WO2019106750A1

WO2019106750A1 - Skin washing method and kit

Info

Publication number: WO2019106750A1
Application number: PCT/JP2017/042788
Authority: WO
Inventors: Panomporn TONGCHALAEM; Tongta YUWANAKORN; Sopit YONGYUT; Pornsuda HOMRARUEN
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2017-11-29
Filing date: 2017-11-29
Publication date: 2019-06-06
Anticipated expiration: 2020-05-29
Also published as: CN111405929A; JP2021504406A

Abstract

To provide a method for skin washing quickly and easily. A skin washing method comprising the steps of: (a) mixing water and a composition comprising a carbonate and/or a bicarbonate, and an acid in a container to obtain a fluid mixture, wherein a mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is 0.005 or more and 0.05 or less, and a proportion of the water to an internal volume of the container is 0.3 or more and 0.9 or less; (b) sealing the container containing the fluid mixture; (c) making carbon dioxide generated in the container supersaturated; and (d) releasing the fluid mixture from the container and applying the fluid mixture to a skin.

Description

[Title established by the ISA under Rule 37.2] SKIN WASHING METHOD AND KIT

Field of the Invention

The present invention relates to a skin washing method in an easy and quick manner.

Background of Invention

Conventionally, as means for washing the skin and relaxing, baths and showers are widely used. For example, a technique of rapidly removing the influence of excessive stress and refreshing body and mind with a bath agent containing an extract of Cnidium officinale of the family Umbelliferae and/or an extract of Matricaria recutita of the family Compositae and an extract of Mentha of the family Labiatae and/or an extract of Rosmarinus officinalis of the family Labiatae is known (Patent Literature 1).

In bathing, a carbon dioxide-generating bath agent having a blood circulation promotion effect is used, and a relaxing effect, a refreshing effect, a fatigue recovery effect, and the like are obtained (Patent Literature 2). Further, as a washing technique using carbon dioxide gas, a technique of washing the head such as the scalp and parts such as the buttocks by a particular washing apparatus is also known (Patent Literature 3).

(PTL 1) Japanese Laid-open Patent Publication No. 2005-29536
(PTL 2) Japanese Laid-open Patent Publication No. hei 11-47221
(PTL 3) Japanese Laid-open Patent Publication No. 2003-93262

The present invention relates to a skin washing method comprising the steps of:
(a) mixing water and a composition comprising a carbonate and/or a bicarbonate, and an acid in a container to obtain a fluid mixture, wherein a mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is 0.005 or more and 0.05 or less, and a proportion of the water to an internal volume of the container is 0.3 or more and 0.9 or less;
(b) sealing the container containing the fluid mixture;
(c) making carbon dioxide generated in the container supersaturated; and
(d) releasing the fluid mixture from the container and applying the fluid mixture to a skin.

illustrates a schematic view of a container according to the present invention. illustrates a schematic view of a cap according to the present invention. illustrates an embodiment of Step (a). illustrates an embodiment of Step (c). illustrates an embodiment of Step (d). illustrates a sachet containing a composition (powder) inside. illustrates an inner strainer attachable inside the container. illustrates a dip tube when the container is flipped upside down. illustrates hole dimensions, appearance of the ejection port of the cap, and the result of jetting the fluid mixture.

Means for washing the skin and relaxing vary from country to country because of cultural and climatic difference. For example, Japanese like taking baths and showers, while Southeast Asian people prefer pouring water with bucket or taking showers.

Detailed Description of Invention

However, in recent years, the numbers of people who are busy, get up to work early and work late into the night and people who enjoy hobbies or social activities late into the night have been increasing, regardless of the nation or the district where they live. Meanwhile, when a bath or a shower is taken to wash the skin fully, several tens of minutes are required, including rinsing off detergent, drying and subsiding the sweat, and the like. In this manner, for busy people of recent years, simple and quick skin washing and/or refreshing method which may replace bathing or showering has been desired. Pouring water alone over the body may replenish the desire to wash the skin or refresh in little time indeed, but the method hardly washes the body fully nor gives long-lasting freshness.

Conventional washing technique using carbon dioxide gas is designed for topical use, but the structure of apparatus for it is complex or requires installation with water supply. Therefore, the washing technique was not suitable as a simple and quick skin washing and/or refreshing method, and a new washing method to replace the conventional method is desired.

Accordingly, the present invention relates to providing a new method for simply washing the skin easily and quickly without limitation of place, e.g., inside or outside a building.
The present inventor has focused on a container containing water, and a carbon dioxide-generating agent containing a carbonate and/or a bicarbonate, and an acid. The present inventor has found that when mixing the carbon dioxide-generating agent with the water in the container, which is then sealed, and making carbon dioxide generated in the sealed container supersaturated before reopening the container to jet the carbonated solution out from the container, it is possible to wash the skin, to refresh the skin, and also to possibly promote blood circulation with the carbonated solution in a quick and easy manner. Further, the method is not limited to in-house use but can be carried out outdoors, e.g., a garden, a beach, a mountain, a forest, a riverside, a field.

The method according to the present invention allows jetting an aqueous carbon dioxide-containing fluid mixture onto the skin quickly and easily, to impart washing effect, refreshing effect and the like.

The skin washing method according to the present invention comprises the following steps (a), (b), (c) and (d):
(a) mixing water and a composition comprising a carbonate and/or a bicarbonate, and an acid in a container to obtain a fluid mixture, wherein a mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is 0.005 or more and 0.05 or less, and a proportion of the water to an internal volume of the container is 0.7 or more and 0.9 or less;
(b) sealing the container containing the fluid mixture;
(c) making carbon dioxide generated in the container supersaturated; and
(d) releasing the fluid mixture from the container and applying the fluid mixture to a skin.

Each step will be explained hereafter.

