JP7141971B2 - gel cosmetics - Google Patents

Description

TECHNICAL FIELD The present invention relates to gel cosmetics.

Cholesteric liquid crystals are a type of thermotropic liquid crystals, and are mainly composed of cholesterol derivatives and the like. In cholesteric liquid crystals, the direction of the molecular alignment that forms the liquid crystal structure is gradually twisted, resulting in a helical layered structure. ) are known to exhibit Therefore, when a cholesteric liquid crystal is added to a cosmetic, beautiful interference light (structural color) can be seen, making the cosmetic excellent in appearance. In particular, when blended in a gel cosmetic, its effect is remarkable (see Patent Documents 1 to 4). Liquid crystals composed of various cholesterol derivatives are on the market for the purpose of blending in cosmetics.

In addition, cosmetics containing cholesteric liquid crystals have the effect of suppressing skin water evaporation and keeping the skin moist (see Non-Patent Document 1 and Patent Document 5).
In order to disperse and stably retain cholesteric liquid crystals in cosmetics, a polymer thickener is often blended as a base. A gel-like cosmetic containing a cholesteric liquid crystal and a polymer thickener has a beautiful appearance, an excellent skin care effect, and excellent storage stability of the cosmetic. According to Patent Document 6, when dispersing cholesteric liquid crystals in cosmetics, if the cholesteric liquid crystals are dispersed in a size of 0.1 to 10 mm, the coloring of the liquid crystals is beautiful, and the dispersion of the liquid crystals that can be visually recognized can be visually recognized. It is described that it will be of interest to However, such preparations disperse the viscous cholesteric liquid crystals with a relatively large particle size, resulting in significant stickiness when applied to the skin. In addition, the polymer thickener used as a base also has the drawback of producing a peculiar sticky feeling when it is applied to the skin when applied.

Patent Literature 7 proposes a cosmetic that contains water-insoluble particles to improve color development while suppressing the blending amount of cholesteric liquid crystals to 0.5 to 20% by weight, and to suppress stickiness. However, by suppressing the amount of cholesteric liquid crystal, this cosmetic has a fresh feel when applied to the skin as an aqueous gel. has not been resolved.

On the other hand, it is known that by blending various polyoxyalkylene glyceryl ethers, the stickiness of water-soluble polymers and water-swelling clay minerals blended in gel cosmetics can be suppressed (Patent Documents 8 and 9). ). In order to suppress such sticky feeling, those containing a polyalkylene group having a long alkyl chain portion, such as a polyoxypropylene group and a polyoxybutylene group, are particularly effective. Moreover, it is known that polyoxyethylene glyceryl ether containing no polyoxypropylene group or polyoxybutylene group is suitable for warming cosmetics (see Patent Documents 10 and 11).
However, the effect and optimal amount of blending of polyoxyethylene glyceryl ether in gel-like cosmetics in which cholesteric liquid crystals are dispersed have not been clarified.

JP-A-01-211512 JP-A-01-242690 JP-A-02-191208 JP-A-02-200607 JP-A-03-034907 JP 2014-198706 A JP 2013-082633 A JP 2013-023455 A JP 2013-023456 A Japanese Patent Application Laid-Open No. 2017-128524 Japanese Patent Application Laid-Open No. 2001-072544

FRAGRANCE JOURNAL 1990-7 P111-114

An object of the present invention is to provide a gel-like cosmetic containing a cholesteric liquid crystal, which has a beautiful appearance, does not feel sticky when used, and has high moisturizing properties.

The main configuration of the present invention is as follows.
1. A gel cosmetic containing the following (A), (B) and (C).
(A) carboxyvinyl polymer and/or acrylic acid/methacrylate alkyl copolymer (B) polyoxyethylene glyceryl ether (C) cholesteric liquid crystal2. (C) A transparent or translucent gel-like composition in which the cholesteric liquid crystal contains (A) a carboxyvinyl polymer and/or an acrylic acid/methacrylate alkyl copolymer and (B) a polyoxyethylene glyceryl ether as constituent components. 1. The gel-like cosmetic according to 1, which is dispersed.
3. (C) The gel-like cosmetic according to 1 or 2, wherein the cholesteric liquid crystal is a mixture containing at least dihydrocholesteryl oleate, cholesteryl nonanoate, dihydrocholesteryl butyrate, cholesteryl butyrate, and phytosteryl oleate.
4. (B) The gel-like cosmetic according to any one of 1 to 3, wherein the total number of added moles of polyoxyethylene groups in the polyoxyethylene glyceryl ether is 7 to 31.
5. 5. The gel cosmetic according to any one of 1 to 4, which has a viscosity of 5,000 to 60,000 mPa·s when measured with a Brookfield viscometer.
6. (B) 0.5 to 10% by mass of polyoxyethylene glyceryl ether; and (C) 0.1 to 5% by mass of cholesteric liquid crystal.
7. A method for producing a cholesteric liquid crystal-containing gel-like cosmetic comprising the following steps.
(1) At least one water solution selected from (A) a carboxyvinyl polymer and an alkyl acrylic acid/methacrylate copolymer whose viscosity is adjusted to be 1000 to 3000 mPa s when measured with a Brookfield viscometer a step of dispersing cholesteric liquid crystals in a transparent or translucent gel composition containing a polyoxyethylene glyceryl ether and (B) polyoxyethylene glyceryl ether as constituent components.
(2) Next, a step of neutralizing the composition obtained in step (1) with a basic compound and increasing the viscosity to 5000 to 60000 mPa·s when measured with a Brookfield viscometer.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a gel-like cosmetic having a peculiarly beautiful appearance in which cholesteric liquid crystals are dispersed, and having excellent moisturizing feeling without stickiness.

