JP2001122741A - Cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cosmetic capable of imparting a new kind of color effect, differentiating color tone by viewing angle and changing the color tone by light or heat after applying to hair, etc. SOLUTION: This cosmetic comprises a cholesteric liquid crystalline compound whose selective reflection wavelength changes by light or temperature in the cosmetic comprising the cholesteric liquid crystalline compound selectively reflecting light having arbitrary wavelength in visible area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cosmetic which can exhibit a vivid color due to reflection of light and whose color changes with light or temperature, in particular, a hair cosmetic.

[0002]

2. Description of the Related Art Conventionally, hair cosmetics for gray hair coloring, which are classified as permanent hair coloring agents, have been the mainstream. However, in recent years, under various demands for hair cosmetics, a hair manicure and a color rinse that can be used more easily even for gray hair dyeing, and a hair color and a hair manicure that can dye black hair to a desired color. Etc. have appeared.
In addition, new styles of dressing, mainly young people, have been applied to not only hair but also nails and skin to give various decorations. Permanent hair dyes are made by oxidizing and polymerizing by forming an amine or phenolic oxidation dye into the inside of the hair and simultaneously oxidizing (hydrogen peroxide) to form a high-molecular dye. To deposit. Since the high-molecular pigment formed in the hair cannot escape from the inside of the hair, the long-lasting effect of the hair dyeing is high. However, these oxidative hair dyes are irritating to the skin, eyes, and scalp, and also break the chemical bonds of cystine that constitutes the hair, thereby weakening the hair, and are likely to cause hair damage. There was a problem.

[0003] Further, the above-mentioned hair color and hair manicure are called temporary hair dyes, which dye the hair by physically attaching pigments or dyes to the surface of the hair, and thus may damage the hair or dye the skin. There is also an advantage that the hair can be easily returned to the original color because it can be easily washed off with shampoo. Therefore, although the hair dyeing effect is not persistent, it does not have a problem as in the above-mentioned permanent hair dye. As such a hair color and hair manicure, those containing a pearl luster pigment therein to impart pearl luster to hair are known.

[0004] For example, Japanese Patent Application Laid-Open No. 62-255414 discloses a carboxyvinyl polymer as a thickening agent having a high effect of preventing sedimentation of titanium mica, using titanium mica as a pearl luster pigment, and titanium mica on hair. Using an anionic resin as a binder for immobilizing is proposed. Also, Japanese Patent Application Laid-Open No. 11-171729
In the official gazette, when using titanium mica and using titanium mica having a relatively small particle diameter, in which the proportion of particles having a relatively large particle diameter in the total amount of titanium mica used is small, a glittering feeling is felt. Hair cosmetics that can change the color tone of hair with a natural feeling without giving it have been proposed. However, titanium mica as a pigment for imparting a pearl luster requires an extremely thin titanium oxide thin film to be accurately provided on mica flakes in order to develop color due to its interference effect. Further, in a hair cosmetic using titanium mica, when the composition of the titanium mica pigment, for example, the thickness of titanium oxide is determined, its pearl luster is also uniquely determined, and the color does not change thereafter. JP-A-7-304983 describes the application of a pigment having a liquid crystal structure having a chiral phase to the field of cosmetics, but does not mention the light or temperature dependence of the color of the pigment.

[0005]

The present invention can provide a new kind of color effect by containing an organic compound that selectively reflects light having an arbitrary wavelength in the visible region.
It is an object of the present invention to provide a cosmetic that varies in color tone depending on the viewing angle and changes its color tone by light or heat after being applied to hair or the like.

[0006]

The above object is achieved by providing the following cosmetics. (1) A cosmetic containing a cholesteric liquid crystal compound that selectively reflects light having an arbitrary wavelength in the visible region, comprising a cholesteric liquid crystal compound whose selective reflection wavelength of the cholesteric liquid crystal compound changes with light. . (2) A cosmetic comprising a cholesteric liquid crystal compound which selectively reflects light having an arbitrary wavelength in the visible region, wherein the cosmetic comprises a cholesteric liquid crystal compound whose selective reflection wavelength of the cholesteric liquid crystal compound changes with temperature. . (3) The cosmetic according to (1) or (2), wherein the cosmetic is a hair cosmetic.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The cosmetic of the present invention is characterized in that it contains a cholesteric liquid crystal compound that selectively reflects light having an arbitrary wavelength in the visible region. Since the cosmetic of the present invention contains an organic compound that selectively reflects light having an arbitrary wavelength in the visible region, which is different from a normal colored pigment that absorbs part of incident light and reflects the rest, the color effect Is based on light interference.
And, as described below, it provides a new kind of color effect different from the color effect of cosmetics containing titanium mica, which is conventionally known as a color effect based on light interference. Cosmetics can be provided.

