It is applied directly over a pre-punched or laser-cut vent hole in the liner film, providing a dedicated breathing pathway for the liner. During filling, the vent allows the displaced air to rapidly escape, capturing any fine powder dust within the liner and preventing the liner from ballooning and bursting. During discharge, it allows air to re-enter the liner, preventing vacuum collapse and ensuring complete, smooth powder flow. The vent's adhesive format enables simple, fast application during liner manufacturing, without the need for heat sealing or welding equipment.

FIBCs are often used with an inner liner bag, typically made of PE or PA film, to provide a moisture barrier, to protect the contents from contamination, or to contain fine powders that would otherwise sift through the woven outer bag. This liner is a sealed bag. During filling, the liner must breathe. As powder is pneumatically conveyed or gravity-fed into the liner, the displaced air must escape. If the liner has only a small open vent, fine dust escapes, causing product loss and a workplace dust hazard. If the liner is not vented, it inflates and bursts, stopping the filling process and causing a major mess. During discharge, the liner collapses as the powder exits. If air cannot re-enter, the liner forms a vacuum that stops the powder flow. An effective, easy-to-apply liner vent is critical to the function of the FIBC system.

The adhesive ePTFE breather vent is the ideal solution for liner bags. The ePTFE membrane provides high airflow with low pressure drop, allowing the displaced air to escape rapidly during filling. The membrane captures dust particles, ensuring clean air exhaust. The strong, flexible adhesive backing bonds permanently to the PE or PA liner film, creating a leak-tight seal. The patch is applied in a simple peel-and-stick process, which can be easily integrated into the liner manufacturing line. The membrane is hydrophobic, preventing moisture from entering the liner during storage. The vent patch is thin and flexible, moving with the liner without delaminating.

• PE liner bags for FIBC bulk bags (powders, granules)
• PA barrier liner bags for oxygen-sensitive products
• Form-fit liners for chemical powder and pigment FIBCs
• Food-grade liner bags for flour, sugar, and starch
• Pharmaceutical-grade liner bags for APIs and excipients
• Liner bags for carbon black, silica, and mineral powders

During liner manufacturing, a vent hole is punched or laser-cut in the film. The operator peels the release liner from the adhesive vent patch and applies it over the hole, pressing firmly to ensure a complete bond. During filling, the displaced air flows out through the ePTFE membrane, which captures any dust particles. The liner does not inflate or burst. During discharge, air flows back in through the membrane, preventing vacuum and ensuring complete emptying. The hydrophobic membrane protects the contents from moisture.

1. Determine the liner film material (PE or PA) to select the optimal adhesive formulation.
2. Calculate the required vent airflow based on the fill rate and the liner volume.
3. Size the vent patch to provide the necessary airflow area.
4. Select the membrane grade: standard hydrophobic for most applications; oleophobic for powders with oily or sticky characteristics.
5. Test the complete liner system: fill/discharge cycle, dust containment, and adhesive bond strength after simulated transport and temperature cycling.

• Q: Will the adhesive bond to the PE film permanently, or will it peel off over time?
  A: The high-tack acrylic adhesive is specifically formulated for low-surface-energy polyolefin films. It creates a strong, permanent bond that does not peel, even with the flexing and movement of the liner during filling and discharge.
• Q: Can the vent patch be applied to a liner that has already been inserted into the FIBC?
  A: The vent patch is best applied to the liner during the liner manufacturing process, before insertion into the outer bag. Applying it to an already-inserted liner is possible but more difficult.
• Q: Is the vent patch resistant to the chemicals that might be in the powder?
  A: The ePTFE membrane is chemically inert to virtually all powders. The acrylic adhesive is resistant to mild chemicals. For aggressive chemical powders, a specialized adhesive may be required.
• Q: Does the vent patch allow moisture to enter during high-humidity storage?
  A: The hydrophobic ePTFE membrane is a moisture barrier. It prevents liquid water and significantly reduces water vapor ingress, protecting the contents.
• Q: Can the vent be used with a nitrogen-purged liner?
  A: The vent allows the displaced nitrogen to escape during purging. For applications requiring a fully sealed atmosphere after purging, the vent can be combined with a one-way valve or a temporary seal.