JPH11222421A - Ultraviolet light shielding agent and its production, and cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet light shielding agent excellent in safety and having high transparency. SOLUTION: This ultraviolet shielding agent is inorganic powder having ultraviolet light absorbing functional groups on its surface and is obtained by combining inorganic powder having transparency (e.g. silica gel) with a silane coupling agent which is combinable with the inorganic powder and has a reactive functional group able to react with a ultraviolet light absorbing compound [e.g. N-(2-aminoethyl)3-aminopropylmethyl dimethoxysilane] and then by reacting the reactive functional group of the silane coupling agent with a UV light absorbing compound such as p-methoxycinnamate chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet protective agent, a method for producing the ultraviolet protective agent, and a cosmetic. Specifically, the present invention relates to a novel ultraviolet protective agent suitably used for cosmetics such as sunscreen agents, a method for producing the ultraviolet protective agent, and a cosmetic containing the ultraviolet protective agent.

[0002]

2. Description of the Related Art It is known that human skin is variously affected by irradiation of ultraviolet rays. Normally, most of the ultraviolet rays that humans receive are derived from sunlight. The ultraviolet rays (UV) contained in the sunlight rays are classified according to their wavelengths.
-B, short wavelength ultraviolet light (280 nm or less) is called UV-C. Among them, most of UV-C is absorbed by ozone in the atmosphere and does not reach the surface of the earth. UV-B also causes acute inflammation (erythema,
erythema) and burns (sunbern) causing the UV
-A has high permeability to the skin and causes changes in elastic fibers, collagen and hyaluronic acid in the dermis, and it is thought that these changes lead to promotion of skin aging.
In addition, the skin receives ultraviolet rays to promote the production of melanin, and excessive ultraviolet rays promotes the deposition of spots. Therefore, it is important to protect the skin from UV radiation in order to prevent accelerated aging of the skin and to prevent the occurrence and deterioration of spots and freckles. Here, as a method of protecting the skin from ultraviolet rays, there are a method of applying an ultraviolet protective agent and a method of removing active oxygen generated by irradiating the skin with ultraviolet rays. At present, application of the UV protective agent to the skin is considered to be the simplest and most effective.

[0003] The ultraviolet ray protective agent mainly includes an ultraviolet ray absorbent for absorbing the irradiated ultraviolet ray and an ultraviolet ray reflector for reflecting the irradiated ultraviolet ray. As known UV absorbers, for example, cinnamic acid derivatives, aminobenzoic acid derivatives, salicylic acid derivatives, benzophenone derivatives, urocanic acid derivatives and the like are known. It may be absorbed by the skin and is not very safe. In addition, inorganic powders such as titanium oxide and zinc oxide, which have a scattering effect of ultraviolet rays, are used as the ultraviolet reflector, and these are less likely to be percutaneously absorbed, and are preferable from the viewpoint of safety. is there.

However, the use of such inorganic powders such as titanium oxide and zinc oxide has been considerably limited because of their low transparency (transparency).

In recent years, various methods have been devised to increase the transparency while maintaining the effect on ultraviolet rays by making these inorganic powders finer and surface-treating them, but they have not been sufficient.

The present invention has been made in view of the above-mentioned drawbacks of the conventional examples, and has as its object to provide an ultraviolet protective agent which is excellent in safety and has high transparency.

The inventors of the present application have conducted intensive studies to solve the above-mentioned problems, and as a result, they have completed the present invention by introducing a functional group having an ultraviolet absorbing ability into inorganic powder such as silica gel having high transparency. Reached.

[0008]

The ultraviolet protective agent according to the present invention is characterized in that the surface of the inorganic powder has an ultraviolet absorbing functional group. More specifically, it is characterized in that an ultraviolet absorbing functional group having an ultraviolet absorbing ability is bonded to the surface of the inorganic powder via a silane coupling agent.

