Housewell Enterprise Co., Ltd. | HSW

Release Film Technology and Its Applications in the Medical Field

1. Wound Care and Medical Dressings
In the field of wound care, various types of medical dressings—such as band-aids, adhesive tapes, transparent dressings, and foam/hydrocolloid wound patches—extensively use release films as a key component. The main function of the release film in these products is to protect the adhesive (or gel) layer from contamination or damage during sterilization and storage, and to ensure easy removal when applied, allowing the dressing to adhere smoothly to the wound site.

The simplest example is the conventional band-aid: the adhesive side is typically covered with two symmetrical release liners, which are peeled off sequentially during use. These release papers/films are often made of white waterproof paper coated with wax or silicone oil to prevent adhesive bonding and to allow easy removal.

Another growing trend in wound care is the use of silicone gel adhesives in dressings. Traditional medical tapes often use acrylic adhesives, which are highly sticky and may cause secondary skin damage upon removal. In contrast, silicone gel dressings are gentler and more suitable for fragile skin and chronic wounds.

However, as previously noted, the mild adhesion of silicone also presents a challenge: it does not separate well from regular (silicone-coated) release films. As such, dressings using silicone adhesives often pair with fluorosilicone-coated release films to ensure both gentle adhesion and removability. For example, imported soft silicone foam dressings often adopt a dual-layer release film design: the first layer covering the adhesive is a fluorosilicone release film, while the second is a PET film for added stiffness. During application, the PET film is removed first, the dressing is positioned, and the fluorosilicone film is peeled off last.

With technological advancements, non-silicone coating solutions have also emerged that work with silicone gel adhesives. For instance, our company has developed a proprietary non-silicone release coating for medical applications that contains no organosilicone but still performs well with silicone adhesives. These silicone-free release films maintain gentle adhesion, reduce silicone residue, and help lower costs—making them a highlight in material innovation.

Overall, in wound care, release film technologies continue to evolve around two core goals: patient comfort and user convenience. They must ensure a "barrier-free" application while minimizing disruption to the wound or skin upon removal. The material, coating, and structure of the release film directly influence the clinical performance and user experience of these dressings.

2. Surgical Instruments and Fixation Patches

In surgical and emergency scenarios, many instruments and dressings require adhesive fixation devices for immediate use. Release films ensure these devices remain sterile and functionally intact prior to application. A typical example is the incise drape—a transparent adhesive film used to cover the skin around a surgical incision, creating a sterile barrier. To prevent the adhesive from premature exposure before surgery, the drape is packaged with a large release liner. This release paper must be fiber-free (to avoid particle contamination in the sterile field), durable, and easy to peel. Commonly used materials include high-density waterproof paper with a smooth wax or silicone coating, often described as “lint-free, tear-resistant wax release liner.” During use, the sterile assistant typically grips a handle or tab on the release paper to swiftly peel it off in one motion while placing the film on the patient’s skin. Some high-end products even design full-width handles or special tear strips to ease this process.

Besides incise drapes, other adhesive products in surgery and emergency care—such as IV fixation tapes, surgical drape tapes, and catheter stabilizers—also use release films to preserve sterility and adhesive integrity. For example, incise drapes with fluid collection pouches (used during major surgeries) have adhesive areas covered with release liners until use.

These applications require release films with large dimensions, high strength, and smooth peelability. The full-width handle design is specifically developed for such use, enabling secure single-handed operation of even large release films (spanning several dozen centimeters). After fixation, the release film is discarded and does not contact the patient. Nonetheless, its material safety remains critical—it must be non-toxic, sterile, and free of residue or particles in sterile zones. This explains why high-quality release films/papers are highly valued in surgical fields: they must combine industrial-grade mechanical performance with stringent medical-grade hygiene standards—neither can be compromised.

3. Biosensing and Diagnostic Devices

As medicine evolves toward minimally invasive and digital solutions, more biosensors and diagnostic devices are being worn directly on the skin as patches or wearables. These devices usually contain adhesive components (e.g., tapes, electrode gels), which need to be protected by release films before use. Typical examples include ECG electrode patches, EEG electrodes, fetal monitoring patches, and various wearable physiological sensors (such as CGM continuous glucose monitors and TENS electric stimulation patches). For example, a disposable ECG electrode is coated with a conductive adhesive gel that attaches to the skin to transmit signals. To prevent the gel from drying or becoming contaminated, each electrode is covered with a release film at the factory, which is only removed prior to use. These electrodes often use PET as the base film for its durability and clean peel properties. The release coating must also be chemically compatible with conductive adhesives, providing protection without interfering with adhesion or conductivity.

In addition to protective functions, some monitoring patches are designed to be reattached to the release film after use—for instance, reusable neuromuscular stimulation patches and some large-area ECG electrodes. After use, the patient removes the patch and reapplies it to the original liner for future use. In such cases, release films must be durable enough to withstand repeated peel-and-stick cycles. This is typically achieved through high-strength film materials and long-lasting release coatings.

Another important application is transdermal drug delivery patches and certain diagnostic reagent patches—such as nicotine patches, insulin patches, contraceptive patches (TDDS), and allergy test patches. These systems often have complex structures, potentially including a drug reservoir and rate-controlling membrane. The release film directly contacts the drug-containing adhesive layer, which imposes stricter requirements: the film must meet pharmaceutical-grade purity standards (to avoid drug interaction or adsorption) and must comply with pharmacopoeia or regulatory certifications to prove it is safe for human use and does not interfere with the medication. Many pharmaceutical patch manufacturers request DMF (Drug Master File) documentation from release film suppliers to ensure regulatory traceability. These patches typically use high-clarity PET release films so users can see the medication location for accurate placement. Some (such as microneedle vaccine patches) even require the release film to support the microstructure’s insertion into the skin, favoring thicker, stiffer materials like PS or thick PVC films.

Nevertheless, most wearable medical patches use flexible materials to ensure comfort during extended skin contact. Thus, balancing stiffness and flexibility becomes a key design factor: the film must support the application process without curling, while maintaining comfort during wear—especially on curved body parts like shoulders or limbs. “Balanced-flex” PP release films demonstrate their value here, offering support to thin sensors during placement while remaining soft enough to conform to body contours. In short, release films act as “invisible enablers” in biosensing and diagnostic patches—they don’t participate directly in treatment or diagnosis but play a crucial role in enabling the devices’ usability and effectiveness.

4. Sterile Packaging and Medical Device Encapsulation

Sterile packaging is critical to patient safety. Some medical devices and consumables are packaged with adhesive sealing or fixation elements, which are protected by release films until final use.

An example is self-adhesive sterile closures: certain sterile packages (such as surgical instrument kits) use adhesive strips in addition to heat seals for sealing or resealing. These adhesive areas are covered with release paper to preserve stickiness until needed. Such release liners are typically medical-grade silicone-coated papers, pre-applied in sterile environments inside the packaging. They must withstand sterilization processes (e.g., ethylene oxide) and maintain functionality throughout the shelf life without premature bonding.

Similarly, release films are commonly used to protect components of medical devices. For instance, an adhesive-backed sensor will be covered with a release film to prevent exposure during transport; or a semi-sticky protective film might be applied to the surface of an implantable device to prevent scratching, which is removed just before use. In these scenarios, the release film must be sterile (often sterilized alongside the device) and capable of maintaining its physical properties post-sterilization.