JPH0316324B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for preservative and anti-mold of cosmetics, and more specifically, in order to preservative and anti-mold of cosmetics by blending a preservative and anti-mold, water-soluble alkali metal salts of lactic acid are used in combination with a phenol-based preservative and anti-mold. In particular, the present invention relates to a method for improving the antiseptic and antifungal properties of emulsified cosmetics. In general, cosmetics are repeatedly contaminated with airborne bacteria and microorganisms attached to or resident on the skin during use. As a result of contamination with microorganisms, quality deterioration such as deterioration and deterioration may occur, and even if no significant deterioration or deterioration occurs, a large amount of microorganisms may proliferate. Since one cosmetic product is used intermittently for several months or one to two years, it is not only susceptible to deterioration and deterioration, but also needs to be microbiologically stable from a hygienic standpoint. Therefore, various preservatives and fungicides are added to cosmetics in order to improve their stability against microbial contamination during use. The preservatives and fungicides that are permitted to be blended are extremely safe for the human body, but are somewhat toxic, so the type and amount are regulated. Now that safer cosmetics are desired, what is most needed is to achieve sufficient effects with a small amount of preservatives and fungicides. The present invention makes this possible. In addition, many of the components of cosmetics reduce the effectiveness of preservatives and fungicides, such as inactivation of phenolic preservatives by surfactants, or quaternary ammonium salts by clay minerals. The most well-known example is the adsorption and inactivation of . Furthermore, if the oil blended into cosmetics has a high polarity, the distribution of the phenolic preservative and fungicide will be biased towards the oil, so no effect can be expected unless a large amount is blended. It is well known that the effects of alkali metal salts of organic acids such as benzoic acid and dehydroacetic acid vary greatly depending on the pH of the cosmetic. In this way, the amount of preservatives and fungicides used is limited due to toxicity, and their effectiveness is weakened by the components of cosmetics. Selecting a fungicide is extremely difficult. It is also known that it is most difficult to select a preservative and fungicide for emulsified cosmetics among a wide variety of cosmetics, and the present invention has developed a phenol-based preservative that is specifically effective for this most difficult emulsified cosmetic. The effectiveness of the combined use of a fungicide and an alkali metal salt of lactic acid was discovered. The term "emulsified cosmetics" as used in the present invention refers to all products in which water and oil are emulsified using a nonionic surfactant alone or a combination of a nonionic surfactant and a fatty acid stone. It goes without saying that these emulsified products include those containing clay minerals and pigments. Preservatives and fungicides used in cosmetics include phenol-based agents, quaternary ammonium salts, and anidolic amphoteric agents, but the present invention uses isopropylmethylphenol and P-hydroxybenzoin which have a phenol core. It was specifically discovered in phenol-based preservatives and fungicides represented by acid esters. Among the alkali metal salts of lactic acid that have a remarkable combined effect with this phenolic preservative and antifungal agent, the sodium salt is well known and easily available, but its application to cosmetics is still insufficient. I can't say that. Regarding sodium lactate, there is a description in the makeup original/additional edition that it is ``used as a substitute for glycerin.It also has the property of making O/W type creams finer in texture.'' However, in terms of actual application, It is a raw material that has many problems and is difficult to use. Although it does have a moisturizing effect, it does not have the advantage of usability to the extent that it can be used as a substitute for glycerin, and depending on the product, it may even worsen the stability of some products. In addition, although it is written that O/W type cream has the property of making the texture finer, there is no mention of its actual application, and when it is actually mixed, it does not make the texture finer, but it actually improves the stability. The reality is that there are almost no examples of its application in cosmetics because it seems to be harmful and has fewer advantages compared to other raw materials. The present invention is groundbreaking in that it newly discovered the unique advantages of this raw material. In carrying out the method of the present invention, the amount of alkali metal salt of lactic acid to be used (the amount blended,
The amount added is not particularly limited, but it is sufficient if it is used in an amount of 0.1 to 10.0% by weight based on the water content of the emulsified cosmetic. Although sufficient effects are recognized even at 10.0% by weight or more,
If used in excess of this amount, the stability of the emulsified cosmetic may be impaired, making formulation difficult. Also, 0.1% by weight
It is difficult to clearly confirm the effect of the combined use at less than 20%. In particular, the combination with a significant effect is preferably in the range of 1.0 to 5.0% by weight. It is not clear why alkali metal salts of lactic acid and phenolic preservatives and fungicides have a specific combined effect in emulsified cosmetics, but it is clear that alkali metal salts of lactic acid and phenolic preservatives and fungicides have a specific combined effect in emulsified cosmetics. When examining the effect on distribution, it was confirmed that the amount of preservative and fungicide dissolved in the aqueous phase, which is the outer phase of the O/W emulsion, was reduced. In general, moisturizers such as propylene glycol, which increase the amount of preservatives and fungicides dissolved in the aqueous phase of the outer phase of O/W emulsions, are effective when used in combination with preservatives and fungicides. It is said that there is. Although they are similar moisturizers, alkali metal salts of lactic acid and propylene glycol have completely opposite effects on the distribution of preservatives and fungicides, and as a result they have the same feature in that they enhance the antiseptic and fungicidal effect. This advantage, which is not found in the prior art, has been confirmed and led to the present invention. It goes without saying that other substances that reduce the amount of preservative and fungicide in the aqueous phase of the O/W emulsion do not have the same effect when used in combination as an alkali metal salt of lactic acid. Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples, and the present invention is not limited to these Examples. Needless to say, the scope of the present invention also covers such cases. Example 1 In case of dilute emulsion Polyoxyethylene oleyl ether type (15 moles of ethylene oxide added) activator 3%, purity
99.5%, ethanol 5%, olive oil 5%, cetyl alcohol 1%, methyl p-oxybenzoate
0.1-0.5%, and add the specified amount of sodium lactate to this 0.1%
~5% was added, and ion exchanged water was further added to make it 100%. A small amount of suspension (10 ⁶ /ml) of the yeast Candida albicans (10 6 /ml) pre-cultured for 48 hours was added to this solution, and the final concentration was adjusted so that 10 ⁴ /ml of yeast was inoculated. The number of viable yeast cells was measured over time. The results are shown in Table 1.

