Drug – bio-affecting and body treating compositions – Topical sun or radiation screening – or tanning preparations
Patent
1997-12-11
1999-11-02
Dodson, Shelley A.
Drug, bio-affecting and body treating compositions
Topical sun or radiation screening, or tanning preparations
106461, 106471, 423554, 424 60, 424 69, 424400, 424401, A61K 742, A61K 700, C09C 102, C01F 1146
Patent
active
059765119
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an ultraviolet rays-absorbing composition and a process for producing the same. The ultraviolet rays-absorbing composition according to the present invention has a pearly luster and is very useful as a component of make-up cosmetics, coatings and the like.
BACKGROUND ART
Ultraviolet rays included in sunlight reaching the ground adversely affect the human body such as the skin, buildings such as houses, and the like so that various countermeasures for shielding ultraviolet rays have been proposed. While ultraviolet rays are divided into A region (wavelength of 320 to 380 nm) and B region (wavelength of 290 to 320 nm) according to Commission Internationale de l'Eclairage (CIE), it is of great concern that the amount of ultraviolet rays reaching the ground have recently been increasing with the decomposition of the ozonosphere by flon and the like. Furthermore, while the conventional target of shielding ultraviolet rays has been confined to B region, it has recently been revealed that the ultraviolet rays of A region penetrates deep into the skin to damage the tissue and accelerate skin aging. Therefore, not only B region but also A region have been attracting attention as a target of shielding ultraviolet rays.
Ultraviolet rays-absorbing compositions conventionally used in cosmetic sunscreens, ultraviolet rays-shielding coatings and the like mainly comprise organic compounds, such as benzophenone compounds, benzoic acid derivatives or the like. Since these organic compounds show absorption bands generally in the range of from 280 to 350 nm, the ultraviolet rays of A region cannot be completely shielded.
Additionally ultraviolet rays-absorbing compositions comprising organic compounds are problematical from the standpoint of safety to the human body.
Inorganic pigments showing broader ultraviolet rays-absorption bands have also been used in place of the organic compounds. In particular, a cosmetic composition or a coating composition containing ultrafine particles having an average primary particle size of 0.1 .mu.m or less forms a translucent coating film with a natural tone. Of these inorganic pigments, titanium oxide has enjoyed the most frequent use because it completely shields ultraviolet rays having a wavelength of 360 nm or shorter.
In recent years, zinc oxide has attracted attention as disclosed in JP-B-7-23294. Zinc oxide exhibits a still broader ultraviolet rays-absorption band than titanium oxide and completely shields ultraviolet rays having a wavelength of 370 nm or shorter. Furthermore, the hiding power of zinc oxide is not so high because of its low refractive index ranging from 1.9 to 2.0, so that it gives excellent translucence free from white turbidity when made into ultrafine particles of 0.1 .mu.m or smaller. For use in a coating composition, it can easily be colored. For use in cosmetics, zinc oxide can provide the composition with astringency or an antiinflammatory effect and also has a sebum absorbing effect.
Cerium oxide is known to have an ultraviolet rays-absorbing effect similarly to zinc oxide and titanium oxide. Although cerium oxide does not show a clear absorption end unlike zinc oxide or titanium oxide, it has a still broader absorption band than zinc oxide and titanium oxide and shields ultraviolet rays of 380 nm or shorter. Accordingly, cerium oxide can be used for its ultraviolet rays-absorbing effect similarly to zinc oxide and titanium oxide.
If ultrafine particles of zinc oxide, cerium oxide or titanium oxide are used as a component of cosmetics or coatings, they must be uniformly dispersed in a medium. However, ultrafine particles having a particle size, e.g., of 0.1 .mu.m or smaller readily undergo secondary agglomeration due to their great van der Waals forces. It is difficult to uniformly disperse the coarse secondary particles. Cosmetics, for instance, containing the particles in a non-uniformly dispersed state cannot get rid of color unevenness or an uncomfortable feel to the touch when applied to the skin.
In th
REFERENCES:
patent: 5171572 (1992-12-01), Suganuma et al.
patent: 5262148 (1993-11-01), Sugasawa et al.
Database WPI, Week 8311, Derwent Publications Ltd., London, GB; AN 83-26601k, XP002066138; and JP 58 021 455 A (Kubo Y.), Feb. 8, 1983 (abstract).
Database WPI, Week 9242, Derwent Publication Ltd., London, GB, AN 92-345112, XP002066139; and JP 04 249 584 A (Tayca Corp.) Sep. 4, 1992 (abstract).
Patent Abstracts of Japan, vol. 13, No. 487, (C-649), Nov. 6, 1989; and JP 01 190626A (Catalysts & Chem. Ind. Co.), Jul. 31, 1989 (abstract).
Ohtsu Koichi
Sato Noriaki
Dodson Shelley A.
Sakai Chemical Industry Co. Ltd.
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