JP7643171B2 - Warm skin cleanser - Google Patents

Description

The present invention relates to a warming skin cleanser that gives a warming sensation when used.

Skin cleansers are used to wash away sweat, sebum, dead skin cells, etc. from the face and body, and to keep the skin healthy. There are a variety of skin cleansers on the market, including liquid, gel, foam, and paste. Many highly functional facial cleansers in particular have been developed, and one distinctive example is the warming cleanser, which gives a warm sensation when used. This provides a comfortable warm sensation when applied to the skin, opens pores to make it easier to remove dirt, and is also expected to have the effect of promoting blood flow to the skin.

Conventionally, warming cleansers have been studied to utilize the heat of hydration of minerals such as zeolite and polyhydric alcohols such as glycerin, and to enhance the usefulness of the preparation by combining other ingredients. For example, a hot cleansing agent that combines polyhydric alcohols such as glycerin with a specific glycerin derivative and a nonionic surfactant to provide a good warming sensation, cleansing properties, and post-cleaning feel (Patent Document 1), a keratin plug removal cosmetic that combines a polyhydric alcohol such as glycerin, a polyhydric alcohol fatty acid ester, and a scrub agent (Patent Document 2), a gel-type skin cleanser that combines a polyhydric alcohol such as glycerin, a specific nonionic surfactant, and a specific thickener to have moderate viscosity and excellent cleansing and cleansing properties (Patent Document 3), and a warming skin cosmetic that combines a hydration heat generating inorganic powder, a cationic polymer, an oil component, a nonionic surfactant, and a nonaqueous medium (Patent Document 4) have been disclosed. However, all of these compositions were insufficient in terms of the sustained warming effect.

For example, a warming gel cosmetic composition combining glycerin and polyethylene glycol has been disclosed for the purpose of providing a sustained warming effect (Patent Document 5). However, the refreshing feeling upon washing and the effect on the skin before and after washing were insufficient.
Furthermore, there has been a demand for warming cleansers with a texture that allows for easier, uniform application in order to enhance the warming effect.
Therefore, there is a demand for a warm-feeling skin cleanser that has a texture that allows easy application of a thick, uniform coating to the skin, has a viscosity that prevents the skin from dripping after application, provides a sustained, moderate warmth upon application, and is non-sticky and can thoroughly wash away dirt from the skin.

JP 2007-269719 A JP 2019-14671 A JP 2014-37404 A JP 2009-67721 A JP 2011-116726 A

The object of the present invention is to provide a warming skin cleanser that has a texture that is easy to apply evenly and thickly, has a viscosity that does not drip easily on the skin, provides a moderate lasting warmth, and leaves the skin feeling refreshed when washed off.

In order to solve the above problems, the inventors conducted extensive research and discovered that a warm-feeling skin cleanser that can achieve the above-mentioned objectives can be obtained by combining a polyhydric alcohol containing glycerin, a specific glycerin derivative, a specific nonionic surfactant, an acrylic acid-based thickening polymer, and a specific copolymer in a specific ratio, which led to the completion of the present invention.

That is, the present invention relates to a polyhydric alcohol (A) that is composed of glycerin (A1) and a dihydric alcohol (A2) and has a mass ratio (A1/A2) of 99/1 to 90/10,
0.1 to 10% by mass of an alkylene oxide adduct derivative (B) of glycerin represented by formula (I),
0.5 to 8 mass% of a nonionic surfactant (C) having an HLB of 10 to 16 and selected from polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol ,
0.1 to 0.7% by mass of an acrylic acid-based thickening polymer (D),
0.005 to 0.25% by mass of a copolymer (E) containing structural units represented by the following formulas (II) and (III):
It is a warm-feeling skin cleanser that contains

Gly-[O{(PO) _a (EO) _b }-(BO) _c H] ₃ Formula (I)
(In formula (I), Gly is a residue obtained by removing a hydroxyl group from glycerin, PO is an oxypropylene group, EO is an oxyethylene group, BO is an oxybutylene group, a, b and c are the average molar numbers of PO, EO and BO added, respectively, a+b is 1 to 30, c is 1 to 5, the addition form of PO and EO may be random or block, and the mass ratio of PO/EO is 1/5 to 5/1.)

