JP2023067658A - Body cleanser composition - Google Patents

Abstract

To provide a body cleanser composition capable of suppressing or eliminating stiff feeling after washing, obtaining good foamability even when hard water is used and providing a moderate foam elasticity so that comfortability can be felt under both warm and cold conditions.SOLUTION: There is provided a body cleanser composition which comprises a component (a): 1 to 20 mass% of an N-acylamino acid-based surfactant represented by the formula (1); a component (b): 5 to 50 mass% of a fatty acid salt having 8 to 22 carbon atoms and a component (c): 1 to 20 mass% of an amphoteric surfactant represented by the formula (2). (for example, sodium N-lauroyl-N-hydroxyethyl-β-alanine or the like) (for example, lauryl hydroxysulfobetaine or the like).SELECTED DRAWING: None

Description

The present invention relates to body cleansing compositions such as body soaps, hand soaps and facial cleansers.

In the body cleansing composition, not only the detergency to remove stains but also foam is considered important. For example, fine and dense foam acts as a cushioning material between the skin and hands or towels when rubbing the skin, and has the effect of reducing friction on the skin. Therefore, effects such as increased detergency can be expected. Against this background, fatty acid salts are widely used as cleansing ingredients to be blended in body cleansing compositions, since they can quickly provide good foam quality (particularly fine and dense foam).
However, although the fatty acid salt has a high detergency, it also removes the moisturizing ingredients from the skin, causing the problem of rough skin and a tight feeling.

Attempts have been made to combine various compounds with fatty acid salts as means for solving such problems. For example, Patent Document 1 discloses a skin cleanser in which a fatty acid salt is combined with a hydrophilic copolymer, and this cleanser suppresses a tight feeling after washing. Further, Patent Document 2 discloses a skin cleanser composition in which an N-long-chain acyl acidic amino acid arginine salt is combined with a fatty acid salt. suppressing feelings.

However, although N-long-chain acyl acidic amino acid type anionic surfactants such as this N-long-chain acyl acidic amino acid arginine salt can reduce the burden on the skin, they contain metal ions such as calcium ions and magnesium ions. Fatty acids and N-long-chain acyl acidic amino acid type anionic surfactants form salts with these metal ions when using hard water, which causes problems such as foaming and deterioration of foam quality.
Therefore, Patent Document 3 shows that by using a specific acylamino acid-based anionic surfactant, good foaming can be obtained even when using hard water.

On the one hand, consumer demands for cleaning foam performance are increasing. For example, not only is it possible to quickly obtain abundant foam, but elastic foam, which is called cushion foam, is important because it gently wraps the application surface and gives a comfortable feel. The detergent composition described above sometimes has poor foam resilience under a specific environment. For example, when lathering is performed under warm conditions such as in a bathroom in the summer, foam resilience is lost and the foam becomes sparse, making it difficult to feel comfortable. On the contrary, when lathering in cold conditions such as in cold regions, the solubility of the fatty acid salt in water decreases, resulting in a decrease in slippage of the acyl amino acid-based anionic surfactant on the application surface, resulting in a stickiness. It feels like a thorn, and it can be difficult to feel comfortable.
Therefore, there is a demand for a body cleansing composition that does not give a tight feeling after washing, lathers well, and has an appropriate foam resilience that provides comfort even under warm or cold conditions.

JP 2016-216427 A JP 2008-94725 A JP 2016-190812 A

The present invention is intended to solve the above problems, it is possible to suppress or eliminate the stiff feeling after washing, obtain good foaming even when using hard water, and furthermore, it can be used under both warm and cold conditions. To provide a body cleansing composition capable of imparting moderate foam resilience that gives a feeling of comfort even in

As a result of intensive studies in view of the above problems, the present inventors have found that a body cleansing composition containing a fatty acid salt contains predetermined amounts of a specific acylamino acid-based anionic surfactant and a specific amphoteric surfactant. The present inventors have found that the above problems can be solved by using

That is, the present invention comprises (a) component: 1 to 20% by mass of an N-acyl amino acid surfactant represented by formula (1), and (b) component: 5 to 5 of a fatty acid salt having 8 to 22 carbon atoms. 50% by mass, component (c): a body cleansing composition containing 1 to 20% by mass of an amphoteric surfactant represented by formula (2).

