JP7595008B2 - Beauty Methods - Google Patents

Description

The present disclosure relates to a cosmetic method that utilizes moisturizing effects.

In recent years, various beauty methods have been proposed to improve skin problems.

Patent Document 1 discloses a beauty method for preventing acne and cleansing at the same time, which includes the steps of impregnating a sheet with a lotion containing component (A): an anti-inflammatory agent, component (B): a bactericide, component (C): a fatty acid ester nonionic surfactant, component (D): a moisturizer, and component (E): water, and wiping away dirt on the skin with the sheet impregnated with the lotion.

Patent Document 2 discloses a cosmetic method in which an emulsion cosmetic containing 5 to 50% by mass of an oily component is applied onto the skin, and then a skin patch sheet is applied, which has a sheet base layer and an adhesive layer that can adhere to the skin surface, and the water vapor permeability of the entire sheet including the sheet base layer and the adhesive layer is 200 to 2,000 g/ ^m2 ·24 hrs.

JP 2016-132625 A JP 2011-178693 A

For example, in Japan, the humidity in outdoor environments tends to be high during the rainy rainy season, while the humidity tends to be quite low during the dry winter season. In recent years, the use of air conditioners has led to quite low humidity in indoor workplaces and shopping centers. In such low-humidity environments, moisture evaporates from the skin, causing it to lose moisture, which tends to lead to skin problems such as rough skin and wrinkles.

To alleviate such skin troubles, a moisturizer such as glycerin is generally applied to the skin. However, even if the moisturizer component applied to the skin temporarily retains moisture generated by the skin and exerts moisturizing properties, if the humidity of the outside air is low, the retained moisture evaporates into the outside air over time, and therefore sufficient moisturizing effects cannot be obtained. Furthermore, if a person sweats while such a moisturizer is applied to the skin, the occlusion effect of the spread moisturizer makes it difficult for the sweat to evaporate into the outside air, which tends to cause a sticky and uncomfortable feeling.

For example, the sheet described in Patent Document 2 always has a relatively low moisture permeability, and therefore, when a large amount of sweat is produced, the sweat cannot be efficiently evaporated into the outside air, which is likely to cause a sticky and uncomfortable feeling. In addition, such a sheet is in a state where moisture from the skin is constantly evaporated through the sheet, so that such a sheet does not provide a sufficient moisturizing effect in a low humidity environment where moisture from the skin is easily evaporated, and is therefore not likely to be able to fully improve skin problems such as rough skin.

Therefore, the subject of the present disclosure is to provide a beauty method that can ensure moisturizing of the skin while reducing sticky discomfort in a high humidity environment or when sweating, and can also ensure moisturizing of the skin and enhance the beauty effect even in a low humidity environment.

<Aspect 1>
A cosmetic method in which a moisturizing polyvinyl alcohol film is applied to the body surface.
<Aspect 2>
2. The cosmetic method according to claim 1, wherein the application of the moisturizing polyvinyl alcohol film to a body surface is carried out by sticking it in the form of a self-supporting film.
Aspect 3
A cosmetic method according to Aspect 1, wherein the application of the moisturizing polyvinyl alcohol film to a body surface is carried out by spreading a composition containing polyvinyl alcohol and water on the body surface.
<Aspect 4>
The cosmetic method according to any one of Aspects 1 to 3, wherein the moisture-retaining polyvinyl alcohol film is applied to the body surface after a waterproof and moisture-permeable layer is applied to the body surface.
<Aspect 5>
The cosmetic method according to aspect 4, wherein the waterproof/moisture-permeable layer is applied to a body surface by sticking it in the form of a self-supporting film.
Aspect 6
The cosmetic method according to aspect 4, wherein the application of the waterproof and moisture-permeable layer to a body surface is carried out by applying a waterproof and moisture-permeable layer component to a body surface.
Aspect 7
The cosmetic method according to aspect 1 or 2, wherein a waterproof and moisture-permeable layer is applied to one side of the polyvinyl alcohol film for moisturizing, and then the polyvinyl alcohol film for moisturizing is applied to a body surface via the waterproof and moisture-permeable layer.
<Aspect 8>
Aspect 8. The cosmetic method according to any one of aspects 1 to 7, wherein the thickness of the moisturizing polyvinyl alcohol film is 100 μm or less.
<Aspect 9>
The cosmetic method according to any one of Aspects 1 to 8, wherein the moisturizing polyvinyl alcohol film contains unmodified polyvinyl alcohol.
Aspect 10
The cosmetic method according to any one of aspects 4 to 9, wherein the waterproof and moisture-permeable layer is at least one selected from an oil layer containing at least one of petrolatum and liquid paraffin, a polylactic acid layer, and an artificial skin.
<Aspect 11>
The cosmetic method according to any one of aspects 1 to 10, wherein, when the moisture-retaining polyvinyl alcohol film or a laminate including the moisture-retaining polyvinyl alcohol film and the waterproof/moisture-permeable layer is evaluated in a moisture evaporation test, the amount of moisture evaporation measured in an environment of 23° C. and 40% RH is less than the amount of moisture evaporation measured in an environment of 28° C. and 70% RH.

According to the present disclosure, it is possible to provide a beauty method that can ensure moisturizing of the skin while reducing sticky discomfort in a high humidity environment or when sweating, and can also ensure moisturizing of the skin and enhance the beauty effect even in a low humidity environment.

1 is a schematic diagram showing the moisture blocking state when the moisture-retaining polyvinyl alcohol film of the present disclosure is applied to the skin in a low humidity environment. FIG. 1 is a schematic diagram showing the moisture permeation state when the moisture-retaining polyvinyl alcohol film of the present disclosure is applied to the skin in a high humidity environment. 1 is a schematic diagram showing the moisture permeation state when a thin moisturizing polyvinyl alcohol film of the present disclosure is applied to skin with a relatively high moisture content in a low humidity environment. 1 is a schematic diagram showing the moisture blocking state when a waterproof/moisture permeable layer and a thin moisturizing polyvinyl alcohol film of the present disclosure are applied to skin with a relatively high moisture content in a low humidity environment. FIG. 2 is a schematic diagram of a measurement sample sealed with a polyvinyl alcohol film used in a moisture evaporation test. 1 is a graph showing the amount of water evaporation from each sample in a water evaporation test under an environment of 28° C. and 70% RH (high humidity environment) and 23° C. and 40% RH (low humidity environment).

