WO2013031030A1

WO2013031030A1 - Cosmetic sheet

Info

Publication number: WO2013031030A1
Application number: PCT/JP2011/070413
Authority: WO
Inventors: Kazuyuki Ohnishi; Jean-Pascal Hirt
Original assignee: L'oreal
Priority date: 2011-09-01
Filing date: 2011-09-01
Publication date: 2013-03-07

Abstract

The present invention relates to a cosmetic sheet comprising: at least one substrate comprising at least one gel-forming material; and at least one aqueous medium comprising 200 ppm or more, preferably 1,000 ppm or more, and more preferably 1,500 ppm or more, of carbon dioxide which is dissolved in the aqueous medium. The cosmetic sheet according to the present invention can provide sufficient cosmetic effects due to the maintenance of a relatively high concentration of CO₂for a long time, and can well fit to the skin, the lips and the like of a user, and therefore, it can be used easily, and can provide a comfortable feeling on use.

Description

DESCRIPTION COSMETIC SHEET TECHNICAL FIELD

The present invention relates to a cosmetic sheet for the skin, the lips and the like, and a package including the cosmetic sheet, as well as a cosmetic process using the cosmetic sheet.

BACKGROUND ART

The use of C0₂ (carbon dioxide) for cosmetic treatments of the human body is already known. For example, C0₂ can improve blood flow, so that it can exert slimming effects. In addition, it is believed that C0₂ can improve the relief pattern of the skin, make pores on the skin less noticeable, treat acnes and pimples on the skin, make the skin bright and/or white, and/or improve the skin conditions (e.g., by firming, elasticizing or tightening).

JP-A-2000-319187 discloses a composition which can be used for slimming and comprises water, a thickening agent, and C0₂ bubbles. The composition is applied onto the skin for the transdermal provision of C0₂.

However, under normal atmospheric pressure, the C0₂ bubbles can easily evaporate into the air from the composition. Therefore, the blood flow improvement effects due to the above composition were insufficient.

On the other hand, JP-B-3633930 discloses applying a first

nonwoven fabric sheet including an acid and water onto the skin, and applying a second nonwoven sheet including a carbonate onto the first nonwoven fabric sheet to generate C0₂ of the non-bubble type.

However, the blood flow improvement effects by the above first and second nonwoven fabric sheets were still insufficient,

because C0₂ gas can easily evaporate through the nonwoven fabric sheets even though the C0₂ is not in the form of bubbles.

In addition, the nonwoven fabric sheets may be difficult to fit to the skin, in particular, uneven skin such as that of a face, and the lips. Furthermore, when a user is standing or sitting up, the adhesion power of the nonwoven fabric sheets to the skin or the lips may be insufficient, and they may slip down from the skin or the lips.

JP-B-3633930 also discloses a laminated sheet in which the above second nonwoven fabric sheet is covered with a plastic film such as a polyethylene film through which C0₂ cannot penetrate.

However, in general, a plastic film in a laminated sheet adheres to a nonwoven fabric sheet with the aid of an adhesive or a heat treatment. Therefore, the laminated sheet including the second nonwoven fabric sheet covered with the plastic film is stiff and difficult to fit to the skin, in particular uneven skin such as that of a face.

DISCLOSURE OF INVENTION

An objective of the present invention is to provide a cosmetic sheet which can well prevent or reduce the evaporation of C0₂ to the atmosphere, so that it can provide sufficient cosmetic effects due to a relatively high concentration of C0₂ for a long time .

Another objective of the present invention is to provide a cosmetic sheet which can well fit to the skin, the lips and the like of a user, and therefore, it can be used easily, and can provide a comfortable feeling on use.

The above objectives of the present invention can be achieved by a cosmetic sheet comprising:

at least one substrate comprising at least one gel-forming material; and

at least one aqueous medium comprising 200 ppm or more,

preferably 1,000 ppm or more, and more preferably 1,500 ppm or more, of carbon dioxide which is dissolved in the aqueous medium.

The pH of the aqueous medium may be 8.0 or less, preferably 7.0 or less, and more preferably 6.0 or less.

The carbon dioxide may have been made to dissolve to the aqueous medium by contacting the aqueous medium with the carbon dioxide with a high pressure of from 0.1 to 1 MPa, preferably 0.1 to 0.8 MPa, and more preferably 0.1 to 0.5 MPa.

The substrate may be in the form of a gel. The cosmetic sheet may not comprise any woven or nonwoven fabric. The term "fabric" here means an aggregate of normal cellulose fibers from plant origin. It is preferable that the normal cellulose fibers have a diameter of 500 nm or more, more

preferably 1 um or more, and further more preferably 10 μπι or more. Thus, the scope of "fabric" here includes not only normal textile but also paper.

It is preferable that the gel-forming material be selected from polysaccharides .

It is preferable that the polysaccharide be alginic acid or a salt thereof.

It is also preferable that the polysaccharide be cellulose produced by at least one microorganism. Each cellulose may preferably comprise cellulose microfibrils. The cellulose microfibril may have a diameter of 1 to 100 nm, preferably 2 to 50 nm, and more preferably 3 to 10 nm. It is preferable that the cellulose microfibrils form a network structure.

The thickness of the substrate may be 0.01 mm to 5 mm, preferably 0.05 mm to 3 mm, and more preferably 0.1 mm to 2 mm.

It is preferable that the substrate comprise at least a part of the aqueous medium.

The present invention also relates to a cosmetic process for the treatment of the skin or the lips, comprising a step of applying onto the skin or the lips at least one cosmetic sheet according to the present invention. The treatment may be slimming,

improving the relief pattern of the skin, making pores on the skin less noticeable, treating acnes and pimples on the skin, making the skin bright and/or white, and/or improving the skin conditions .

