Dafu

The Growing Demand for High‑Performance Capacitor Films

The global shift toward electrification and clean energy has placed unprecedented demands on passive electronic components, particularly film capacitors. At the heart of every modern film capacitor lies the dielectric material—and BOPP capacitor film (biaxially oriented polypropylene film) has emerged as the gold standard for DC‑link, pulse, and snubber capacitors in electric vehicles (EVs), wind turbines, photovoltaic inverters, and flexible DC transmission systems. As power densities rise and operating temperatures increase, the need for ultra‑thin, thermally stable, and electrically robust capacitor film has never been greater.

Foshan Dafu New Materials Co., Ltd., a recognized high‑tech enterprise and innovation leader in China’s specialty film industry, has positioned itself at the forefront of this trend. With its latest Brückner asynchronous BOPP capacitor film line now fully operational, Dafu offers a comprehensive portfolio of ultra‑thin capacitor film that meets the most stringent performance criteria for next‑generation power electronics.

State‑of‑the‑Art Production: Dual‑Line Capacity for Ultra‑Thin Capacitor Film

Dafu’s manufacturing strategy is built around two complementary production lines—both sourced from Germany’s Brückner Maschinenbau, the world leader in film stretching technology. The newly commissioned asynchronous stretching line produces BOPP capacitor film in thicknesses from 2.4 μm to 8 μm, with a master roll width of 6,400 mm and a line speed of 300 m/min, delivering an annual capacity of 3,675 tons. This line is designed for high‑volume, cost‑effective production of standard capacitor film grades used in general industrial and automotive applications.

Complementing this is the world’s first mechanical simultaneous stretching line for ultra‑thin capacitor film, which Dafu pioneered earlier. This line specialises in 2.4 μm to 3.8 μm products, maintaining the same 6,400 mm width and 300 m/min speed, with a capacity of 1,200 tons per year. Equipped with high‑precision slitting systems from Japan’s Fuji Iron Works, this line ensures defect‑free edges and consistent roll quality—critical for automated winding processes in capacitor manufacturing.

Together, the two BOPP capacitor film production lines give Dafu a combined annual capacity approaching 5,000 tons, making it one of the few Chinese manufacturers capable of delivering both sequentially stretched and simultaneously stretched capacitor film. This dual‑technology capability allows Dafu to serve a broader range of customer specifications, from cost‑sensitive commodity grades to high‑end, ultra‑thin film for high‑temperature and high‑frequency applications.

Technical Superiority of Dafu’s BOPP Capacitor Film

What distinguishes Dafu’s ultra‑thin capacitor film from competitors is its balanced combination of electrical, mechanical, and thermal properties—all essential for reliable operation in harsh environments.

• Thickness uniformity is maintained within exceptionally tight tolerances, thanks to advanced gauge control systems on the Brückner lines. This ensures consistent capacitance values and minimises voltage stress concentrations.
• Transverse flatness is excellent, preventing wrinkling during metallisation and winding.
• High dielectric strength (typically > 600 V/μm) enables thinner film designs without sacrificing breakdown voltage, allowing capacitor manufacturers to achieve higher energy density.
• Low dielectric loss (tan δ < 2 × 10⁻⁴) ensures minimal heat generation under high‑frequency ripple currents, improving overall system efficiency.
• High tensile strength in both machine and transverse directions gives the film excellent mechanical stability during high‑speed metallisation and capacitor winding.
• Isotropy is carefully controlled, so electrical and mechanical properties are nearly identical in all directions—a key advantage over conventional capacitor film.
• Heat resistance reaches 105 °C for standard grades, with special formulations extending to 115 °C and 125 °C. Low thermal shrinkage (< 2 % at 105 °C) prevents dimensional changes during capacitor encapsulation and soldering.

These properties are achieved through a combination of premium raw materials—sourced from Borealis, Korea Petrochemical, and other top‑tier suppliers—and rigorous process control. Dafu’s BOPP capacitor film is available in thickness steps from 2.4 μm up to 8 μm, with slitting widths customised to 620 mm, 920 mm, 1,040 mm, or any other customer‑specified dimension.

Critical Applications: Where Ultra‑Thin Capacitor Film Excels

The superior performance of Dafu’s BOPP capacitor film makes it the dielectric of choice for a wide array of demanding applications:

Electric Vehicles (EVs and HEVs) – DC‑link capacitors in traction inverters require high ripple current capability, low equivalent series resistance (ESR), and long lifetime under 105 °C operation. Dafu’s 2.4 μm and 3 μm capacitor film enables compact, lightweight capacitor designs that fit within the limited space of an EV power module, while delivering the required voltage endurance (up to 800 V systems).

