Silicone Grease Composition for Heat Dissipation and EMI Absorption

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Solution Overview

Problem

High-density electronic components face challenges in heat dissipation and electromagnetic interference due to low thermal conductivity and noise transmission, particularly at high-frequency and super-high-frequency ranges, which existing thermally conductive greases fail to adequately address.

Innovation Solution

A silicone composition incorporating a high-specific-gravity soft magnetic filler, an intermediate-specific-gravity thermally conductive filler, and a non-liquid anti-thickening and anti-settling agent, which suppresses noise transmission and enhances heat dissipation by maintaining uniform viscosity and composition, preventing settling of fillers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional thermally conductive grease is used, then heat dissipation is provided, but thermal conductivity is low and air layer formation occurs

Engineering Contradiction:
Improveheat dissipationVSAvoidthermal conductivity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses a composite material system combining silicone rubber base resin with multiple types of fillers (thermally conductive filler, soft magnetic filler, and hollow filler) to create a grease that achieves both high thermal conductivity and electromagnetic wave absorption. This composite approach resolves the contradiction by integrating multiple functional materials that work together to improve heat dissipation while maintaining reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the particle size distribution of fillers, specifying that thermally conductive filler has an average particle diameter of 0.1 to 1.0 μm, and adjusts the composition ratios (thermally conductive filler: 20-40 mass%, soft magnetic filler: 10-30 mass%, hollow filler: 5-20 mass%) to achieve optimal thermal conductivity and prevent air layer formation while maintaining good heat dissipation.

Inventive Principle:
Principle #35Parameter changes

2Speed

If high-frequency components are generated in electronic devices, then processing speed increases, but electromagnetic noise and interference increase

Engineering Contradiction:
Improveprocessing speedVSAvoidelectromagnetic noise
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent incorporates soft magnetic filler (such as ferrite or iron powder) with specific particle size (average particle diameter of 1.0 to 10.0 μm) into the grease composition. This soft magnetic filler provides electromagnetic wave absorption capabilities that suppress high-frequency noise and electromagnetic interference generated by fast-processing electronic components, while the composite structure with hollow fillers enhances the noise suppression effect through multiple interfaces.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for the soft magnetic filler including particle size (1.0 to 10.0 μm average diameter) and content (10-30 mass%), which are optimized to absorb electromagnetic noise in the high-frequency range while minimizing impact on thermal conductivity and maintaining grease functionality.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If filler particles settle in the grease, then composition uniformity decreases, but viscosity increases and heat dissipation deteriorates

Engineering Contradiction:
Improvecomposition uniformityVSAvoidheat dissipation
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent creates a multi-component filler system where hollow filler particles (with average particle diameter of 1.0 to 10.0 μm) are combined with thermally conductive and soft magnetic fillers. The hollow fillers act as spacers that prevent dense packing of heavier filler particles, reducing settlement. The composite structure maintains composition uniformity while preserving thermal conductivity pathways for effective heat dissipation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the particle size distribution across all filler types, ensuring that the hollow filler has comparable or larger particle diameter than the thermally conductive filler (0.1 to 1.0 μm). This parameter optimization prevents smaller, denser particles from settling while maintaining good dispersion and thermal conduction, thus preventing viscosity increase and heat dissipation deterioration.

Inventive Principle:
Principle #35Parameter changes

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 silicone composition effectively suppresses noise transmission across a wide frequency range and improves heat dissipation, maintaining electromagnetic wave absorbing and thermal conductivity properties over time, outperforming related art in both high-frequency and super-high-frequency applications.

Implementation Method 1

a high-specific-gravity soft magnetic filler having a specific gravity of 4.5 or greater

Methodology Applied
Scientific EffectElectromagnetic wave absorption: Absorption (EM radiation)

Implementation Method 2

suppresses transmission of not only noise including a high-frequency component (for example, with a frequency of 10 MHz to 10 GHz) but also noise including a super-high-frequency component (for example, with a frequency of 10 to 20 GHz)

Methodology Applied
Scientific EffectMagnetic loss: Magnetic Hysteresis

Implementation Method 3

an intermediate-specific-gravity thermally conductive filler having a specific gravity of 4.0 or less

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

improves heat dissipation, maintaining electromagnetic wave absorbing and thermal conductivity properties over time

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 5

a non-liquid anti-thickening and anti-settling agent... suppressing, in the silicone composition, settling of the high-specific-gravity soft magnetic filler and the intermediate-specific-gravity thermally conductive filler

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 6

maintaining uniform viscosity and composition

Methodology Applied
Scientific EffectViscosity stabilization: Viscoelasticity

Data Source

PatentEP3919557B1Silicone composition and curable grease
Publication Date: 2025.01.15 SEKISUI POLYMATECH CO LTD

AI summary

[Abstract] To provide a silicone composition in which, in an uncured state, settling of a high-specific-gravity soft magnetic filler is suppressed and which, therefore, has excellent extended storage stability and to provide a curable grease that can be obtained by curing the silicone composition. A silicone composition having an electromagnetic wave absorbing property and thermal conductivity includes liquid silicone; a high-specific-gravity soft magnetic filler having a specific gravity of 4.5 or greater; an intermediate-specific-gravity thermally conductive filler having a specific gravity of 4.0 or less; and a non-liquid anti-thickening and anti-settling agent. Furthermore, a curable grease is a two-component curable grease including a combination of a base compound and a curing agent that are used by being mixed together when used, the curable grease being to be cured by mixing of the base compound with the curing agent. The base compound is a silicone composition of the present invention, in which the liquid silicone is an organopolysiloxane having a vinyl group at an end thereof. The curing agent is a silicone composition of the present invention, in which the liquid silicone is an organohydrogenpolysiloxane.