（式（II）中、Ｒ^１は水素原子またはメチル基を示す。）

(In formula (II), R ¹ represents a hydrogen atom or a methyl group.)

（式（III）中、Ｒ^２は水素原子またはメチル基を示し、ｍは３～１８の整数を示す。）

(In formula (III), ^R2 represents a hydrogen atom or a methyl group, and m represents an integer of 3 to 18.)

The warming skin cleanser of the present invention has a texture that allows easy application of a thick, uniform coating, has a viscosity that prevents it from dripping off the skin, maintains a moderate warmth, and leaves the skin feeling refreshed when washed off. Thus, the warming skin cleanser of the present invention can be expected to, for example, open pores to make it easier to remove dirt while providing a comfortable warmth when applied to the skin, and also promote blood flow to the skin.

In this specification, the term "warm sensation" refers to a sensation of warmth felt when the cleansing agent of the present invention is applied to the skin. The mechanism of the warming sensation caused by the warming skin cleansing agent of the present invention is not particularly limited, but for example, the polyhydric alcohol (A), particularly glycerin (A1), reacts with moisture in the skin to generate heat of hydration, resulting in a warming sensation.
The warm-feeling skin cleanser of the present invention can be used not only for cleaning the skin but also for cleaning the skin. In this specification, "skin" refers to human skin, particularly facial skin, and "skin" refers to the body surface of the head, neck, torso, arms, and legs including the face.

Hereinafter, an embodiment of the present invention will be described.
In this specification, the numerical ranges defined using the symbol "to" are intended to include both the upper and lower limits of the symbol "to". For example, "2 to 5" means 2 or more and 5 or less.

The warm-feeling skin cleanser of the present invention (hereinafter also simply referred to as "cleanser") contains at least a polyhydric alcohol (A), an alkylene oxide adduct derivative of glycerin (B), a nonionic surfactant (C), an acrylic acid-based thickening polymer (D), and a copolymer (E). Each component is described below.

[Polyhydric alcohol (A)]
The polyhydric alcohol (A) used in the cleansing agent of the present invention consists of glycerin (A1) and a dihydric alcohol (A2), and can impart a sustained warm sensation upon application, moderate viscosity, and the effect of conditioning the skin to a healthy skin tone after cleansing.

The dihydric alcohol (A2) may, for example, be a dihydric alcohol having 3 to 8 carbon atoms. Specific examples of dihydric alcohols having 3 to 8 carbon atoms include propylene glycol, butylene glycol, diethylene glycol, pentylene glycol, hexylene glycol, dipropylene glycol, heptylene glycol, and octylene glycol. Among these, in terms of the refreshing feeling after washing, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,2-pentylene glycol, and dipropylene glycol are preferred, and 1,3-butylene glycol is more preferred. One or more of these dihydric alcohols (A2) may be used.

The polyhydric alcohol (A) has a mass ratio (A1/A2) of glycerin (A1) to dihydric alcohol (A2) of 99/1 to 90/10, preferably 98/2 to 92/8, more preferably 97/3 to 93/7, and particularly preferably 96/4 to 94/6.
If the ratio of the dihydric alcohol (A2) is too high, it may be difficult to obtain a sustained warm sensation, and if the ratio of the dihydric alcohol (A2) is too low, it may be difficult to obtain an appropriate viscosity, and the resistance to dripping on the skin may be reduced.

The content of polyhydric alcohol (A) is 75 to 95% by mass, preferably 80 to 92% by mass, and more preferably 85 to 90% by mass, of the total amount of the cleanser. If the content is too low, it may be difficult to apply thickly, which may impair the sustained warmth and resistance to dripping off the skin, while if the content is too high, the warmth may be felt too strongly, which may cause irritation, and the refreshing feeling during cleansing may be reduced.