The skin washing method according to the present invention comprises a container having a sealable cap, water, and a composition comprising a carbonate and/or a bicarbonate, and an acid (also referred to as a carbon dioxide-generating agent). In the present invention, skin may encompass an entire body or a partial body, including a scalp, a face, a neck, a shoulder, a breast, a belly, a waist, a back, a buttock, a hand, a palm, an arm, an elbow, a leg, an ankle, a foot, a toe, a sole, a heel and the like. Among them, the skin washing method according to the present invention is preferably a body washing method.

The container is not particularly limited as long as it may take in liquid such as water inside. The container may be a bottle, a jug, a jar, a tube, or the like. The container is preferably pressure-proof. As water, not only tap water but also deionized water or mineral water may be used. The container may be made of resin, glass, metal, or the like. As the material for the container, resin may be preferable in terms of light weight, accessibility and easiness of manufacturing. A polyethylene-based resin is more preferable, and polyethylene terephthalate (PET) resin as an example illustrated in Fig. 1 is further more preferable.

The internal volume of the container is not particularly limited but is preferably 300 mL or more and 3 L or less, more preferably 350 mL or more and 2 L or less, as the volume at which the container can be filled with water, in terms of usability and shower time period.

The size of the container can be varied in accordance with application, and may not be determined categorically. If the size of the container has the internal volume of 400 mL or more and 600 mL or less, from similar viewpoints, the maximum inner diameter of the container is preferably 50 mm or more and 135 mm or less, more preferably 55 mm or more and 115 mm or less, and further more preferably 60 mm or more and 85 mm or less. The height of the container is preferably 200 mm or more and 320 mm or less, more preferably 200 mm or more and 270 mm or less, and further more preferably 200 mm or more and 240 mm or less. In the present invention, the maximum inner diameter of the container is defined such that when a container stands upright, it is the maximum inner diameter among diameters of the horizontal cross section of the container. If the cross section is not circle, it is the diameter of imaginary circle having equivalent area.

The skin washing method according to the present invention may be easily handled such that even a woman, a child, or an elderly person can easily hold it, and therefore it is not physically burdensome. For example, for a woman and a child, the internal volume is preferably 300 mL or more and 1 L or less in view of improving the usability.

In addition, because of its moderate size, adequate amount of carbon dioxide can be generated by sufficient mixing of the carbonate and/or the bicarbonate, and the acid with the water. When the container has such a size, continuous washing and refreshing effects could be enjoyed after the fluid mixture is released from the container at moderate pressure.

The cap of the container may be configured to be sealable and to be releasable of the fluid mixture in the container, in terms of sealing the fluid mixture in Step (b) and in terms of releasing the fluid mixture from the container via the cap in Step (d). The cap may be configured to be sealable and to be releasable of the fluid mixture, such as a push-pull cap, a flip-up cap, or a screw cap. Further, the cap may be provided with an ejection port. One of the embodiments of cap is the cap having inner and outer ejection ports, and fluid mixture goes through the inner port and jets out of the outer port. An ejection port diameter adjustment function is preferably provided in the cap. For example, it is preferable that a cap be configured such that the ejection port diameter can be adjusted in a screw manner.

In terms of releasing the fluid mixture comprising the carbon dioxide from the container and continuously exhibiting the cleansing effect, and refreshing effect of the fluid mixture, and probably blood circulation promotion effect, that is, the carbon dioxide-containing aqueous solution (the fluid mixture may be hereinafter referred to as the carbon dioxide-containing aqueous solution), in Step (d), a cap provided with a dip tube is also preferable (Fig. 2). Further, the dip tube has a length reachable at the container bottom.

In the method of the present invention, by Step (a), the carbonate and/or the bicarbonate is neutralized by the acid, and carbon dioxide is generated. Then, the container is sealed by Step (b), and the generated carbon dioxide is partially dissolved into water and partially in gaseous form combined with the air in the headspace (the portion in the container other than the fluid mixture). The generated carbon dioxide gas in the headspace gives pressure to the fluid mixture.

However, by Step (d), such pressure is reduced, and the fluid mixture is instantaneously discharged out of the container. For the purpose of discharging instantaneously, one of the effective methods is to put the container upside-down before releasing the fluid mixture, and another method is to use the container providing the dip tube. With such methods, the carbon dioxide is released through the tube, and therefore the effects of the present invention can be enjoyed continuously to some extent.

The following describes a composition comprising a carbonate and/or a bicarbonate, and an acid (the composition being a carbon dioxide-generating agent).

The carbonate and/or bicarbonate as used in the present invention is a component to generate carbon dioxide by means of neutralization by an acid, as described hereafter. The generated carbon dioxide is soluble in water, and as well it imparts a washing effect and a refreshing sensation when it is applied to skin. It is expected that it exerts a blood circulation promoting effect.

Carbonates and/or bicarbonates include one or more selected from the group consisting of sodium carbonate, sodium bicarbonate, magnesium carbonate, calcium carbonate and potassium carbonate. Particularly, in terms of imparting excellent foamability, that is, ability to generate bubble, one or more selected from the group consisting of sodium carbonate and sodium bicarbonate are preferable.

Acids are preferably an organic acid in terms of securing storage stability. Organic acids include, for example, succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, benzoic acid, citric acid, pyroglutamic acid, salicylic acid, maleic acid, phthalic acid, glutaric acid, oxalic acid, and the like, one or more of which may be employed. Among them, for the same reason, one or more selected from the group consisting of succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, benzoic acid, citric acid, pyroglutamic acid and salicylic acid are preferable. For the same reason, one or more selected from the group consisting of succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, and citric acid are more preferable. For the same reason, one or more selected from the group consisting of succinic acid, malic acid, and fumaric acid are further more preferable.

The total content of the carbonate and bicarbonate in the composition is preferably 5% or more and 80% or less by mass, more preferably 10% or more and 60% or less by mass, in terms of enhancing the carbon dioxide generation effect, washing effect, refreshing effect and blood circulation promotion effect.

The content of the acid is preferably 10% or more and 80% or less by mass, more preferably 15% or more and 60% or less by mass in total, in terms of the same reasons above.

