JP-2026075202-A - Water-in-oil emulsion cosmetic

Abstract

[Problem] To provide a water-in-oil emulsion cosmetic using lecithin, a naturally derived emulsifier, as the main emulsifier. [Solution] An oil-in-oil emulsion cosmetic is used, which contains the following components (A) to (D), with a content of component (A) of 0.3 to 10% by mass, a content of component (B) of 0.2 to 6% by mass, and a content of component (C) of 15 to 95% by mass. According to the present invention, an oil-in-oil emulsion cosmetic can be obtained without requiring emulsifiers other than lecithin, so an oil-in-oil emulsion cosmetic that uses only naturally derived emulsifiers can be provided, and an oil-in-oil emulsion cosmetic with excellent feel can be provided. (A) Lecithin (B) Dextrin fatty acid ester or/and inulin fatty acid ester (C) Oil (D) Water [Selection Diagram] None

Inventors

• 岩崎 和弘
• 勝間田 祐貴
• 大橋 幸浩

Assignees

• 日本精化株式会社

Dates

Publication Date

20260508

Application Date

20241022

Claims (5)

1. An oil-in-oil emulsion cosmetic containing the following components (A) to (D), wherein the content of component (A) is 0.2 to 10% by mass, the content of component (B) is 0.2 to 6% by mass, and the content of component (C) is 15 to 95% by mass. (A) Lecithin (B) Dextrin fatty acid ester and/or inulin fatty acid ester (C) Oil (D) Water
2. The water-in-oil emulsion cosmetic according to claim 1, wherein component (B) is one or more selected from dextrin myristate, dextrin palmitate, dextrin isopalmitate, (palmitic acid/ethylhexanoic acid) dextrin, (palmitic acid/stearic acid) dextrin, (palmitic acid/hexyldecanoic acid) dextrin, dextrin stearate, dextrin isostearate, dextrin oleate, inulin myristate, inulin palmitate, inulin stearate, and inulin isostearate.
3. Furthermore, the water-in-oil emulsion cosmetic composition according to claim 1 is characterized by containing sterols as component (E).
4. Furthermore, the water-in-oil emulsion cosmetic composition according to claim 1 is characterized by containing an inorganic salt as component (F).
5. An oil-in-oil emulsion cosmetic composition according to any one of claims 1 to 4, characterized in that it substantially does not contain emulsifiers other than component (A).

Description

This invention relates to a water-in-oil emulsion cosmetic containing lecithin. In the cosmetics field, oil-in-water (O/W) and water-in-oil (W/O) emulsions are widely used as formulations due to their convenience in providing both water-based and oil-based components to the skin and hair, and their ability to provide desired texture and usability. Of these, water-in-oil (W/O) emulsions, taking advantage of their characteristic of having a continuous oil phase, are used in a variety of applications including skincare, makeup, cleansing, sunscreen, and haircare. While the use of emulsifiers is essential for emulsion production, generally, lipophilic emulsifiers with an HLB of around 2-6 are used in the production of water-in-oil emulsions. However, most lipophilic emulsifiers used in cosmetics are obtained through chemical synthesis. On the other hand, in recent years, the cosmetics field has seen a growing demand for naturally derived emulsifiers from consumers' preference for natural products, environmental impact reduction, and contributions to a sustainable society. Furthermore, lipophilic emulsifiers are not always sufficient in terms of texture and feel. Lecithin is a general term for mixtures mainly composed of various phospholipids obtained from animals or plants, and is used in various fields as a naturally derived emulsifier without concerns about skin irritation. Lecithin possesses excellent physiological effects such as moisturizing, whitening, collagen production promotion, and irritation reduction, as well as a unique and superior feel not found in other emulsifiers. In the cosmetics field, lecithin is generally used as an emulsifier in oil-in-water emulsion cosmetics, including liposomes. While its use in water-in-oil emulsion cosmetics has also been attempted, it is generally used auxiliaryly with lipophilic emulsifiers (e.g., Patent Documents 1-3), and water-in-oil emulsion cosmetics with lecithin as the main emulsifier have not been known until now. Japanese Patent Publication No. 2010-001259Japanese Patent Publication No. 2011-068571Japanese Patent Publication No. 2017-078055 The water-in-oil emulsion cosmetic composition of the present invention is characterized by containing the following components (A) to (D). (A) Lecithin (B) Dextrin fatty acid ester and/or inulin fatty acid ester (C) Oil (D) Water The lecithin component (A) used in this invention is used as the main emulsifier in a water-in-oil emulsion cosmetic. In this invention, "used as the main emulsifier" means that the content of component (A) in the total emulsifiers contained in the water-in-oil emulsion cosmetic is 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more. Specific examples of component (A) of the present invention include lecithin obtained from plants such as soybeans, rapeseed, sunflower, safflower, peanuts, cottonseed, corn, rice, and barley, as well as egg yolks, and their hydrogenated forms. The lecithin may be liquid lecithin containing an oily component. Of these, lecithin obtained from soybeans or sunflowers is preferred from the viewpoint of availability, and lecithin obtained from soybeans is most preferred. While commercially available lecithins have varying phosphatidylcholine (PC) content depending on their degree of purification, any PC content can be used in the present invention. From the viewpoint of maximizing the effects of the present invention, a PC content of 15 to 60% by mass is preferred, and 20 to 50% by mass is more preferred. From the viewpoint of fully exhibiting the effects of the present invention, the amount of component (A) incorporated into the water-in-oil emulsion cosmetic is preferably 0.2 to 10% by mass, more preferably 0.3 to 8% by mass, and most preferably 0.4 to 6% by mass. The dextrin fatty acid ester and inulin fatty acid ester of component (B) used in this invention are commonly used as oil thickeners in the cosmetics field. In this invention, while it is difficult to form a water-in-oil emulsion with component (A) alone, by using component (A) and component (B) in combination, it becomes possible to form a water-in-oil emulsion with component (A) as the main emulsifier. Specific examples of component (B) of the present invention include dextrin fatty acid esters, which are esterified products of dextrin and linear or branched saturated or unsaturated fatty acids having 8 to 22 carbon atoms. More specifically, these include dextrin caprylate, dextrin caprate, dextrin ethylhexanoate, dextrin laurate, dextrin myristate, dextrin palmitate, dextrin isopalmitate, (palmitic acid/ethylhexanoate) dextrin, (palmitic acid/stearic acid) dextrin, (palmitic acid/hexyldecanoic acid) dextrin, dextrin stearate, dextrin isostearate, dextrin oleate, and dextrin behenate. Inulin fatty acid esters are esterified products of inulin with a linear or branched saturated or unsaturated fatty acid having 8 to 22 carbon atoms. More specifically, examples incl