JP2001226697A - Solid soap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid soap which is low irritative against the skin, hardly collapsed by dissolving, has good foamability, and gives a good sense of use. SOLUTION: This solid soap comprising fatty acid salts and an acidic amino acid or acidic amino acid salt, characterized in that the formulation molar ratio of the fatty acid salts to the acidic amino acid or acidic amino acid salt is 6/4 to 3/7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid soap for washing the skin used for the face and the body, and more particularly to a solid soap which has low skin irritation, does not dissolve easily, and has good foaming and feeling upon use. About soap.

[0002]

2. Description of the Related Art Soap has long been used as a cleansing agent for the face and body, and has the excellent property of being biodegradable and environmentally friendly. It is still widely used as a skin cleanser. However, an alkali metal salt of a fatty acid is mainly used as a main agent of the solid soap, and when dissolved in water, it is hydrolyzed to exhibit an alkalinity of about pH 10. Human skin is weakly acidic, but when the skin becomes alkaline, the skin becomes sensitive and susceptible to external stimuli, causing skin diseases.
Therefore, the use of solid soap composed of an alkali metal salt of a fatty acid may be a problem, especially for skin having skin diseases such as hypersensitivity. For this reason, so-called superfat soaps, in which free fatty acids are added to soap to reduce irritation to the skin, have been developed.
Therefore, there is a limit to the decrease in skin irritation.

In order to solve this problem, solid soaps using alkanolamine salts of fatty acids and basic amino acid salts of fatty acids have been developed. JP-A-57-8049
No. 8 discloses solid soap containing acyl glutamate as a main component, and JP-A-8-27482 discloses a solid soap containing acyl isethionate as a main component. These solid soaps are prepared from alkali metal salts of fatty acids. Skin irritation is lower than that of solid soap. However, these solid soaps have problems in any of the properties that solid soaps should originally have, such as foaming, feeling of use, and difficulty in melting. For example, alkanolamine salts of fatty acids and basic amino acid salts are easily disintegrated,
Acyl glutamate and acyl isethionate have a slimy feeling during washing, resulting in poor usability. Therefore,
Although such solid soap has the effect of alleviating the irritation to the skin, it has not yet been widely used, and at present the solid soap comprising an alkali metal salt of a fatty acid is still mainstream.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid soap which has low irritation to the skin, hardly dissolves, and has good foaming and feeling upon use.

[0005]

That is, the present invention provides:
(1) A solid soap comprising a fatty acid salt and an acidic amino acid or an acidic amino acid salt, wherein the mixing molar ratio of the fatty acid salt and the acidic amino acid or the acidic amino acid salt is 6/4 to 3/7.
(2) a base pair for a carboxyl group of a fatty acid constituting a fatty acid salt is composed of an alkali metal and a basic amino acid, and the equivalent ratio of the alkali metal to the basic amino acid is 9/1 to 1; (3) solid soap according to (1), wherein the fatty acid constituting the fatty acid salt is 15 to 35% by weight of lauric acid, 45 to 75% by weight of myristic acid, and 5 to 20% by weight of palmitic acid (1) solid soap according to (1) or (2), wherein the fatty acid constituting the fatty acid salt is hydroxy. 10 to 10 saturated fatty acids
The solid soap according to (3), which is 25% by weight or 3 to 10% by weight of a branched saturated fatty acid and is transparent.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The fatty acid salts used in the present invention include alkali metal salts such as sodium and potassium, ammonium salts, organic ammonium salts such as monoethanolamine, diethanolamine and triethanolamine, arginine, lysine, histidine and the like. Fatty acid salts composed of one or more basic amino acid salts such as ornithine, etc., are preferred, and alkali metal salts and basic amino acid salts are preferred. When an alkali metal salt and a basic amino acid salt are used, the equivalent ratio between the alkali metal salt and the basic amino acid salt is preferably 9/1 to 5/5, and more preferably 8/2 to 6/4. . When the equivalent ratio is larger than 9/1, the pH is high, the irritation to the skin becomes strong, and the slimy feeling during washing tends to be high. 5/5
If it is smaller, melting collapse tends to occur.