The composition may comprise additional agents such as a water-insoluble or hardly water-soluble powder, a cooling agent, an ultraviolet absorber agent, a conditioning agent, essential oil, a fragrant agent, an excipient, a binder, a disintegrant, an extract from animals or plants, an antiseptic, a dye, a perfume, an oily component, a surfactant, or the like.

According to the skin washing method according to the present invention, the skin can be washed by applying an aqueous carbon dioxide-containing fluid mixture in a fairly sustainable manner for a while without or with small amount of surfactant. Therefore, an embodiment of the present invention comprises 2% by mass or less, preferably 1% by mass or less of surfactant in relation to the total composition. This means that one of the embodiment of our invention contains a substantially surfactant-free method.

The water-insoluble or hardly water-soluble powder includes, a silicone powder, bentonite, aluminum potassium sulfate, zinc phenol sulfonate and the like. The content of the water-insoluble powder is, for example, preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 2% or less, further more preferably 0.2% or more and 1% or less, in terms of imparting skin freshness and smoothness of skin after the showering.

Cooling agents include menthol, camphor, monomenthylglyceryl ether, menthyl lactate, and the like. The content of the cooling agent in the composition is, for example, preferably 0.01% or more and 5% or less, more preferably 0.01% or more and 0.1% or less by mass in terms of imparting a cooling effect.

Conditioning agents include polyhydric alcohols intended for moisturizing, reducing scaling and stimulating removal of built-up scale from the skin. Typical polyhydric alcohols include polyalkylene glycols and more preferably alkylene polyols and their derivatives, e.g., propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerin, propoxylated glycerin and mixtures thereof.

Ultraviolet absorber agents include para-aminobenzoic acid, octyl-p-methoxy-cinnamate (2-ethylhexyl-p-methoxy-cinnamate), glycerylmono-2-ethylhexanoyl diparamethoxycinnamate, silyl isopentyl trimethoxycinnamate trisiloxane and other cinnamic acid based ultraviolet absorbers, 2,2'-hydroxy-5-methyl phenylbenzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methyl phenylbenzotriazole, 4-methoxy-4'-t-butyldibenzoylmethane, 5-(3,3-dimethyl-2-norbornylidene)-3-pentan-2-one, bis-ethylhexyloxyphenol-methoxyphenyl triazine, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]1,3,5-triazine, dimorpholinopyridazinone.

Essential oil includes, amber oil, bergamot, cedarwood, chamomile oil, cinnamon oil, citronella oil, cypress oil, eucalyptus oil, geranium oil, ginger oil, grapefruit oil, honey oil, jasmine oil, lavender oil, lemon oil, lime oil, lemongrass oil, neroli oil, perilla oil, rose oil, rosemary oil, sandalwood, tangerine oil, teatree oil, thyme oil, ylang ylang oil, and the like.

Fragrant agents include, aside from the essential oil, aldehyde, ketone, ester, and the like, but not limited thereto.

Excipients include, for example, a water-soluble binder. When acid is coated with a water-soluble binder, a reaction is suppressed in the package container during storage before use, whereas it can generate carbon dioxide effectively in use.

The water-soluble binder is preferably at least one kind selected from the group consisting of polyethylene glycol, polypropylene glycol, polyoxyethylene alkyl ether and polyoxyethylene phenol ether, and more preferably at least one selected from the group consisting of polyethylene glycol and polypropylene glycol.

The number average molecular weight of the water-soluble binder is, in terms of balancing viscosity control and handling in pulverization, preferably 4,000 or more and 20,000 or less, more preferably 6,000 or more and 13,000 or less, and further more preferably 7,000 or more and 9,000 or less by a GPC method where polystyrene is used as a standard. In order to measure polyethylene glycol as a water-soluble binder, a mixture of water / ethanol may be employed as a solvent.

When the water-soluble binder is used, two or more water-soluble binders having different number average molecular weights may be combined.

The content ratio of the excipient to acid (excipient/acid) is preferably 2% or more and 20% or less by mass in terms of improving the coating efficiency, and more preferably 5% or more and 15% or less by mass. In the above range, higher solubility in water and higher foamability are obtained.

The additional agents described above are not limited to the intended use, and may be used for other use depending on a purpose, for example, a fragrant agent may be used as a cooling agent, or may be used also for other use in addition to their intended use, for example, as one having effects of a fragrant agent and a cooling agent.

The form of the composition may be a solid such as granules, powders, tablets, briquettes, or the like in terms of quick dissolution in water and generating carbon dioxide, and in terms of improving the stability of carbonate or bicarbonate. Tablets may be molded by a rotary tableting machine, a hydraulic tableting machine, an eccentric tableting machine, a briquetting machine, a compacting machine, or the like.

Among them, tablets are preferable in view of bringing them easily into the container. They can generate carbon dioxide within the water after they sink toward the container bottom, and they may be dissolved in water preferably in 15 seconds or more and 120 seconds or less, more preferably in 20 seconds or more and 90 seconds or less, further more preferably in 25 seconds or more and 70 seconds or less in view of generating carbon dioxide-containing fluid mixture having a proper pressure. For longer duration, it is also preferable to shake the container containing the fluid mixture to leave 10% or more and 30% or less, preferably 15% or more and 25% or less of carbonate or bicarbonate undissolved. After the onset of releasing the fluid mixture, flow rate gradually decreases. Nevertheless, if there remains undissolved carbonate or bicarbonate (residue) in water, for example, by shaking the container again, carbon dioxide gas can be re-generated.

The average particle size of the tablet is preferably 1 mm or more and 12 mm or less, more preferably 1.5 mm or more and 11 mm or less, and further more preferably 1.8 mm or more and 10 mm or less. The average particle size may be determined as the particle size distribution which may be measured in accordance with JIS K 0069. The average height (thickness) is preferably 0.8 mm or more and 10 mm or less, more preferably 1.0 mm or more and 8 mm or less, and further more preferably 2 mm or more and 7 mm or less. In the present invention, on the condition that the tablet stands upright, the average particle size means the horizontally largest size, and the average height means the vertically highest size. The shape of the tablet is not limited to a special shape, but may be spherical or non-spherical and/or may be symmetric or asymmetric.

