Thermally Conductive Silicone Elastomer With Low-Density Silicon Filler

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Solution Overview

Problem

Existing thermally conductive silicone elastomers used in automotive applications, such as electric vehicles, face challenges in achieving thermal conductivities above 2.0 W/m·K while maintaining low density and good processing properties, often resulting in powdery compositions if filler selection is inadequate.

Innovation Solution

A novel organopolysiloxane composition comprising at least 40% metallic silicon filler with specific particle size distribution and a two-component system for mixing, including a hydrosilylation catalyst, to achieve high thermal conductivity and low density, characterized by a particle size distribution ratio d90/d10 ≥ 20 and a two-part system for stable composition formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If metal oxide powders (ATH, aluminum oxide, magnesium oxide) are added at very high concentration to enhance thermal conductivity, then thermal conductivity is improved, but density increases

Engineering Contradiction:
Improvethermal conductivityVSAvoiddensity
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The invention changes the key parameter from using metal oxide powders to using metallic silicon powder with specific particle size distribution (d90/d10 ≥ 20 and 3-22% of particles ≤ 2 μm). This parameter change enables achieving thermal conductivity >2.0 W/m·K while maintaining density <3 g/cm³, resolving the contradiction between thermal conductivity enhancement and density control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system combining metallic silicon powder with specific particle size distribution and silicone elastomer matrix. This composite approach allows optimizing both thermal conductivity and density by leveraging the high thermal conductivity of metallic silicon while controlling overall density through particle size distribution and filler concentration (70-95 wt%)

Inventive Principle:
Principle #40Composite materials

2Temperature

If filler concentration is increased to achieve high thermal conductivity, then thermal conductivity is improved, but the composition becomes powdery and processing becomes impossible

Engineering Contradiction:
Improvethermal conductivityVSAvoidprocessing properties
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention changes the particle size distribution parameters of the filler (d90/d10 ≥ 20 ratio and 3-22% of particles ≤ 2 μm), which fundamentally alters the rheological properties of the composition. This enables maintaining good processing properties (non-powdery consistency) even at high filler concentrations (70-95 wt%), resolving the contradiction between achieving high thermal conductivity and maintaining manufacturability

Inventive Principle:
Principle #35Parameter changes

3Temperature

If conventional fillers are used to achieve thermal conductivity above 2.0 W/m·K, then thermal conductivity is improved, but density exceeds acceptable limits for automotive applications

Engineering Contradiction:
Improvethermal conductivityVSAvoiddensity
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The invention changes from conventional metal oxide fillers to metallic silicon powder with optimized particle size distribution. This material substitution combined with specific particle size parameters (d90/d10 ≥ 20) enables achieving thermal conductivity >2.0 W/m·K while keeping density <3 g/cm³, directly resolving the contradiction between thermal conductivity enhancement and density control for automotive applications

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 composition achieves thermal conductivities exceeding 2.0 W/m·K with a density below 3 g/cm³, ensuring stable processing and suitability for automotive applications.

Implementation Method 1

thermally conductive filler D, wherein said thermally conductive filler D comprises at least 40% by weight of metallic silicon

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a catalytically effective amount of at least one hydrosilylation catalyst C

Methodology Applied
Scientific EffectHydrosilylation: Chemical Bonding

Data Source

PatentUS12466952B2Thermally conductive silicone compositions
Publication Date: 2025.11.11 ELKEM SILICONES FRANCE SAS

AI summary

The present invention relates to organopolysiloxane compositions comprising an organopolysiloxane having, per molecule, at least two alkenyl groups, an organopolysiloxane having, per molecule, at least two SiH units, a hydrosilylation catalyst, and a thermally conductive filler, the thermally conductive filler comprising at least 40% by weigh of metallic silicon, and a specific particle size distribution. The invention further relates to a silicone elastomer which can be obtained by cross-linking and/or curing the composition, as well as its use as a thermally conductive material for coating or filling, in particular for the automotive field, in particular for the field of electric vehicles.