In the world of thermal interface materials (TIMs), silicone-based pads have long been favored for their compliance, stability, and durability. But one persistent drawback is silicone oil migration (often called oil bleed). Over time and under thermal stress, the internal silicone oil can migrate to surfaces or components, risking contamination, latent short circuits, or interference — especially when your system includes silicone-sensitive parts such as optical sensors or adhesives.
T-Global’s Low Bleed series — TG-A5000L, TG-A3200L, and TG-A1800L — is designed to mitigate that risk while preserving the advantages of silicone-based thermal pads. Importantly, “low bleed” does not mean “silicone-free.” These pads are still silicone-based but engineered to minimize oil separation over time.
Overview of TG-A5000L / A3200L / A1800L
These three thermal pad grades give designers the ability to select the right balance of conductivity, softness, and long-term stability:
| Product | Thermal Conductivity | Highlights / Notes |
|---|---|---|
| TG-A1800L | ~1.8 W/m·K | Entry-level thermal conductivity with excellent mechanical compliance and controlled oil bleed. |
| TG-A3200L | ~3.2 W/m·K | Balanced performance between conductivity and softness; a versatile choice for general electronics. |
| TG-A5000L | ~5.0 W/m·K | Highest conduction option among the trio; ideal for higher heat flux paths. |
All three are available in a broad range of thicknesses and maintain good dielectric performance while resisting oil migration. In addition, all these pads come with tack on both sides to aid in assembly.
Why Silicone Oil Separation Is a Concern
What is Oil Bleed?
Oil bleed is the migration of low-molecular-weight silicone fluid out of a thermal pad when exposed to heat, pressure, or long operating life. This phenomenon can:
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Contaminate optical surfaces and sensors
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Interfere with silicone adhesives or gels
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Create leakage paths or potential shorts if it reaches conductive areas
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Degrade adhesion or mechanical stability
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Cause unsightly smears or drips during long-term use
In optoelectronics, MEMS, and automotive electronics, even small amounts of oil can compromise function or reliability.
Why It’s Not “Silicone-Free”
Low bleed doesn’t mean the pads aren’t silicone-based — they still rely on silicone polymers to deliver softness, resilience, and thermal stability. Instead, these pads use improved polymer crosslinking and fillers to trap and stabilize oils, reducing migration dramatically while maintaining the benefits of silicone.
Use Cases and Design Considerations
These low-bleed pads are excellent for:
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Optical and camera modules where lenses or sensors must stay clean
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MEMS and microdevices that require uncontaminated surfaces
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Consumer and wearable electronics where long life and cleanliness matter
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Automotive modules that endure vibration and thermal cycling
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Telecom and power electronics needing stable, high-performance TIMs
When selecting between the grades:
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Choose TG-A5000L for high power density or tight thermal budgets.
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Choose TG-A3200L for balanced performance and cost.
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Choose TG-A1800L for lower thermal needs but maximum compliance and stability.
Other considerations include pad thickness, temperature range, dielectric insulation, and assembly pressure.
Best Practices for Minimizing Oil Migration
To get the most from low-bleed silicone pads:
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Avoid direct contact with sensitive optics or seals where possible
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Apply controlled, even compression — avoid point loads
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Validate with thermal cycling tests before full production
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Keep interfaces clean and dry during assembly
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Select the thinnest pad thickness practical for your design
Conclusion
T-Global’s TG-A5000L, TG-A3200L, and TG-A1800L deliver the trusted thermal performance of silicone pads while dramatically reducing oil bleed — a key reliability upgrade for sensitive electronics. They are not silicone-free; rather, they are advanced silicone materials tuned for long-term stability.
For engineers balancing heat, compliance, and reliability, these pads provide an effective way to maintain performance and protect delicate components from oil migration over the life of the product. NEDC does custom die cutting, and waterjet cutting for customers for thermal pads.