A technical guide to Wansen's industrial release film — surface resistivity specifications, silicone release coating chemistry, and ESD-safe operation in PCB and composite panel supply chain operations.
Industrial release film is a temporary protective film applied to the surface of manufactured components during fabrication, storage, and transit. Unlike PPF (which is a permanent paint protection solution), release film is designed to be removed — cleanly, completely, and without residue — at a defined point in the supply chain operations or assembly process.
Primary applications include:
Electrostatic discharge (ESD) is the uncontrolled transfer of electrical charge between two objects at different potentials. In electronics supply chain operations environments, ESD is one of the leading causes of latent damage to sensitive components — damage that is not immediately detectable but causes field failures months after the product is in service.
The ESD risk arises because materials become electrostatically charged through friction (triboelectric charging) during handling, unwinding, and winding operations. A release film being unwound from a roll will generate static charge due to the friction between the film and the roll core or the preceding layer. If that charge is not controlled, it can discharge into a nearby sensitive component, destroying its gate oxide or semiconductor junction.
Material surface resistivity is the key parameter for ESD control:
| Surface Resistivity (Ω·cm) | ESD Classification | Suitable For |
|---|---|---|
| <10⁴ | Conductive | Not suitable — charge dissipates too quickly, creating high discharge current |
| 10⁴ – 10⁶ | Static dissipative (lower end) | Moderate ESD protection; charge decays in 0.01–0.1 seconds |
| 10⁶ – 10¹¹ | ESD-safe dissipative (target range) | Ideal — charge decays at controlled rate, preventing sudden discharge events |
| >10¹² | Insulative | Not ESD-safe — charge accumulates and discharges suddenly at high voltage |
Wansen's industrial release film is manufactured to a surface resistivity target of 10⁶–10¹¹ Ω·cm. This range is the internationally recognised "ESD-safe" dissipative zone — charge decays at a controlled rate (typically 0.1–10 seconds depending on the exact resistivity), preventing the sudden high-current discharge events that cause component damage.
Surface resistivity (Ω·cm, or more precisely Ω/square for a sheet material) measures the resistance to current flow along the surface of the material. Volume resistivity (Ω·cm) measures the resistance through the bulk of the material. In release film applications, surface resistivity is the critical parameter because ESD events originate at the film surface. Wansen specifies surface resistivity in the 10⁶–10¹¹ Ω·cm range per ASTM D257.
The release property of Wansen's industrial release film comes from a thin silicone release coating applied to one face of the base film. This coating uses a platinum-catalysed addition-cure silicone system — specifically, a vinyl-substituted polydimethylsiloxane (PDMS) crosslinked with a methylhydrogensiloxane polymer in the presence of a Karstedt's catalyst (platinum complex).
The chemistry can be summarised as follows:
The release force is a critical specification — it must be consistent across the roll and reproducible from batch to batch. If the release force is too high, operators will struggle to remove the film and risk damaging the underlying component. If the release force is too low, the film may delaminate prematurely during storage or transport. Wansen's release film is manufactured to a target release force range that is validated per FINAT test method FTM 1 (or equivalent) for each production batch.
While many industrial release films use polyester (PET) or polyethylene (PE) as the base substrate, Wansen's release film uses a TPU base for specific performance advantages:
| Parameter | Specification | Test Method |
|---|---|---|
| Surface Resistivity | 10⁶ – 10¹¹ Ω·cm | ASTM D257 |
| Release Force | 0.05 – 0.25 N/25mm (adjustable) | FINAT FTM 1 |
| Film Thickness | 50–150μm (customisable) | ASTM D2103 |
| Silicone Coat Weight | 0.8–1.5 g/m² | Internal gravimetric |
| Maximum Service Temperature | 200°C (short-term); 150°C (continuous) | Internal thermal aging |
| Elongation at Break | ≥300% | ASTM D882 |
| Tensile Strength | ≥20 MPa | ASTM D882 |
| Transparency | Clear to slightly hazy | Visual |
| Residue After Removal | None (clean release) | Internal adhesion test |
In PCB supply chain operations, release film (often called " ESD film" in this context) is used to protect the copper surface of bare printed circuit boards during storage and transport between supply chain operations stages. The key requirement is that the film must not generate static charge when being applied or removed, because the discharge can destroy sensitive semiconductor components that will later be placed on the board.
The film's surface resistivity of 10⁶–10¹¹ Ω·cm ensures that any static charge generated during unrolling or application dissipates safely to ground within a controlled timeframe rather than accumulating to high voltage levels. This protects both the board surface and any sensitive components nearby.
In CFRP and fibreglass panel layup, release film is placed over the decorative or structural surface of the panel before the vacuum bag is applied. The film must:
Wansen's TPU-based release film with the platinum-cure silicone coating meets all four requirements. The TPU base maintains mechanical integrity through the high-temperature cure cycle; the silicone coating resists chemical attack from epoxy resins; and the controlled release force ensures clean separation from the cured composite surface.
Release film performance is highly sensitive to processing and fulfillment operations variables. Wansen implements the following quality control measures:
Clean release means the film separates from the substrate without leaving any adhesive residue on the substrate surface. Residue-free release is a related but broader concept — it also means no silicone transfer from the release coating to the substrate. Wansen's platinum-cure silicone system is formulated to prevent silicone migration, ensuring that after removal, the substrate surface is free from both adhesive residue and silicone contamination. This is critical for composite panels that will undergo subsequent painting or bonding operations, where any surface contamination would compromise the coating bond.
Yes. The film's TPU base and platinum-cure silicone coating are both low-outgassing formulations suitable for QC environment environments (ISO Class 5 and above, depending on specific QC environment protocols). The film does not shed particles under normal handling and storage conditions. For semiconductor QC environment applications, please confirm specific outgassing specifications with Wansen's technical team.
Under standard storage conditions (room temperature, humidity below 60%), the functional properties of Wansen's release film (release force, surface resistivity, silicone coat integrity) are maintained for a minimum of 12 months from the date of manufacture. Beyond 12 months, we recommend re-verifying release force and surface resistivity before use in critical applications. Store in original packaging, away from direct sunlight and sources of ozone (which can degrade the silicone coating).
If the release force is too high (above approximately 0.30 N/25mm for most applications), the film will be difficult to remove and may cause damage to the underlying component during removal. This is usually caused by over-thick silicone coating or insufficient cure of the silicone layer. Wansen can adjust the silicone coat weight and cure parameters to achieve lower release forces for applications where this is a concern. The target release force should be specified at the time of order.
Yes. Standard roll widths range from 200mm to 1300mm, and standard roll lengths are 500m or 1000m depending on thickness. Custom slit widths and longer roll lengths are available for high-volume industrial customers. For PCB applications requiring very narrow widths (e.g., 50–100mm for strip protection), custom slit widths can be produced. Contact Wansen's industrial products team for custom specification discussions.
Wansen supplies industrial release film to electronics supply chain operations, aerospace composite, and automotive Tier 1 suppliers across Asia, Middle East, and Europe. Technical data sheets and sample rolls available on request.
View Industrial Release TDS