4 is an image obtained by observing the liquid crystal of the gel-like cosmetic of Example 4. FIG. The brightly shining oval in the figure is the liquid crystal. 4 is an image obtained by observing the liquid crystal of the gel-like cosmetic of Example 2. FIG. The brightly shining oval in the figure is the liquid crystal. 4 is an image obtained by observing the liquid crystal of the gel-like cosmetic of Comparative Example 5. FIG. The brightly shining liquid crystal is hardly observable. 4 is an image obtained by observing the liquid crystal of the gel-like cosmetic of Comparative Example 11. FIG. The brightly shining liquid crystal is hardly observable.

As described above, the gel-like cosmetic of the present application exhibits a beautiful structural color due to the cholesteric liquid crystal being appropriately dispersed in the transparent or translucent gel-like composition. In addition, the sticky feeling peculiar to gel-like cosmetics containing cholesteric liquid crystals can be eliminated, and the cosmetic can be used with a good feeling. In the present specification, the term "gel composition (or gel base)" does not contain cholesteric liquid crystals, and a gel composition in which cholesteric liquid crystals are dispersed is called a gel cosmetic. distinguish. In the present invention, the term "transparent to translucent" means that 18-point type can be clearly read when a cylindrical glass or PET container with a diameter of 3.5 cm is filled with cosmetic material and visually observed from the side.
The compounding components and manufacturing process are described below.

(A) Carboxyvinyl Polymer and/or Alkyl Acrylic Acid/Methacrylate Copolymer In the gel-like cosmetic of the present invention, the base material of the gel composition is selected from carboxyvinyl polymer and alkyl acrylic acid/methacrylate copolymer. contains one or more water-soluble polymeric compounds. The amount of the carboxyvinyl polymer and/or the alkyl acrylate/methacrylate copolymer to be blended can be appropriately changed depending on the viscosity of the gel cosmetic, but it is 0.03 to 1% by mass, more preferably 0.00% by mass. It is preferably 1 to 0.5% by mass. When two types are blended, the total amount is preferably 0.03 to 1% by mass, more preferably 0.1 to 0.5% by mass. If the amount is less than 0.03% by mass, there is a possibility that sufficient viscosity cannot be obtained. If the amount is more than 1% by mass, the feeling of use may be poor due to slipperiness during application or strong film feeling after application.

<Carboxyvinyl polymer>
A carboxyvinyl polymer that can be used in the present invention refers to a water-soluble polymer having a carboxyl group. It consists mainly of a polymer of acrylic acid. Carboxyvinyl polymer is a white acidic powder, and is an acidic compound having a pH of about 3 in a 1% by mass aqueous solution.
Carboxyvinyl polymers can be used to prepare various gel-like compositions with different viscosities by neutralizing the pH with a basic compound. Basic compounds used for neutralization include triethanolamine, monoethanolamine, diisopropanolamine, triethylamine, hydroxide compounds such as sodium hydroxide and potassium hydroxide, and arginine.
The amount of the basic compound used for neutralization is not particularly limited. The viscosity of the gel composition or cosmetic may be appropriately adjusted so as to be within a suitable range. As the carboxyvinyl polymer used in the present invention, commercially available products commonly used as thickeners in the field of cosmetics can be used. Examples include NTC-CARBOMER 380/381 (Nikko Chemicals), Hibis Wako 103/104/105 (Fuji Film Wako Pure Chemical Industries) and Carbopol 980/981 (Lubrizol Japan).

