JP7422481B2 - composite powder - Google Patents

Description

The present invention relates to a novel composite powder. Specifically, by supporting an aqueous solution containing a water-affinity functional component in the pores of a hydrophobized metal oxide airgel powder having specific physical properties, it can be used, for example, as an additive to powder cosmetics. The purpose is to provide a composite powder that can exhibit functions not seen before.

Airgel is a material in which the liquid contained in the gel is dried while suppressing the shrinkage caused by drying (drying shrinkage).It is a material with a high porosity of 60% or more, and its characteristics are It is used for various purposes.

For example, as a method for producing silica airgel having a metal oxide, for example, silica, as a skeleton, a hydrogel obtained by polycondensing a hydrolysis product of an alkoxysilane, or a hydrogel formed by neutralizing an alkali metal silicate. There are known methods of drying a hydrogel obtained by gelling a sol while suppressing shrinkage (drying shrinkage), such as drying a dispersion medium under supercritical conditions (Patent Documents 1 to 4).

The metal oxide airgel thus obtained has various uses, one of which is as a cosmetic material (see Patent Document 5). For example, it is used in powder form as a foundation material. In this application, it is stated that airgel with a high oil absorption capacity can absorb a large amount of sebum that causes shine, so that the appearance of makeup can be maintained for a long time.

On the other hand, in cosmetic applications, the pursuit of functionality is an eternal theme, and even hydrophobized metal oxide airgel powders with high oil-absorbing properties are required to have functions that go beyond the ability to remove sebum.

US Patent No. 4402927 Japanese Patent Application Publication No. 10-236817 Japanese Patent Application Publication No. 06-040714 Japanese Patent Application Publication No. 07-257918 Japanese Patent Application Publication No. 2014-88307

Therefore, an object of the present invention is to provide a composite powder that is capable of exhibiting an unprecedented function in addition to the function of absorbing oil such as sebum in a hydrophobized metal oxide airgel powder.

As a result of extensive research to achieve the above object, the present inventors discovered that an aqueous solution was created in the pores of a hydrophobized metal oxide airgel powder that had been adjusted to a specific degree of hydrophobization. We have discovered a phenomenon in which a composite powder carrying . By selecting a functional component, such as hyaluronic acid or glycerin, which has a moisturizing effect, as the solute in the aqueous solution that is present in the pores, the hydrophobic interaction of the hydrophobized metal oxide airgel powder and the associated fine particles are achieved. It was confirmed that due to the substitution effect inside the pores, it exhibits an unprecedented function of absorbing oil (sebum) secreted from the skin and releasing functional ingredients such as moisturizing ingredients. The present invention has now been completed.

That is, according to the present invention, a water-philic functional component is supported in the state of an aqueous solution in the pores of a hydrophobized metal oxide airgel powder having an average particle size of 1 to 30 μm and an M value of 20 to 60. A composite powder is provided.

The hydrophobized metal oxide airgel powder has a pore volume of 0.5 to 8 ml/g, a peak value of pore radius of 10 to 40 nm, and a specific surface area of 350 to 1000 m ² /g is preferred.

Moreover, it is preferable that the hydrophobized metal oxide is silica.

Furthermore, it is preferable that the average circularity of the hydrophobized metal oxide airgel powder is spherical with an average circularity of 0.8 or more.

In the present invention, in order to fully exhibit the release effect of the functional component, the amount of aqueous solution supported in the pores of the hydrophobized metal oxide airgel powder must be at least 10% by volume of the total pore volume. It is preferable that there be.

The composite powder of the present invention having the above characteristics is useful as an additive for powder cosmetics, and in particular, by selecting a moisturizing ingredient that has a moisturizing function as a functional ingredient, the composite powder of the present invention can be used as an additive for powder cosmetics. It can exhibit the property of releasing the above-mentioned moisturizing ingredients at the same time as it absorbs the water.

The composite powder of the present invention has the ability to simultaneously absorb oil by supporting an aqueous solution containing a water-friendly functional component in the pores of a hydrophobized metal oxide airgel powder with specific hydrophobicity. It exhibits an unprecedented function of releasing an aqueous solution containing sexual components.

Therefore, for example, it is used as a component of a powder cosmetic, more specifically, a solid foundation, and is loaded with an aqueous solution containing, for example, hyaluronic acid or glycerin, which have a moisturizing effect, as the above-mentioned functional ingredients. After applying foundation to the skin, it absorbs sebum from the skin to prevent stickiness after application, and releases an aqueous solution containing hyaluronic acid and glycerin to maintain skin moisture for a long time. Cosmetics can be realized.

The forms shown below are examples of the present invention, and the present invention is not limited to these forms. Furthermore, unless otherwise specified, the notation "A to B" in a numerical range means "above A and below B." In such a notation, if a unit is attached only to the numerical value B, the unit shall also be applied to the numerical value A.

[Composite powder]
In the composite powder of the present invention, the metal element constituting the hydrophobized metal oxide airgel powder is not particularly limited, and may be any metal element that constitutes an oxide that is stable at room temperature, normal pressure, and in the atmosphere. . Specific examples of such metal oxides include silica (silicon dioxide), alumina, titania, zirconia, magnesia (MgO), iron oxide, copper oxide, zinc oxide, tin oxide, tungsten oxide, vanadium oxide, etc. Examples include oxides and composite oxides containing two or more of these metal elements (eg, silica-alumina, silica-titania, silica-titania-zirconia, etc.). Further, in the case of a composite oxide, it is also possible for the single oxide to contain an alkali metal or an alkaline earth metal (from the fourth period (Ca) of the periodic law), which are relatively sensitive to moisture, as a constituent metal element.

Among the metal oxides that can be used in the present invention, silica or a composite oxide containing silica as a main component is preferred because it is lightweight and can have a lower bulk density, and is inexpensive and easily available. When a certain composite oxide "mainly contains silica", it means that the molar ratio of silicon (Si) in the group of elements other than oxygen contained in the composite oxide is 50% or more and less than 100%. The molar ratio is preferably 65% or more, more preferably 75% or more, and still more preferably 80% or more.

When using a composite oxide containing silica as a main component, preferred metal elements other than silicon include Group II metals of the periodic table such as magnesium, calcium, strontium, and barium; aluminum, yttrium, indium, Examples include Group III metals of the periodic table such as boron and lanthanum (boron is treated as a metal element); and metals of Group IV of the periodic table such as titanium, zirconium, germanium, and tin. Among these, Al, Ti, and Zr can be particularly preferably employed. The composite oxide containing silica as a main component may contain two or more metal elements in addition to silicon.

