Patent Application
20220071858
The present invention relates to a redispersible two-layer cosmetic.
Multilayer cosmetics are composed of multiple layers (for example, a powder layer and an aqueous layer, or an aqueous layer and an oil layer). Many different technologies for multilayer cosmetics continue to be developed because such multilayer cosmetics provide excellent aesthetic appearance and are very attractive for consumers.
Japanese Unexamined Patent Publication No. 2013-177366 (equivalent EP2810639B1), for example, discloses a redispersible powder-dispersed cosmetic comprising (A) succinic acid and/or its salt, (B) bentonite and (C) a hydrophilic surfactant. But in a two-layer cosmetic composed of an aqueous layer and a powder layer comprising specific powders such as bentonite, cellulose and a synthetic polymer, it is often the case that the components become adsorbed onto the skin due to the moistness of the powder layer, impacting the long-lasting moisturizing effect searched by the consumers.
Also, Japanese Unexamined Patent Publication No. 2007-126394 discloses a multilayer cosmetic comprising a copolymer obtained by polymerizing a specific polyethylene oxide macromonomer, a hydrophobic monomer and a crosslinkable monomer, with 5 to 40 mass % of a liquid oil, and with the surfactant content being within a specified range. Japanese Unexamined Patent Publication No. 2014-208634 discloses a multilayer cosmetic comprising the following components (a) to (d): (a) a nonvolatile hydrocarbon oil having a viscosity of 30 to 400 mm2/s at 25° C., (b) a silicone oil having a viscosity of 30 to 400 mm2/s at 25° C., (c) water and (d) an ester of isostearic acid and polyglycerin.
But such a two-layer cosmetic composed of an aqueous layer and an oil layer tends to produce an oily sticky feel, impacting the smoothness searched by the consumers.
So there is still a need for providing a two-layer cosmetic that is improved in terms of both long-lasting moisturizing effect and smoothness.
Research carried out by the present inventors has led to the discovery of a novel redispersible two-layer cosmetic composed of specific gel particles and an aqueous phase, and the two-layer cosmetic has been demonstrated to exhibit improved long-lasting moisturizing effect and smoothness.
The invention relates to a redispersible two-layer cosmetic comprising an aqueous phase and polysaccharide gel particles having a mean particle size of 0.1 to 1000 μm.
The expression ‘redispersible two-layer cosmetic’ according to the invention, means that the composition provides a good redispersibility of polysaccharide gel particles (bottom layer) in the aqueous phase (upper layer) when shaken for use while being able to give a clear supernatant when not-in-use. So, settling and dispersion of the gel particle in the aqueous phase takes place repeatedly through cycles of standing at rest (not-in-use) and agitation (shaken).
The term ‘two-layer’ cosmetic according to the invention, means that the composition presents two visually distinct layers, when it stands at rest (not-in-use), ie an upper layer comprising the aqueous phase and a bottom layer comprising the polysaccharide gel particles.
The redispersible two-layer cosmetic of the invention exhibits improved long-lasting moisturizing effect and smoothness.
The polysaccharide may be agar. In this case, as a gel particle, a pulverized form of an agar gel may be used and the agar gel is obtained by gelating the agar swelled with a gel-forming aqueous phase (second layer).
The viscosity of the two-layer cosmetic may be 1 cP to 200 cP at 25° C.
The aqueous phase may comprise a polyol or a mono-alcohol. The aqueous phase may also comprise an aryloxyalkanol such as phenoxyethanol.
With the invention it is possible to provide a redispersible two-layer cosmetic that is improved in terms of both long-lasting moisturizing effect and smoothness.
Embodiments of the invention will now be described. However, the present invention is not limited to the embodiments described below.
The redispersible two-layer cosmetic of this embodiment contains an aqueous phase (first layer, ie upper layer), and polysaccharide gel particles having a mean particle size of 0.1 to 1000 μm (second layer, ie bottom layer). As used herein, the term “two-layer cosmetic” refers to a cosmetic having two visually distinct layers when not-in-use, i.e a plurality of gel particles separate from the aqueous phase.
When the two-layer cosmetic of this embodiment undergoes a cycle of standing at rest (not-in-use) and agitation (shaken), settling and dispersion of the gel particles takes place in the aqueous phase. Specifically, during settling (for example, when approximately 100 mL is housed in a container with a capacity of 120 mL and allowed to stand for one day or longer), the gel particles settle in the aqueous phase, so that the two-layer cosmetic consists of a bottom layer formed by a plurality of gel particles aggregates, and an upper layer composed of the aqueous phase over the bottom layer. The gel particles are composed of components such that, under usual storage temperature (for example, room temperature, or 5 to 30° C.) and storage time (for example, 3 years) conditions for a two-layer cosmetic, they do not elute into the aqueous phase and lose their form, and the particles do not adhere together and form aggregates (masses). The aqueous phase may also be present between the gel particles. When agitated (shaken), however, the gel particles become dispersed in the aqueous phase, and therefore the two-layer cosmetic comprises the aqueous phase and the gel particles dispersed in the aqueous phase.