(In formula (1), R ¹ CO represents a fatty acyl group having 8 to 22 carbon atoms, R ² represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, and R ³ represents a carbon represents a linear or branched alkylene group of number 1 to 4, and M ¹ represents an alkali metal atom, a 1/2 alkaline earth metal atom, an organic ammonium or an amino acid salt.)

(In formula (2), R ⁴ represents an alkyl group having 8 to 22 carbon atoms or an alkenyl group having 8 to 22 carbon atoms, and R ⁵ and R ⁶ each independently represent a methyl group or an ethyl group.)

According to the body cleansing composition of the present invention, it is possible to suppress or eliminate the stiff feeling after washing, to obtain good lather even when using hard water, and to feel comfortable under both warm and cold conditions. It is possible to give a moderate foam elasticity that makes you feel.
The "body cleansing composition" in the present invention is a cleansing composition for cleaning the body surface of each part of the human body, specifically the head, neck, torso, arms and legs including the face. and conceptually encompasses body cleanser compositions for cleansing the whole body, including the hair.

Embodiments of the present invention will be described below.
In this specification, the numerical range specified using the symbol "-" includes both ends (upper limit and lower limit) of "-". For example, "2 to 4" represents 2 or more and 4 or less.

The body cleansing composition of the present invention contains at least the following components (a), (b) and (c). First, the component (a) will be described in order.

[(a) component]
Component (a) used in the present invention is a surfactant represented by the following formula (1).

R ¹ CO in formula (1) represents an aliphatic acyl group having 8 to 22 carbon atoms.
Aliphatic acyl groups include not only acyl groups derived from saturated or unsaturated fatty acids having 8 to 22 carbon atoms, but also acyl groups derived from mixed fatty acids containing two or more of these fatty acids. For example, octanoyl group (capryloyl group), nonanoyl group (pelargonyl group), decanoyl group (caproyl group), undecanoyl group, lauroyl group, myristoyl group, palmitoyl group, stearoyl group, eicosanoyl group, oleoyl group, linolenoyl group, linoleoyl group , arachidinoyl group, and behenoyl group. A mixture of two or more of these acyl groups may also be used, and examples thereof include mixed acyl groups such as coconut oil fatty acid acyl groups, palm kernel oil fatty acid acyl groups, and palm oil fatty acid acyl groups. Lauroyl group, myristoyl group, coconut oil fatty acid acyl group and palm kernel oil fatty acid acyl group are preferred, and lauroyl group, coconut oil fatty acid acyl group and palm kernel oil fatty acid acyl group are more preferred.

R ² in formula (1) represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms.
Examples of R ² include methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group and isobutylene group, preferably ethylene group and n-propylene group. That is, R ² OH in formula (1) includes, for example, a monohydroxyethyl group, a monohydroxypropyl group, a monohydroxyisopropyl group, a monohydroxybutyl group and a 2-hydroxybutyl group. A hydroxyethyl group and a monohydroxypropyl group.

R ³ in formula (1) represents a linear or branched alkylene group having 1 to 4 carbon atoms.
Examples of R ³ include a methylene group, ethylene group, n-propylene group, isopropylene group, n-butylene group and isobutylene group, preferably ethylene group and n-propylene group. That is, R ³ COOH includes, for example, a monocarboxymethylene group, a monocarboxyethylene group, a monocarboxypropylene group, a monocarboxyisopropylene group, a monocarboxybutylene group, a monocarboxyisobutylene group, etc., preferably monocarboxyethylene. is the base.