The following describes in detail the embodiments of the present disclosure. The present disclosure is not limited to the following embodiments, and can be modified in various ways within the scope of the present invention.

The cosmetic method disclosed herein involves applying a moisturizing polyvinyl alcohol film to the body surface.

Although not limited by the principle, the cosmetic method of the present disclosure is believed to be able to ensure moisturizing of the skin while reducing sticky discomfort in a high humidity environment or when sweating, and is also able to ensure moisturizing of the skin and enhance the cosmetic effect even in a low humidity environment, based on the following principle. Note that in this disclosure, polyvinyl alcohol may be abbreviated as "PVA."

When exposed to dryness, skin can unknowingly lose moisture, leading to a state in which the stratum corneum on the skin's surface is unable to maintain its moisture level. When the skin lacks moisture, it is unable to properly produce the moisturizing ingredients (natural moisturizing factors (NMFs)) that it produces itself. As a result, the barrier and moisturizing functions of the skin's surface are reduced, making the skin more susceptible to damage, which is thought to cause the skin to lose moisture and develop rough skin.

In addition, if the stratum corneum on the skin's surface continues to lack moisture, the body tries to quickly create new cells to repair the damaged stratum corneum, which speeds up the skin's regeneration (turnover) process and simultaneously leads to the rapid production of immature, incomplete cells. As a result, the skin is not fully prepared to produce a normal stratum corneum, and the skin surface cannot retain enough moisture, resulting in a vicious cycle of persistent rough skin.

It is generally known that PVA has excellent affinity with moisture. For example, as shown in FIG. 1, when a PVA film 101 is applied to the skin, moisture 105 evaporated from the skin binds to PVA molecules 103 in the film, and the PVA molecules 103 move so as to attract each other around the moisture 105, forming gaps 107 through which moisture can pass. However, when the humidity of the external environment is low, the PVA molecules 103 do not move near the outermost surface of the PVA film 101, so it is thought that gaps 107 through which moisture can pass are not formed. As a result, in a low-humidity environment, moisture evaporated from the skin remains below the outermost surface of the PVA film and is not evaporated into the atmosphere, so that it is believed that the skin can be sufficiently moisturized even in a low-humidity environment. This improves the function of producing moisturizing ingredients produced by the skin itself, and also improves the turnover disorder in the stratum corneum, making it less likely for skin troubles such as rough skin to occur, thereby enhancing the beauty effect.

On the other hand, in a high humidity environment or when a large amount of sweat has been released, for example, as shown in Figure 2, the PVA molecules 203 near the outermost surface of the PVA film 201 also move around the moisture 205, so that gaps 207 that allow moisture to pass through are thought to be formed throughout the entire thickness of the film. As a result, under such circumstances, it is believed that excess moisture such as sweat can be evaporated from the skin, reducing the sticky discomfort. Furthermore, in a high humidity environment and when the skin is dry, it is thought that moisture from the environment can be provided to the skin through the PVA film 201.

As shown in FIG. 3, for example, when the PVA film 301 is thin and the skin has a high moisture content, gaps 307 that allow moisture to pass through may be formed even in a low humidity environment, and moisture from the skin may evaporate. In such a case, as shown in FIG. 4, the formation of gaps 407 that allow moisture to pass through can be suppressed by applying a waterproof and moisture-permeable layer 409 between the PVA film 401 and the skin. Although the waterproof and moisture-permeable layer 409 has moisture permeability, it suppresses the movement of moisture from the exposed skin. Therefore, moisture 408 that passes through the waterproof and moisture-permeable layer 409 penetrates the PVA film 401 at a lower rate than when the waterproof and moisture-permeable layer 409 does not exist, so even in the above case, gaps 407 that allow moisture to pass through due to the movement of PVA molecules 403 are not formed near the outermost surface of the PVA film 401, and it is believed that the skin can be moisturized and the beauty effect can be enhanced.

The definitions of terms used in this disclosure are as follows:

In this disclosure, "humidity responsiveness" refers to the ability of the amount of water evaporation to change in response to changes in the humidity environment, specifically, the ability of the amount of water evaporation in a low humidity environment to be less than the amount of water evaporation in a high humidity environment.

In this disclosure, a "low humidity environment" refers to an environment in which the relative humidity at atmospheric pressure and 23°C is 50% RH or less, 45% RH or less, 40% RH or less, 35% RH or less, or 30% RH or less. There is no particular restriction on the lower limit of such relative humidity, but it can be, for example, 3% RH or more, 5% RH or more, 7% RH or more, or 10% RH or more. In addition, such relative humidity can be converted into, for example, weight absolute humidity that is not affected by temperature, and the weight absolute humidity can be 8.7 g/kg or less, 7.9 g/kg or less, 7.0 g/kg or less, 6.1 g/kg or less, or 5.2 g/kg or less, or 0.52 g/kg or more, 0.86 g/kg or more, 1.2 g/kg or more, or 1.7 g/kg or more.

In this disclosure, a "high humidity environment" refers to an environment in which the relative humidity at atmospheric pressure and 28°C is 50% RH or more, 55% RH or more, 60% RH or more, 65% RH or more, 70% RH or more, or 75% RH or more. There is no particular limit to the upper limit of the relative humidity, but it can be, for example, 100% RH or less or less than 100% RH. In addition, the relative humidity can be converted into, for example, weight absolute humidity that is not affected by temperature, and the weight absolute humidity can be 12 g/kg or more, 13 g/kg or more, 14 g/kg or more, 15 g/kg or more, 17 g/kg or more, or 18 g/kg or more, and can be 24 g/kg or less or less than 24 g/kg.

In this disclosure, "film" includes not only films that can be carried alone, such as wrap film, but also thin films that cannot be carried alone, such as coating films. Here, in this disclosure, a distinction is sometimes made between films that can be carried alone, such as wrap film, and thin films that cannot be carried alone, referred to as "non-self-supporting films."

