JPS6026766B2 - Method for preventing deterioration of color tone and fragrance tone of cosmetic base material comprising amide monoamine type amphoteric activator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing deterioration of the color tone and fragrance tone of a cosmetic base material comprising an amide monoamine type amphoteric surfactant.

More specifically, the present invention relates to a method of preventing deterioration of the color tone and fragrance tone of the cosmetic base material by adjusting the pH to 8 to 10 with a hydrogen salt of a hydroxy polyhydric carboxylic acid. In recent years, amidomonoamine type amphoteric active agents have come to be used as cosmetic base materials such as shampoos, conditioners, and fluid facial soaps, but the synthesized aqueous solution form of amidomonoamine type amphoteric active agents has a pH of 11 to 13. Therefore, when used as a base material for cosmetics, it is necessary to adjust the pH to a lower range.

Previously, the pH of such amide monoamine type amphoteric surfactants was adjusted using inorganic acids such as hydrochloric acid and sulfuric acid;
When H-adjusted products are exposed to sunlight for a long time or stored at high temperatures, they cause significant coloration and deterioration of fragrance, which tends to reduce their commercial value as cosmetics. The present inventors investigated to solve this problem and found that if the fence of an amidomonoamine type amphoteric active agent is adjusted with a hydrogen salt of a hydroxy polyhydric carboxylic acid, the color tone and scent tone of the active agent will change over time. The present inventors have discovered that the active agent can be advantageously used as a base material for perfumery and cosmetics, and have accomplished the present invention.

That is, the present invention provides a color tone and fragrance tone of a cosmetic base material comprising an amide monoamine type amphoteric active agent, which is characterized in that the pH of the amide monoamine type amphoteric active agent is adjusted to 8 to 10 at the hydrogen temperature of a hydroxy polyhydric carboxylic acid. The present invention provides a method for preventing deterioration of.

The amide monoamine type amphoteric surfactant to which the present invention can be applied has a structural formula (wherein, R is an alkyl group having 7 or more carbon atoms, R2 is hydrogen or an alkoxy group having 2 to 4 carbon atoms, and R3 is a
-4 alkylene group, R4 is hydrogen or an alkoxy group having 2 to 4 carbon atoms, R5 is an alkylene group having 1 to 2 carbon atoms, M is hydrogen, sodium or potassium), and is a fatty acid or a fatty acid ester. It can be produced by amphoterizing amidoamine or imidazoliso obtained by dehydration condensation of and diamine.

In particular, the hydrogen salts of hydroxy polycarboxylic acids used for pH adjustment in the present invention include citric acid-sodium salt, citric acid disodium salt, citric acid-potassium salt,
Dipotassium citrate, sodium malic acid, monopotassium malic acid, sodium hydrogen tartrate, and potassium hydrogen tartrate are preferred.

The amount used varies depending on the type of amphoteric active agent and the manufacturing method, but it is the amount necessary to adjust the pH of the amphoteric active agent to 8 to 10, and is approximately 2 to 20% by weight of the amphoteric active agent. It is. To adjust the pH of the above amphoteric activator with a hydrogen salt of a hydroxy polycarboxylic acid, place the amphoteric activator in an air conditioning tank, add the hydrogen salt of a hydroxy polycarboxylic acid in the form of powder or aqueous solution, and heat the mixture at 20 to 80oC. Stir for several hours.

The amide monoamine type amphoteric surfactant whose pH is adjusted to 8 to 10 according to the present invention does not deteriorate in color tone or fragrance even when stored at 500C for one month, and can be used as a base material for cosmetics such as shampoos, conditioners, and liquid soaps. Do not reduce the product value.

Moreover, by adjusting the pH in this way, the performance as a cosmetic base material is not impaired in any way. If P
If H is adjusted lower than 8, the amphoteric active agent will be significantly discolored due to long-term storage and produce an off-odor, while if adjusted higher than 11, the aroma will deteriorate, so the bait adjustment must be within the range of 8 to 10. Furthermore, organic acids other than hydrogen salts of hydroxy polycarboxylic acids, such as acetic acid, glycolic acid, succinic acid, lactic acid, etc., do not have the effect of preventing deterioration of color tone and fragrance like hydrogen salts of hydroxy polycarboxylic acids. I can't do it.

Next, the present invention will be explained by examples.

Example 1 1 mol of N-lauroyl-N'-8-hydroxyethylethylenediamine obtained by dehydration condensation from lauric acid and aminoethyl ethanolamine and 1.5 mol of ethyl acrylate were combined with a stirrer, a thermometer, and 1.5 mol of ethyl acrylate. The mixture was placed in two four-necked flasks equipped with a condenser and reacted at 8020 for 4 hours to obtain a pale yellow transparent product.

