Aqueous moisturizing cosmetic liquid

Abstract

To provide a water-retaining cosmetic liquid free from an unpleasant sticky feeling, and to provide a water-retaining cosmetic liquid that enables long-term storage at room temperature without using synthetic preservatives or bactericidal agents and is safe and reassuring.SOLUTION: The present invention is based on an aqueous solution having a glycerin concentration of 22 to 40 t% and a water activity value of 0.90 or less, and suppresses proliferation of microorganisms to enable long-term storage at room temperature. As a result, it becomes possible to provide a safe and reassuring moisturizing cosmetic liquid having no unpleasant sticky feeling and containing no synthetic preservatives or bactericidal agents.

Description

[Technical Field]

[0001] The present invention relates to an aqueous moisturizing cosmetic liquid that can be used on the whole body. [Background technology]

[0002] Conventional moisturizing cosmetics include (1) oily cream products and (2) liquid products containing dissolved glycerin and various functional substances, both of which contain synthetic preservatives and disinfectants that are unsafe for the human body. (1) Oily cream products leave a characteristic slimy, sticky feeling after use, and do not provide a refreshing feeling. If applied to the hands, they can cause discomfort to others when they come into contact with door handles or refrigerator handles. When driving, there is a risk of steering incorrectly due to the slimy feeling, and when cooking, there is a risk of slipping when holding utensils or of harmful substances being mixed into the food being handled. (2) Liquid products also have similar problems regarding harmful ingredients. For this reason, we felt the need for moisturizing cosmetics that are light and refreshing, yet safe and secure, and developed this water-based moisturizing lotion. [Prior art documents] [Patent documents] [Patent documents] Patent No. 5700627

[0003] It is well known that glycerin is effective in moisturizing the skin. However, if the concentration of the aqueous solution is too high, its hygroscopic properties may cause dryness of the skin when applied. Patent No. 5700627 states that general moisturizing cosmetics have problems in terms of effectiveness and stickiness, and that the solution to these problems is to use specific polyglycerins (triglycerin, tetraglycerin, etc.) at a specified concentration. Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional moisturizing cosmetics are either (1) oily cream products or (2) liquid products, both of which contain synthetic preservatives and disinfectants that are unsafe for the human body. Furthermore, oily cream products have a characteristic slimy texture, which can cause various problems after use, as mentioned above. Liquid products generally contain substances that pose safety concerns, such as preservatives, but products that do not contain such substances are ideal as moisturizing cosmetics. Conventional moisturizing cosmetics contain disinfectants and preservatives, which pose a risk of accidental ingestion by young children and the elderly, or oral ingestion if the product is left on while cooking. For this reason, there has been a demand for moisturizing cosmetics that are made only from safe and reliable ingredients and do not contain disinfectants or synthetic preservatives. [Means for solving the problem]

[0005] The base ingredients for this moisturizing cosmetic product, which combines moisturizing effects with safety, are water and glycerin. The system is free of synthetic preservatives, disinfectants, and other preservatives, and the concentration is set to a water activity value of Aw 0.90 (approximately 35% by weight for glycerin alone), allowing for long-term storage at room temperature. To further enhance functionality, an appropriate amount of citric acid, a safe food additive that maintains a mild acidity that is beneficial for the skin, has anti-inflammatory properties, and provides peeling effects, was added. In addition, when sake, which contains the skin-beautifying ingredient α-EG, was added as a partial replacement for glycerin, the fragrance was enhanced as well as the smooth, refreshing feeling. [Effects of the Invention]

[0006] Glycerin was added to water to a concentration of 35 wt% (650 g water, 350 g glycerin), and 7.5 g of citric acid was added and dissolved. When the solution was applied to the hands, it provided an exceptional moisturizing feeling without stickiness. It allowed for a smooth grip on knives, table tennis rackets, baseball bats, etc. When I tried it on my entire body, including my scalp, hair, face, neck, hands, arms, chest, back, abdomen, legs, and soles of the feet, I found that it provided comfortable moisturizing everywhere. DETAILED DESCRIPTION OF THE INVENTION