[Table] The combined effect of methyl p-oxybenzoate and sodium lactate was observed. That is, no effect is observed with only 5% sodium lactate (5.8% based on the total water content). Also, methyl p-oxybenzoate 0.1
% alone has no effect at all. However, it was confirmed that when 0.1 to 5.0% of sodium lactate was combined with 0.1% of methyl p-oxybenzoate, the effect increased significantly as the amount of the combination increased. Methyl P-oxybenzoate 0.3% or 0.5
% combination, the effect of combined use of sodium lactate was similarly confirmed. To obtain the same effect as 0.5% methyl P-oxybenzoate, if using 0.3% methyl P-oxybenzoate, use 1% sodium lactate together, or if using 0.1% sodium lactate 2% methyl P-oxybenzoate. It turns out that it is better to use % together. Also, methyl P-oxybenzoate 0.3%, sodium lactate 2% and methyl P-oxybenzoate 0.1%.
%, and a combination with 5% sodium lactate has shown similar effects. In this way, the fact that the same effect can be obtained with half or less of the preservative is an epoch-making achievement not found in the prior art. Example 2 The combined effect of sodium lactate and butyl P-oxybenzoate when mixed into an emulsion as in Example 1 was evaluated using the yeast Candida albicans.
albicans). The composition of the emulsion is 10% liquid paraffin, 10% isopropyl myristate, 2% cetyl alcohol, 4% cetyl ether added with 20 moles of polyoxyethylene, 6% glycol, an appropriate amount of mucilage, and 0.1 to 0.1 to butyl P-oxybenzoate. 0.5%, sodium lactate 0.1-5%,
Deionized water was added to this to make it 100%. As in Example 1, adjustments were made so that 10 ⁴ yeast cells were inoculated per 1 g of emulsion, and the number of viable yeast cells was measured over time. The results are shown in Table 2.

[Table] Symbols: Same as Table 1.
The combined effect of butyl P-oxybenzoate and sodium lactate was observed. Example 3 Using the same base as in Example 2, the effect on Pseudomonas aeruginosa was investigated when 6% glycerin was added instead of glycol.

【table】

[Table] Symbols: Same as Table 1.
Similar to the effect on yeast, the combined use of preservatives and potassium lactate is also effective against Pseudomonas aeruginosa. In the case of Examples 2 and 3, Example 1
Similarly, it was confirmed that by using an alkali metal salt of lactic acid in combination, the amount of preservatives can be reduced to about half. Example 4 5% liquid paraffin, 8% reduced lanolin, 4% stearic acid, 2% cetyl alcohol, 2.5% sorbitan monostearate with 20 moles of polyoxyethylene, 0.3% potassium hydroxide, 7% glycol in appropriate amounts. , ethyl P-oxybenzoate 0.1-0.5%, sodium lactate 0.5-5%, and ion-exchanged water was added to make 100%. This emulsion was inoculated with ¹⁰⁴ mold spores/g,
The number of surviving mold spores was measured over time, and the effect of combined use of ethyl P-oxybenzoate and sodium lactate was investigated. The results are shown in Table 4.

【table】

[Table] Similar to the above example, the combined effect of ethyl P-oxybenzoate and sodium lactate was observed.

Claims (1)

[Claims] 1. A preservative and anti-mold method for emulsified cosmetics, which comprises using at least one water-soluble alkali metal salt in combination with a phenolic preservative and anti-mold agent.