JPS6026765B2 - 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 cosmetics made of an amide monoamine type amphoteric surfactant.

In more detail, the present invention relates to a method for preventing deterioration of the color tone and fragrance tone of the fragrance cone base material by adjusting the pH to 8 to 10 with a hydroxy polycarboxylic acid. In recent years, amidomonoamine type amphoteric active agents have come to be used as base materials for fragrance products such as shampoos, conditioners, and liquid facial soaps. -13, so when used as a base material for cosmetics, it is necessary to adjust the pH to a lower range.

Conventionally, the pH of such amidomonoamine type amphoteric surfactants was adjusted using inorganic acids such as hydrochloric acid and sulfuric acid, but products with pH adjusted in this way may be exposed to sunlight for long periods of time or stored at high temperatures. Since it causes significant coloration and deterioration of fragrance tone, it tends to reduce its commercial value as a base material for cosmetics. The present inventors investigated to solve this problem and found that if the - of the amidomonoamine type amphoteric activator is adjusted with a hydroxy polyhydric carboxylic acid, the color tone and fragrance tone of the activator will not change over time. It has been discovered that the activator can be advantageously used as a base material for cosmetics, and the present invention has been completed.

That is, the present invention is a method for preventing deterioration of the color tone and fragrance of a cosmetic base material made of an amide monoamine type amphoteric active agent, which is characterized by adjusting the pH of the amide monoamine type amphoteric active agent to 8 to 10 with a hydroxy polyhydric carboxylic acid. The present invention provides a method.

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 imidazoline obtained by dehydration condensation of and diamine.

As the hydroxy polycarboxylic acid used for pH adjustment in the present invention, citric acid, malic acid, and tartaric acid are particularly 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 1 to 8% by weight of the amphoteric active agent.
That's about it. To adjust the pH of the amphoteric surfactant with a hydroxy polycarboxylic acid, the amphoteric surfactant is placed in a pH adjustment tank, the hydroxy polycarboxylic acid is added thereto in the form of a powder or an aqueous solution, and the mixture is stirred at a temperature of 20 to 8,000 for several hours.

The amide monoamine type amphoteric surfactant whose pH has been adjusted to 8 to 10 according to the present invention does not deteriorate in color tone or fragrance even if stored at 5000℃ 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 activator will be significantly colored and produce a strange odor due to long-term storage, while if adjusted higher than 11, the fragrance will deteriorate, so the pH should be adjusted between 8 and 10.
Must be within the range of In addition, other organic acids other than 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 tone as hydroxy polycarboxylic acids do.

Next, the present invention will be explained by examples.

Example 1 1 mole of N-lauroyl-N'-8-hydroxyethylethylenediamine obtained by dehydration condensation from lauric acid and aminoethyl ethanolamine and 1 mole of ethyl acrylate were mixed in a stirrer and at a certain temperature. The mixture was placed in two four-necked flasks equipped with a meter and a condenser, and reacted at 80 o'clock for 4 hours to obtain a pale yellow transparent product.

520 g of water and 1.1 mol of sodium hydroxide were added, and the mixture was further saponified at 80 qC for 2 hours. The product is 40% N
-Lauroyl-N'-8hydroxyethyl-N'-sodium carboxyethyl ethylene diamine.This aqueous solution has a pH of 12. The color tone (Gardner color) was 4, and the fragrance tone was good ■. Powders of citric acid, malic acid, and tartaric acid were added to this amphoteric activator (40% aqueous solution) at room temperature, and the mixture was stirred for 1 hour until the pH reached 6.
-11 and stored at 50 qo for 1 month to examine 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 no wind adjustment was performed, the color tone after one month under the same conditions was 4, and the fragrance tone was B to C.
Table 1 Measurement method: Measurement was carried out in accordance with ASTM-D15441 using a Gardner-Liege colorimeter, filling a sample into a Gardner 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.

Table 2 Fragrance tone indications A, B, and C indicate the following states.

A: Good with no change in fragrance B: Change in fragrance, usable C: Significant change in fragrance, unusable As is clear from the above results, pH is 8 to 10 No change in color tone or aroma tone was observed within this range, and the usefulness of the amphoteric active agent as a base material for perfumery products is satisfactory.

Example 2 Example 1 except that acid-proofing oil was used instead of lauric acid.
An amidomonoamine amphoteric activator was obtained in the same manner as above.

The pH of this amphoteric activator was 12.0 (Gardner color) 4-, aroma A. After adding 1% by weight of citric acid to adjust the FH to 10, it was stored at 50oo for 1 month. As a result, the color tone was 4 and the fragrance tone was A. Example 3 2-alkyl-N-8 hydroxyethyl imidazoline was produced by dehydration reaction of 2 moles of coconut fatty acid and aminoethylethanolamine, and 1 mole of the product, 1.5 moles of ethyl acrylate and 2 moles of water were produced. 0 mol was placed in the same flask as in Example 1 and reacted at 8000 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 80 qo 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 25 qo.
12. The color tone (Gardner color) was 4-, and the fragrance tone was A. 1. each of citric acid was added to the aqueous solution at room temperature. Round weight%
and 4% by weight, and after adjusting the pH to 10 and 8,
It was stored for 1 month at 50qo. The results were 4 for all color tones and A for all aromas, and no deterioration was observed in either color or aroma. Example 4 N-lauroyl-N'-6 hydroxyethylethylenediamine was ampholyzed with sodium monochloroacetate to obtain N-lauroyl-N'-8hydroxyethyl-N'-sodium carboxymethylethylenediamine.

Adding citric acid to an aqueous solution (pHil) of the product to make p
Adjusted to H8. The color tone (Gardner color) at this time was 4, and the aroma tone was A. When this was stored at 50oo for one month and examined, there was no change in color tone or aroma tone. Example 5 Stearic acid was used instead of lauric acid and the amount of water was 102
A 30% aqueous solution of N-stearoyl-N-Bhydroxyethyl-N'-sodium carboxyethyl ethylene diamine was obtained in the same manner as in Example 1 except that step 8 was removed.

The aqueous solution has a pH of 25.0 and 12.5, a color tone (Gardner color) of 4, and a fragrance tone of A. When malic acid was added to adjust the pH to 10 at room temperature and the product was stored at 50 qo for one month, the color changed and the aroma was A. Reference Example The acid shown in Table 3 was added to the amphoteric surfactant of Example 3 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 in qo, 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 and fragrance 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 hydroxy polycarboxylic acid. How to prevent deterioration. 2. The method according to claim 1, wherein the hydroxy polycarboxylic acid is citric acid, malic acid or tartaric acid.