Method for Producing Hexagonal Boron Nitride, and Heat Dissipation Sheet

• US 20160333246A1
• Filed: 01/08/2015
• Published: 11/17/2016
• Est. Priority Date: 01/08/2014
• Status: Active Grant

• Current Assignee: Denka Company Limited, National University Corporation Yokohama National University
• Original Assignee: Denka Company Limited, National University Corporation Yokohama National University
• Inventors: Sotokawa, Midori, Tatami, Junichi, Ikarashi, Koki, Hirotsuru, Hideki
• Granted Patent: US 9,879,168 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C01B 21/064 with boron
• CPC Class Codes: C01B 21/0646 Preparation by pyrolysis of boron and nitrogen containing compounds
• CPC Class Codes: C01B 21/0648 After-treatment, e.g. grinding, purification transformation of hexagonal into cubic or wurtzitic boron nitride C04B35/5831
• CPC Class Codes: C01P 2002/70 defined by measured X-ray, neutron or electron diffraction data
• CPC Class Codes: C01P 2004/61 Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C01P 2006/32 Thermal properties
• CPC Class Codes: C08K 2003/385 Binary compounds of nitrogen with boron
• CPC Class Codes: C08K 2201/001 Conductive additives
• CPC Class Codes: C08K 3/38 Boron-containing compounds
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: C09D 5/32 Radiation-absorbing paints protection against X-, gamma- or corpuscular radiation G21F
• CPC Class Codes: C09K 5/14 Solid materials, e.g. powdery or granular

Abstract

There is provided a method for producing hexagonal boron nitride, including a heating step of heating a mixture containing boron carbide and an alkaline earth metal compound under an ammonia atmosphere at 1300-1500° C. to obtain a product containing hexagonal boron nitride, wherein a molar ratio of the boron carbide to the alkaline earth metal compound in the mixture is 0.5-2.0.

Claims

1. A method for producing hexagonal boron nitride, comprising a heating step of heating a mixture containing boron carbide and an alkaline earth metal compound under an ammonia atmosphere at 1300-1500°

C. to obtain a product containing hexagonal boron nitride, wherein a molar ratio of the boron carbide to the alkaline earth metal compound in the mixture is 0.5-2.0.

2. The method for producing hexagonal boron nitride according to claim 1, wherein the alkaline earth metal compound contains at least one selected from the group consisting of calcium carbonate, strontium carbonate, and barium carbonate.

3. The method for producing hexagonal boron nitride according to claim 1, further comprising a purification step of removing a solution containing a different compound from the hexagonal boron nitride from a suspension obtained by mixing the product and a washing liquid containing an acid to obtain a solid product containing the hexagonal boron nitride.

4. The method for producing hexagonal boron nitride according to claim 1, wherein a mean particle size of the hexagonal boron nitride is 0.1-300 μ

m, and a graphitization index (GI) of the hexagonal boron nitride is 6 or less.

5. A heat dissipation sheet comprising the hexagonal boron nitride obtained by the production method according to claim 1 and at least one of a resin and a rubber.