M ¹ in formula (1) represents an alkali metal atom, a 1/2 alkaline earth metal atom, an organic ammonium or an amino acid salt.
Alkali metal atoms include, for example, sodium and potassium, and alkaline earth metal atoms include, for example, magnesium and calcium. 1/2 in the 1/2 alkaline earth metal atom represents a coefficient for becoming a cation equivalent as a counterion.
Examples of organic ammonium include monoethanolammonium, diethanolammonium and triethanolammonium.
Amino acid salts are, for example, salts formed between amino acids and alkali metals, amino acids and half-alkaline earth metals, or amino acids and organic amines, respectively, which act as counterions for N-acylamino acids. Examples of amino acids that form amino acid salts include valine, leucine, isoleucine, histidine, lysine, methionine, phenylalanine, threonine, tryptophan, asparagine, aspartic acid, alanine, arginine, cysteine, glutamine, glutamic acid, glycine, proline, serine, Tyrosine, N-methylglycine, N-methyl-β-alanine, N-(2-hydroxyethyl)-β-alanine, taurine, methyltaurine and the like. Alkali metals and alkaline earth metals that form amino acid salts include those exemplified above. Examples of organic amines that form amino acid salts include monoethanolamine, diethanolamine, and triethanolamine.
In addition, "organic ammonium" in the present invention does not conceptually include amino acid ammonium formed by an amino acid and an organic amine.
^M1 is preferably sodium, potassium, magnesium, calcium or triethanolammonium, more preferably sodium, potassium or triethanolammonium.

Specific examples of surfactants represented by formula (1) include sodium N-lauroyl-N-hydroxyethylalanine, N-lauroyl-N-hydroxyethylalanine triethanolamine, N-lauroyl-N-hydroxy Propylalanine triethanolamine, N-coconut fatty acid acyl-N-hydroxyethylalanine sodium, and the like.
In the present invention, one or more of the compounds encompassed by the above formula (1) can be appropriately selected and used as the component (a).

The content of component (a) is 1 to 20% by mass, preferably 3 to 15% by mass, more preferably 5 to 10% by mass, relative to the body cleansing composition. If the content of component (a) is too small, it may not be possible to suppress the tightness of the skin, or foaming during cleansing and elasticity (resilience) of the foam may be insufficient. If the content of component (a) is too high, the applied surface may feel sticky, making it difficult to feel comfortable.
When multiple types of surfactants represented by formula (1) are used in combination, the total content of these multiple types should be within the above range.

[(b) component]
Component (b) used in the present invention is a fatty acid salt having 8 to 22 carbon atoms.
The number of carbon atoms in the fatty acid forming the fatty acid salt is preferably 10-20, more preferably 12-18. Examples of fatty acids having 8 to 22 carbon atoms include lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid, and one or more of these can be used. Mixed fatty acids, which are mixtures of fatty acids, can also be used, and examples of such mixed fatty acids include coconut oil fatty acid, palm kernel oil fatty acid, and beef tallow fatty acid. Preferred fatty acids having 8 to 22 carbon atoms are lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, coconut oil fatty acid and palm kernel oil fatty acid, and more preferred are lauric acid, myristic acid, palmitic acid and stearin. is an acid.
Examples of counter ions that form fatty acid salts include alkali metal salts such as sodium and potassium, and organic amine salts such as monoethanolamine, diethanolamine and triethanolamine. Preferred are sodium, potassium and triethanolamine, and more preferred is potassium.
Preferred specific examples of component (b) include potassium laurate, potassium myristate, potassium palmitate, and potassium stearate.
In the present invention, component (b) can be used by appropriately selecting one or more of fatty acid salts comprising combinations of the above fatty acids and counterions.

The content of component (b) is 5 to 50% by mass, preferably 5 to 30% by mass, more preferably 5 to 10% by mass, relative to the body cleansing composition. If the content of component (b) is too low, lathering may be insufficient. Substances tend to precipitate, and it may be difficult to prepare the desired dosage form and exhibit functions.
In addition, when using multiple types of (b) component together, the total amount of content of these multiple types should just be said range.

[Component (c)]
Component (c) used in the present invention is an amphoteric surfactant represented by the following formula (2), that is, an alkylhydroxysulfobetaine type amphoteric surfactant.

R ⁴ in formula (2) represents an alkyl group having 8 to 22 carbon atoms or an alkenyl group having 8 to 22 carbon atoms. The alkyl group and alkenyl group preferably have 8 to 18 carbon atoms. Alkyl and alkenyl groups can be straight or branched chain and include not only alkyl or alkenyl groups derived from saturated or unsaturated compounds, but also alkyl or alkenyl groups derived from mixed compounds containing two or more of these compounds. Included are alkenyl groups, such as alkyl or alkenyl groups derived from mixed fats.
Alkyl or alkenyl groups derived from saturated or unsaturated compounds include, for example, lauryl, myristyl, palmityl, stearyl, oleyl, arachidyl, and behenyl groups. Examples of the mixed fat-derived alkyl group or alkenyl group include a coconut oil fatty acid alkyl group, a palm kernel oil fatty acid alkyl group, a beef tallow fatty acid alkyl group, and the like. Preferred are lauryl group, myristyl group, coconut oil fatty acid alkyl group and palm kernel oil fatty acid alkyl group.

