Electrical Grade PET Film
- Material: Biaxially oriented PET polyester film
- Color: Milky white, hazy white, or natural clear by grade
- Thickness: 50 um – 350 um
- Width: Slit roll or master roll, custom width available
- Surface: Untreated, corona treated, or chemically treated
- Main use: Motors, transformers, FPC, FFC, and electrical gaskets
Films Protective Company is an electrical grade pet film manufacturer for electrical insulation systems that need reliable dielectric strength, controlled thermal class, low heat shrinkage, and clean converting performance. This polyester insulation film is made for stator slot liners, transformer winding barriers, FPC insulation layers, die-cut electrical gaskets, and laminated electrical barriers. Thickness, surface treatment, roll width, and flame-retardant or UL-recognized grade can be selected according to final voltage, working temperature, structure, and safety requirement.
Product Overview
Electrical grade PET film is used as a thin, strong insulation material in motors, transformers, flexible circuits, and electrical parts. In motor production, this PET insulation film must slide into the stator slot without folding, while the cut edge should stay smooth during bending, insertion, and varnish treatment. During sample slitting checks, edge quality is reviewed because burrs or cracks may become weak points after the film is used as a slot liner, phase separator, or inter-turn barrier.
In transformer applications, the film works as a winding barrier between coils, composite sheets, and high-low voltage sections. FPC and FFC insulation layers also need low shrinkage and a clean surface because small dimensional movement can affect alignment, bonding, and electrical spacing. In our in-house sample checks, 125 um film kept shrinkage within 1.5% after 150C for 15 min under controlled test conditions. This value is useful for slot liners, FPC backing, and punched gasket parts.
Benefits
- High dielectric strength helps reduce breakdown risk when thickness, voltage, humidity exposure, and aging conditions are matched correctly.
- Controlled thickness tolerance supports predictable spacing in compact motor, transformer, and FPC designs.
- Good tear resistance and suitable stiffness help the film enter stator slots smoothly.
- Low heat shrinkage helps the film keep its fitted shape during varnish drying, winding tension, and thermal cycling.
- Treated surface options improve bonding with adhesive, resin, varnish, DMD, NMN, or aramid paper.
- Clean die-cutting behavior helps reduce burrs, edge cracks, and weak points in electrical gasket production.
How does dielectric strength affect motor slot and transformer insulation?
Dielectric strength is the key reason electrical grade pet film is selected for stator slot liners, transformer winding barriers, phase insulation, and coil separation. In our typical in-house range, dielectric strength is controlled around 55 – 105 V/um, depending on thickness and grade. A thinner polyester insulation film can save space in compact motors or flexible circuit structures, but the breakdown margin still needs to match working voltage, aging condition, humidity exposure, and thermal class. A thicker film gives better physical separation and handling stiffness, but thickness tolerance must stay controlled.
TDS
Item | Typical Value |
Film type | Electrical grade PET polyester film |
Material structure | Biaxially oriented polyester film |
Common thickness | 50 um - 350 um |
Thickness tolerance | +/-3% to +/-5%, depending on thickness |
Color option | Milky white, hazy white, natural clear by grade |
Dielectric strength | 55 - 105 V/um, typical in-house range |
Volume resistivity | >=1.0 x 10^14 ohm.cm |
Insulation class | Class E 120C or Class B 130C, grade dependent |
Heat shrinkage | <=1.5% at 150C for 15 min, typical sample value |
Flame-retardant option | UL94 VTM or UL-recognized grade upon request |
Applications
- Stator slot liners, slot wedges, phase separators, and inter-turn insulation.
- Transformer winding barriers, coil separation layers, and interlayer insulation.
- FPC and FFC insulation layers requiring low shrinkage and dimensional control.
- Die-cut electrical gaskets, spacers, washers, and insulation pads.
- Wire wrapping, cable insulation, and electrical tape carrier film.
- DMD, NMN, aramid paper, nonwoven, or adhesive laminated insulation structures.
What should be checked when UL or flame-retardant performance is required?
When electrical insulation PET film is used inside motors, transformers, FPC assemblies, or electrical gaskets, the flame rating should be confirmed before production. A standard PET insulation film may have good dielectric strength, but it does not automatically meet UL or flame-retardant requirements. For thin insulation films, UL94 VTM ratings may be more suitable than thick-sheet flame tests. Some assemblies may require a recognized insulation system, not only a single film report. Target thickness, color, flame rating, report availability, lamination structure, and final end-use position should be checked through sample testing.
Loading Details
FAQ
Is electrical grade pet film suitable for motor slot insulation?
Yes. Electrical grade pet film can be used for stator slot liners, slot wedges, phase insulation, and inter-turn insulation when thickness, stiffness, dielectric strength, and edge quality match the motor design.
What insulation class can this PET film support?
Common grades support Class E 120C or Class B 130C. Higher systems should be confirmed by complete structure testing.
Can the film be die cut into electrical gaskets?
Yes. Controlled thickness, clean slitting, and smooth die-cut edges help reduce burrs, edge cracks, and weak points.
Does every grade meet UL or flame-retardant requirements?
No. UL-recognized or flame-retardant grades must be selected separately and confirmed by thickness, color, report, and final application.