The aqueous phase may consist of water alone or it may comprise other water-soluble components in water. Water-soluble components are components that dissolve to at least 0.1 g per 100 g of water.
Water-soluble components comprise polyols, mono-alcohols (excluding those qualifying as preservatives), preservatives, perfumes, solubilizers, salting-out agents, pH regulators, surfactants, whitening agents, anti-inflammatory agents, colorants, and non-gelating polysaccharides (for example, xanthan gum, sodium hyaluronate, gum arabic, xanthan gum, guar gum and succinoglycan).
The valency of a polyol may be 2 to 4, or 2 to 3, for example. In other words, the polyol may comprise diols and/or triols. Examples of polyols comprise diols such as butylene glycol (1,3-butylene glycol), pentylene glycol, propanediol, dipropylene glycol, polyalkylene glycols (such as polyethylene glycol), and triols such as glycerin. These polyols may be used alone or in combinations of two or more.
When the aqueous phase comprises or consists of a polyol, the total polyol content may be 1 to 30 mass %, 5 to 20 mass % or 7 to 15 mass %, based on the total mass of the two-layer cosmetic. The term ‘mass %’ is also referred as % by weight.
Mono-alcohols (C1-C5) comprise ethanol, propanol, isopropanol and butanol. In a particular embodiment, the mono-alcohol is ethanol. These mono-alcohols may also be used alone or in combinations of two or more. When the aqueous phase comprises or consists of a mono-alcohol, the total mono-alcohol content may be 1 to 20 mass %, 2 to 15 mass % or 3 to 10 mass % based on the total mass of the two-layer cosmetic.
Preservatives comprise aryloxyalkanols such as phenoxyethanol, and ethylenediaminetetraacetic acid (EDTA) disodium, and ethylenediaminetetraacetic acid (EDTA) tetrasodium. The aqueous phase may comprise an aryloxyalkanol as the preservative, but it preferably comprises phenoxyethanol. These preservatives may also be used alone or in combinations of two or more. When the aqueous phase comprises a preservative, the preservative content may be 0.01 to 5 mass %, 0.01 to 2 mass %, 0.1 to 2 mass %, 0.5 to 2 mass % or 0.7 to 2 mass %, based on the total mass of the two-layer cosmetic.
Solubilizers comprise PPG-6 decyl tetradeceth-20, PPG-6 decyl tetradeceth-30, PEG-60 hydrogenated castor oil, PEG-80 hydrogenated castor oil, PEG-60 glyceryl isostearate, PEG-20 sorbitan cocoate and PEG-20 sorbitan isostearate. When the aqueous phase comprises a solubilizer, the total solubilizer content may be 0.01 to 5 mass %, 0.05 to 1 mass % or 0.05 to 0.5 mass %, based on the total mass of the two-layer cosmetic.
Salting-out agents comprise sodium chloride, potassium chloride, calcium chloride, sodium sulfate and magnesium sulfate. When the aqueous phase comprises a salting-out agent, the total salting-out agent content may be 0.1 to 10 mass %, 0.5 to 5 mass % or 0.7 to 2 mass %, based on the total mass of the two-layer cosmetic.
The aqueous phase content may be 85.0 to 99.9 mass % or 90.0 to 99.5 mass %, based on the total mass of the two-layer cosmetic.
The gel particles comprise a gellable polysaccharide and a solvent in the second layer for formation of the gel (a gel-forming aqueous phase of the second layer). Examples of gellable polysaccharides (hereunder also referred to simply as “polysaccharides”) comprise agar, carrageenan (such as kappa-carrageenan and iota-carrageenan), gellan gum, sodium alginate, tamarind gum, mannan and locust bean gum, and mixtures thereof. These polysaccharides may likewise be used alone or in combinations of two or more. The polysaccharide is preferably at least one selected from the group consisting of agar, carrageenan and gellan gum, and more preferably agar. The gel-forming aqueous phase may employ any of the components mentioned above for the aqueous phase of the first layer. The components used in the gel-forming aqueous phase may be the same as in the aqueous phase described above (first layer), or different ones. In a particular embodiment, the solvent used for formation of the polysaccharide gel is water.