R ⁵ and R ⁶ in formula (2) each independently represent a methyl group or an ethyl group, preferably both R ⁵ and R ⁶ are methyl groups.

Specific examples of the alkylhydroxysulfobetaine-type amphoteric surfactant represented by formula (2) include laurylhydroxysulfobetaine and cocohydroxysulfobetaine.
In the present invention, one or more of the compounds encompassed by the above formula (2) can be appropriately selected and used as the component (c).

The content of component (c) is 1 to 20% by mass, preferably 3 to 15% by mass, more preferably 5 to 10% by mass, relative to the body cleansing composition. If the content of component (c) is too low, lathering during cleansing and elasticity of the foam may be insufficient. The slimy feeling derived from the amphoteric surfactant may be likely to occur.
When multiple types of amphoteric surfactants represented by formula (2) are used in combination, the total content of these multiple types should be within the above range.

The body cleansing composition of the present invention contains at least components (a), (b) and (c), and further contains a solvent such as water.
The content of solvent such as water is usually 10 to 93% by mass, preferably 40 to 90% by mass, more preferably 60 to 85% by mass, based on the body cleansing composition.

The body cleansing composition of the present invention may optionally contain other surfactants, moisturizing agents, oils, water-soluble polymers, preservatives, bactericides, and pH adjusters within a range that does not impair the effects of the present invention. It may contain various optional ingredients commonly used in hair and body cleansers, such as agents.
Other surfactants include cationic surfactants, anionic surfactants (excluding components (a) and (b)), and amphoteric surfactants (excluding components (c)). ), and nonionic surfactants, among which nonionic surfactants are preferred.
Examples of nonionic surfactants include sorbitan laurate, sorbitan palmitate, sorbitan oleate, sorbitan stearate, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan oleate, polyoxy Sorbitan fatty acid esters such as sorbitan ethylene stearate; glycerin fatty acid ester; polyglycerin laurate; polyglycerin lauryl ether; sucrose fatty acid esters such as sucrose laurate and sucrose stearate; polyoxyalkylene alkyl ethers; polyoxyalkylene esters such as PEG-4 lauric acid and PEG-7 glyceryl cocoate; and alkylolamides such as coconut oil fatty acid diethanolamide.

Moisturizers include, for example, glycerin, propylene glycol, 1,3-butylene glycol, diglycerin, sorbitol and the like.
Examples of oils include hydrocarbon oils such as liquid paraffin, solid paraffin, and vaseline; ester oils such as isopropyl myristate, octyldodecyl myristate, isopropyl palmitate, and diisopropyl sebacate; straight silicone oils such as dimethylpolysiloxane; Examples include silicone oils such as modified silicone oils into which ether groups, amino groups, fatty acid amide groups, etc. have been introduced.
Examples of water-soluble polymers include nonionic polymers such as starch, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, guar gum and xanthan gum; anionic polymers such as carboxymethylstarch, carboxymethylcellulose, alginic acid and gum arabic; Cationic starch; dimethyldiallylammonium chloride/acrylamide copolymer (polyquaternium-7), cationized cellulose (polyquaternium-10), dimethyldiallylammonium chloride/acrylic acid copolymer (polyquaternium-22), acrylamide/acrylic acid/chloride Examples include cationic polymers such as dimethyldiallylammonium copolymer (polyquaternium-39).
Examples of antiseptics and disinfectants include benzoic acid or its salts, parabens such as parahydroxybenzoic acid, methyl parahydroxybenzoate, and propyl parahydroxybenzoate, and phenoxyethanol.
Examples of pH adjusters include organic acids such as citric acid and sodium citrate and salts thereof, potassium hydroxide, sodium hydroxide, triethanolamine and the like.