A cholesteric liquid crystal is a liquid crystal having a periodic helical structure. In addition to a cholesterol-based liquid crystal compound, a chiral compound (optically active compound) is added to a rod-like liquid crystal compound (composition) exhibiting a nematic phase such as cyanobiphenyl. A cholesteric liquid crystal phase (chiral nematic phase) can be easily obtained by adding a chiral carbon atom to the molecular structure of the nematic liquid crystal. The cholesteric liquid crystal has a structure in which the arrangement of molecules is slightly twisted along the helical axis, and the incident light having a wavelength corresponding to the product of the helical pitch and the average refractive index of the liquid crystal is selectively reflected. Color develops.
When the helical pitch of the cholesteric liquid crystal molecular arrangement is counterclockwise, the right circularly polarized light component of the incident light is transmitted, and the left circularly polarized light component is selectively reflected. As the cholesteric liquid crystal compound whose selective reflection wavelength changes according to light or temperature, a compound having a helical pitch substantially corresponding to the wavelength of light in the visible region is preferably used, and examples thereof include the following.

[0009]

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[0010]

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[0011]

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[0012]

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[0013]

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The method for producing these compounds is described, for example, in JP-A-59-83112, F. Vicentini et al.
l., Liquid Crystals, 24 (4), 483-488 (1998), and
AUBobrovsky, Liquid Crystals, 25 (6), 679-687 (199
8) etc.

The cholesteric liquid crystal compound in the present invention is desirably added to cosmetics in the form of solid fine powder, capsules or the like in which the helical molecular arrangement is fixed. The solid fine powder in which the molecular arrangement in the helical state is fixed can be obtained by forming a polymerizable liquid crystal or a polymer liquid crystal into a film, cross-linking as necessary, and pulverizing the film. The liquid crystal molecules are aligned by an alignment film, an electric field, a magnetic field, or the like. Such a method is known, for example, from the following document: : CA113 (22), 201523y; CA113 (14), 124523u; CA112
(18), 169216s; CA112 (16), 149138q; CA112 (4), 21552c;
CA111 (16), 144258y; CA111 (4), 24780r. For example, metal,
The liquid crystal compound can be aligned by knife coating on a plastic or glass substrate. This base material may be provided with an alignment film made of polyamide or polyvinyl alcohol as the case may be. Alternatively, the liquid crystal molecules can be aligned by shearing between two polyethylene terephthalate sheets. For details of these methods, see JP-A-7-304.
983, EP-A-358208 and the like. Furthermore, a more complicated color effect can be obtained by mixing, as the liquid crystal fine powder, liquid crystal fine powders having different helical pitches and different center wavelengths of selective reflection. The shape of the fine powder of the cholesteric liquid crystal is preferably plate-like, and the thickness of the plate is 1 to 20.
μm, preferably 3-10 μm, is suitable. The size of the fine powder is 1 to 1000 μm, preferably 1 to 100 μm, as an average particle size.

The method of encapsulating the cholesteric liquid crystal compound in microcapsules can be performed by using a known microencapsulation method. As the microcapsule forming method, an interfacial polymerization method and an internal polymerization method are suitable. For details of the capsule forming method and specific examples of the reactants, see US Pat. No. 3,726,804,
No. 3,796,669 and the like. For example, when polyurea or polyurethane is used as the capsule wall material, a polyisocyanate and a second substance (for example, polyol,
Polyamine) is mixed in an aqueous medium or an oil medium to be encapsulated, emulsified and dispersed in water and then heated to cause a polymer forming reaction at the oil droplet interface to form microcapsule walls. Note that polyurea is also generated when the addition of the second substance is omitted.