The hydrophobized metal oxide airgel powder of the present invention has a median diameter (D50) in the range of 1 to 30 μm in particle size distribution measured by laser diffraction. Therefore, when used as an additive in cosmetics, it retains its appearance well and provides a smooth texture. The median diameter is more preferably in the range of 1 to 20 μm, particularly preferably 5 to 20 μm.

It is important that the hydrophobized metal oxide airgel powder in the present invention is hydrophobized. The degree of hydrophobization of the hydrophobized metal oxide airgel powder is specified by the M value.

Here, the M value is measured by the following method, taking advantage of the fact that the hydrophobized metal oxide airgel powder floats in water but is completely suspended in methanol.

That is, 0.2 g of the hydrophobized metal oxide airgel powder was added to 50 mL of water in a 250 mL beaker, and methanol was dropped into the beaker from a buret until the entire amount of silica was suspended. At this time, methanol was introduced into the liquid using a tube so as not to come into direct contact with the powder, and the solution in the beaker was constantly stirred with a magnetic stirrer. The time point when the entire amount of the hydrophobized metal oxide airgel powder was suspended in the solution was defined as the end point, and the value of the volume percentage of methanol in the liquid mixture in the beaker at the end point was defined as the M value.

In the present invention, it is important that the above M value of the hydrophobized metal oxide airgel powder is 20 to 60% by volume, preferably 30 to 50% by volume. That is, when the M value of the hydrophobized metal oxide airgel powder is less than 20% by volume, the hydrophobicity (oleophilicity) decreases, and the oil absorbency decreases when it comes into contact with oil, and the object of the present invention is becomes difficult to achieve. In addition, when the M value exceeds 60% by volume, it becomes difficult to support a sufficient amount of an aqueous solution containing a water-compatible functional component in the pores, and even if it is possible to support such an aqueous solution, It is also difficult to stably hold it within the pores.

A specific example of a mode in which hydrophobicity is imparted to the hydrophobized metal oxide airgel powder is a mode in which an organic silyl group is introduced to the surface by being treated with a silylating agent. . Specific examples of the above-mentioned silylating agent are shown in the manufacturing method described below.

The hydrophobized metal oxide airgel powder of the present invention preferably has a pore volume of 0.5 to 8 mL/g. The lower limit is more preferably 2.5 mL/g or more, particularly 3 mL/g or more. Moreover, it is more preferable that the upper limit is 6 mL/g or less. If the pore volume is less than 0.5 mL/g, a sufficient amount of an aqueous solution containing a water-compatible functional component cannot be supported, and the release effect of the functional component tends to decrease. There is. Further, although a higher pore volume is preferable, it is difficult to obtain a pore volume larger than 8 mL/g.

The above pore volume was determined by obtaining an adsorption isotherm and using the BJH method (Barrett, E.P.; Joyner, L.G.; Halenda, P.P., J. Am. Chem. Soc. 73, 373 (1951 ) (hereinafter sometimes referred to as "BJH pore volume").The pores measured by this method are pores with a radius of 1 to 100 nm, and the pores in this range are The integrated value of the pore volume is the pore volume in the present invention.

It is recommended that the hydrophobized metal oxide airgel powder of the present invention has a peak pore radius of 10 to 40 nm, preferably 10 to 30 nm. That is, when the pore radius is smaller than 5 nm, it tends to be difficult to support an aqueous solution containing a water-compatible functional component, and when the pore radius exceeds 50 nm, oil content in the pores tends to be difficult to support. As a result, it tends to be difficult to sufficiently release an aqueous solution containing a water-compatible functional component.

The hydrophobized metal oxide airgel powder of the present invention having a sharp pore size distribution generally has a pore radius of 5 to 50 nm, particularly 70% or more by volume of the total pore volume within the range of 10 to 40 nm. There are pores.

In the present invention, the peak and range of the pore radius are determined by the cumulative pore volume (volume) obtained by analyzing the adsorption isotherm on the adsorption side obtained in the same manner as above using the BJH method. distribution curve).

In the present invention, the specific surface area (BET specific surface area) measured by the BET method of the hydrophobized metal oxide airgel powder having the above-mentioned characteristic pores is generally 350 to 1000 m ² /g, preferably 400 to 850 m ² /g is preferable.

Here, the specific surface area by the above BET method is determined by drying the sample to be measured at a temperature of 200°C for 3 hours or more under a vacuum of 1 kPa or less, and then applying an adsorption isotherm of only the nitrogen adsorption side at liquid nitrogen temperature. This is the value obtained by acquiring and analyzing it using the BET method.

In the present invention, since the hydrophobized metal oxide airgel powder has a large specific surface area and pore volume as described above, its oil absorption amount is usually 200 mL/100 g or more. A more preferable oil absorption amount is 300 mL/100 g or more, further preferably 350 mL/100 g or more, and particularly preferably 400 mL/100 g or more. The upper limit is not particularly limited, but in consideration of particle strength, it is preferably 800 mL/100 g or less, more preferably 700 mL/100 g or less. The oil absorption amount is a value measured by the method described in JIS K5101-13-1 "Refined linseed oil method".

In the present invention, the shape of the particles constituting the hydrophobized metal oxide airgel powder is not particularly limited, but the average circularity is preferably 0.8 or more, particularly preferably 0.85 or more. .

The above-mentioned "average circularity" refers to the following for each particle, using a scanning electron microscope (SEM) to obtain an SEM image with secondary electron detection, low accelerating voltage (1 kV to 3 kV), and 1000x magnification. A value C (circularity) defined by formula (1) is obtained (image analysis), and this circularity C is calculated as an arithmetic average value for 2000 or more particles (image analysis method). At this time, a particle group forming one aggregated particle is counted as one particle.

C=4πS/L ² (1)
In the above formula (1), S represents the area (projected area) that the particle occupies in the image. L represents the length of the outer periphery (perimeter length) of the particle in the image.

As the average circularity becomes larger than 0.8 and approaches 1, each particle becomes closer to a perfect sphere, and the number of aggregated particles decreases. Therefore, if the average circularity is high, rolling properties will be better when used as a cosmetic additive, and an excellent texture will be obtained.

