Inner phase thickened water-in-oil cosmetic composition

Abstract

Provided is a water-in-oil cosmetic composition comprising one or more thickening agents selected from the group consisting of sodium polyacrylate starch, polyacrylate crosspolymer-6, xanthan gum and locust bean gum in an inner phase. The water-in-oil cosmetic composition of the present invention brings improvements to time-related changes in preparation stability by means of inner phase thickening controlling the flow properties of an aqueous phase, and controls the size of emulsified particles by means of inner phase thickening, and as a result the invention has outstanding thixotropic characteristics and outstanding initial spreadability and has outstanding durability and, in addition, the invention provides both a fresh-cream-like soft feel in use and a liquid-like light feel in use.

Claims

1. A method for enhancing thixotropy of a cosmetic composition when applying the cosmetic composition onto a skin comprising adding at least one thickening agent selected from the group consisting of sodium polyacrylate starch and polyacrylate crosspolymer-6 to the cosmetic composition, wherein the cosmetic composition is a water in oil type cosmetic composition, and the thickening agent is added to an aqueous phase as an inner phase of the cosmetic composition.

2. The method according to claim 1, wherein the thickening agent is used in an amount of 0.01-5.0 wt % based on the total weight of the composition.

3. The method according to claim 1, wherein the composition is a makeup cosmetic composition.

4. The method according to claim 1, wherein the composition does not include a dispersant or a wax.

5. The method according to claim 1, wherein thixotropy is determined by a rheometer.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an SEM (scanning electron microscopy) image (a) and particle size distribution graph (b) of sodium polyacrylate starch contained in the cosmetic composition according to an embodiment of the present disclosure.

(2) FIG. 2 is a graph illustrating the thixotropic properties of the cosmetic composition according to an embodiment of the present disclosure.

(3) FIG. 3 to FIG. 5 are electron microscopy images of the cosmetic composition according to an embodiment of the present disclosure.

BEST MODE

(4) Hereinafter, exemplary embodiments now will be described more detail to provide the present disclosure fully understood to carry out by those skilled in the art.

(5) In an aspect, there is provided a cosmetic composition. The cosmetic composition is a water in oil type cosmetic composition including an outer phase and an inner phase, wherein the inner phase includes at least one thickening agent selected from the group consisting of sodium polyacrylate starch, polyacrylate crosspolymer-6, xanthan gum and locust bean gum.

(6) The water in oil type emulsion makeup cosmetic composition according to the present disclosure uses inner phase thickening to control the flowability of an aqueous phase. It is shown that such inner phase thickening minimizes variations in formulation stability with time.

(7) Water-soluble thickening agents may be classified into inorganic thickening agents including inorganic metal oxides and organic thickening agents including water-soluble polymer materials. According to an embodiment, water-soluble inorganic thickening agents having great possibility of skin allergy are not used but water-soluble organic thickening agents of polysaccharides are used.

(8) The thickening agent may be at least one selected from the group consisting of sodium polyacrylate starch, polyacrylate crosspolymer-6, xanthan gum and locust bean gum. More preferably, the thickening agent may be at least one of sodium polyacrylate starch and polyacrylate crosspolymer-6. Most preferably, the thickening agent may be sodium polyacrylate starch. However, any thickening agent may be used with no particular limitation, as long as it causes an increase in viscosity. FIG. 1 shows an SEM image (a) and particle size distribution graph (b) of sodium polyacrylate starch. After determining the average particle size of sodium polyacrylate starch by Mastersizer, it is 12 μm.

(9) The thickening agent may be used in an amount of 0.01-5.0 wt % based on the total weight of the composition. More preferably, it may be used in an amount of 0.05-1.0 wt %. When the thickening agent is used in an amount less than 0.01 wt %, it is not possible to obtain a sufficient thickening effect. When the thickening agent is used in an amount greater than 5.0 wt %, the viscosity of aqueous phase increases excessively, and thus the composition takes the form of hard solid gel, has high stickiness and does not provide properties as a makeup cosmetic composition any longer. Moreover, in the latter case, the composition undergoes pigment agglomeration upon emulsification and has poor stability due to its unstable emulsion state.

(10) The composition according to the present disclosure has thixotropy. Thixotropic properties, also called thixotropy, are referred to as properties including an increase in flowability caused by friction and a drop in flowability upon extinction of friction. By virtue of such thixotropy, the composition according to the present disclosure shows increased flowability upon friction against the skin when applying it to the skin, and is spread on the skin softly and smoothly, thereby providing excellent spreadability and feel in use. After the skin application, the composition according to the present disclosure has decreased flowability, thereby providing excellent durability. Particularly, the composition according to the present disclosure does not use a dispersant and wax but is based on inner phase thickening to control the flowability. Thus, the composition according to the present disclosure is produced in a simple manner, and has a light feel in use and high durability.