Here, the term "ultraviolet absorbing functional group" means a group of functional atomic groups having an absorption spectrum in the ultraviolet region, such as an alkyl residue or a carboxylic acid residue of an ultraviolet absorbing compound widely used as an ultraviolet absorbent. It means a general term for alcohol residues, amino residues, acyl groups and the like. The residue means a compound obtained by removing a hydrogen atom from a carboxyl group, a hydroxyl group, an amino group, or the like in a compound. That is, in the present invention, the ultraviolet-absorbing functional group broadly means a carboxyl group or a hydroxyl group in the ultraviolet-absorbing compound, an atomic group obtained by removing a hydrogen atom from an amino group, an acyl group in the ultraviolet-absorbing compound, or the like. Shall be.

The ultraviolet absorbing compounds used in the present invention include, for example, p-methoxycinnamic acid, p-methoxycinnamic acid,
-Aminobenzoic acid, p-dimethylaminobenzoic acid, salicylic acid and the like. Examples of those having an absorption spectrum in the UV-A region include p-dimethylaminocinnamic acid. Furthermore, in addition to these, various conventionally known ultraviolet absorbing compounds, such as carboxylic acids such as cinnamic acid and gentisic acid, and gallic acid, and alcohols such as cinnamic alcohol, can be mentioned. For example, carboxylic acid residues or alcohol residues of these compounds can be used.

These UV-absorbing functional groups are bonded to the surface of the inorganic powder through a silane coupling agent as described below. It is not particularly limited as long as it has a functional group having a certain property. Also,
If the UV absorbing compound to be bonded is not reactive or is small, it may increase the reactivity, for example, a carboxylic acid halogen compound or an alkyl halide, as described below, or A reactive functional group such as a carboxyl group or an amino group may be introduced into the compound.

The inorganic powder can be applied to those used in ordinary cosmetics. Inorganic powder capable of reacting with a silane coupling agent, specifically, as described below. An inorganic powder having on its surface a functional group capable of reacting with the silane coupling agent, particularly a hydroxyl group, is preferred.
For example, silica gel, kaolin, talc, sericite,
Tricalcium phosphate and the like can be mentioned.

Among these inorganic powders, inorganic powders having high transparency are preferably used so as to be widely applicable as sunscreen cosmetics. Among them, silica gel is particularly preferably used because it is easy to introduce a silane coupling agent, is highly transparent, and can be obtained at low cost. Furthermore, from the viewpoints of the feeling of use of the cosmetic and the ability to protect against ultraviolet rays, the smaller the particle size, the more preferable the particle size is 10 μm or less, more specifically, 0.01 to 10 μm. Preferably, silica gel is used.

In the present invention, the silane coupling agent is a silane derivative, which means a compound having a reactive functional group which is reactive with the above-mentioned ultraviolet absorbing compound, especially a hydroxyl group on the surface of the above-mentioned inorganic powder. Is highly reactive with
For example, a silane derivative containing an alkoxyl group such as a methoxy group or an ethoxy group that generates a Si-OH group by hydrolysis or the like, or a silane derivative containing a Si-Cl group is preferably used. Further, it is appropriately selected according to the ultraviolet absorbing functional group (or ultraviolet absorbing compound) to be bonded.

More specifically, the alkoxyl group-containing silane derivatives include those having a vinyl functional group as a reactive functional group, and those having an amino functional group such as vinyl methoxy silane and vinyl ethoxy silane. , Aminopropylsilane, aminopropyltriethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl)
Examples of 3-aminopropyltrimethoxysilane and the like having an epoxy functional group include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyldimethoxysilane, and those having a chloro functional group.
-Chloropropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropylmethoxysilane having a mercapto-type functional group are exemplified. Examples of the Si-Cl group-containing silane derivative having a vinyl-based functional group include 5-hexenyltrichlorosilane and vinyltrichlorosilane. Of course, the present invention is not limited to these cyan coupling agents as long as they can be combined with the inorganic powder.