[Aqueous solution containing water-compatible functional components]
The most important feature of the composite powder of the present invention is that the pores of the hydrophobized metal oxide airgel powder support an aqueous solution containing a water-affinity functional component. That is, most of the conventional usage modes of hydrophobized metal oxide airgel powder utilized the characteristics of the powder having high oil absorption, but the composite powder of the present invention uses the specific hydrophobization By supporting a functional aqueous solution in the pores of the metal oxide airgel powder, it exhibits an unprecedented function of absorbing oil when it comes into contact with it and releasing the aqueous solution contained therein. do.

Therefore, the water-friendly functional component that serves as the solute in the aqueous solution is appropriately determined depending on the application. For example, in the application of cosmetics, the above-mentioned water-friendly functional ingredients include those for the purpose of preventing skin roughness, anti-aging, whitening, hair growth, acne care, prevention of UV damage, slimming, irritation relief, anti-inflammation, etc. It will be done.

The above-mentioned products aimed at preventing rough skin include moisturizers, vitamins, and the above-mentioned anti-aging products include ultraviolet absorbers, antioxidants, humectants, cell activators, blood flow promoters, and dermal matrix. Regenerating ingredients, α-hydroxy acids, and the above-mentioned whitening agents include melanin production inhibitors, endothelin action inhibitors, melanin pigment production-inducing factor inhibitors, melanin reduction agents, turnover promoters, and the above-mentioned hair growth agents. Examples of these include blood circulation promoters, hair follicle activators, anti-dandruff agents, and itch improving agents; examples of the above-mentioned acne care agents include keratolytic agents, sebaceous gland hyperfunction inhibitors, active oxygen scavengers, Antibacterial and bactericidal agents, those aimed at preventing ultraviolet damage include ultraviolet absorbers, active oxygen generation inhibitors, wrinkle suppressants, and those aimed at slimming include lipolysis promoters, blood circulation promoters, Examples of firming agents and those aimed at alleviating irritation and anti-inflammation include surfactant-based irritation alleviating agents, barrier function maintaining agents, and the like.

More specific examples of the above functional components include the following.

[Moisturizer] Polyhydric alcohols other than 1,2-alkanediol such as ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butylene glycol, glycerin, polyglycerin; glucose, maltose, maltitol, scroll , mannitol, sorbitol, xylitol, etc.; sugar derivatives such as polyoxyethylene methyl glucoside, polyoxypropylene methyl glucoside; polysaccharides such as dextrin, hyaluronic acid, chondroitin sulfate; amino acids such as glycine, alanine, serine, arginine, glutamic acid, etc. Polypeptides such as collagen; Organic acid salts such as sodium citrate, sodium lactate, and sodium malate.

[Vitamins] Vitamin B6 group, nicotinamide, calcium pantothenate, biotin, vitamin C group, etc.

[Ultraviolet absorber] Examples of substances that can be dispersed or dissolved in water include glycol salicylate, hydroxymethoxybenzophenone sulfonic acid, sodium hydroxymethoxybenzophenone sulfonate, sodium dihydroxydimethoxybenzophenone disulfonate, terephthalylidene dicanfursulfonic acid, methylene bisbenzo Triazolyltetramethylbutylphenol, phenylbenzimidazole sulfonic acid, etc.

[Antioxidants] Vitamins (B2, C), carotenoids (α-carotene, β-carotene, astaxanthin), polyphenols (phlorotannin, anthocyanin, etc.), various plant ingredients, as well as lactoferrin, ergothioneine, etc.

[Antioxidants] Ascorbic acid, gallic acid esters, etc.

[Cell activators] Collagen, elastin, yeast extract, lactic acid bacteria extract, reishi extract, etc.

[Blood flow promoters] Plant extracts such as ginkgo biloba extract, Japanese cabbage extract, horse chestnut extract, etc., carpronium chloride, cephalanthine, etc., vitamin E and its derivatives, capsicum tincture, dextran sodium sulfate, extracts such as carrot extract and seaweed, etc.

[Dermal matrix regeneration ingredients] Vitamin C derivatives, ginger extract, etc.

[The above α-hydroxy acid] Glycolic acid, lactic acid, salicylic acid, acetic acid, pyruvic acid, citric acid, etc.

[Melanin production inhibitors] Arbutin, sagebrush extract, peony root extract, licorice root extract, kojic acid, placenta extract, potassium 4-methoxysalicylate, etc.

[Endothelin action inhibitor] Chamomile extract, etc.

[Melanin pigment production inducing factor inhibitor] Tranexamic acid, cetyl tranexamate HCL, etc.

[Melanin reducing agent] Ascorbic acid, hydroquinone, etc.

[Turnover accelerator] Ascorbic acid glucoside, ascorbyl Mg phosphate, sodium ascorbyl phosphate, ascorbyl ethyl, disodium ascorbic acid sulfate, glyceryl ascorbic acid, adenosine monophosphate disodium OT, proteoglycan, etc.

[Hair follicle activator] Pantothenic acid and its derivatives, placenta extract, biotin, photosensor 301, 6-benzylaminopurine, etc.

[Anti-dandruff agents] Benzalkonium chloride, benzethonium chloride, piroctone olamine, etc.

[Itch improving agent] Dipotassium glycyrrhizinate, etc.

[Stratum corneum solubilizer] Sulfur, salicylic acid, glycolic acid, resorcinol, etc.

[Sebaceous gland hyperfunction suppressant] Plant-derived ingredients such as aloe, licorice, salamander, and rosemary, nicotinic acid, vitamin B6, etc.

[Active oxygen scavenger] Magnesium ascorbyl phosphate, ascorbyl tetra-2-hexyldecanoate, etc.

[Antibacterial/sterilizing agents] Benzelkonium chloride, benzethonium chloride, phenol, etc.

[Inhibitor of active oxygen generation due to ultraviolet rays] Combination of vitamin C and vitamin E, thiotaurine, glutathione, selenium in hot springs, etc.

[Ultraviolet ray-induced wrinkle inhibitor] The aforementioned antioxidants, α-hydroxy acids, vitamin C derivatives, plant extracts, glycine zinc, etc.

[Lipolysis accelerator] Lipolysis extract, caffeine, aminophylline, essential oils such as rosemary, grapefruit, Sphacellaria scoparia extract, etc.