The present invention also relates to a package comprising at least one cosmetic sheet according to the present invention.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a front view of an example of a cosmetic sheet

according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION After diligent research, the inventors have discovered that it is possible to provide a cosmetic sheet which can well prevent or reduce the evaporation of C0₂ to the atmosphere, by combining an aqueous medium comprising dissolved C0₂ with a gel-based substrate.

Thus, the cosmetic composition according to the present invention is characterized by comprising:

at least one substrate comprising at least one gel-forming

material; and

at least one aqueous medium comprising 200 ppm or more,

The cosmetic sheet according to the present invention can provide sufficient cosmetic effects due to the maintenance of a

relatively high concentration of C0₂ for a long time.

Furthermore, the cosmetic sheet according to the present

invention can fit well to the skin, even if the skin is uneven or has a nonlinear relief, as well as the lips of a user. Therefore, it can be used easily, and can provide the user with a

comfortable feeling on use.

The cosmetic sheet according to the present invention can be composed of a single sheet, and does not need to be prepared by laminating a plurality of sheets with the use of an adhesive or a heat treatment. Therefore, the cosmetic sheet according to the present invention can be prepared easily. Even if the cosmetic sheet according to the present invention is composed of a single sheet, it can have a good C0₂-sealing capability.

The cosmetic sheet according to the present invention is flexible. Therefore, even if the cosmetic sheet according to the present invention is in the form of a laminated sheet, it can well fit to the skin of a user, even to uneven skin such as that of the face, or the lips of a user. Therefore, the cosmetic sheet according to the present invention can be used easily, and can provide a comfortable feeling on use.. In addition, the cosmetic sheet according to the present invention in the form of a laminated sheet can have a better C0₂-sealing capability.

Hereinafter, the cosmetic sheet according to the present

invention will be explained in a more detailed manner. ( Substrate )

The substrate according to the present invention comprises at least one gel-forming material.

It should be noted that the term "substrate" here means a support of the cosmetic sheet, that the substrate can be composed of a single layer or a plurality of layers. It is preferable that the substrate is composed of a single layer. It is possible that 80 wt%, preferably 90 wt%, and more preferably 100 wt% of the solid content of the substrate be derived from gel-forming material (s)

The "gel-forming material" means any substance which can form a gel. A single type of gel-forming material or a combination of different types of gel forming materials may be used.

The gel-forming material may be selected from any conventional substances which can form a gel. As examples of the substances which can form a gel, mention may be made of polysaccharides, polyvinyl alcohols, poly (meth) acrylic acids or derivatives thereof, polyacrylamides and derivatives thereof,

polyvinylpyrrolidones and derivatives thereof, polyvinylethers and derivatives thereof, and mixtures thereof.

It is preferable that the gel-forming material is selected from polysaccharides .

Polysaccharide is a carbohydrate in which two or more, preferably 10 or more, monosaccharides are linked via a glycoside bond. The polysaccharide used in the present invention may be a simple polysaccharide or a complex polysaccharide such as

mucopolysaccharide. A single type of polysaccharide may be used, or two or more types of polysaccharides may be used together.

As examples of gel-forming polysaccharides, mention may be made of starch, glycogen, cellulose, chitin, agarose, carrageenan, heparin, hyaluronic acid, pectin, xyloglucan, alginic acid, agar, guar gum, gum Arabic, karaya gum, quince seed gum, konjac mannan, tamarind seed gum, tara gum, dextrin, gum tragacanth, locust bean gum, cardollan, xanthan gum, jellan gum, dextran, pullulan, and derivatives thereof.

As the cellulose derivative ( s ) , mention may be made of, carboxy- methyl cellulose, sodium carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxyethylethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, sodium methyl cellulose, microcrystalline cellulose, sodium cellulose sulfate, and mixtures thereof. Carboxymethyl cellulose is preferable.

The cellulose derivative ( s ) may also be selected from alkyl celluloses. These polymers are obtained by grafting an alkyl residue onto one or more hydroxy groups of the cellulose polymer to form the hydroxyalkyl derivative. These alkyl residues may be selected from the following groups: stearyl, isostearyl, lauryl, myristyl, cetyl, isocetyl, cocoyl, palmityl, oleyl, linonyl, ricinolyl, behenyl, and mixtures thereof. These hydroxyalkyl cellulose derivatives may also be subjected to chemical

modification, e.g. using a carboxylic residue.

It is preferable that the gel-forming polysaccharide is selected from alginic acid, cellulose, and derivatives thereof.

As derivatives of alginic acid, an alginate (a salt of alginic acid) and a glycol alginate (a salt of glycol alginate) are preferable. Alginic acid, which is isolated from seaweed, is a polyuronic acid made up of two uronic acids: D-mannuronic acid and L-guluronic acid. The ratio of mannuronic acid and guluronic acid varies with factors such as seaweed species, plant age, and part of the seaweed (e.g., stem, leaf).

Alginic acid is substantially insoluble in water. However, it forms water-soluble salts with alkali metals, such as sodium, potassium, and, lithium; magnesium; ammonium; and the substituted ammonium cations derived from lower amines, such as methyl amine, ethanol amine, diethanol amine, and triethanol amine. The salts are soluble in aqueous media above pH 4, but are converted to alginic acid when the pH is lowered below about pH 4. A water- insoluble alginate is formed if certain polyvalent cations, especially calcium, barium, strontium, zinc, copper(+2), aluminum, and mixtures thereof are present in the medium at appropriate concentrations .