Examples of the acidic amino acid or the acidic amino acid salt used in the present invention include aspartic acid, glutamic acid, and salts of sodium and potassium thereof, preferably sodium salt of glutamic acid, for example, monosodium glutamate. It is a salt monohydrate.
The compounding amount of the fatty acid salt and the acidic amino acid or the acidic amino acid salt is such that the molar ratio of the fatty acid salt and the acidic amino acid or the acidic amino acid salt is 6/4 to 3/7, preferably 5/5.
４4/6. If the molar ratio is greater than 6/4, a slimy feeling after washing is likely to occur, and a feeling after washing is also deteriorated. If it is smaller than 3/7, melt collapse tends to occur, and a favorable foam quality cannot be obtained.

The fatty acid constituting the fatty acid salt used in the present invention is not particularly limited as long as it is generally used for soap. For example, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid Saturated fatty acids such as, unsaturated fatty acids such as oleic acid, sabinic acid,
2-hydroxytetradecanoic acid, iprolic acid, 2-hydroxyhexadecanoic acid, yarapinolic acid, uniperic acid, alurilic acid, 2-hydroxystearic acid,
Branching of hydroxy-saturated fatty acids such as 12-hydroxystearic acid, 18-hydroxystearic acid, castor oil-hardened fatty acids, 2-ethylhexanoic acid, isononanoic acid, isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, etc. Mixed fatty acids such as saturated fatty acids, coconut oil fatty acids, palm kernel oil fatty acids, and tallow fatty acids are exemplified. From the viewpoint of fast foaming and storage stability, lauric acid, myristic acid, and a saturated fatty acid such as palmitic acid are preferable.
35% by weight, 45% to 75% by weight of myristic acid and 5% to 20% by weight of palmitic acid, and the total of saturated fatty acids is 85% to 100% by weight of the total fatty acids.

In the solid soap of the present invention in which the total of the saturated fatty acids of the fatty acid constituting the fatty acid salt is 85 to 100% by weight of the total fatty acid, when obtaining the transparent solid soap, the fatty acid constituting the fatty acid salt is hydroxysaturated. It preferably contains fatty acids or branched saturated fatty acids. Examples of hydroxy saturated fatty acids include savininic acid, 2-hydroxytetradecanoic acid, iprolic acid, 2-hydroxyhexadecanoic acid, yarapinolic acid, uniperic acid, aluritic acid, 2-hydroxystearic acid, 12-hydroxystearic acid, 18-hydroxystearic acid, Examples thereof include hydroxystearic acid and castor oil-hardened fatty acids, and preferably castor oil-hardened fatty acids. The content of the hydroxy-saturated fatty acid is 10 to 25 of the fatty acid constituting the fatty acid salt.
% By weight is preferred, and 15-20% by weight is more preferred.
If the content is less than 10% by weight, transparency may be reduced. If the content is more than 25% by weight, the foaming property may be reduced, and a preferable foam quality may not be obtained. is there. Examples of the branched saturated fatty acid include 2-ethylhexanoic acid, isononanoic acid, isodecanoic acid, isotridecanoic acid, isomyristic acid, isopalmitic acid, isostearic acid, and the like, with isostearic acid being preferred. The content of the branched saturated fatty acid is preferably 3 to 10% by weight of the fatty acid constituting the fatty acid salt,
8% by weight is more preferred. If the content is less than 3% by weight, transparency may be reduced, and if the content is 1% by weight.
If the content is more than 0% by weight, the foaming property may be reduced, and a preferable foam quality may not be obtained.

