Thermally Conductive Silicone Gap Filler With Adhesion and Shape Retention
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Solution Overview
Problem
Existing thermally conductive silicone compositions face challenges in achieving a balance between high thermal conductivity, adhesion to substrates, and coating workability, particularly when used as gap fillers for complex shapes, due to issues with viscosity, flexibility, and adhesion, which are not adequately addressed by existing technologies.
Innovation Solution
Incorporating a terpene phenol resin into a thermally conductive silicone composition containing diorganopolysiloxanes with alkenyl and hydrogen atoms, along with a thermally conductive filler and an addition reaction catalyst, allows for improved adhesion and shape retentivity while maintaining thermal conductivity and coating workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermally conductive filler is filled to achieve a high packing density, then the thermal conductivity is improved, but the flexibility of the gap filler is impaired and adhesion at the interface is lowered
Solution Approach 1:
The patent uses a composite material system combining organopolysiloxane base polymer with specific fillers (aluminum nitride and crushed alumina) and additives to achieve both high thermal conductivity and adhesion. The composite formulation allows the filler to provide thermal conduction while the polymer matrix maintains flexibility and bonding capability.
Solution Approach 2:
The patent optimizes the particle size distribution of fillers, specifying that crushed alumina has an average particle diameter of 0.1 μm to 10 μm. This parameter control allows dense packing for thermal conductivity while maintaining sufficient polymer content for adhesion and flexibility.
2Reliability
If aluminum nitride is added to increase thermal conductivity, then the thermal conductivity is improved, but the viscosity of the composition is largely increased and coating workability drops
Solution Approach 1:
The patent controls the average particle diameter of crushed alumina to be within 0.1 μm to 10 μm, which optimizes the balance between thermal conductivity and viscosity. The finer particle size distribution allows better packing efficiency without excessive viscosity increase, improving coating workability while maintaining thermal performance.
Solution Approach 2:
The patent combines aluminum nitride with crushed alumina in a composite filler system, where the alumina component helps modulate the overall viscosity and rheology of the composition, making it more workable during coating while the aluminum nitride provides the primary thermal conduction pathway.
3Strength
If the amount of liquid additive is increased to improve adhesion, then the adhesion is improved, but the viscosity of the composition decreases and bead shape retentivity is impaired
Solution Approach 1:
The patent carefully controls the viscosity of the thermally conductive silicone composition to be within 10 Pa·s to 1000 Pa·s at 25°C. This parameter optimization ensures sufficient adhesion without excessive flow, maintaining bead shape retentivity during application while achieving good interfacial bonding.
4Strength
If an adhesive aid that chemically imparts adhesiveness is used to improve adhesion, then the adhesion is improved, but secondary processing such as heating is required
Solution Approach 1:
The patent formulates the composition to achieve adhesion through its inherent chemical composition (organopolysiloxane base polymer with specific functional groups) rather than requiring additional adhesive aids. The material provides self-adhesion capability through its molecular structure, eliminating the need for secondary heating or chemical treatment processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition exhibits excellent coating workability, shape retentivity, and adhesion to substrates, forming a thermally conductive member with high heat dissipation properties, suitable for use as a gap filler.
Implementation Method 1
a component (A) that is a diorganopolysiloxane having an alkenyl group bonded to a silicon atom; a component (B) that is a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom; and a component (E) that is an addition reaction catalyst
Implementation Method 2
a component (D) that is a thermally conductive filler... excellent heat dissipation properties... high thermally conductive filler typified by aluminum nitride
Data Source
AI summary
Provided is a thermally conductive silicone composition for use as a gap filler, where the thermally conductive silicone composition exhibits excellent coating workability on a substrate and good shape retentivity after coating, is able to be cured to form a thermally conductive member with excellent heat dissipation properties and good adhesion to a substrate such as a heat generating body or a heat dissipation body, and is to be applied in an uncured state to a substrate. The thermally conductive silicone composition contains (A) a diorganopolysiloxane having an alkenyl group bonded to a silicon atom; (B) a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom; (C) a terpene phenol resin; (D) a thermally conductive filler; and (E) an addition reaction catalyst, and the thermally conductive silicone composition is applied in an uncured state to a substrate.