TF-BOPP-6um-100mm

BOPP (biaxially oriented polypropylene) and PET (polyethylene terephthalate) are both used for film capacitors but have different characteristics. BOPP has lower dielectric constant (2.2 vs 3.3) which results in lower capacitance density but also lower dissipation factor and better high-frequency performance. BOPP is preferred for AC applications and high-frequency filtering. PET has higher dielectric constant, providing higher capacitance density, and higher temperature rating (up to 125C vs 105C for BOPP). PET is preferred for DC applications and higher temperature environments. BOPP is generally lower cost and has better self-healing properties. For most AC motor and power electronics applications, BOPP is the preferred choice.

Choose BOPP for AC applications, high-frequency filtering, and cost-sensitive designs. Choose PET for DC applications, higher temperature requirements, and when maximum capacitance density is needed.

Heavy edge metallization refers to a thicker aluminum layer at the edge of the metallized film where the end spray contact is made. Standard metallization thickness is typically 8-15nm, while heavy edge metallization may be 20-40nm or more at the edge. This thicker edge provides several benefits: Lower contact resistance between the film and end spray, reducing ESR and heating. Improved current handling at the contact point. Better mechanical strength at the edge to prevent tearing during winding. More consistent electrical connection over the capacitor lifetime. Heavy edge design is particularly important for capacitors with high ripple current requirements, such as DC-link capacitors and motor run capacitors. Tongfeng's heavy edge films provide excellent performance in these demanding applications.

For high current applications, always specify heavy edge metallization. Contact us for specific heavy edge thickness recommendations based on your current requirements.

Film thickness selection depends on the voltage rating and application requirements. Thinner films (4-6um) provide higher capacitance density (more capacitance per volume) but lower voltage rating. Thicker films (8-12um) provide higher voltage rating but lower capacitance density. A general guideline is to use 4-5um for low voltage applications (<250V), 6-8um for medium voltage (250-450V), and 10-12um for high voltage (>450V). The dielectric strength of BOPP is approximately 400V/um, so a 6um film can theoretically withstand 2400V, but practical designs use 30-50% of this value for safety margin and lifetime considerations. For AC applications, consider the peak voltage (1.414 × RMS voltage) when selecting film thickness.

Contact our FAE team with your voltage rating, application type, and size constraints for film thickness selection recommendations.

Metallized films have a shelf life of typically 12-24 months when stored in proper conditions. Storage recommendations include: Temperature: 5C to 35C, ideally 20-25C. Humidity: 40-60% RH, avoid high humidity which can affect metallization. Protection from direct sunlight and UV exposure. Storage in original packaging until use. Avoid storage near corrosive chemicals or gases. Beyond the shelf life, the film may still be usable but should be tested for metallization adhesion and electrical properties before use. Films stored in high humidity may show oxidation of the aluminum metallization, which increases resistance and can affect capacitor performance. Always check the manufacturing date on the film packaging and use FIFO (first in, first out) inventory management.

Store films in controlled conditions and use within recommended shelf life. Contact us for specific storage recommendations and shelf life information.

Yes, Tongfeng offers customization options for metallized films including custom widths, metallization patterns, and margin configurations. Custom options include: Film widths from 20mm to 400mm. Segmented metallization patterns for specific capacitor designs. Custom margin widths for different voltage requirements. Different metallization thicknesses (light, standard, heavy). Tapered metallization for graded voltage distribution. Custom roll lengths and packaging. Minimum order quantities apply for custom specifications, typically 1000-5000kg depending on the customization. Lead times for custom films are typically 4-8 weeks. For standard sizes and specifications, off-the-shelf availability is better with shorter lead times.

Contact us with your specific film requirements for custom quotation and lead time information.

Tongfeng applies comprehensive quality controls to metallized films including: Raw material testing - polypropylene resin quality and consistency. Film thickness measurement - continuous monitoring during extrusion and stretching. Metallization thickness measurement - optical density monitoring during metallization. Margin accuracy - visual and automated inspection. Dielectric strength testing - sample testing from each batch. Mechanical property testing - tensile strength and elongation. Metallization adhesion testing - tape test and electrical resistance. Visual inspection - for defects, pinholes, and contamination. Each batch is traceable with certificates of analysis provided. Statistical process control ensures consistent quality from batch to batch.

Tongfeng's comprehensive quality control ensures consistent film quality for reliable capacitor manufacturing. Contact us for quality certifications and test reports.