PEI Film (Grade DFPEI | 0.025–0.5mm)
We supply high-temperature PEI Films (ULTEM™ equivalent, grade DFPEI) in thicknesses from 0.025mm to 0.5mm and widths up to 1060mm. Featuring a 𝑇𝑔 of 217°C, RTI of 170°C, 85.6% transparency, stable dielectric constant (𝐷ₖ = 3.0) and FAR flame retardancy, this thermoformable film is engineered for acoustic speaker diaphragms, supercapacitors, FPC insulation, and green hydrogen electrolysis. Share your specs for a quick quote.
Product information
Published information supports preliminary product selection. Confirm the exact grade, dimensions, tolerances, documentation and application suitability with the quotation for your order.
Description
PEI (Polyetherimide) Film is a high-performance amorphous film engineered for severe thermal, electrical, and acoustic applications. Operating continuously at 160°C to 180°C (RTI 170°C, 𝑇𝑔 of 217℃), it delivers high tensile strength (>100 MPa), low thermal shrinkage (＜0.2% at 200°C), and excellent thermoforming/heat-sealing capability.
With a stable dielectric constant (𝐷ₖ = 3.0) and low dissipation factor ( Df = 0.006), PEI film provides superior electrical insulation across wide temperature and frequency ranges. Featuring 85.6% light transmittance and FAR flame retardancy, it is widely specified for speaker diaphragms, high-temp supercapacitors, green hydrogen electrolysis, and outdoor electronics.
Property Datasheet Summary (DFPEI Grade)
| Property / Parameter | Technical Value |
| Grade Code & Color | Grade DFPEI / Natural Amber & Black |
| Thickness & Width | Thickness: 0.025 – 0.5 mm / Width: < 1060 mm |
| Surface Textures | Polished/Matte, Matte/Velvet |
| Glass Transition Temp ( 𝑇𝑔 ) | 217°C |
| Relative Temp Index (RTI) | 170°C (Continuous 160℃ – 180℃) |
| Tensile Strength (MD/TD) | 103 MPa / 101 MPa |
| Dielectric Constant (𝐷ₖ) | 3.0 (1MHz) |
| Dissipation Factor (D𝑓) | 0.006 (1MHz) |
| Light Transmittance | 85.6% (Visible/IR/Microwave) |
How this product is normally specified
This product is supplied as rolls or pre-cut sheets for die-cutting, thermoforming, or laminating:
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Thickness & Width: Thickness (0.025–0.5 mm) and roll width (up to 1060 mm)
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Surface Texture: Polished/Matte or Matte/Velvet finish
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Color & Format: Natural Amber or Black in rolls or sheets
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Conversion Need: Thermoforming, heat sealing, die-cutting, or laminating
Where this material can fit
Typical applications for high-temperature PEI films include:
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Acoustics & Audio: Acoustic speaker diaphragms, headphone membranes, and receiver domes
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Energy Storage & Hydrogen: High-temp supercapacitor dielectrics and electrolyzer membranes
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Electronics & FPC: Flexible printed circuits (FPC), transformer insulation, and slot liners
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Aerospace & Auto: Aircraft interior insulation (FAR/ABD compliant) and sensor windows
What to confirm before ordering
To recommend the right PEI film specification, please confirm:
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Target thickness (0.025–0.5 mm), width (up to 1060 mm), and roll/sheet length
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Surface texture (Polished/Matte or Matte/Velvet) and color
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Application (speaker diaphragm, supercapacitor, FPC insulation, hydrogen energy)
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Required trial quantity and repeat demand
Send us the information you have. We will review technical details before confirming the quotation.
Material overview
Understanding PEI (Polyetherimide)
Why engineers use it
- Good heat resistance and stiffness for structural and electrical parts.
- Stable dimensions and predictable processing in suitable equipment.
- Inherent flame, smoke and electrical performance for many technical applications.
- Available in natural amber and opaque or reinforced grades.
- Can be molded, machined or printed where the appropriate material form is available.
Limits to consider
- Some chemicals and stress-cracking agents require careful compatibility review.
