Flexible packaging

A shielding bag is a multilayer flexible package with a metal layer that forms a Faraday cage around the component. It protects its contents from external electrostatic fields, including outside an EPA. It is the only type of flexible ESD packaging suitable for transporting and storing sensitive components outside a protected area.

Our shielding bags are multilayer structures typically made up of a dissipative outer layer (to prevent charge build-up on the surface), a conductive metal layer (which provides electrostatic shielding) and a dissipative or antistatic inner layer in contact with the component. This construction provides both shielding and protection against direct discharges.

Shielding effectiveness is measured according to IEC 61340-4-8: a discharge is applied to the bag and the energy that reaches the inside is measured. IEC 61340-5-3 requires this energy to be below 50 nJ. All our shielding bags are qualified using this method, and the measured value is given in our product data sheets.

Zip-lock shielding bags can be reused several times, provided the closure still seals properly and the metal layer is not punctured or damaged. Single-use heat-sealed bags must be replaced after each use. Visually check the integrity of the bag before each reuse.

An antistatic PE (polyethylene) bag generates little or no electrostatic charge but does not protect against external fields: it should only be used inside an EPA. A shielding bag, thanks to its metal layer, also protects against external fields and is therefore suitable for transport outside an EPA. PE bags are less expensive and suited to handling within a protected area.

Tubing (open at both ends) is preferred for long or irregularly shaped parts that do not fit standard bag sizes, or for high-volume packaging where the tubing is cut to the required length. It also makes it easy to adapt to different formats without stocking several bag sizes.

Our flexible packaging can be closed by heat sealing (with a heated-bar sealer suited to the material), an integrated zip closure, or ESD clips or staples. For moisture barrier applications, heat sealing is mandatory to ensure an airtight seal. Eurostat also offers sealers suited to its packaging.

A moisture barrier bag (MBB) is a multilayer flexible package designed to protect moisture-sensitive devices (MSDs) in addition to providing ESD protection. It includes a layer with a very low water vapour transmission rate (WVTR). Combined with a desiccant and a humidity indicator card (HIC), it keeps the inside environment dry during storage and transport.

An HIC is a humidity indicator card placed inside the sealed package. It contains reactive spots that change colour (typically from blue to pink) when relative humidity exceeds a defined threshold (10%, 20% or 30% depending on the model). Before opening a sealed package, the operator checks the colour of the HIC through the transparent window to make sure the components have not been exposed to excessive humidity.

The amount of desiccant depends on the internal volume of the package, the required storage time, the package’s WVTR and the storage conditions. IPC/JEDEC J-STD-033 provides a calculation method. In practice, our technical teams can help you determine the right quantity for your application. As a reference, one desiccant unit as defined by MIL-D-3464 absorbs at least 3 g of water vapour at 20% RH (25 °C).

A sealed MBB with a correctly sized desiccant generally provides 12 months of protection under standard storage conditions (controlled temperature and humidity). This period is stated on the package. Once opened, the component must be handled according to its MSL (Moisture Sensitivity Level), as defined by IPC/JEDEC J-STD-033.

The choice depends on three main criteria. Where it will be used: only inside an EPA (a PE bag is sufficient) or outside an EPA (shielding is mandatory). Moisture sensitivity: an MSL-rated component (MBB with desiccant and HIC required) or not. Shape and size: standard parts (bags) or unusual or long shapes (tubing). Our technical team can help you select the right solution.

Yes. Our flexible packaging is qualified to IEC 61340 standards for ESD properties and to IPC/JEDEC standards for moisture barrier properties (WVTR). Each product’s data sheet specifies the applicable qualification standards and the measured values.

Yes. Eurostat can produce custom flexible packaging (dimensions, materials, custom printing, specific closures) above certain volumes. Contact our sales team with your specifications for a feasibility study and a quote.