Here, the average particle size and the average tablet height (thickness) represent average of maximum diameter and average of the maximum height (thickness) of projected area.

The density of the tablet is not limited as long as it is larger than that of water (1.0 at 4°C) in view of quickly sinking tablets into the bottom of water and dissolving into water, preferably 1 or more, more preferably more than 1, further more preferably 1.1 or more and 2.5 or less. The density of the tablet may be calculated by measuring its weight and volume, and then dividing the weight by the volume.

When the average particle diameter and the density of the tablets are in the above ranges, the tablets dissolve moderately when the tablets are mixed with water to obtain a mixed solution. "Dissolve moderately" means that most of the tablets are dissolved, but some undissolved ones remain. A fixed amount of the carbon dioxide-containing aqueous solution can be continuously applied to the skin by the method of the present invention. For this purpose, it is preferable that the tablets do not dissolve completely immediately and that some are left undissolved in the fluid mixture. Namely, carbon dioxide gas can be further generated by taking the step of generating carbon dioxide again after changing the state of the container from the released state to the sealed state when the pressure weakens during the application of the carbon dioxide-containing fluid mixture to the skin. Therefore, the carbon dioxide-containing aqueous solution having pressure enough to wash and give freshness can be continuously applied to the skin.

Powder is preferable in view of quick dissolution into water. The time for dissolving the powder in water is for example, preferably 1 second or more and 20 seconds or less, more preferably 5 seconds or more and 20 seconds or less, further more preferably 5 seconds or more and 10 seconds or less. The average particle size contained in the powder is not limited, but for example, preferably 0.01 mm or more and 12 mm or less. The average particle size may be determined as the particle size distribution which may be measured in accordance with JIS K 0069. The apparent density may be measured in accordance with JIS K 3362. Further, in view of preventing powders from caking together, anticaking agents are preferably contained in the powders. Preferable anticaking agents include, MgO, SiO₂, Ca₂O₄Si, Mg₃Si₄O₁₀(OH)_2,talc, kaolin, bentonite, and the like.

Indeed powder is preferable in view of quick dissolution into water, but the too quick dissolution might lead to quick reaction of a carbonate and/or a bicarbonate and an acid. It can result in overflowing the fluid mixture. In view of balancing dissolution speed, powder may be stored in a sachet which may be porous or water-soluble to delay the dissolution of the powder in water. The sachet containing the powder therein may be put into the container for Step (a).

Fig. 6 illustrates an embodiment of the composition comprising a carbonate and/or a bicarbonate and an acid (as multiple powders 10) is enclosed in a tetrahedron sachet 100. The material for the sachet 100 is not particularly limited as long as it delays dissolution of the composition in water, but the sachet may be made of a mesh material, a filter paper, a nonwoven (e.g., polyethylene), a water-soluble film (e.g., polyvinyl alcohol), or the like. In Fig. 6, the powders 10 are enlarged for better understanding. For example, the powder may be put inside the sachet prior to being brought into the container. The sachet can prevent the powder from direct contact with water and delay its dissolution in water.

In another embodiment, the composition may be put into an inner strainer. Fig.7 illustrates an embodiment of an inner strainer 20. The inner strainer 20 is provided with multiple meshes 22. The inner strainer 20 is configured to be attachable inside the container. For example, when the composition is a powder, the powder may be put into the inner strainer provided in the container for Step (a). The strainer structure delays dissolution of the composition in water. In Fig. 7, the inner strainer 20 is provided with a cap receiver 24 at the upper end. In Fig. 7, the cap receiver 20 is configured to be attachable to a cap via a screw structure. Additionally or alternatively, the cap receiver 20 may be configured to be attachable to an ejection port via the screw for easy discharge of the fluid mixture.

In Step (a), water and a composition containing a carbonate and/or a bicarbonate, and an acid are mixed in a container to obtain a fluid mixture (Fig. 3). Namely, water and the above composition are mixed in the container, for example, (i) by introducing the above composition into the container containing water, by adding the above composition to water and immediately introduce the fluid mixture into the container, (ii) by simultaneously or separately introducing water and the above composition into the container, or (iii) by introducing water into the container containing the above composition. The volume of water to be introduced into the container is not limited, but it may be 300 mL or more and 3 L or less, more preferably 350 mL or more and 2 L or less, and further more preferably 350 mL or more and 1 L or less, within the internal volume of the container. In an embodiment, it is preferable that a volume of the water in the container be 300 mL or more and 3 L or less, and the container is made of a resin.

Here, the mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is preferably 0.005 or more and 0.5 or less, more preferably from 0.006 or more and 0.3 or less, and further more preferably 0.007 or more and 0.1 or less in terms of obtaining a sufficient high concentration carbon dioxide-containing aqueous solution and in terms of obtaining sufficient jet force. In this invention, (i) the total content of the carbonate and the bicarbonate means the amount to be introduced into water or the amount in the composition to be introduced.

The mass ratio of (iii) the composition to (ii) water in the container, [(iii)/(ii)], is preferable 0.007 or more and 0.08 or less, more preferably 0.009 or more and 0.06 or less, and further more preferably 0.01 or more and 0.05 or less, in terms of obtaining sufficiently high concentration of an aqueous carbon dioxide-containing solution and imparting sufficient injection force.

The proportion (volume ratio) of the water to the internal volume of the container (water/internal volume) is preferably 0.3 or more and 0.9 or less, more preferably 0.5 or more and 0.9 or less, and further more preferably from 0.7 to 0.9 in terms of obtaining a high concentration carbon dioxide-containing aqueous solution, in terms of generating a sufficient amount of carbon dioxide when shaking the container in Step (c).