In this disclosure, "beauty" or "beauty method" means applying the moisturizing polyvinyl alcohol film of the present disclosure to the body surface to beautify and smooth the condition of the body surface, or a method of beautifying and smoothing the condition of the body surface, and is different from methods of surgery, treatment, or diagnosis of humans.

In this disclosure, "body surface" means the skin surface of the body.

<Moisturizing polyvinyl alcohol film>
The moisturizing polyvinyl alcohol film (sometimes simply referred to as a "polyvinyl alcohol film" or "PVA film") used in the cosmetic method of the present disclosure is a film having humidity responsiveness. Such humidity responsiveness can be evaluated by the amount of moisture evaporation calculated by a moisture evaporation test. Here, the amount of moisture evaporation is sometimes called the moisture evaporation rate. In addition, since the moisturizing polyvinyl alcohol film can exert a cosmetic effect, a composition including such a moisturizing polyvinyl alcohol film may be called a "moisturizing film cosmetic" or simply a "cosmetic".

Evaluation Method 1
As shown in FIG. 5 , the amount of water evaporation can be calculated by covering the open part of a vial containing 20 mL of water with a measurement sample such as a PVA film, leaving the vial to stand in a low humidity environment, for example, at 23° C. and 40% RH, until the amount of evaporation reaches an equilibrium state where the amount of evaporation is approximately constant over time, and then measuring the amount of water loss.

The polyvinyl alcohol film of the present disclosure, when evaluated in a moisture evaporation test using the amount of moisture evaporation, can exhibit humidity responsiveness such that, for example, the amount of moisture evaporation measured in a low humidity environment of 23°C and 40% RH is less than the amount of moisture evaporation measured in a high humidity environment of 28°C and 70% RH. In contrast, in an open system or a vial container capped with filter paper, the amount of moisture evaporation measured in a low humidity environment of 23°C and 40% RH is greater than the amount of moisture evaporation measured in a high humidity environment of 28°C and 70% RH.

Specifically, in the polyvinyl alcohol film of the present disclosure, the water evaporation rate when measured in a low humidity environment of 23°C and 40% RH can be less than the water evaporation rate when measured in a high humidity environment of 28°C and 70% RH by at least 0.20 mg/ ^cm2 /h, at least 0.25 mg/ ^cm2 /h, at least 0.30 mg/ ^cm2 /h, at least 0.40 mg/ ^cm2 /h, at least 0.45 mg/ ^cm2 /h, or at least 0.50 mg/ ^cm2 /h, and the upper limit can be 1.3 mg/ ^cm2 /h or less, 1.2 mg/ ^cm2 /h or less, 1.0 mg/ ^cm2 /h or less, or 0.95 mg/ ^cm2 /h or less.

In addition, when the measurement environment has a lower humidity than an environment of, for example, 23°C and 40% RH, the polyvinyl alcohol film of the present disclosure can further suppress evaporation of moisture. Therefore, the difference in the amount of evaporated moisture and the evaporation rate described below tends to increase as the difference in the humidity environment of the measurement environment increases.

Evaluation Method 2
Humidity responsiveness can also be evaluated using the water evaporation rate (%) calculated as follows. First, an open vial containing 20 mL of water is left to stand in a low humidity environment of, for example, 23°C and 40% RH until the amount of evaporation is approximately constant over time and reaches equilibrium, and then the amount of water lost is measured, and the amount of water evaporation 1, which is the amount of water lost per unit area and unit time, is calculated. Next, as shown in FIG. 5, the open part of another vial containing 20 mL of water is covered with a measurement sample such as a PVA film, and left to stand in the same environment until it reaches equilibrium, and then the amount of water lost is measured, and the amount of water evaporation 2, which is the amount of water lost per unit area and unit time, is calculated. Then, the ratio of the amount of water evaporation 2 to the amount of water evaporation 1 is calculated as a percentage to calculate the water evaporation rate.

The polyvinyl alcohol film of the present disclosure, when evaluated in a moisture evaporation test using a moisture evaporation rate, can exhibit humidity responsiveness such that, for example, the moisture evaporation rate measured in a low humidity environment of 23°C and 40% RH is less than the moisture evaporation rate measured in a high humidity environment of 28°C and 70% RH. In contrast, in an open system or a vial with a filter paper lid, the amount of moisture evaporation measured in a low humidity environment of 23°C and 40% RH is greater than the amount of moisture evaporation measured in a high humidity environment of 28°C and 70% RH.

Specifically, in the polyvinyl alcohol film of the present disclosure, the moisture evaporation rate when measured in a low humidity environment of 23°C and 40% RH can be 2.0% or more, 2.5% or more, 3.0% or more, 3.5% or more, or 4.0% or more less than the moisture evaporation rate when measured in a high humidity environment of 28°C and 70% RH, and the upper limit can be 10% or less, 9.5% or less, 9.0% or less, or 8.5% or less.

From the viewpoint of reducing or suppressing evaporation of moisture in a low humidity environment, the polyvinyl alcohol film is preferably a film in which openings are not always formed over the entire surface, rather than a film in which openings are always formed over the entire surface to provide moisture permeability, such as a nonwoven fabric or a film with physically provided through-holes. However, the polyvinyl alcohol film of the present disclosure may have through-holes partially formed in the film, for example, in order to improve air retention when the film is applied, so long as it can exhibit the above-mentioned humidity responsiveness.

<material>
The material constituting the polyvinyl alcohol film of the present disclosure is not particularly limited as long as the resulting film exhibits humidity responsiveness, and polyvinyl alcohol or its derivatives can be used alone or in combination of two or more. Examples of polyvinyl alcohol derivatives include modified polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, etc. In addition, from the viewpoint of humidity responsiveness, it is preferable that such a film is composed of unmodified polyvinyl alcohol and/or modified polyvinyl alcohol.

