Hexagonal Boron Nitride Powder Surface Modification
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Solution Overview
Problem
Hexagonal boron nitride powders with scaly particles and low surface functional groups face challenges in achieving high affinity with resins, leading to low heat conductivity and dielectric strength in resin compositions, while surface modification methods like plasma treatment increase costs and reduce water resistance.
Innovation Solution
A hexagonal boron nitride powder production process involving a mixture of an oxygen-containing boron compound, a carbon source with specific sulfur concentration, and an oxygen-containing calcium compound, heated in a nitrogen atmosphere to create particles with a high density of NH2 groups at the particle ends, enhancing resin affinity and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hexagonal boron nitride powder with scaly particles is used as filler in resin composition, then high electric insulation is achieved, but heat conductivity becomes low due to thermal anisotropy and orientation of scaly particles in plane direction
Solution Approach 1:
The invention modifies the surface properties locally at the particle ends of hexagonal boron nitride particles, introducing functional groups specifically at these locations to enhance resin affinity without changing the bulk crystal structure and thermal conductivity characteristics
2Reliability
If surface modification treatments such as plasma treatment or introducing functional groups are applied to hexagonal boron nitride powder, then resin affinity is improved, but water resistance deteriorates due to increased reactivity with moisture in air
Solution Approach 1:
The invention changes the type of functional group introduced on the particle surface from hydroxyl groups (OH) which are hygroscopic to amino groups (NH2) which provide good resin affinity while maintaining water resistance, thus changing the chemical parameter of the surface functional groups
3Object-affected harmful factors
If hexagonal boron nitride powder with small amount of surface functional groups is used, then water resistance is maintained, but resin affinity becomes low leading to poor heat transmission at the interface
Solution Approach 1:
The invention performs preliminary surface modification during the particle formation process itself, introducing amino functional groups at the particle ends before the particles are used in resin compositions, thereby pre-establishing good resin affinity without subsequent treatments that would compromise water resistance
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 hexagonal boron nitride powder exhibits improved affinity for resins, high water resistance, and increased heat conductivity, along with enhanced dielectric strength in resin compositions, without the drawbacks of traditional surface modification methods.
Implementation Method 1
heating the mixture in a nitrogen atmosphere at 1,450 to 1,550°C for 4 hours or more and at 1,650 to 2,100°C for 2 hours or more to reduction nitride it
Implementation Method 2
when H2 is added at a rate of 20 mbar per hour to boron nitride produced from permanent gas flow BCl3 and NH3 through a chemical vapor reaction
Data Source
Figure 1~2
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Figure 5~6
AI summary
A hexagonal boron nitride powder whose maximum absorption peak within the range of 3,100 to 3,800 cm-1 of the diffuse reflectance fourier transform infrared spectrum is existent at 3,530 to 3,590 cm-1 and which is able to provide high heat conductivity, dielectric strength and coper foil peel strength to a resin composition obtained by filling the powder into a resin, and a process for producing the above boron nitride powder by mixing together an oxygen-containing boron compound, a carbon source having a sulfur concentration of 1,000 to 10,000 ppm and an oxygen-containing calcium compound in a specific ratio and reduction nitriding the mixture.