| abstract |
A urea-containing external preparation for skin having a high moisturizing effect and in which precipitation of urea crystals is suppressed not only during storage but also after application to the skin. [Solution] Urea (X), An alkylene oxide derivative (Y) represented by the following general formula (I): A urea-containing external preparation for skin containing water (Z) and having a blending mass ratio of the above three components within a range surrounded by the following coordinates in a three-phase diagram. (X, Y, Z) = (50, 0.1, 49.9), (33, 67, 0), (30, 70, 0), (7, 70, 23), (7, 0.1, 92.9) (Chemical formula 1) R 1 O - [(AO) m (EO) n] -R 2 (I) (In the formula, AO is an oxyalkylene group having 3 to 4 carbon atoms, EO is an oxyethylene group, m and n are average added moles of AO and EO, respectively, and 1 ≦ m ≦ 70 and 1 ≦ n ≦ 70. The ratio of EO to the total of AO and EO is 20 to 80% by mass, AO and EO may be added in blocks or randomly, and R 1 and R 2 may be the same or (It is a C 1-4 hydrocarbon group or hydrogen atom that may be different, and the ratio of the number of hydrogen atoms to the number of hydrocarbon groups of R 1 and R 2 is 0.15 or less.) [Selection] Figure 1 |