JP2001302452A - Cosmetic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cosmetic which exhibits good slippiness and adhesivity to skins, can mask the liver spots and freckles on the skins, and gives non- darkened transparent appearance, gloss and luster. SOLUTION: This cosmetic characterized by formulating thin plate-like α-alumina particles having an average thickness of 0.01 to 0.1 μm and an average particle diameter of 0.5 to 15 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cosmetic comprising thin plate-like α-alumina particles. In particular, the present invention relates to a cosmetic which has a feeling of use showing adhesion to the skin and good slipperiness, makes stains and freckles inconspicuous, and has a transparent feeling free from dullness and an appropriate gloss and luster.

[0002]

2. Description of the Related Art Pigments conventionally incorporated in cosmetics include extenders such as talc, mica, kaolin and sericite, white pigments such as titanium dioxide and zinc oxide, iron oxide, chromium oxide, ultramarine, A coloring pigment such as navy blue and the like, and an ultraviolet ray shielding agent such as fine particle titanium oxide and a brightening agent such as titanium and mica which are mixed according to the purpose are used.

[0003] The extender pigment is a pigment having a small concealing property because it is close to the refractive index of the oil agent used in combination. It is blended in. A white pigment generally has a high refractive index and therefore has a hiding power, and is blended to cover skin spots, freckles, and the like when a cosmetic is applied.

[0004] Coloring pigments are formulated to impart color to the skin and impart a healthy and attractive appearance. Further, an ultraviolet ray shielding agent, a luminous agent and the like are blended and used according to the purpose.

[0005] These various pigments are mixed according to the purpose of the cosmetic, and oils such as higher aliphatic alcohols, higher fatty acids, ester oils, paraffin oils and waxes, and alcohols such as ethyl alcohol, propylene glycol, sorbitol and glucose. , Mucopolysaccharides, collagens, humectants such as lactate, various surfactants, thickeners, antioxidants,
It is manufactured by appropriately adding components such as a PH buffer, a preservative, and a fragrance.

[0006]

In the compounding of the various pigments of the above-mentioned cosmetics, the extender pigments such as talc, mica, kaolin, and sericite are generally flaky particles of naturally occurring silicates. However, these natural products contain iron and other coloring components as impurities, so they can be used together with oils and skin. As time elapses due to perspiration, the sense of transparency is reduced, causing "dullness".

[0007] The extender pigment is also required to have an important property that gives the applied skin a lively and natural luster or luster. Recently, milled mica and the like have been used to respond to this, but this gloss and glossiness are greatly affected by the smoothness and particle thickness of the plate-like particle surface. A certain gloss or gloss has not been imparted.

[0008] Titanium dioxide, which is most frequently used as a white pigment, has a high refractive index and therefore has a large light scattering power and a strong hiding power. However, cosmetics containing such a high-refractive-index pigment in a large amount have too strong a hiding power to exhibit a thick cosmetic feeling and cause a loss of a natural finished feeling. In addition, titanium dioxide generally has strong cohesiveness and a large coefficient of friction, and thus has a problem of deteriorating the usability such as slipperiness.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, a cosmetic which solves the above-mentioned problems can be obtained by blending specific thin plate-like α-alumina particles into the cosmetic. This led to the completion of the present invention.

[0010] That is, the present invention provides a cosmetic composition which has a feeling of use showing adhesion to the skin and good slipperiness, makes spots and freckles inconspicuous, and has a dull, transparent feeling and moderate gloss and luster. Things.

[0011] The term "compounding a specific thin plate-like α-alumina particle" as used herein means that the average thickness of the plate-like particle is 0.1%.
01 μm to 0.1 μm with an average particle size of 0.5 μm to 1
A cosmetic comprising 5 μm thin plate-like α-alumina particles, and the compounding amount is 1 to 90% by weight.

In the present specification, the average thickness of the particles,
Or, with the average particle diameter, select any 10 particles of the present particle group from a scanning electron microscope observation, measure the thickness, the major axis and the minor axis, the thickness is the arithmetic average of the 10 particles, the particle diameter Is the arithmetic mean of 10 (major axis + minor axis) / 2.