Hereinafter, a method for producing microcapsules will be described. First, a compound contained in a microcapsule is dissolved or dispersed in a hydrophobic organic solvent serving as a core of the capsule. In this case, the organic solvent has a boiling point of 100
Organic solvents at −300 ° C. are preferred. In the core solvent, polyvalent isocyanate is further added as a wall material (oil phase). On the other hand, as the aqueous phase, an aqueous solution in which a water-soluble polymer such as polyvinyl alcohol or gelatin is prepared,
Next, the oil phase is charged and emulsified and dispersed by means such as a homogenizer. At this time, the water-soluble polymer acts as a stabilizer for emulsification and dispersion. A surfactant may be added to at least one of the oil phase and the aqueous phase in order to perform the emulsification and dispersion more stably.

The amount of the polyvalent isocyanate used is determined so that the microcapsules have an average particle size of 0.3 to 12 μm and a wall thickness of 0.01 to 0.3 μm. The dispersed particle diameter is generally about 0.2 to 10 μm. In the emulsified dispersion, a polymerization reaction of the polyvalent isocyanate occurs at the interface between the oil phase and the aqueous phase to form a polyurea wall.

If a polyol is added to the aqueous phase, the polyvalent isocyanate can react with the polyol to form a polyurethane wall. It is preferable to keep the reaction temperature high or to add an appropriate polymerization catalyst in order to increase the reaction rate. Details of polyvalent isocyanates, polyols, reaction catalysts, and polyamines for forming a part of the wall material are described in detail in books (Polyurethane Handbook, edited by Keiji Iwata, Nikkan Kogyo Shimbun (198)
7)).

As the polyvalent isocyanate compound used as a raw material for the microcapsule wall, a compound having a trifunctional or more isocyanate group is preferable, but a bifunctional isocyanate compound may be used in combination. Specifically, diisocyanates such as xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product, and isophorone diisocyanate are used as main raw materials, and dimers or trimers thereof (buret or isocyanurate) are used. ) In addition, adducts of polyols such as trimethylolpropane and bifunctional isocyanates such as xylylene diisocyanate, which are polyfunctional, and adducts of polyols such as trimethylolpropane and bifunctional isocyanates such as xylylene diisocyanate Examples include compounds into which a high molecular weight compound such as polyether having active hydrogen such as polyethylene oxide is introduced, and a formalin condensate of benzene isocyanate. In addition, JP-A-62-21
Compounds described in JP-A-2190, JP-A-4-26189, JP-A-5-317694, and Japanese Patent Application No. 8-268721 are preferably used.

Since the cosmetic of the present invention contains an organic compound which selectively reflects light having an arbitrary wavelength in the visible region, particularly a cholesteric liquid crystal compound, it is a new material different from titanium mica conventionally used as a pearl pigment. Various color effects can be obtained. That is, the central wavelength of selective reflection by the cholesteric liquid crystal is obtained by multiplying the helical pitch of the liquid crystal by the average refractive index of the liquid crystal. Can be provided. In addition, since the central wavelength of the selective reflection changes depending on the incident angle, a color effect that the color tone looks different depending on the viewing angle can be obtained, and there is an advantage that the color tone is emphasized by illumination even at night. Furthermore, in the case of titanium mica pigments, the color is fixed by the material used, the thickness of titanium oxide, the manufacturing method, etc., and the color tone does not change even when the use environment changes, whereas the cholesteric liquid crystal has photochromic properties or surface roughness. Some have chromic properties, and the selective reflection wavelength can be changed by light or heat.
Therefore, it is possible to make the color tone different between indoor and outdoor, and to make the color tone different due to a temperature change (0 to 35 ° C.). Furthermore, it is impossible to immediately return to the original hair color when an unintended color is dyed with a hair color or the like, but the cosmetic of the present invention can be easily washed off with a normal shampoo. In addition, the cosmetic of the present invention hardly damages skin and hair. In addition, cholesteric liquid crystals have an advantage that they do not easily settle when dispersed in a medium because of their low specific gravity.

