Resin Sheet Thermal Conductivity via Boron Nitride Particle Grading
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Solution Overview
Problem
The increasing demand for enhanced thermal conductivity in resin sheets due to higher circuit speeds and integration densities in electronic components is not adequately met by existing thermal conductive resin sheets, particularly those using boron nitride particles.
Innovation Solution
A method involving the mixing of blocky and scaly boron nitride particles with specific size and compressive strength ratios within a resin composition, followed by molding and pressurization to create a resin sheet with improved thermal conductivity, where the blocky particles form thermal conduction channels and the scaly particles fill interspaces, enhancing heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the filling rate of boron nitride particles is increased to enhance thermal conductivity, then thermal conductivity is improved, but the resin sheet becomes difficult to mold and pressurize uniformly
Solution Approach 1:
The patent applies local quality by using two distinct types of boron nitride particles with different properties: blocky particles (average diameter 30 μm or more, compressive strength ≥5 MPa) that maintain aggregation and provide thermal conduction channels, and scaly particles (average diameter 1-30 μm, compressive strength <5 MPa) that disperse to fill interspaces. This local differentiation of particle properties enables both high thermal conductivity and good moldability
Solution Approach 2:
The patent employs composite materials by combining two types of boron nitride particles with different morphologies and mechanical properties in a resin matrix. The blocky particles form aggregated structures for thermal conduction while the scaly particles fill gaps, creating a composite filler system that achieves superior thermal conductivity (≥10 W/m·K) while maintaining manufacturability
2Temperature
If only blocky boron nitride particles are used to form thermal conduction channels, then thermal conductivity is improved, but interspaces remain empty reducing overall thermal performance
Solution Approach 1:
The patent applies the nested doll principle by having scaly boron nitride particles fill the interspaces between blocky boron nitride particles. The smaller scaly particles nest into the gaps created by the larger blocky particles, maximizing the filling rate and eliminating voids that would otherwise reduce thermal performance. This nested arrangement ensures continuous thermal conduction paths throughout the resin sheet
3Strength
If scaly boron nitride particles with high compressive strength are used, then particle integrity is maintained, but they do not disperse to fill interspaces effectively
Solution Approach 1:
The patent applies parameter changes by controlling the compressive strength of scaly boron nitride particles to be less than 5 MPa, which is lower than the blocky particles (≥5 MPa). This parameter adjustment enables the scaly particles to disperse and fill interspaces effectively during molding while the blocky particles maintain their aggregation for thermal conduction. The differentiated compressive strength parameters optimize both dispersibility and structural integrity
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 resulting resin sheet exhibits superior thermal conductivity, effectively addressing the need for improved heat radiation in electronic components by increasing the filling rate of boron nitride and optimizing the compressive strength of the particles for enhanced thermal performance.
Implementation Method 1
blocky boron nitride particles A including scaly boron nitride primary particles a aggregated... the boron nitride primary particles a having a length in a shorter direction of 0.7 μm or less
Implementation Method 2
scaly boron nitride primary particles b that do not form blocky boron nitride particles, and are disposed in interspaces among the blocky boron nitride particles A
Data Source
AI summary
A method of producing a resin sheet, including: mixing blocky boron nitride particles A, blocky boron nitride particles B, and a resin composition, and molding the resin composition to a sheet form and pressurizing the sheet form resin composition, the boron nitride primary particles a having a length in a shorter direction of 0.7 μm or less, the boron nitride primary particles b having a length in a shorter direction of 1 μm or more, the blocky boron nitride particles A having an average particle diameter of 30 μm or more, the blocky boron nitride particles B having an average particle diameter that is smaller than the average particle diameter of the blocky boron nitride particles A, the compressive strengths ratio of the blocky boron nitride particles A to the blocky boron nitride particles B being 1.2 or more. Thus, the thermal conductivity of a resin sheet can be enhanced.