[Alkylene oxide addition derivatives of glycerin (B)]
The alkylene oxide adduct of glycerin (B) used in the cleansing agent of the present invention is a glycerin derivative represented by the following formula (I).
Gly-[O{(PO) _a (EO) _b }-(BO) _c H] ₃ Formula (I)

In formula (I), Gly represents a residue obtained by removing a hydroxyl group from glycerin.
The oxypropylene group represented by PO and the oxybutylene group represented by BO may be either linear or branched, but are preferably oxypropylene and oxybutylene groups obtained from propylene oxide (1,2-epoxypropane) and 1,2-butylene oxide, respectively.
In formula (I), for the oxypropylene group represented by PO and the oxyethylene group represented by EO, the sum (a+b) of the average number of moles added per one hydroxyl group of glycerin is 1 to 30, preferably 2 to 20, and more preferably 3 to 10. For the oxybutylene group represented by BO, the average number of moles added c per one hydroxyl group of glycerin is 1 to 5, preferably 1 to 3, and more preferably 1 to 2.

In the alkylene oxide addition derivative of glycerin represented by formula (I), the content ratio (PO/EO) of the oxypropylene group represented by PO to the oxyethylene group represented by EO is 1/5 to 5/1, preferably 1/2 to 4/1, and more preferably 1/2 to 3/1, in terms of mass ratio.
The oxypropylene and oxyethylene groups may be added to the hydroxyl groups of glycerin in either a random or block form, but in order to obtain a high penetration feeling, it is preferable that they are added in a random form. The oxybutylene groups are added to the terminals of the alkylene oxide chains in a block form.

The alkylene oxide addition derivative of glycerin represented by formula (I) can be appropriately synthesized by a known alkylene oxide addition reaction and used, but a commercially available product such as "WILBRIDE (registered trademark) S-753" (in formula (I), a+b=4.3, c=1, and the mass ratio of PO to EO (PO/EO)=4/5) provided by NOF Corporation can also be used.

The content of the alkylene oxide adduct derivative (B) of glycerin is 0.1 to 10% by mass, preferably 0.5 to 8% by mass, and more preferably 1 to 6% by mass, based on the total amount of the cleansing agent. If the content is too low, the refreshing feeling during cleansing may decrease. If the content is too high, the ease of applying a uniform thick coat may be impaired, and the sustained warming effect may be impaired.
The alkylene oxide adduct derivatives of glycerin (B) may be used alone or in combination of two or more.

[Nonionic Surfactant (C)]
The nonionic surfactant (C) used in the cleansing agent of the present invention is one or more nonionic surfactants selected from polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol , and has an HLB (hydrophile-lipophile balance) of 10 to 16.

HLB is expressed as IOB value in the organic conceptual diagram x 10. The IOB value in the organic conceptual diagram refers to the ratio of inorganic value (IV) to organic value (OV) in the organic conceptual diagram, i.e., "inorganic value (IV)/organic value (OV)". The organic conceptual diagram was proposed by Fujita Atsushi, and its details are explained in "Pharmaceutical Bulletin", 1954, vol. 2, 2, pp. 163-173; "Chemical Domain", 1957, vol. 11, 10, pp. 719-725; "Fragrance Journal", 1981, vol. 50, pp. 79-82, etc.

If the HLB is too low, the solubility in water decreases, the washability decreases, and the product may feel sticky when applied. If the HLB is too high, the cleaning power decreases and the product may become dry after rinsing with water. From this perspective, it is preferable that the HLB of the nonionic surfactant (C) is 10 to 15.

The fatty acid in the polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol may be a straight-chain or branched fatty acid having 8 to 22 carbon atoms, preferably 8 to 18 carbon atoms. Specific examples include saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, etc.; unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, etc.; and mixed fatty acids such as caprylic acid/capric acid, coconut oil fatty acid, palm kernel oil fatty acid, etc.
The average number of moles of ethylene oxide added in the polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol is preferably 4 to 50, more preferably 5 to 40, and even more preferably 6 to 35. If the average number of moles added is too small, blending may become difficult, and if the average number of moles added is too large, cleaning power may decrease. The number of esters is preferably 1 to 6, and more preferably 1 to 4.

Specific examples of polyoxyethylene fatty acid glyceryl include PEG-7 coconut oil fatty acid glyceryl, PEG-8 (caprylic acid/capric acid) glyceryl, and PEG-30 glyceryl cocoate.
Specific examples of polyoxyethylene fatty acid sorbitol include sorbeth-30 tetraoleate and sorbeth-30 tetraisostearate.