When the body cleansing composition of the present invention contains other optional components, the content thereof is usually 20% by mass or less, preferably 0.1 to 15% by mass, based on the body cleansing composition. , more preferably 1 to 10% by mass.
In the body cleansing composition of the present invention, the total content of components (a), (b), (c) and solvent is usually 80 to 100% by mass, preferably 85 to 100% by mass. %, more preferably 90 to 100% by mass.
Further, when the ratio of the content of component (a) to the content of component (b) is defined as component (a) / component (b), from the viewpoint of the effect of suppressing the tight feeling, component (a) / (b) ) is preferably 0.4 to 4.0, more preferably 0.6 to 2.0.
Furthermore, when the ratio of the total content of components (a) and (c) to the content of component (b) is defined as ((a) component + (c) component) / (b) component, From the viewpoint of suppressing the stickiness of foam, the value of ((a) component + (c) component)/(b) component is preferably 1.4 to 3.2, more preferably 1.6 to 2.4. .

The body cleansing composition of the present invention can be produced according to a conventional method. For example, the above components (a), (b), (c), other optional components, and water are mixed, and adjusted with water so that the total amount of the composition is 100% by mass. to obtain the body cleansing composition of the present invention.

EXAMPLES Next, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited thereto.

[Examples 1 to 7 and Comparative Examples 1 to 6]
<Preparation of body cleansing composition>
After adding each component described in Tables 1 and 2 to water and mixing them to make them uniform, the total amount was adjusted to 100% by mass with water, and the bodies of Examples 1 to 7 and Comparative Examples 1 to 6 A cleaning composition was prepared.
In addition, as each component in Tables 1 and 2, a commercially available product for cosmetics was used. The content of each component in Tables 1 and 2 is shown in % by mass. The blending amount of each component is a value converted from the active ingredient (target component) or solid content contained in the blended product.

The body cleansing compositions obtained in Examples and Comparative Examples were used as samples and evaluated as follows. The numerical value written together with each evaluation result in Tables 1 and 2 indicates the evaluation result or average score obtained in each case.

<Evaluation of Body Cleansing Composition>
(1) Suppression of tight feeling A panel of 20 men and women (24 to 40 years old) took 5 g of the sample in their hands, washed their hands with hot water with a hardness of 150 and 40 ° C., and washed their hands several times after washing. The firmness of the skin after being shaken and drained was evaluated. 2 points were given when no feeling of tightness was felt, 1 point was given when a feeling of tightness was slightly felt, and 0 point was felt when a feeling of tightness was felt.
⊚: The total score is 35 points or more; no stiff feeling is felt.
◯: The total score is 30 or more and less than 35; no stiff feeling is felt.
Δ: The total score is 20 or more and less than 30; Slightly tight feeling is felt.
x: The total score is less than 20 points; a tight feeling is felt strongly.

(2) Foaming A panel of 20 men and women (ages 24 to 40) took 5 g of the sample and evaluated foaming when lathered with hot water having a hardness of 150 and a temperature of 40°C. A total score of 20 people was obtained and evaluated as follows, with 2 points for feeling that foaming was good, 1 point for feeling that foaming was slightly good, and 0 point for feeling that foaming was poor.
A: The total score is 35 points or more; foaming is very good.
◯: The total score is 30 or more and less than 35; foaming is good.
Δ: Total score is 20 or more and less than 30; Foaming is not so good.
x: The total score is less than 20 points; foaming is poor.

(3) Foam resilience at warm temperature 3 g of the sample was placed in a commercially available whisk, and 10 g of hot water having a hardness of 150 and a temperature of 40°C was used to foam. Note that the whisk is a device having a cylindrical container and a lid that can move up and down in the container and has a hole in the center. The foam can be generated by moving the lid up and down.
Using a rheometer (MCR302) manufactured by Anton Paar Japan Co., Ltd., the above foam was prepared on a plate as a sample for measurement, and the plate temperature was 40 ° C., the angular frequency was 7 (rad / s), and the vibration angle was 90. °, the foam resilience was evaluated by reading the value of the storage modulus G' (Pa) 60 seconds after the start of measurement. In addition, the number of times of measurement was 3 times, and the average value was calculated.
⊚: G' value is 0.30 Pa or more; the foam has excellent resilience and provides good comfort.
◯: G' value is 0.20 Pa or more and less than 0.30 Pa; the foam has elasticity and feels comfortable.
Δ: G' value is 0.10 Pa or more and less than 0.20 Pa; the foam has little elasticity and is difficult to feel comfortable.
x: G' value is less than 0.10 Pa; the foam lacks elasticity and does not feel comfortable.

