Moisturizing cosmetic liquid

Abstract

[Problem] (1) To develop / provide a moisturizing cosmetic liquid that is free of sticky and unpleasant feeling; and (2) to develop / provide a moisturizing cosmetic liquid that is prepared without using any synthetic preservative or bactericide, can be preserved for a long period of time at ordinary temperature, and is safe and secure. [Solution] In this moisturizing cosmetic liquid, an aqueous solution having a glycerin concentration of 22-40 t% and a water activity value of 0.90 or less is used as a base. The moisturizing cosmetic liquid is resistant to bacterial proliferation, and can be preserved for a long period of time at ordinary temperature. As a result, it becomes possible to provide a moisturizing cosmetic liquid which is free of sticky and unpleasant feeling, does not contain a synthetic preservative, a bactericide or the like, and is safe and secure.

Description

[Replenishment under Rule 26 03.07.2025] Moisturizing lotion

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

[0002] Conventional moisturizing cosmetics include (1) oil-based cream products and (2) liquid products containing dissolved glycerin or functional substances. Both contain synthetic preservatives, disinfectants, and other preservatives that are unsafe for the human body. (1) Oil-based cream products leave a characteristic slimy, sticky feeling after use and do not provide a refreshing, dry feeling. When applied to the hands, door handles and refrigerator handles can be unpleasant for others. 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 with harmful substances. Therefore, we felt the need for a moisturizing cosmetic that is both smooth and refreshing and safe, and developed this aqueous moisturizing lotion.

[0003] It is well known that glycerin is effective in moisturizing the skin. However, if the aqueous solution is too concentrated, its moisturizing effect may cause dryness when applied to the skin. Patent No. 5700627 states that general moisturizing cosmetics have problems in terms of effectiveness and stickiness, and that the use of specific polyglycerins (triglycerin, tetraglycerin, etc.) at specified concentrations is effective in solving this problem.

[0004] Conventional moisturizing cosmetics, whether they be (1) oil-based cream products or (2) liquid products, contain synthetic preservatives, bactericides, and other preservatives that pose safety concerns for the human body. Furthermore, oil-based cream products have a characteristic slimy texture and present various post-application issues, as described above. Liquid products generally contain preservatives and other substances with safety concerns, but ideal moisturizing cosmetics would be those free of such substances. Conventional moisturizing cosmetics contain bactericides and preservatives, posing a risk of accidental ingestion by young children and the elderly, or oral ingestion when cooking with the product applied. Therefore, moisturizing cosmetics composed solely of safe and reliable ingredients, free of bactericides and synthetic preservatives, are desired. Solution to the Problem: A moisturizing cosmetic that combines moisturizing effects and safety is formulated with a base of water and glycerin. The system is free of synthetic preservatives, bactericides, and other preservatives, and the concentration is set to achieve a water activity value (Aw) of 0.90 or less (approximately 35% by weight for glycerin alone), allowing for long-term storage at room temperature. To enhance and improve functionality, an appropriate amount of citric acid, a safe food additive with skin-friendly weak acidity, anti-inflammatory properties, and peeling properties, was added. Furthermore, 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 feel.

[0005] Glycerin was added to water to a concentration of 35 wt% (650g water, 350g glycerin), and 7.5g of citric acid was added and dissolved. When the same liquid was applied to the hands, a non-sticky, exceptionally moisturizing feeling was obtained. It was possible to grip knives, table tennis rackets, baseball bats, etc. without slipping. When applied to the entire body, including the scalp, hair, face, neck, hands, arms, chest, back, abdomen, legs, and soles of the feet, it was confirmed that the product provided comfortable moisturizing everywhere. "Modes for Carrying Out the Invention" Below is an example of the development of a safe and secure moisturizing cosmetic product that is non-sticky, comfortable to use, and does not contain any antiseptics such as disinfectants or preservatives.

[0006] Glycerin has a high viscosity at room temperature and feels sticky. To reduce this, it must be diluted with water in cosmetic liquids. On the other hand, if it is diluted too much, it will spoil and become difficult to store for long periods at room temperature. The glycerin concentration corresponding to a water activity value Aw of 0.90, considered the limit for bacterial growth, is approximately 35 weight percent (data from a glycerin manufacturer). Because a 35 weight percent aqueous solution of glycerin is not particularly sticky at room temperature, this solution was used as the base for the moisturizing cosmetic liquid composition of the present invention.

[0007] Dissolve 350g of glycerin and 7.5g of citric acid in 650g of water. When applied to the hands, a moderate amount was observed, with no stickiness and a moisturizing effect. The product was also confirmed to be suitable for the hair, scalp, neck, shoulders, arms, back, buttocks, lower legs, toes, and soles, demonstrating its suitability for use on the entire body. Adding less than 1g (0.1% by weight) of citric acid produced no noticeable effect, while adding more than 25g (2.5% by weight) was too irritating to the skin. When L-ascorbic acid (vitamin C), a similar substance, was examined as a citric acid substitute, browning of the solution was observed within a few days at room temperature, and its use was deemed undesirable.

[0008] A test was conducted on a mixture of 300g of sugar-free sake (13-14% alcohol, approximately 10.7% by weight of alcohol), 310g of glycerin, 390g of water, and 7.5g of citric acid, and the results were comparable to those of Example 1. The blend was calculated to achieve an Aw value of 0.90. The result was a strong sake aroma and a refreshing taste.

[0009] 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. The water content of this mixture was calculated to achieve an Aw value of 0.90, depending on the moisture content of the sake. Compared to Example 2, the sake aroma was stronger, and the smooth, refreshing feel was also stronger.

[0010] The solutions prepared in Examples 1, 2, and 3 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 specifications can be stored at room temperature for a long period of time.

[0011] The solution prepared in the same manner as in Example 1 above was diluted with water and subjected to the same test as in Example 4. The dilution ratios were 5% (95 parts stock solution: 5 parts water), 10% (90 parts stock solution: 10 parts water), and 15% (85 parts stock solution: 15 parts water). After 90 days at room temperature, no spoilage was observed in the 5% diluted solution, but slight spoilage was observed in the 10% diluted solution, and severe spoilage was observed in the 15% diluted solution. A similar test was also 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 inhibition effect is dominated by water activity rather than acidity.

[0012] Since it is possible to prevent spoilage in cosmetic manufacturing without using synthetic preservatives or disinfectants, it has the potential to be used in a wide range of fields, not just cosmetics.

Claims

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

2. A moisturizing cosmetic liquid in which 0.1 to 2.5% by weight of citric acid is added to the solution of claim 1.

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

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