Drug – bio-affecting and body treating compositions – Live skin colorant containing – Lip
Reexamination Certificate
1999-07-01
2003-08-26
Travers, Russell (Department: 1617)
Drug, bio-affecting and body treating compositions
Live skin colorant containing
Lip
C424S069000, C424S401000, C424S497000, C424S078170, C424S078310, C424S078350
Reexamination Certificate
active
06610278
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a powder-based solid cosmetic composition which has excellent skin feel upon use and is not broken easily by an external force.
2. Description of the Related Art
A powder-based solid cosmetic composition is generally prepared by a press molding method, wherein a raw material composition in a container is solidified by compaction. However, typical powder-based solid cosmetic compositions are poorly bound together, i.e., have poor powder-powder binding power, owing to a relatively small content of an oil component. As a result, high pressure is required to press-mold the solid composition, and the resultant product is necessarily hard and is powdery to the touch.
Generally, the lower the hardness of a powder-based solid cosmetic composition, the lower the powder-powder binding power, and the product is easily broken by an external force.
On the other hand, a solvent method is known which includes mixing a cosmetic composition with a low-boiling-point organic solvent, filling the resulting mixture in the form of a slurry into a container, and then solidifying the composition by removing the solvent (Japanese Patent Application Laid-Open No. Sho 56-108703). Although the solvent method is advantageous because the mixture can be uniformly filled into the container, several problems are associated with the solvent method: shrinkage or cracks appear during drying owing to the evaporation of a large amount of the solvent from the slurry, the filling has a tendency to break, and caking occurs after molding.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a powder based solid cosmetic composition which has excellent skin feel upon use and is resistant to cracks.
The present inventors have found that a powder-based solid cosmetic composition which has excellent skin feel upon use and is resistant to cracks is available by adjusting each of its hardness, porosity and impact resistance to a predetermined value.
One embodiment of the present invention provides a powder-based solid cosmetic composition having a hardness not greater than 75 as measured by an “Asker rubber hardness meter type C1L”, a porosity of at least 0.4 and an impact resistance of at least 5.
Another embodiment provides a process for the preparation of the above-described powder-based solid cosmetic composition, which includes mixing powder, a binder including a film-forming polymer having a modulus of elasticity not greater than 200 kg/cm
2
and a volatile solvent and then solidifying the resulting mixture by volatilizing the volatile solvent.
The present invention provides a powder-based solid cosmetic composition which has excellent skin feel upon use. More particularly, the composition of the present invention has a moisturized feeling, is smooth and permits easy release of powder from the molded product upon use. In addition, the composition of the present invention is free from cracks and is not easily broken by an external force. The powder-based solid cosmetic composition of the present invention is particularly suitable as make-up or a cosmetic such as foundation, face powder, cheek rouge or eye shadow.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description, which is given for illustration of the invention and is not intended to be limiting unless otherwise specified.
Preferably, from the viewpoint of the feeling upon use and cracks, the powder-based solid cosmetic composition has a hardness not greater than 75, particularly 10 to 75, and more particularly, 20 to 75, as measured by an “ASKER rubber hardness meter type C1L” (trade name), a porosity of at least 0.4, particularly 0.45 to 0.7, and more particularly 0.5 to 0.65, and an impact resistance (as defined below) of at least 5, particularly at least 7, and more particularly at least 8. Among said powder based solid cosmetic compositions are included a foundation having a hardness of 10 to 70, particularly 10 to 65, and an eye shadow having a hardness of 30 to 75, particularly 50 to 75.
The hardness of the molded product is measured directly by an ASKER rubber hardness tester type C1L. In the below-described preparation examples, the hardness was measured using a sample which had been filled in an aluminum pan having a diameter of 54 mm and depth of 4 mm, molded and then dried. The porosity was determined in accordance with the below-described equation based on the measuring results of the weight and volume of the molded product and true density of the powder.
Porosity
=
1
-
Weight
of
molded
product
True
density
of
the
powder
×
1
Volume
of
molded
produc
In the above formula, the term “molded product” means a cosmetic composition after molding and drying. True density of the powder was measured using “ACCUPUR Model 1330” (trade name: product of Shimadzu Corporation) for the powder mixture used.
Impact resistance was evaluated based on the number of dropping times until a crack appeared in the molded product when it was repeatedly dropped from a height of 50 cm onto a plywood board of 25 mm thick.
In the present invention, it has been found that a powder-based solid cosmetic composition satisfying the above-described conditions exhibits desired performances, the powder-based solid cosmetic composition preferably comprising powder and a film-forming polymer having a modulus of elasticity preferably not greater than 200 kg/cm
2
.
The film-forming polymer to be used in the present invention preferably has a modulus of elasticity not greater than 200 kg/cm
2
, with 1 to 100 kg/cm
2
being particularly preferred and with 5 to 75 kg/cm
2
being most particularly preferred. When the modulus of elasticity exceeds 200 kg/cm
2
, the product is inferior in softness or smoothness, leading to a deterioration in the feeling upon use.
In the present invention, the modulus of elasticity was measured as follows:
A 10 wt. % solution or dispersion of each film-forming polymer was weighed in a TEFLON Petri dish having a diameter of 5 cm, and naturally dried for 5 to 10 days. The film so obtained (having a thickness of 0.3 to 0.5 mm) was cut into strips 15 mm long and 5 mm wide and each was used as a sample for the measurement. After allowing a sample to stand at 25° C. and relative humidity of 30% for at least 24 hours, the sample was fixed to a tensile test jig of a dynamic viscoelasticity measuring apparatus (“RHEOSPECTRA DVE-V4” trade name; product of UBM) and measured at an oscillation frequency of 10 Hz and an amplitude of 10 &mgr;m.
Preferably, film-forming polymers satisfying the above-described requirement for the modulus of elasticity have a molecular weight of about 10,000 to 1,000,000, more preferably, 15,000 to 900,000, and most preferably, 20,000 to 800,000. Preferred examples include vinyl polymers obtained by the polymerization of at least one moment having a polymerizable double bond, poly (N-acylalkyleneimine)modified silicones and vinyl silicone block polymers. Preferred examples of monomers having a polymerizable double bond include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid; unsaturated carboxlic esters such as hydroxyethyl (meth)acrylate and polyethylene glycol mono (meth)acrylate; unsaturated carboxylic amides such as (meth)acrylamide and N-diacetonacrylamide; amino-containing unsaturated carboxylic esters and salts therof such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate and N,N,N-trimethylaminoethyl (meth)acrylate; aromatic vinyl compounds such as styrene, a-methylstyrene, chlorostyrene and alkylstyrene; acrylic esters and methacrylic esters such as met
Kao Corporation
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Travers Russell
Wang Shengjun
LandOfFree
Powder-based solid cosmetic composition and preparation... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Powder-based solid cosmetic composition and preparation..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Powder-based solid cosmetic composition and preparation... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3096163