Polyvinyl alcohol can be prepared using, for example, fully saponified polyvinyl alcohol with a saponification degree of 99% or more, partially saponified polyvinyl alcohol with a saponification degree of 90% or more but less than 99%, and partially saponified polyvinyl alcohol with a saponification degree of 70% or more but less than 90%. These polyvinyl alcohols can be used alone or in combination of two or more. Among them, fully saponified polyvinyl alcohol and partially saponified polyvinyl alcohol are preferred, and fully saponified polyvinyl alcohol is more preferred, from the viewpoint of humidity responsiveness, particularly the effect of suppressing water evaporation in a low humidity environment. Examples of the modification treatment of polyvinyl alcohol include diol modification, anion modification, and cation modification.

From the viewpoint of humidity responsiveness, particularly the effect of suppressing water evaporation in a low humidity environment, unmodified polyvinyl alcohol or diol-modified polyvinyl alcohol is preferred, with unmodified polyvinyl alcohol being more preferred.

Such polyvinyl alcohol can be commercially available. Examples of unmodified fully saponified polyvinyl alcohol include Gohsenol (trademark) NL-05 (manufactured by Mitsubishi Chemical Corporation), KURARAY POVAL (trademark) PVA-117H (manufactured by Kuraray Co., Ltd.), and KURARAY POVAL (trademark) PVA-124 (manufactured by Kuraray Co., Ltd.). Examples of anion-modified fully saponified polyvinyl alcohol include Gohsenex (trademark) T-330H (manufactured by Mitsubishi Chemical Corporation). Examples of diol-modified fully saponified polyvinyl alcohol include Nichigo G Polymer (trademark) OKS-1089 and Nichigo G Polymer (trademark) OKS-1109 (both manufactured by Mitsubishi Chemical Corporation).

An example of an unmodified partially saponified polyvinyl alcohol is KURARAY POVAL (trademark) PVA-617 (manufactured by Kuraray Co., Ltd.), and an example of a diol-modified partially saponified polyvinyl alcohol is Nichigo G Polymer (trademark) OKS-8096 (manufactured by Mitsubishi Chemical Corporation).

Examples of unmodified partially saponified polyvinyl alcohol include GOHSENOL (trademark) GM-14, GOHSENOL (trademark) PVA EG-05, GOHSENOL (trademark) PVA EG-40 (all manufactured by Mitsubishi Chemical Corporation), and KURARAY POVAL (trademark) PVA-235 (manufactured by Kuraray Co., Ltd.), and examples of cation-modified partially saponified polyvinyl alcohol include GOHSENOL (trademark) PVA K-434 (manufactured by Mitsubishi Chemical Corporation).

<Thickness>
The thickness of the polyvinyl alcohol film is not particularly limited, and can be appropriately adjusted depending on the part to which the polyvinyl alcohol film is applied, the purpose of use, the amount of sweat glands or the amount of moisture evaporation from the skin of the user, or the balance of humidity responsiveness when combined with a waterproof and moisture-permeable layer described below, etc. For example, the thickness of the polyvinyl alcohol film can be 100 μm or less, 70 μm or less, 50 μm or less, 20 μm or less, 15 μm or less, 13 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, or 0.5 μm or less, and can be 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more. In particular, when used in combination with a waterproof and moisture-permeable layer described later, the thickness of the polyvinyl alcohol film can be as thin as 15 μm or less, 13 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 0.7 μm or less, or 0.5 μm or less, and can be 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more.

When the polyvinyl alcohol film is a free-standing film, the thickness of the polyvinyl alcohol film can be defined as the average value calculated by measuring the thickness of any part of the film at least five times using a high-precision digital micrometer (MDH-25MB, manufactured by Mitutoyo Corporation). When the thickness of the polyvinyl alcohol film is too thin to be measured with a high-precision digital micrometer, the thickness of the polyvinyl alcohol film can be determined by a similar method using a scanning electron microscope as described below.

For example, when the polyvinyl alcohol film is combined with a waterproof/moisture-permeable layer (described later) to form a laminate, and the waterproof/moisture-permeable layer cannot be separated from the laminate, a scanning electron microscope is used to measure the thickness direction cross section of the laminate. The average thickness of at least five arbitrary points on the polyvinyl alcohol film in the laminate can then be defined as the thickness of the polyvinyl alcohol film.

<Basance>
Polyvinyl alcohol films can also be specified by basis weight instead of thickness. Here, basis weight in the present disclosure can be defined as weight (mg) per 1 ^cm2 of film. The basis weight of the polyvinyl alcohol film can be, for example, 0.0010 mg/ ^cm2 or more, 0.0060 mg/cm2 or ^more , 0.010 mg/cm2 or ^more , 0.025 mg/cm2 or ^more , 0.035 mg/ ^cm2 or more, 0.050 mg/ ^cm2 or more, 0.070 mg/ ^cm2 or more, 0.10 mg/ ^cm2 or more, 0.15 mg/ ^cm2 or more, 0.30 mg/cm2 or ^more , or 0.45 mg/ ^cm2 or more, and can be 12.0 mg/cm2 or ^less , 8.5 mg/cm2 or ^less , 6.0 mg/cm2 or ^less , 4.5 mg/cm2 or ^less , 2.5 mg/cm2 or ^less , 2.0 mg/cm2 or ^less , 1.5 mg/cm2 or ^less , 1.2 mg/cm2 or ^less , 1.0 mg/cm2 or ^less , 0.80 mg/cm2 or less. ² or less, 0.60 mg/cm2 or ^less , 0.35 mg/cm2 or ^less , 0.15 mg/cm2 or ^less , 0.10 mg/cm2 or ^less , 0.085 mg/cm2 or ^less , or 0.060 mg/cm2 or ^less .

<Optional ingredients>
Various components can be appropriately blended into the polyvinyl alcohol film of the present disclosure as long as they do not affect the effects of the present invention. Examples of the various components include moisturizers, polymers (e.g., carboxyvinyl polymers, (N,N-dimethylacrylamide-2-acrylamidodimethylpropanesulfonic acid) crosslinked copolymers, copolymers of 2-methacryloyloxyphosphorylcholine (MPC) and n-butyl methacrylate (BMA), rubbers, elastomers, pressure sensitive adhesives, adhesives, adhesion modifiers, adhesion modifiers, UV absorbers, antioxidants, preservatives, antioxidant assistants, crosslinking agents, light diffusing agents, fillers, skin nutrients, vitamins, pharmaceuticals, quasi-drugs, various drugs applicable to cosmetics, etc., organic powders, pigments, dyes, colorings, and fragrances. These optional components can be used alone or in combination of two or more. Here, glycerin, which is a moisturizer, may increase moisture permeability in a low humidity environment, so that moisturizers other than glycerin, such as dipropylene glycol, POE(14)POP(7)dimethyl ether, etc. are preferred. Here, POE means polyoxyethylene, and POP means polyoxypropylene.

