JP2578037B2 - Water-in-oil emulsion cosmetics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has good adhesion to the skin,
The present invention relates to a cosmetic having a good finish, a feeling of use, and an ultraviolet absorbing ability with excellent durability.

[0002]

2. Description of the Related Art In recent years, it has been clarified that ultraviolet rays cause various skin diseases such as spots and freckles, and as a result, awareness of protecting the skin from ultraviolet rays has increased and various types of ultraviolet ray protective substances have been developed. Is being developed.

Ultraviolet rays that can pass through the ozone layer and reach the human body or the surface of the earth include UV-A (320 to 400 nm) and U-
V-B (290-320 nm), but UV-B has attracted attention because it caused an acute inflammatory reaction before, and mainly UV-B
Various cosmetics and the like for protecting -B have been developed.

However, recent studies have shown that UV-
A has lower energy than UV-B and does not immediately recognize the skin reaction, but it has been found that A accumulates inside the skin and causes skin aging. Therefore, it is necessary to protect UV-A on a daily basis.
Development of UV-A protective substances is underway.

Conventionally, as a UV-A protective substance, fine zinc oxide having an average particle diameter of 0.07 to 0.3 μm has been used because it is effective. It was lacking in feeling. On the other hand, the average particle diameter is 0.1 to 1 μm, and the average thickness is 0.01 to 0.2 μm.
It has been disclosed that a cosmetic containing flaky zinc oxide having an average plate-like ratio of 3 or more does not have such a drawback, has spreadability, has less squeaky feeling, and provides a natural finish (Japanese Patent Application Laid-Open No. Hei 1 (1994)). 175921).

[0006]

However, cosmetics containing this flaky zinc have not been satisfactory with respect to the durability of the ultraviolet ray preventing effect and the stability of the cosmetics. Therefore, an object of the present invention is to provide a cosmetic that is excellent in finish and feeling of use and has a long-lasting effect of preventing ultraviolet rays.

[0007]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive studies, and as a result, a water-in-oil emulsion cosmetic containing specific flaky zinc oxide, ether-modified silicone and silicone oil has been developed. The present invention was found to be excellent in finish, feeling of use, and durability, and completed the present invention.

That is, the present invention provides the following component (A):
(B) and (C) (A) Average particle diameter 0.1-1 μm, average particle thickness 0.0
It is intended to provide a water-in-oil type emulsified cosmetic containing 1 to 0.2 μm and a flaky zinc oxide (B) ether-modified silicone (C) silicone oil having an average plate-like ratio of 3 or more.

In the present specification, the average particle diameter, average particle thickness, and average plate ratio are values measured by the method described in Examples described later. The flaky zinc oxide as the component (A) used in the present invention is described in JP-A-1-175921, and can be produced, for example, by the following method. That is, in producing zinc oxide directly from an aqueous solution containing a salt of zinc, a) containing zinc ions, and b) adding one or more acid groups in an amount exceeding a total equivalent to the zinc ions. C) a method of producing a precipitate from a mother liquor having a pH of 11 or more. In such a method, when reacting zinc ions with an alkaline solution, it is preferable to carry out a mixing reaction at a reaction temperature of 60 ° C. or lower, preferably 40 ° C. or lower, under strong stirring within a short time. Examples of coexisting acid groups include, for example, NO ₃ ⁻ , SO
^{_{4 2-, CH 3 COO -,}} Cl -, PO 4 3-, CO 3 2-, C 2 O 4
One or two or more of ^{2- and the} like can be mentioned. It is necessary that these acid groups are present in the mother liquor in an amount exceeding the equivalent to zinc ions and the pH is 11 or more. Particularly, the pH is preferably 12 or more. Further, after the precipitation, the white slurry is heated to 60 to 100 ° C., preferably 90 to 100 ° C.
By heating to a temperature of 0 ° C. and maintaining the temperature for 10 minutes or more, preferably 30 minutes or more, flaky zinc oxide having better crystallinity can be obtained.

In the above method, when the amount of the acid group with respect to the zinc ion is equal to or less than the equivalent, flaky zinc oxide having a solidified crystal as a main component is easily obtained, and the desired flaky particles are obtained. Control becomes extremely difficult, which is not preferable. There is no particular upper limit on the amount of acid groups. However, if the amount is too large with respect to zinc ions, it takes time and effort for washing during isolation, which is not practical. Depending on the type of acid group ion,
When 1.05 to 2 equivalents are used with respect to zinc ions, preferable results are easily produced. Further, if the pH is less than 11, zinc hydroxide is produced, or the shape becomes granular to rice granular,
In such a pH range, the flaky zinc oxide used in the present invention cannot be obtained.