Gel particles can be obtained by the following method, as an example. First, the gellable polysaccharide is swelled with the aqueous phase (second layer) by heating if necessary. The temperature for swelling the polysaccharide may be 70 to 100° C. or 80 to 90° C., for example. The polysaccharide may be swelled while being stirred under conditions of 1000 to 5000 rpm, for example. The swelled polysaccharide is allowed to stand for cooling, and then to be pulverized, or the swelled polysaccharide is cooled while being stirred, to obtain a polysaccharide gel particle having a mean particle size of 0.1 to 1000 μm. The pulverization can be carried out using a homogenizer, Disper mixer or blender, for example. The pulverization may alternatively be carried out by stirring at 5000 rpm to 20,000 rpm. A gelling agent (such as calcium chloride or potassium chloride) may also be used during the process of producing the gel particles. When a gelling agent is used for gelation of the polysaccharide, it is preferred to select one such that the jelly strength (or gelation strength) of the polysaccharide is between 500 g/cm2 and 1000 g/cm2 at a polysaccharide concentration of 1.5 mass %, for example. The gel particles do not have a thickening effect that is effective enough to be used as a thickening agent for cosmetics.
When agar is used as a polysaccharide, as gel particles a pulverized form of an agar gel may be used. As an agar gel, agar swelled with the gel-forming aqueous phase of the second layer and gelated may be used. The pulverized form of an agar gel is obtained by allowing the swelled agar to stand for cooling then pulverizing the same or by cooling while stirring the swelled agar.
When the polysaccharide is at least one selected from the group consisting of carrageenan, gellan gum, sodium alginate, tamarind gum, mannan and locust bean gum, the gel particles may be a pulverized form of the polysaccharide gel, a polysaccharide gel obtained by gelating the polysaccharide swelled with the gel-forming aqueous phase of the second layer. In this case, gelation may be carried out by adding a gelling agent.
The mean particle size of the gel particles may be 0.1 μm or greater, 1 μm or greater, 5 μm or greater, 10 μm or greater, 50 μm or greater, 60 μm or greater, 70 μm or greater or 80 μm or greater, and no greater than 1000 μm, no greater than 500 μm, no greater than 400 μm, no greater than 300 μm, no greater than 250 μm, no greater than 200 μm, no greater than 150 μm or no greater than 120 μm. In other words, the mean particle size of the gel particle may be 0.1 to 1000 μm, 1 to 500 μm, 5 to 400 μm, 10 to 300 μm, 50 to 250 μm, 60 to 200 μm, 70 to 150 μm or 80 to 120 μm. The term “mean particle size” as used herein is defined as the value measured using a Laser scattering particle size distribution analyzer. The mean particle size of the gel particles can be adjusted to within such ranges by altering the conditions under which the polysaccharide gel particles are produced (such as the pulverizing conditions).
When the polysaccharide is agar, the jelly strength (or gelation strength) of the polysaccharide may be 500 g/cm2 or greater, 600 g/cm2 or greater, 650 g/cm2 or greater or 700 g/cm2 or greater, and no greater than 1000 g/cm2, no greater than 900 g/cm2, no greater than 800 g/cm2 or no greater than 750 g/cm2, with a polysaccharide concentration of 1.5 mass %. From the viewpoint of superior smoothness, when the polysaccharide is agar its jelly strength (or gelation strength) may be between 500 g/cm2 and 1000 g/cm2, between 600 g/cm2 and 900 g/cm2, between 650 g/cm2 and 800 g/cm2 or between 700 g/cm2 and 800 g/cm2, at a polysaccharide concentration of 1.5 mass %.
The jelly strength (or gelation strength) is measured as a gel strength for an aqueous solution having a 1.5% polysaccharide concentration In other words, for the jelly strength measurement, the polysaccharide is weighed accurately, and deionized water is added thereto, thereby causing the polysaccharide to sufficiently absorb water. Subsequently, warm deionized water is added thereto to adjust the content, which is then subjected to a hot water bath to cause dissolution by heat. In order to make up water evaporating by heating, deionized water is used as a supplement to adjust the content, and the solution is caused to flow into a glass container in which a tape is wound around the upper portion thereof. The container is left to cool at room temperature, and then capped and left in a constant temperature chamber at 20° C. overnight. The tape is peeled off from the glass container, and then jelly around the periphery of the container that sticks out of the container is cut with a cutter and discarded. The strength of the cut surface of the obtained jelly is measured using a texture analyzer or the like. That is, a cylindrical plunger having an area of 1 cm2 is mounted on the cut surface, and the sample stage is moved at an appropriate lifting rate. In this manner, a force applied until the jelly breaks can be measured.