Water insoluble alginate salts, in which the principal cation is calcium, are found in the fronds and stems of seaweeds of the class Phaeophyceae, examples of which are Fucus vesiculosus,

Fucus spiralis, Ascophyllum nodosum, Macrocystis pyrifera, Alaria esculenta, Eclonia maxima, Lessonia nigrescens, Lessonia

trabeculata, Laminaria japonica, Durvillea antarctica, Laminaria hyperborea, Laminaria longicruris, Laminaria digitata, Laminaria saccharina, Laminaria cloustoni, and Saragassum sp. Methods for the recovery of alginic acid and its water-soluble salts,

especially sodium alginate, from natural sources are well known, and are described, for example, in Green, U.S. Pat. No. 2,036,934, and Le Gloahec, U.S. Pat. No. 2,128,551.

Alginate may be reacted with an alkylene oxide, such as ethylene oxide or propylene oxide, to form a glycol alginate. The glycol is bonded to the alginate through the carboxyl groups. Typically, an alginate is reacted with propylene oxide to form propylene glycol alginate (PGA) . Preparation of propylene glycol alginate is disclosed in Strong, U.S. Pat. No. 3,948,881, Pettitt, U.S.

Pat. No. 3,772,266, and Steiner, U.S. Pat. No. 2,426,125.

Preferably, the propylene glycol alginate has a degree of

esterification of about 40% to about 95%, more preferably about 70% to 95%.

Suitable alginates have a weight-average molecular weight of about 20,000 Daltons to about 500,000 Daltons. The weight- average molecular weight is calculated by first determining the intrinsic viscosity, then using the Mark-Houwink Sakurada

Equation, as in Martinsen, et al, "Comparison of Different

Methods for Determination of Molecular Weights and Molecular

Weight Distribution of Alginates" (Carbohydr. Polym., 15, 171-193, 1991) .

A list of various commercially available alginates, their

properties, and their sources is found in Shapiro, U.S. Pat. No. 6,334,968, Table 1, column 16, line 49, to column 17, line 18, incorporated herein by reference. Mixtures or blends of

alginates, for example alginates of different molecular weights and/or G content, may be used.

In particular, as the gel-forming polysaccharide, cellulose

produced by at least one microorganism is preferable.

The cellulose produced by the microorganism may be called "bio- cellulose". A single type of bio-cellulose may be used for the present invention. On the other hand, two or more types of bio- celluloses may be used together for the present invention.

As the microorganism, any microbe can be used as long as it can produce bio-cellulose. A single type of microorganism may be used, or two or more types of microorganisms may be used together. It is preferable to use at least one microbial strain of the genus Acetobacter, the genus Agrobacterium, the genus Rhizobium, the genus Sarcina, the genus Pseudomonas, the genus Achromobacter, the genus Alcaligenes, the genus Aerobacter, the genus

Azotobacter, the genus Gluconacetobacter, the genus Xanthomonas, the genus Bacillus, and the like. Acetobacter Xylinum among the genus Acetobacter, Gluconacetobacter xylinus or Hansenii among the genus Gluconacetobacter, Xanthomonas camperastris among the genus Xanthomonas, and Bacillus var Natto among the genus

Bacillus, are more preferable. Acetobacter Xylinum among the genus Acetobacter is most preferable.

The bio-cellulose can be produced by culturing at least one microorganism which can produce bio-cellulose, such as those listed above.

The mode of culturing the microorganism is not limited. For example, a static culture mode or a spinner culture mode may be employed. In the static culture mode, a microorganism which can produce bio-cellulose will be seeded on a culture medium and incubated at a temperature of, for example, from 10 to 40 °C, preferably from 25 to 40°C, and for a time period of, for example, from 1 to 60 days, preferably from 5 to 14 days. Thus, the cellulose produced by the microorganism will accumulate at the surface of the culture medium to form a cellulose membrane. The thickness of the cellulose membrane will increase as the culture of the microorganism proceeds. Thus, the cellulose membrane can be in the form of a sheet. It is preferable to employ the static culture mode, since the collection of the cellulose membrane or sheet is easy.

The conditions for culturing the microorganism are not limited either. For example, any type of culture medium can be used as long as it can increase the microorganism which can produce the bio-cellulose. It is typical that the culture medium includes sources of carbon, nitrogen, and the like, as well as inorganic salts, amino acids, vitamins and the like. It is possible to use a culture medium including natural ingredients from plants such as grains (for example, rice and wheat), vegetables (for example, cabbage and onion), and fruits (for example, orange and

pineapple) , because the obtained bio-cellulose may have less odor, and the culture medium can be handled safely. On the other hand, it is also possible to use a culture medium including semi- natural or non-natural ingredients such as purified or modified natural ingredients (e.g., purified sugars) or chemicals (e.g., synthesized sweetners). The pH of the culture medium can be adjusted depending on the type of the microorganism. It is possible that the pH of the culture medium is from 2 to 9.

However, it is preferable that the pH of the culture medium is from 2.5 to 7, and more preferably 3 to 5, because the

proliferation of saprophytic bacteria in the culture medium can be controlled.

The bio-cellulose comprises cellulose microfibrils. Each

cellulose microfibril has a diameter of 1 to 100 nm, preferably 2 to 50 nm, and more preferably 3 to 10 nm. The cellulose

microfibrils can form a network structure wherein microfibrils are entwined with each other. It is preferable that the network structure is dense, in view of the strength of the bio-cellulose.

