JP7658728B2 - Liquid skin cleanser - Google Patents

Description

The present invention relates to a liquid skin cleanser filled in a transparent container.

Cleansers for use on the body are required to be mild to the skin, yet have strong cleaning power and produce good foaming and foam quality, and much research is being conducted on these issues.
Recently, there has been a demand for adding value to cleaning agents, and products with beautiful and eye-catching appearances, such as transparent appearances and filling transparent containers, are being considered. On the other hand, because changes in appearance due to storage are noticeable to consumers, studies are also being conducted on ways to suppress such changes in appearance.

For example, Patent Document 1 describes that while soap-based skin cleansers have the problem of precipitating at low temperatures and causing transparent formulations to become cloudy, a soap-based skin cleansing composition that maintains transparency even in a low-temperature environment and has good foam quality, feel after washing, and usability can be obtained by using a combination of an alkylsulfobetaine surfactant, a straight-chain fatty acid alkanolamide surfactant, and a fatty acid and a potassium salt thereof.
Patent Document 2 describes that compositions for scalp and hair containing carotene (vitamin A) and tocopherol (vitamin E) are prone to discoloration and fading due to light, but by blending pyrophosphoric acid, edetic acid, glycolic acid, etc. in specific ratios, discoloration and fading due to light are suppressed and deterioration of appearance can be prevented.
It is also known that fragrances contained in skin cleansers have the problem of discoloration. For example, Patent Document 3 describes that ammonium ions and primary amines in the composition react with carbonyl groups in the fragrance compound and cause discoloration, and therefore, by making a composition that does not contain primary amines or ammonia in a composition that contains a carbonyl-containing fragrance compound, it is possible to obtain a shampoo composition that is substantially colorless for a long period of time, at the same time imparts good cleansing properties and foaming properties, and is mild to the skin.

JP 2017-197453 A JP 2008-273888 A Japanese Patent Application Publication No. 8-501101

The inventors considered filling a transparent skin cleanser into a transparent container in order to create a skin cleanser that is mild to the skin, has excellent cleaning power and foam quality, and has a beautiful appearance that is easily noticeable to consumers; however, the skin cleanser sometimes turns yellow during storage.
The present invention aims to provide a skin cleanser contained in a transparent container, which ensures excellent cleaning power, foaming and foam quality while suppressing discoloration due to light irradiation.

The inventors hypothesized that filling a liquid detergent composition into a transparent container exposed the detergent composition to direct light during storage, causing discoloration of the detergent composition due to the light and the increase in temperature associated with light exposure. After various investigations, they found that problems were likely to arise when trying to achieve the thick, bouncy foam quality characteristic of skin cleansers.
In light of this, we investigated skin cleansing compositions that suppress the progression of discoloration due to light exposure and ensure foam quality, and found that by containing a specific range of nonionic surfactants having a sugar skeleton, and a polyhydric alcohol and a very small amount of a specific colorant, it is possible to obtain a liquid skin cleansing composition that significantly reduces color change due to light exposure, even in a liquid cleansing composition that contains a fragrance, and thus completed the present invention.

The present invention comprises the following components (A), (B), (C), (D) and (E):
(A) an anionic surfactant,
(B) a nonionic surfactant having a sugar skeleton, less than 3% by mass;
(C) a polyhydric alcohol,
(D) 0.000001 to 0.001 mass% of a colorant selected from Yellow No. 4, Yellow No. 5, Yellow No. 205, Yellow No. 401, Yellow No. 402, Yellow No. 404, Yellow No. 405, Yellow No. 406, and Yellow No. 407,
(E) The present invention relates to a liquid skin cleanser comprising a liquid composition containing a fragrance filled in a transparent container.

The liquid skin cleanser of the present invention has excellent cleaning power, foaming and foam quality (easy to spread and thick foam) while suppressing discoloration due to exposure to light.

The anionic surfactant of component (A) used in the present invention may be any that is used in ordinary skin cleansing agents, such as polyoxyalkylene alkyl ether carboxylic acid or its salt, alkyl sulfuric acid or its salt, polyoxyalkylene alkyl ether sulfuric acid or its salt, polyoxyalkylene alkenyl ether sulfuric acid or its salt, sulfosuccinic acid alkyl ester or its salt, polyoxyalkylene sulfosuccinic acid alkyl ester or its salt, α-olefin sulfonic acid or its salt, fatty acid or its salt, N-acylated amino acid or its salt, N-acylalkyltaurine or its salt, etc.

