Insulation Fish Paper with Film: Ultimate Composite Solution

For global motor manufacturers, transformer producers, and electrical equipment OEMs, sourcing reliable insulation fish paper with film is critical for performance and safety. The most competitive and technically advanced supply for this composite material is concentrated among specialized exporters in the global manufacturing hub. This definitive 2026 guide provides the technical knowledge and strategic framework you need to identify, evaluate, and partner with the right supplier to secure high-quality, compliant materials for your production.

Specification of Insulation Fish Paper with Film

Base layer: Insulation fish paper

Film layer: Transparent polyester film (PET film)

Adhesive: An acid-free, temperature-resistant adhesive bonds the layers.

Insulation fish paper with PET film is a precision-engineered composite. The cellulose-based fish paper(presspaper) provides excellent mechanical strength and formability, serving as a robust base. The laminated transparent polyester film (PET) is not a simple coating; it is a continuous, inseparable barrier that fundamentally upgrades the material's performance. This combination is specifically designed for demanding applications like EV motor slot liners, high-voltage transformer insulation, and automated stator manufacturing lines where consistency is non-negotiable.

Performance Data: 

The value of this composite lies in its quantifiable superiority. Sourcing standard fish paper will not deliver the necessary reliability for modern, compact designs. The PET film layer directly targets key failure points. For critical evaluation, compare these typical parameters:

• Dielectric Strength: Increases from ~10 kV/mm to >12-16 kV/mm, essential for 800V EV architectures.

• Moisture Resistance: Absorption drops from >5% to <1%, preventing degradation in humid environments.

• Thermal Endurance: Enables consistent performance from Class B (130°C) to Class F (155°C) ratings.

Mechanical Integrity: The film enhances puncture resistance, which is crucial for preventing nicks and tears during high-speed automated motor assembly.

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Application of Fish Paper with Film:

• Electric Motors and Electrical Appliances: Slot insulation, phase insulation, and buffering in low-voltage motors, fans, and other electrical equipment.

• Transformers: Used as interlayer insulation.

• Gaskets: Used for sealing and insulation.

Procuring this material is not merely a cost decision; it is a supply chain strategy. The leading exporters for electrical insulation composites have evolved by serving the world's most volume-intensive and innovation-driven markets. This offers you, as a global buyer, distinct advantages:

1. Integrated Supply Chain: Access to upstream raw materials (PET film, insulating paper) ensures stable supply and shorter lead times.

2. Application-Driven R&D: Suppliers are adept at iterating formulations (e.g., adhesive systems, thickness profiles) to solve specific problems like partial discharge resistance or thermal conductivity.

3. Compliance Infrastructure: Established exporters maintain full UL certification (Yellow Card), RoHS/REACH compliance, and rigorous in-house testing labs aligned with IEC and ASTM standards, simplifying your qualification process.

Your 2026 Supplier Vetting Checklist

To secure a reliable insulation fish paper supplier, due diligence is key. Move beyond datasheets and price with this actionable audit list:

Request and Validate Certifications: Insist on seeing the current UL certificate (File E) and recent third-party test reports (e.g., SGS) for dielectric strength and thermal class.

Assess Technical Dialogue: A competent partner will ask detailed questions about your application, slot fill factor, winding process, and operating environment.

Evaluate Manufacturing Control: Request evidence of their lamination process control and statistical process control (SPC) data for thickness tolerance (aim for ±0.02mm).

Perform a Rigorous Sample Test: Subject their material samples to your full quality assurance protocol, including not just electrical tests but also die-cutting, folding, and compatibility tests with your varnishes.

Conclusion: Building a Partnership for Future-Proof Designs

In 2026, sourcing insulation fish paper with PET film is about forging a technical partnership. The right exporter acts as an extension of your engineering team, ensuring the material is not just a component but a contributor to your motor's reliability and performance. By focusing on suppliers who demonstrate deep export experience, certified quality, and collaborative problem-solving, you secure more than a material—you gain a strategic advantage in a competitive global market. Begin your sourcing process by defining your exact specifications and demanding proof of expertise, not just a quotation.