As the nonionic surfactant (C), one or more selected from polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol can be used, but from the viewpoint of cleaning properties, it is preferable to use two or more of them in combination.

The content of the nonionic surfactant (C) is 0.5 to 8% by mass, preferably 1 to 6% by mass, and more preferably 2 to 5% by mass, of the total amount of the cleanser. If the content is too low, the refreshing feeling during cleansing may decrease. If the content is too high, the sustained warm feeling may be impaired.

[Acrylic acid-based thickening polymer (D)]
The acrylic acid-based thickening polymer used in the present invention is a carboxyvinyl polymer or an alkyl-modified carboxyvinyl polymer. Here, the carboxyvinyl polymer is a polymer of mainly acrylic acid crosslinked with allyl sucrose or allyl ether of pentaerythritol. The alkyl-modified carboxyvinyl polymer is a copolymer of acrylic acid or methacrylic acid and alkyl acrylate or alkyl methacrylate.

Specific examples of such products include carboxyvinyl polymers such as "AQUPEC HV-505E" manufactured by Sumitomo Seika Chemicals Co., Ltd., "Carbopol Ultrez 10 Polymer,""Carbopol940," and "Carbopol 941" manufactured by The Lubrizol Corporation, and "Syntharen K" and "Syntharen L" manufactured by 3V Sigma, and examples of such alkyl-modified carboxyvinyl polymers include "AQUPEC HV-501ER" manufactured by Sumitomo Seika Chemicals Co., Ltd., and "Carbopol 1342" and "Carbopol ETD2020" manufactured by The Lubrizol Corporation.
The carboxyvinyl polymer and the alkyl-modified carboxyvinyl polymer may each be used alone or in combination of two or more kinds.

The content of the acrylic acid-based thickening polymer (D) is 0.1 to 0.7% by mass, preferably 0.2 to 0.6% by mass, and more preferably 0.3 to 0.5% by mass, of the total amount of the cleanser. If the content is too low, the ease of thick application, the resistance to dripping during application, and the sustained warmth may be impaired. If the content is too high, the refreshing feeling during rinsing may be reduced, and it may become difficult to apply evenly, reducing each effect.

[Copolymer (E)]
The copolymer (E) used in the cleansing agent of the present invention contains the constituent units represented by the following formulae (II) and (III).

（式（II）中、Ｒ^１は水素原子またはメチル基を示す。）

(In formula (II), R ¹ represents a hydrogen atom or a methyl group.)

（式（III）中、Ｒ^２は水素原子またはメチル基を示し、ｍは３～１８の整数を示す。）

(In formula (III), ^R2 represents a hydrogen atom or a methyl group, and m represents an integer of 3 to 18.)

The structural unit represented by the above formula (II) is a structural unit based on 2-(meth)acryloyloxyethyl phosphorylcholine, where (meth)acryloyl means acryloyl or methacryloyl.
The structural unit represented by the above formula (III) is a structural unit based on alkyl (meth)acrylate.
The alkyl group in the alkyl (meth)acrylate is a linear or branched alkyl group having 4 to 19 carbon atoms, and examples thereof include butyl, pentyl, hexyl, octyl, 2-ethylhexyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, etc. Of these, linear alkyl groups such as butyl, dodecyl, octadecyl, etc. are preferred, and butyl and octadecyl (stearyl) are more preferred.
If the number of carbon atoms in the alkyl group is too small, the uniform thick coating property may decrease, which may reduce the effect of the present invention, whereas if the number of carbon atoms in the alkyl group is too large, it may become difficult to dissolve the composition in water or an aqueous solvent.

The ratio of the contents of the structural unit represented by formula (II) above and the structural unit represented by formula (III) above in copolymer (E) ([structural unit represented by formula (II)]:[structural unit represented by formula (III)]) (n1:n2) is, in molar ratio, preferably 10:1 to 1:4, more preferably 5:1 to 1:3, and particularly preferably 5:1 to 1:2.
If the ratio (n2/n1) (molar ratio) of the content of the structural unit represented by formula (III) to the content of the structural unit represented by formula (II) is too small, the uniformity of the coating may be impaired when applying a thick coating, whereas if the content ratio (n2/n1) is too large, the solubility of the copolymer (E) in the composition of the present invention may decrease.