(A1) The polyoxyalkylene alkyl ether carboxylic acid or a salt thereof includes a polyoxyethylene alkyl ether carboxylate represented by the following general formula (1).
R ¹ O(CH ₂ CH ₂ O) _m CH ₂ COOM ¹ (1)
(In the formula, ^R1 represents an alkyl group or alkenyl group having 4 to 22 carbon atoms, m represents the average number of moles added and is a number of 0.5 to 15, and ^M1 represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, or an organic ammonium.)

In general formula (1), from the viewpoints of foaming ability and reduced irritation to stratum corneum cells, ^R1 is preferably an alkyl group having 12 to 16 carbon atoms, and more preferably an alkyl group having 12 to 14 carbon atoms. From the above viewpoints, the average number of moles m of ethylene oxide added is preferably 1 to 10.
Examples of ^M1 include a hydrogen atom, alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium, ammonium, ammonium derived from alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and ammonium derived from basic amino acids such as arginine and lysine. Among these, from the above-mentioned viewpoint, it is preferable to include one or more types selected from sodium, potassium, triethanolamine and arginine, and it is more preferable to include one or two types selected from sodium and potassium.

Specifically, such polyoxyethylene alkyl ether carboxylic acid or a salt thereof preferably includes one or more selected from polyoxyethylene lauryl ether carboxylic acid or a salt thereof, polyoxyethylene myristyl ether carboxylic acid or a salt thereof, and polyoxyethylene palmityl ether carboxylic acid or a salt thereof, more preferably includes one or two selected from polyoxyethylene lauryl ether carboxylic acid or a salt thereof, and polyoxyethylene myristyl ether carboxylic acid or a salt thereof, and even more preferably includes polyoxyethylene lauryl ether carboxylic acid or a salt thereof.
Examples of commercially available products of these include Kaoakipo RLM-45 (manufactured by Kao Corporation), Kaoakipo RLM-45NV (manufactured by Kao Corporation), Kaoakipo RLM-100 (manufactured by Kao Corporation), and Kaoakipo RLM-100NV (manufactured by Kao Corporation).

Examples of the alkyl sulfate or polyoxyalkylene alkyl ether sulfate (A2) include polyoxyethylene alkyl ether sulfate represented by the following general formula (2) or a salt thereof.
R ² O(CH ₂ CH ₂ O) _p SO ₃ M ² (2)
(In the formula, ^R2 represents an aliphatic hydrocarbon group having 8 to 22 carbon atoms, ^M2 represents a cation selected from an alkali metal, an alkaline earth metal, ammonium, an alkylammonium, an alkanolammonium, and a glucammonium, and p represents the average number of moles added and is a number from 0 to 20.)

In general formula (2), from the viewpoint of foaming properties and blend stability, ^R2 is preferably an aliphatic hydrocarbon group having 8 to 18 carbon atoms, more preferably an aliphatic hydrocarbon group having 8 to 16 carbon atoms, and even more preferably an aliphatic hydrocarbon group having 10 to 16 carbon atoms. Furthermore, an alkyl or alkenyl group having 8 to 16 carbon atoms is preferable, an alkyl or alkenyl group having 10 to 16 carbon atoms is more preferable, and an alkyl or alkenyl group having 10 to 14 carbon atoms is even more preferable.
From the viewpoint of foamability, p is preferably from 0.5 to 3.0, and more preferably from 1.0 to 2.0.
From the viewpoint of foaming properties and blend stability, ^M2 is preferably an alkali metal or ammonium, and more preferably contains one or two types selected from sodium and ammonium.

