Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Particulate matter
Reexamination Certificate
2000-02-17
2003-09-23
Bos, Steven (Department: 1754)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Particulate matter
C428S404000, C428S407000, C424S059000, C524S430000
Reexamination Certificate
active
06623858
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to metal oxide doped cerium oxides and a method for the preparation thereof. Further, the present invention relates to a resin composition or a cosmetic composition in which said metal oxide doped cerium oxides or a complex composed of said metal oxide solid doped cerium oxides and an oxide are blended.
2. Description of the Prior Art
As is well known, ultra violet ray causes degradation of plastic resins, and many kinds of countermeasure are carried out to protect the degradation. As one of the countermeasure method, it is widely practiced that a plastic resin is admixed with an ultraviolet shielding agent including an organic ultra violet ray absorbing agent or an inorganic ultraviolet ray scattering agent. And by admixing these agents in plastic resin, the adverse influence of ultra violet ray is reduced. As the organic ultra violet ray absorbing agent, salicylic acid type compound, benizophenon type compound, benzotriazol type compound or cyanoacrylate type compound can be mentioned, however, recently, the lack of heat resistance, lack of durability to weather or the safety of decomposed chemicals of it are becoming serious problems. To solve these problems, fine particles of titanium dioxide or fine particles of zinc oxide which are the inorganic ultra violet ray scattering agent are developed, however, the lack of dispersability of these agents is a problem and the catalytic activity of these agent are becoming a new problem. Recently, especially regarding titanium dioxide, it is pointed out that the generation of singlet oxygen by photo catalyst function of it causes new problem.
Ultraviolet ray has an adverse influence also on living bodies. Namely, it is well-known that the so called UV-B ultraviolet ray in the wavelength range of 280 to 320 nm causes cutaneous inflammations such as erythemas blister and the like while the so called UV-A ultraviolet ray in the wavelength range 320 to 400 nm causes tanning of skin by the accelerated formation of melanin. As the countermeasure method against above mentioned adverse influences of the ultraviolet ray, many kinds of sunscreen cosmetic compositions have been developed hereto before. The ultraviolet shielding agents contained in conventional sunscreen cosmetic compositions can be grossly classified into two types including an ultraviolet absorbing agent such as cinnamic acid type, benzophenon type or dibenzoylmethane type and an ultraviolet scattering agent such as zinc oxide or titanium dioxide. However, above mentioned ultraviolet absorbing agents have several problems, such as low absorptivity of ultraviolet ray and safety when the admixing amount in a cosmetic composition is too high. Further, in a case of conventional ultraviolet scattering agent, since it is impossible to improve the transparency even if the (dispersibility of particles is improved, the admixing use of it not only causes the deterioration of feeling when the cosmetic composition is applied but also the skin look becomes unnatural. Recently, the use of cerium compound as an ultraviolet scattering agent has been proposed, for example, in Japanese Patent Laid Open Publication 6-145645 or Japanese Patent Laid Open Publication 7-207151. However, since cerium oxide has strong catalytic activity, it has a problem that accelerates the oxidation decomposition of resin or oil and causes color change and generates offensive odor when admixed in cosmetic compound or resin. Thereupon, the development, of new cerium compound which has a function as the ultraviolet scattering agent and does not have catalytic activity has been desired. And in Japanese Patent Laid Open Publication 9-118610, silica-cerium oxide composite particle is proposed, however, the reduction of catalytic activity of said silica-cerium oxide composite particle is almost accomplished but the ability for ultraviolet ray shielding is not sufficient.
OBJECT OF THE INVENTION
The present invention is carried out concerning above mentioned circumstance, whose object is to provide metal oxide doped cerium oxides with strong ultraviolet ray shielding ability, lower catalytic activity and with excellent transparency. Further, the other object of this invention is to provide a composite composition of said metal oxide doped cerium oxides coated with metal oxide. Furthermore, the other object of this invention is to provide a resin composition or a cosmetic composition to which said metal oxide doped cerium oxides or a composite thereof is admixed with.
BRIEF SUMMARY OF THE INVENTION
That is, the present invention is the metal oxide doped cerium oxides composed of cerium oxide in which metal ion having larger ion radius than that of tetravalent cerium ion (Ce
4+
) and/or lower valence metal ion than Ce
4+
are doped. As the concrete example of a metal ion used in this doping, Ca
2+
, Y
3+
, La
3+
, Nd
3+
, Eu
3+
, Tb
3+
, Sm
3+
, Mg
2+
, Sr
2+
, Ba
2+
, Ce
3+
and the like can be mentioned. The desirable cerium oxide concentration in said metal oxide solid doped cerium oxide is 40 to 98 molar %. Further, when the color index of said metal oxide doped cerium oxide is estimated by L*, a* and b* space, the desirable region of L* is larger than 80, the desirable region of a* is smaller than 4 by absolute value and desirable region of b* is smaller than 10 by absolute value, further the desirable average particle size is ultra fine particle of 2 to 4 nm.
Further the metal oxide doped cerium oxides of this invention can be prepared by following steps. That is, prepare the metal oxide doped cerium oxide 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 Ce
4+
and/or lower valence metal ion than Ce
4+
and alkali, then by adding oxidizing agent in it at the temperature lower than 60° C. Furthermore the metal oxide doped cerium oxide of this invention can be prepared by adding and mixing aqueous solution of cerium salt, aqueous solution of metal ion having larger ion radius than that of Ce
4+
and/or lower valence metal ion than Ce
4+
, alkali and oxidizing agent simultaneously at the temperature lower than 60° C. and in the condition of pH higher than 5.
The present invention also relates to a composite composition of said metal oxide doped cerium oxides coated by one or more kinds of oxide selected from the group composed of silicon oxide, zirconium oxide, aluminium oxide, iron oxide and titanium dioxide. Further, the present invention relates to the resin composition to which said metal oxide doped cerium oxide or the composite composition thereof is blended. Still further, the present invention relates to the cosmetic composition to which said metal oxide doped cerium oxide or the composite composition thereof is blended. The surface treated metal oxide doped cerium oxides or the composite composition thereof can be blended to the cosmetic composition. And, said cosmetic composition can contain an ultraviolet ray absorbing agent, and/or an ultraviolet ray scattering agent. As the desirable example of said ultraviolet ray absorbing agent, one or more kinds of compound selected from the group composed of oxybenzone, octyl metoxycinnamate and 4tertbutyl-4′-methoxy dibenzoylmethane can be mentioned, and the desirable contents of the ultraviolet ray absorbing agent is 0.1 to 40% by weight. As the desirable example of said ultraviolet ray scattering agent, titanium dioxide and/or zinc oxide can be mentioned, and the desirable contents of the ultraviolet ray scattering agent is 0.1 to 50% by weight. Above mentioned cosmetic composition is suited to be used as a sunscreen cosmetic composition.
The metal oxide doped cerium oxide of this invention is the cerium oxide in which metal ion having larger ion radius than that of Ce
4+
and/or lower valence metal ion than Ce
4+
are doped. By doping said meta
Momose Shigeyoshi
Sato Tsugio
Tahira Kazuyuki
Tofukuji Kota
Yabe Sinryo
Bos Steven
Kose Corporation
Sherman & Shalloway
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