(11) Pigments used in water in oil emulsion may be classified into water-based dispersion pigments and oil-based dispersion pigments, depending on dispersed phases of pigments. In general, in the case of water in oil emulsion, a pigment coated with alkylsilane or dimethicone is dispersed into an oil-based outer phase. In this case, the pigment is positioned at the outer part of emulsion, and thus is more stable as compared to the dispersion into a water-based inner phase. However, when the pigment is dispersed into the water-based inner phase rather than oil-based outer phase, it is possible to carry out dispersion of pigment in a greater amount more homogeneously. In fact, it has been reported that oil phase dispersion causes significant filling-up and aqueous phase (inner phase) dispersion improves such filling-up.

(12) Therefore, according to the present disclosure, the pigment is dispersed into an aqueous phase. Although there is no particular limitation in pigments for this purpose, a silica-coated pigment is used preferably. The surface of pigment is provided with hydrophilic properties by virtue of such silica coating, thereby ensuring dispersibility.

(13) There is no particular limitation in the formulation of cosmetic composition according to the present disclosure, and any formulation may be selected suitably as desired. For example, the cosmetic composition may be provided as at least one formulation selected from the group consisting of skin lotion, skin softener, skin toner, astringent, lotion, milk lotion, moisture lotion, nourishing lotion, massage cream, nourishing cream, moisture cream, hand cream, foundation, makeup base, primer, essence, nourishing essence, pack, soap, cleansing foam, cleansing lotion, cleansing cream, body lotion and body cleanser. Preferably, the formulation is foundation, makeup base or primer, but is not limited thereto.

(14) When the cosmetic composition is provided as a formulation of paste, cream or gel, animal fibers, vegetable fibers, wax, paraffin, starch, tragacanth, cellulose derivatives, polyethylene glycol, silicone, bentonite, silica, talk or zinc oxide may be used as a carrier ingredient.

(15) When the cosmetic composition is provided as a formulation of powder or spray, lactose, talc, silica, aluminum hydroxide, calcium silicate or polyamide powder may be used as a carrier ingredient. Particularly, in the case of spray, a propellant, such as chlorofluorohydrocarbon, propane/butane or dimethyl ether, may be further used.

(16) When the cosmetic composition is provided as a formulation of solution or emulsion, a solvent, solvating agent or emulsifier may be used as a carrier ingredient, and particular examples thereof include water, ethanol, isopropanol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol oil, glycerol fatty ester, polyethylene glycol or sorbitan fatty acid ester.

(17) When the cosmetic composition is provided as a formulation of suspension, a liquid diluent such as water, ethanol or propylene glycol, a suspending agent such as ethoxylated isostearyl alcohol, polyoxyethylene sorbitol ester or polyoxyethylene sorbitan ester, microcrystalline cellulose, aluminum meta-hydroxide, bentonite, agar, tragacanth or the like may be used.

(18) When the cosmetic composition is provided a formulation of surfactant-containing cleanser, aliphatic alcohol sulfate, aliphatic alcohol ether sulfate, sulfosuccinic acid monoester, isethionate, imidazolinium derivative, methyl taurate, sarcosinate, fatty acid amide ether sulfate, alkylamidobetain, aliphatic alcohol, fatty acid glyceride, fatty acid diethanol amide, vegetable oil, linoline derivative or ethoxylated glycerol fatty acid ester or the like may be used as a carrier ingredient.

(19) The cosmetic composition may further include functional additives and other ingredients used in conventional cosmetic compositions. Such functional additives include any ingredients selected from the group consisting of water-soluble vitamins, oil-soluble vitamins, polymeric peptides, polysaccharides, spingolipids and seaweed extract.

(20) The cosmetic composition may be formulated by using any desired ingredients used in conventional cosmetic compositions in addition to such functional additives. Such ingredients may include fat and oil ingredients, moisturizing agents, emollients, surfactants, organic and inorganic pigments, organic powder, UV absorbing agents, preservatives, sterilizing agents, antioxidants, plant extract, pH modifiers, alcohols, colorants, fragrant, blood circulation accelerators, coolants, antiperspirants, purified water or the like.

(21) The present disclosure now will be described in more detail hereinafter with reference to Examples. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth therein.

Examples 1-4 and Comparative Example 1

(22) Water in oil emulsion formulations of Comparative Example 1 and Examples 1-4 are obtained by using the formulations as shown in Table 1 in the conventional manner. Comparative Example 1 is the control using no aqueous phase thickening agent, and Examples 1-4 are obtained by using an aqueous phase thickening agent.