Specific examples thereof include sodium polyoxyethylene (1-2) alkyl ether sulfates such as polyoxyethylene (1) lauryl ether sulfate, polyoxyethylene (1) ammonium lauryl ether sulfate, polyoxyethylene (1) myristyl ether sulfate, polyoxyethylene (2) sodium lauryl ether sulfate, and polyoxyethylene (2) myristyl ether sulfate.
In the present invention, the numerical values in parentheses for these compounds indicate the average number of moles of ethylene oxide added.
Examples of commercially available products of these include EMAL 125HP [manufactured by Kao Corporation, polyoxyethylene (1) lauryl ether sodium sulfate], EMAL 125A [manufactured by Kao Corporation, polyoxyethylene (1) lauryl ether ammonium sulfate], and EMAL 227HP [manufactured by Kao Corporation, polyoxyethylene (2) lauryl ether sodium sulfate].

(A3) The acylated amino acid or its salt may be, for example, the general formula (3)

(wherein ^R3 represents a linear or branched alkyl or alkenyl group having 7 to 21 carbon atoms, ^R4 represents a hydrogen atom or an alkyl or alkenyl group ^having 1 to 4 carbon atoms, R5 represents a hydrogen atom or -( _CH2 ) _qR6 ( ^R6 represents a hydrogen atom, a hydroxyl group or -COOM, and q represents 0 to 3), ^{and M3} represents a hydrogen atom, an alkali metal or an alkanolamine).
Preferred is an N-acylamino acid salt represented by the following formula:

In formula (3), ^R3 is preferably an alkyl group having 6 to 18 carbon atoms, and more preferably an alkyl group having 10 to 16 carbon atoms. ^R4 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. ^R5 is preferably a hydrogen atom or -( _CH2 ) _qR6 . ^M3 is preferably ^an alkali metal.

Specific examples of the N-acylamino acid salt represented by the general formula (3) include N-acylglycine salts such as N-cocoylglycine salt and N-lauroyl-N-methylglycine salt, N-acylglutamate salts such as N-lauroylglutamate and N-myristoylglutamate, N-acylalanine salts such as N-lauroyl-β-alanine salt and N-myristoyl-β-alanine salt, N-acylaspartate salts such as N-lauroylaspartate, N-acylserine salts such as N-lauroylserine salt, and also include alkali metal salts thereof such as sodium and potassium, and alkanolamine salts such as monoethanolamine, diethanolamine, triethanolamine, etc. The compound represented by the general formula (4) may be in the L-form, D-form, or racemic form, and any of these may be used in the present invention.
Of these, N-acylglycine salts and N-acylaspartate salts are preferred.

(A4) The fatty acid or salt thereof includes a fatty acid having 10 to 22 carbon atoms or a salt thereof.
As the fatty acid having 10 to 22 carbon atoms or a salt thereof, from the viewpoints of blend stability and foaming property, those containing a fatty acid having a linear or branched alkyl group having 10 to 18 carbon atoms are preferable, and those containing a fatty acid having a linear alkyl group having 12 to 14 carbon atoms are more preferable.
Specifically, one or more types selected from laurate, myristate, palmitate, stearate, and behenate can be mentioned, and from the above viewpoint, one or two types selected from laurate, myristate, and stearate are more preferable.
These salts preferably contain one or more types selected from alkali metals and ammonium, more preferably contain one or more types selected from alkali metals, and further preferably are sodium salts and potassium salts.

As component (A), from the viewpoints of providing a good feeling when used, reducing irritation to the skin, and providing a mild feeling to the skin, polyoxyethylene alkyl ether carboxylic acid or its salt, and N-acyl amino acid or its salt are preferred.

The anionic surfactant may be contained in the liquid composition as a neutralized salt. The neutralized salt may be any of those mentioned above, but from the viewpoint of further improving storage stability at low temperatures, an alkanolamine salt of component (A) may also be contained. From the viewpoint of suppressing discoloration of the liquid composition due to long-term exposure to light, the content of the alkanolamine salt of component (A) in the liquid composition is preferably less than 0.1% by mass, more preferably 0.05% by mass or less, and even more preferably not contained.

Component (A) may be used alone or in combination of two or more kinds. From the viewpoints of cleaning power and foaming, the content in the liquid composition is preferably 0.1 to 20 mass%, more preferably 0.5 to 16 mass%, and even more preferably 1.0 to 12 mass%. From the viewpoints of suppressing discoloration of the liquid composition due to long-term irradiation with light, the content of component (A) in the liquid composition is preferably 2.5 mass% or more, more preferably 5 mass% or more, and even more preferably 8 mass% or more. From the viewpoints of increasing the visible light transmittance (transmittance at a wavelength of 600 nm) of the liquid composition, the content of component (A) in the liquid composition is preferably 12 mass% or less, more preferably 11 mass% or less, and even more preferably 10 mass% or less.