<Alkyl acrylic acid/methacrylate copolymer>
The alkyl acrylate/methacrylate copolymer used in the present invention refers to a copolymer of acrylic acid and alkyl methacrylate (C10 to C30).
Alkyl acrylic acid/methacrylate copolymer can be neutralized with a basic compound in the same manner as carboxyvinyl polymer to prepare various gel-like compositions having different viscosities. Basic compounds used for neutralization include triethanolamine, monoethanolamine, diisopropanolamine, triethylamine, hydroxide compounds such as sodium hydroxide and potassium hydroxide, and arginine.
The amount of the basic compound to be blended is not particularly limited, and may be appropriately adjusted so that the viscosity of the gel composition or cosmetic is within a suitable range.
As the alkyl acrylate/methacrylate copolymer used in the present invention, a commercially available product that is widely used as a thickening agent in the field of cosmetics may be used. Commercially available products include PEMULEN TR-1/TR-2, CarboPol Ultrez 20/21 (Nippon Lubrizol), and AQUPEC HV-701EDR/HV-801ERK/HV-803ERK (Sumitomo Seika).

(B) Polyoxyethylene glyceryl ether Polyoxyethylene glyceryl ether used in the present invention refers to polyethylene glycol ether of glycerin. In the polyoxyethylene glyceryl ether, the total number of added moles of polyoxyethylene groups is preferably 7-31, more preferably 12-26. Such polyoxyethylene glyceryl ethers are widely used as moisturizing agents in the field of cosmetics, and commercially available products can be used. Commercially available products include Brownon GL-20, Brownon GL-26 (Aoki Yushi Kogyo), Uniox G-1200 (NOF), and Union RG-120 (Shin Nippon Rika).
In the present invention, the blending amount of polyoxyethylene glyceryl ether is preferably 0.5 to 10% by mass, more preferably 1.5 to 6.5% by mass.

(C) Cholesteric Liquid Crystal In the present invention, any cholesteric liquid crystal compound for cosmetics can be used as the cholesteric liquid crystal from the viewpoint of skin safety. It can be appropriately selected and used according to the color development and coloring of the cosmetic.
Specific examples of cholesteric liquid crystals that can be used in the present invention include cholesteryl formate, cholesteryl acetate, cholesteryl propionate, cholesteryl butyrate, cholesteryl pentanate, cholesteryl hexanate, cholesteryl heptanate, cholesteryl octanate, and cholesteryl. Nonanoate, Cholesteryl Decanoate, Cholesteryl Dodecanoate (Cholesteryl Laurate), Cholesteryl Myristate, Cholesteryl Palmitate, Cholesteryl Stearate, Cholesteryl Oleate, Cholesteryl Oleyl Carbonate, Cholesteryl Linoleate, Cholesteryl 12-Hydroxystearate, Cholesteryl Mercaptan, Cholesteryl chloride, cholesteryl fluoride, cholesteryl bromide, cholesteryl iodide and the like can be mentioned.
Cholesteric liquid crystals that are generally preferred as cosmetics include a mixture of alkyl cholesterol (eg, cholesteryl nonanoate), cholesteryl halide (eg, cholesterol chloride), and cholesteryl oleyl carbonate. Liquid crystals other than these can also be used by appropriately mixing them. It may also be one commercially available as a mixture for cosmetics. Any composition can be used as long as it develops color as a liquid crystal in the temperature range (5° C. to 50° C.) in which the cosmetic is used. As such a commercial product, Ecolano CLC-678 (Nippon Fine Chemical Co., Ltd.) can be exemplified. The viscosity of Ecolano CLC-678 (Nippon Fine Chemical Co., Ltd.) (cholesteric liquid crystal) is 4000 to 7000 mPa·s when measured with a Brookfield viscometer (25° C., No. 4 rotor, 12 rpm, 30 seconds).
The amount of the cholesteric liquid crystal compounded is preferably 0.1 to 5% by mass, preferably 0.5 to 3% by mass, particularly preferably 0.7 to 1.5% by mass, based on the total amount of the gel cosmetic.

The viscosity of the gel cosmetic of the present invention is 5,000 to 60,000 mPa·s, preferably 5,000 to 30,000 mPa·s when measured with a Brookfield viscometer (25° C., No. 4 rotor, 12 rpm, 30 seconds). It is preferable that the content is in this range, since the gel-like cosmetic has good usability.

Other Optional Ingredients In the gel-like cosmetic of the present invention, ingredients that are commonly used in cosmetics, external skin preparations, etc. can be appropriately blended within a range that does not impair the effects of the present invention. Such optional ingredients include oils, polyhydric alcohols, water-soluble polymers, pigments and other powders, ultraviolet absorbers, lower alcohols, and other active ingredients as shown below.