The weight average molecular weight of the copolymer (E) is usually from 10,000 to 1,000,000, preferably from 30,000 to 900,000, and more preferably from 50,000 to 800,000.
If the weight average molecular weight of the copolymer (E) is too low, the uniformity of thick coating may be impaired, whereas if the weight average molecular weight of the copolymer (E) is too high, handling may become difficult.
The weight average molecular weight of the copolymer (E) is measured by gel permeation chromatography (GPC) and is expressed as a molecular weight converted into polyethylene glycol.

The polymerization form of the copolymer (E) is not particularly limited, and may be a random copolymer or a block copolymer, with a random copolymer being preferred.
Furthermore, the copolymer (E) is usually a binary copolymer consisting of a structural unit represented by the above formula (II) and a structural unit represented by the above formula (III), but it may also be a copolymer containing other structural units in addition to the structural units represented by formulas (II) and (III).
Other structural units that can be included in the copolymer (E) can be appropriately selected from those that can be structural units of the copolymer, as long as they do not impede the effects of the present invention. Examples of monomers that form other structural units include (meth)acrylic acid esters having a lower alkyl group with 1 to 3 carbon atoms, such as methyl (meth)acrylate and ethyl (meth)acrylate; (meth)acrylic acid esters having a cyclic alkyl group, such as cyclohexyl (meth)acrylate; (meth)acrylic acid esters containing an aromatic group, such as benzyl (meth)acrylate and phenoxyethyl (meth)acrylate; styrene-based monomers, such as styrene, methylstyrene, and chloromethylstyrene; vinyl ether-based monomers, such as methyl vinyl ether and butyl vinyl ether; vinyl ester-based monomers, such as vinyl acetate and vinyl propionate.
These other structural units may be contained in one or more types, and the content thereof in the copolymer (E) is preferably 40 mol % or less, more preferably 20 mol % or less, based on the total amount of the structural units represented by formulas (II) and (III).

The copolymer (E) can be produced by a production method known per se.
For example, it can be produced by polymerizing a monomer mixture containing 2-(meth)acryloyloxyethyl phosphorylcholine, alkyl (meth)acrylate, and, as necessary, monomers that form the other structural units described above, in the presence of a radical polymerization initiator and under an inert gas atmosphere such as nitrogen, by a known method such as solution polymerization.
In this case, the content ratio of each monomer is preferably adjusted to a ratio corresponding to the content ratio of each structural unit in copolymer (E).
Moreover, a commercially available product can also be used as the copolymer (E), for example, "Lipidure (registered trademark)-PMB" manufactured by NOF Corporation can also be used.

The content of copolymer (E) is 0.005 to 0.25% by mass, preferably 0.01 to 0.2% by mass, and more preferably 0.025 to 0.1% by mass, based on the total amount of the cleanser. If the content is too low, the ease of thick application, the resistance to dripping during application, and the sustained warmth may be impaired, while if the content is too high, it may be difficult to apply evenly, which may reduce the effects of the present invention.

[Medium]
The cleansing agent of the present invention may contain water and/or an organic solvent as a medium, and preferably contains water from the viewpoint of solubility of other components and economic efficiency. Examples of the organic solvent include lower alkanols such as ethanol, and aromatic alcohols such as benzyl alcohol, and one selected from these organic solvents may be used alone, or two or more may be used in combination.

The content of the medium is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, and even more preferably 3 to 6% by mass, of the total amount of the cleanser. The above content of the medium includes the amount of the medium contained in the above components (A) to (E), the amount of the medium used when mixing these components (A) to (E), and the amount of the medium used when adjusting the total amount of the cleanser.