Waterproof and breathable layer
The waterproof/moisture-permeable layer used in the cosmetic method of the present disclosure is a layer that has waterproof properties and moisture permeability, and does not exhibit humidity responsiveness by itself.

As shown in Figure 3, for example, if the polyvinyl alcohol film 301 is thin and the skin has a high moisture content, gaps 307 that allow moisture to pass through may be formed even in a low humidity environment, causing moisture to evaporate from the skin. In such a case, as shown in Figure 4, by applying a waterproof and moisture-permeable layer 409 between the polyvinyl alcohol film 401 and the skin, the formation of gaps 407 that allow moisture to pass through can be suppressed and moisture retention can be ensured.

Furthermore, as the polyvinyl alcohol film becomes thicker, its rigidity increases, which may make it difficult to apply to the skin and may also make it look unattractive. Even if the waterproof/moisture-permeable layer is relatively thin, when combined with the polyvinyl alcohol film, the laminate containing them can provide sufficient humidity responsiveness similar to the humidity responsiveness performance of the polyvinyl alcohol film described above, and therefore the overall thickness can be reduced. As a result, the laminate having such a configuration can improve the applicability to the skin and the appearance compared to when a thick polyvinyl alcohol film is used.

The surface of the polyvinyl alcohol film opposite the body surface side is used to adjust the moisture permeability to the external environment, so it is preferable that no waterproof moisture permeable layer or any additional layer is formed on this surface. Therefore, when a waterproof moisture permeable layer is applied to the polyvinyl alcohol film in advance for use, it is preferable that the waterproof moisture permeable layer is configured to be positioned closer to the body surface than the polyvinyl alcohol film.

The waterproof and moisture-permeable layer may be a single layer or a laminate. The waterproof and moisture-permeable layer may be in the form of a free-standing film or a non-free-standing film. The waterproof and moisture-permeable layer may be configured to be applied to the entire surface or a part of the polyvinyl alcohol film.

<material>
The waterproof and moisture-permeable layer is not particularly limited as long as it is a layer that can exhibit the above-mentioned humidity responsiveness when combined with the polyvinyl alcohol film. Examples of the waterproof and moisture-permeable layer include at least one selected from an oil layer, a polylactic acid layer, and an artificial skin.

Examples of materials for the oil layer include polar oils such as ester oils and non-polar oils such as hydrocarbon oils. Among these, non-polar oils are preferred from the viewpoint of humidity responsiveness.

Examples of non-polar oils include petrolatum, liquid paraffin, tetraisobutane, hydrogenated polydecene, olefin oligomer, isododecane, isohexadecane, squalane, polybutene, hydrogenated polybutene, polyisobutene, hydrogenated polyisobutene, etc. These can be used alone or in combination of two or more. Among them, petrolatum and liquid paraffin are preferred from the viewpoint of humidity responsiveness.

Materials that can be used to make the artificial skin include, for example, rubber or elastomers such as urethane rubber, olefin rubber, silicone rubber, acrylic rubber, and natural rubber, or α-gel. These can be used alone or in combination of two or more. Among these, silicone rubber is preferred from the standpoint of flexibility, humidity responsiveness, etc.

<Thickness>
The thickness of the waterproof and moisture-permeable layer is not particularly limited, and can be appropriately adjusted depending on the area to which the waterproof and moisture-permeable layer is applied, the purpose of use, the amount of sweat glands or the amount of moisture evaporated from the skin of the user, the balance of humidity responsiveness when combined with the above-mentioned polyvinyl alcohol film, and the like.

<Basance>
The waterproof/moisture-permeable layer can also be defined by, for example, its basis weight. The basis weight of the waterproof/moisture-permeable layer can be, for example, 1.0 mg/cm2 or ^more , 1.2 mg/cm2 or ^more , or 1.4 mg/cm2 ^or more, and can be 2.0 mg/cm2 or ^less , 1.8 mg/cm2 or ^less , or 1.6 mg/cm2 or ^less .

<Optional ingredients>
The waterproof and moisture-permeable layer of the present disclosure may be appropriately blended with various components within a range that does not affect the effects of the present invention. Examples of the various components include moisturizers, polymers, rubbers, elastomers, pressure-sensitive adhesives, adhesives, adhesion modifiers, adhesion modifiers, UV absorbers, antioxidants, preservatives, antioxidant assistants, light diffusing agents, fillers, skin nutrients, vitamins, various drugs applicable to medicines, quasi-drugs, cosmetics, etc., organic powders, pigments, dyes, colorants, and fragrances. These optional components may be used alone or in combination of two or more.

《Optional composition layer》
The moisture-retaining polyvinyl alcohol film of the present disclosure can be used in combination with any constituent layer within a range that does not affect the effects of the present invention. Examples of such constituent layers include a moisture-permeable adhesive layer (e.g., an adhesive layer having through holes), a protective film having peeling properties, and a release sheet, which can be used alone or in combination of two or more. For example, a protective film can be applied to one side of the polyvinyl alcohol film, and/or a release sheet can be applied to the opposite side. Here, the surface of the protective film and the release sheet may be subjected to a release treatment such as silicone. In addition, the release performance of the protective film and the release sheet against the polyvinyl alcohol film may be the same or different. From the viewpoint of ease of peeling from the polyvinyl alcohol film, it is preferable that these release performances are different.

The material of the optional constituent layer is not particularly limited, but from the viewpoint of ease of handling, examples of the material include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, cotton, paper, etc. The optional constituent layer may be in the form of a film, or in the form of a nonwoven fabric, knitted fabric, or woven fabric.