Wind and Solar Power – Inverters for photovoltaic and wind turbine systems must handle fluctuating DC voltages and high‑frequency switching. Ultra‑thin BOPP capacitor film with low dielectric loss reduces self‑heating, extending capacitor life and improving overall system reliability—especially critical in remote or offshore installations.

Flexible DC Transmission (HVDC) – High‑voltage DC transmission requires robust capacitors for smoothing and filtering. Dafu’s film offers the high dielectric strength and stable capacitance over temperature that are essential for long‑duration, high‑reliability grid applications.

Composite Current Collectors – In emerging battery technologies, ultra‑thin capacitor film is used as a substrate for metallised current collectors, taking advantage of its excellent surface smoothness and adhesion properties.

High‑Frequency Industrial Controls – Welding equipment, plasma generators, and induction heating systems all benefit from the low‑loss, high‑frequency performance of Dafu’s BOPP capacitor film.

Uncompromising Quality Assurance

Dafu’s commitment to quality is embedded at every stage of production. The company operates a Class 10,000 cleanroom environment with real‑time temperature and humidity monitoring, minimising contamination and ensuring consistent film quality. From incoming raw material inspection to in‑process monitoring and final product release, each batch of BOPP capacitor film undergoes exhaustive testing.

The on‑site laboratory is equipped with advanced instruments: German MAHR thickness gauges for micron‑level accuracy, roughness testers for surface profile analysis, high‑temperature voltage withstand testers, precision high‑voltage bridge capacitors for dielectric measurement, digital high‑resistance meters, electronic tensile testers, and electrical weak‑spot detectors. This comprehensive testing infrastructure guarantees that every roll of capacitor film meets or exceeds international standards, including IEC 60243‑1 for dielectric strength and IEC 60674‑1 for plastic films.

Innovation Leadership and Industry Recognition

Dafu New Materials is not just a manufacturer; it is a technology driver. As a nationally accredited High‑Tech Enterprise and a Guangdong Provincial “Specialised and Sophisticated” SME, the company has actively contributed to industry standards. It led the development of the Chinese national standard for polycarbonate film and sheet (GB/T35450‑2017) and initiated the group standard for PEEK film technical requirements. With 24 invention patents and 16 utility model patents, Dafu continuously pushes the boundaries of polymer film processing, including proprietary formulations for improved heat resistance and reduced shrinkage.

The company’s R&D strength is anchored by the Guangdong Provincial Engineering Technology Research Center for High‑Performance Engineering Plastic Films, which fosters close collaboration with universities and research institutes. This innovation ecosystem ensures that Dafu’s BOPP capacitor film evolves in tandem with emerging customer needs—whether it’s even thinner gauges (targeting < 2 μm), higher temperature ratings, or improved adhesion for metallisation.

A Reliable Partner for the Global Capacitor Industry

With the global BOPP capacitor film market projected to grow at 3.3 %–6.8 % CAGR through 2032, reaching an estimated value of over USD 2 billion, Dafu is strategically positioned to serve both domestic and international customers. The company’s dual‑line capacity, world‑class equipment, and vertically integrated quality system provide supply security, consistent product quality, and rapid response to custom orders.

Moreover, Dafu’s location in the Pearl River Delta—a major electronics manufacturing hub—offers logistical advantages for fast delivery to customers across Asia, Europe, and the Americas. The company’s sales and technical support teams are ready to assist with grade selection, application advice, and joint development of next‑generation capacitor solutions.

Conclusion: The Future is Thin, Reliable, and High‑Performance

As power electronics continue to shrink in size while growing in power, the role of ultra‑thin BOPP capacitor film becomes ever more critical. Dafu New Materials, with its pioneering dual‑line Brückner assets, robust quality systems, and deep application know‑how, is a trusted partner for capacitor manufacturers seeking to differentiate their products. Whether for electric vehicles, renewable energy, or industrial drives, Dafu’s capacitor film delivers the performance, reliability, and consistency that today’s demanding applications require.

We invite OEMs, capacitor makers, and system integrators to explore our full range of BOPP capacitor film products. Visit our facility, discuss your technical requirements, and experience the Dafu difference—where innovation meets precision, and every roll of capacitor film is built to perform.