[Firming agents] Ginkgo biloba extract, arnica extract, red grape extract, tea leaf extract, citrus fruit and leaf extract, Ivy extract, meadowsweet extract, lavender extract, etc.

[Irritation reliever] Ceramide, ceramide-like components, ceramide synthesis promoting substances (N-acetylcysteine, nicotinic acid derivatives, yeast extract), etc.

[Anti-inflammatory agents] ε-aminocaproic acid, lysozyme chloride, guaiazulene, glycyrrhetinic acid and its derivatives, licorice extract, chamomile extract, rhododendron extract, perilla extract, sorcery extract, canker extract, peach leaf extract, polyphenol-containing plant extract, etc.

The concentration of the water-compatible functional component in the aqueous solution may be determined as appropriate depending on the use, but it is generally about 5 to 90% by mass, particularly about 10 to 60% by mass.

The degree of affinity for water of a water-friendly functional ingredient is not particularly limited, but when 1 g of the target active ingredient is added to a solution separated into two phases of 50 ml of water and 50 ml of oleic acid at 20°C, It is preferable that 90% or more, preferably 95% or more, and more preferably 99% or more of the functional component be present in water in order to fully exhibit the effectiveness of the functional component.

Furthermore, the amount of the aqueous solution containing the water-compatible functional component supported on the hydrophobized metal oxide airgel powder is usually 10 to 90% by mass, preferably 20 to 90% by mass, and more preferably 50 to 90% by mass. It is 90% by mass. The larger the supported amount is, the more preferable it is since the release amount of water-compatible functional components can be ensured, but if the supported amount exceeds this range, there is a risk that the composite powder will not be able to maintain its powder properties. There is.

The properties of the above powder are measured using a Hosokawa Micron Powder Tester (PT-X) using sieve openings (150, 75, 45 μm from the top), amplitude (1 mm), and vibration time (60 s). It can be expressed as the degree of cohesion. This degree of aggregation is usually 90% or less, preferably 50% or less, and more preferably 20% or less.

Hereinafter, the usage mode of the composite powder of the present invention will be specifically explained using a powder cosmetic as an example, which is a typical usage mode.

When the composite powder of the present invention is used as a component of a powder cosmetic, the amount to be blended may be determined as appropriate depending on the type of powder cosmetic. It is preferably present in a proportion of 5 to 50% by weight, preferably 10 to 30% by weight.

In addition, the composition of the powder cosmetic containing the composite powder of the present invention may be any known composition without particular limitation. For example, in the case of face powder, extender pigments such as talc, kaolin, mica, sericite, barium sulfate, calcium carbonate, silicic anhydride, magnesium silicate, white pigments such as titanium oxide, zinc oxide, red iron oxide, yellow oxide, etc. Generally, the composition is a mixture of appropriately selected colored pigments such as iron, black iron oxide, ultramarine, and navy blue, pearl pigments such as titanium mica and colored titanium mica, and polymers such as polyethylene phthalate, polyethylene, and nylon. In addition, additives such as thickeners and stabilizers such as silica and polymethyl methacrylate, processing agents such as dimethicone, humectants such as collagen and hyaluronic acid, and skin whitening agents such as hydroquinone and tranexamic acid are used. Sometimes it is done.

The composite powder can be blended into the powder cosmetic by dry mixing the powders of the components. In addition, when using a liquid component such as a humectant, it is preferable to mix it with a hydrophobic powder in advance and perform the above-mentioned dry mixing to form a water capsule.

When the powder cosmetic contains a water-friendly functional ingredient such as a humectant free of charge, the water-friendly functional ingredient carried by the composite powder of the present invention may be the same ingredient. However, since each component exists in powder form, there is a low possibility that the aqueous solution supported on the composite powder will come into contact with the above-mentioned water-compatible functional components that are freely blended into the face powder. It is also possible to do so.

The face powder containing the composite powder of the present invention provides a smooth application feeling due to the rolling effect of the spherical composite powder, and its ability to absorb sebum prevents shine at the application site even after a long period of time has passed since application. The aqueous solution of water-friendly functional ingredients, such as moisturizing ingredients, which is released simultaneously with the absorption of sebum while suppressing sebum, provides a sustained skin care effect.

[Method for manufacturing composite powder]
Although the method for producing the composite powder of the present invention is not particularly limited, a hydrophobized metal oxide airgel powder is produced by the following method, and then, or during the production process, an aqueous solution containing a water-philic functional component is prepared. A method of supporting the pores of a hydrophobized metal oxide airgel powder is mentioned.

<Method for producing spherical hydrophobized metal oxide airgel powder>
Although the method for producing the hydrophobized metal oxide airgel powder used in the present invention is not particularly limited, for example, the spherical hydrophobized metal oxide airgel powder can be preferably produced by the method described below.

That is, an O/W/O emulsion or a W/O emulsion having an aqueous metal oxide sol as the W phase (aqueous phase) is formed, and then the metal oxide sol is gelled in the emulsion. It can be produced by extracting the gel into a hydrophobic organic solvent after performing a hydrophobic treatment such as silylation treatment.

The aqueous metal oxide sol may be prepared by appropriately selecting a known method for preparing an aqueous metal oxide sol (hereinafter, the aqueous metal oxide sol will be simply referred to as "metal oxide sol"). As raw materials for producing the metal oxide sol, metal alkoxides; alkali metal salts of metal oxoacids such as alkali metal silicates; various water-soluble metal salts such as water-soluble salts of inorganic acids or organic acids; etc. may be used. Can be done.

Among the raw materials for producing the metal oxide sol described above, alkali metal silicate salts can be suitably used because they are inexpensive, and sodium silicate is more suitable because it is easily available. In the following, a typical example will be explained in which sodium silicate is used as a raw material for producing metal oxide sol, and silica is produced as a metal oxide. However, even when other metal sources are used, known methods can be used to produce aqueous sol By performing the preparation and gelation, the hydrophobized metal oxide airgel powder of the present invention can be obtained in the same manner.

When using an alkali metal silicate such as sodium silicate, neutralization with mineral acids such as hydrochloric acid or ^sulfuric acid, or cation exchange resin (hereinafter referred to as Silica sol can be prepared by substituting alkali metal atoms in an alkali metal silicate salt with hydrogen atoms by a method using an alkali metal silicate.