(23) TABLE-US-00001 TABLE 1 Item Ingredients Comp. Ex. 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Emulsifier LaurylPEG-9 3.0 3.0 3.0 3.0 3.0 polydimethylsiloxyethyl dimethicone Sorbitan isostearate 1.0 1.0 1.0 1.0 1.0 Oil phase Decamethylcyclopenta 20.0  20.0  20.0  20.0  20.0  ingredients siloxane Dicaprylyl carbonate 10.00 10.00 10.00 10.00 10.00 Squalane 10.00 10.00 10.00 10.00 10.00 Oil phase Distearmonium hectorite 1.0 1.0 1.0 1.0 1.0 thickening agent Aqueous Purified water To 100 To 100 To 100 To 100 To 100 phase Butylene glycol 4.0 4.0 4.0 4.0 4.0 ingredients Glycerin 4.0 4.0 4.0 4.0 4.0 Phenoxyethanol 0.3 0.3 0.3 0.3 0.3 Aqueous Xanthan gum — 0.5 — — — phase Locust bean gum — — 0.5 — — thickening Polyacrylate — — — 0.5 — agent crosspolymer-6 Sodium polyacrylate — — — — 0.5 starch

[Test Example 1] Test for Determining Stability Depending on Aqueous Phase Thickening Agent

(24) The emulsion stability and variations in hardness with time are evaluated depending on the particular type of water-soluble thickening agent by using Examples 1-4 and Comparative Example 1.

(25) Evaluation of emulsion stability is carried out by measuring the stability for 1 week in a shaking incubator capable of temperature control. One temperature cycle includes −10° C., 30° C. and 45° C. each for 8 hours. Emulsion stability is determined for 7 days in 1 cycle per day by observing occurrence of oil separation, band formation, precipitation, etc. For all samples, data are acquired five times to obtain results. When a sample shows no abnormality for 5 times, it is expressed by ∘. When a sample shows abnormality for 1˜2 times, it is expressed by Δ. When a sample shows abnormality for 3 times or more, it is expressed by X. Pigment dispersibility is determined by a dispersion degree of pigment in an aqueous phase, and evaluated according to the same criteria as the emulsion stability.

(26) Variations in hardness with time are determined by measuring the hardness of a sample by Rheometer (CR-500DX, Sun Scientific), after the prepared sample is stored in a constant-temperature bath at 30° C. Hardness is compared between the sample after preparation and the sample after 1 week to determine the stability. The results are shown in Table 2.

(27) TABLE-US-00002 TABLE 2 Comp. Ex. 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 1 2 3 4 5 Emulsion stability X Δ Δ ◯ ◯ Variations in −28% −15% −8% +9.5% +13.6% hardness with time

(28) As can be seen from Table 2, only Comparative 1 using no aqueous phase thickening shows poor stability. Examples 1-4 substantially maintain their stabilities. In addition, as compared to Examples 1 and 2 (xanthan gum, locust bean gum), thickening in Examples 3 and 4 (sodium polyacrylate starch, polyacrylate crosspolymer-6) provides higher stability. In terms of variations in hardness with time, Examples 3 and 4 maintain their most stable states with no drop in hardness.

[Test Example 2] Images Taken by Electron Microscope

(29) Comparative Example 1, and Examples 3 and 4 are imaged by electron microscopy. The results of Comparative Example 1, Example 3 and Example 4 are shown in FIG. 3, FIG. 4 and FIG. 5, respectively.

(30) As can be seen from FIG. 3 to FIG. 5, the emulsion particles of Example 4 form a bi-modal condition and realize a feel in use caused by easy collapse of the particles.

[Preparation Example] Preparation of Foundation

(31) A pigment is added to each of Comparative Example 1 and Example 4 (according to the composition as shown in Table 3) to obtain water in oil emulsion foundation in the conventional manner. Comparative Example 1 is the control using no aqueous phase thickening agent. Example 4 having high emulsion stability and showing the lowest variation in hardness with time is used.

(32) TABLE-US-00003 TABLE 3 Comp. Item Ingredient Ex. 1 Ex. 4 Emulsifier LaurylPEG-9 3.0 3.0 polydimethylsiloxyethyl- dimethicone Sorbitan isostearate 1.0 1.0 Oil phase Decamethylcyclopentasiloxane 20.0 20.0 ingredients Dicaprylyl carbonate 10.00 10.00 Squalane 10.00 10.00 Oil phase Distearmonium hectorite 1.0 1.0 thickening agent Pigment Oil phase pigment 10.0 10.0 Aqueous phase Purified water To 100 To 100 ingredients Butylene glycol 4.0 4.0 Glycerin 4.0 4.0 Phenoxyethanol 0.3 0.3 Aqueous phase Sodium Polyacrylate starch — 0.5 thickening agent

[Test Example 3] Test for Determining Thixotropy, Easy Spreadability and Uniform Applicability

(33) The foundation obtained from the above Preparation Example is observed in terms of its thixotropy, easy spreadability and uniform applicability. The thixotropy is determined by RHEOMETER AR2000 (TA Instruments, England) and the results are shown in Table 4 and FIG. 2. Easy spreadability and uniform applicability are determined based on the test scores from professional panels by taking score 5 as the highest score. The results are shown in Table 4.

(34) TABLE-US-00004 TABLE 4 Easy Uniform Item Thixotropy spreadability Applicability Comp. Ex. 1 poor 3.1 2.8 Ex. 4 High 4.8 4.6

(35) As can be seen from Table 4 and FIG. 2, the foundation using Example 4 provides higher thixotropy, easy spreadability and uniform applicability as compared to the foundation using Comparative Example 1.