<Oil solution>
The oil agent can be blended within the range of maintaining color development without destroying the structure of the cholesteric liquid crystal. Examples thereof include fatty acids, higher alcohols, hydrocarbons, fats/waxes, synthetic ester oils, and silicone oils. Examples of fatty acids include oleic acid, isostearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid and undecylenic acid. Examples of higher alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, isostearyl alcohol, and batyl alcohol. Hydrocarbons include squalane, liquid paraffin, ceresin, vaseline, microcrystalline wax and the like. Fats and waxes include macadamia nut oil, avocado oil, corn oil, olive oil, rapeseed oil, sesame oil, castor oil, safflower oil, cottonseed oil, jojoba oil, coconut oil, palm oil, liquid lanolin, hydrogenated coconut oil, hydrogenated oil , Japanese wax, hydrogenated castor oil, beeswax, candelilla wax, carnauba wax, ivory wax, lanolin, reduced lanolin, hard lanolin, and jojoba wax. Synthetic ester oils include cetyl ethylhexanoate, ethylhexyl palmitate, isononyl isononanoate, isotridecyl isononanoate, isopropyl myristate, hexyldecyl isostearate, isostearyl isostearate, diisopropyl adipate, di-2-ethylhexyl sebacate, lactic acid. Cetyl, diisostearyl malate, glyceryl tri-2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, trimethylolpropane triisostearate, pentaerythritol tetra-2-ethylhexanoate, isostearyl pivalate , isodecyl pivalate, phytosteryl macadamia nut fatty acid, di(phytosteryl/octyldodecyl) lauroyl glutamate, di(octyldodecyl/phytosteryl/behenyl) lauroyl glutamate, and the like. Examples of silicone oils include linear polysiloxanes such as dimethylpolysiloxane, methylphenylpolysiloxane and diphenylpolysiloxane; cyclic polysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexanesiloxane; and amino-modified polysiloxanes. , polyether-modified polysiloxane, alkyl-modified polysiloxane, and fluorine-modified polysiloxane. In the present invention, the blending amount that maintains color development without destroying the structure of the cholesteric liquid crystal is preferably less than 1% by mass, more preferably 0.5% by mass or less, and particularly preferably 0%, based on the total amount of the cosmetic. 0.1% by mass or less is preferable. In the present invention, if an oil agent is blended, the gel composition may become turbid and may not be transparent or translucent.

<Water-soluble polymer>
In the present invention, carboxyvinyl polymer and/or alkyl acrylate/methacrylate copolymer are essential components as component (A). A necessary water-soluble polymer can be blended as long as the effects of the present invention are not impaired. Specifically, polysaccharides such as starch, starch derivatives, cellulose, cellulose derivatives, pectin, agarose, xanthan gum, gellan gum, locust bean gum, carrageenan, sodium alginate, white fungus polysaccharide, sorbitol fermented polysaccharide, sodium acrylate, (acrylic Synthetic polymers such as ammonium acid dimethyltaurate/vinylpyrrolidone) copolymer, (acryloyldimethyltaurate ammonium/beheneth-25 methacrylate) crosspolymer, and (acrylates/beheneth-25 methacrylate) copolymer.

<Polyhydric alcohol>
The gel-like cosmetic of the present invention may optionally contain 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,3-butylene glycol, 1,2-pentanediol, Polyhydric alcohols such as 1,2-hexanediol, 2,4-hexanediol, ethylhexylglycerin, batyl alcohol and 1,2-octanediol polyethylene glycol, glycerin, sorbitol, mannitol, xylitol and erythritol may be added.

<Powder>
The gel-like cosmetic of the present invention may contain powders that are dispersed in the gel-like composition. Examples of such powders include powders such as mica, talc, kaolin, synthetic mica, calcium carbonate, magnesium carbonate, anhydrous silicic acid (silica), aluminum oxide and barium sulfate.

<Other active ingredients>
Preservatives such as ethanol, pH adjusters such as potassium hydroxide, sodium hydroxide, citric acid and hydrochloric acid, sequestering agents such as edetic acid and etidronic acid, moisturizing ingredients such as sodium pyrrolidonecarboxylate, lactic acid and sodium lactate. , vitamin A or its derivatives, vitamin B6 hydrochloride, vitamin B6 tripalmitate, vitamin B6 dioctanoate, vitamin B2 or its derivatives, vitamin B12, vitamin B15 or its derivatives such as B vitamins, vitamin C or its derivatives, α- Tocopherol, β-tocopherol, γ-tocopherol, vitamin E such as vitamin E acetate, vitamin D, vitamin H, pantothenic acid, pantethine, pyrroloquinoline quinone and other vitamins, sphingolipids, phospholipids, dipotassium glycyrrhizinate, Cosmetically useful ingredients such as stearyl glycyrrhetinate can be incorporated.