From the viewpoint of allowing the gel particle to settle more easily, the weight-average molecular weight of the polysaccharide may be 150,000 or greater, 200,000 or greater, 250,000 or greater or 300,000 or greater, and from the viewpoint of superior smoothness (minimally rough surface), it is preferably no greater than 500,000, no greater than 450,000, no greater than 400,000 or no greater than 350,000. The weight-average molecular weight of the polysaccharide may be between 150,000 and 500,000, between 150,000 and 450,000, between 150,000 and 400,000, between 150,000 and 350,000, between 200,000 and 500,000, between 200,000 and 450,000, between 200,000 and 400,000, between 200,000 and 350,000, between 250,000 and 500,000, between 250,000 and 450,000, between 250,000 and 400,000, between 250,000 and 350,000, between 300,000 and 500,000, between 300,000 and 450,000, between 300,000 and 400,000 or between 300,000 and 350,000.
The weight-average molecular weight of the polysaccharide can be measured by HPLC gel permeation chromatography. For example, after dissolving the polysaccharide in distilled water at 95 to 97° C., the solution is cooled to 50° C. to obtain a measuring sample, and the gel permeation chromatography measurement is conducted using this sample. One example of a liquid chromatography apparatus is LC-10AT VP or RID-10A by Shimadzu Corp., with a differential refractometer as the detector, TOSOH TSK-GEL for HPLC or TSK-GEL GMPWXL by Tosoh Corp. as the column and 0.1 M sodium nitrate as the developing solvent, and the measurement being conducted at a constant temperature. The weight-average molecular weight of agar is determined using pullulan of known molecular weight (Shodex STANDARD P-82, for example) as the standard sample. The standard sample is dissolved in distilled water, and measurement is performed by HPLC gel permeation chromatography under the same conditions.
The polysaccharide content may be 0.01 mass % or greater, 0.05 mass % or greater, 0.10 mass % or greater, 0.20 mass % or greater, 0.30 mass % or greater or 0.40 mass % or greater, and no greater than 2.0 mass %, no greater than 1.0 mass %, no greater than 0.8 mass % or no greater than 0.6 mass %, based on the total mass of the two-layer cosmetic. In other words, the polysaccharide content may be from 0.05 to 2.0 mass %, in particular from 0.10 to 1.0 mass %, or from 0.20 to 0.8 mass % or even from 0.40 to 0.6 mass %, based on the total mass of the two-layer cosmetic.
The polysaccharide gel particles content may be 5 mass % or greater, 10 mass % or greater or 15 mass % or greater, and no greater than 50 mass %, no greater than 30 mass % or no greater than 25 mass %, based on the total mass of the two-layer cosmetic. The polysaccharide gel particles content may be from 5 to 50 mass %, in particular from 10 to 30 mass % or even from 15 to 25 mass %, based on the total mass of the two-layer cosmetic.
The viscosity of the two-layer cosmetic may be no higher than 200 cP, no higher than 100 cP, no higher than 50 cP or lower than 10 cP, and it may be 1 cP or higher, or 5 cP or higher, for example, at 25° C. The viscosity of the two-layer cosmetic may be 1 cP to 200 cP, 1 cP to 100 cP, 1 cP to 50 cP, 1 cP to less than 10 cP, 5 cP to 200 cP, 5 cP to 100 cP, 5 cP to 50 cP or 5 cP to less than 10 cP, at 25° C.
The viscosity of the two-layer cosmetic may be measured based on the shear viscosity using a rotating viscometer (Rheolab QC by Anton Paar GmbH), under conditions of 100 rpm, 25° C. A viscosity in this range will improve the stability of the two-layer cosmetic and give it an excellent feel during use.
The redispersible two-layer cosmetic can be obtained, for example, by mixing (shaking) and stirring the aqueous phase of the first layer and gel particles of the second layer.
The redispersible two-layer cosmetic of this embodiment can be suitably used for a cosmetic water product, cleansing lotion, face cleanser, essence, makeup base, lotion mist, sunscreen or the like.
The present invention also relates to a cosmetic process for caring for and/or making-up keratinic materials comprising the application onto keratinic materials, in particular onto skin, of the redispersible two-layer cosmetic as defined in the invention.
By ‘keratinic materials’, it means skin and/or lips, preferably skin.
The redispersible two-layer cosmetic is generally shaken before use.
In particular, the redispersible two-layer cosmetic of the invention advantageously provides a long-lasting moisturizing effect and smoothness onto keratinic materials, in particular onto skin, on which it is applied.
The invention will now be illustrated by examples, with the understanding that the invention is not meant to be limited to these examples. Unless contrary indication, the % are mass % also referred as % by weight of total weight of the composition.
