Hexagonal Boron Nitride Powder Agglomerate Structure Control
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Solution Overview
Problem
Conventional hexagonal boron nitride powders with agglomerates have high DBP absorption rates and low tap bulk density, leading to increased solvent requirements, reduced heat conductivity, and dielectric strength in heat-conductive insulating sheets due to void formation and poor resin filling properties.
Innovation Solution
A hexagonal boron nitride powder with hexagonal agglomerates having a specific surface area of 1.31 to 7.0 m2/g, a DBP absorption rate of 50 to 100 ml/100 g, and a tap bulk density of 0.66 to 0.95 g/cm3, produced by mixing an oxygen-containing boron compound, carbon source, and boron carbide, then reduction nitrided in a nitrogen atmosphere at 1,700 to 2,100°C, to achieve low maximum torque and high resin filling density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hexagonal boron nitride powder contains hexagonal boron nitride agglomerates, then heat conductivity is improved, but DBP absorption rate increases and tap bulk density decreases
Solution Approach 1:
The invention controls the DBP absorption rate within 50 to 100 ml/100g and tap bulk density within 0.66 to 0.95 g/cm³ by optimizing the agglomerate structure. This parameter control ensures that the powder has sufficient heat conductivity while limiting excessive solvent absorption and maintaining good flowability for resin filling.
2Temperature
If hexagonal boron nitride powder contains hexagonal boron nitride agglomerates, then heat conductivity is improved, but tap bulk density decreases
Solution Approach 1:
The invention optimizes the tap bulk density to be within 0.66 to 0.95 g/cm³ by controlling the agglomerate structure. This ensures that the powder maintains good flowability and filling properties while still providing the heat conductivity benefits of agglomerated particles.
3Quantity of substance
If the absorption amount increases, then the required amount of diluent solvent increases, but drying time increases and voids form
Solution Approach 1:
By controlling the DBP absorption rate within 50 to 100 ml/100g, the invention limits the amount of diluent solvent needed, which in turn reduces drying time and minimizes void formation in the final heat-conductive insulating sheet.
4Quantity of substance
If the content of single particles is high, then DBP absorption rate decreases, but viscosity increases and resin filling property deteriorates
Solution Approach 1:
The invention maintains an appropriate balance by controlling the DBP absorption rate within 50 to 100 ml/100g, which corresponds to an optimal single particle content. This ensures that the powder has good resin filling properties and appropriate viscosity while still providing sufficient heat conductivity.
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 powder reduces solvent usage, minimizes voids, enhances heat conductivity, and improves dielectric strength by ensuring dense agglomeration and high tap bulk density, facilitating efficient resin filling and heat path formation in heat-conductive insulating sheets.
Implementation Method 1
heating the mixture in a nitrogen atmosphere at 1,700 to 2,100°C to reduction nitride it
Data Source
AI summary
To provide a hexagonal boron nitride powder which contains agglomerates, has a maximum torque calculated by measuring in accordance with JIS-K-6217-4 of 0.20 to 0.50 Nm, a DBP absorption rate of 50 to 100 ml/100 g, a tap bulk density of 0.66 to 0.95 g/cm3 and reduced anisotropy of heat conduction and can provide high heat conductivity and dielectric strength to a resin composition produced by filling a resin therewith and a process for producing the powder by carrying out a reduction nitriding reaction using boron carbide.