The volume ratio of the headspace to the carbon dioxide-containing fluid mixture after the step of generating carbon dioxide in Step (c) (headspace/fluid mixture) is preferably 0.1 or more and 2.3 or less, more preferably 0.1 or more and 1.0 or less, and further more preferably 0.1 or more and 0.4 or less in terms of obtaining a high concentration carbon dioxide-containing aqueous solution, in terms of generating a sufficient amount of carbon dioxide when taking the step of generating carbon dioxide in Step (c).

The temperature of the water to be used is preferably 20°C or higher and 43°C or lower in terms of solubility of carbonates or bicarbonates, and refreshing sensation when the fluid mixture is jetted onto the skin. In view of improving refreshing effect, the temperature of the water to be used is preferably 20°C or higher and 35°C or lower, more preferably 25°C or higher and 35°C or lower. In view of improving warming effect, the temperature is preferably 30°C or higher and 42°C or lower, more preferably 38°C or higher and 42°C or lower.

Step (b) is the step of sealing the container containing the fluid mixture. Specifically, the container may be sealed with the above sealable cap.

Step (c) is the step of making carbon dioxide generated in the container supersaturated. Examples of the step of generating carbon dioxide include means such as allowing the container to stand and shaking the container by hand or agitating the fluid mixture by machine. In terms of efficiently generating carbon dioxide in a short time, shaking the container by hand (Fig. 4) is preferable. By this Step (c), a large amount of carbon dioxide may be generated in the fluid mixture.

The frequency of shaking the container may vary, depending on the purpose of the present invention. For example, if one desires to enjoy strong pressure from carbon dioxide-containing aqueous solution, one can shake the container at high frequency. Otherwise, if one desires to enjoy the application for a longer time, one can shake the container at low frequency. The frequency may be determined by observing how well the carbonates or bicarbonates are dissolved into water. For longer duration, it is preferable to shake the container so as to dissolve preferably from 70% to 90%, more preferably from 75% to 85% of carbonates or bicarbonates into water.

Step (d) is the step of releasing the fluid mixture from the container and applying the fluid mixture to the body (Fig. 5). Specifically, when the container is opened, the fluid mixture pushed out by gas pressure is vigorously jetted from the container because a large amount of carbon dioxide is generated inside the container. Thus jetted fluid mixture can be applied to the body.

Here, the fluid mixture ejection time is, in total, preferably 15 seconds or more and 3 minutes or less, more preferably 30 seconds or more and 2 minutes or less, and further more preferably 45 seconds or more and 90 seconds or less, in terms of washing simply and in a short time. In order to adjust the ejection time in this range, the ejection speed may be adjusted, and the ejection speed is determined by the mass ratio of the total content of the carbonates and the bicarbonates to the water in the container and the proportion of the water to the internal volume of the container described above, the amount of the water in the container, the inner and outer diameters of the ejection port of the container, and the like. The place of the ejection port is not limited, and one of the embodiments is that the ejection port is provided at a container, and another embodiment is that the ejection port is provided at a cap. The ejection port comprises outer port and inner port. The outer port can be seen from outside of the container, while the inner port is the other side of the outer port. Fluid mixture is supposed to go through the inner port and then jet out of the outer port.

The number of ejection ports or the inner and outer diameter of each ejection port of the container may not be limited. The number of ejection port is one or more, preferably 1 or more and 60 or less, and more preferably 1 or more and 40 or less. Another embodiment of the number of ejection ports is dependent on the ratio of outer diameter of an ejection port to diameter of showering area, and the ratio of total area of ejection ports to showering area. Showering area is defined as an area that has either a single ejection port or a number of ejection ports arranged in a pattern which has an imaginary circle drawn from the farthest points at the rim of the most outer port to another one. The ratio of outer diameter of an ejection port to diameter of showering area is preferably 0.01 or more and 0.3 or less, and more preferably 0.05 or more and 0.17 or less. The ratio of total area of ejection ports to showering area is preferably 0.01 or more and 0.2 or less, and more preferably 0.03 or more and 0.1 or less. The inner diameter of the ejection port is preferably 0.01 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 4 mm or less. The outer diameter of the ejection port is preferably 0.01 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 4 mm or less.

The form of the ejection port is represented by the relationship between the ejection port on the outer outlet side where the fluid mixture is ejected and the ejection port on the inlet side leading to the ejection side. Namely, the form of the ejection port may be a conical shape in which the port diameter increases or decreases upward from below (toward the ejection port from the lower portion of the container), may be vertically straight, or may be slanted upward from below or downward from above. Specific examples include one conical ejection port whose port diameter increases upward from below, 2 to 30 straight ejection ports, and 2 to 30 ejection ports slanted upward from below as shown in Fig. 9.

By adjusting the inner diameter of the ejection port, the time of jetting the fluid mixture out of the container can be adjusted. Namely, when a sufficient amount of carbon dioxide is generated inside the container by the step of making carbon dioxide generated in the container supersaturated, Step (c), jetting time of the fluid mixture can be sufficiently increased when the inner diameter of the ejection port is decreased. For example, when the volume of the fluid mixture is 400 mL or more and 1 L or less, the inner diameter of each ejection port may be 1 mm or more and 4 mm or less when it is intended to adjust the jetting time to be 45 seconds or more and 2 minutes or less, preferably 45 seconds or more and 90 seconds or less.

The shape of the ejection port may be circular, elliptical, polygonal, or the like and is not particularly limited. It is preferably circular in terms of applying the fluid mixture in a constant manner to the desired sites.

Fig. 8 illustrates a dip tube in a container when the container is flipped upside down. In this embodiment, the dip tube has a weight at the tip. When the container is flipped upside down, the tip of the dip tube is lowered so that the fluid mixture can be kept discharged from the container regardless of reduction in its volume. The dip tube is preferably a flexible tube attached with a weight to bend easily when the container is flipped upside down.

Steps (b) to (d) or Steps (c) to (d) may follow Step (d) repeatedly.

The method according to the present invention can also contain an additional step; Step(e) squeezing the container to release the fluid mixture. Further after or before applying a conventional shower, which has no carbonate, the method according to the present invention can also be applied. The method according to the present invention can include a method without any other step, where no rinsing step or drying step is included.