The cosmetic of the present invention is particularly suitable as a cosmetic for imparting a pearl-like color effect to hair, skin, nails and the like. In particular, when applied to hair, especially black hair, a vivid color effect can be obtained, so that it is effective when used as a hair cosmetic. Dosage forms suitable for hair cosmetics include gels, sprays, creams, lotions, foams, spray foams, and the like.

The cosmetic of the present invention is prepared by mixing the above-mentioned cholesteric liquid crystal compound and components necessary for the cosmetic. Further, the cosmetic of the present invention preferably contains one or both of nonionic and anionic activators in order to improve the dispersibility of the cholesteric liquid crystal compound.

Examples of the nonionic activator include polyoxyethylene alkyl ether, glycerin fatty acid ester, polyoxyethylene hydrogenated castor oil, polyoxyethylene sorbitol fatty acid ester, polyoxyethylene fatty acid ester, and coconut oil fatty acid diethanolamide. it can. Also, as the anionic activator,
Examples thereof include polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl ether sulfate, alkyl sulfate, and fatty acid salt.

The cosmetic of the present invention further comprises a cationic surfactant such as stearyltrimethylammonium chloride,
Thickening of amphoteric surfactants such as lauryl betaine, hydrocarbons such as squalane, liquid paraffin, silicones such as dimethylpolysiloxane, methylphenylpolysiloxane, amino-modified silicone, polyols such as glycerin and propylene glycol, and xanthan gum Agents, dispersion stabilizers such as clay minerals, higher alcohols, higher fatty acid esters, oils such as animal and vegetable oils, humectants, neutralizers, preservatives,
UV absorbers, antioxidants, vitamins, extracts, fragrances, and the like can be appropriately compounded as necessary.

Further, various coloring agents can be blended in the cosmetic of the present invention. Such dyes include, for example, Red No. 3, Red No. 104, Red No. 106, Red No. 20
No. 1, Red No. 202, Red No. 204, Red No. 205, Red No. 220, Red No. 226, Red No. 227, Red No. 228
No. 230, Red No. 401, Red No. 505, Yellow No. 4, Yellow No. 5, Yellow No. 202, Yellow No. 203, Yellow No. 2
04, Yellow 401, Blue 1, Blue 2, Blue 20
No. 1, Blue No. 404, Green No. 3, Green No. 201, Green No. 2
No. 04, green No. 205, orange No. 201, orange No. 203,
Tar dyes such as orange No. 204, orange No. 206 and orange No. 207; dyes commonly used in cosmetics such as natural dyes such as carminic acid, laccaic acid, pradiline and crocin;

Further, a polymer compound for stabilizing the dispersion can be added so that the fine powder of the cholesteric liquid crystal does not settle or aggregate. For example, a carboxyl group-containing vinyl polymer such as Carbopol 980 and Carbopol 981 (both manufactured by BF Goodrich) can be used. Further, an acrylic polymer which is an amphoteric polymer having a carboxyl group and a quaternary amino group in the molecule, for example, Yuka Former 202 and Yuka Former SM (all manufactured by Mitsubishi Chemical Corporation) or the like can be added. The amphoteric polymer also has the effect of fixing the fine powder of cholesteric liquid crystal to the surface of hair or skin. When the cosmetic of the present invention is used as an aerosol type, a propellant such as liquefied petroleum gas (LPG), dimethyl ether, carbon dioxide, compressed nitrogen, compressed air and the like are used.
In the case of liquefied petroleum gas or dimethyl ether, the use amount of the propellant is preferably 5 to 50% by weight based on all components of the cosmetic.

The content of the fine powder of the cholesteric liquid crystal in the cosmetic of the present invention varies depending on the type of the fine powder to be added, but generally 0.5 to 10% by weight, preferably 1 to 7% by weight, Preferably it is 2 to 5% by weight.
When the amount is less than 0.5% by weight, a sufficient change in color tone cannot be given to hair and the like, and when the amount is more than 10% by weight, a rough feel is given, so that the above range is appropriate.