[Scrubbing agent]
The warm-feeling skin cleanser of the present invention may contain a scrubbing agent, which can further enhance the effects of the present invention.
Examples of scrubbing agents include polysaccharides such as glucomannan, modified starch, crystalline cellulose, and lactose; hydrocarbon polymer compounds such as polyethylene, polypropylene, and polystyrene; polyamide polymer compounds such as nylon; plant leaf, root, fruit, stem, and other derivatives such as peach kernel powder, apricot kernel powder, walnut shell powder, almond shell powder, hazel shell powder, olive kernel powder, apricot kernel powder, and cherry kernel powder; seawater-dried products such as sea salt; and resins such as candelilla wax and hydrogenated jojoba wax. One selected from these may be used alone, or two or more may be used in combination.
When the warm-feeling skin cleanser of the present invention is used as a facial cleanser, it is preferable to use a scrubbing agent that is low in hardness and puts less strain on the skin, and for example, glucomannan and corn-derived sodium acrylate grafted starch are suitably used.
When the cleansing agent of the present invention contains a scrubbing agent, the content of the scrubbing agent in the total amount of the cleansing agent is preferably 0.01 to 10 mass %, more preferably 0.1 to 5 mass %, and particularly preferably 0.5 to 3 mass %.

[Other ingredients]
In addition to the above-mentioned components (A) to (E), medium and scrubbing agent, the warm-feeling skin cleanser of the present invention may contain one or more other ingredients generally contained in skin cleansers, provided that the effects of the present invention are not impaired.
Examples of such other components include silicone derivatives such as highly polymerized dimethylpolysiloxane, polyether-modified dimethylpolysiloxane, and amino-modified dimethylpolysiloxane; oily bases such as ceramide, cholesterol, protein derivatives, lanolin, lanolin derivatives, and lecithin; amphoteric surfactants such as amide amino acid salts and amidopropyldimethylaminoacetate betaine; nonionic surfactants (excluding the nonionic surfactant (C)) such as polyoxyethylene alkyl ethers, fatty acid esters of polyethylene glycol, polyoxyethylene hydrogenated castor oil, polyglycerin fatty acid esters, glycerin monofatty acid esters, alkyl polyglucosides, and alkanolamides; cationic surfactants such as alkyltrimethylammonium chloride; semi-polar surfactants such as alkyldimethylamine oxide; acids and alkalis as pH adjusters; disinfectants; chelating agents; antioxidants; blood circulation promoters; ultraviolet absorbing agents; ultraviolet scattering agents; natural extracts derived from animals and plants; ascorbic acid and derivatives thereof; flavonoids such as anthocyanins and derivatives thereof; vitamins; amino acids; photosensitizers; dyes; pigments; and fragrances.
When the cleansing agent of the present invention contains other ingredients, the content of the other ingredients in the total amount of the cleansing agent is preferably 10 mass % or less, more preferably 0.1 to 5 mass %, and particularly preferably 0.5 to 3 mass %.

〔form〕
The warm-feeling skin cleanser of the present invention may be in any form that can be applied, but is preferably in a gel form. The solvent may be an aqueous solvent such as water or a lower alcohol, but is preferably water.

[How to use]
The warming skin cleanser of the present invention may be applied to dry skin or wet skin, but from the viewpoint of effectively obtaining the warming effect due to the heat of hydration of glycerin (A1), it is preferable to apply it to damp skin.
In addition, since the warming skin cleansing agent of the present invention can be applied evenly and thickly to the skin, it is preferable to take it in the hands and apply it to the skin and spread it evenly. When taking the warming skin cleansing agent of the present invention in the hands and applying it to the skin, it is preferable that the hands are dry.
To explain in detail using a gel-type warming skin cleanser as an example, first take an appropriate amount of the warming skin cleanser on dry palms, and spread the warming skin cleanser all over while massaging the skin. Since the cleanser of the present invention has a warming effect, it opens pores, making it easier to remove keratin and sebum. After that, thoroughly rinse off the warming skin cleanser with water or lukewarm water, and wipe off the water or lukewarm water with a towel or the like.

The present invention will now be described in detail with reference to examples and comparative examples.