<<Beauty treatment using moisturizing polyvinyl alcohol film>>
The cosmetic method of the present disclosure is carried out by applying a moisturizing polyvinyl alcohol film to the body surface. The moisturizing polyvinyl alcohol film applied to the skin can reduce or inhibit evaporation of moisture from the skin in a low humidity environment, and can sufficiently moisturize the skin even in a low humidity environment. As a result, the function of producing moisturizing components produced by the skin itself is improved, and the turnover disorder in the stratum corneum is also improved, so that skin troubles such as rough skin are less likely to occur, and the cosmetic effect can be improved.

There are no particular limitations on the means of applying the polyvinyl alcohol film to the body surface; for example, it may be attached to the body surface in the form of a free-standing film, or it may be applied by applying the composition for making a polyvinyl alcohol film, described below, to the body surface.

As a means for attaching the polyvinyl alcohol film to the body surface in the form of a self-supporting film, for example, if the polyvinyl alcohol film has a moisture-permeable adhesive layer, it can be attached to the body surface via the adhesive layer. Alternatively, since the polyvinyl alcohol film becomes adhesive when it comes into contact with water, the film can be attached to the body surface part to which the film is to be applied after applying water or lotion, or the polyvinyl alcohol film can be applied to the body surface after spreading water or lotion.

The composition for producing a polyvinyl alcohol film may be applied to the body surface, for example, by spraying the composition from a spray container so as to form a film, or by pouring the composition into a container without a spray function, taking an appropriate amount of the composition from the container onto a finger or the like, and spreading it over the body surface.

The application of the polyvinyl alcohol film to the body surface may be carried out after the application of the waterproof and moisture-permeable layer to the body surface. In this case, the application of the waterproof and moisture-permeable layer to the body surface may be carried out, for example, by attaching it in the form of a free-standing film, or by applying the waterproof and moisture-permeable layer components to the body surface. Here, the application of the polyvinyl alcohol film to the waterproof and moisture-permeable layer may be carried out in the same manner as the means for applying the polyvinyl alcohol film to the body surface, or, if the waterproof and moisture-permeable layer itself has adhesiveness, the polyvinyl alcohol film may be attached by utilizing that adhesiveness.

As a means for attaching the waterproof/moisture permeable layer to the body surface in the form of a free-standing film, for example, if the waterproof/moisture permeable layer itself has adhesiveness, the waterproof/moisture permeable layer in such a form can be attached to the body surface as is. If the waterproof/moisture permeable layer itself does not have adhesiveness, the waterproof/moisture permeable layer in such a form can be attached to the body surface via, for example, an adhesive layer having moisture permeability or another waterproof/moisture permeable layer having adhesiveness.

The waterproof/moisture-permeable layer components can be applied to the body surface by preparing a composition containing the various components that make up the waterproof/moisture-permeable layer and applying it in the same manner as the composition for making the polyvinyl alcohol film described above.

The application of the polyvinyl alcohol film to the body surface may be performed by applying a waterproof and moisture-permeable layer to one side of the polyvinyl alcohol film, and then applying the polyvinyl alcohol film to the body surface via this waterproof and moisture-permeable layer. Here, when the waterproof and moisture-permeable layer itself has adhesiveness, the waterproof and moisture-permeable layer can be applied to the polyvinyl alcohol film by utilizing its adhesiveness. Also, when the waterproof and moisture-permeable layer does not have adhesiveness, the waterproof and moisture-permeable layer can be applied to the polyvinyl alcohol film via a moisture-permeable adhesive layer or another waterproof and moisture-permeable layer having adhesiveness. In this case, a moisture-permeable adhesive layer or another waterproof and moisture-permeable layer having adhesiveness can be applied to the body surface of the waterproof and moisture-permeable layer, or a moisture-permeable adhesive layer or another waterproof and moisture-permeable layer having adhesiveness can be applied to the body surface, thereby applying a polyvinyl alcohol film having a non-adhesive waterproof and moisture-permeable layer.

<Areas to which the moisturizing polyvinyl alcohol film should be applied>
The polyvinyl alcohol film for moisturizing can be applied to any part of the skin surface of the body, that is, any part of the body surface. For example, it can be applied appropriately to the skin surface of the face (lips, eyes, nose, cheeks, forehead, etc.), neck, ears, hands, arms, legs, feet, chest, abdomen, back, etc. Here, the skin also includes nails that have hardened due to changes in the keratin of the epidermis of the skin.

<<Method for producing a moisture-retaining polyvinyl alcohol film>>
The moisturizing polyvinyl alcohol film of the present disclosure can be produced, for example, by using a commercially available polyvinyl alcohol film of a predetermined thickness, or by using a composition for producing a polyvinyl alcohol film.

In a manufacturing method using a composition for producing a polyvinyl alcohol film, for example, the composition is applied onto a release sheet by any means, for example, by known coating means such as offset printing, gravure coating, bar coating, knife coating, spray coating, etc., and the film can be continuously prepared by optionally applying, for example, a drying process, a crosslinking process, a process for applying a waterproof/moisture-permeable layer, a process for laminating constituent layers such as a protective film, a winding process, etc.

The moisturizing polyvinyl alcohol film of the present disclosure can also be prepared discontinuously using a composition for preparing a polyvinyl alcohol film. For example, a predetermined amount of such a composition may be added to a container or a mold, and dried to prepare a polyvinyl alcohol film. At this time, for example, a waterproof and moisture-permeable layer, a protective film, a release sheet, etc. may be applied to the obtained polyvinyl alcohol film as necessary. Alternatively, the composition may be poured into, for example, a tube container or a spray container, and the composition may be applied from such a container to a body surface, or the composition may be applied to a waterproof and moisture-permeable layer previously applied to the body surface and dried to directly form a polyvinyl alcohol film on the body surface.

The size and shape of the moisturizing polyvinyl alcohol film or the laminate containing the film can be adjusted appropriately using known cutting methods such as half cutting and laser cutting depending on the area to which it is applied.

<Polyvinyl alcohol film-forming composition>
The polyvinyl alcohol film for moisture retention of the present disclosure can be prepared using a composition for preparing a polyvinyl alcohol film. Such a composition can be prepared by appropriately mixing the above-mentioned polyvinyl alcohol, water, and the following optional components.