The cellulose fibers of a woven or non-woven cotton fabric sheet or even a paper sheet have a micron-order diameter such as 10 to 100 μπι. On the other hand, the cellulose microfibrils are very fine such that they have a nano-order diameter such as 2 to 100 nm. Therefore, the macroscopic appearance of bio-cellulose is not similar to that of a woven or non-woven cotton fabric sheet or a paper sheet. Rather, bio-cellulose appears like agar or gelatin. Therefore, in the field of foods, bio-cellulose is well-known as the material of "nata de coco".

It is preferable to wash the bio-cellulose obtained just from a culture medium with water, because the microorganism can be removed, and because it may include the ingredients in the culture medium or organic acids derived from the microorganism ( s ) in the culture medium. In particular, the bio-cellulose obtained from the genus Acetobacter may include acetic acid. Therefore, it is possible to treat the bio-cellulose with alkali such as a sodium hydroxide aqueous solution. After treating the bio- cellulose with alkali, for safety reasons, the bio-cellulose may be treated with acid in order to neutralize the pH.

Alternatively, it is also preferable to wash the bio-cellulose with water without treating it with acid until the pH of the water becomes to the neutral range.

Bio-cellulose can contain water. Therefore, the cosmetic sheet according to the present invention can preferably contain water. The cosmetic sheet according to the present invention which includes water can also have moisturizing or hydrating effects for the skin and the lips by alleviating dryness and wrinkles thereon . In addition, bio-cellulose has a unique feeling on touch, such as a cool feeling. Thus, the cosmetic sheet according to the present invention can provide a comfortable feeling on use based on the unique feeling on touch based on the bio-cellulose.

In addition, the cellulose produced by microorganism ( s ) is relatively strong. For example, it has a high tensile strength as compared to other natural polymers such as polyglutamic acid. Accordingly, the cosmetic sheet according to the present

invention may not be broken but kept adhered onto the skin even though the skin moves when, for example, exercising.

The substrate used in the cosmetic sheet according to the present invention has no or substantially small carbon dioxide

permeability. Therefore, the cosmetic sheet according to the present invention can prevent or reduce the evaporation of C0₂ to the atmosphere, and can provide sufficient cosmetic effects due to a relatively high concentration of C0₂.

In addition, since the substrate comprising at least one gel- forming material such as polysaccharide, in particular alginate or cellulose produced by microorganism ( s ) , has high flexibility, especially when combined with water, the cosmetic sheet according to the present invention can suitably fit the skin, even the skin of a face, or the lips which has or have complicated surfaces and does or do not have a flat surface. Therefore, the cosmetic sheet according to the present invention can be used easily even when a user is standing or sitting up.

It is more preferable that the substrate is in the form of a gel, because the substrate can have more flexibility. The gel

preferably contains water.

If necessary, at least one gelling agent can be used to form a gel. A single type of gelling agent may be used, or two or more types of gelling agents may be used together. In particular, when alginic acid or a derivative thereof such as alginate is used, a gelling agent or agents can preferably be used. A gelling agent or agents may be added to a gel-forming

polysaccharide such as alginate preferably dissolved or dispersed in an aqueous medium to form a gel.

The gelling agent may comprise a polyvalent cation, typically a divalent and/or a trivalent cation, or a mixture of polyvalent cations capable of gelling the gel-forming polymer. Suitable polyvalent cations include, for example, calcium(2+), barium(2+), strontium(2+ ) , iron(2+ ), zinc (2+) , copper (2+ ) , and aluminum ( 3+) . Preferred cations are divalent metal cations, more preferably the calcium (2+) cation.

A salt or combination of salts that provides the desired gelling polyvalent cation or mixture of polyvalent cations can be used as the gelling agent. The gelling agent may be insoluble in water, but releases an ion capable of forming a gel in an acidic

solution, typically at a pH of 3 or higher. Alternatively, the gelling agent may be soluble in water but the ion capable of forming a gel is complexed and becomes available only under acidic conditions. Useful gelling agents include salts, such as the following, their hydrates, and mixtures thereof: calcium carbonate, calcium disodium edetate, calcium oxalate, dicalcium phosphate, tricalcium phosphate, tricalcium citrate, strontium carbonate, barium carbonate, cupric carbonate, zinc carbonate, zinc oxalate, and zinc phosphate.

Preferred gelling agents are those that also provide a buffering effect and/or consume acid when the polyvalent cation is released. These include for example, bicarbonates , carbonates, and

phosphates, preferably carbonates. A preferred gelling agent, especially for alginate, pectin and carrageenan, is calcium

carbonate. Aluminum ions are useful for gelling glycol alginates, which typically do not gel with calcium ions.

The gel may be foamed. Thus, at least one foaming agent can be used to foam the gel. A single type of foaming agent may be used, or two or more types of foaming agents may be used together. In particular, when alginic acid or a derivative thereof such as alginate is used, a foaming agent or agents can preferably be used. A foaming agent or agents may be added together with the gelling agent (s) to a gel-forming material, in particular a polysaccharide such as alginate, preferably dissolved or

dispersed in an aqueous medium, to form a foamed gel. The

foaming agent may be a polymeric foaming agent, a surfactant, or a mixture thereof.

Polymeric foaming agents, such as surface active hydrocolloids , are generally preferred because they are harder to leach from the resulting gelled foam than surfactants. Examples of surface active hydrocolloids include methyl cellulose, hydroxy propyl methyl cellulose (HPMC) , hydroxy propyl cellulose (HPC) , and hydroxy ethyl cellulose (HEC) .

The polymeric foaming agent is preferably soluble in water so that a homogeneous gelled foam is produced. A preferred water soluble foaming agent is hydroxy propyl methyl cellulose.

Hydroxy propyl methyl cellulose produces small bubbles that last until gelation occurs.