In the above method, the reaction temperature is 60
If the temperature is higher than 0 ° C, flaky crystals cannot be obtained even if the pH is 11 or more, and spherical or bulk crystals become the main component, which is not preferable.
However, when a white slurry of flaky crystals obtained by a reaction having a reaction temperature lower than 60 ° C. is heated to 60 ° C. or higher, it is necessary to improve the crystallinity while maintaining this shape by powder X-ray diffraction. It was confirmed by the measurement results. In the case of further isolation as a powder, filtration and washing are performed. By performing washing with a water-soluble organic solvent as a final step, subsequent drying and pulverization operations are facilitated. This is particularly effective when it is desired to increase the bulk specific volume.

In the above-mentioned method, an acid group portion exceeding an equivalent amount to zinc ions may be added as a salt or an acid in a zinc salt solution or in an alkaline solution. In the case of salt, any water-soluble salt may be used, specifically, sodium sulfate,
Sodium nitrate, sodium chloride, sodium acetate, potassium sulfate, sodium phosphate, sodium oxalate, sodium carbonate and the like can be used. Further, as the alkali, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide and the like can be used. As a method of adding the aqueous zinc salt solution and the alkali, the alkali may be injected or dropped into the zinc salt, or vice versa, or both may be simultaneously injected and dropped into water or a salt solution.

It has been confirmed that the flaky zinc oxide obtained as described above exhibits crystallinity in powder X-ray diffraction.
Due to the particle morphology, this material has a very large bulk specific volume, and a surprising bulk specific volume several times to ten and several times that of general vapor-phase zinc oxide is possible. In addition, according to the UV spectrum measurement, the obtained flaky zinc oxide has a larger ultraviolet absorbing ability than the commercially available zinc oxide, and a smaller visible light absorption is obtained. Some behavior was exhibited.

The flaky zinc oxide used in the present invention can be used as it is in cosmetics, but if necessary, it can be subjected to a water-repellent treatment such as a silicon treatment.

The ether-modified silicone of the component (B) is not particularly limited as long as it is a compound in which at least a part of the organopolysiloxane is substituted with a group having an ether bond, and the following polyether-modified silicone of the following (1): (2) Polyether / alkyl-modified silicone, (3) alkyl glyceryl ether-modified silicone and the like can be used.

(1) Polyether-modified silicone represented by the following general formula (1)

[0017]

Embedded image

Of these, the molecular weight is 2,000 to 50,000.
And the proportion occupied by R ^{1 to} R ³ is 5 to 40 of the molecular weight.
% Is preferred. Further, in the above general formula (1), m
50 to 80, n is 0 to 2, a is 9 to 10, b is 0, p
Is 3, R ⁴ is a hydrogen atom, or m is 90 to 11
It is particularly preferable to use those in which 0, n is 0, a is 11 to 13, b is 0, p is 3, and R ⁴ is a hydrogen atom.

(2) Polyether / alkyl-modified silicone Here, the polyether / alkyl-modified silicone is:
A modified silicone having a polyoxyalkylene group and a hydrocarbon group having 6 to 16 carbon atoms in the molecule, for example, represented by the following formula (2), and its production method is described, for example, in JP-B-63-36620. It is described in.

[0020]

Embedded image

[Wherein, R^FiveIs a hydrocarbon group having 1 to 5 carbon atoms
And R⁶Represents a hydrocarbon group having 6 to 16 carbon atoms;
Represents an alkylene group;⁷Is the group-(OC_TwoH_Four)_q− (O
C_ThreeH₆) _r-OR⁸(R⁸Is a hydrogen atom or a lower alkyl group
Where q and r are q ≦ r, and-(OC_TwoH_Four)_q−
(OC_ThreeH₆)_rThe number at which the molecular weight of-is 600 to 3500
, Z represents a number of 1 to 3, and x and y represent
x <3y and x + y + z = 30 to 400
Show. However,-(OC_TwoH_Four)_q− (OC_ThreeH₆)_r− Total weight
The amount is 1% of the total weight of the polyether-alkyl-modified silicone.
/ 3)

