Method for analyzing degree of hydrophobization of powder, coloring pigment treated with high degree of hydrophobization, and cosmetic containing same

The invention evaluates the hydrophobicity of the powder. In the present invention, a powder is introduced into a mixed solvent comprising a lipophilic solvent and a hydrophilic solvent, the lipophilic solvent is added to the mixed solvent into which the powder is introduced, the voltage rates R of the mixed solvent are measured at predetermined time intervals, and a parameter x related to the concentration of the powder is defined for any voltage rate R. A continuous function HP (x) for the lipophilic solvent ratio corresponding to x is defined. Furthermore, HP (x) for the used x is used as a representative value of the ratio distribution of the lipophilic solvent, and is used as a hydrophobic index. 本发明评价粉体的疏水性。本发明中，将粉体投入由亲油性溶剂和亲水性溶剂组成的混合溶剂中，在投入了粉体的混合溶剂中添加亲油性溶剂，同时每隔规定时间间隔就测定混合溶剂的电压率R，对于任意的电压率R定义与粉体浓度相关的参数x，定义对于与该x对应的亲油性溶剂比率的连续函数HP(x)。而且，将对于所用的x的HP(x)作为亲油性溶剂比率分布的代表值，设为疏水性的指标。