Surfactants are well known to those skilled in the art and are described, for example, in McCutcheon's Detergents, and

Emulsifiers, and Laughlin, U.S. Pat. No. 3,929,678, incorporated herein by reference.

Nonionic surfactants are typically condensation products of a hydrophobic organic aliphatic or alkyl aromatic compound and hydrophilic ethylene oxide and/or propylene oxide. The length of the resulting polyether chain can be adjusted to achieve the desired balance between the hydrophobic and hydrophilic

properties. Nonionic surfactants include, for example,

ethoxylates of alkyl phenols containing from about 8 to 18 carbon atoms in a straight- or branched-chain alkyl group, such as t- octyl phenol and t-nonyl phenol with about 5 to 30 moles of ethylene oxide, for example nonyl phenol condensed with about 9.5 moles of ethylene oxide, dinonyl phenol condensed with about 12 moles of ethylene oxide; ethoxylated and propoxylated alcohols, especially Cio-20 alcohols, with 2 to 100 moles of ethylene oxide and/or propylene oxide per mole of alcohol, especially

ethoxylates of primary alcohols containing about 8 to 18 carbon atoms in a straight or branched chain configuration with about 5 to 30 moles of ethylene oxide, for example, the ethoxylates of decyl alcohol, cetyl alcohol, lauryl alcohol, or myristyl

alcohol; ethoxylates of secondary aliphatic alcohols containing 8 to 18 carbon atoms in a straight or branched chain configuration with 5 to 30 moles of ethylene oxide; condensation of aliphatic alcohols containing about 8 to abut 20 carbon atoms with ethylene oxide and propylene oxide; polyethylene glycol and polyethylene oxide; ethoxylated castor oil (CRE OPHOR® CO 40); ethoxylated hydrogenated castor oil; ethoxylated coconut oil; ethoxylated lanolin; ethoxylated tall oil; ethoxylated tallow alcohol; and ethoxylates of sorbitan esters such as polyoxyethylene sorbitan monolaurate (TWEEN® 20), polyoxyethylene sorbitan monopalmitate (TWEEN® 40), polyoxyethylene sorbitan monostearate (TWEEN® 60), polyoxyethylene sorbitan monooleate (TWEEN® 80) , and

polyoxyethylene sorbitan trioleate (TWEEN® 85) . Examples of anionic surfactants are sodium stearate, sodium cetyl sulfate, sodium lauryl sulfate, ammonium lauryl sulfate,

triethanolamine lauryl sulfate, sodium myristyl sulfate, and sodium stearyl sulfate, triethanol amine dodecylbenzenesulfonate, sodium dodecylbenzene sulfonate, sodium polyoxyethylene lauryl ether sulfate, and ammonium polyoxyethylene lauryl ether sulfate. A preferred anionic surfactant is sodium lauryl sulfate (sodium dodecyl sulfate) .

Cationic surfactants include, for example, quaternary ammonium salts, such as cetyl trimethylammonium bromide, lauryl trimethyl ammonium chloride, alkyl benzyl methyl ammonium chlorides, alkyl benzyl dimethyl ammonium bromides, cetyl pyridinium bromide, and halide salts of quaternized polyoxyethylalkylamines .

Zwitterionic or amphoteric surfactants can also be used.

It is preferable that the substrate comprise water, preferably at least a part of the aqueous medium comprising dissolved C0₂ mentioned below. In this case, C0₂ can be provided gradually from the substrate so that the cosmetic effects due to the C0₂ can last for a long time.

The thickness of the substrate may vary. The thickness of the substrate can be, for example, from 0.01 mm to 5 mm, preferably from 0.05 mm to 3.0 mm, and more preferably from 0.1 to 2.0 mm.

(Aqueous Medium including Carbon Dioxide)

The cosmetic sheet according to the present invention comprises at least one aqueous medium comprising 200 ppm or more,

preferably 350 ppm or more, more preferably 500 ppm or more, further more preferably 1000 ppm or more, and even further more preferably 1500 ppm or more, of carbon dioxide which is dissolved in the aqueous medium.

Since C0₂ is dissolved in the aqueous medium in the present invention, and is not in the form of bubbles, the cosmetic sheet according to the present invention can prevent the C0₂ from being evaporated into the air.

The aqueous medium here means water or an aqueous solution including water and optionally at least one other ingredient such as a thickening agent and a cosmetic ingredient explained later. The content of water in the aqueous medium may be 50 to 100 wt%, preferably 60 to 95 wt%, and more preferably 70 to 90 wt%,

relative to the total weight of the aqueous medium.

It is preferable that the pH of the aqueous medium is 8.0 or less, preferably 7.0 or less, more preferably 6.0 or less, and further more preferably 5.0 or less. If the pH of the aqueous medium is 8.0 or less, C0₂ can be present in the aqueous medium mainly in the form of dissolved C0₂ without being transformed to a carbonate ion (C0₃ ^2~) or a bicarbonate ion (HC0₃ ^") . In order to improve blood flow, the use of C0₂ (not a carbonate ion or a bicarbonate ion) is preferable.

Carbon dioxide can be dissolved to the aqueous medium by any method.

For example, the aqueous medium can be contacted with carbon dioxide gas with a high pressure of from 0.1 to 1 MPa, preferably 0.1 to 0.8 MPa, and more preferably 0.1 to 0.5 MPa.

Since the solubility of C0₂ into water increases at a lower

temperature, it is preferable that the dissolution of C0₂ in the aqueous medium be performed at 30°C or less, preferably 25°C or less, and more preferably 20°C or less.

