CB6958 Fluorinated Ethylene Propylene Copolymer Film (FEP/F46 Film)

Fluorinated Ethylene Propylene Copolymer Film (FEP/F46 Film) Description

FEP film, synthesised from tetrafluoroethylene and approximately 15% hexafluoropropylene, is a melt‐processable modification of PTFE that offers improved fabrication flexibility. It operates over a temperature range of –200°C to +205°C (melting point: 304°C) while maintaining moisture absorption below 0.01% and stability under ultraviolet light. The material has a surface energy of 18 dynes/cm, which results in non‐stick release properties that exceed those of silicone or polyethylene films. In electrical applications, FEP functions as an insulator with a dielectric strength of ≥80 kV/mm, a volume resistivity exceeding 10¹⁸ Ω·cm, and a dielectric constant of 2.1 for frequencies up to 1 GHz. Chemically, it exhibits almost complete inertness and resists concentrated sulphuric and nitric acids, strong bases (for example, 50% NaOH), organic solvents (ketones, alcohols) and aggressive oxidisers without degradation. Mechanically, FEP shows a tensile strength of 20–30 MPa, elongation of 250–330% and a modulus of 500 MPa, although it exhibits creep when subjected to sustained loads. Its optical clarity (92% visible light transmission) and compliance with FDA/ISO 10993 standards allow its use in high‐purity medical device packaging (surgical trays, IV bags), transparent wire/cable insulation for aerospace and 5G networks, photovoltaic solar panel encapsulation and release liners for composite manufacturing. Additional applications include corrosion‐resistant laboratory tubing and chemical tank linings. Limitations include radiation‐induced degradation and lower rigidity in comparison with structural plastics. FEP films are extruded at thicknesses ranging from 12–250 μm for these specialised applications.

Fluorinated Ethylene Propylene Copolymer Film (FEP/F46 Film) Applications

FEP film is used in high‐purity electrical insulation for aerospace wiring, 5G/6G coaxial cables and flexible printed circuits. This is due to its dielectric constant of 2.1 and its operability over a temperature range of –200°C to +205°C. The film’s surface energy of 18 dynes/cm is utilised to produce non‐stick release liners for composite manufacturing and 3D printing build surfaces, thereby preventing unwanted adhesion. In medical and pharmaceutical sectors, FDA‐compliant FEP is used for sterile blister packaging, IV bag liners and vial seals, relying on its chemical inertness and moisture absorption below 0.01%. In renewable energy, it is employed as a solar panel encapsulant with ultraviolet stability of over 20 years and a light transmission of 92%. Industrial applications include tank linings for the storage of sulphuric and nitric acids, semiconductor wet‐process tubing and laboratory equipment such as FEP beakers. Emerging applications cover gas barrier seals in hydrogen fuel systems and silver‐coated FEP for transparent conductive films in touchscreens, as well as electric vehicle battery insulation where flame resistance (LOI 95%) is required to inhibit thermal runaway. Its optical clarity, stable electrical properties and chemical resistance support its use in advanced technology sectors.

Fluorinated Ethylene Propylene Copolymer Film (FEP/F46 Film) Packaging

The products are packaged in customised cartons of various sizes depending on the material dimensions. Small items are packed in PP boxes, whereas larger items are placed in custom wooden crates. Packaging follows prescribed customisation, and appropriate cushioning materials are employed to maintain protection during transportation.

Packaging: Carton, Wooden Box, or Customized.

Please review the packaging details provided for your reference.

Manufacturing Process

1.       Testing Method

(1)    Chemical Composition Analysis – Verified using techniques such as GDMS or XRF to ensure compliance with purity requirements.

(2)    Mechanical Properties Testing – Includes tensile strength, yield strength and elongation tests to assess material performance.

(3)    Dimensional Inspection – Measures thickness, width and length to ensure adherence to specified tolerances.

(4)    Surface Quality Inspection – Checks for defects such as scratches, cracks or inclusions through visual and ultrasonic examination.

(5)    Hardness Testing – Determines material hardness to confirm uniformity and mechanical reliability.

Please refer to the SAM testing procedures for detailed information.

Fluorinated Ethylene Propylene Copolymer Film (FEP/F46 Film) FAQs

Q1. What are FEP Film’s defining advantages over PTFE?

FEP film possesses chemical and thermal resistance comparable to PTFE. It is melt‐processable using extrusion or moulding, exhibits 92% visible light transmission and maintains a surface energy of 18 dynes/cm. Its temperature range is –200°C to +205°C with moisture absorption below 0.01%.

Q2. Key electrical properties?

FEP film provides dielectric stability with a dielectric strength of ≥80 kV/mm, a volume resistivity exceeding 10¹⁸ Ω·cm and a dielectric constant of 2.1 with a dissipation factor below 0.0007 at frequencies up to 1 GHz. This facilitates high-frequency signal performance in 5G/6G cables and microelectronics.

Q3. Top industrial applications?

Industrial applications include wire insulation for aerospace and defence (meeting mil-spec MIL-W-22759), medical device packaging compliant with ISO 10993 and FDA standards, solar panel encapsulation with ultraviolet stability over 30 years, and release liners for composite manufacturing. Emerging applications comprise gas barrier seals for hydrogen fuel systems and silver-coated FEP for transparent conductive films in flexible displays.

Related Information

1.       Common Preparation Methods

FEP film is manufactured by free-radical copolymerisation of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) monomers in a typical ratio of 85:15 in an aqueous emulsion or suspension system. The process operates under pressures of 3–5 MPa and temperatures between 40–120°C, initiated by inorganic peroxides such as ammonium persulphate. The resulting copolymer dispersion is coagulated, washed and dried to form granular resin. This resin is then melt-extruded by feeding pellets into an extruder maintained between 300–380°C, thereby ensuring the process remains within a narrow thermal window to avoid degradation. The extruded film passes through precision-controlled chill rolls cooled to 20–50°C to rapidly solidify it into an amorphous, transparent state, followed by optional biaxial orientation (stretching at 100–150°C) to improve mechanical strength and barrier properties. Post-processing includes surface treatment by corona discharge to improve adhesion in laminates and slitting to specified widths (0.1–1.5 m) and thicknesses (12–250 μm). Quality control involves tests for dielectric strength, optical clarity and chemical purity in accordance with ASTM/ISO standards prior to packaging in dust-free environments.