By jetting the fluid mixture containing a large amount of the carbon dioxide onto the skin, the skin surface can be washed, and the refreshing effect on the skin surface, and probably the blood circulation promotion effect could be obtained. What is more, these effects are obtained in a very short time and by an easy action. On top of that, the method according to the present invention can release higher content of carbon dioxide mixture, because water and a composition comprising a carbonate and/or a bicarbonate are separately prepared before use but are to be mixed just in application.

Also the method according to the present invention can release to an entire body not only higher content of carbon dioxide mixture, but also a cooling agent, an ultraviolet absorber agent, a conditioning agent, a fragrant agent or the like by using that composition containing such agents. That is, the present invention can be available as leave-on type cosmetic which do not require a rinsing step with water.

The present invention further relates to a skin washing agent kit. The skin washing agent kit of the present invention may comprise a container, a cap, and a composition comprising a carbonate and/or a bicarbonate, and an acid, all of which are described hereinbefore. The skin washing kit may be used in the skin washing method of the present invention.

With respect to the above embodiment, the present invention further discloses the following washing methods.
<1> A skin washing method comprising the steps of:
(a) mixing water and a composition comprising a carbonate and/or a bicarbonate, and an acid in a container to obtain a fluid mixture, wherein a mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is 0.005 or more and 0.05 or less, and a proportion of the water to an internal volume of the container is 0.7 or more and 0.9 or less;
(b) sealing the container containing the fluid mixture;
(c) making carbon dioxide in the container; and
(d) releasing the fluid mixture from the container and applying the fluid mixture to a skin.

<2> The skin washing method according to <1>, wherein the container is made of resin, preferably made of polyethylene-based container, and more preferably made of polyethylene terephthalate (PET).

<3> The skin washing method according to <1> or <2>, wherein the internal volume of the container is preferably 300 mL or more and 3 L or less, more preferably 350 mL or more and 2 L or less.

<4> The skin washing method according to any one of <1> to <3>, wherein the maximum inner diameter of the container is preferably 50 mm or more and 135 mm or less, more preferably 55 mm or more and 115 mm or less, much more preferably 60 mm or more and 85 mm or less, and/or the height of the container is preferably 200 mm or more and 320 mm or less, more preferably 200 or more and 270 mm or less, and further more preferably 200 or more and 240 mm or less.

<5> The skin washing method according to any one of <1> to <4>, wherein the container comprises a cap provided with an ejection port and the cap is configured to be sealable.

<6> The skin washing method according to any one of <1> to <5>, wherein the container further comprises a dip tube having a length reachable at the container bottom.

<7> The skin washing method according to any one of <1> to <6>, wherein the dip tube is a flexible tube attached with a weight to bend easily when the container is flipped upside down.

<8> The skin washing method according to any one of <1> to <7>, wherein the acid is an organic acid, preferably one or more selected from the group consisting of succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, benzoic acid, citric acid, pyroglutamic acid, salicylic acid, more preferably one or more selected from the group consisting of succinic acid, fumaric acid, malic acid, adipic acid, tartaric acid, benzoic acid, citric acid, and further more preferably one or more selected from the group consisting of succinic acid, fumaric acid, and malic acid.

<9> The skin washing method according to any one of <1> to <8>, wherein the total content of carbonate and bicarbonate is 5% or more and 80% or less, more preferably 10% or more and 60% or less by mass, and/or the amount of the acid is 10% or more and 80% or less, more preferably 15% or more and 60% or less by mass.

<10> The skin washing method according to any one of <1> to <9>, wherein the composition further comprises one or more of a water-insoluble or hardly water-soluble powder, a cooling agent, an ultraviolet absorber agent, a conditioning agent, essential oil, a fragrant agent, an excipient, a binder, a disintegrant, an extract from animals or plants, an antiseptic, a dye, a perfume, an oily component, and a surfactant.

<11> The skin washing method according to <10>, wherein water-insoluble or hardly water-soluble powder is selected from the group consisting of a silicone powder, bentonite, aluminum potassium sulfate, and zinc phenol sulfonate.

<12> The skin washing method according to <10>, wherein the cooling agent is selected from the group consisting of menthol, camphor, monomenthylglyceryl ether and menthyl lactate.

<13> The skin washing method according to <10>, wherein the unltraviolet absorber agent is selected from the group consisting of para-aminobenzoic acid, octyl-p-methoxy-cinnamate (2-ethylhexyl-p-methoxy-cinnamate), glycerylmono-2-ethylhexanoyl diparamethoxycinnamate, silyl isopentyl trimethoxycinnamate trisiloxane and other cinnamic acid based ultraviolet absorbers, 2,2'-hydroxy-5-methyl phenylbenzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methyl phenylbenzotriazole, 4-methoxy-4'-t-butyldibenzoylmethane, 5-(3,3-dimethyl-2-norbornylidene)-3-pentan-2-one, bis-ethylhexyloxyphenol-methoxyphenyl triazine, 2,4,6-tris[4-(2-ethylhexyloxycarbonyl)anilino]1,3,5-triazine, dimorpholinopyridazinone.

<14> The skin washing method according to <10>, wherein the conditioning agent is selected from the group consisting of propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol, sorbitol, hydroxypropyl sorbitol, hexylene glycol, 1,3-butylene glycol, 1,2,6-hexanetriol, ethoxylated glycerin, and propoxylated glycerin.

<15> The skin washing method according to <10>, wherein the essential oil is selected from the group consisting of amber oil, bergamot, cedarwood, chamomile oil, cinnamon oil, citronella oil, cypress oil, eucalyptus oil, geranium oil, ginger oil, grapefruit oil, honey oil, jasmine oil, lavender oil, lemon oil, lime oil, lemongrass oil, neroli oil, perilla oil, rose oil, rosemary oil, sandalwood, tangerine oil, teatree oil, thyme oil, ylang ylang oil.