In one embodiment, an aqueous medium can be charged in a pressure bottle, and then C0₂ gas with a high pressure can be introduced into the pressure bottle. It is preferable that the aqueous medium have already been deaerated before being charged into the pressure bottle. As the pressure bottle, an autoclave may be used. If the viscosity of the aqueous medium is high, this

embodiment is preferable. It is preferable to agitate the

aqueous medium. As a means for agitating, any conventional

device such as a stirrer may be used.

In another embodiment, an aqueous medium and a high pressure C0₂ gas can be introduced into a static mixer under circulation. It is preferable that the aqueous medium have already been deaerated before going through the static mixer.

In another embodiment, an aqueous medium can be introduced into a hollow fiber module, and high pressure C0₂ can be provided to the hollow fiber module such that the C0₂ can penetrate into the aqueous medium via the wall of the hollow fiber. If the viscosity of the aqueous medium is low, this embodiment is preferable .

In another embodiment, dry ice may be put into an aqueous medium in a pressure bottle, and left for a while. It is preferable to agitate the aqueous medium. As a means for agitating, any conventional device such as a stirrer may be used.

The aqueous medium can comprise at least one thickening agent.

The type of thickening agent is not limited. A single thickening agent or a combination of two or more thickening agent may be used. As examples of the thickening agent, mention may be made of silicas, notably hydrophobic; clays such as montmorillonite, modified clays such as bentones for example, stearalkonium bentonite, stearalkonium hectorite; and the like.

The amount of thickening agent can range from 0.05 to 40 wt%, preferably from 0.5 to 20 wt%, and more preferably from 1 to 15 wt%, relative to the total weight of the aqueous medium.

The aqueous medium can comprise at least one cosmetic ingredient.

The cosmetic ingredient ( s ) may be water-soluble or liposoluble.

The water-soluble cosmetic ingredient ( s ) may be chosen from the following compounds: ascorbic acid and its biologically- compatible salts, enzymes, antibiotics, tightening agents, a- hydroxy acids and their salts, hydroxylated polyacids, sucroses and their derivatives, urea, amino acids, oligopeptides, water- soluble plant extracts and yeast extracts, protein hydrolysates , hyaluronic acid, mucopolysaccharides, vitamins B₂, B₆, H, PP, panthenol, folic acid, salicylic acetyl acid, allantoin,

glycyrrhetic acid, kojic acid, and hydroquinone .

The liposoluble cosmetic ingredient ( s ) may be chosen from the following compounds: d- -tocopherol , dl-a-tocopherol, 1-a- tocopherol, dl-a-tocopherol acetate, ascorbyl palmitate, vitamin F and glycerides of vitamin F, vitamin D, vitamin D₂, vitamin D₃, retinol, retinol esters, retinol palmitate, retinol propionate, β-carotene, d-panthenol, farnesol, and farnesyl acetate;

keratolytics such as salicylic acid, its salts and its esters, n- octanoyl-5 salicylic acid and its esters, a-hydroxyacid

alkylesters such as citric acid, lactic acid, glycolic acid, asiatic acid, madecassic acid, asiaticoside, total extract of centella asiatica, β-glycyerrhetinic acid, a-bisabolol, and ceramides such as 2 oleoylamino-1, 3 octadecane, phytanetriol, milk sphingomyelin, phospholipids of marine origin rich in polyunsaturated essential fatty acids, and ethoxyquin, rosemary extract, melissa extract, quercetin, extract of dried microalgae, and steroid anti-inflammatory agents.

The aqueous medium may comprise additional cosmetic active ingredients which are commonly used in cosmetics. Among the cosmetic active ingredients to be used, mention may be made of anti-oxidant cleansing agents, free radical scavengers,

moisturizers, depigmenting agents, liporegulators, anti-acne agents, antidandruff agents, anti-aging agents, softeners, antiwrinkle agents, keratolytic agents, anti-inflammatory agents, fresheners, healing agents, vascular protectors, antibacterial agents, antifungal agents, antiperspirants, deodorants, skin conditioners, anesthetics, immunomodulators, nourishing agents, and sebum absorbers (e.g. Orgasol) or moisture absorbers.

The amount of the cosmetic ingredient agent or the additional cosmetic active ingredient can range from 0.01 to 50 wt%,

preferably from 0.1 to 30 wt%, and more preferably from 1 to 10 wt%, relative to the total weight of the aqueous medium.

(Cosmetic Sheet)

The cosmetic sheet according to the present invention can be prepared by combining the above substrate and the above aqueous medium.

For example, the substrate can be immersed in the aqueous medium in order for the substrate to absorb at least a part of the aqueous medium. If the viscosity of the aqueous medium is high, the cosmetic sheet can be prepared by applying the aqueous medium onto the substrate.

The shape of the cosmetic sheet according to the present

invention is not limited. However, since the cosmetic sheet according to the present invention may preferably be used for cosmetically treating the face skin or the lips, it is preferable that the shape of the cosmetic sheet according to the present invention is such that it can cover the face or the lips of a user . Since the face is symmetric in terms of the center longitudinal axis of the face, it is preferable for the shape of the cosmetic sheet according to the present invention have C_2v symmetry such as a general oval shape.

Fig. 1 shows a front view of an example of a cosmetic sheet according to the present invention.

The cosmetic sheet shown in Figure 1 is intended to be applied onto the face, and is formed by a single substrate sheet (1) having holes (2,2) for the eyes, a hole (3) for the nose, and a hole (4) for the mouth. Any of the holes (2,2,3,4) may be replaced with slit(s) to uncover the eyes, nose and/or mouth.

The substrate sheet (1) may have a tab or tabs, preferably on the outline thereof, for facilitating the handling of the cosmetic sheet.

