What is a polyimide film?

Part 1: What is Polyimide Film?

Polyimide (PI) refers to a polymer containing an imide structure in the main chain of the molecular structure. Polyimide is a very large family. The main chain of high-performance PI mostly uses aromatic rings and heterocyclic rings as the main structural units.

 

PI has the highest flame retardant rating (UL-94), good electrical insulation, mechanical properties, chemical stability, aging resistance, radiation resistance, a dielectric constant of 4.0 at 103 Hz, and a dielectric loss of only 0.004 to 0.007, which belongs to F to H grade insulation. These properties will not change significantly in a wide temperature range (-269℃ to 400℃).

 

It is known as "one of the most promising engineering plastics in the 11th century" and is known as a "problem solver". It can be said that "without polyimide, there would be no microelectronics technology today". Its performance is at the top of the pyramid of polymer materials.

 

Part 2: Types of Polyimide Films & Their Applications

2.1 Standard Polyimide Films

Thickness: 12.5–125 microns (±5% tolerance).

Key Features:

Balanced thermal and mechanical performance.

Cost-effective for general-purpose use.

Applications:

Flexible printed circuits (FPCs).

Motor and transformer insulation.

 

2.2 High-Temperature PI Films

Thickness: 25–200 microns.

Key Features:

Enhanced thermal stability (up to 500°C short-term).

Low thermal expansion coefficient (CTE: 20–50 ppm/°C).

Applications:

Aerospace engine components.

Industrial heating element barriers.

 

2.3 Conductive PI Films

Structure: PI film coated with conductive layers (e.g., copper, silver).

Key Features:

Surface resistance: 0.1–10 Ω/sq.EMI shielding effectiveness: ≥30 dB.

Applications:

Flexible heaters.Antistatic packaging for electronics.

 

2.4 Adhesive-Backed PI Films

Structure: PI film laminated with silicone or acrylic adhesives.

Key Features:

Peel strength: 5–20 N/cm.Temperature resistance: -60°C to 260°C.

Applications:

High-temperature masking tapes.Thermal management in LED lighting.

Part 3: Key Applications of Polyimide Films

3.1 Electronics & Semiconductors

Flexible Circuits: Replaces rigid PCBs in smartphones, wearables.

Chip Packaging: Insulates microchips from heat and moisture.

 

3.2 Aerospace & Defense

Wire & Cable Insulation: Protects wiring in jet engines and satellites.Thermal Blankets: Shields spacecraft from extreme temperatures.

 

3.3 Automotive

Electric Vehicle Batteries: Separates cells and prevents thermal runaway.Under-the-Hood Sensors: Withstands oil and heat in engines.

 

3.4 Industrial Equipment

Insulating Barriers: Used in motors, generators, and power tools.

High-Temperature Gaskets: Seals industrial furnace components.

 

Part 4: Material Compatibility – Combining PI Films with Other Materials

PI films are often combined with other materials to enhance functionality:

 

4.1 PI + Copper Foil

Structure: PI film laminated with rolled or electrodeposited copper.

Applications: Flexible circuits, RFID antennas.

Benefits:

Bendability without cracking (tested for 10,000+ flex cycles).

Stable impedance for high-frequency signals.

 

4.2 PI + Adhesives

Common Adhesives: Silicone, epoxy, acrylic. Applications: Thermal tapes, EMI shielding.

Benefits:

Bonds to metals, ceramics, and plastics. Maintains adhesion under thermal cycling.

 

4.3 PI + Ceramic Fillers

Structure: PI composite with alumina or silica particles.Applications: Heat sinks, insulating substrates.

Benefits:

Thermal conductivity: 1–5 W/m·K.Reduced CTE for dimensional stability.

 

Part 5: Advantages of Our Polyimide Films

5.1  Quality Control

Material Sourcing: High-purity monomers from suppliers.

Precision Manufacturing:

Thickness tolerance: ±3% (measured via laser micrometers).Surface roughness: ≤0.1 µm for smooth coating adhesion.

Testing Protocols:

Thermal Gravimetric Analysis (TGA): Confirms degradation temperature (≥500°C).Dielectric Strength: Tested at 2x rated voltage (e.g., 200 kV/mm for 100 µm film).

 

5.2 Customization Flexibility

Tailored Solutions:

Custom thickness (12.5–250 µm).

Slit widths from 5mm to 1,500mm (±0.2mm tolerance).

Perforations, embossing, or printed alignment marks.

Low MOQs:

Standard films: 50 kg.

Custom grades: 100 kg.

 

Part 6: Why choose us?

6.1 Quality Assurance & Certifications

Global Standards: UL 94 V-0 (flammability), RoHS, REACH, IPC-4203 (flex circuits).

Traceability: Batch-specific QR codes linked to test reports (TGA, FTIR, tensile tests).

 

6.2 Supply Chain Reliability

Lead Times:

Stock items: 10–15 days.

Custom orders: 20–30 days.

Global Logistics:

Warehouses in China, Germany, and the USA.

Air/sea freight with real-time tracking.