The following polysaccharides were prepared.
The jelly strength of agar and the weight-average molecular weight are the values measured by the above-mentioned method.
Polysaccharide gel particles were prepared from the polysaccharide by the following method. First, water (the gel-forming aqueous phase of the second layer) and the polysaccharide were combined, and while the combination was stirred at 90° C., 3000 rpm, the polysaccharide was swelled. When the agar was used as the polysaccharide, the swelled polysaccharide was allowed to stand for cooling to obtain an agar gel (polysaccharide concentration: 4 mass %). As a gelling agent, potassium chloride was added to the kappa carrageenan and mixed to obtain a kappa carrageenan gel (polysaccharide concentration: 4 mass %). As a gelling agent, calcium chloride was added to the gellan gum and mixed to obtain a gellan gum gel (polysaccharide concentration: 4 mass %). Water (the gel-forming aqueous phase of the second layer) was added to the gel which was then pulverized with a Waring blender at 18,000 rpm for 2 minutes to prepare polysaccharide gel particles (polysaccharide concentration: 2 mass %).
In Example 1 and Examples 4 to 9, the mean particle size of the agar gel particles was 100 μm, in Example 2 the mean particle size of the carrageenan gel particles was 100 μm, and in Example 3 the mean particle size of the gellan gum gel particles was 100 μm. The mean particle size of the gel particles was measured using a Laser scattering particle size distribution analyzer.
Aqueous phases (first layer) having the compositions listed in Tables 1 and 2 were added to the polysaccharide gel particles obtained by the method described above, and the mixtures were stirred to prepare two-layer cosmetics for the Examples. The polysaccharide contents of the two-layer cosmetics of the Examples were the amounts listed in Table 1 with respect to the total masses of the two-layer cosmetics.
Agar (trade name: Ina Agar CS-7, Ina Food Industry Co., Ltd.) and water were combined, and while the combination was stirred at 90° C., 3000 rpm, the ager was swelled. An aqueous phase (first layer) having the composition listed in Table 1 was added to the swelled agar and the mixture was stirred to prepare a cosmetic for Comparative Example 1 and 2. Bentonite and kaolin (powder second phase) were also mixed with an aqueous phase (first phase) having the composition listed in Table 1 to prepare a two-layer cosmetic for Comparative Example 3. Oil (second phase) having the composition listed in Table 1 were mixed with an aqueous phase (first phase) having the composition listed in Table 1 to prepare a two-layer cosmetic for Comparative Example 4. A cosmetic having the composition listed in Table 2 was also prepared as a cosmetic for Comparative Example 5.
The viscosities of the two-layer cosmetics were measured by the following method. The shear viscosity of each cosmetic was measured at 25° C. using a rotating viscometer (Rheolab QC by Anton Paar GmbH) (rotational speed: 100 rpm).
The cosmetics of the Examples and Comparative Examples were evaluated for “separation”, “re-dispersibility”, “long-lasting moisturizing effect” and “smoothness”, on the following scales. The “long-lasting moisturizing effect” and “smoothness” parameters were evaluated by a single use test on skin by an evaluation panel of cosmetic experts.
After mixing by shaking followed by standing at room temperature, the outer appearance was visually evaluated.
A: The interface between a uniform upper layer and a uniform lower layer was clearly observable after standing for half a day
B: The interface between a uniform upper layer and a uniform lower layer was clearly observable after standing for a full day
C: The interface between the upper layer and lower layer was observable but indistinct after shaking and standing for a full day, with non-uniformity of either the upper layer or lower layer
D: No observable interface between the upper layer and lower layer after shaking and standing for a full day
The mixture was shaken and allowed to stand for 1 month at 25° C., and then shaken again.
A: Uniformly dispersed after shaking ≤10 times
B: Uniformly dispersed after shaking 10 to ≤20 times
C: Dispersed but non-uniform after ≥20 times
D: No re-dispersion
A: Very notable long-lasting moisturizing effect
B: Notable long-lasting moisturizing effect
C: Virtually no notable long-lasting moisturizing effect
D: Absolutely no notable long-lasting moisturizing effect
A: Very notable smoothness
B: Notable smoothness
C: Virtually no notable smoothness
D: Absolutely no notable smoothness
These results showed that the redispersible two-layer cosmetic comprising an aqueous phase and a polysaccharide gel particles having a mean particle size of 0.1 to 1000 μm according to the invention are well redispersible and have improved long-lasting moisturizing effect and smoothness in comparison to other two-layer cosmetic known from prior art.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2018/001593 | 12/19/2018 | WO | 00 |