The dotted and dashed line (C) in Figure 1 corresponds to a longitudinal center line of the substrate sheet (1). The

longitudinal center line (C) shown in Figure 1 defines a center line of the substrate sheet (1) and is positioned to pass over the hole (3) for the nose as well as the hole (4) for the mouth. The longitudinal center line (C) shown in Figure 1 functions as a longitudinal symmetric axis for the substrate sheet (1) .

The cosmetic sheet shown in Figure 1 can be applied to the face to cover the skin such that the aqueous medium can contact the skin .

The cosmetic sheet according to the present invention may be used for any part of the body such as legs or waist. In such a case, the shape of the cosmetic sheet according to the present

invention is arbitrary.

The cosmetic sheet according to the present invention may consist of a substrate, or may comprise the substrate and one or more additional layers thereon.

If the cosmetic sheet according to the present invention consists of the substrate, the substrate may contain the above cosmetic ingredient ( s) .

On the other hand, if the cosmetic sheet according to the present invention comprises at least one additional layer in addition to the substrate, the additional layer and/or the substrate may contain the above cosmetic ingredient (s) .

The material of the additional layer (s) is not limited, and therefore any material can be used for preparing the additional layer (s). Two or more different materials may be used.

The material of the additional layer (s) may be a woven or non- woven fabric made of natural fibers such as cotton, pulp, bamboo and paper cellulose fibers, semi-natural fibers such as viscose rayon fibers and synthetic fibers such as polyester fibers, polyethylene terephthalate fibers, polyethylene fibers, and polypropylene fibers. Two or more selected from the above fibers may be used in combination.

Alternatively, the material of the additional layer (s) may be a film or sheet made from at least one selected from synthetic polymers such as polyethylenes and polyvinylalcohols , semisynthetic polymers such as alginates, and natural polymers such as polypeptides (e.g., γ-polyglutamic acid) and proteins (e.g., gelatin and collagen) . The film or sheet may be in the form of a gel or a jelly which may be transparent, translucent or opaque. Two or more selected from the above substances may be used in combination .

If the cosmetic sheet according to the present invention

comprises a plurality of additional layers, the material of each additional layer may be the same or different from each other. For example, the additional layers may be prepared by laminating the above film or sheet made from a synthetic polymer, a semisynthetic polymer and/or a natural polymer on the above woven or non-woven fabric.

The thickness of the additional layer is not limited. The thickness of the additional layer can be, for example, from 1 nm to 2.0 mm, preferably from 10 nm to 1.0 mm, and more preferably from 100 nm to 0.5 mm.

The cosmetic sheet according to the present invention with the above additional layer (s) can be prepared by, for example, applying a gel-forming material onto the additional layer (s), or applying the additional layer (s) onto a gel forming material.

For example, if the gel-forming material is bio-cellulose, the cosmetic sheet according to the present invention with the above additional layer(s) can be prepared by, for example, culturing microorganism to produce the bi-cellulose on the additional layer (s) .

However, the cosmetic sheet according to the present invention is preferably composed of only a substrate, because it is easy to prepare the cosmetic sheet, and the flexibility of the cosmetic sheet will be enhanced. Accordingly, for example, the cosmetic sheet according to the present invention may not comprise any woven or nonwoven fabric.

The cosmetic sheet according to the present invention may be contained in a container to prepare a package. The container may preferably be a bag or sack made from any material, preferably a plastic or metal film. An aluminum foil, in particular a

laminated aluminum foil, is more preferable as the material of the bag or sack. Thus, the present invention relates to a package comprising the cosmetic sheet according to the present invention. If necessary, the cosmetic sheet according to the present invention may be folded.

It is preferable that the above package comprising the cosmetic sheet according to the present invention further contains a cosmetic composition, preferably in the form of a liquid,

including at least one cosmetic ingredient as explained above.

(Cosmetic Process)

The cosmetic sheet according to the present invention can be used for a cosmetic process for beautifying the skin or the lips.

Thus, the cosmetic process according to the present invention is intended for treating the skin, preferably the skin of the face, or the lips, comprising a step of applying onto the skin or the lips at least one cosmetic sheet according to the present

invention as explained above.

The cosmetic process according to the present invention can preferably be intended for slimming, improving the relief pattern of the skin, making pores on the skin less noticeable, treating acnes and pimples on the skin, making the skin bright and/or white, and/or improving the skin conditions. For example, the cosmetic sheet according to the present invention may be applied onto the skin of the body and/or the face, and/or the lips of a user . It has been known that C0₂ has effects of accelerating blood flow by the vasodilatation of blood vessels, which contribute to slimming and activating the skin such as increasing skin turnover.

In addition, it is believed that C0₂ in blood will increase free 0₂ due to the Bohr effect (C0₂ encompassed in red blood cells cause with water to produce HC0₃- and H+, so that the pH in the red blood cells is reduced, which results in the low affinity of the hemoglobin in the blood red cells with oxygen) . The free oxygen (0₂) can contribute to inactivate bacteria or the like, and can provide healing or treating effects.

In combination of the above effects, the carbon dioxide in the cosmetic sheet according to the present invention can have

advantageous functions of not only for slimming but also

If the cosmetic sheet according to the present invention

comprises or consists of a substrate comprising at least one gel- forming polysaccharide such as bio-cellulose and/or alginic acid or a salt thereof, and preferably water, it can be especially easily or simply used by being applied onto the skin, preferably the skin of the face, or the lips.

It is possible to apply at least one cosmetic product such as an ointment or a cream onto the skin or the lips, before applying the cosmetic sheet according to the present invention onto the skin or the lips. This will enhance or improve the cosmetic effects such as slimming.