Component (B) is a nonionic surfactant having a sugar skeleton, and is a component that improves foam quality in combination with component (A).
The sugar skeleton refers to monosaccharides and structures derived from monosaccharides, such as glucoside, sorbitan, and sucrose. Examples of component (B) include (B1) alkyl glucoside, (B2) polyoxyethylene sorbitan fatty acid ester, and (B3) sucrose fatty acid ester.

(B1) As the alkyl glucoside, those used in ordinary cleaning agents, alkyl glucosides having an alkyl group with 8 to 20 carbon atoms are preferred, and from the viewpoints of foaming, foam retention, and low-temperature stability, alkyl glucosides having an alkyl group with 10 to 16 carbon atoms are more preferred.

Component (B1) can be used alone or in combination of two or more kinds. From the viewpoint of suppressing discoloration due to long-term exposure to light, the content in the liquid composition is preferably 1.5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably none.

As the polyoxyethylene sorbitan fatty acid ester (B2), those used in ordinary detergents, which have a fatty acid with an alkyl group having 12 to 22 carbon atoms and a degree of polymerization of ethylene oxide of 10 to 300, are preferred.
From the viewpoints of foam quality, foaming ability and low temperature stability, the component (B2) preferably has an HLB of 10 to 20, and more preferably an HLB of 13 to 20.
Here, the HLB value is an index showing the hydrophilic-lipophilic balance, and in this specification, the value calculated by the following formula by Griffin is used.

Examples of the polyoxyethylene sorbitan fatty acid ester of component (B2) include polyoxyethylene sorbitan coconut oil fatty acid ester, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan myristate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan isostearate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan behenate, polyoxyethylene sorbitan tristearate, and polyoxyethylene triisostearate.
Among these, from the viewpoint of low-temperature stability, the number of carbon atoms in the alkyl group of the fatty acid constituting the polyoxyethylene sorbitan fatty acid ester is preferably 12 to 18, more preferably 12 to 16, and even more preferably 12 to 14. The degree of polymerization of ethylene oxide is preferably 5 to 300, more preferably 10 to 100, and even more preferably 20 to 80.
Furthermore, the polyoxyethylene sorbitan fatty acid ester is preferably a polyoxyethylene mono fatty acid ester.

Component (B) can be used alone or in combination of two or more types. From the viewpoint of suppressing discoloration due to long-term exposure to light, the content in the liquid composition is less than 3 mass %, preferably 2 mass % or less, more preferably 1 mass % or less, and even more preferably none is contained.
On the other hand, from the viewpoint of achieving a better balance between foam quality and discoloration suppression, it is preferable to contain component (B). From the viewpoint of achieving a better balance between foam quality and discoloration suppression, the component (B) contained in the composition is preferably (B2) polyoxyethylene sorbitan fatty acid ester, and from the viewpoint of achieving a higher level of balance between foam quality and discoloration suppression, the content of component (B) in the liquid composition is preferably 0.1 to 3 mass%, more preferably 0.5 to 2 mass%.
From the same viewpoint, the content of the (B1) alkyl glucoside in the liquid composition is preferably 1.5% by mass or less, more preferably 10% by mass or less, and even more preferably 0.5% by mass or less, and the content of the (B2) polyoxyethylene sorbitan fatty acid ester in the liquid composition is preferably 0.5 to 3% by mass, and more preferably 1 to 2% by mass.

The polyhydric alcohol of component (C) used in the present invention is one that is used in ordinary cleaning agents, and examples thereof include dihydric alcohols such as ethylene glycol, diethylene glycol, hexylene glycol, polyethylene glycols having an average molecular weight of 10,000 or less, propylene glycol, 1,3-propanediol, dipropylene glycol, polypropylene glycol, isoprene glycol, and 1,3-butylene glycol; trihydric or higher alcohols such as glycerin, diglycerin, triglycerin, tetraglycerin, hexaglycerin, decaglycerin, and trimethylpropanol; and sugars or sugar alcohols such as erythritol, pentaerythritol, dipentaerythritol, glucose, mannose, galactose, sucrose, fructose, maltose, maltitol, xylitol, inositol, sorbitan, and sorbitol.
Of these, glycerin and polyethylene glycol are preferred from the viewpoints of suppressing discoloration of the composition and sufficiently improving foam quality.