The ultraviolet protective agent according to the present invention can be easily prepared by the following method. First, the silane coupling agent is bonded to the inorganic powder by a conventional method. For example,
While stirring the inorganic powder in various mixers such as a Henschel mixer or a V blender, a solution obtained by diluting the silane coupling agent directly or with an aqueous or non-aqueous solvent,
Addition into a mixer (dry method), or dispersion of an inorganic powder in an aqueous or non-aqueous solvent to form a slurry, and diluting the silane coupling agent directly or with an aqueous or non-aqueous solvent Method (wet method), or inorganic powder heated to a high temperature in a furnace,
The silane coupling agent is bound by a spray method of spraying a solution obtained by diluting the silane coupling agent directly or with an aqueous or non-aqueous solvent.

Next, the silane coupling agent is bonded to the ultraviolet absorbing functional group. As this method, a reactive functional group of the ultraviolet absorbing functional group, that is, a hydroxyl group or a carboxyl group in the ultraviolet absorbing functional group, a vinyl group or an amino group, an epoxy group, a chloro group in a silane coupling agent. Groups, mercapto groups, hydroxyl groups and the like are reacted by a conventional method.

For example, a carboxylic acid compound having the above-mentioned ultraviolet absorbing functional group (p-methoxycinnamic acid, p-aminobenzoic acid, p-dimethylaminobenzoic acid, salicylic acid, etc.) and an amino group in the silane coupling agent To form an acid amide bond, a thioester bond, or an ester bond. Alternatively, an alcohol compound having an ultraviolet absorbing functional group (such as cinnamon alcohol) is reacted with an epoxy group in the silane coupling agent to form an oxyether bond, thereby obtaining a desired ultraviolet protective agent. be able to. At this time, when the reactivity of the ultraviolet absorbing compound is weak as described above, the ultraviolet absorbing compound is converted to a highly reactive compound such as a carboxylic acid halogen or an alkoxide, and then reacted with a silane coupling agent. You may.

The ultraviolet protective agent thus obtained is
In addition to having excellent ultraviolet absorbing ability, it has little absorption from the skin due to the binding of inorganic powder, and can be applied to various sunscreen cosmetics.

[0020]

Next, an ultraviolet protective agent according to the present invention was actually prepared, and the effect of the present invention was confirmed. The present invention is not limited to the following embodiments. (Example) Silica gel ("SYLYS") was used as the inorganic powder.
IA350 ", manufactured by Fuji Silysia Chemical Ltd., average particle size 1.8
μm), silica gel (“BW300”, manufactured by Fuji Silysia Chemical Ltd., average particle size: 60 μm), silica gel (“Ezile 200”, manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.012)
μm), trisodium phosphate (manufactured by Wako Pure Chemical Industries, Ltd.), kaolin (“Kaolin KF”, manufactured by Hori Clay Co., Ltd.), sericite (“Serisite GMS-C”, manufactured by Kinseimatic Co., Ltd.), talc (“Talc MS” ", Manufactured by Nippon Talc Co., Ltd.) to obtain an ultraviolet protective agent according to the present invention as follows.

To 50 g of each of the above inorganic powders, 800 benzene
Then, azeotropic distillation was performed to remove water. Thereafter, 800 ml of benzene and 22.5 ml of aminopropyltriethoxysilane (trade name “S330”, manufactured by Chisso) were added to 40 g of the inorganic powder from which bemben was removed under reduced pressure, and the mixture was refluxed for 24 hours. The reaction product was washed with benzene, ethanol, water, and ethanol in that order to obtain an inorganic powder having a silane coupling agent bonded to the surface.

Next, benzene was added to 20 g of the inorganic powder to which the silane coupling agent had been bound, 16 g of p-methoxycinnamic acid chloride and 12 ml of triethylamine were added, and the mixture was refluxed for 24 hours. Thereafter, the reaction product was washed with benzene and ethanol in that order, and dried under reduced pressure to obtain various p-methoxycinnamic acid-aminopropyltriethoxysilane-inorganic powder compounds of Examples.

[Elemental Analysis] Elemental analysis was performed on various p-methoxycinnamic acid-aminopropyltriethoxysilane-inorganic powder compounds obtained in Examples. Table 1 shows the results.

[0024]

[Table 1]

[Measurement of UV Absorbing Capacity and Transparency]
In order to confirm the effects of the present invention, the ultraviolet absorption capacity and the transparency were measured. For the measurement, a p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound using "Ezile 200" as the silica gel in the examples was used. As comparative examples, untreated silica gel “Ezile 200” and untreated fine particle titanium oxide were used.