[Examples 1 to 5 and Comparative Examples 1 to 5]
The components shown in Table 1 were used to prepare a warming skin cleanser in the composition shown in Table 1, and the composition was evaluated by the following method.
In addition, component (A) is a polyhydric alcohol (A), component (A1) is glycerin, and component (A2) is 1,3-butylene glycol.
The alkylene oxide adduct derivative a of glycerin in component (B) is "WILBRIDE (registered trademark) S- 753" (manufactured by NOF Corporation), which is a polyoxybutylene polyoxyethylene polyoxypropylene glyceryl ether (3BO) (8EO) (5PO) in which a+b is 4.3, c is 1, and the PO/EO content ratio (PO/EO) is 4/5 by mass in the alkylene oxide derivative represented by the above formula (I).
The nonionic surfactants of component (C) are PEG-7 glyceryl coconut oil fatty acid (HLB=13.0) and sorbeth-30 tetraoleate (HLB=11.2).
The acrylic acid-based thickening polymer of component (D) is a carboxyvinyl polymer "CARBOPOL (registered trademark) Ultrez 10 Polymer" (manufactured by Lubrizol Japan, Inc.).
Copolymer a of component (E) is "Lipidure (registered trademark)-PMB" (manufactured by NOF Corporation), which is a binary copolymer consisting of structural units represented by the above formulas (II) and (III). In formulas (II) and (III), ^R1 and ^R2 are each a methyl group, and in formula (III), m=3. The content ratio (n1:n2) (molar ratio) of the structural unit represented by formula (II) to the structural unit represented by formula (III) is 4:1, and the weight average molecular weight is about 600,000.

Twenty men and women (aged 25-45) were used as panelists, who applied the obtained warming skin cleanser thickly to their entire faces using dry hands, left it on for 3 minutes, and then gently rubbed and thoroughly washed off with lukewarm water. During this process, the panelists were asked to evaluate (1) the ease of applying the product evenly and thickly, (2) the duration of the appropriate warming sensation, (3) the lack of dripping on the skin, and (4) the refreshing feeling after washing. The results are shown in Table 1.
The percentages of the components in Table 1 are in mass %. The evaluation criteria for each evaluation item are shown below.

(1) Ease of applying a uniform, thick coat 2 points: It was felt that it was easy to apply a uniform, thick coat.
1 point: I was able to apply a thick coat, but it felt a little lacking in uniformity.
0 points: Difficult to apply thickly.
The total scores of the 20 participants were calculated and judged as follows:
⊚: The total score is 35 points or more, and 0 panelists gave a score of 0. A skin cleanser that is easy to apply evenly and thickly.
Good: The total score was 30 or more and less than 35 points, or the total score was 35 or more and the number of panelists who rated it as 0 point was 1 to 2. Good: The skin cleanser is relatively easy to apply evenly and thickly.
Δ: The total score is 20 or more and less than 30 points.; This skin cleanser is somewhat difficult to apply thickly and evenly.
×: The total score is less than 19 points. The skin cleanser is difficult to apply thickly and evenly.

(2) Duration of moderate warmth 2 points: A moderate warmth was felt for 3 minutes.
1 point: A feeling of warmth was felt for 3 minutes, but the feeling of warmth was not quite adequate.
0 points: No warmth was felt.
The total scores of the 20 participants were calculated and judged as follows:
⊚: The total score is 35 points or more, and 0 panelists gave a score of 0. A skin cleanser that provides a moderate, sustained warming sensation.
Good: The total score was 30 or more and less than 35 points, or the total score was 35 or more and the number of panelists who rated it as 0 point was 1 to 2. Good: The total score was 35 or more and the number of panelists who rated it as 0 point was 1 to 2. Good: The skin cleanser has a moderate warming sensation that lasts for a while.
Δ: The total score is 20 or more but less than 30 points.; This is a skin cleanser that does not have a proper warming sensation and does not last long enough.
×: The total score is less than 19 points. The skin cleanser does not have an appropriate warming sensation and does not last long.

(3) Lack of dripping on skin 2 points: It was felt that the product did not drip easily on the skin when applied.
1 point: When applied, it felt like it was difficult to drip onto the skin.
0 points: It was felt that the product tended to drip onto the skin when applied.
The total scores of the 20 participants were calculated and judged as follows:
⊚: The total score is 35 points or more, and 0 panelists gave a score of 0. A skin cleanser that does not drip easily when applied to the skin.
Good: The total score is 30 or more and less than 35 points, or the total score is 35 or more and the number of panelists who rated it as 0 point is 1 to 2. Good: The skin cleanser is not prone to dripping when applied to the skin.
Δ: The total score is 20 or more and less than 30 points.; The skin cleanser tends to drip slightly when applied to the skin.
×: The total score is less than 19 points. The skin cleanser is prone to dripping when applied to the skin.