The polyhydric alcohol of component (C) can be used alone or in combination of two or more kinds. The content in the liquid composition is preferably 0.5 to 35% by mass, more preferably 1 to 30% by mass, and even more preferably 2 to 25% by mass, from the viewpoints of suppressing discoloration of the composition and improving foam quality (ease of spreading the foam, feeling of thick foam).

Moreover, from the viewpoint of further improving foam quality, it is preferable that the polyhydric alcohol of component (C) contains (C1) glycerin.
From the viewpoint of further improving foam quality, the content of (C1) glycerin in the liquid composition is preferably 0.5 to 20 mass%, more preferably 3 to 17 mass%, and even more preferably 5 to 15 mass%.

In the present invention, the mass ratio (A)/(C) of component (A) to component (C) is preferably 0.1 to 40, more preferably 0.2 to 20, and even more preferably 0.3 to 10, from the viewpoint of improving the foam quality.

In the present invention, when the liquid composition contains (B2) polyoxyethylene sorbitan fatty acid ester, from the viewpoint of further minimizing the change in color of the composition while maintaining the foam quality, the mass ratio (B2)/(C) of component (B2) to component (C) is preferably 0.01 to 6, and more preferably 0.05 to 2.

Component (D) of the present invention is a colorant selected from Yellow No. 4, Yellow No. 5, Yellow No. 205, Yellow No. 401, Yellow No. 402, Yellow No. 404, Yellow No. 405, Yellow No. 406, and Yellow No. 407. These colorants are azo dyes, and reduce the amount of color change due to light irradiation in the liquid composition of the present invention.
Component (D) can be used alone or in combination of two or more types. From the viewpoint of reducing the amount of change in color of the liquid composition, the content is from 0.000001 to 0.001 mass %, preferably from 0.000005 to 0.001 mass %, and more preferably from 0.00001 to 0.0007 mass %, in the liquid composition.
Furthermore, from the viewpoints of making the color of the liquid composition before light irradiation natural and improving the initial appearance of the product, the content of component (D) in the liquid composition is preferably 0.0005% by mass or less, more preferably 0.003% by mass or less, and even more preferably 0.0001% by mass or less.
The content of component (D) can be analyzed by liquid chromatography/mass spectrometry (LC/MS).
In the present invention, the reason why the inclusion of a small amount of component (D) reduces the amount of color change in the composition is not clear in detail, but it is presumed that since the colorant of component (D) has the property of relatively fading when exposed to light, there is a good balance between the color change due to component (D) and the color change of the skin cleanser composition, and the amount of color change of the skin cleanser composition is kept extremely small even when exposed to light for a long period of time.

The liquid skin cleansing agent of the present invention contains a fragrance (E) in the liquid composition to improve the scent.
The fragrance used in the present invention may be a single fragrance component or a fragrance composition containing a plurality of fragrance components.
The aroma component is not particularly limited, and examples of the aroma component include synthetic fragrances described in "Perfume and Flavor Chemicals" edited by Steffen Arctander, Montclair, NJ (USA) (1969), "Synthetic Fragrances - Chemistry and Product Knowledge" edited by the Synthetic Fragrances Editorial Committee (The Chemical Daily, December 20, 2016, revised and expanded edition), and "Basic Knowledge of Fragrances and Fragrances" edited by Nakajima Mototaka, Sangyo Tosho (first edition, 1995), as well as natural fragrances such as plant extracts.

From the viewpoint of improving the fragrance, the content of component (E) in the liquid composition is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and even more preferably 0.05% by mass or more. From the viewpoint of suppressing discoloration due to long-term irradiation with light, the content of component (E) in the liquid composition is preferably 1% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less.
Furthermore, from the viewpoint of suppressing discoloration due to exposure to light for a long period of time, it is preferable that the fragrance does not contain a large amount of plant extract; specifically, the content of plant extract in the liquid composition is preferably less than 0.001% by mass, more preferably 0.0008% by mass or less, even more preferably 0.0005% by mass or less, and even more preferably none.