The p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound, untreated silica gel and titanium oxide were each used as a base in castor oil at a concentration of 5% w / w (however, 1% w / w for titanium oxide).
%) And uniformly dispersed in a mortar. Each of these samples 2
After applying 5 mg each on a quartz plate, it was sandwiched between different quartz plates to produce a circular thin film having a diameter of about 2 cm. This was measured for transmittance (transmittance) at 240 to 600 nm using a spectrophotometer. The result is shown in FIG. Table 2 shows the average transparency at 400 to 600 nm (calculated from the transmittance area in FIG. 1).

[0027]

[Table 2]

As can be seen from FIG. 1, in the embodiment according to the present invention, the UV-B region (320 nm to 280 nm) is used.
In m), the ultraviolet absorptivity was reduced, and the ultraviolet absorptivity by p-methoxycinnamic acid was confirmed. Also, 40
The average transparency at 0 to 600 nm was 95% or more, and the transparency was also excellent.

[Safety Test] Next, a primary skin irritation test and a cumulative skin irritation test were conducted for the safety of the ultraviolet protective agent according to the present invention.

One 4-week-old male Hartley guinea pig was
Preliminary breeding was performed for a week, and those with good general conditions were subjected to the test. One group consists of 5 animals, room temperature 22 ± 2 ° C, humidity 60 ±
The breeding conditions were 10%. In the test, a p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound using "SYLYSIA350" as a silica gel in the examples was used, and p-methoxycinnamic acid and octyl p-methoxycinnamate were used as comparative examples. Was.

The p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound, p-methoxycinnamic acid, and octyl p-methoxycinnamate were each converted into p-methoxycinnamic acid using white petrolatum as a base. It was adjusted to be 0.3M.

In the primary skin irritation test, the flank of a guinea pig was shaved and 0.1 g of each sample was closed and peeled off using a patch test bandage for 24 hours. Observations were made for days.

In the skin cumulative irritation test, the guinea pigs were shaved on the flanks and 0.1 g each of the guinea pigs was applied once a day using a patch for patch test for 24 hours, followed by continuous administration for 4 days. The observation was performed every 24 hours.

The evaluation was performed according to the Draze evaluation method, and then evaluated according to criteria. Table 3 shows the results of the primary skin irritation test and Table 4 shows the results of the cumulative skin irritation test. The table shows the average evaluation of one group.

(Erythema formation) 0 no erythema 1 rash with scattered redness 1 2 very erythema mildly 3 erythema with clear borders 4 erythema with moderate to strong intensity 4 erythema Erythema 5 points

(Edema formation) ・ No edema 0 points ・ Very mild edema 1 point ・ Mild edema 2 points ・ Moderate edema 3 points ・ Strong edema 4 points

[0037]

[Table 3]

[0038]

[Table 4]

As can be seen from Tables 3 and 4, neither erythema formation nor edema formation was observed in the skin primary irritation test applied for 24 hours and in the skin cumulative irritation test administered continuously for 4 days. No irritation was observed.

Next, in the examples obtained above, the cosmetic (sunscreen) according to the present invention was prepared by using p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound using "SYLYSIA350" as silica gel. Cosmetics).

(Prescription Example 1) Sunscreen cream (W / O type) <Composition> (% by weight) p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound 10.0 p-octyl octyl methoxycinnamate 2.0 squalane 36.0 Microcrystalline wax 1.0 Glycerin diisostearate 3.0 1,3-butylene glycol 4.0 Glycerin 5.0 Preservative / antioxidant qs Perfume qs Purified water balance

Of the above components, five components from a p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound to glycerin diisostearate, and a preservative and antioxidant were mixed and dissolved by heating to form an oil phase.
Separately, an aqueous phase obtained by heating and dissolving 1,3-butylene glycol and glycerin in purified water was added to the oil phase and emulsified. Thereafter, the mixture was cooled with stirring, and a flavor was added to obtain a cream.