527 ml of water and 1.5 mol of sodium hydroxide were added, and the mixture was further saponified at 80 ml for 2 hours. The product is 40% N
-Lauroyl-N'-8-Hydroxyethyl-N'-sodium carboxyethylethylene diamine. The color tone (Gardner color) was 4, and the fragrance tone was good. Powders of monosodium citrate, sodium malate, and potassium hydrogen tartrate were added to this amphoteric activator (40% aqueous solution) at room temperature, stirred for 1 hour to adjust the pH to 6 to 11, and then stirred at 5000 for 1 hour. We stored it for a month and examined changes in color and aroma. The results are shown in Tables 1 and 2. Table 1 shows the color tone and Table 2 shows the fragrance tone. Although the pH was not adjusted, the color tone after one month under the same conditions was 4, and the aroma tone was B ~
It was C. Table 1 Measurement method: Measurement was carried out in accordance with ASTM-01544 using a Gardner and Liage colorimeter, filling a sample into a Gardner color tube, and reading a value that matched the standard color.

Evaluation: Valued from 1 to 18, with 1 being the thinnest 18
is the darkest.

The number 1 on the shoulder indicates that it is dark, and the number 1 on the shoulder indicates that it is light.

Displays A, B, and C of the second incense tone indicate the following conditions A: Good with no change in fragrance B: Change in fragrance tone, usable C: Significant change in fragrance tone As is clear from the above results, there is no change in color tone or fragrance in the pH range of 8 to 10, and the usefulness of the amphoteric active agent as a base material for cosmetics is satisfactory. be.

Example 2 2-alkyl-N-8-hydroxyethylimidazoline was produced from coconut fatty acid and aminoethyl ethanolamine by dehydration reaction of 2 moles, and 1 mole of the product and 1.5 moles of ethyl acrylate were produced. and 2.0 mol of water are placed in the same flask as in Example 1 and reacted at 80°C for 2 hours to obtain a pale yellow transparent liquid.

To this was added 554 ml of water and 1.5 mol of sodium hydroxide, and saponification was further carried out at 8,000 ℃ for 2 hours. The product is a 40% aqueous solution containing N-alkyloyl-N-8-hydroxyethyl-N'-sodium carboxyethylethylenediamine as a main component, and the aqueous solution has a pH of
12. The color tone (Gardner color) was 4-, and the fragrance tone was A. Add 3.8 ml of monosodium citrate to the aqueous solution at room temperature.
% by weight was added and the pH was adjusted to 9, and 9% by weight of disodium citrate was added and the pH was adjusted to 9 and stored at 50° C. for 1 month. The result is that the color tone is 4.
The acceptance score was A in all cases, and no deterioration was observed in either color tone or fragrance tone. Example 3 N-lauroyl-N'-8-hydroxyethylethylenediamine was ampholyzed with sodium monochloroacetate to form N-
Lauroyl-N'-8-hydroxyethyl-N'-sodium carboxymethylethylenediamine was obtained.

Sodium malate was added to the aqueous solution (pH 11) of the product to adjust the pH to 8. The color tone (Gardner color) at this time was 4, and the aroma tone was A. This is 5 pi 0 and 1
As a result of examination after storage for a month, there was no change in color tone or aroma tone. Example 4 Stearic acid was used instead of lauric acid and the amount of water was 102
A 30% aqueous solution of N-stearoyl-N-B-hydroxyethyl-N'-sodium carboxyethylethylenediamine was obtained in the same manner as in Example 1 except that step 8 was removed.

The pH of the aqueous solution is 25q0 and 12. The color tone (Gardner color) is 4, and the fragrance tone is A. Potassium hydrogen tartrate was added at room temperature and the pH was adjusted to 10.
When stored for a month, the color tone was 40 and the aroma tone was A.
Reference Example The acid shown in Table 3 was added to the amphoteric surfactant of Example 2 to adjust the pH to a predetermined value.

Each color tone was 4 and the fragrance tone was A. 50 of these
After storing for one month at zero temperature, changes in color tone and aroma tone were examined. The results are shown in Table 3. Table 3 As is clear from this table, adding these acids increases the pH.
When this was adjusted, significant deterioration in color tone and aroma tone was observed after one month.

Claims (1)

[Scope of Claims] 1. Color tone of a cosmetic base material comprising an amide monoamine type amphoteric active agent, characterized in that the pH of the amide monoamine type amphoteric active agent is adjusted to 8 to 10 with a hydrogen salt of a hydroxy polyhydric carboxylic acid. and a method for preventing deterioration of fragrance tone. 2. The method according to claim 1, wherein the hydrogen salt of the hydroxy polycarboxylic acid is a hydrogen salt of citric acid, malic acid, or tartaric acid.