[0029]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited to these Examples. In the following description, “parts” means parts by weight. Example 1 A liquid crystal compound having the following structure was prepared on a polyethylene terephthalate sheet at 120 ° C. using a blade.
The sheet was moved at a running speed of about 2 m / min while applying at a layer thickness of μm. After cooling, the liquid crystal compound was peeled off from the sheet using an orientation roller having a diameter of 10 cm, pulverized by a usual mill, and sieved using an analytical sieve having a mesh width of 50 μm. 5 parts of this cholesteric liquid crystal fine powder, 0.3 part of an anionic surfactant (polyoxyethylene (EO4) lauryl ether phosphate), 0.5 part of a nonionic surfactant (polyoxyethylene tridecyl ether), Group-containing vinyl polymer (Carbopol 981, BF Goodrich) 0.0
3 parts, amphoteric polymer compound (Yukaformer 202, manufactured by Mitsubishi Chemical Corporation) 2.5 parts, disodium edetate 0.1 part,
10 parts of ethanol and 80 parts of water were mixed, and the pH was adjusted to 7.5 with sodium hydroxide. Put 45 parts of the obtained mixture and about 1 part of stainless steel balls in a commercially available aerosol can,
Further, 5 parts of a propellant (liquefied petroleum gas 0.4 MPa) was charged to prepare an aerosol (foam) type hair cosmetic.

[0030]

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The obtained hair cosmetic composition was applied to ordinary black hair by spraying. The maximum reflection wavelength is 43 on the surface of the hair.
A vivid color having a pearl luster mainly composed of 6 nm blue-green was obtained. When the hair was exposed outdoors for half a day in fine weather, it turned red. The hair was then left for one hour in the dark, returning to its original bluish green color.
In addition, the spray containing the cholesteric liquid crystal fine powder could be easily washed off from the hair by ordinary shampoo.

Example 2 In this example, an example of a hair cosmetic using a cholesteric liquid crystal encapsulated therein is shown. (Preparation of cholesteric liquid crystal capsule) Ethyl acetate 19
3 parts of a cholesteric liquid crystal compound composed of a polymer of the following compound A / B = 50/50 and 10 parts of tricresyl phosphate were added and mixed. Next, Takenate D110N (manufactured by Takeda Pharmaceutical Co., Ltd.) is used as a wall material in this mixed solution.
7.6 parts were added and mixed to obtain a liquid (I). Next, the above solution (I) was added to a mixture of 46 parts of an 8% aqueous solution of phthalated gelatin, 17.5 parts of water, and 2 parts of a 10% aqueous solution of sodium dodecylbenzenesulfonate, and a homogenizer was used. The mixture was emulsified and dispersed at 5,000 rpm at 40 ° C. for 10 minutes. After 20 parts of water was added to the obtained emulsion to homogenize it, an encapsulation reaction was performed at 40 ° C. for 3 hours with stirring to obtain a capsule liquid A. The particle size of the capsule was 30-50 μm.

[0033]

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An aerosol-type hair cosmetic was prepared in the same manner as in Example 1, except that 10 parts of the above capsule liquid A was used instead of the cholesteric liquid crystal fine powder used in Example 1. The obtained hair cosmetic was applied to ordinary black hair by spraying. A vivid color having a pearl luster mainly composed of red was obtained at 30 ° C. on the surface of the hair. When the hair was left at 10 ° C. for 1 hour, the color changed to blue. When the hair was returned to room temperature and left for 1 hour, it returned to the original red color.

[0035]

As described above, the cosmetic of the present invention provides a new kind of color effect because an organic compound which selectively reflects light having an arbitrary wavelength in the visible region, particularly a cholesteric liquid crystal compound, is used as a pigment. The present invention can provide a cosmetic that varies in color tone depending on the angle at which the color tone is viewed, and that changes its color tone by light or heat after being applied to hair or the like.

Claims (3)

[Claims] 1. A cosmetic containing a cholesteric liquid crystal compound that selectively reflects light having an arbitrary wavelength in the visible region,
A cosmetic comprising a cholesteric liquid crystal compound in which the selective reflection wavelength of the cholesteric liquid crystal compound changes with light. 2. A cosmetic containing a cholesteric liquid crystal compound that selectively reflects light having an arbitrary wavelength in the visible region.
A cosmetic comprising a cholesteric liquid crystal compound in which the selective reflection wavelength of the cholesteric liquid crystal compound changes with temperature. 3. The cosmetic according to claim 1, wherein the cosmetic is a hair cosmetic.