<16> The skin washing method according to any one of <1> to <15>, wherein the composition is a tablet.

<17> The skin washing method according to <16>, wherein the average particle size of the tablet is preferably 1 mm or more and 12 mm or less, more preferably 1.5 mm or more and 11 mm or less, and further more preferably 1.8 mm or more and 10 mm or less.

<18> The skin washing method according to any one of <1> to <17>, wherein the mass ratio of (i) the total content of carbonate and bicarbonate to (ii) water, [(i)/(ii)], is preferably 0.006 or more and 0.3 or less, and more preferably 0.007 or more and 0.1 or less.

<19> The skin washing method according to any one of <1> to <18>, wherein the mass ratio of (iii) the composition to (ii) water in the container, [(iii)/(ii)], is preferably 0.007 or more and 0.08 or less, more preferably 0.009 or more and 0.06 or less, and further more preferably 0.01 or more and 0.05 or less.

<20> The skin washing method according to any one of <1> to <19>, wherein the proportion (volume ratio) of water to the internal volume of the container is preferably 0.3 or more and 0.9 or less, more preferably 0.5 or more and 0.9 or less, and further more preferably 0.7 or more and 0.9 or less by mass.

<21> The skin washing method according to any one of <1> to <20>, wherein the temperature of the water to be used is preferably 20°C or more and 43°C or less, more preferably 20°C or more and 35°C or less and/or 30°C or more and 43°C or less.

<22> The skin washing method according to any one of <1> to <21>, wherein the jetting time of the fluid mixture is preferably
15 seconds or more and 3 minutes or less, more preferably 30 seconds or more and 2 minutes or less, and further more preferably 45 seconds or more and 90 seconds or less.

<23> The skin washing method according to any one of <1> to <20>, wherein the container is provided with one or more ejection ports, preferably 1 or more and 60 or less ejection ports, and more preferably 1 or more and 40 or less ejection ports.

<24> The skin washing method according to any one of <1> to <23>, wherein the inner diameter of the ejection port is preferably 0.01 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 4 mm or less, and/or the outer diameter of the ejection port is preferably 0.01 mm or more and 5 mm or less, and more preferably 0.1 mm or more and 4 mm or less.

<25> The skin washing method according to any one of <1> to <24>, wherein the ejection port has a conical shape in which the port diameter increases upward from below, a vertically straight shape, or a slanted shape upward from below.

<26> The skin washing method according to any one of <1> to <15>, wherein the composition is a powder and the powder is put inside a sachet prior to being brought into the container.

<27> The skin washing method according to any one of <1> to <15>, wherein the composition is a powder and the powder is put into an inner strainer provided in the container.

Examples

The present invention will be explained in more detail by way of Examples, but the scope of the present invention is not limited to the Examples.

Example 1

(1) Preparation of Tablets
Tablet A, Tablet B, and Tablet C shown in Table 1 were mixed and compression-molded by a tablet manufacturing apparatus.

(2) Apparatus
A PET bottle with a cap (bottle port diameter: approximately 2.5 cm; bottle height: approximately 20.5 cm; bottle barrel diameter: approximately 6.6 cm) was provided, in which 123 mL of headspace would be produced when the PET bottle was filled with 400 mL of water. The cap is provided with a screw-type resealable mechanism and ejection ports having a port diameter of 1 mm or more and 4 mm or less (shape: straight, number of ports: 6).

*other ingredients of Tablet A: glucose, PEG6000, MgO, Ca₂O₄Si, silicate, Sucrose fatty acid ester, glycine, perfume and colorant.
*other ingredients of Tablet B: Al₂(SO₄)₃・16H₂O, menthol, tea extract, polyoxyethylene (caprylic/capric acid) glyceryl, ethanol, perfume and colorant.
*other ingredients of Tablet C: MgSO₄, Dry NaSO_4, Soybean oil, PEG(120), polyoxyethylene polyoxpropylene Ethylenediaminetetra, PVP, BHT, perfume and colorant.

(3) Evaluation
(3-1) First discharge test
The cap of the above PET bottle was opened, and 400 mL of water at 30°C was introduced. Then, the above composition was introduced (8 grams for Example 1-1, 1-2, and 1-3; 4 grams for Example 1-4; and 30 grams for Example 1-5), and the PET bottle was sealed with the cap according to Table 3. The bottle was shaken for 30 times by one hand with amplitude of 30 cm, the bottle was opened, and the carbon dioxide-containing aqueous solution was released until the possible last drop in one discharge regardless of the remaining composition in the fluid mixture for another round of discharge. The first discharge was measured its volume and time to determine an average volume flow rate.

(3-2) Clean skin feeling evaluation
The cap of the above PET bottle was opened, and 400 mL of water at 30°C was introduced. Then, the above composition was introduced (8 grams for Example 1-1, 1-2, and 1-3; 4 grams for Example 1-4; and 30 grams for Example 1-5), and the PET bottle was sealed with the cap according to Table 3. The bottle was shaken 30 times by one hand with amplitude of 30 cm, the bottle was opened, and the carbon dioxide-containing aqueous solution was released and applied onto an arm of an expert panelist, then the bottle was resealed and shaken again about a few times and the same application procedure was repeated to complete all content. At the same time, the other arm was poured with water. Five panelists who performed the application as mentioned each performed a sensory evaluation of the clean feeling by touching skin after wiping the arms with a towel according to the five-point scale evaluation criteria shown below. The average value of the scores from the five panelists was determined.
5: Clear clean feeling / Not sticky at all
4: Clean feeling better than application of water alone / Not so sticky
3: Feel not different from application of water alone / Slightly sticky
2: Poorly clean / Sticky
1: Not clean at all / Very sticky

