JPH07291615A - Spherical silica supporting zinc oxide, its production and cosmetic - Google Patents

Abstract

PURPOSE:To obtain a cosmetic, excellent in UV light reflectivity and having little decomposition activities of an organic component. CONSTITUTION:This spherical silica supporting zinc oxide comprises the zinc oxide in an amount of 2-80wt.% based on the total amount of spherical silica and zinc oxide is supported in pores of the spherical silica. This method for producing the spherical silica supporting the zinc oxide is to impregnate spherical silica with a solution of a zinc compound, then hydrolyze the zinc compound, further heat-treat and convert the hydrolyzate into the zinc oxide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spherical silica supporting zinc oxide, a method for producing the same, and a cosmetic using the spherical silica supporting zinc oxide, particularly a cosmetic for preventing ultraviolet rays.

[0002]

2. Description of the Related Art Zinc oxide has hitherto been used as an ultraviolet ray reflecting agent in cosmetic raw materials, resin additives, paint additives, and coating agent components such as glass.

Attempts have been made to make the particles finer for the purpose of improving the ultraviolet reflection effect and transparency. For example, in JP-A-60-231607, the maximum particle size is 0.
It has been proposed to blend fine zinc oxide particles having an average particle size of 10 to 60 nm with a particle size of 1 μm or less into cosmetics. Further, in JP-A-62-84017, zinc oxide having an average particle diameter of 20 nm or less is proposed as a cosmetic composition. Further, in JP-A-62-228006, an average particle size of 70
Cosmetics containing zinc oxide of up to 300 nm have been proposed. A coating composition in which zinc oxide having a particle size of 0.1 μm or less is dispersed is proposed in JP-A-2-265976.

However, finely divided zinc oxide has a problem that it tends to agglomerate, is difficult to disperse and blend, and has low transparency in the visible light region and tends to be whitish. In addition, the increase in the specific surface area increases the activity and tends to decompose the blended organic components.

Therefore, in order to improve the dispersibility, Japanese Patent Laid-Open No. 63-119418 proposes a pigment in which fine particles of zinc oxide are fixed to the surface of a carrier with a fixing agent. Further, in order to suppress the decomposition activity, in JP-A-2-49717, composite particles in which zinc oxide is dispersed in mother particles such as nylon resin are disclosed, and in JP-A-3-183620, the surface is made of Al, Si, or the like. Zinc oxide coated with oxide has been proposed.

[0006]

However, in the production of fine particle zinc oxide, there is a problem that a powerful crusher, a dispersing device and other special devices are required, which is expensive. In addition, there is a problem in that the fine zinc oxide particles coated with other metal oxides retain the original shape of the zinc oxide and therefore have a poor feeling when used in cosmetics.

The present invention eliminates the drawbacks of conventional zinc oxide, improves the dispersibility, suppresses the decomposition activity of organic components, and improves the feeling of use even when incorporated into cosmetics. With the goal.

[0008]

The present invention provides a zinc oxide-supporting spherical silica in which 2 to 80% by weight of zinc oxide is supported in the pores of the spherical silica with respect to the total amount of the spherical silica and zinc oxide. To do.

In the present invention, zinc oxide must be supported in the pores of spherical silica. It is preferable that substantially all zinc oxide is present in the pores, but zinc oxide may be present partially on the particle surfaces outside the pores.

The average particle size of the zinc oxide-supporting spherical silica is preferably in the range of 0.5 to 50 μm. The maximum particle size is preferably 200 μm or less. When the average particle diameter is smaller than 0.5 μm, the zinc oxide-supporting spherical silica is apt to aggregate and becomes difficult to disperse, and the slipperiness when compounded in cosmetics is deteriorated, which is not preferable. When the average particle size exceeds 50 μm, or the maximum particle size is 2
If it exceeds 00 μm, a rough feeling occurs when it is mixed with cosmetics, and when it is mixed with a resin or paint, the strength of the resin or coating film is lowered or the smoothness of the coating film is impaired, which is not preferable. . Spherical silica having an average particle diameter of 2 to 20 μm is particularly preferable from the viewpoint of dispersibility, feeling in use, resin strength, and smoothness of coating film.