<Preparation of gel cosmetics>
To prepare the gel-like cosmetic of the present invention, it is preferable to follow the steps below.
(Step 1) First, components (A), (B) and other optional components are mixed by a conventional method to form a gel composition having a viscosity of 1000 to 3000 mPa·s. Next, the cholesteric liquid crystal of component (C) is added to and dispersed in this low-viscosity gel composition.
(Step 2) After that, a basic compound such as sodium hydroxide is added to neutralize component A so that the viscosity of the gel-like cosmetic becomes 5000 to 60000 mPa·s.
By preparing the cholesteric liquid crystal in two steps, it is possible to disperse the cholesteric liquid crystal in the gel composition so as to exhibit a beautiful appearance, and to obtain a gel cosmetic having a desired viscosity. The pH of the gel cosmetic of the present invention is 5-7. In order to obtain a gel composition having a viscosity of 1000 to 3000 mPa s in step 1, part of the basic compound used for neutralization in step 2 is added in step 1 to partially neutralize component A, The viscosity of the gel composition may be adjusted, or the amount of water in step 1 may be adjusted in advance so that the viscosity of the gel composition in step 1 is in the range of 1000 to 3000 mPa·s. In the former case, the addition of the basic compound is a preparative method performed in both step 1 and step 2. In the latter case, the addition of the basic compound is a preparation method performed only in step 2.

EXAMPLES Gel-like cosmetics of Examples and Comparative Examples are prepared below, and evaluation tests using them are shown to explain the present invention in detail.
1. Preparation of Gel Cosmetics Gel cosmetics of Examples 1 to 6 having the composition shown in Table 1 and Comparative Examples 1 to 11 having the composition shown in Table 2 were prepared. All test sample preparations were performed on a 300 g scale using 500 mL beakers.
The manufacturers and product names of the ingredients marked with * in the table are as follows.
*1 Hivis Wako 103 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
*2 AQUPEC HV-701EDR manufactured by Sumitomo Seika Co., Ltd.
*3 PEMULEN TR-1 manufactured by Lubrizol
*4 Union RG-120 manufactured by Shin Nippon Rika Co., Ltd.
*5 Brownon GL-20 manufactured by Aoki Oil Co., Ltd.
*6 Brownon GL-26 manufactured by Aoki Oil Co., Ltd.
*7 Uniol SGP-65 manufactured by NOF Corporation
*8 SY-DP9 manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.
*9 Uniol TG-1000 manufactured by NOF Corporation
*10 Unilube 50TG-32 manufactured by NOF Corporation
*11 Will Bright S-753D manufactured by NOF Corporation
*12 Nippon Fine Chemical Co., Ltd. Ecolano CLC-678 (former YOFCO CLC-678): dihydrocholesteryl oleate, cholesteryl nonanoate, dihydrocholesteryl butyrate, cholesteryl butyrate, phytosteryl oleate

(1) Components (A) and (B), components corresponding to components (A) and (B), and other optional components are dissolved in a required amount of purified water to prepare an aqueous phase solution.
(2) Partially neutralize the component (A) contained in the aqueous phase using a potassium hydroxide solution, and adjust the aqueous phase viscosity to 1000 to 3000 mPa s (Brookfield viscometer 25 ° C., rotor No. 3, Rotation speed 12 rpm, measurement time 30 seconds) to adjust the viscosity.
(3) Component (C) is added and pre-dispersed at room temperature at 200 rpm for 30 seconds using Three One Motor (manufactured by Shinto Kagaku Co., Ltd.) and paddle blades.
(4) All of the potassium hydroxide solution is added to neutralize the component (A).
(5) Stirring is performed at 100 rpm for 60 seconds using a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) and paddle blades.
(6) The prepared gel-like cosmetic is used as an evaluation sample.

2. Evaluation of gel cosmetics (1) Evaluation of physical properties (viscosity)
The viscosity was measured using a Brookfield viscometer (25° C., rotor No. 3 or rotor No. 4, number of revolutions 12 rpm, measurement time 30 seconds).
(pH)
The pH was measured using a pH meter (Horiba, Ltd.; pH/ION METER F-32).

(2) Appearance Evaluation A glass bottle (screw tube No. 7: diameter 3.5 cm) was filled with a sample, and a specialized sensory evaluator evaluated the dispersion of the cholesteric liquid crystal and the appearance of the structural color according to the following criteria.
(Evaluation criteria)
○: Dispersion and color development of cholesteric liquid crystals can be clearly recognized △: Dispersion and color development of cholesteric liquid crystals are somewhat unclear, and structural colors cannot be recognized very clearly ×: Dispersion and color development of cholesteric liquid crystals are unclear, structure The color is hardly recognizable. Regarding the transparency of the gel composition (gel base), the 18-point type can be clearly read when visually observed from the side of the glass bottle, and all of Examples 1 to 6 are transparent. rice field.