The concentration of the silica sol prepared by the above method is preferably 50 g/L or more in terms of silica concentration (SiO ₂ equivalent concentration). On the other hand, it is preferably 160 g/L or less, and 100 g/L or less, since the density of the silica particles can be relatively small to obtain a good pore volume and increase oil absorption. It is more preferable.

First, a W/O type emulsion or an O/O emulsion is prepared, in which the aqueous metal oxide sol (here, silica sol) obtained by the above method is used as the W phase (aqueous phase), and the liquid immiscible with water is used as the O phase (organic phase). A W/O emulsion (hereinafter, both may be simply referred to as an emulsion) is formed. As a method for forming the emulsion, a known method can be appropriately selected and carried out. Since the particle size of the dispersed W phase is approximately the particle size of the metal oxide particles, the dispersion strength, dispersion time, and amount of surfactant added can be adjusted to obtain the desired median size. good.

Following the formation of the O/W emulsion, an O/W/O emulsion can also be formed using a solvent (second O phase) that is immiscible with the W phase of the O/W emulsion. Also in this case, it is preferable to further add a surfactant in addition to the solvent.

When forming the above O/W/O type emulsion, the above-described method for forming an O/W type emulsion may be adopted as a method for dispersing the sol in a liquid that is immiscible with water. The particle size of the dispersed metal oxide sol (W phase) is approximately the particle size of the particles constituting the hydrophobized metal oxide airgel powder of the present invention to be produced. Therefore, the dispersion strength, dispersion time, and amount of surfactant added may be adjusted to obtain the desired median particle size. That is, the particle size of the sol is preferably such that the median diameter in the particle size distribution measured by laser diffraction is in the range of 1 to 50 μm, more preferably in the range of 1 to 30 μm. As mentioned above, when the particle size of the W phase is observed under a microscope, it is preferably 1 to 50 μm, particularly 1 to 30 μm.

After forming an emulsion by the above-described operation, the metal oxide sol is gelled. For the gelation, any known gelation method can be used without any particular restriction as long as the state of the emulsion is not disrupted.

An example of a first preferred method is a method in which the pH is adjusted during formation of the metal oxide sol so that it takes a certain amount of time to gel. That is, in the formation of the metal oxide sol described above, gelation does not occur during emulsion formation, and then the pH is adjusted to such a level that gelation occurs by holding the emulsion at a constant temperature for about 30 minutes. Specifically, when performing each operation at room temperature, if the silica concentration is within the above range, the pH is preferably within the range of 2 to 5, and preferably within the range of 2.5 to 4.5. It is more preferable.

A second preferred method is a method of increasing the pH of the W phase to make it weakly acidic or basic by adding a basic substance to the emulsion. In this case, when preparing the metal oxide sol, it is preferable to adjust the pH to a low level (about 0.5 to 2.5) so that the sol is relatively stable. As a specific method for increasing the pH of the W phase, it is preferable to determine in advance the amount of base that will bring the W phase to the desired pH, and to add that amount of base to the emulsion. To determine the amount of base that will give the desired pH, take a certain amount of the metal oxide sol used for the emulsion, measure the pH of the separated metal oxide sol with a pH meter, and add the base used for gelation. This can be done by measuring the amount of base that achieves the desired pH in addition to the fractionated metal oxide sol.

Note that examples of the basic substance include ammonia, caustic soda, and alkali metal silicates.

The time required for the gelation described above depends on the temperature and concentration of the silica sol, but when the pH is 5, the temperature is 50°C, and the silica concentration in the silica sol is 80g/L (SiO ₂ equivalent), the gelation will occur after a few minutes. happens.

Following the above method, an operation is performed to separate the dispersion solvent into two layers, an O phase and a W phase. This operation is generally referred to as defrosting, and the gelled product obtained by the above method is present on the W phase side obtained by separation.

As the W phase separation method, it is possible to adopt a known method, but specifically, addition of a water-soluble organic solvent, addition of a salt, application of centrifugal force, addition of an acid, filtration, volume ratio. (addition of water or a hydrophobic solvent), etc., or a combination of them can be carried out. Preferably, a certain amount of a water-soluble organic solvent is added to the emulsion to separate it into two layers, an O phase and a W phase. After this step, the upper layer generally becomes an O phase (organic layer) and the lower layer becomes a W phase (aqueous layer).

Examples of the water-soluble organic solvent include acetone, methanol, ethanol, isopropyl alcohol, and the like. Among these, isopropyl alcohol can be preferably used in the silylation treatment described below, since it is effective in increasing the efficiency of the treatment.

From the viewpoint of increasing the strength of the particles constituting the hydrophobized metal oxide airgel powder of the present invention, gelation reaction (aging) is carried out for about 0.5 to 24 hours after milking. It is also preferable to allow the dehydration condensation reaction to proceed further. The ripening can be carried out by maintaining the temperature between room temperature and about 80°C.

In order to improve the processing efficiency of the subsequent silylation treatment of the gelled product, the O phase is removed by decantation etc. from the two-layer separated liquid of O phase and W phase obtained in the above operation, and the W phase is can be recovered.

In the present invention, in order to obtain a hydrophobized metal oxide airgel powder, after separating the W phase, the gelled product is silylated using a silylating agent. As the silylating agent to be used, any known silyl agent that reacts with the hydroxyl group present on the surface of the metal oxide (silica in this case) to impart a hydrophobic group to the surface can be used without particular limitation.

Specifically, the above silylating agents include chlorosilanes such as chlorotrimethylsilane, dichlorodimethylsilane, and trichloromethylsilane, alkoxysilanes such as monomethyltrimethoxysilane and monomethyltriethoxysilane, hexamethyldisilazane, and hexamethyl Silazane such as cyclotrisilazane, siloxane such as hexamethylsiloxane, octamethyltrisiloxane, cyclic siloxane such as siloxane octamethylcyclotetrasilazane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, etc. can be mentioned. Among them, chlorotrimethylsilane, dichlorodimethylsilane, trichloromethylsilane, octamethylcyclotetrasiloxane, hexamethyldisilazane, and hexamethyldisiloxane are particularly preferred in terms of good reactivity.