In the present invention, from the viewpoint of improving the fragrance of the skin cleanser while further reducing the amount of change in color of the composition, the mass ratio (E)/(D) of component (E) to component (D) is preferably 15 to 900,000, more preferably 20 to 300,000, and even more preferably 200 to 70,000.

In the present invention, from the viewpoint of improving the fragrance and foam quality of the skin cleanser while further reducing the amount of change in color of the composition, the mass ratio ((B)+(E))/(D) of the total amount of components (B) and (E) to component (D) is preferably 3,000 to 2,500,000, more preferably 10,000 to 500,000, and even more preferably 20,000 to 200,000.

In the present invention, the liquid composition may contain surfactants other than components (A) and (B), but from the viewpoint of suppressing discoloration caused by exposure of the skin cleanser to light, it is preferable that the content of alkylamine oxide is small. The content of alkylamine oxide in the liquid composition is preferably less than 3% by mass, more preferably 1% by mass or less, and even more preferably no alkylamine oxide is contained.

In addition, in the present invention, from the viewpoint of suppressing discoloration caused by exposure of the skin cleanser to light, it is preferable that the content of the cationic polymer in the liquid composition is small. The content of the cationic polymer in the liquid composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, even more preferably 0.1% or less, and even more preferably no cationic polymer is contained.

In the present invention, in addition to the above-mentioned components, the liquid composition may contain components used in ordinary cleaning compositions, provided that the effects of the present invention are not impaired. For example, surfactants other than those mentioned above; lower alcohols such as ethanol and isopropyl alcohol; aromatic alcohols such as benzyl alcohol and benzyloxyethanol; cellosolves such as ethyl cellosolve and butyl cellosolve; carbitols such as ethyl carbitol and butyl carbitol; moisturizing ingredients such as sugar (derivatives), amino acid (derivatives), animal and plant (protein) derivatives, and animal and plant extracts; silicone derivatives such as polyoxyalkylene-modified silicone; inorganic or organic salts such as sodium sulfate, sodium carbonate, sodium bicarbonate, potassium chloride, sodium chloride, and sodium citrate; pH adjusters such as acids and alkalis; anti-inflammatory agents such as glycyrrhizic acid, glycyrrhizic acid and derivatives thereof; bactericides such as isopropylmethylphenol; preservatives, sequestering agents, antioxidants, ultraviolet absorbers, anionic polymers, nonionic polymers, amphoteric polymers, fragrances, thickeners, vitamins, natural dyes, tar dyes, and other colorants other than those mentioned above.

In the present invention, the liquid composition is in the form of a liquid in which the above-mentioned components are dissolved in water.
The content of water is the balance of the above components and other components contained as necessary, and is preferably 40 to 75 mass %, more preferably 45 to 70 mass %, and even more preferably 50 to 65 mass % in the liquid composition.

In the present invention, it is preferable that the liquid composition is not excessively colored from the viewpoint of the beauty of the appearance. Here, the liquid composition in the present invention refers to one having a Hazen color number of preferably 100 or less, more preferably 75 or less, even more preferably 50 or less, and 0 or more. The Hazen color number is a value determined according to the method defined in JIS K0071-1:2017.

In the present invention, the liquid composition is preferably transparent. Here, transparency means that the transmittance at a wavelength of 600 nm is 10% or more, preferably 40% or more, more preferably 70% or more, and 100% or less. The transmittance can be measured by the measurement method described in the examples below.

The liquid skin cleansing agent of the present invention is prepared by filling the liquid composition obtained as described above into a transparent container.
The container is preferably a foamer container that is mixed with air and discharged as foam, particularly a non-gas foamer container. When filling the foamer container, the viscosity of the liquid composition is preferably 1 to 20 mPa·s, more preferably 2 to 15 mPa·s, even more preferably 3 to 13 mPa·s, and even more preferably 5 to 11 mPa·s at 30° C., from the viewpoint of forming a fine and thick foam, since the composition before filling the container is in a liquid state.
In the present invention, the viscosity is measured at 30° C. using a Brookfield viscometer (Toki Sangyo, TVB-10) with a No. 1 rotor at a rotation speed of 60 r/min, and the viscosity is measured 60 seconds after the start of rotation.
Even with a liquid composition having such a low viscosity, discoloration is sufficiently suppressed, and a cleaning agent having excellent foam quality and foaming properties can be realized.

