Abstract: The present invention relates to the metal oxide doped cerium oxide which has an excellent ultraviolet ray shielding effect and a transparency and whose catalytic activity is reduced. More in detail, relates to the metal oxide doped cerium oxide composed of cerium oxide in which metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+, such as Ca2+, Y3+, La3+, Nd3+, Eu3+, Tb3+, Sm3+, Mg2+, Sr2+, Ba2+, Ce3+ and so on are doped. Said metal oxide doped cerium oxide can be prepared at the temperature lower than 60 ° C. and in the condition of pH higher than 5 by reacting aqueous solution of cerium salt, aqueous solution of metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+ and alkali, then adding oxidizing agent. Further, said metal oxide doped cerium oxide can be blended to resin composition or cosmetic composition and can display and ultraviolet shielding effect without spoiling transparency at visible ray region.

Abstract: The present invention relates to the metal oxide doped cerium oxide which has an excellent ultraviolet ray shielding effect and a transparency and whose catalytic activity is reduced. More in detail, relates to the metal oxide doped cerium oxide composed of cerium oxide in which metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+, such as Ca2+, Y3+, La3+, Nd3+, Eu3+, Tb3+, Sm3+, Mg2+, Sr2+, Ba2+, Ce3+ and so on are doped. Said metal oxide doped cerium oxide can be prepared at the temperature lower than 60° C. and in the condition of pH higher than 5 by reacting aqueous solution of cerium salt, aqueous solution of metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+ and alkali, then adding oxidizing agent.

Abstract: A metal oxide doped cerium oxide has an excellent ultraviolet ray shielding effect and transparency and reduced catalytic activity. The doping mextal oxide is an oxide of a metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+, such as Ca2+, Y3+, La3+, Nd3+, Eu3+, Tb3+, Sm3+, Mg2+, Sr2+, Ba2+, Ce3+. The metal oxide doped cerium is prepared by reacting aqueous solution of cerium salt, aqueous solution of metal ion having larger ion radius than that of Ce4+ and/or lower valence metal ion than Ce4+ and alkali at a temperature lower than 60° C. and at pH higher than 5. An oxidizing agent may be present together with the alkali or added subsequently. Resin compositions or cosmetic compositions blended with the metal oxide doped cerium oxide have improved ultraviolet shielding effect without spoiling transparency in the visible ray region.

Abstract: Proposed is a powder of silica-cerium oxide composite particles useful as an ultraviolet shielding agent in a resin composition or as a sunscreening agent in a cosmetic composition. The cerium oxide-based composite particles consist of cerium oxide and 5 to 60% by weight of amorphous silica calculated as SiO.sub.2. The composite particles are prepared by the addition of sodium silicate and an inorganic acid to an aqueous slurry containing precipitates of cerium hydroxide so as to precipitate amorphous silica on the particles of cerium hydroxide followed by drying and calcination of the particles separated from the reaction mixture. Various formulations of cosmetic compositions compounded with the silica-cerium oxide composite particles are disclosed.