(Optional ingredients)
The composition for preparing the polyvinyl alcohol film of the present disclosure can be appropriately blended with various components within a range that does not affect the effects of the present invention. Examples of various components include lower alcohols, polyhydric alcohols, higher alcohols, oils, various extracts, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, moisturizing agents, polymers, rubbers, elastomers, pressure sensitive adhesives, adhesives, adhesion modifiers, adhesion modifiers, UV absorbers, antioxidants, preservatives, antioxidant assistants, crosslinking agents, light diffusing agents, fillers, gelling agents (thickening agents), skin nutrients, vitamins, various drugs applicable to medicines, quasi-drugs, cosmetics, etc., organic powders, pigments, dyes, colorants, and fragrances. These optional components can be used alone or in combination of two or more.

Cosmetic kit
The moisturizing polyvinyl alcohol film of the present disclosure can be provided in the form of a cosmetic kit including a polyvinyl alcohol film or a composition for producing the polyvinyl alcohol film.

<Optional parts>
The cosmetic kit may further include optional components. Examples of such optional components include the above-mentioned components to which the waterproof/moisture-permeable layer can be applied, a cutter, scissors, a mirror, etc. These optional components may be provided in the cosmetic kit alone or in combination of two or more.

The present invention is described in more detail below with reference to examples, but is not limited to these.

Examples 1 to 3 and Comparative Examples 1 to 2
The polyvinyl alcohol (PVA) films obtained by the manufacturing methods described in Examples 1 to 3, as well as the filter paper (Comparative Example 1) and polylactic acid film (Comparative Example 2) used for comparison, were evaluated for humidity responsiveness by the moisture evaporation test shown below. The results are shown in Table 1 and Figure 6. As a reference example, the results of the open system sample are shown in Table 1.

<Water Evaporation Test>
The circular opening (radius: 0.7 cm, area: 1.54 ^cm2 ) of a vial containing 20 mL of water was covered with each measurement sample, and the vial was placed in a thermostatic chamber under predetermined temperature and humidity conditions. After leaving the vial for about 2 to 3 days until the amount of evaporation reached an equilibrium state where the amount of evaporation was almost constant over time, the amount of water lost in the vial was measured, and the amount of water evaporation, which is the amount of water lost per unit area and unit time, was calculated. Here, the test was performed in two environments: a low humidity environment of 23°C and 40% RH, and a high humidity environment of 28°C and 70% RH.

Example 1
A composition for producing a polyvinyl alcohol film was prepared by mixing unmodified fully saponified polyvinyl alcohol, KURARAY POVAL (trademark) PVA-117H (manufactured by Kuraray Co., Ltd.), which is ion-exchanged water, in a 10 mL vial and stirring the mixture so that the polyvinyl alcohol concentration was 5.0% by mass. Next, 3.0 g of the resulting 5.0% by mass aqueous solution composition was added to a roughly circular petri dish having an area of 19.6 ^cm2 and dried to prepare a polyvinyl alcohol film having a thickness of about 60 μm and a basis weight of about 7.6 mg/ ^cm2 as a measurement sample.

Example 2
A polyvinyl alcohol film as a measurement sample was prepared in the same manner as in Example 1, except that the concentration of polyvinyl alcohol was changed to 1.0 mass %. The thickness of the obtained film was about 10 μm, and the basis weight was about 1.5 mg/ ^cm2 .

Example 3
Except for changing the concentration of polyvinyl alcohol to 0.5% by mass, a polyvinyl alcohol film as a measurement sample was prepared in the same manner as in Example 1. The thickness of the obtained film was about 6 μm, and the basis weight was about 0.76 mg/ ^cm2 .

Comparative Example 1
Filter paper #133 manufactured by ADVANTEC Co., Ltd., having a thickness of 250 μm and a basis weight of 14 mg/cm ² , was used as a measurement sample for Comparative Example 1.

Comparative Example 2
A polylactic acid film having a thickness of about 200 nm and a basis weight of about 0.025 mg/ ^cm2 was prepared by spin coating using a 0.1% by mass polylactic acid solution prepared using tetrahydrofuran. Two of these polylactic acid films were stacked together and used as the measurement sample for Comparative Example 2.

Reference Example 1
As a reference example, an open sample was used in which the open part of the vial was not capped.

<result>
As is clear from Table 1 and Figure 6, in the case of the filter paper of Comparative Example 1 and the polylactic acid film of Comparative Example 2, the amount of water evaporated in a low humidity environment was greater than that in a high humidity environment, and humidity responsiveness was not demonstrated. On the other hand, in the case of the polyvinyl alcohol films of Examples 1 to 3, the amount of water evaporated in a low humidity environment was clearly lower than the amount of water evaporated in a high humidity environment, and it was confirmed that they exhibit humidity responsiveness.

Examples 4 and 5 and Comparative Example 3
The amount of water evaporation from human skin was evaluated, and the results are summarized in Table 2. Here, the amount of water evaporation was measured using a VAPO METER manufactured by Keystone Corporation in two environments: a low humidity environment of 23° C. and 40% RH, and a high humidity environment of 28° C. and 70% RH.

Example 4
The polyvinyl alcohol film (thickness: about 10 μm) obtained in Example 2 was attached to the skin surface on the inside of a human left arm.

Example 5
Vaseline (Sunwhite P-1, manufactured by Nikko Rica Corporation) was applied to the skin surface on the inside of a human left arm at a rate of about 1.5 mg/ ^cm2 to form a waterproof and moisture-permeable layer, and the polyvinyl alcohol film (thickness about 10 μm) obtained in Example 2 was attached on top of the layer.

Comparative Example 3
The amount of water lost from bare skin was measured.