(4) Foam resilience when cold 3 g of the sample was placed in the above-mentioned whisk, and 10 g of cold water having a hardness of 150 and a temperature of 5° C. was whipped. Using a static and dynamic friction measuring device (TL201Tt) manufactured by Trinity Lab Co., Ltd., quickly place about 1 mL of the above foam on the artificial leather, press the foam with a tactile sensor, and apply a vertical load of 50 g. μ) was read to evaluate the stickiness of the foam. In addition, the number of times of measurement was 3 times, and the average value was calculated.
⊚: μ value is less than 0.30; resistance to the initial movement is small, so the foam does not feel sticky when it tries to stay in place. That is, it is a foam that imparts a good and pleasant feel to the skin.
◯: μ value is 0.30 or more and less than 0.45; Since the resistance to the initial movement is slightly low, the stickiness caused by the foam trying to stay in place is hardly felt. That is, it is a foam that imparts a pleasant feeling to the skin.
Δ: μ value is 0.45 or more and less than 0.60; resistance to the initial movement is somewhat high, and the foam tends to stay in place, giving a slightly sticky feeling. That is, it is a foam that imparts a slightly unpleasant feel to the skin.
x: μ value is 0.60 or more; resistance to the initial motion is very large, and the foam gives a strong feeling of stickiness as it tries to stay in place. That is, it is a foam that imparts an unpleasant feeling to the skin.

Examples 1 to 7 were evaluated favorably in all items.
On the other hand, in Comparative Example 1, although the stiff feeling was not felt, since the content of the component (b) was small, the lather was insufficient and the feel of the foam in cold weather was also insufficient.
Comparative Example 2 contains sodium N-coconut fatty acid acyl-N-methyltaurate, which is an N-acyl amino acid surfactant, as component (a′) instead of component (a). Since the synergistic effect of the component and the component (c) was not exhibited, the elasticity of the foam was insufficient in warm and cold conditions.
Comparative Example 3 contains N-lauroyl-N-methyl-β-alanine sodium, which is an N-acylamino acid-based surfactant, as component (a′) instead of component (a). Since the synergistic effect of the component and the component (c) was not exhibited, the elasticity of the foam in warm and cold conditions was insufficient, as in Comparative Example 2. Moreover, foaming was not so good.

Comparative Example 4 contains components (a) and (b), but instead of component (c), it contains coconut oil fatty acid amidopropyl betaine as component (c'), which is an amphoteric surfactant. Therefore, the synergistic effect of the components (a) and (c) was not exhibited, and the elasticity of the foam was insufficient in warm and cold conditions.
Comparative Example 5 contains components (b) and (c), but does not contain component (a). Insufficient bubbling occurred due to precipitation due to reduced force. Furthermore, since the synergistic effect of the components (a) and (c) was not exhibited, the elasticity of the foam was insufficient in both warm and cold conditions.
In Comparative Example 6, since the component (c) was not contained, the synergistic effect of the components (a) and (c) was not exhibited, and the elasticity of the foam in warm and cold conditions was insufficient. there were.

The body cleansing composition of the present invention is not limited to a liquid form or a gel form as long as it is intended for cleaning the body, and can be used as, for example, a body shampoo, a facial cleanser, and a hand soap. .

Claims (1)

(a) component: 1 to 20% by mass of an N-acyl amino acid-based surfactant represented by formula (1);
(b) component: 5 to 50% by mass of a fatty acid salt having 8 to 22 carbon atoms,
Component (c): A personal cleansing composition containing 1 to 20% by mass of an amphoteric surfactant represented by formula (2).

(In formula (1), R ¹ CO represents a fatty acyl group having 8 to 22 carbon atoms, R ² represents a single bond or a linear or branched alkylene group having 1 to 4 carbon atoms, and R ³ represents a carbon represents a linear or branched alkylene group of number 1 to 4, and M ¹ represents an alkali metal atom, a 1/2 alkaline earth metal atom, an organic ammonium or an amino acid salt.)

(In formula (2), R ⁴ represents an alkyl group having 8 to 22 carbon atoms or an alkenyl group having 8 to 22 carbon atoms, and R ⁵ and R ⁶ each independently represents a methyl group or an ethyl group.)