Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Cosmetic – antiperspirant – dentifrice
Reexamination Certificate
1999-07-30
2002-08-06
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Cosmetic, antiperspirant, dentifrice
C424S059000, C424S069000, C424S068000, C424S070210
Reexamination Certificate
active
06428795
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition for external use (hereinafter referred to as an external-use composition), and more particularly, to an external-use composition useful as a cosmetic composition.
2. Background Art
Conventionally, a spherical powder of an organopolysiloxane elastomer, having characteristic elasticity, has been developed as a powder for cosmetic compositions and has been incorporated into a variety of products. Such a powder exhibits favorable properties when incorporated into cosmetic compositions, i.e., the cosmetic composition containing such a powder exhibits good skin fittability and spreadability on the skin; imparts a light and smooth sensation when applied by rubbing; has a soft-touch sensation; and imparts no strange sensation or irritation to the skin (Japanese Patent Application Laid-Open (kokai) No. 2-243612 and Japanese Patent Publication (kokoku) Nos. 4-17162 and 4-66446).
Meanwhile, a gelling agent for an oily ingredient is used in order to thicken an oily ingredient in an external-use composition. Conventionally, gelling agents such as metallic soap, organic-compound-modified clay minerals, and oil-soluble polymers have been known to gel hydrocarbon oils and ester oils. However, hydrocarbon oils and ester oils per se are sticky and oily, and such drawbacks limit use thereof in an external-use composition, even though gelling agents therefor are available.
In contrast, silicone oils, having favorable characteristics such as a light sensation for use and an non-sticky touch to the skin, has been widely used in external-use compositions in recent years. However, few gelling agents for gelling silicone oil are known; an example of which is a certain type of polyether-modified silicone disclosed in Japanese Patent Application Laid-Open (kokai) No. 7-215817. In addition, a gel-type composition in which silicone oil is gelled by use of the polyether-modified silicone exhibits slight stickiness which is characteristic to polymers.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide an external-use composition imparting no sticky sensation in use, particularly an external-use composition for cosmetic compositions exhibiting excellent retention on the skin during use (hereinafter called “cosmetic retention”), by finding a gelling agent for an oily ingredient, particularly for silicone oil.
In order to overcome the drawbacks, the present inventors have conducted earnest studies on a spherical powder of organopolysiloxane elastomer, and have found that a spherical powder of organopolysiloxane elastomer having a JIS A hardness as low as 1.0-30 has excellent oil-absorbability and serves as a gelling agent for an oily ingredient, particularly silicone oil, as compared with a conventionally used spherical powder of organopolysiloxane elastomer having a JIS A hardness of 35-80.
The inventors have also found that an external-use composition containing such a spherical powder of organopolysiloxane elastomer having excellent oil-absorbability imparts no sticky sensation in use and exhibits further improved skin fittability and spreadability on the skin; and imparts a further improved light and smooth sensation when applied by rubbing (hereinafter referred to as light and smooth application sensation), as compared with a conventionally used spherical powder of organopolysiloxane elastomer having a JIS A hardness of 35-80, and has excellent stability with the passage of time. Particularly, when the composition serves as a cosmetic composition, the cosmetic composition exhibits excellent cosmetic retention. The present invention has been accomplished based on this finding.
Accordingly, in one aspect of the present invention, there is provided an external-use composition containing a spherical powder of organopolysiloxane elastomer having a JIS A hardness of 1.0-30 that has a mean particle size of 0.1-200 &mgr;m.
Preferably, the external-use composition contains the spherical powder of organopolysiloxane elastomer in an amount of 0.1-50.0 wt. % based on the entirety of the composition.
Particularly, the external-use composition is suitable for cosmetic compositions.
As used herein, the term “mean particle size” refers to a value which is obtained by measuring the diameters in a specific direction of particles under an optical microscope and dividing the sum of respective diameters of particles by the number of measured particles.
The term “JIS A hardness” refers to a hardness measured according to JIS K 6301 by use of the JIS A hardness meter.
The present invention provides an external-use composition having excellent spreadability on the skin, good light and smooth application sensation and skin fittability, and non-sticky sensation in use. Particularly, the present invention provides a cosmetic composition having greatly improved cosmetic retention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Modes for carrying out the present invention will next be described.
The spherical powder of organopolysiloxane elastomer which is incorporated into the external-use composition of the present invention is composed of an organopolysiloxane elastomer having a JIS A hardness of 1.0-30, preferably 1.0-10. When the JIS A hardness is less than 1.0, the external-use composition containing the powder disadvantageously imparts a sticky sensation in use, whereas when the hardness is in excess of 30, gelling property of the powder is unfavorably markedly deteriorated.
The spherical powder of organopolysiloxane elastomer that is incorporated into the external-use composition of the present invention has a mean particle size of 0.1-200 &mgr;m, preferably 0.5-20.0. When the particle size is less than 0.1 &mgr;m, a smooth application sensation disadvantageously disappears, whereas when the particle size is in excess of 200 &mgr;m, the powder causes an unfavorable rough sensation when applied by rubbing.
The spherical powder of organopolysiloxane elastomer which is incorporated into the external-use composition of the present invention may be a perfectly spherical powder or an oblate spherical powder. However, a perfect spherical powder is more preferable in that the composition containing the powder imparts a more favorable smoother application sensation.
No particular limitation is imposed on the method for producing the spherical powder (having a mean particle size of 0.1-200 &mgr;m) of organopolysiloxane elastomer having a JIS A hardness of 1.0-30, and the powder can generally be produced by use of a curable organopolysiloxane composition as a raw material. Examples of the curable organopolysiloxane composition include:
an addition-curable organopolysiloxane composition which is cured through addition reaction between a diorganopolysiloxane having a silicon-bonded hydrogen atom and an organopolysiloxane having a silicon-bonded lower alkenyl group such as a vinyl group conducted in the presence of a platinum catalyst;
a condensation-curable organopolysiloxane composition which is cured through dehyrogenation reaction between a diorganopolysiloxane having hydroxyl groups at both molecule ends and a diorganopolysiloxane having a silicon-bonded hydrogen atom conducted in the presence of an organotin compound;
a condensation-curable organopolysiloxane composition which is cured through condensation reaction, such as dehydration or removal of alcohol, oxime, amine, amide, carboxylic acid, ketone, etc., between a diorganopolysiloxane having hydroxyl groups at both molecule ends and hydrolyzable organosilanes conducted in the presence of an organotin compound or titanate;
a peroxide-curable organopolysiloxane composition which is cured by the application of heat in the presence of an organic peroxide catalyst; and
a high-energy-ray-curable organopolysiloxane composition which is cured through radiation of &ggr;-rays, UV-rays, or an electron beam.
Among these curable organopolysiloxane compositions, an addition-curable organopolysiloxane composition is preferred, in view of a high c
Miura Yoshimasa
Suzuki Fukuji
Takahashi Kazuo
Takata Sadaki
LandOfFree
Skin treatment composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Skin treatment composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Skin treatment composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2953653