(3) Evaluation of feeling in use A sample was taken on the back of the hand, and the feeling in use (non-stickiness during application, non-stickiness after application, moisturizing feeling after application) was evaluated by a sensory evaluator.
(Evaluation item)
1) Absence of stickiness at the time of application: Absence of stickiness from when the sample blends into the skin to immediately after being blended in 2) Absence of stickiness after application: Absence of stickiness after the sample has blended into the skin 3) After application Moisturizing feeling: Good moist feel immediately after applying the sample to the skin and letting it absorb (evaluation criteria)
○: Good △: Somewhat good ×: Bad

(4) Measurement of Cholesteric Liquid Crystal Dispersed Particle Diameter and Number of Pieces A glass dish having a thickness of 2 mm was filled with each of the cosmetic compositions described in Examples and Comparative Examples until it was completely leveled, and this was used as a test sample. The particle size and number of cholesteric liquid crystals dispersed in the gel base (gel composition) were measured. Measurement was performed using a digital microscope VHX-5000 manufactured by KEYENCE. Observation images were also taken.
Observation was performed at a magnification of 30 times.
The dispersion state of the cholesteric liquid crystal was confirmed by measuring the maximum diameter, the minimum diameter, and the number of liquid crystal particles according to the following criteria.
(standard)
Maximum diameter: Arithmetic mean of the length of the maximum distance between any two points on the inner circumference of the liquid crystal particle Minimum diameter: Arithmetic of the minimum value of the distance between two parallel straight lines when the liquid crystal particle is sandwiched between two straight lines Average number of liquid crystals: Number of liquid crystals per unit area

3. Evaluation Results Evaluation results are shown in the lower part of Tables 1 and 2.

Each of the gel-like cosmetics of Examples 1 to 6 having the configuration (A+B+C) of the present invention has a beautiful appearance in which the unique beautiful structural color of the cholesteric liquid crystal can be seen in the transparent gel-like composition. In addition, the feeling of use (no stickiness at the time of application, no stickiness after application, moisturizing feeling after application) was excellent.
Comparative Examples 1 to 11 all have compositions lacking the B component (A+C). In Comparative Example 1, the B component was replaced with water, in Comparative Example 2 with an optional polyhydric alcohol, and in Comparative Examples 3 to 11 with components similar to the B component.
The gel-like cosmetics of Comparative Examples 1 and 2 were found to be sticky at the time of blending in the evaluation of feeling during use (evaluation of Δ and evaluation of ×). And it was evaluated that stickiness was generated after application (both evaluations were x).
Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6, Comparative Example 7, Comparative Example 10, and Comparative Example 11 contain a polyoxypropylene group or a polyoxybutylene group instead of the B component. Cosmetics containing polyoxyalkylene alkyl ethers. In the gel cosmetic of this composition, cholesteric liquid crystals were finely dispersed. In addition, the cholesteric liquid crystals were too finely dispersed, so that the appearance appeared cloudy, and the transparency of the gel composition (base) was impaired. In addition, finely dispersed cholesteric liquid crystals are inhibited from developing unique colors (structural colors) as cholesteric liquid crystals, and the aesthetics of gel cosmetics are impaired.
The gel-like cosmetics of Comparative Examples 8 and 9 have compositions containing polyethylene glycol. The gel composition of this composition gave a strong sticky feeling when applied to the skin (evaluation ×). Furthermore, after application, a squeaky feeling was generated, and a good moist touch was not obtained, and the evaluation was x. The compositions of Comparative Examples 8 and 9 had a beautiful appearance, but were sticky and did not provide the moisturizing feeling peculiar to cosmetics containing cholesteric liquid crystals.
Next, the results of observing the appearance of the gel cosmetics will be described in detail.

1 to 4 show images obtained by observing the size of the liquid crystal, which affects the appearance and beauty of the gel cosmetic.
FIG. 1 is an image obtained by observing cholesteric liquid crystals in the gel cosmetic of Example 4. FIG. The cholesteric liquid crystal particles dispersed in the gel-like base (gel-like composition) had a maximum diameter of 138 μm (arithmetic mean), and 463 particles were dispersed per 1 cm ² , giving off a very beautiful structural color (gloss). Appearance evaluation was "0".
FIG. 2 is an image obtained by observing cholesteric liquid crystals of the gel cosmetic of Example 2. FIG. Cholesteric liquid crystal particles had a maximum diameter of 253 μm (arithmetic mean), and 70 relatively large particles were dispersed per 1 cm ² , giving off a very beautiful structural color (gloss). Appearance evaluation was "0".
In all of the gel-like cosmetics of Examples 1 to 6, including Examples 2 and 4, the structural color of the cholesteric liquid crystal can be visually confirmed, and the particles can be clearly identified in the transparent gel-like base. The appearance was extremely beautiful.