[0010] The solid soap of the present invention may optionally contain various optional ingredients commonly used in cosmetics, quasi-drugs and the like as long as the effects of the present invention are not impaired. Such optional components include, for example, α-hydroxy acids such as citric acid, tartaric acid and malic acid or salts thereof, polyglycerins such as diglycerin and decaglycerin, erythritol, threitol, pentaerythritol, adenyl, arabitol, xylitol, Sugar alcohols such as mannitol, galactitol, inositol and maltitol, sugars such as glucose and trehalose, polyhydric alcohols such as dipropylene glycol and polyethylene glycol, higher alcohols, silicone derivatives, protein derivatives, squalane, jojoba oil, olive oil, castor Oily bases such as oils, lanolin, lecithin, fatty acid esters of polyethylene glycol, etc., lower alcohols such as ethanol and isopropyl alcohol, polyoxyethylene sorbitan fatty acid esters Polyoxyethylene alkyl ethers, nonionic surfactants such as alkanolamides, amidopropyldimethylaminoacetic acid betaines, alkylaminoacetates, amphoteric surfactants such as amide amino acid salts, acylmethyltaurine salts, alkyl ether sulfates, Anionic surfactants such as amide ether sulfates, carboxyvinyl polymers,
Examples include water-soluble polymers such as carboxymethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylcellulose, bactericides, chelating agents, antioxidants, ultraviolet absorbers, natural extracts derived from animals and plants, pigments, and fragrances.

When the solid soap of the present invention is used as a transparent solid soap, a clarifying agent such as sucrose, sorbitol, glycerin, propylene glycol, 1,3-butylene glycol or the like is used in accordance with the usual formula for transparent solid soap. Can be blended.

The solid soap of the present invention can be produced by a mechanical kneading method or a frame kneading method. However, when the solid soap of the present invention is made into a transparent solid soap, it can be produced by a frame kneading method. preferable.

[0013]

EFFECT OF THE INVENTION The solid soap of the present invention has low irritating property to the skin, is hard to melt and disintegrate, has good foaming and feeling of use, and has cosmetic soap, hypoallergenic soap, transparent soap, mustache sled soap, baby soap, It can be used for medicated soaps and the like.

[0014]

EXAMPLES The present invention will be specifically described with reference to examples. Example 1 Fatty acid composition shown in Table 1 (coconut fatty acid / tallow fatty acid = 2
216 g of a fatty acid mixture consisting of
An L-double-arm kneader (Moriyama Seisakusho SN-1) was heated to about 80 ° C., and 40 g of sodium hydroxide, an equimolar base pair with fatty acid, was ion-exchanged with 410 g of ion-exchanged water (1. (6 times the amount), and the mixture was stirred and mixed at 85-95 ° C. for about 5 minutes, and then monosodium glutamate monohydrate was mixed with a fatty acid salt and an acidic amino acid or an acidic amino acid salt shown in Table 1. Ratio (4.0 / 6.
According to 0), 276 g was added, 102 g of glycerin (0.4 times the amount of the fatty acid salt) was added, and stirring and mixing were further continued at that temperature to adjust the water content while drying. And
The composition was kneaded and extruded with an extruder (manufactured by Sato Iron Works) to obtain a bar-shaped soap, and then molded with a stamping machine (MP-2B manufactured by Riken Seiki Co., Ltd.) to obtain a solid soap. Obtained. The following evaluation was performed. Examples 2 to 8 and Comparative Examples 1 to 5 Solid soaps were prepared with the composition shown in Table 1 in the same manner as in Example 1 and evaluated.

Example 9 Fatty acid composition shown in Table 2 (lauric acid / myristic acid / palmitic acid / castor-cured fatty acid = 20/50/10/2)
In a glass 3L four-necked flask equipped with a stirrer and stirring blades, 230 g of the fatty acid mixture composed of 0) was added, and ethanol (0.4 times the amount of the fatty acid) was added. Dissolve 32 g of sodium hydroxide consisting of equimolar base pairs and 35 g of arginine (sodium hydroxide / arginine = 8.0 / 2.0 equivalent ratio) in 416 g of ion-exchanged water (1.4 times the fatty acid salt). After adding the aqueous alkali solution and stirring for 10 minutes, the molar ratio of the monosodium glutamate monohydrate to the fatty acid salt and the acidic amino acid or the acidic amino acid salt shown in Table 2 (4.4 / 5.6)
234 g, sucrose 89 g (0.3 times the amount of the fatty acid salt), and glycerin (0.3 times the amount of the fatty acid salt)
Was added and stirred and mixed at 70 ° C. This solution was solidified by cooling, cut and dried to obtain a solid soap. The following evaluation was performed. Examples 10 to 15 and Comparative Examples 6 to 8 Solid soaps were prepared with the composition shown in Table 2 in the same manner as in Example 9 and evaluated.

