MELAMINE BORATE PARTICLE, ITS PRODUCTION AND USE THEREOF AND PRODUCTION OF HEXAGONAL BORON NITRIDE POWDER

摘要

PROBLEM TO BE SOLVED: To produce a resin or a rubber product or a hexagonal boron nitride sintered compact having low anisotropy without deteriorating excellent characteristics of the hexagonal boron nitride. SOLUTION: A melamine borate particle comprising aggregated primary particles of needlelike crystals of melamine borate or a mixture containing the grains is produced. A crystallizing catalyst is then added thereto and the resultant mixture is heat-treated to produce a, hexagonal boron nitride powder, comprising a mixture of 20-100wt.% hexagonal boron nitride particles containing aggregated scaly primary particles of the hexagonal boron nitride without orienting with 80-0wt.% boron nitride particles other than the primary particles and having 1.0-2.5 graphitization index(GI) measured by a powder X-ray diffractometry at 6-20 ratio (I002 /I100 ) of the intensity I002 of a (002) diffraction line to the intensity I100 of a (100) diffraction line. The resultant powder is blended as a filler for a resin and/or a rubber therewith and formed or sintered to afford a sintered compact.