An observation image of Comparative Example 5 is shown in FIG. The cholesteric liquid crystal particles dispersed in the gel-like base had a maximum diameter of 76 μm (arithmetic mean), a minimum diameter of 49 µm (arithmetic mean), and the number of particles was 2392/cm ² . That is, the maximum and minimum diameters of the cholesteric liquid crystal particles were small, less than 100 μm, and the structural color peculiar to the cholesteric liquid crystal was hardly visible due to the large number of liquid crystal particles dispersed therein. Appearance evaluation was "x". The same could be said for Comparative Examples 6, 7 and 10.
Further, Comparative Example 11 is rated as "Δ" in appearance. An observed image is shown in FIG. The cholesteric liquid crystal particles of Comparative Example 11 had a maximum diameter of 87 μm (arithmetic average), a minimum diameter of 67 μm (arithmetic average), and a particle number of 866/cm ² . Although the maximum and minimum diameters of the cholesteric liquid crystal particles are larger than those of Comparative Example 5, they are smaller than those of Examples, being less than 100 μm. Since a large number of liquid crystal particles are dispersed, the structural color peculiar to cholesteric liquid crystals cannot be clearly recognized. However, it was evaluated as not very beautiful as a gel-like cosmetic (△ evaluation).
From the analysis of such observation images, in order to make the appearance of gel-like cosmetics containing cholesteric liquid crystals beautiful, it is necessary to (1) increase the particle size of the cholesteric liquid crystals, and (2) increase the amount of liquid crystals dispersed per unit volume. It was considered important to keep the number of particles within an appropriate range. In this test, (1) the arithmetic average value of the maximum diameter of the cholesteric liquid crystal is 120 to 253 μm, and (2) the number of liquid crystal particles observed when the thickness of the sample is 2 mm is 70 to 712/cm ² . At times, I was able to confirm that I felt beautiful.
From this, the arithmetic average value of the maximum diameter obtained by image analysis of the cholesteric liquid crystal particles dispersed in the gel-like base should not be less than 100 μm, and the number of liquid crystal particles observed when the thickness of the sample is 2 mm. does not exceed 800/cm ² is important for obtaining a beautiful appearance.
In summary, image analysis with a microscope at a sample thickness of 2 mm and a magnification of 30 times revealed that (1) the arithmetic mean of the maximum diameter of the cholesteric liquid crystal was 100 to 300 μm, and (2) the number of cholesteric liquid crystal particles was 50 to 800. /cm ² , Criterion A was established, which means that the appearance of the gel-like cosmetic containing cholesteric liquid crystal is felt to be beautiful.

In addition, in the above-mentioned criterion A, since the image analysis by microscopic observation is used as it is, particles too small to be visually recognized are also analyzed. Therefore, there is a possibility that the value will be smaller than the size of the particles by visual observation. Therefore, as a method for approximating the size of the liquid crystal particles observed by visual observation, image analysis was performed based on the same criteria except that the liquid crystal particles less than 100 μm in size were excluded from the microscopic observation image. The arithmetic mean of the maximum diameter of the cholesteric liquid crystal, the measured number of particles of the cholesteric liquid crystal, and the derived criterion B were as follows.
[Analysis that excludes liquid crystal particles of less than 100 μm from the image observed with a microscope]
When the maximum diameter of the cholesteric liquid crystal particles was measured after excluding the liquid crystal particles of less than 100 μm from the image observed with a microscope, the arithmetic average value of the maximum diameters was 515 μm for Example 2 and 268 μm for Example 4. The maximum value of the maximum diameter of each sample was 2020 μm for Example 2 and 1173 μm for Example 4. The ratio of the number of particles of 100 μm or more to the liquid crystal particles in the sample observed with a microscope before removing the liquid crystal particles of less than 100 μm (number of liquid crystal particles of 100 μm or more/total number of liquid crystal particles) was 0.60 in Example 2. Example 4 was 0.45, Comparative Example 5 was 0.27, and Comparative Example 11 was 0.35. Based on the results in Tables 1 and 2, the number of liquid crystal particles observed with a microscope (30x magnification) when the thickness of the sample is 2 mm is 50 to 800/cm ² , and more than 40% of them. It has been found that when is particles having a maximum diameter of 100 μm or more, the appearance of the gel-like cosmetic containing cholesteric liquid crystals is felt to be beautiful.
(Standard B)
(1) Arithmetic average value of the maximum diameter of cholesteric liquid crystals: 200 to 2500 μm, (2) Cholesteric liquid crystals when excluding liquid crystal particles of less than 100 μm in the image observed by a microscope with a sample thickness of 2 mm and a magnification of 30 times. When the number of particles is 23 to 480/cm ² , the appearance of the gel-like cosmetic containing cholesteric liquid crystals is felt to be beautiful.

The manufacturing process for dispersing the cholesteric liquid crystal composition in the gel composition (gel base) is as described above, and the results of examining various processes are described below.