(1) Skin irritation An aqueous solution having a soap concentration of 10% by weight was prepared and used as a test solution to conduct a closed patch test. The test subjects were males in their 20s and 30s having healthy skin, and 5 test subjects per test solution. The test solution was applied to the inner right upper arm, and purified water was applied to the inner left upper arm as a control. After 24 hours from the application, the patch was peeled off, the test portion was washed with 500 ml of purified water, and then rested for 1 hour. After 1 hour, the test portion of the control and the test solution was visually judged. Two points when there was little difference between the control and the test part of the test solution, one point when the test solution was slightly reddened compared to the control, and one with apparent redness or edema in the test solution In the case where the score was 0, the evaluation was made based on the following three scales based on the total score of the five persons. Low skin irritation. (7 points or more in total) Skin irritation is slightly high. (4 points or more and 6 points or less in total) High skin irritation. (3 points or less in total)

(2) pH An aqueous solution having a soap concentration of 0.25% by weight is prepared and
PH measured by Horiba, Ltd. pH meter M-1
2 and evaluated in the following three stages. ：: pH is less than 9 △: pH is 9 to 10 ×: pH is more than 10 (3) Foaming property Prepare an aqueous solution having a soap concentration of 0.25% by weight, and immediately apply it at 40 ° C. by the Rossmiles method. After 5 minutes, the foam height was measured, and those having a foam retention rate of 90% or more determined by the following formula were evaluated as solid soap with good foaming. Foam persistence rate (%) = [(height of foam after 5 minutes) / (height of foam immediately after injection)] × 100

(4) Solubility Using a soap friction solubility tester manufactured by Kuramochi Chemical Instruments Co., Ltd., rotate the film with the bottom surface of the soap cut into a rectangular parallelepiped with a bottom area of 3 cm ² and the film adapted to water. Then, the weight (W1) was measured by rubbing for 5 minutes, and the bottom surface of the soap was rubbed again with the water-adapted film for 5 minutes to measure the weight (W2), and the friction solubility was calculated by the following equation. Then, a soap having a frictional solubility of 10 or more was evaluated as a solid soap having good solubility.
The water temperature was set at 25 ° C. Friction solubility = [(W1−W2) × 100] / 3

(5) Foam Quality The foam quality when washing face with solid soap was determined as follows, with 10 men and women as panelists. From the total score of 20 people, 2 points when the foam felt fine and elastic, 1 point when the foam felt slightly coarse, and 0 when the foam felt coarse and inelastic, Next 3
It was evaluated on a scale. Good foam quality. (Total score is 30 points or more) The foam quality is somewhat poor. (Total score is 20 points or more and less than 30 points) Awa trade is bad. (Total points are less than 20 points)

(6) Sensation of slimming at the time of washing Ten male and female persons were panelists, and the slimming sensation at the time of washing after performing face washing with solid soap was determined as follows. 2 points when no slimy feeling was felt during washing, and 1 point when a slightly slimy feeling was felt during washing.
Points and the slimy feeling were persistent and felt that rinsing took a long time, and the points were evaluated as 0 points. Good foam removal during rinsing. (Total score is 30 points or more) Bubble running out during rinsing is somewhat poor. (Total points are 20 points or more and 3 points
(Less than 0 points) Foaming during rinsing is poor. (Total points are less than 20 points)

(7) Feeling after Washing The feeling after washing face with solid soap was determined as follows, with 10 men and women as panelists.
2 points for feeling smooth after washing, 1 point for feeling not refreshing
Point, if you feel that it is not refreshed at all,
From the total score of 0 persons, the following three grades were evaluated. Good feeling after washing. (Total point is 30 points or more) The feeling after washing is slightly poor. (Total score is 20 or more and less than 30) The feeling after washing is poor. (Total points are less than 20 points)

(8) Solubility The solid soap is immersed in water at 25 ° C. for 1 hour, then dried for 2 hours, and the surface condition is visually observed to judge as follows. The solid soap was evaluated. ◎: Almost the same as the state before the test and no melting and collapse occurred. ：: Only the surface is soft and the inside is hard, and almost no melting and collapse occurs. Δ: Slightly soft inside, slightly melted and collapsed. ×: Softened to the inside and completely melted and collapsed.