Hereinafter, the present invention will be described in detail. The thin plate-like α-alumina particles used in the present invention have an average thickness of 0.3.
01 μm to 0.1 μm, preferably 0.05 μm to
Less than 0.1 μm is good. Average particle size is 0.5 μm to 1
5 μm, preferably 1.0 μm to 10 μm of thin plate-like α-alumina particles are blended.

If the average thickness is 0.1 μm or more, it becomes difficult to impart a natural transparent luster or gloss. In particular, when the edge portion of the plate-like particles is thick, irregular reflection of light occurs, and gloss and gloss with transparency are remarkably reduced. On the other hand, if the average thickness is less than 0.01 μm, the destruction of the particles becomes remarkable in the cosmetic production process, and it becomes difficult to substantially maintain the plate-like shape, and it is difficult to obtain a transparent gloss or luster, which is not preferable.

When the average particle size exceeds 15 μm, the skin becomes rough and the feeling of use is deteriorated. On the other hand, if the average particle size is less than 0.5 μm, there is adhesion, but it is difficult to obtain elongation or slipperiness.

The amount of the thin plate-like α-alumina particles to be added to the cosmetic is 1 to 90% by weight, preferably 5 to 60% by weight.
% By weight. If the content is more than 90% by weight, the moldability of the cosmetic is deteriorated, and the gloss and gloss are undesirably increased. Another one
When the content is less than the weight percentage, the adhesion to the skin and the good slipperiness are reduced, and it becomes difficult to obtain a gloss or luster having a transparent feeling, and the "dullness" of the conventional extender tends to occur.

The use of the cosmetic of the present invention is optional.
It can be used for makeup cosmetics such as foundations, lipsticks, eye shadows, mascaras and the like, and facial cosmetics such as emulsions and creams. Next, the thin plate-like α-alumina particles used in the present invention are produced, for example, as follows.

It is produced by subjecting raw material aluminum hydroxide or alumina hydrate to a hydrothermal treatment in the presence of phosphate ions. A more specific production method is shown below, but the present invention is not limited to this.

Alumina hydrate, such as aluminum hydroxide or boehmite, which is a starting material, is previously pulverized with a ball mill or a stirring medium mill to adjust the particle size.
A raw material particle having a size of 5.0 μm, preferably 0.3 μm to 3.0 μm is used.

In general, the phosphate ion is preferably a phosphoric acid aqueous solution. For example, sodium salts, orthophosphates such as ammonium salts and alkali metal salts such as potassium salts,
Various condensed phosphates such as hexametaphosphate and orthometaphosphate obtained by dehydration-condensation thereof may be used.

The above-mentioned additive is prepared by adding a phosphate ion to 3.0 × 10 ^{−3 to} 2.5 × 1 with respect to 1 mol of aluminum hydroxide.
Within the range of 0 ^-2 mol, preferably 5.0 × 10 ^{−3 to} 1.2.
It is added in a range of × 10 ^-2 mol.

In the hydrothermal synthesis treatment, a 50% by weight slurry containing the above-mentioned starting materials and additives and mixed with water is prepared and filled in a pressure vessel. The synthesis temperature is 350 ° C. or higher, preferably 450 to 600 ° C. In the range of ° C, the synthesis pressure is 50-20
Hydrothermal treatment is performed at 0 atm, preferably at 75 to 150 atm, and at a temperature increasing rate of 5 ° C / min to 0.3 ° C / min until the charged raw material becomes α-alumina particles.

For example, thin plate-like α-alumina particles having an average thickness of 0.01 μm to 0.1 μm and an average particle diameter of 0.5 μm to 15 μm can be obtained by the above-described production method.

In the cosmetic of the present invention, in addition to the above-mentioned thin plate-like α-alumina particles, a higher aliphatic alcohol,
Higher fatty acids, ester oils, paraffin oils, oils such as waxes, ethyl alcohol, propylene glycol, sorbitol, alcohols such as glucose, mucopolysaccharides,
Raw materials used in normal cosmetics such as humectants such as collagens and lactates, various surfactants, thickeners, antioxidants, PH buffers, preservatives, and fragrances are appropriately selected and blended.