(3-3) Fresh skin feeling evaluation
The cap of the above PET bottle was opened, and 400 mL of water at 30°C was introduced. Then, the above composition was introduced (8 grams for Example 1-1, 1-2, and 1-3; 4 grams for Example 1-4; and 30 grams for Example 1-5), and the PET bottle was sealed with the cap according to Table 3. The bottle was shaken 30 times by one hand with amplitude of 30 cm, the bottle was opened, and the carbon dioxide-containing aqueous solution was released and applied onto an arm of an expert panelist, then the bottle was resealed and shaken again a few times and the same application procedure was repeated to complete all content. At the same time, the other arm was poured with water. Five panelists who performed the application as mentioned each was performed a sensory evaluation of the fresh feeling after wiping the arms with a towel according to the five-point scale evaluation criteria shown below. The average value of the scores from the five panelists was determined.
5: Clear fresh feeling
4: Fresh feeling better than application of water alone
3: Feel not different from application of water alone
2: Hardly fresh
1: Not fresh at all
The results are shown in Table 2. Results of Table 2 show that the method was applicable to various compositions such as Examples No. 1-1, 1-2, and 1-3, and could cause discharges desired by variable mass ratios of carbonate and bicarbonate to the water such as Examples No. 1-1 to 1-5.

By using the formulation, the container and the cap as described above, this method was also applicable to an entire body or a partial body such breast, arms, shoulders, belly, and legs for from 14 seconds to over 1 minutes and imparted cleanness, and freshness.

Example 2

A PET bottle with a cap (bottle port diameter: approximately 2.5 cm; bottle height: approximately 20.5 cm; bottle barrel diameter: appropriately 6.6 cm) in which 123 mL of headspace would be produced when the PET bottle was filled with 400 mL of water was provided. A screw type resealable mechanism and ejection ports were provided in the cap. The ejection ports of the cap were changed as shown in #1, #2 and #3 of Fig. 7, and the ejection state of a fluid mixture from the ejection ports was studied, by using Tablet B in Table 1 (refer to Table 3).

By this operation, regardless of mode of cap, the sweat on the arm was also cleanly washed away, and a further refreshing feeling was obtained.

Example 3

(1) Composition Tablet C in Table 1 was used for this example.
(2) Apparatus
A PET bottle with a cap (bottle port diameter approximately 2.5 cm, bottle height approximately 20.5 cm, bottle barrel diameter 6.6 cm) in which 123 mL of headspace would be produced when the PET bottle was filled with 400 mL of water was provided. Cap #2 in Table 3 was employed. A dip tube was attached to the cap of Example 2-5.

(3) First discharge test
Except that the bottle was shaken varied from 30 to 60 times by one hand with an amplitude of 10 or 30 cm, the test was made in the same manner of Example 1. In Table 4, the "remaining composition in the fluid mixture before discharge" means whether this method was available again by resealing and shaking the bottle after the first discharge.

(4) Clean skin feeling evaluation
Except that the bottle was shaken varied from 30 to 60 times by one hand with an amplitude of 10 or 30 cm, the test was made in the same manner as described in Example 1.

(5) Fresh skin feeling evaluation
Except that the bottle was shaken varied from 30 to 60 times by one hand with an amplitude of 10 or 30 cm, the test was made in the same manner of Example 1.
The conditions and the results are shown in Table 4.
The conditions and their results shown in Table 4 show shaking manners before discharge could cause discharges in different ejection speed and time as desired such as Examples 2-1, 2-2, 2-3, and 2-4, while Example 2-5 shows a possible discharge by presence of dip tube.

By this operation, the sweat on the arms was cleanly washed away, and further a refreshing feeling was obtained. In addition, the skin was slightly tinged with red probably due to the blood circulation promotion effect.

Example 4

(1) Comparative methods for the present invention
Example 2-1 (refer to Table 4) was compared with comparative methods such as (1) a common shower with water alone at the same period of application time and (2) a method of pouring the mixture composition with a common tool (a bucket) at the same volume of fluid mixture, which volume of the present invention was found less than common use of the bucket, by applying the fluid mixture onto the breast, the arms, the shoulders, the belly, and the legs, followed by wiping with a towel.

(2) Evaluation methods
Five respondents performed evaluation of cleansing ability, flexibility during usage, and mobility of the apparatus by means of carrying it from place to place after applying three methods of washing as described above, with respect to superiority as scores ‘A’, ‘B’, and ‘C’, from most to less.
The conditions and the results are shown in Table 5. It is apparent that the invention exerted superior performance over Comparatives (1) and (2).

Claims

A skin washing method comprising the steps of:
(a) mixing water and a composition comprising a carbonate and/or a bicarbonate, and an acid in a container to obtain a fluid mixture, wherein a mass ratio of (i) the total content of the carbonate and the bicarbonate to (ii) the water in the container, [(i)/(ii)], is 0.005 or more and 0.05 or less, and a proportion of the water to an internal volume of the container is 0.3 or more and 0.9 or less;
(b) sealing the container containing the fluid mixture;
(c) making carbon dioxide generated in the container supersaturated; and
(d) releasing the fluid mixture from the container and applying the fluid mixture to a skin.
The skin washing method according to claim 1, wherein the composition further comprises a water-insoluble or hardly water-soluble powder.
The skin washing method according to claim 1 or 2, wherein the composition further comprises a cooling agent, a conditioning agent, essential oil and/or a fragrant agent.
The skin washing method according to any one of claims 1 to 3, wherein the container is a container with a cap configured to be sealable and to be releasable of the fluid mixture in the container, and Step (d) is a step of releasing the fluid mixture via the cap.
The skin washing method according to any one of claims 1 to 4, wherein Step (c) is a step of shaking the container by hand or agitating the fluid mixture.
The skin washing method according to any one of claims 1 to 5, wherein a volume of the water in the container is 300 mL or more and 3 L or less, and the container is made of a resin.
The skin washing method according to any one of claims 4 to 6, wherein the cap has a dip tube having a length reachable at a container bottom.
The skin washing method according to any one of claims 1 to 7, wherein the composition is a solid selected from the group consisting of granule, powder, tablet and briquette.
A skin washing agent kit comprising a container, a cap, and a composition comprising a carbonate and/or a bicarbonate, and an acid.