(4) Refreshing feeling after washing 2 points: After washing, the skin felt sufficiently refreshed.
1 point: After washing, the skin felt slightly refreshed.
0 points: No refreshing feeling was felt after washing.
The total scores of the 20 participants were calculated and judged as follows:
⊚: The total score is 35 points or more, and 0 panelists gave a score of 0. A skin cleanser that can provide a sufficiently refreshing feeling after cleansing.
Good: The total score is 30 or more and less than 35 points, or the total score is 35 or more and the number of panelists who rated it as 0 point is 1 to 2. A skin cleanser that can impart a refreshing feeling after cleansing.
Δ: The total score is 20 or more and less than 30 points.; This is a skin cleanser that gives a slightly poor feeling of freshness after cleansing.
×: The total score is less than 19 points. The skin cleanser does not leave a clean feeling after washing.

*1 WILBRIDE (registered trademark) S-753 (NOF Corporation)
*2 Carbopol (registered trademark) Ultrez 10 (The Lubrizol Corporation)
*3 Lipidure (registered trademark)-PMB (Ph10) (NOF Corporation)
[An aqueous solution containing 5% by mass of 2-methacryloyloxyethyl phosphorylcholine (MPC)/butyl methacrylate (BMA) copolymer (molar ratio of MPC to BMA (MPC/BMA)=4)]

As is clear from the results shown in Table 1, the warming skin cleansers of Examples 1 to 5 were easy to apply evenly and thickly, provided a sustained moderate warmth during use, were less likely to drip on the skin, and provided a refreshing feeling after cleansing.

On the other hand, the skin cleansing agents of Comparative Examples 1 to 5 did not provide sufficient performance.
In Comparative Example 1, the content of component (A) was low, so it was difficult to apply a thick, uniform layer, the duration of the warmth was impaired, and the cream did not drip sufficiently on the skin.
In Comparative Example 2, since component (B) was not blended, it was difficult to apply a thick, uniform layer, the lasting warm feeling was lost, and the refreshing feeling after washing was insufficient.
In Comparative Example 3, since component (C) was not blended, it was difficult to apply a thick, uniform layer, and the refreshing feeling after washing was insufficient.
In Comparative Example 4, since the content of component (D) was small, the ease of uniformly applying the cream in a thick layer and the lack of dripping on the skin were significantly reduced, and the effect of providing a sustained warming sensation was also reduced.
In Comparative Example 5, since component (E) was not blended, the warm sensation was too strong and the refreshing feeling of the skin after cleansing was impaired.

Claims (1)

75 to 95% by mass of a polyhydric alcohol (A) consisting of glycerin (A1) and a dihydric alcohol (A2) in a mass ratio (A1/A2) of 99/1 to 90/10;
0.1 to 10% by mass of an alkylene oxide adduct derivative (B) of glycerin represented by formula (I),
0.5 to 8 mass% of a nonionic surfactant (C) having an HLB of 10 to 16 and selected from polyoxyethylene fatty acid glyceryl and polyoxyethylene fatty acid sorbitol ,
0.1 to 0.7% by mass of an acrylic acid-based thickening polymer (D),
0.005 to 0.25% by mass of a copolymer (E) containing structural units represented by the following formulas (II) and (III):
Contains a warming skin cleanser.

Gly-[O{(PO) _a (EO) _b }-(BO) _c H] ₃ Formula (I)
(In formula (I), Gly is a residue obtained by removing a hydroxyl group from glycerin, PO is an oxypropylene group, EO is an oxyethylene group, BO is an oxybutylene group, a, b and c are the average molar numbers of PO, EO and BO added, respectively, a+b is 1 to 30, c is 1 to 5, the addition form of PO and EO may be random or block, and the mass ratio of PO/EO is 1/5 to 5/1.)

(In formula (II), R ¹ represents a hydrogen atom or a methyl group.)

(In formula (III), ^R2 represents a hydrogen atom or a methyl group, and m represents an integer of 3 to 18.)