A cholesteric liquid crystal composition (component C) is dispersed in a gel composition (gel base: A + B) so that the structural color of the cholesteric liquid crystal particles can be seen visually, resulting in a gel with a beautiful appearance. In order to obtain a cosmetic, the viscosity of the component C and the viscosity of the gel composition are not greatly different, and the viscosity of the gel composition is adjusted so that the viscosity of the gel composition is slightly low, and the cholesteric liquid crystal of the component C is added. Dispersion is preferable because it can be produced without complicated adjustment.
That is, it is preferable to take the following steps.
(1) At least one water solution selected from (A) a carboxyvinyl polymer and an alkyl acrylic acid/methacrylate copolymer whose viscosity is adjusted to be 1000 to 3000 mPa s when measured with a Brookfield viscometer a step of dispersing cholesteric liquid crystals in a transparent or translucent gel composition containing a polyoxyethylene glyceryl ether and (B) a polyoxyethylene glyceryl ether;
(2) Next, a step of neutralizing the composition obtained in step (1) with a basic compound and increasing the viscosity to 5000 to 60000 mPa·s when measured with a Brookfield viscometer.
On the other hand, when the viscosity of the gel-like composition was equal to or higher than the viscosity of the cholesteric liquid crystal, or when it was as low as 1/3 or less of the viscosity of the cholesteric liquid crystal, the following results were obtained.
(When the viscosity of the gel-like composition is the same or higher)
When a cholesteric liquid crystal with a viscosity of 5000 mPa·s was dispersed in a gel-like base with a high viscosity (5000 mP·s or more), the stirring time was increased in order to obtain a uniform dispersion. Due to this long stirring time, the dispersed cholesteric liquid crystals become finer, making it difficult to visually recognize the characteristic structural color, making it difficult to obtain a gel-like cosmetic with a beautiful appearance.
(When the viscosity of the gel composition is low)
On the other hand, when trying to disperse a cholesteric liquid crystal with a viscosity of 5000 mPa s in a solution with a low viscosity (less than 1000 mPa s), due to the difference in specific gravity between the base and the cholesteric liquid crystal, it is possible to floated on the liquid surface and could not be sufficiently dispersed, making it difficult to obtain a homogeneous gel-like cosmetic.
For these reasons, the carboxyvinyl polymer and/or alkyl acrylate/methacrylate copolymer is partially neutralized once with a basic substance, or by adjusting the amount of water, gel can be obtained. A step of dispersing the cholesteric liquid crystal (4000 to 7000 mP s) after adjusting the composition to an appropriate viscosity (1000 to 3000 mP s) (step 1), further neutralizing by adding a basic substance, and reducing the viscosity By taking the step (Step 2) to obtain the desired gel-like cosmetic by adjustment, it is possible to obtain a gel-like cosmetic with a beautiful appearance in which particles having a beautiful structural color peculiar to cholesteric liquid crystals are uniformly dispersed. rice field.

Claims (6)

A gel-like cosmetic in which (C) is dispersed in a gel-like composition containing the following (A) and (B) .
(A) Carboxyvinyl polymer and/or acrylic acid/methacrylate alkyl copolymer (B) Polyoxyethylene glyceryl ether in an amount of 1.5 to 6.5% by mass based on the total amount of the cosmetic
(C) 0.5 to 3% by mass of cholesteric liquid crystal relative to the total amount of the cosmetic (C) A transparent or/translucent gel-like composition in which the cholesteric liquid crystal contains (A) a carboxyvinyl polymer and/or an acrylic acid/methacrylate alkyl copolymer and (B) a polyoxyethylene glyceryl ether as constituent components. The gel-like cosmetic according to claim 1, which is dispersed in 3. The cosmetic gel according to claim 1, wherein (C) the cholesteric liquid crystal is a mixture containing at least dihydrocholesteryl oleate, cholesteryl nonanoate, dihydrocholesteryl butyrate, cholesteryl butyrate, and phytosteryl oleate. 4. The cosmetic gel according to any one of claims 1 to 3, wherein the total number of added moles of polyoxyethylene groups in (B) polyoxyethylene glyceryl ether is 7 to 31. The gel-like cosmetic according to any one of claims 1 to 4, which has a viscosity of 5,000 to 60,000 mPa·s when measured with a Brookfield viscometer. A method for producing a cholesteric liquid crystal-containing gel-like cosmetic according to any one of claims 1 to 5, comprising the following steps.
(1) At least one water solution selected from (A) a carboxyvinyl polymer and an alkyl acrylic acid/methacrylate copolymer whose viscosity is adjusted to be 1000 to 3000 mPa s when measured with a Brookfield viscometer a step of dispersing cholesteric liquid crystals in a transparent or/translucent gel-like composition containing a polyoxyethylene glyceryl ether and (B) polyoxyethylene glyceryl ether as constituent components.
(2) Next, a step of neutralizing the composition obtained in step (1) with a basic compound and increasing the viscosity to 5000 to 60000 mPa·s when measured with a Brookfield viscometer.

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