Composite Polyester Film

SIDA Composite Polyester Film is a premium multilayer electrical insulation material combining polyester film layers with specialized adhesives to create a unified composite structure. Designed for demanding applications in dry-type transformers, motors, and electrical equipment, it delivers outstanding dielectric strength, thermal performance, and long-term reliability.

Description

Technical Overview

Material Construction

SIDA Composite Polyester Film utilizes a multilayer architecture where biaxially oriented polyethylene terephthalate (BOPET) film layers are permanently bonded with proprietary electrical-grade adhesives. This construction method creates a unified composite structure that combines the strengths of individual layers while eliminating common failure modes associated with loosely laminated materials.

The biaxially oriented polyester film base provides excellent tensile strength, dimensional stability, and dielectric properties. The specialized adhesive system is formulated specifically for electrical applications, maintaining its properties under thermal stress, electrical fields, and mechanical loads. Unlike mechanical laminations, our bonded composite structure prevents delamination and ensures consistent performance throughout the material’s service life.

Key Performance Characteristics:

Electrical Properties: High dielectric strength prevents voltage breakdown, low dielectric loss minimizes energy dissipation, excellent resistance to corona and partial discharge, and stable electrical properties across wide temperature ranges.

Thermal Properties: Class F temperature index (155°C continuous operation), maintains properties through thermal cycling, resists thermal aging and degradation, and is compatible with standard vacuum pressure impregnation (VPI) processes used in transformer and motor manufacturing.

Mechanical Properties: High tensile strength and tear resistance withstand installation and operational stresses, excellent dimensional stability prevents warping or shrinkage, flexibility allows easy forming around coils and complex shapes, and resistance to mechanical abrasion protects against installation damage.

Chemical Properties: Resistant to oils, solvents, and transformer fluids commonly encountered in electrical equipment, low moisture absorption (less than 0.1%) maintains electrical properties in humid environments, compatible with epoxy and polyester impregnating resins, and RoHS and REACH compliant formulation meets international environmental regulations.

Quality Assurance

Every production batch undergoes comprehensive quality control testing including electrical testing for dielectric breakdown voltage per ASTM D149, physical testing for thickness uniformity and adhesion strength, thermal testing for heat resistance and aging characteristics, and visual inspection for surface quality verification. Manufactured under ISO 9001:2015 quality management systems and compliant with IEC 60674 and IEC 60641 international standards, SIDA Composite Polyester Film meets the demanding requirements of global electrical equipment manufacturers.


Technical Data Sheet

Product name: Polyester film                                      Thickness:0.05mm                                                                   Test time: 2026.1
No. Test performance/project Unit Test Result Test Method
1 Thickness Average thickness measurement um 50.64 GB/T  13542.2-2021
Average thickness measurement deviation % 1.28
2 Mechanical character Tensile strength MD Mpa 192 GB/T  13542.2-2021
CMD 228
Break elongation MD % 160 GB/T  13542.2-2021
CMD 133
Coefficient of friction Static friction / 0.35 GB/T  10006-1988
Dynamic friction 0.39
3 Dimensional stability Heat shrinkage MD % 1.18 GB/T13542.2-2021(150℃,30min)
CMD -0.15
4 Optical property Light Transmission % 88.64 ASTM D 1003
Haze % 2.14
Gloss 45 GU 130 GB  8807-1988
5 Surface treatment Surface Tension Mn/M 56 GB/T 13542.2-2021
6 Detection conditions Temperature 23 /
Relative humidity % 46
Test result: Pass

Note:The product specifications provided are for reference purposes only. Please refer to the actual product for final specifications. We also offer various sizes and thicknesses to meet your specific needs. For further customization, please contact us.


Application Scenarios

Dry-Type Transformer Insulation

SIDA Composite Polyester Film provides essential insulation for dry-type transformers in multiple critical applications:

Primary Applications:

  • HV/LV Coil Insulation: Main barrier between high voltage and low voltage windings, with 25-30kV breakdown voltage providing substantial safety margins
  • Layer Insulation: Between winding layers to prevent turn-to-turn shorts while maintaining compact designs
  • Phase Insulation: Reliable isolation between phases in three-phase transformers
  • Ground Wall Insulation: Primary insulation from windings to grounded core structures

The material’s Class F thermal rating (155°C) ensures reliable performance in transformer hot-spot regions, while dimensional stability maintains consistent insulation gaps throughout operational life.