<result>
As is clear from Table 2, the amount of moisture evaporation from the bare skin itself was greater in a low humidity environment than in a high humidity environment. On the other hand, in the case of Examples 4 and 5 in which the polyvinyl alcohol film was applied, no sticky discomfort was observed in a high humidity environment, and the amount of moisture evaporation in a low humidity environment was suppressed to be lower than that in a high humidity environment, and it was confirmed that the moisturizing performance of the skin in a low humidity environment can be improved. In addition, in a high humidity environment, the amount of moisture evaporation from the bare skin in Example 4 was greater than that of Comparative Example 3. This is thought to be due to the fact that the measurement site of the bare skin in Comparative Example 3 was different from the site where the PVA film in Example 4 was applied to the bare skin, that is, the amount of moisture evaporation from the bare skin at each measurement site was different.

100, 200, 300, 400 Moisture-retaining film cosmetic 101, 201, 301, 401 Polyvinyl alcohol film 103, 203, 303, 403 Polyvinyl alcohol molecule 105, 205, 305, 405 Moisture 107, 207, 307, 407 Gaps that allow moisture to pass through 408 Moisture passing through waterproof/moisture-permeable layer 409 Waterproof/moisture-permeable layer

Claims (16)

A cosmetic method (excluding medical procedures) in which a waterproof/moisture-permeable layer is applied to a body surface, and then a moisturizing polyvinyl alcohol film is applied to the body surface, or a cosmetic method (excluding medical procedures) in which a waterproof/moisture-permeable layer is applied to one side of a moisturizing polyvinyl alcohol film, and then the moisturizing polyvinyl alcohol film is applied to the body surface via the waterproof/moisture-permeable layer,
The waterproof and moisture-permeable layer is at least one selected from an oil layer, a polylactic acid layer, and an artificial skin,
When a laminate including the moisture-retaining polyvinyl alcohol film and the waterproof/moisture-permeable layer is evaluated in a moisture evaporation test, the amount of moisture evaporation measured in an environment of 23° C. and 40% RH is less than the amount of moisture evaporation measured in an environment of 28° C. and 70% RH.
Beauty methods. A cosmetic method (excluding medical procedures) in which a waterproof and moisture-permeable layer is applied to a body surface, and then a moisturizing polyvinyl alcohol film is applied to the body surface,
The waterproof and moisture-permeable layer is at least one selected from an oil layer, a polylactic acid layer, and an artificial skin,
When a laminate including the moisture-retaining polyvinyl alcohol film and the waterproof/moisture-permeable layer is evaluated in a moisture evaporation test, the amount of moisture evaporation measured in an environment of 23° C. and 40% RH is less than the amount of moisture evaporation measured in an environment of 28° C. and 70% RH.
Beauty methods. The thickness of the moisture-retaining polyvinyl alcohol film is 100 μm or less.
The cosmetic method according to claim 1 or 2 . The thickness of the moisture-retaining polyvinyl alcohol film is 10 μm or less.
The cosmetic method according to claim 3 . When the moisture-retaining polyvinyl alcohol film is evaluated in a moisture evaporation test, the moisture evaporation amount measured in an environment of 23° C. and 40% RH is less than the moisture evaporation amount measured in an environment of 28° C. and 70% RH.
The cosmetic method according to any one of claims 1 to 4 . The waterproof and moisture-permeable layer is the oil layer, and the oil layer contains at least one of Vaseline and liquid paraffin.
The cosmetic method according to any one of claims 1 to 5 . The waterproof and moisture-permeable layer is at least one selected from a polylactic acid layer and an artificial skin.
The cosmetic method according to any one of claims 1 to 5 . The application of the moisturizing polyvinyl alcohol film to the body surface is carried out by attaching it in the form of a self-supporting film;
The cosmetic method according to any one of claims 1 to 7 . The application of the moisturizing polyvinyl alcohol film to a body surface is carried out by applying a composition containing polyvinyl alcohol and water to the body surface.
The cosmetic method according to any one of claims 1 to 7 . The moisture-retaining polyvinyl alcohol film contains unmodified polyvinyl alcohol.
The cosmetic method according to any one of claims 1 to 9 . The thickness of the moisture-retaining polyvinyl alcohol film is 7 μm or less.
The cosmetic method according to any one of claims 1 to 10 . A cosmetic method (excluding medical procedures) in which a waterproof and moisture-permeable layer is applied to a body surface, and then a moisturizing polyvinyl alcohol film is applied to the body surface,
the application of the moisture-retaining polyvinyl alcohol film to a body surface is carried out by applying a composition containing polyvinyl alcohol and water to the body surface;
The application of the waterproof and moisture-permeable layer to the body surface is carried out by attaching it in the form of a free-standing film,
The waterproof and moisture-permeable layer is at least one selected from an oil layer, a polylactic acid layer, and an artificial skin.
Beauty methods. A cosmetic method (excluding medical procedures) in which a waterproof and moisture-permeable layer is applied to a body surface, and then a moisturizing polyvinyl alcohol film is applied to the body surface,
the application of the moisture-retaining polyvinyl alcohol film to a body surface is carried out by applying a composition containing polyvinyl alcohol and water to the body surface;
The application of the waterproof and moisture-permeable layer to the body surface is carried out by applying a waterproof and moisture-permeable layer component to the body surface ,
The waterproof and moisture-permeable layer is at least one selected from an oil layer, a polylactic acid layer, and an artificial skin.
Beauty methods. A polyvinyl alcohol film for use in the cosmetic method according to any one of claims 1 to 13 , or
A composition for producing the polyvinyl alcohol film,
A member to which a waterproof/moisture-permeable layer can be applied, the waterproof/moisture-permeable layer being at least one selected from an oil layer, a polylactic acid layer, and an artificial skin;
A cosmetic kit comprising: A polyvinyl alcohol film;
A waterproof and moisture-permeable layer disposed on one side of the polyvinyl alcohol film.
The waterproof and moisture-permeable layer is at least one selected from an oil layer, a polylactic acid layer, and an artificial skin,
When the laminate including the polyvinyl alcohol film and the waterproof moisture-permeable layer is evaluated in a moisture evaporation test, the moisture evaporation amount measured in an environment of 23°C and 40% RH is less than the moisture evaporation amount measured in an environment of 28°C and 70% RH.
Cosmetic kit. Further comprising a component layer used in combination with the polyvinyl alcohol film,
The constituent layer has a pressure-sensitive adhesive layer having through holes,
The cosmetic kit according to claim 15 .

Images