The liquid composition is filled in a transparent container.
In the present invention, the term "transparent" in the context of a transparent container means that the container is transparent to visible light, and specifically means that the transmittance at 600 nm is 10% or more, preferably 40% or more, more preferably 70% or more, and 100% or less. The transmittance of visible light can be measured in accordance with JIS K7375:2008.
In the present invention, a transparent container means that at least the upper 30% of the container is "transparent" as described above, it is more preferable that the upper half of the container is transparent, and it is even more preferable that the entire container is transparent.

Any foamer container can be used as long as it can be mixed with air and discharged as foam, for example, a pump foamer container that discharges by pressing a pump head, or a squeeze foamer container that discharges by pressing a body part can be mentioned, and specific examples include foamer containers manufactured by Yoshino Kogyosho Co., Ltd., Yamato Can Co., Ltd., and Rieke Co., Ltd. Also, for example, foamer containers described in JP-A-7-315463, JP-A-8-230961, JP-A-2005-193972, etc. can be used.
Among them, from the viewpoint of convenience in the environment in which the liquid detergent is used, a pump foamer container that discharges by pressing the pump head is preferred, and from the viewpoint of further improving the foam quality, a container equipped with a porous membrane filter in the discharge flow path is preferred. From the viewpoint of obtaining finer and better foam quality, such a porous membrane filter is preferably a 50 to 500 mesh filter, more preferably a 100 to 400 mesh filter, even more preferably a 200 to 400 mesh filter, and even more preferably a 200 to 305 mesh filter. It is preferable to place 1 to 3 such porous filters in the discharge flow path. In addition, examples of preferred materials for the mesh of such filters include nylon and polyester.
The mixture ratio of the liquid composition to air in the pump foamer container is preferably 0.03 to 0.14 g/cm3, and more preferably 0.05 to 0.11 g/ ^cm3 , from the viewpoint of obtaining a foam quality that produces good foam and allows easy washing of the skin, in terms of the density of the foam to be discharged (mass of liquid composition/volume of air ⁾ .

The liquid skin cleansing agent of the present invention is preferably used for skin cleansing, and more preferably used as hand soap, face wash, or body soap.The liquid skin cleansing agent of the present invention can be used to cleanse the skin by a general skin cleansing method.For example, when filled in a foamer container, the foam discharged from the container can be taken by hand, directly applied to the skin without diluting with water, foamed and cleansed, and then rinsed with warm water such as a shower.
The washing method may be by hand or by using a sponge, towel, scrubbing brush, etc. made of chemical fibers such as cotton or nylon. To reduce irritation to the skin, the product may be directly washed by hand, or from the viewpoint of effectively and fully exerting the foaming performance and usability of the present invention, it may be washed with a soft cotton towel, etc.

Examples 1 to 33, Comparative Examples 1 to 2
Liquid compositions having the compositions shown in Tables 1 to 4 were produced by mixing and dissolving each component in water, and the pH was adjusted to 6.2 with citric acid. (The numbers in the tables for the blend amounts indicate the blend amounts of the raw materials unless otherwise specified.) The obtained liquid compositions were placed in a cell with an optical path length of 10 mm, and the transmittance at a wavelength of 600 nm was measured using a photoelectric colorimeter AP-120 (manufactured by APEL Co., Ltd.). The transmittance of each composition was 70% or more (the transmittance (%) at 600 nm is shown in the table). The viscosity of the liquid compositions at 30° C. was also measured using a Brookfield viscometer (Toki Sangyo, TVB-10) with rotor No. 1 at a rotation speed of 60 r/min. The results are shown in Tables 1 to 4.
The obtained liquid composition was filled into a pump former container (a transparent pump former container manufactured by Yoshino Kogyosho Co., Ltd. (the mesh sizes of the porous membrane filters provided in the discharge path were two pieces of 200 mesh and one piece of 305 mesh); a container with a transmittance of 90% at 600 nm) to obtain a liquid skin cleanser in a transparent former container.
The obtained liquid skin cleansing agents in transparent foam containers were stored in their containers at 50° C. for one month or exposed to light, and the change in Hazen color index before and after storage was measured. The results are shown in Tables 1 to 4.
The exposure storage was performed by irradiating light for 240 hours using a Weather-O-Meter Ci4000 (manufactured by Atlas Co., Ltd.). The Hazen color index was calculated by placing each composition in a measurement cell (optical path length 50 mm) and using a spectrophotometer TZ7700 (manufactured by Nippon Denshoku Industries Co., Ltd.) according to the method of JIS K0071-1:2017.