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 and Comparative Examples 1 and 2 [Production example of thin plate-like α-alumina powder] Aluminum hydroxide as a starting material was previously pulverized with a ball mill or the like.
The particle size was adjusted to 0 μm. This is mixed with water to prepare a 50% by weight slurry. 5.0 × 10 ⁻³ mol of sodium phosphate was added as a phosphate ion to aluminum hydroxide in the slurry, and the mixture was well mixed and dissolved.

The above-mentioned raw material was filled in a pressure vessel, and kept in an electric furnace at 600 ° C. at a heating rate of 1.6 ° C./min at 75 atm for 3 hours. After cooling the vessel, the vessel was washed with pure water, filtered sufficiently, and dried in a dryer at 100 ° C. for 12 hours to obtain a white powder.

As a result of powder X-ray diffraction, the powder obtained had only the diffraction peak of α-alumina. When the particles were observed with an electron microscope, the average particle size was 2.5 μm.
m, an average thickness of 0.05 μm, and a thin plate-like particle having an aspect ratio of 50.

[Example of Production of General Granular α-Alumina Particles] Aluminum hydroxide having an average particle size of 25 μm, which is a starting material, is placed in an alumina container, and the temperature is raised at a rate of 3.3 ° C. in an electric furnace.
Per minute at 1300 ° C. for 2 hours. After cooling the vessel, it was thoroughly washed with pure water and filtered, pulverized with a wet ball mill for 4 hours to adjust the particle size, and then dried with a 100 ° C. drier.
After drying for 4 hours, a white powder was obtained.

As a result of powder X-ray diffraction, the powder obtained had only the diffraction peak of α-alumina. When the particles were observed with an electron microscope, the average particle size was 3.0 μm.
m, the particle shape was granular or amorphous.

A powder foundation using the above powder was prepared according to the formulation shown in Table 1. The powders (1), (2), (3), (4), (5), and (6) shown in Table 1 were mixed in a Henschel mixer first, and (7), (8), and (9) were dissolved by heating. After well and uniformly mixed with the mixed powder, the mixture was pulverized with a barberizer, and press-molded into a middle plate to obtain a powder foundation. The blending amount in the examples is% by weight.
It is.

Next, the effects of the cosmetics provided by the present thin plate-like α-alumina particles will be described with reference to Examples and Comparative Examples. Four items of transparency were evaluated. The criterion was a five-point evaluation with the highest point being five points, and the average value of five persons was evaluated. The results are as follows.

[0033]

[Table 1]

An oily foundation using the above powder was prepared according to the formulation shown in Table 2. Powder (1) shown in Table-2
(2), (3), (4), (5), and (6) were previously mixed with a Henschel mixer, and the mixture was gradually added to an oil phase in which (7), (8), and (9) were dissolved at 80 ° C. Thereafter, the mixture was sufficiently uniformly dispersed with a homomixer and cooled to room temperature. This mixture was filled in a metal dish to obtain an oily foundation. The compounding amount in the examples is% by weight.

Next, the effects of the cosmetics provided by the present thin plate-like α-alumina particles will be described with reference to Examples and Comparative Examples. Four items of transparency were evaluated. The criterion was a five-point evaluation with the highest point being five points, and the average value of five persons was evaluated. The results are as follows.

[0036]

[Table 2]

[0037]

As described above, the cosmetic obtained by the present invention has good adhesion to the skin and good lubricity due to the particle shape and the smoothness of the surface of the compounded thin plate-like α-alumina powder. Along with showing, due to the concealing effect brought about by an appropriate difference in the refractive index of the α-alumina and the oily component, eliminates skin spots and freckles, and does not contain coloring components such as natural products,
Since the very thin surface has a smooth thin plate-like shape, it is possible to provide a cosmetic that can obtain a transparent feeling free from dullness due to sweat or oil and an appropriate gloss and luster.

Claims (2)

[Claims] An average thickness of the plate-like particles is 0.01 μm or more.
A cosmetic comprising 0.1 μm and thin plate-like α-alumina particles having an average particle diameter of 0.5 μm to 15 μm. 2. The compounding amount of the thin plate-like α-alumina particles is 1
The cosmetic according to claim 1, wherein the amount is from 90 to 90% by weight.