Anisotropic Thermally Conductive Sheet for Heat and Permittivity Control
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Solution Overview
Problem
Conventional thermally conductive sheets face limitations in enhancing thermal conductivity while maintaining flexibility and controlling relative permittivity, as increasing the filling ratio of inorganic fillers can lead to powder fall and reduced flexibility, and existing materials do not effectively manage anisotropic thermal conductivity and permittivity.
Innovation Solution
A thermally conductive sheet comprising a binder resin, a first scaly or fibrous thermally conductive filler, and a second non-scaly, non-fibrous filler, where the fillers are dispersed to create a sheet with different thermal conductivity and permittivity in the thickness and surface directions, achieved through a manufacturing process involving resin composition preparation, molding, and slicing to orient the fillers effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the filling ratio of inorganic filler is increased to improve thermal conductivity, then thermal conductivity is improved, but flexibility deteriorates and powder fall occurs
Solution Approach 1:
The patent uses a composite material system combining binder resin with inorganic fillers (scaly particles and/or fibrous particles) to achieve both high thermal conductivity and flexibility. The composite structure allows the binder resin to provide flexibility while the filler particles provide thermal conduction pathways, resolving the contradiction between thermal performance and mechanical flexibility.
Solution Approach 2:
The patent changes the physical parameters of the filler particles by specifying particular aspect ratios (length-to-width ratio) and size ranges. By controlling these parameters, the patent optimizes the balance between thermal conductivity (improved by higher filler content) and flexibility (maintained by appropriate particle morphology and size distribution), preventing powder fall while enhancing heat dissipation.
2Temperature
If scaly particles or fibrous fillers are oriented in the thickness direction to improve thermal conductivity, then thermal conductivity in the thickness direction is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating orientation-promoting structures or treatments during the molding process. The scaly particles and/or fibrous fillers are pre-oriented in the thickness direction during sheet formation through controlled molding conditions, ensuring thermal conductivity enhancement is achieved without requiring complex post-manufacturing orientation steps.
Solution Approach 2:
The patent controls the orientation of anisotropic filler particles by adjusting molding parameters such as pressing direction, temperature, and pressure during manufacturing. By changing these process parameters, the scaly particles and/or fibrous fillers naturally align in the thickness direction, achieving high thermal conductivity without significantly increasing manufacturing complexity.
3Adaptability or versatility
If relative permittivity is controlled for electromagnetic wave management, then electromagnetic wave control is improved, but thermal conductivity optimization becomes more difficult
Solution Approach 1:
The patent applies local quality by selecting inorganic filler materials with specific local properties that simultaneously satisfy both electromagnetic wave control requirements (appropriate relative permittivity) and thermal conductivity requirements. Different filler materials or combinations are chosen to provide the necessary dielectric characteristics in certain regions while maintaining thermal conduction pathways, allowing both functions to coexist in the same thermally conductive sheet.
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 solution enables a thermally conductive sheet with anisotropic thermal conductivity and permittivity, enhancing heat dissipation and electromagnetic wave control, suitable for applications in shielding and antennas, while maintaining flexibility and improving thermal conductivity in the thickness direction.
Implementation Method 1
a first thermally conductive filler comprising a scaly thermally conductive filler and/or a fibrous thermally conductive filler... thermal conductivity in the thickness direction of the thermally conductive sheet and relative permittivity and thermal conductivity in the surface direction of the thermally conductive sheet are different
Implementation Method 2
relative permittivity and thermal conductivity in the thickness direction of the thermally conductive sheet and relative permittivity and thermal conductivity in the surface direction of the thermally conductive sheet are different
Data Source
AI summary
A thermally conductive sheet having a binder resin, a first thermally conductive filler, and a second thermally conductive filler, wherein the first thermally conductive filler and the second thermally conductive filler are dispersed in the binder resin, and the specific permittivity and the thermal conductivity are different in the thickness direction B and the surface direction A of the thermally conductive sheet. A thermally conductive sheet includes step A of preparing a resin composition for forming a thermally conductive sheet by dispersing a first thermally conductive filler and a second thermally conductive filler in a binder resin, step B of forming a molded block from the resin composition for forming a thermally conductive sheet, and step C of slicing the molded block into a sheet and obtaining a thermally conductive sheet having different relative permittivity and thermal conductivity in the thickness direction and the surface direction.