In the formula (2), which represents one example of the above polyether / alkyl-modified silicone, the hydrocarbon group having 1 to ⁵ carbon atoms represented by R ⁵ is an alkyl or alkenyl group such as a methyl group, an ethyl group, an isopropyl group, Examples thereof include a butyl group, a pentyl group, and a vinyl group, and among them, a methyl group is particularly preferable. In the formula (2), R ⁶ has 6 to 6 carbon atoms.
Preferred as the 16 hydrocarbon groups are, for example, hexyl group, peptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tetradecyl group, linear alkyl group such as hexadecyl group, isooctyl group, s
Examples include a branched-chain alkyl group such as an ec-octyl group and a 2-ethylhexyl group, and among them, a dodecyl group is particularly preferable. In the present invention, when y> 1, each R ⁶ may be the same group or a combination of two or more different groups. (2) In the formula, examples of the alkylene group for Q include a methylene group, an ethylene group, a propylene group, a trimethylene group, a butylene group and the like, and among them, a propylene group and a trimethylene group are particularly preferable.
(2) In the formula, R ⁷ is a group — (OC ₂ H ₄ ) _q — (OC ₃ H ₆ ) _r
-OR ⁸ is indicated. Here, R ⁸ includes a hydrogen atom or a lower alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group, and among them, a hydrogen atom is particularly preferable. Further, q and r satisfy q ≧ r, and the molecular weight of-(OC ₂ H ₄ ) _q- (OC ₃ H ₆ ) _r- is 600.
Although the numbers are と 3500, q and r in the present invention are shown.
Particularly preferable examples of the value of q are q = 15 and r = 0; q
= R = 18; q = r = 25; or q = 29 and r = 7
Is mentioned. In the formula (2), z represents a number of 1 to 3, x and y satisfy x <3y, and x + y + z = 30.
The number is from 0 to 400, x is preferably from 0 to 100, particularly preferably 0, y is preferably a number such that y + z = 30 to 70, and z is preferably 2 or more.

In the present invention, finally,-(OC _{2
H 4) q - (OC 3} H 6) r - total weight of should not exceed 1/3 of the total weight of the polyether alkyl-modified silicone (2).

As the polyether-alkyl-modified silicone (2), commercially available ones can be used, and specific examples thereof include “DC Q2- sold by Dow Corning Toray Silicone Co., Ltd. 520
0 "(lauryl methicone copolyol; R ^{5 in} formula (2)
= CH ₃ , R ⁶ = C ₁₂ H ₂₅ , x = 0), Glen
n) ABIL B98 sold by the company
06 "(cetyl dimethicone copolyol; R in the formula (2)
⁵ = CH ₃ , R ⁶ = C ₁₆ H ₃₃ , x = 0).

(3) Alkyl glyceryl ether-modified silicone As the alkyl glyceryl ether-modified silicone,
At least one of the side chains of the organopolysiloxane is -A
—OCH ₂ CH (OR ⁹ ) CH ₂ OR ¹⁰ (where A represents a divalent hydrocarbon group having 3 to 20 carbon atoms, and R ⁹ and R ¹⁰ represent a hydrogen atom or a hydrocarbon having 1 to 5 carbon atoms, respectively) And at least one of them is a hydrogen atom.).

The silicone oil (C) used in the present invention is not particularly limited, and any silicone oil conventionally used in cosmetics can be used. Specific examples include methylpolysiloxane; methylphenylpolysiloxane; dimethylcyclopolysiloxane such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane.

The amount of the components (A) to (C) used in the cosmetic of the present invention is not particularly limited, but is usually 0.1%.
1 to 20 parts by weight, preferably 1 to 20 parts by weight,
Component (B) is 0.2 to 20 parts by weight, preferably 1 to 10 parts by weight.
5 parts by weight, preferably 5 to 80 parts by weight, preferably 10 parts by weight
６０60 parts by weight. In addition, each component may be used alone or in combination of two or more.

The cosmetic of the present invention may contain water, a known ultraviolet absorber, an oily base other than silicone oil, alcohols, and a surfactant in addition to the above essential components, as long as the effects of the present invention are not impaired. , Viscosity modifiers, stabilizers, wetting agents,
Moisturizers, preservatives, pH adjusters, antioxidants, thickeners, powders, pigments, fragrances, medicinal ingredients and the like can be appropriately compounded.

The oily bases other than the silicone oil include hydrocarbon groups such as squalane, liquid paraffin and petrolatum; waxes such as spermaceti and carnauba wax; jojoba oil; octyldodecyl myristate; neopentyl glycol dioctanoate. Ester oils; natural animal and vegetable oils and fats such as olive oil and macadamia nut oil; diglycerides and the like.

