| abstract |
The present invention evaluates the hydrophobicity of powder. In the present invention, the powder is put into a mixed solvent composed of a lipophilic solvent and a hydrophilic solvent, the lipophilic solvent is added to the mixed solvent into which the powder is put, and the voltage ratio of the mixed solvent is measured at predetermined time intervals. R, a parameter x related to the powder concentration is defined for an arbitrary voltage ratio R, and a continuous function HP(x) for the lipophilic solvent ratio corresponding to this x is defined. Furthermore, HP(x) with respect to the x used is used as a representative value of the lipophilic solvent ratio distribution, and is used as an index of hydrophobicity. |