Furthermore, the foam quality (ease of spreading foam, foam thickness) and foaming were evaluated for the liquid skin cleansing agent in the transparent foamer container of the embodiment shown in Table 5. The evaluation results are shown in Table 5.

(Evaluation Method)
(1) Ease of spreading foam:
Five expert panelists wet both arms with water, dispensed foam (liquid volume: 1 mL) onto the palm of one hand, pressed it against the other forearm and massaged it. The panelists evaluated whether the foam felt smooth and easy to spread, based on the following criteria. The results are shown as the average score of the five panelists.
4 points: The foam is slippery.
3 points: The foam is a little slippery.
2 points: The foam is not very slippery.
1 point: The foam is not slippery.

(2) Foam thickness:
Five expert panelists wet both arms with water, dispensed foam (volume: 1 mL) onto the palm of one hand, pressed it against the other forearm and massaged it. The thickness of the foam felt (presence) was evaluated according to the following criteria. The results are shown as the average score of the five panelists.
4 points: Thick.
3 points: Somewhat thick.
2 points: slightly thin.
1 point: No thickness.

(3) Foaming:
Five expert panelists wet both arms with water, dispensed a foam onto the palm of one hand (liquid volume: 1 mL), and spread it onto the other forearm. The panelists assessed whether they felt the foam increase in proportion to the number of times they rubbed the palm together, according to the following criteria. The results are shown as the average score of the five panelists.
4 points: It feels like the bubbles are increasing.
3 points: It feels like the bubbles are increasing slightly.
2 points: It feels like the foam is not increasing.
1 point: I feel like the bubbles aren't increasing

Claims (8)

The following components (A), (B), (C), (D) and (E):
(A) one or more anionic surfactants selected from polyoxyalkylene alkyl ether carboxylic acids or salts thereof, polyoxyalkylene alkyl ether sulfates, and acylated amino acids or salts thereof;
(B ) a nonionic surfactant having a sugar skeleton, less than 3% by mass;
(C) a polyhydric alcohol,
(D) 0.000001 to 0.001% by mass of a colorant selected from Yellow No. 4, Yellow No. 5, Yellow No. 205, Yellow No. 401, Yellow No. 402, Yellow No. 404, Yellow No. 405, Yellow No. 406, and Yellow No. 407,
(E) A liquid skin cleanser comprising a liquid composition containing a fragrance filled in a transparent container. The liquid skin cleanser according to claim 1, wherein the content of (B1) alkyl glucoside in the liquid composition is 1.5% by mass or less. The liquid skin cleanser according to claim 1 or 2, wherein the content of the alkanolamine salt of component (A) in the liquid composition is less than 0.1% by mass. The liquid skin cleanser according to any one of claims 1 to 3, wherein the content of the alkylamine oxide in the liquid composition is less than 3% by mass. The liquid skin cleanser according to any one of claims 1 to 4, wherein the mass ratio (E)/(D) of component (E) to component (D) is 15 to 900,000. The liquid skin cleanser according to any one of claims 1 to 5, wherein the liquid composition has a transmittance of 10 to 100% at a wavelength of 600 nm. The liquid skin cleanser according to any one of claims 1 to 6, wherein the content of (C1) glycerin in the liquid composition is 0.5 to 20 mass%. The liquid skin cleanser according to any one of claims 1 to 7, wherein the mass ratio (A)/(C) of component (A) to component (C) is 0.1 to 40.