The method of preparing the water-in-oil emulsion cosmetic of the present invention is not particularly limited, but the components (A) to (C) and the aqueous phase component may be mixed and stirred in a conventional manner. The form of the cosmetic of the present invention is not particularly limited, but is preferably a milky lotion, a cream, a foundation or the like.

[0031]

The water-in-oil type emulsified cosmetic of the present invention is excellent not only in the feeling of use and finish but also in the durability and stability of the ultraviolet ray preventing effect.

[0032]

【Example】

Production Method 1 Hereinafter, the present invention will be described in more detail with reference to specific synthesis examples and examples, but the present invention is not limited to these examples. Here, the average particle diameter and the average plate ratio were measured by the following methods. <Method of Measuring Average Particle Diameter and Average Plate Ratio> The average particle diameter was determined by repeatedly measuring the volume average of 20 arbitrary particles in an arbitrary visual field in a transmission electron micrograph. The arithmetic mean of the major axis and the minor axis of the oval particles was regarded as the particle diameter. The average tabular ratio is calculated by arithmetic mean of all particles from which the plate thickness can be read in the visual field of the transmission electron micrograph.
The average particle thickness was determined by rounding off decimals.

Synthesis Example 1 300 g of a 2 mol molar solution of zinc nitrate and 20 g of sodium sulfate were added to 1 liter of ion-exchanged water, kept at 30 ° C., and 700 g of 2N-NaOH was added under vigorous stirring. The pH immediately after the introduction was 12.3. Slurry 3
The mixture was aged for 0 minutes, heated at 100 ° C. for 1 hour, and then filtered and washed. The obtained wet cake was dried by standing at 110 ° C. until a constant weight was obtained, and pulverized to obtain a white powder. This was identified by a conventional method by powder X-ray diffraction (using Culex using Rotaflex PL200 manufactured by Rigaku Denki).
(measured using a kα ray)). In addition, when the shape was observed with a scanning electron microscope (SEM), it was confirmed that the powder was a powder mainly composed of independent flaky particles having a particle diameter of 1 μm or less without solidification. 0.5 g of this white powder is ultrasonically dispersed in 100 g of acetone, a slide glass is immersed and dried to form a thin film on a glass substrate, and this film is scraped off with a small spatula, and the adhesion to the substrate is measured. As a result, it adhered much more firmly than a film of a commercially available fine zinc white powder (average particle size of 0.15 μm assuming irregular shape and spherical shape, hereinafter referred to as comparative product) treated in the same manner. There was found. Further, when the loose bulk specific volume was measured in accordance with JIS Z 2504, a value of 12 cc / g was shown. This is surprising compared to a value of 1-2 cc / g for the comparative product. Further, when the powder was subjected to spectroscopic measurement, it showed particularly excellent absorption at λmin = 363 nm as compared with the comparative product. On the other hand, the absorbance in the visible part was lower than that of the comparative product, and it was confirmed that the transparency was high. In addition, the visible-ultraviolet spectrum was measured by dispersing the sample in a solvent of water / glycerine = 1/9 and using a UV-265 spectrophotometer manufactured by Shimadzu.

SYNTHESIS EXAMPLES 2 to 7 Examples in which zinc acetate was used instead of zinc nitrate in Synthesis Example 1 (Synthesis Example 2), those in which the amount of sodium sulfate in Synthesis Example 1 was reduced by half (Synthesis Example 3), 4 One part (Synthesis Example 4), one doubling the zinc ion concentration in Synthesis Example 1 (Synthesis Example 5), one using sodium chloride instead of sodium sulfate (Synthesis Example 6), and adding Investigations were conducted on 400 ml of ion-exchanged water and 680 g of 2N-NaOH (Synthesis Example 7) to obtain the same flaky zinc oxide powder. Table 1 shows the measurement results of these various characteristics.

