One-Part TIM Composition With Heat-Activated Flow Stability
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Solution Overview
Problem
One-part dispensable thermal interface materials (TIMs) suffer from unstable flow rates over time, which affects their effectiveness in managing heat and electromagnetic interference (EMI) in electronic devices.
Innovation Solution
Incorporating a temperature-activatable thixotropic agent into the matrix of the composite, which activates upon heating to increase and stabilize the flow rate of the composite, enhancing its thermal conductivity and EMI mitigation capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-part dispensable thermal interface material is used to fill gaps between thermal transfer surfaces, then thermal transfer efficiency is improved compared to air gaps, but the flow rate of the material becomes unstable over time
Solution Approach 1:
The patent introduces a temperature-activatable thixotropic agent that changes the rheological parameters of the TIM. At storage and dispensing temperatures, the agent maintains a stable, higher viscosity for consistent flow rates. When activated by heat during operation, the viscosity decreases to optimize thermal transfer efficiency, thus resolving the contradiction between flow stability and thermal performance
Solution Approach 2:
The TIM incorporates a dynamic thixotropic property that allows the material to adapt its viscosity based on operational conditions. The temperature-activatable thixotropic agent enables the material to transition from a stable, viscous state during dispensing to a more fluid state during thermal operation, achieving both stable flow rates and effective heat transfer
2Ease of operation
If the flow rate of the thermal interface material is increased to improve dispensing performance, then ease of operation is improved, but the stability of the flow rate over time deteriorates
Solution Approach 1:
The temperature-activatable thixotropic agent enables the TIM to maintain different viscosity parameters at different temperatures. During dispensing at ambient temperature, the material exhibits stable, controllable flow characteristics. During operational heating, the viscosity parameter changes to optimize both dispensing performance history and current thermal interface functionality
3Reliability
If thermal interface materials with high thermal conductivity are used to improve heat removal, then heat transfer efficiency is improved, but the material complexity increases
Solution Approach 1:
The patent employs a composite TIM formulation containing a base polymer matrix, thermally conductive fillers (such as metal oxides or ceramic particles), and a temperature-activatable thixotropic agent. This composite structure achieves high thermal conductivity through the fillers while the integrated thixotropic mechanism provides flow control without requiring additional separate components or complex application equipment
Solution Approach 2:
The temperature-activatable thixotropic agent serves multiple functions: it provides flow stability during storage and dispensing, enables proper material distribution, and then transforms under heat to optimize thermal contact. This multi-functionality reduces the need for separate processing steps or additional materials, thereby reducing overall system complexity despite the enhanced thermal performance
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 composite maintains a stable flow rate of 90-125 grams per minute for at least 180 days, providing effective thermal management and EMI mitigation, with a thermal conductivity of at least 6 W/mK, suitable for various electronic device applications.
Implementation Method 1
a temperature-activatable thixotropic agent within the matrix, wherein the temperature-activatable thixotropic agent is activatable upon heating of the composite to a predetermined minimum temperature for at least a predetermined minimum amount of time, wherein activation of the temperature-activatable thixotropic agent increases flow rate and flow rate stability over time of the composite
Implementation Method 2
The heat sink may then be cooled by conventional convection and/or radiation techniques. During conduction, the heat may pass from the operating electrical component to the heat sink
Implementation Method 3
The heat sink may then be cooled by conventional convection and/or radiation techniques
Implementation Method 4
The heat sink may then be cooled by conventional convection and/or radiation techniques
Implementation Method 5
The thermal interface material may be used to fill the gap between thermal transfer surfaces, in order to increase thermal transfer efficiency as compared to having the gap filled with air, which is a relatively poor thermal conductor
Implementation Method 6
These shields are typically employed to localize EMI/RFI within its source, and to insulate other devices proximal to the EMI/RFI source. These shields may be composed of metal, polymer-inorganic composites
Implementation Method 7
These shields are typically employed to localize EMI/RFI within its source, and to insulate other devices proximal to the EMI/RFI source
Data Source
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AI summary
Disclosed are exemplary composites useful for the management of heat and/or electromagnetic interference (EMI), such as one-part dispensable thermal management and/or electromagnetic interference (EMI) mitigation materials, etc. In exemplary embodiments, a composite comprises a matrix, one or more fillers within the matrix, and a temperature-activatable thixotropic agent within the matrix. The temperature-activatable thixotropic agent is activatable upon heating of the composite to a predetermined minimum temperature for at least a predetermined minimum amount of time whereby activation of the temperature-activatable thixotropic agent increases flow rate and flow rate stability over time of the composite. Also disclosed are exemplary methods of enhancing flow rate characteristics of composites that are useful for management of heat and/or electromagnetic interference (EMI). In exemplary methods, a temperature-activatable thixotropic agent is used to increase flow rate and increase flow rate stability over time of the composite.