Thermally Conductive Polysiloxane Composition for Flexible Thermal Interface Materials
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Solution Overview
Problem
Existing thermally conductive polysiloxane compositions with organohydrogenesiloxanes having Si—H groups in side chains and terminals fail to provide satisfactory flexibility and tackiness.
Innovation Solution
A thermally conductive polysiloxane composition comprising a thermally conductive filler, a siloxane compound with an alkoxysilyl group and linear siloxane structure, a polyorganosiloxane with alkenyl groups, a linear polyorganohydrogensiloxane, and a platinum catalyst, with specific ratios and molecular structures to enhance tackiness and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If organohydrogenesiloxane having Si—H group in side chain and terminal is used, then thermal conductivity is improved, but flexibility and tackiness deteriorate
Solution Approach 1:
The patent changes the molecular structure parameters of the polyorganohydrogensiloxane from conventional side-chain Si—H groups to terminal Si—H groups with controlled distribution. Specifically, it uses a linear polyorganohydrogensiloxane with Si—H groups at terminals (Formula 4) combined with a polyorganohydrogensiloxane having at least three Si—H units per molecule (Formula 5), optimizing the ratio of terminal to internal Si—H groups to achieve both high thermal conductivity and excellent flexibility/tackiness
Solution Approach 2:
The patent creates a composite curing system by combining two types of polyorganohydrogensiloxanes with different molecular architectures: a linear type providing flexibility and a branched/multifunctional type providing crosslinking density. This composite approach allows the cured product to simultaneously achieve high thermal conductivity from the filler network and excellent mechanical properties from the optimized siloxane matrix structure
2Temperature
If high filling ratio of thermally conductive filler is achieved, then thermal conductivity is improved, but flexibility deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and structural parameters of the polyorganohydrogensiloxane components to achieve optimal viscosity and crosslinking density. By controlling the ratio of terminal to internal Si—H groups and adjusting the molecular weight distribution, the patent creates a matrix that can accommodate high filler loading while maintaining chain mobility and flexibility in the cured product
Solution Approach 2:
The polyorganohydrogensiloxane acts as an intermediary between the thermally conductive filler particles and the polyorganosiloxane base resin. The Si—H groups provide crosslinking sites that bond to the alkenyl groups on the filler surface and the base resin, creating a unified network that maintains flexibility even at high filler concentrations by distributing stress throughout the composite structure
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 a cured product with excellent tackiness and flexibility, suppressing peeling and allowing for easy reapplication, while maintaining thermal conductivity.
Implementation Method 1
a platinum catalyst
Implementation Method 2
an addition reaction curable thermally conductive polysiloxane composition
Data Source
AI summary
The present invention relates to a thermally conductive polysiloxane composition that provides a cured product having excellent tackiness and flexibility in which the composition contains (A) a thermally conductive filler, (B) a siloxane compound having an alkoxysilyl group and a linear siloxane structure, (C) a polyorganosiloxane having at least two alkenyl groups bonded to silicon atoms per molecule, (D1) a linear polyorganohydrogensiloxane represented by the general formula (4), (D2) a polyorganohydrogensiloxane having per molecule at least three units represented by the general formula (5), and (E) a platinum catalyst.