Electrical Insulators
Transfers heat while providing electrical isolation between components and metal cooling structures. Select by installation form, thickness, insulation strength, mechanical strength and operating environment.
Thermally Conductive Insulator Selection Guide
Do not select a thermally conductive insulator solely by whether it insulates. Also compare the installation structure, thickness, thermal resistance, withstand voltage, puncture resistance, handling and operating environment. Caps and sleeves cover specific components, while polyimide and fiberglass materials suit thin, flat or custom-cut interfaces.
Confirm the Installation Form
Thermally conductive insulators are available as three-dimensional covers or flat insulation sheets. Select the form according to the component shape, heat sink structure and assembly method.
- Transistor or power-component shape
- Flat contact or three-dimensional coverage
- Need for component positioning
- Heat sink-to-component contact method
- Installation space and working direction
Do not select a cap or sleeve by component name alone. Confirm the package dimensions, thickness and heat sink structure. For flat materials, check the cut profile and hole-position tolerances.
Check Operating Voltage and Insulation
Confirm sufficient electrical isolation based on the equipment operating voltage, safety clearances and regulatory requirements.
- Dielectric breakdown voltage
- Dielectric breakdown
- Volume resistivity
- Actual material thickness
- Creepage and clearance distances
Dielectric strength is generally expressed per unit thickness and is not the finished part’s withstand voltage. Evaluate the actual thickness, processed condition and safety factor.
Compare Thickness and Thermal Resistance
A thinner material generally shortens the heat-transfer path, but thickness also affects insulation, puncture resistance and the ability to accommodate surface tolerances.
- Original material thickness
- Actual contact thermal resistance
- Surface flatness
- Insulation safety margin
- Contact condition after assembly
Thinner is not always better. With an excessively thin material, burrs, metal protrusions and uneven fastening pressure may increase the risk of puncture and insulation failure.
Select the Material Structure
Polyimide and fiberglass composites have different selection priorities. Evaluate thinness, temperature resistance, mechanical strength and processing requirements.
- Polyimide film structure
- Fiberglass-reinforced structure
- Silicone or non-silicone formulation
- Thermally conductive surface coating
- Single-layer or composite structure
Polyimide emphasizes thinness, temperature resistance and electrical insulation. Fiberglass emphasizes reinforcement and puncture resistance. Materials with the same name may have very different thermal resistance because of different coatings and composite structures.
Assess Mechanical Strength and Contact Surfaces
Metal burrs, screw holes, rough surfaces and concentrated pressure may damage the material or puncture the insulation layer.
- Tensile and tear strength
- Puncture resistance
- Metal-surface roughness
- Fastening pressure and uniformity
- Edge and hole strength
Datasheet insulation values are generally obtained from intact specimens. Die-cut burrs, creases, misaligned holes and metal protrusions may reduce actual insulation performance.
Assess Application and Handling
Caps and sleeves can be fitted directly for positioning. Flat sheets are available with different tack, release liners and custom die-cut options.
- Fitting or adhesive application
- Single-sided, double-sided, or non-adhesive
- Release liner and pull-tab design
- Manual or automated assembly
- Disassembly and rework requirements
Tack mainly supports positioning during assembly and does not necessarily improve heat transfer. Excessive tack may complicate rework and damage the insulation layer during removal.
Check Temperature and Operating Environment
The material must maintain stable heat transfer and insulation under prolonged high temperatures, thermal cycling, humidity, vibration and contamination-sensitive conditions.
- Long-term operating temperature
- Thermal cycling
- High temperature and humidity
- Vibration and mechanical shock
- Vacuum, sealed or clean environments
- Contact with chemicals and coolants
Maximum temperature resistance is only an initial screening value. Confirm dielectric strength, dimensions, embrittlement, delamination and thermal-resistance changes after aging.
Check Flame-Retardant and Certification Requirements
For power, automotive and industrial equipment or other safety-regulated applications, confirm the test and certification data for the specified thickness and material model.
- UL flammability rating
- Certified thickness range
- RoHS／REACH
- Halogen-free requirements
- Automotive or industrial reliability requirements
UL certification generally applies to a specific material, thickness and operating condition. Certification of one product does not mean the entire series has the same certification.
Quick Selection Guide
| Application | Recommended Category / Material |
|---|---|
| Three-dimensional coverage for transistors and power components | Caps / sleeves |
| Fast fitting with less manual alignment | Caps / sleeves |
| Very small gaps and thin cooling structures | Polyimide |
| High-temperature environments and thin insulation | Polyimide |
| Metal burrs or concentrated pressure | Fiberglass reinforcement |
| Large areas, holes or custom die-cut shapes | Fiberglass reinforcement |
| Contamination-sensitive or optical equipment | Non-silicone, low-outgassing grade |
| Power and safety-compliance applications | Flame-retardant / UL-certified grade |
Choose the Right Thermally Conductive Insulator
Polyimide film and fiberglass-reinforced structures combine heat transfer, electrical insulation and mechanical strength. Select according to thinness, low thermal resistance, high-temperature resistance, puncture resistance and die-cutting requirements. Suitable for flat interfaces and complex profiles.