By performing silylation treatment using such a silylation agent, the hydroxyl groups on the surface of the metal oxide are end-capped with hydrophobic silyl groups and inactivated, so that dehydration between surface hydroxyl groups can occur. Condensation reactions can be suppressed. Therefore, drying shrinkage can be suppressed even when drying is performed under conditions below the critical point, so it is possible to obtain a hydrophobized metal oxide airgel powder having a pore volume of 0.5 L/g or more, particularly 2 mL/g or more. It becomes possible.

The amount of treatment agent used in the above silylation treatment depends on the type of treatment agent, but for example, if the metal oxide is silica and dimethyldichlorosilane is used as the treatment agent, the metal oxide (Silica) 30 to 150 parts by weight per 100 parts by weight is suitable.

The conditions for the silylation treatment described above can be carried out by adding a silylation treatment agent to the W phase separated in the demulsification operation and allowing the mixture to react for a certain period of time. For example, when the metal oxide is silica, dimethyldichlorosilane is used as the silylation treatment agent, and the treatment temperature is 50°C, the treatment can be carried out by holding it for about 4 to 12 hours or more. When siloxane is used and the treatment temperature is 70° C., the treatment can be carried out by holding the treatment for about 6 to 12 hours or more.

In addition, when using cyclic siloxanes such as octamethylsiloctetrasiloxane or siloxanes such as hexamethyldisiloxane as the silylation treatment agent, the pH of the solution is adjusted to 0.3 to 1.0 by adding hydrochloric acid. This is preferable in terms of increasing reaction efficiency.

In the silylation treatment step, a water-soluble organic solvent is preferably added for the purpose of increasing the solubility of the treatment agent in the W phase and increasing the efficiency of the reaction. Examples of the water-soluble organic solvent include acetone, methanol, ethanol, isopropyl alcohol, and the like. Among these, isopropyl alcohol can be preferably used.

The water-soluble organic solvent is preferably added so that the concentration in the W phase is approximately 20 to 80% by mass.

After the silylation treatment, the gelled product is extracted into a hydrophobic organic solvent. The criteria for selecting a hydrophobic organic solvent for use in extracting the gelled product is that it should have a low surface tension so as not to cause drying shrinkage during the subsequent drying step. Specifically, hexane, heptane, dichloromethane, methyl ethyl ketone, toluene, etc. can be used, and preferably hexane, heptane, toluene can be used.

After extraction into the hydrophobic organic solvent described above, in order to remove salts contained in the gelled product and sulfates contained in the hydrophobic organic solvent, the organic solvent is diluted with water or an aqueous alcohol solution. It is preferable to perform washing. This washing operation can be performed by a known method. In order to increase the cleaning efficiency, it is preferable to use an aqueous solution of isopropyl alcohol of about several tens of mass %. Further, in order to improve the cleaning efficiency, it is preferable to raise the temperature to a high temperature within a range that does not exceed the boiling point of the hydrophobic organic solvent. Usually, it can be carried out at a temperature in the range of 50 to 70°C.

After performing the gelled product extraction described above, the gel dispersed in the hydrophobic organic solvent is separated from the solvent by filtration or the like, and the hydrophobic organic solvent is removed (ie, dried). The temperature during drying is preferably higher than the boiling point of the solvent and lower than the decomposition temperature of the surface treatment agent, and the pressure is preferably normal pressure to reduced pressure.

By performing the above method, a hydrophobized metal oxide airgel powder can be obtained.

The method for producing the hydrophobized metal oxide airgel powder is described in detail in, for example, JP-A-2014-218433, and the desired hydrophobized metal oxide airgel powder can be produced according to this method. Bye.

In the present invention, there are no particular limitations on the method for supporting an aqueous solution containing a water-affinity functional component on the hydrophobized metal oxide airgel powder obtained by the above method. Typical examples include the following methods.

In one embodiment, the hydrophobized metal oxide airgel powder obtained by the drying treatment is once dispersed in a polar organic solvent such as alcohol, and then filtered to obtain a wet cake. Examples include a method in which the aqueous solution is dispersed in and brought into contact with an aqueous solution containing an affinity functional component, thereby causing the aqueous solution to be supported in the pores, filtered again, and dried if necessary.

In another embodiment, after the silylation treatment in the production method, the hydrophobized metal oxide airgel powder is dispersed in a water-soluble organic solvent without drying, and the water-compatible functional component is contained in the powder. A method may also be adopted in which the aqueous solution containing the water-affinity functional component is supported in the pores of the hydrophobized metal oxide airgel powder by mixing an aqueous solution, followed by filtering and drying.

In yet another embodiment, after the silylation treatment in the production method, the hydrophobized metal oxide airgel powder is dispersed in an organic solvent capable of dissolving the water-compatible functional component without drying,
A water-friendly functional component is mixed and dissolved in this, and the organic solvent containing the water-friendly functional component is permeated into the pores of the hydrophobized metal oxide airgel powder, and then filtered. Dry to obtain a hydrophobized metal oxide airgel powder that supports water-friendly functional components in its pores, and then heat the powder to an appropriate humidity and temperature, specifically, a humidity of 20 to 80%. The composite powder of the present invention can also be obtained by treating the powder at 20 to 40° C. to supply water into the pores to form an aqueous solution.

According to the above method, the absence of water during drying in a series of manufacturing steps effectively prevents the resulting dry powder from sticking, resulting in a powder with high fluidity. Further, since water is also supplied in the form of steam, the fluidity described above is not impaired.

In addition, the physical properties of the hydrophobic metal oxide airgel powder in the above embodiment are such that by dispersing the obtained composite powder in heptane, the supported substances in the pores are extracted into heptane, and then the heptane is removed. By drying, a hydrophobic metal oxide airgel powder is obtained, and the powder can be confirmed by measuring the specific surface area, pore volume, etc. of the powder.

EXAMPLES Hereinafter, Examples will be shown to specifically explain the present invention, but the present invention is not limited only to these Examples. In Examples and Comparative Examples, the electrical conductivity of the washing water was measured using an electrical conductivity meter. Furthermore, the glycerin concentration of the composite powders obtained in Examples and Comparative Examples was measured by gas chromatography after extraction with ethanol. The moisture content of the composite powder was measured by the Karl Fischer method.

<Evaluation method>
The hydrophobized metal oxide airgel powders and composite powders produced in Examples and Comparative Examples were tested for the following items.

