# US 11,078,080 B2 · Hexagonal boron nitride powder and method for producing the same, and composition and heat dissipation material using the same

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,078,080 B2
- Document ID: US11078080B2
- Status: Granted
- Kind: B2
- Application number: 16/647,756
- Filed: 2019-06-12
- Published: 2020-09-03
- Granted: 2021-08-03
- Earliest claimed: 2018-09-07
- Assignees: Showa Denko K.K.
- Applicants: Showa Denko K.K.
- Inventors: Boanerges Thendie; Masaru Fukasawa
- Web page: https://patentgrep.com/patent/US11078080B2

## CPC

- C01B 21/0648: {After-treatment, e.g. grinding, purification (transformation of hexagonal into cubic or wurtzitic boron nitride C04B35/5831)}
- C01B 35/146: {Compounds containing boron and nitrogen, e.g. borazoles (ammonium tetrafluoborates C01B35/063; ammonium borates C01B35/12)}
- C01B 21/064: with boron
- C08K 3/38: Boron-containing compounds
- C08L 101/12: characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity (liquid crystal materials or compositions C09K19/00)
- C01P 2002/74: by peak-intensities or a ratio thereof only
- C01P 2004/30: extending in three dimensions
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/12: Surface area
- C01P 2006/16: Pore diameter
- C01P 2006/32: Thermal properties
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A hexagonal BN powder including aggregates of primary particles of hexagonal BN containing boron and oxygen as impurity elements at a content of 1.00 to 30.00% and 0 to 1.00% by mass, respectively, which has a peak A in a predetermined particle diameter range and a 50% volume cumulative particle diameter D50 (d1) of 30.0 to 200.0 μl in a particle size distribution curve, and in which a ratio of a height (a1) of the peak A before treatment to a height (a2) of the peak A after treatment is 0.80 to 1.00 and a ratio of D50 (d1) before treatment to D50 (d2) after treatment is 0.80 to 1.00 when the hexagonal BN powder is ultrasonically treated under a predetermined condition for 1 minute. Also disclosed is a method for producing the hexagonal BN powder, a composition and a heat dissipation material.

## Claims

### Claim 1

A hexagonal boron nitride powder comprising an aggregate of primary particles of hexagonal boron nitride,
comprising boron as an impurity element at a content of 1.00 to 30.00% by mass and oxygen as an impurity element at a content of 0 to 1.00% by mass, and
having a peak in a particle diameter range of 10.0 μm or more and less than 100.0 μm and a 50% volume cumulative particle diameter D50 (d1) of 30.0 to 200.0 μm in a particle size distribution curve representing volume-based frequency distribution,
wherein the hexagonal nitride powder has a structure such that, when the hexagonal boron nitride powder is ultrasonically treated under the following condition 1 for 1 minute, a ratio of a height (a1) of the peak before the ultrasonic treatment to a height (a2) of the peak after treatment, a2/a1, being 0.80 to 1.00 and a ratio of a 50% volume cumulative particle diameter D50 (d1) before ultrasonic treatment to a 50% volume cumulative particle diameter D50 (d2) after the ultrasonic treatment, d2/d1, being 0.80 to 1.00,
[condition 1] a powder sample dispersion obtained by mixing 0.06 g of the hexagonal boron nitride powder, 0.005 g of a detergent (“Mama Lemon (registered trademark)”, manufactured by Lion Corporation) and 50 g of water (20° C.) is placed in a 50 mL glass beaker having a barrel inner diameter of 40 mm and a height of 60 mm, and an end of a tip of a vibrator of an ultrasonic generator is set at a height of 1 cm from a bottom surface of a central portion of the beaker, and ultrasonic treatment is performed at an output of 150 W and an oscillation frequency of 19.5 kHz, and
wherein the boron as an impurity element is a boron atom not bound to a nitrogen atom and which does not form a hexagonal boron nitride molecule.

### Claim 2 (depends on 1)

The hexagonal boron nitride powder according to claim 1, having a BET specific surface area of 0.1 m2/g or more and less than 5.0 m2/g, and the primary particles each having a smooth surface.

### Claim 3 (depends on 1)

The hexagonal boron nitride powder according to claim 1, having a crystallite diameter derived from a (002) plane of hexagonal boron nitride, as determined by powder X-ray diffraction measurement, of 250 Å or more and less than 375 Å.

### Claim 4 (depends on 1)

The hexagonal boron nitride powder according to claim 1, having a BET specific surface area of 0.1 m2/g or more and less than 5.0 m2/g.

### Claim 5 (depends on 1)

The hexagonal boron nitride powder according to claim 1, wherein the content of the boron as the impurity element is 5.00 to 28.00% by mass.

### Claim 6 (depends on 1)

The hexagonal boron nitride powder according to claim 1, wherein the content of the boron as the impurity element is 10.00 to 25.00% by mass.

### Claim 7 (depends on 1)

A composition comprising a base material comprising one or two or more selected from the group consisting of a resin and a rubber, and the hexagonal boron nitride powder according to claim 1.

### Claim 8 (depends on 7)

A heat dissipation material comprising the composition according to claim 7.

### Claim 9 (depends on 8)

The heat dissipation material according to claim 8, being a heat dissipation sheet.

### Claim 10 (depends on 9)

The heat dissipation material according to claim 9, wherein a ratio of a diffraction peak intensity (I(002)) of a (002) plane to a diffraction peak intensity (I(100)) of a (100) plane, I(002)/I(100), of primary particles of hexagonal boron nitride, as determined in a direction perpendicular to a thickness direction of the heat dissipation sheet by X-ray diffraction measurement, is 7.0 to 15.

### Claim 11 (depends on 1)

A method for producing the hexagonal boron nitride powder according to claim 1, comprising:
step 1 of preparing a mixed powder comprising a boron powder and one or two or more boron compounds selected from the group consisting of a boron oxoacid and boron oxide,
step 2 of calcining the mixed powder under a noble gas atmosphere at 1200° C. or more and less than 1800° C. to obtain a calcined powder,
step 3 of granulating the calcined powder to obtain a granulated powder having a particle diameter of 10 to 200 μm,
step 4 of melting the granulated powder under a noble gas atmosphere at 1800 to 2300° C. to obtain a molten powder, and
step 5 of firing the molten powder under a nitrogen gas atmosphere at 2000 to 2300° C. to obtain a hexagonal boron nitride powder.

### Claim 12 (depends on 11)

The method for producing the hexagonal boron nitride powder according to claim 11, wherein the calcined powder obtained in the step 2 comprises boron suboxide.

### Claim 13 (depends on 11)

The method for producing the hexagonal boron nitride powder according to claim 11, wherein in the step 3, at least any of boron oxide and hexagonal boron nitride is added to the calcined powder for granulation.