(Formulation Example 2) Sunscreen oil <Composition> (% by weight) p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound 10.0 squalane 60.0 cetyl octanoate 29.8 antioxidant Amount Perfume Appropriate amount

The above components were mixed and dissolved by heating to obtain an oil.

(Formulation Example 3) Sunscreen emulsion <Composition> (% by weight) p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound 10.0 squalane 8.0 petrolatum 2.0 beeswax 0.5 sorbitan sesquiole Eat 0.8 Polyoxyethylene oleyl ether (20EO) 1.2 Carboxyvinyl polymer 0.2 Propylene glycol 0.5 Potassium hydroxide 0.1 Ethyl alcohol 7.0 Preservative / antioxidant Appropriate amount Perfume Appropriate Volume Purified water balance

Of the above components, six components from p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound to polyoxyethylene oleyl ether and a preservative / antioxidant are mixed, heated and dissolved, and mixed with an oil phase. did. Separately, an aqueous phase obtained by heating and dissolving a carboxyvinyl polymer, propylene glycol and alcohol in purified water was added to the oil phase and emulsified. Thereafter, potassium hydroxide was added to increase the viscosity, and the mixture was cooled with stirring, and a flavor was added to obtain an emulsion.

(Formulation Example 4) Powder-like sunscreen agent <Composition> (% by weight) p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound 15.0 talc 15.0 mica 20.0 sericite 40.0 Methylpolysiloxane 5.0 Squalane 3.0 Glyceryl tri-2-ethylhexanoate 2.5 Preservative / antioxidant Suitable amount Color pigment Suitable amount

After mixing the four components of sericite and the color pigment from the p-methoxycinnamic acid-aminopropyltriethoxysilane-silica gel compound among the above components, methyl polysiloxane, squalane and tri-2-ethyl were mixed with stirring. A solution obtained by heating and dissolving glyceryl hexanoate and a preservative / antioxidant was added and mixed to obtain a powder.

[0049]

According to the present invention, since the surface of the inorganic powder has an ultraviolet absorbing functional group, its transdermal absorption is low,
It is possible to provide an ultraviolet ray protective agent having the same ultraviolet ray absorbency as a conventional ultraviolet ray absorbent. In particular, by applying to a transparent inorganic powder such as silica gel, an ultraviolet protective agent having high transparency can be provided.

Further, by using a silane coupling agent, it can be easily introduced into the surface of the inorganic powder,
Moreover, because of its low transdermal absorbability, various UV-absorbing functional groups can be introduced, and a wide range of UV protective agents according to the characteristics of cosmetics can be provided.

By using such an ultraviolet ray protective agent in cosmetics, it is possible to provide sunscreen cosmetics having excellent safety and various ultraviolet ray protective properties.

[Brief description of the drawings]

FIG. 1 is a light transmission spectrum of an ultraviolet protective agent according to one embodiment of the present invention.

Claims (8)

[Claims] 1. An ultraviolet protective agent comprising an inorganic powder having an ultraviolet absorbing functional group on the surface. 2. The ultraviolet protective agent according to claim 1, wherein the ultraviolet absorbing functional group is bonded via a silane coupling agent surface-treated to the inorganic powder. 3. The ultraviolet protective agent according to claim 1, wherein the inorganic powder has a hydroxyl group on the surface. 4. The ultraviolet protective agent according to claim 1, wherein the inorganic powder has a light transmitting property. 5. The ultraviolet protective agent according to claim 1, wherein the inorganic powder is silica gel. 6. The ultraviolet protective agent according to claim 5, wherein the particle size of the silica gel is 10 μm or less. 7. The method for producing an ultraviolet ray protective agent according to claim 1, wherein the reactive functional group capable of binding to the inorganic powder and reacting with the ultraviolet absorbing compound is provided on the surface of the inorganic powder. A method for producing an ultraviolet protection agent, comprising: bonding a silane coupling agent having a group; and reacting the silane coupling agent bonded to the inorganic powder with an ultraviolet absorbing compound. 8. A cosmetic comprising the ultraviolet protective agent according to claim 1, 2, 3, 4, 5, or 6.