Motor & Generator Insulation

Critical insulation applications in rotating electrical machines:

Key Applications:

  • Slot Insulation: Lines stator and rotor slots, protecting windings from laminated core edges while providing electrical isolation
  • Turn Insulation: Prevents inter-turn short circuits with uniform thickness and minimal space consumption
  • Phase Insulation: Separates phase windings, maintaining isolation under vibration and thermal cycling
  • Liner Insulation: Additional protection under slot wedges and in high-stress coil end regions

The material’s tear resistance withstands winding insertion operations, while high dielectric strength ensures reliable operation.

Industrial Electrical Equipment

Additional applications include:

  • Reactors & Inductors: Interlayer insulation for power quality and harmonic filtering applications
  • Busbar Systems: Compact insulation for switchgear and control panels
  • Terminal Barriers: Insulating barriers in electrical enclosures preventing phase-to-phase faults
  • Capacitors: Dielectric reinforcement in power capacitor construction
  • General Equipment: Control transformers, electrical cabinets, and custom electrical assemblies

Frequently Asked Questions

Q1: How do I choose between 0.5mm and 1.10mm thickness?

Selection depends on your voltage rating, mechanical requirements, and space constraints. For equipment rated up to 6kV class, the 0.5mm thickness typically provides adequate breakdown voltage (≥25kV) with minimal space consumption. For 10kV class equipment and above, or applications requiring additional mechanical reinforcement, the 1.10mm thickness (≥30kV breakdown voltage) is recommended. The thicker material also provides better handling characteristics during installation and greater resistance to mechanical damage. Our technical team can assist with voltage stress calculations for your specific application.

Q2: Can this material be used with vacuum pressure impregnation processes?

Yes, SIDA Composite Polyester Film is fully compatible with VPI processes commonly used in motor and transformer manufacturing. The material withstands vacuum conditions without delamination and allows complete resin penetration. The adhesive system remains stable during typical VPI thermal cycles (130-150°C). After impregnation, the composite maintains its dimensional stability and electrical properties, creating a robust insulation system when combined with impregnating resins.

Q3: What is the shelf life and how should the material be stored?

When stored properly, the material maintains its specified properties for 12 months from the manufacturing date. Store in original moisture-proof packaging in a clean, dry environment at temperatures between 15-30°C and relative humidity below 60%. Avoid direct sunlight exposure and keep away from chemical solvents. Before use, allow materials stored in different temperature conditions to acclimate to room temperature for at least 24 hours while still in sealed packaging to prevent condensation.

Q4: Is this material compatible with different transformer and motor manufacturing processes?

SIDA Composite Polyester Film is designed for compatibility with standard manufacturing processes including manual winding operations, automated coil winding machines, die-cutting for precision shapes, and both wet and dry insulation systems. The material can be cut, formed, and installed using conventional equipment and techniques. It is compatible with common impregnating resins including epoxy, polyester, and silicone formulations used in transformer and motor manufacturing.

Q5: What testing standards does this product comply with?

Our composite polyester film is manufactured and tested according to international standards including IEC 60674 (specifications for plastic films for electrical purposes), ASTM D149 (dielectric breakdown voltage testing), and relevant sections of IEC 60641 (testing methodologies). The material is produced under ISO 9001:2015 certified quality management systems. Complete test reports documenting electrical, mechanical, and thermal properties are available for each production lot, providing full traceability for quality assurance purposes.


Quality Commitment

SIDA is committed to delivering consistent, high-quality electrical insulation materials that meet the demanding requirements of modern electrical equipment manufacturing. Our composite polyester film is produced in ISO 9001:2015 certified facilities using advanced manufacturing processes and comprehensive quality control procedures. Every roll is traceable from raw materials through finished product, ensuring complete quality documentation for your certification and qualification requirements.

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Phone

+86 15958243831

Email

jessie.feng@sidanm.com

Address

YiTian Building. 850 ChengXin Road,Yinzhou,Ningbo,China,315100

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