[0035]

[Table 1]

Hereinafter, preparation examples of the water-in-oil type emulsified cosmetic of the present invention will be shown, but the present invention is not limited thereto. The following ether-modified silicones were used. Dimethylsiloxane / methyl (polyoxyethylene) siloxane copolymer A: In the formula (1), R ¹ = R ² = methyl group R ³ = H (OC ₃ H ₆ ) _b (OC ₂ H ₄ ) _a O (CH ₂ ) _p -p = 3, a = 7-15, b = 0 m = 50-100, n = 1-5 Dimethylsiloxane methyl (polyoxypropylene)
Siloxane copolymer B: In the formula (1), R ¹ ＲR ²メ チ ル methyl group R ³ ＣC ₄ H ₉ (OC ₃ H ₆ ) _b (OC ₂ H ₄ ) _a O (CH ₂ ) _p
P = 3, a = 0, b = 7 to 13 m = 4 to 10, n = 1 to 6 Dimethylsiloxane / methyl (polyoxyethylene) siloxane copolymer C: In the formula (1), R ¹ = R ² = methyl group _{^{R 3 = H (OC 3 H}} 6) b (OC 2 H 4) a O (CH 2) p - p = 3, a = 2~5, b = 0 m = 20~30, n = 2-5 lauryl methicone copolyol D: in the formula ^{(2), R 5 = CH} 3, R 6 = C 12 H 25 R 7 = - (OC 2 H 4) p - (OC 3 H 6) q -OH p = 10~30, q = 10~30 Q = - (CH 2) 3 - x = 0, y = 30~70, z = 1~6

Example 1 Using the silicon-treated flaky zinc oxide obtained in Synthesis Example 1,
Creams were prepared according to the formulation shown in Table 2 below, and the feeling of use and the durability were compared. Table 2 shows the results. From Table 2, it was found that only the product 1 of the present invention was excellent in both usability and sustainability.

[0038]

[Table 2]

Example 2 When the cream of Example 2 having the following composition was prepared, it was confirmed that the cream was excellent in use feeling and sustainability. (1) Silicon-treated flaky zinc oxide of Synthesis Example 1 10 (% by weight) (2) Silicone-treated fine particle titanium oxide (30 to 70 nm) 1 (3) Octyl methoxycinnamate 5 (4) α-monomethyl branched isostearyl glyceryl Ether 2 (5) Dimethyl siloxane / methyl (polyoxyethylene) siloxane copolymer A 1 (6) Dimethyl siloxane / methyl (polyoxypropylene) siloxane copolymer B 0.5 (7) Methyl polysiloxane (6cs) 5 (8) Octamethylcyclotetrasiloxane 20 (9) Squalane 2 (10) Myristyl octyl dodecyl 1 (11) Magnesium sulfate 0.5 (12) Glycerin 5 (13) Preservative 0.1 (14) Fragrance trace (15) Purified water balance

Example 3 When the emulsion of Example 3 having the following composition was prepared, it was confirmed that the emulsion was excellent in use feeling and sustainability. (1) Silicon-treated flaky zinc oxide of Synthesis Example 1 10 (% by weight) (2) Silicone-treated fine particle titanium oxide (30 to 70 nm) 0.5 (3) Octyl methoxycinnamate 5 (4) Dimethylsiloxane methyl ( (Polyoxyethylene) siloxane copolymer C 2 (5) dimethylsiloxane methyl (polyoxypropylene) siloxane copolymer B 15 (6) lauryl methicone copolyol D 2 (7) methyl polysiloxane (6cs) 20 (8) Decamethylcyclopentasiloxane 20 (9) Squalane 2 (10) Myristyl octyl dodecyl 1 (11) Silicon-treated talc 3.5 (12) Glycerin 0.1 (13) Preservative 0.1 (14) Fragrance trace (15) Purified water balance

Example 4 When the cream of Example 4 having the following composition was prepared, it was confirmed that the cream was excellent in use feeling and sustainability. (1) Silicon-treated flaky zinc oxide of Synthesis Example 1 10 (% by weight) (2) Fine particle titanium oxide 1 (3) Octyl methoxycinnamate 5 (4) Dimethylsiloxane / methyl (undecylglyceryl ether) siloxane copolymer 2 (5) Dimethylsiloxane / methyl (polyoxyethylene) siloxane copolymer C 0.5 (6) Methylpolysiloxane (6cs) 5 (7) Octamethylcyclotetrasiloxane 20 (8) Squalane 2 (9) Myristyloctyl Dodecyl 1 (10) Magnesium sulfate 0.5 (11) Glycerin 5 (12) Preservative 0.1 (13) Fragrance trace (14) Purified water Balance

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location A61K 7/48 A61K 7/48

Claims (1)

(57) [Claims] 1. The following components (A), (B) and (C): (A) an average particle diameter of 0.1 to 1 μm and an average particle thickness of 0.0
A water-in-oil emulsified cosmetic containing 1 to 0.2 µm and a flaky zinc oxide having an average plate-like ratio of 3 or more (B) ether-modified silicone (C) silicone oil.