PURPOSE: To provide an aqueous slurry having a low viscosity by dispersing the powder of boron nitride in water in the presence of a polyoxyethylene-based nonionic surfactant.
CONSTITUTION: An ether type surfactant of formula: XO(CH2CH2O)nH (X is an oleophilic group such as alkyl or aryl) such as polyoxyethylene dodecyl ether and having a HLB (represented by an equation: HLB = E/5) of ≥9 is suitably used as a polyoxyethylene-based nonionic surfactant. 100 pts.wt. of boron nitride powder having an average particle diameter of 0.01-100μm and a specific surface area of 1-200m2/g, 0.1-30 pts.wt. of the polyoxyethylene-based nonionic surfactant, a proper amount of water, and, if necessary, another dispersing agent, a binder, and a defoaming agent are mixed with each other by the use of a ball mill, etc., to provide an aqueous slurry of boron nitride having a low viscosity of ≤1000cps at 25°C.
MIYAGAWA TOMOHIRO
SHINDO TOSHIHIKO
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