(9) Storage stability The solid soap was stored in an open system at 40 ° C. for one month, and its appearance was observed and evaluated on the following three scales. ：: Good stability (no change in appearance and odor) △: Slightly poor stability (slightly colored, or slightly deteriorated odor) ×: Poor stability (significantly colored, or markedly deteriorated odor) )

(10) Transparency The transparency of the solid soap samples of Examples 4 to 6 and Comparative Examples 5 to 7 was visually observed and judged as follows. Was evaluated. ：: Uniform transparency, no turbidity inside. ：: Transparency was observed, but some turbidity was observed inside. Δ: Transparent, but remarkably turbid inside was observed. X: Transparency is not recognized. Tables 3 and 4 show the evaluation results of Examples 1 to 10 and Comparative Examples 1 to 8.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

As can be seen from Examples 1 to 15, the solid soap using the component of the present invention has low skin irritation, high foaming properties and good foam quality, and has good foam removal during washing. In Examples 9 to 15, which were transparent solid soaps, the solid soaps had good transparency.

On the other hand, in Comparative Examples 1 to 8, sufficient performance was not obtained. Since the solid soap of Comparative Example 1 does not contain an acidic amino acid or an acidic amino acid salt, the pH and the skin irritation are high, the slimy feeling during washing is persistent, and the feel after washing is poor. Since the solid soap of Comparative Example 2 does not contain an acidic amino acid or an acidic amino acid salt, the solid soap after washing is persistent, and the feel after washing is poor. In the solid soap of Comparative Example 3, since the molar ratio of the fatty acid salt to the acidic amino acid or the acidic amino acid salt exceeds 6/4, the slimy feeling during washing is persistent, and the feeling after washing is poor. Comparative Example 4 and Comparative Example 5
In the solid soap, since the mixing molar ratio of the fatty acid salt and the acidic amino acid or the acidic amino acid salt is smaller than 3/7, preferable foam quality cannot be obtained, and dissolution collapse has occurred.

Since the solid soap of Comparative Example 6 contains no acidic amino acid or acidic amino acid salt, the pH and skin irritation are high, the slimy feeling during washing is persistent, the feel after washing is poor, and the transparency is low. Can not be obtained. In the solid soap of Comparative Example 7, the molar ratio of the fatty acid salt to the acidic amino acid or the acidic amino acid salt exceeded 6/4.
The pH and skin irritation are high, the slimy feeling during washing is persistent, the feel after washing is poor, and the transparency is low. In the solid soap of Comparative Example 8, since the mixing molar ratio of the fatty acid salt and the acidic amino acid or the acidic amino acid salt was smaller than 3/7, a favorable foam quality was not obtained, the feel after washing was poor, and the dissolution collapse occurred. .

Claims (4)

[Claims] 1. A solid soap comprising a fatty acid salt and an acidic amino acid or an acidic amino acid salt, wherein the compounding molar ratio of the fatty acid salt to the acidic amino acid or the acidic amino acid salt is from 6/4.
Solid soap characterized by being 3/7. 2. A base pair for a carboxyl group of a fatty acid constituting a fatty acid salt is composed of an alkali metal and a basic amino acid, and the equivalent ratio of the alkali metal to the basic amino acid is 9
The solid soap according to claim 1, wherein the ratio is from / 1 to 5/5. 3. The fatty acid constituting the fatty acid salt contains 15 to 35% by weight of lauric acid, 45 to 75% by weight of myristic acid and 5 to 20% by weight of palmitic acid, and the total of saturated fatty acids is 85% of the total fatty acids. The solid soap according to claim 1 or 2, wherein the amount is from 100 to 100% by weight. 4. The solid soap according to claim 3, wherein the fatty acid constituting the fatty acid salt is transparent, containing 10 to 25% by weight of a hydroxy saturated fatty acid or 3 to 10% by weight of a branched saturated fatty acid.