(Measurement of average circularity)
Image analysis was performed on SEM images of more than 2000 hydrophobized metal oxide airgel powder particles observed at a magnification of 1000 times using a SEM (S-5500 manufactured by Hitachi High Technologies, acceleration voltage 3.0 kV, secondary electron detection). , the average circularity was calculated according to the definition above.

(Measurement of particle size distribution and median diameter by laser diffraction)
0.3 g of the hydrophobized metal oxide airgel powder was added to 40 ml of ethanol, and dispersed for 5 minutes at an output of 100 W using an ultrasonic cleaner UT-105S manufactured by Sharp Manufacturing Co., Ltd. The above-mentioned dispersion was carried out using a Labouran screw tube bottle with an outer diameter of 35 mmΦ and a capacity of 50 ml, which was placed in a washing tank containing an appropriate amount of water.

The particle size distribution of the dispersion liquid was measured using Microtrac MT3000 manufactured by JGC Instruments Co., Ltd. The refractive index of the solvent was 1.38 and the refractive index of the particles was 1.46. From the obtained particle size distribution, the median diameter with respect to the volume distribution was evaluated.

(Measurement of other physical property values)
The BET specific surface area and BJH pore volume were measured using BELSORP-max manufactured by Bell Japan Co., Ltd. according to the above definitions. The oil absorption was measured by the "refined linseed oil method" specified in JIS K5101-13-1.

(Contact test of composite powder with sebum)
In order to confirm the function of the composite powder, the following tests were conducted using the composite powder obtained in Examples and Comparative Examples.

6 g of oleic acid was added to 3 g of composite powder and mixed thoroughly. By standing for 5 minutes, the mixture was separated into two layers: an oil layer containing oleic acid and the composite powder, and a water layer released from the composite powder. The aqueous layer was collected and weighed. The release rate r was calculated by the ratio to the initial value.
Next, the weight of the oil layer was measured. 1 g of the oil layer was dried at 105° C. for 3 hours, and the concentration of water and water-soluble active ingredients was measured from the weight loss.

(Sensory evaluation of composite powder)
The composite powders obtained in Examples and Comparative Examples were passed through a 75-mesh sieve, and then applied to the faces of 10 testers to evaluate the feeling of use. The ``soft focus effect,'' ``cooling feeling,'' ``no shine,'' and ``moist feeling'' upon application were evaluated.

<Example 1>
Hydrophobized metal oxide airgel powder was manufactured by the following method.
A sodium silicate solution having a concentration of 191 g/L for SiO ₂ and 62 g/L for Na ₂ O was prepared. In addition, sulfuric acid whose concentration was adjusted to 88 g/L was prepared. Sulfuric acid was added to the sodium silicate prepared above to adjust the pH to 3 to prepare a silica sol containing 80 g/L of SiO ₂ . Take 108 g of this silica sol, add 160 ml of heptane, add 1.2 g of sorbitan monooleate, and stir for 2.5 minutes at 9000 rpm using a homogenizer (manufactured by IKA, T25DS1). An O/W emulsion was formed.

The aqueous silica sol was stirred for 1 hour using a stirring blade in a constant temperature bath at 70°C to gelatinize the aqueous silica sol.
40 g of isopropyl alcohol and 60 g of ion-exchanged water were added and stirred with a stirring blade, and at the same time, 2.5 g of 2% sodium hydroxide was added to age the W phase for 2.5 hours. Thereafter, by allowing the mixture to stand still, it was separated into two layers, the O phase as an upper layer and the W phase as a lower layer.

By removing the upper O phase by decantation, the lower W phase was recovered. To the obtained W phase, 30 g of isopropyl alcohol, 45 g of ion-exchanged water, 6 g of hexamethyldisiloxane, and 25 g of 35% hydrochloric acid were added, and the mixture was kept in a water bath at 70° C. for 12 hours or more while stirring to perform silylation. processed. After the above treatment, 18.5 g of 48% sodium hydroxide and 18.5 g of ion-exchanged water were added, and neutralization treatment was performed for 30 minutes while stirring with a stirring blade. The resulting gelled product after silylation was filtered using a suction filter, washed with ion-exchanged water until the conductivity of the filtrate became 100 μs/cm or less, and then filtered. The hydrophobized metal oxide airgel powder of the present invention was obtained by drying the gelled product under normal pressure while flowing nitrogen. The drying temperature and time were 150° C. for 12 hours. 100 g of isopropyl alcohol was added to 10 g of the obtained hydrophobized metal oxide airgel powder to disperse the hydrophobized metal airgel powder, and then filtered. By adding 90 g of ion-exchanged water and 10 g of glycerin to 100 g of the obtained wet cake, an aqueous solution containing glycerin was supported in the pores of the hydrophobized metal oxide airgel powder. The solvent was removed using a rotary evaporator at a temperature of 70°C and a degree of vacuum of 100 hpa or less, resulting in a composite powder containing 23.4% by mass of hydrophobized metal oxide airgel powder, 21.8% by mass of glycerin, and 54.8% by mass of water. I got a body.

Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder and the composite powder obtained by extracting the above composite powder into heptane and then drying the heptane.

In addition, as a result of conducting a release test of an aqueous solution containing a water-friendly functional component on the obtained composite powder, the release rate r = 100%, and the contact with sebum ensures that sebum enters the pores. In addition to the absorption, the aqueous solution containing the water-compatible functional component supported within the pores could be reliably released.

Furthermore, when the above composite powder was applied to the face, it was found to have a smooth feel, a high soft focus effect, no shine after application, and a fresh and moist feeling, giving a good feeling of use. It was done.

<Example 2>
The amount of silylating agent used in the silylation treatment of Example 1 was 4 g, and after the silylation treatment, 18.5 g of 48% sodium hydroxide and 18.5 g of ion-exchanged water were added, and neutralized for 30 minutes while stirring with a stirring blade. processed. Thereafter, in order to remove sulfates and the like, the mixture was washed three times with 100 mL of ion-exchanged water, and then filtered. By adding 5 g of glycerin and 90 g of water to 100 g of the obtained wet cake, an aqueous solution containing glycerin was supported in the pores of the hydrophobized metal oxide airgel powder. The solvent was removed using a rotary evaporator at a temperature of 70°C and a degree of vacuum of 100 hpa or less, resulting in a composite powder containing 58.2% by mass of hydrophobized metal oxide airgel powder, 31.4% by mass of glycerin, and 10.4% by mass of water. I got a body.

Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder and the composite powder obtained by extracting the above composite powder into heptane and then drying the heptane.

In addition, as a result of conducting a release test of an aqueous solution containing a water-friendly functional component on the obtained composite powder, the release rate r = 97%, and the contact with sebum ensures that sebum enters the pores. In addition to the absorption, the aqueous solution containing the water-compatible functional component supported within the pores could be reliably released.

Furthermore, when the above composite powder was applied to the face, it had a high soft focus effect, the skin was moisturized without shine, and the feeling of use was good.

<Example 3>
After the silylation treatment in Example 1, a neutralization treatment was performed, and the wet cake was washed three times with 100 mL of ion-exchanged water to remove sulfates, etc., and 100 g of the wet cake obtained after filtration was added with 10 g of glycerin and water. By adding 90 g, the aqueous solution containing glycerin was supported in the pores of the hydrophobized metal oxide airgel powder. The solvent was removed using a rotary evaporator at a temperature of 70° C. and a vacuum of 70 hpa or less. The obtained powder was treated at a humidity of 60% and a temperature of 20°C to obtain a composite powder containing 40.9% by mass of hydrophobized metal oxide airgel powder, 45.3% by mass of glycerin, and 13.8% by mass of purified water. I got a body.

Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder and the composite powder obtained by extracting the above composite powder into heptane and then drying the heptane.

Regarding the obtained composite powder, a release test of an aqueous solution containing a water-friendly functional component was performed, and the release rate r = 100%, indicating that sebum is reliably absorbed into the pores by contact with sebum. At the same time, it was possible to reliably release the aqueous solution containing the water-friendly functional component supported within the pores.

Furthermore, when the above composite powder was applied to the face, the soft focus effect was high, the skin was moisturized without shine, and the feeling of use was good.

<Example 4>
After adding 70 g of isopropyl alcohol to 10 g of hydrophobized metal oxide airgel powder with an M value of 47 obtained by the method of Example 1, sodium hyaluronate was adjusted to 0.3% by mass using ion-exchanged water in advance. Add 50 g of aqueous solution and remove the solvent using a rotary evaporator at a temperature of 70°C and a degree of vacuum of 100 hpa or less to obtain 23.8% by weight of hydrophobized metal oxide airgel powder, 0.4% by weight of sodium hyaluronate, and purified A composite powder containing 75.8% by mass of water was obtained.

Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder and the composite powder obtained by extracting the obtained composite powder into heptane and drying the heptane.

In addition, as a result of conducting a release test of an aqueous solution containing a water-friendly functional component for the above composite powder, the release rate r = 100%, and the reliable absorption of sebum into the pores due to contact with sebum. At the same time, it was possible to reliably release the aqueous solution containing the water-friendly functional component supported within the pores.

Furthermore, when the above composite powder was applied to the face, it had a high soft focus effect, felt like the release of water-friendly functional ingredients, and left the skin moisturized without being shiny, giving it a good feeling of use. .

<Example 5>
After adding 70 g of isopropyl alcohol to 10 g of hydrophobized metal oxide airgel powder with an M value of 47 obtained by the method of Example 1, the mixture was adjusted to 0.3% by mass using 10 g of glycerin and ion-exchanged water in advance. 50 g of sodium hyaluronate aqueous solution was added, and the solvent was removed using a rotary evaporator at a temperature of 70°C and a degree of vacuum of 68 hpa or less, resulting in 26.3% by mass of hydrophobized metal oxide airgel powder and 21.8% by mass of glycerin. A composite powder containing 0.4% by mass of sodium hyaluronate and 75.8% by mass of purified water was obtained.

Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder and the composite powder obtained by extracting the obtained composite powder into heptane and drying the heptane.

In addition, as a result of conducting a release test of an aqueous solution containing a water-friendly functional component for the above composite powder, the release rate r = 100%, and the reliable absorption of sebum into the pores due to contact with sebum. At the same time, it was possible to reliably release the aqueous solution containing the water-friendly functional component supported within the pores.

Furthermore, when the above composite powder was applied to the face, it had a high soft focus effect, felt like the release of water-compatible functional ingredients, and left the skin moisturized without being shiny, giving it a good feeling of use. .

<Comparative example 1>
Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder with an M value of 62 and the physical properties of the composite powder. This hydrophobized metal oxide airgel powder was unable to support an aqueous solution containing a water-philic functional component within its pores.

<Comparative example 2>
Table 1 shows the physical properties of the hydrophobized metal oxide airgel powder with an M value of 15 and the physical properties of the composite powder. As a result of conducting a contact test of the composite powder with sebum, the release rate r was 5%, and the release of the water-compatible functional component was extremely small.

When the obtained composite powder was applied to the face, it felt sticky and heavy and did not suppress shine. In addition, there was no moist feeling after application, and the effect of releasing water-compatible functional ingredients with absorption of sebum could not be obtained.

<Comparative example 3>
Table 2 shows the physical properties of the hydrophobized metal oxide airgel powder with an M value of 0 and the physical properties of the composite powder. As a result of conducting a contact test of the obtained composite powder with sebum, the release rate r=0%, and no water-compatible functional component was released by contact with sebum.

Furthermore, when the obtained composite powder with an M value of 0 was applied to the face, it did not suppress stickiness and shine. In addition, there was no moist feeling after application, and the effect of releasing water-compatible functional ingredients with absorption of sebum could not be obtained.

Claims (7)

A composite characterized in that a water-philic functional component is supported in the form of an aqueous solution in the pores of a hydrophobized metal oxide airgel powder having an average particle diameter of 1 to 30 μm and an M value of 20 to 60. powder. 2. The hydrophobized metal oxide airgel powder has a pore volume of 0.5 to 8 ml/g, a peak pore radius of 10 to 40 nm, and a specific surface area of 350 to 1000 m ² /g. composite powder. The composite powder according to claim 1 or 2, wherein the metal oxide is silica. The composite powder according to any one of claims 1 to 3, wherein the hydrophobized metal oxide airgel powder has a spherical shape with an average circularity of 0.8 or more. The composite powder according to any one of claims 1 to 4, wherein the amount of the hydrophobized metal oxide airgel powder supported in the pores is 10% by volume or more of the total pore volume. A powder cosmetic comprising the composite powder according to any one of claims 1 to 5. The powder cosmetic according to claim 6, wherein the water-friendly functional ingredient is a humectant.