PROBLEM TO BE SOLVED: To provide an environmentally friendly, simple and inexpensive method for manufacturing a tabular boehmite-based and tabular alumina-based powder capable of controlling a particle diameter, an aspect ratio and a form, and to provide a tabular powder having hydrophobicity and cosmetics having excellent feeling of use that are blended with the tabular powder.SOLUTION: In the production of tabular boehmite having a polygonal plate surface, a mean particle diameter between 1 &mum and 30 &mum and an aspect ratio (mean primary particle diameter/average thickness) between 2 and 50, a water-soluble aluminum compound is dissolved in water so that the concentration thereof is in the range of from 0.05 mol/L to 0.2 mol/L, added with sodium hydrogencarbonate and sodium carbonate so that the mole ratio of an aluminum ion and a sodium ion is in between 1:2 and 1:10, and is subjected to hydrothermal reaction for 1-30 hours under the condition of from 180°C to 300°C.COPYRIGHT: (C)2012,JPO&INPIT【課題】環境に優しく、簡便で低コストな方法にて、粒子径の制御ができ、アスペクト比や形態の制御が可能な板状ベーマイト及び板状アルミナ系粉体の製造方法を提供し、併せて疎水性が付与された板状粉体を提供し、これら板状粉体を配合することによって、使用感の優れた化粧料を提供する。【解決手段】板面が多角形で、平均粒子径が1μm~30μmの範囲であり、アスペクト比(平均一次粒子径/平均厚み)が2~50の範囲にある板状ベーマイトを製造するに際して、0.05mol/Lから0.2mol/Lになるように水溶性アルミニウム化合物を水に溶解し、アルミニウムイオンとナトリウムイオンがモル比で1:2~1:10の範囲内に入るように炭酸水素ナトリウム及び炭酸ナトリウムを加え、180℃から300℃での温度条件下で1時間~30時間水熱反応を行う。【選択図】なし
