Two-Part Silicone Thermal Interface Composition With Low Oil Bleeding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional silicone compositions face challenges in increasing thermal conductivity while maintaining flexibility, long-term reliability, and preventing oil bleeding, especially when the filling rate of thermally conductive fillers is increased.
Innovation Solution
A two-part curing type silicone composition is developed, keeping the Si-H to alkenyl group ratio constant, using a specific organohydrogenpolysiloxane, and ensuring a viscosity difference of 400 mPa·s or less between components, to achieve improved flexibility, long-term reliability, and reduced oil bleeding while enhancing thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling rate of thermally conductive filler is increased, then thermal conductivity is improved, but viscosity increases and flowability decreases
Solution Approach 1:
The patent introduces a silane-modified polysiloxane as an intermediary substance that modifies the surface of thermally conductive fillers. This intermediary layer improves the dispersion of filler particles in the silicone resin, allowing higher filling rates without excessive viscosity increase. The silane modification creates a compatibility bridge between the inorganic filler and organic silicone matrix, reducing aggregation and maintaining flowability.
Solution Approach 2:
The patent changes the chemical parameters of the silicone resin by introducing silane-modified polysiloxane with specific molecular weight and crosslinking density. This parameter change allows the system to accommodate higher filler content while controlling viscosity through the modified polymer structure and its interaction with filler surfaces.
2Reliability
If the filling rate of thermally conductive filler is increased, then thermal conductivity is improved, but hardness increases and stress on electronic components increases
Solution Approach 1:
The silane-modified polysiloxane acts as a stress-distributing intermediary between the rigid thermally conductive filler particles and the surrounding electronic components. This intermediary layer prevents stress concentration at the filler-component interfaces, reducing the overall stress transmitted to electronic components while maintaining high filler content for thermal conductivity.
Solution Approach 2:
The patent creates a composite material system where silane-modified polysiloxane forms a flexible matrix that binds rigid thermally conductive filler particles. This composite structure combines the high thermal conductivity of the filler with the flexibility and stress-absorbing properties of the modified polymer matrix, achieving high thermal conductivity without excessive hardness.
3Reliability
If the filling rate of thermally conductive filler is increased, then thermal conductivity is improved, but long-term reliability deteriorates due to hardness increase
Solution Approach 1:
The silane-modified polysiloxane serves as a protective intermediary that prevents direct contact and stress concentration between rigid filler particles and electronic components during long-term use. This intermediary layer absorbs thermal expansion stresses and mechanical vibrations, preventing detachment and maintaining reliable thermal contact over time.
Solution Approach 2:
The silane modification creates a pre-formed cushioning layer on the filler particle surfaces before assembly. This beforehand cushioning prevents direct hard contact between filler particles and components, absorbing future thermal and mechanical stresses that would otherwise cause detachment and reliability deterioration during long-term operation.
4Ease of operation
If alkenyl group-containing organopolysiloxane is added to the second agent, then mass ratio equalization is achieved, but oil bleeding occurs during storage
Solution Approach 1:
The silane-modified polysiloxane acts as a compatibilizing intermediary between the organopolysiloxane and organohydrogenpolysiloxane components. This intermediary substance improves mutual solubility and prevents phase separation, eliminating oil bleeding while allowing the inclusion of alkenyl group-containing organopolysiloxane for mass ratio equalization in the two-part system.
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 achieves improved thermal conductivity, flexibility, and long-term reliability, with reduced oil bleeding and stress on electronic components, effectively addressing the limitations of conventional compositions.
Implementation Method 1
an organohydrogenpolysiloxane and an organopolysiloxane, wherein a difference in viscosity at 23° C. between the organohydrogenpolysiloxane and the organopolysiloxane is 400 mPa·s or less
Implementation Method 2
a thermally conductive filler... to dissipate the heat generated from the electronic components to the outside of the device
Data Source
AI summary
A silicone composition comprising: (a) a specific organopolysiloxane; (b) an organohydrogenpolysiloxane having Si-H at both two molecular chain ends and molecular-chain side chains, the number of Si-H in the molecular-chain side chains being 4 to 15; (c) a thermally conductive filler; and (d) a curing catalyst; the silicone composition comprising: a first agent comprising the components (a), (c) and (d) and not comprising the component (b) in combination with a second agent comprising the components (a), (b) and (c) and not comprising the component (d); a difference in viscosity at 23°C between the components (a) and (b) in the second agent is 400 mPa·s or less; and a ratio (H/Vi) of the number of Si-H to the number of alkenyl groups is in the range of 0.5 or more and 1.5 or less.