Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1996-09-06
2002-08-27
Venkat, Jyothsna (Department: 1627)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S070110, C424S070120, C424S070121, C424S070122
Reexamination Certificate
active
06440429
ABSTRACT:
BACKGROUND OF THE INVENTION
a) Field of the Invention
This invention relates to an emulsified, water-in-oil type composition, which can give refreshed feeling of use without stickiness and is excellent in emulsion stability, and also to a skin cosmetic preparation containing same.
b) Description of the Related Art
As oil components usable in emulsified, water-in-oil compositions, many hydrocarbon oils such as liquid paraffin and squalane are known to date. When they are applied to skin cosmetic preparations, they cover the skin surface with an oil film and prevent evaporation of moisture so that they are effective for skin roughness and the like. Facial cosmetic preparations making use of these oil components have high treatment effects, while makeup cosmetic preparations with such oil components employed therein have excellent water repellency and feature long-lasting makeups.
On the other hand, emulsified, water-in-oil type cosmetic preparations added with silicone oils as oil components can give smooth feeling of use and are excellent in water repellency. In particular, cosmetic preparations added with volatile silicones feature good spreadability upon application and, as they are spread, the volatile silicone oils are allowed to evaporate, resulting in a reduction in the oils remaining on the skin surfaces. These cosmetic preparations therefore feature good adhesion, high durability against sebum and sweat, and long-lasting makeups. Further, combined use of a lower alcohol such as ethanol makes it possible to give pleasant refreshness and refreshed feeling of use because of the heat of vaporization taken away for their high volatility.
However, the addition of a lower alcohol such as ethanol makes it very difficult to obtain a stable water-in-oil emulsion system. An emulsified, water-in-oil cosmetic preparation which contains such a lower alcohol at a high concentration and has excellent stability has not been obtained despite the existence of a strong desire therefor. Conventionally known methods for obtaining emulsified, water-in-oil type cosmetic preparations having good stability include inter alia a method in which the content of a wax is increased to achieve solidification, a method making use of silica, and methods in which stable emulsification is conducted using a clay mineral and a polyoxy-alkylene-modified silicone [Japanese Patent Application Laid-Open (Kokai) No. SHO 61-218509, Japanese Patent Application Laid-Open (Kokai) No. SHO 64-63031, and Japanese Patent Application Laid-Open (Kokai) No. HEI 1-180237]. When a lower alcohol such as ethanol is added to provide refreshed feeling, however, these methods are still unable to provide stable emulsion products and are hence accompanied by a problem in the storage stability of emulsion products. Furthermore, concurrent use of a silicon e oil and ethanol or the like leads to a significant reduction in emulsion stability, so that the problem of separation becomes more dominant. Therefore, those added with ethanol or the like are generally accompanied by the irksome problem that users must shake them before use.
SUMMARY OF THE INVENTION
An object of the present invention is therefore to provide an emulsified, water-in-oil composition, which can give refreshed feeling of use, does not become sticky with time, and is excellent in emulsion stability, and also a skin cosmetic preparation containing the emulsified, water-in-oil composition, and also a skin cosmetic preparation containing the emulsified, water-in-oil composition.
Under the above-described current circumstances, the present inventors have carried out an extensive investigation. As a result, it has been found that use of a high polymer compound having orientation to oil-water interfaces, for example, one or more high molecular compounds—which are selected from copolymers capable of forming intra- and intermolecular crosslinks through bonds other than covalent bonds, copolymers containing hydrophilic segments soluble or dispersible in water or a lower alcohol and copolymers containing hydrophilic segments and an organopolysiloxane segment—as an emulsifier or emulsification aid can provide a cosmetic preparation which is excellent in emulsion stability even if a lower alcohol such as ethanol is included and, when applied to a skin cosmetic preparation, which gives refreshed feeling of use and remains stick-free even if time goes on, leading to the completion of the present invention.
Namely, the present invention provides an emulsified, water-in-oil type composition comprising the following components (A), (B), (C) and (D):
(A) an oil phase,
(B) a high molecular compound having orientation to oil-water interfaces,
(C) a lower alcohol, and
(D) water; and
a skin cosmetic preparation containing same.
The emulsified, water-in-oil type composition and skin cosmetic preparation containing same, both pertaining to the present invention, exhibit excellent emulsion stability, gives excellent refreshed feeling and is stick-free.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
No particular limitation is imposed on the oil phase as the component (A) insofar as it is an oil component commonly employed in cosmetic preparations. Illustrative of the component (A) are solid or semisolid oils such as vaseline, lanolin, ceresin, microcrystalline wax, carnauba wax, candelilla wax, cholesterol esters, high fatty acids, and higher alcohols; liquid oils such as jojoba oil, castor oil, isopropyl myristate, octyldodecyl myristate, trimethylolpropane triisostearate, diisostearyl malate, isostearyl alcohol, oleyl alcohol, oleic acid, isostearic acid, myristic acid, stearic acid, squalane, liquid paraffin, ester oils, triglycerides, diglycerides, and perfluoropolyethers; and silicone oils such as dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenylpolysiloxane, methylhydrogenpolysiloxane, higher-fatty-acid-modified organopolysiloxanes, higher-alcohol-modified organopolysiloxanes, and trimethyl siloxysilicate. These oil components can be used either singly or in combination.
The component (A) preferably contains one or more silicone oils. Preferred exemplary silicone oils include volatile dimethylpolysiloxane and dimethylcyclopolysiloxane having structures of the following formula (13), respectively.
The proportion of the silicone oil is preferably 5 to 100 wt. % based on the oil as the component (A). The proportion of the whole oil including the silicone oil is preferably 10-90 wt. % based on the emulsified, water-in-oil type composition, with 10-85 wt. % being more preferably and 15-85 wt. % being particularly preferred.
No particular limitation is imposed on the high molecular compound as the component (B), which has orientation to oil-water interfaces. The high molecular compound is preferably a viscous liquid or solid copolymer which forms intra-molecular crosslinks and inter-molecular crosslinks through bonds other than covalent bonds, such as dipole-dipole interaction, hydrogen bonding and ion bonding. The high molecular compound is more preferably a copolymer, which is a solid at room temperature and under normal pressure and shows physical properties of undergoing neither rupture or plastic deformation in an elongation range of from 0 to 15% at 20° C. and 65% R.H., or a copolymer which contains hydrophilic segments and are soluble or dispersible in water or a lower alcohol. Notably, the high molecular compound can be a copolymer which contains hydrophilic segments and an organopolysiloxane segment.
Such a high molecular compound may desirably be soluble or completely dispersible in water or a lower alcohol, in other words, a high molecular compound whose crosslinks are readily cleaved in water or a lower alcohol. The term “lower alcohol” as used herein preferably means a C
1
-C
6
alcohol.
Examples of the bonds other than covalent bonds include bonds which are readily cleaved in water or a lower alcohol, for example, ionic bonds, hydrogen bonds, hydrophobic interactions, dipole-dipole interactions, and bonds by van der Waals force, with ionic
Fujiwara Kana
Oda Takashi
Rindo Katsuhiko
Suzuki Hirohisa
Tanaka Nobushige
Kao Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Venkat Jyothsna
LandOfFree
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