Thin and Low Resistance
reduces the distance from component to heat sink.
Electrical Isolation
Isolates live components from metal cooling structures.
Thermal Stability
Suits prolonged high temperatures and thermal cycling.
Reinforced Structure
Fiberglass improves tensile and puncture resistance.
Custom Die Cutting
Supports holes, custom shapes and large-area processing.
Confirm the Material
Select by thickness, temperature resistance, insulation and puncture resistance.
Clean the Surfaces
Remove metal debris, dust, oil and sharp protrusions.
Remove the bottom liner
Remove the first release liner according to the product structure.
Align and place
Align with the component, holes and heat sink, then apply flat.
Assemble and Inspect
Fasten evenly and check for wrinkles, damage or displacement.
Power modules
MOSFET／IGBT
battery management systems
motor and inverter controls
automotive electronics
industrial computers
A preformed three-dimensional structure covers transistors and power components, forming a stable thermally conductive insulation layer between the component and metal heat sink. It reduces sheet alignment, washer handling and installation displacement, making it suitable for repetitive assembly.
Three-Dimensional Coverage
Fully isolates the component from the metal cooling structure.
Fast Fitting
Reduces sheet, washer and hole-alignment steps.
Stable Positioning
Resists slipping during fastening and assembly.
Flexible Conformity
Conforms to the component and accommodates local tolerances.
Custom Forming
Designed to match package dimensions and structural requirements.
Confirm Specifications
Check the component package, cap dimensions and thickness.
Clean the Surfaces
Remove oil and foreign matter from the component and heat sink.
Fit the Cap
Fully cover the component in the correct direction.
Position Against the Heat Sink
Confirm that the cap is flat, untwisted and unfolded.
Fasten and Inspect
Apply even fastening pressure and check for extrusion or puncture.
power transistors
MOSFET／IGBT
Power modules
motor and inverter controls
inverters
industrial control equipment
Feature Overview
Non-Silicone
Reduce Siloxane Outgassing and Contact Contamination
Evaluate material outgassing, condensable substances and water-vapor regain to reduce the risk of contaminating lenses, sensors and precision components in vacuum or sealed environments.
High Insulation
Reliable Electrical Isolation at the Thermal Interface
High volume resistivity and dielectric strength provide electrical isolation between live components and metal heat sinks. Select the appropriate specification according to the operating voltage, material thickness and required safety factor.
Thin and Low Resistance
Shorter Heat-Transfer Path with Space-Efficient Insulation
Thin polyimide or composite materials reduce the heat-transfer distance. Suitable for electronic modules with limited gaps, compact structures and electrical-isolation requirements.
Reliability
Stable Under Heat and Thermal Cycling
Heat-resistant films and composite structures reduce embrittlement, shrinkage and insulation degradation caused by prolonged exposure to high temperatures. Suitable for power components and industrial equipment.
Puncture-Resistant Reinforcement
Protection Against Damage from Burrs and Concentrated Pressure
Fiberglass reinforcement improves tensile strength, tear resistance and puncture resistance. Suitable for perforated die-cut parts, rough metal surfaces and structures exposed to high fastening pressure.
Flame Retardancy / UL Certification
Meets Safety Requirements for Power and Industrial Equipment
Specified flame-retardant or UL-certified grades are available; verify the model and thickness.
Thermally Conductive Insulator FAQs
How Do Caps and Sleeves Differ from Flat Insulation Sheets?
Caps and sleeves are preformed three-dimensional structures that directly cover specific components for fast, stable positioning. Flat materials are thinner and offer greater cutting flexibility for flat interfaces, large areas and custom shapes.
How Should Polyimide and Fiberglass Materials Be Selected?
Consider polyimide when thinness, high-temperature resistance and lower thermal resistance are priorities. Consider fiberglass reinforcement for surfaces with burrs, higher fastening pressure, large areas or complex die-cut shapes.
Does higher thermal conductivity always mean better cooling?
Not necessarily. Actual cooling also depends on thickness, contact thermal resistance, surface flatness and fastening pressure. A thin, well-conformed material may outperform a thicker material with higher conductivity.
Is a Thinner Thermally Conductive Insulator Always Better?
No. A thinner material may reduce thermal resistance but can also reduce puncture resistance and the insulation safety margin. Burrs, protrusions or uneven pressure may make an excessively thin material more likely to fail.
Can Dielectric Strength Be Used Directly as Withstand Voltage?
No. Dielectric strength is measured per unit thickness. Actual withstand voltage also depends on thickness, processed edges, humidity, aging and the safety factor.