- Moisture control before high-temperature processing is important.
- Continuous chemical or wear duty may favor PEEK or PPS.
- Reinforced grades change impact, surface and directional properties.
- Regulated uses require the correct documented grade, not a generic PEI designation.
Grades and product forms
Unfilled PEI emphasizes the base material’s thermal, electrical and dimensional balance. Glass-fiber grades improve stiffness and movement control but change toughness and surface finish. Medical, aerospace or food-contact projects must identify the exact documentation requirement before grade selection.
Performance points to review
| Evaluation area | Why it matters | Information to provide |
|---|---|---|
| Temperature behavior | Useful performance under elevated or changing temperature | Continuous and peak temperature, cycle length and time at load |
| Mechanical response | Strength and stiffness must match the real part geometry | Load direction, stress level, impact and fatigue expectations |
| Environmental resistance | Fluids, cleaning agents and atmosphere can change service life | Chemical name, concentration, temperature and exposure time |
| Dimensional control | Tight-tolerance parts depend on both material and processing | Finished dimensions, tolerances and assembly conditions |
| Electrical or insulation needs | Electrical requirements may influence grade and thickness | Voltage, dielectric, conductivity or insulation target |
These are engineering discussion points, not guaranteed property values. Final acceptance criteria should be agreed for the selected grade, process and order.
Typical application directions
These examples show where the material may be evaluated. They do not replace a suitability review for the finished component.
Preparing a high-temperature printing project
Provide filament diameter, printer model, nozzle and chamber capability, drying method, build geometry, support strategy and annealing plan. A high-performance filament cannot compensate for a printer that lacks the necessary thermal control.
Where the application is critical, define what a successful trial looks like before material is ordered: dimensions after processing, visual condition, mechanical response, assembly fit or another measurable result.
When another material may be better
PEEK may provide a larger performance margin in more severe heat or chemical service, while lower-cost engineering plastics may be sufficient for moderate conditions. PEI is often chosen when its specific balance of thermal, electrical and structural properties fits the part.
We recommend sharing the current material and the reason it is being reconsidered. Cost, processability, supply form and inspection burden belong in the decision alongside technical performance.
Information needed for an accurate quotation
A useful RFQ reduces follow-up questions and helps us distinguish between a material request and a finished-part requirement.
| Product form | Raw material, stock shape, semi-finished blank or completed part |
|---|---|
| Dimensions | Nominal size, finished size and tolerances |
| Quantity | Trial quantity, first order and estimated annual demand |
| Application | Part function and current material, if any |
| Operating temperature | Continuous range, peak temperature and cycle duration |
| Environment | Chemicals, gases, moisture, pressure, vacuum or outdoor exposure |
| Mechanical duty | Load, speed, impact, wear and mating components |
| Documentation | Drawing revision, inspection, traceability or compliance needs |
| Printing setup | Printer, nozzle, chamber, build plate, drying and annealing capability |
Frequently asked questions
Can I request a sample or trial quantity?
Trial quantities can be discussed according to product form and availability. Tell us what you need to prove during the trial, the intended process and the expected production quantity if the test succeeds.
Do you provide a data sheet or material documentation?
Available documentation depends on the selected material and supply route. List the documents required by engineering, purchasing or quality when you inquire so they can be checked before quotation.
Can the grade be selected from a product name alone?
No. Similar product names can cover different grades, colors, fillers and processes. Selection should be based on the finished application, environment and required property balance.
Can you supply custom dimensions or finished parts?
Custom sizes, blanks or finished parts can be reviewed where appropriate. A drawing with tolerances, quantity and material requirement is the best basis for quotation.
How should we evaluate an alternative to our current material?
Share the current grade, the part’s service conditions and the reason for changing it. A useful comparison looks at failure mode, processing, life, inspection and total project cost—not only a single property value.
What determines lead time?
Lead time depends on product form, grade, size, quantity, documentation, machining and current availability. Confirm the required delivery date and destination with the RFQ rather than assuming a standard schedule.
Send the drawing, application and quantity. We will use the project details to prepare a practical material and supply discussion.
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