Dafu

Select BOPP capacitor film by thickness and service temperature

For capacitor manufacturers and power-electronics material buyers, film selection involves more than choosing a thin gauge. Thickness uniformity, dielectric performance, thermal shrinkage and the required service temperature all need to be considered.

Dafu Ultra-Thin BOPP Film for Capacitor is a biaxially oriented polypropylene film with an overall thickness range of 2-8 μm. The product range includes DFMG, DFMH, DFMS and DFMU, with grade-specific service-temperature limits and thickness ranges shown below.

Grade selection

KPIC: Korea Petrochemical Ind. Co., Ltd. Temperature limits apply to the corresponding grades; they are not a common rating for the whole range.

Available widths

Finished film width: up to 1050 mm. Listed slitting widths for all four grades: 620 mm, 920 mm and 1040 mm, with customization available.

For material evaluation, specify the required grade, thickness, slit width, service temperature and intended application.

Performance characteristics

• Thickness uniformity and transverse flatness: the brochure identifies both as product characteristics, with production capability down to 2.0 μm.
• Electrical performance: high dielectric strength and low dielectric loss. The 3.8 μm laboratory sample recorded a dielectric strength of 550 V/μm and a dissipation factor of 0.00025.
• Mechanical performance: the same sample recorded tensile strength of 200 MPa in MD and 260 MPa in TD.
• Thermal shrinkage: 3.5% in MD and 0.2% in TD at 120°C for 10 minutes for the 3.8 μm laboratory sample. Select service temperature by grade using the selection table.

The numerical values above are laboratory results for 3.8 μm BOPP capacitor film, not guaranteed values. They are provided for reference only. The brochure does not identify the grade of this test sample.

Production capability

Dafu has both sequential and simultaneous stretching manufacturing capabilities.

• Mechanical simultaneous stretching line: main film thicknesses of 2.0-3.8 μm; 5800 mm master roll width; maximum production speed of 240 m/min; full-capacity annual output of 1200 tonnes. Equipped with a FUJI TEKKO high-speed slitting machine.
• Brückner wide-width line: main film thicknesses of 2.4-8 μm; 6400 mm master roll width; maximum production speed of 240 m/min; full-capacity annual output of 3675 tonnes.

These are production-line specifications. Finished film widths are listed in the product description.

Production environment and quality control

The brochure lists a 10,000-grade clean room with real-time temperature and humidity control. Quality checks cover raw materials, production processes and finished products before delivery.

Laboratory equipment includes a MAHR thickness gauge, roughness tester, high-temperature withstand-voltage tester, high-precision high-voltage capacitance bridge, digital megohmmeter, electronic tensile tester and electric weakness tester.

Applications

The 2026 capacitor film brochure lists the following application fields:

• New energy vehicles
• Wind power and photovoltaic systems
• Flexible DC power transmission and transformation
• High-frequency industrial control circuits
• Composite current collectors

Information for material selection

Match the film grade and thickness to the electrical, thermal and processing requirements of the intended application. The grade selection table provides the listed thickness ranges and service-temperature limits; the technical data table provides reference measurements for a 3.8 μm sample.

When discussing samples or specifications, include the intended application, required grade, thickness, slit width and service temperature so that the appropriate material can be evaluated.

Typical property values: 3.8 μm BOPP capacitor film

These values were measured in Dafu's laboratory on 3.8 μm BOPP capacitor film. They are non-guaranteed test values provided for reference only.

Test method listed for all properties: GB/T 13542.2-2021. The brochure does not identify the grade of the tested sample.

MD: machine direction. TD: transverse direction.

Reference results for this sample should not be treated as guaranteed specifications for every grade or thickness. The dielectric-strength test value is not a finished capacitor's rated operating voltage.

Source: Dafu 2026 Ultra-Thin BOPP Film for Capacitor brochure, product technical data sheet.