[0007] Below is an example of the development of safe and secure moisturizing cosmetics that are non-sticky, comfortable to use, and do not contain any antiseptics such as disinfectants or preservatives. [Example]

[0008] Glycerin has a high viscosity and stickiness at room temperature. To reduce this, it needs to be diluted with water in cosmetics. However, if it is diluted too much, it will spoil and become difficult to store for a long time at room temperature. The glycerin concentration corresponding to a water activity value Aw of 0.90, which is considered to be the limit of growth for general bacteria, is approximately 35 weight percent (data from a glycerin manufacturer). A 35 weight percent aqueous solution of glycerin is not sticky at room temperature, so this solution was used as the base for the moisturizing cosmetic composition of the present invention. [Example]

[0009] Dissolve 350g of glycerin and 7.5g of citric acid in 650g of water. When I applied an appropriate amount to my hands, I was able to confirm that it had a moisturizing effect without any stickiness. I also confirmed that it was suitable for the hair, scalp, neck, shoulders, arms, back, buttocks, lower legs, toes, and soles of the feet, demonstrating that it can be applied to the entire body. Adding less than 1g (0.1% by weight) of citric acid did not produce any noticeable effect, and adding more than 25g (2.5% by weight) caused too much irritation to the skin. When we considered using a similar substance, L-ascorbic acid (vitamin C), as a substitute for citric acid, we found that the solution began to brown within a few days at room temperature, and therefore it was determined that its use was undesirable. [Example]

[0010] A test was conducted on a mixture of 300g of zero-sugar sake (13-14% alcohol, approximately 10.7% by weight), 310g of glycerin, 390g of water, and 7.5g of citric acid, and the same results as in Example 1 were obtained. This blend was calculated and determined to give an Aw value of 0.90. The result was a strong aroma of sake and a refreshing taste. [Example]

[0011] A test was conducted on a mixture of 773g of sugar-free sake (13-14% ABV, 10.7% alcohol by weight), 227g of glycerin, and 7.5g of citric acid, and the results were comparable to those of Example 1. This blend was calculated to achieve an Aw value of 0.90, depending on the amount of water contained in the sake. Compared with Example 2, the alcoholic aroma was stronger, and the smooth and refreshing feeling was also stronger. [Example]

[0012] The solutions prepared in Example 1, Example 2, and Example 3 above were mixed with 0.2% thawed drippings from frozen meat (beef) and frozen fish (pacific saury), placed in glass containers, loosely covered to allow air to circulate, and left at room temperature for a long period of time (180 days). No spoilage was observed. This demonstrates that all three solutions can be stored at room temperature for long periods of time. [Example]

[0013] The solution prepared in the same manner as in Example 1 above was diluted with water and tested in the same manner as in Example 4. The dilution ratios were 5% (stock solution 95: water 5), 10% (stock solution 90: water 10), and 15% (stock solution 85: water 15). After 90 days at room temperature, no decay was observed in the 5% diluted solution, but slight decay was observed in the 10% diluted solution and severe decay in the 15% diluted solution. A similar test was performed on a 35% solution of glycerin alone without the addition of citric acid, and the same results were obtained. This confirmed that the spoilage inhibitory effect was dominated by water activity rather than acidity. [Industrial Applicability]

[0013] This spoilage prevention technology, which does not require synthetic preservatives or disinfectants, has the potential to be used in a wide range of fields, including cosmetics manufacturing.

Claims

1. A moisturizing cosmetic liquid based on a glycerin solution having a water activity value Aw of 0.90 or less.

2. A moisturizing cosmetic liquid obtained by adding 0.1 to 2.5% by weight of citric acid to the solution of claim 1.

3. A moisturizing lotion in which part of the glycerin in claim 1 and claim 2 is replaced with alcohol such as sake.

4. The moisturizing cosmetic liquid according to any one of claims 1 to 3, which does not contain any synthetic preservatives or antiseptics such as bactericides.