If the aqueous medium in the cosmetic sheet according to the present invention comprises at least one cosmetic ingredient, or if the cosmetic sheet according to the present invention

comprises at least one additional layer comprising at least one cosmetic ingredient, in addition to the substrate, the cosmetic process can be simplified, because a step of applying at least one cosmetic product onto the skin or the lips may be omitted.

Under the cosmetic process according to the present invention, it is possible to leave the cosmetic sheet according to the present invention on the skin or the lips for from 1 minute to 60 minutes, preferably from 10 minutes to 45 minutes, and more preferably from 15 minutes to 30 minutes.

Furthermore, if the cosmetic sheet according to the present invention comprises water, the cosmetic sheet according to the present invention can also ameliorate wrinkles, in particular, not only fine lines but also deep lines such as nasolabial folds, and dryness of the skin or the lips.

The specific nature of the present invention, as well as other objects, uses and advantages thereof, will be clearly apparent from the description and from the accompanying drawing.

EXAMPLES

The present invention will be described in more detail by way of examples, which however should not be construed as limiting the scope of the present invention.

[Preparation of Test Sheets]

A high pressure (0.2 MPa) gas of C0₂ was provided from a C0₂ gas high pressure tank into a pressure bottle including an aqueous solution under agitation to dissolve the C0₂ gas into the aqueous solution. Thus, a cosmetic lotion including dissolved C0₂ was prepared. As a result of gas chromatography analysis, it was found that the concentration of C0₂ in the cosmetic lotion was 1,580 ppm.

Then, each of the following sheets (Example 1 and Comparative Example 1) was immersed in the above cosmetic lotion in order for each sheet to absorb the cosmetic lotion.

Example 1: Bio-cellulose mask sheet (marketed as Lancome

Gefinique Mask by L'Oreal)

Comparative Example 1: Spunlace nonwoven sheet (rayon fiber 45% and pulp fiber 55%) with a basis weight of 80 g/m²

As a result, two test sheets according to Example 1 and

Comparative Example 1 with a cosmetic lotion including C0₂ were prepared.

[Air Permeabilty Test] The air permeability of the above two test sheets was measured in accordance with the Frazier method (JIS L 1096) . The results of the measurements are shown in Table 1.

Table 1

It was found that the test sheet according to Example 1 has lower air permeability so that it can better hold C0₂ as compared to the test sheet according to Comparative Example 1.

[Cosmetic Effect Evaluation]

The test sheet according to Example 1 is applied onto half of the face of a female panelist, while the test sheet according to

Comparative Example 1 is applied onto the other half of the face of the female panelist. Both test sheets are left for 10 minutes. Then, both test sheets are removed from the face.

The blood flow on the face is measured with a laser doppler blood flow rate measurement device (Integral Corporation). It is found that the blood flow on the half of the face to which the test sheet according to Example 1 is applied is higher than that on the other half of the face to which the test sheet according to Comparative Example 1 is applied.

Accordingly, the test sheet according to Example 1 can provide better cosmetic effects derived from C0₂ gas such as slimming and skin turnover than the test sheet according to Comparative

Example 1.

Claims

A cosmetic sheet comprising:

at least one substrate comprising at least one gel-forming material; and

at least one aqueous medium comprising 200 ppm or more, preferably 1,000 ppm or more, and more preferably 1,500 ppm or more, of carbon dioxide which is dissolved in the aqueous medium.

The cosmetic sheet according to Claim 1, wherein the pH of the aqueous medium is 8.0 or less, preferably 7.0 or less, and more preferably 6.0 or less.

The cosmetic sheet according to Claim 1 or 2, wherein the carbon dioxide has been made to dissolve to the aqueous medium by contacting the aqueous medium with the carbon dioxide with a high pressure of from 0.1 to 1 MPa, preferably 0.1 to 0.8 MPa, and more preferably 0.1 to 0.5 MPa.

The cosmetic sheet according to any one of Claims 1 to 3, wherein the substrate is in the form of a gel.

The cosmetic sheet according to any one of Claims 1 to 4, wherein the cosmetic sheet does not comprise any woven or nonwoven fabric.

The cosmetic sheet according to any one of Claims

wherein the gel-forming material is selected from

polysaccharides .

The cosmetic sheet according to Claim 6, wherein the

polysaccharide is alginic acid or a salt thereof.

The cosmetic sheet according to Claim 6, wherein the

polysaccharide is cellulose produced by at least one

microorganism.

The cosmetic sheet according to Claim 8, wherein the

cellulose comprises cellulose microfibrils.

The cosmetic sheet according to Claim 9, wherein each

cellulose microfibril has a diameter of 1 to 100 nm,

preferably 2 to 50 nm, and more preferably 3 to 10 nm. The cosmetic sheet according to Claim 9 or 10, wherein the cellulose microfibrils form a network structure.

The cosmetic sheet according to any one of Claims 1 to 11, wherein the thickness of the substrate is 0.01 mm to 5 mm, preferably 0.05 mm to 3 mm, and more preferably 0.1 mm to 2 mm .

The cosmetic sheet according to any one of Claims 1 to 12, wherein the substrate comprises at least a part of the aqueous medium.

A cosmetic process for the treatment of the skin or the lips, comprising the step of:

applying onto the skin or the lips at least one cosmetic sheet according to any one of Claims 1 to 13.

The process according to Claim 14, wherein the treatment is slimming improving the relief pattern of the skin, making pores on the skin less noticeable, treating acnes and pimples on the skin, making the skin bright and/or white, and/or improving the skin conditions.

A package comprising:

at least one cosmetic sheet according to any one of Claims 1 to 13.