Mixed Boron Nitride Composition for Thermal Conductivity
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Solution Overview
Problem
Boron nitride compositions used as fillers in polymer-based materials exhibit poor rheological properties, making it difficult to dispense at loaded concentrations above 30 wt.%, and there is a need for improved thermal conductivity and large-scale applications such as electronic materials and thermally conductive compositions.
Innovation Solution
A boron nitride composition comprising a blend of at least two different types of boron nitride powder materials, including platelet and non-platelet forms, which are mixed and functionalized to enhance thermal conductivity and reduce viscosity, allowing for higher loading percentages without compromising dispenseability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If platelet BN is added as a filler to a polymer at loaded concentrations above 30 wt.%, then thermal conductivity is improved, but the blended material becomes so viscous that it is difficult to dispense from a mechanical dispenser
Solution Approach 1:
The patent applies segmentation by dividing the BN filler into two distinct size categories: fine particles (0.5-10 microns) and coarse particles (10-100 microns). This size segmentation allows the fine particles to act as spacers that prevent coarse particle aggregation, thereby reducing viscosity while maintaining thermal conductivity. The segmented approach resolves the contradiction by enabling high filler loading without excessive viscosity increase.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different particle sizes within the composite. Fine BN particles are positioned in the polymer matrix to provide thermal conduction pathways and act as spacers, while coarse BN particles provide bulk thermal conductivity. This local differentiation of particle functions allows the composite to achieve both high thermal conductivity and acceptable dispensability.
2Temperature
If higher concentrations of BN are used in polymer composites, then thermal conductivity is enhanced, but the material becomes too viscous to process
Solution Approach 1:
The patent segments the BN filler into fine and coarse particle fractions, where fine particles (0.5-10 microns) serve as spacers that prevent coarse particle aggregation. This segmentation enables higher overall BN concentration (above 30 wt.%) to be achieved without causing excessive viscosity increase that would hinder processing. The fine particles fill interstitial spaces and maintain fluidity even at high filler loadings.
Solution Approach 2:
The patent creates a composite filler system combining two different BN particle sizes rather than using a single particle size. This composite filler approach leverages the complementary properties of fine and coarse particles: fine particles improve flow and prevent aggregation, while coarse particles provide high thermal conductivity. The resulting composite filler system enables both high thermal conductivity and processability.
3Ease of operation
If spherical BN agglomerates are used to reduce viscosity, then dispensability is improved, but thermal conductivity may be compromised due to agglomerate structure
Solution Approach 1:
The patent inverts the conventional approach by not using pre-formed spherical agglomerates, but rather creating a pseudo-agglomerate structure in situ through the interaction of fine and coarse particles. Instead of making coarse particles spherical to improve flow, the patent uses fine particles to induce a dispersed, fluid-like behavior in the coarse particle system. This inversion resolves the contradiction by achieving both low viscosity and high thermal conductivity through a different structural mechanism.
Data Source
AI summary
A boron nitride composition comprising at least two different boron nitride powder materials having different properties, e.g., surface areas, particle size, tap density, etc.