The shape of the silica particles is required to be spherical, but a part of the shape may be distorted or irregular.

A known method can be used as a method for producing the spherical silica. For example, it can be obtained by dispersing a sodium silicate solution in an organic solvent containing a surfactant, gelling with an acid, and then washing and drying. It can also be obtained by spray drying silica sol.

The crystallite diameter of zinc oxide can be determined from the diffraction line width of powder X-ray diffraction. In the present invention, the following Sc
It was calculated from the Herr's formula. D = Kλ / β cos θ In this formula, D is the crystallite diameter (unit: nm), K is the shape factor (dimensionless constant), λ is the wavelength of X-rays (unit: nm),
β is the diffraction line width (unit: radian), and θ is the diffraction angle. In the present invention, the crystallite diameter was determined with the constant K = 0.9 (reference document “Ceramics characterization technology”, edited by the Ceramics Editing Committee Subcommittee, Japan Ceramic Society (1991)).

The crystallite size of zinc oxide is preferably in the range of 2 to 50 nm when measured by the above method. If the crystallite size is smaller than 2 nm, the ultraviolet ray reflection performance may not be exhibited, which is not preferable. When the crystallite size exceeds 50 nm, zinc oxide cannot be supported in the pores of silica and exists outside the silica particles in a separated state, so that it easily aggregates and is transparent in the visible light region. Is likely to be poor and the decomposition activity becomes strong, which is not preferable. The crystallite diameter of zinc oxide is particularly preferably 4 to 30 nm.

Further, together with zinc oxide, one or more of titanium oxide, iron oxide, cerium oxide and zirconium oxide can be simultaneously loaded. Those that simultaneously support titanium oxide, iron oxide, and cerium oxide can improve the ultraviolet reflection performance. Further, the one in which titanium oxide and zirconium oxide are simultaneously supported exhibits an infrared reflection performance.

Zinc oxide can be doped with other metals to impart various characteristics. As a metal to be doped, an alkali metal, an alkaline earth metal, a trivalent metal such as Al, In, Fe, or a tetravalent metal such as Ti,
A pentavalent metal such as Ce, Zr or Sn, such as V, can be used.

The amount of zinc oxide supported is preferably 2 to 80% by weight based on the total amount of zinc oxide and silica. Carry 2
If it is less than wt%, the ultraviolet ray reflection performance may not be exhibited, which is not preferable. Further, when it exceeds 80% by weight, a large amount of zinc oxide, which is not supported in the pores of silica and exists outside the silica particles, is increased.
It is not preferable because the decomposition activity of the organic component becomes strong. The amount of zinc oxide supported is particularly preferably 10 to 70% by weight.

The spherical silica supporting zinc oxide can be produced by impregnating the spherical silica with a solution of a zinc compound, followed by hydrolysis and heat treatment, or by impregnating the spherical silica with a solution of the zinc compound. The method of thermal decomposition can be preferably adopted.

The zinc compound is not particularly limited as long as a solution can be obtained, but water-soluble inorganic salts or organic salts are preferable. Specific examples of salts include zinc fluoride, zinc chloride, zinc chlorate, zinc sulfate, zinc nitrate, zinc phosphate, zinc carbonate, zinc cyanide, zinc acetate, zinc oxalate, zinc stearate, and potassium zinc sulfate. Zinc ammonium sulfate or the like can be used. In the case of hydrolysis reaction, zinc chloride, zinc sulfate, and zinc nitrate can be preferably used. In the case of thermal decomposition, zinc nitrate, zinc acetate, zinc oxalate, and zinc stearate can be preferably used. It is also possible to use a mixture of two or more zinc compounds.

The spherical silica has a pore volume of 0.2 to 3.0 ml / g and an average pore diameter of 3 to 3 determined by a nitrogen adsorption method.
It is preferably 50 nm.

As a method for impregnating the zinc compound solution, a known method can be used. For example, a method of impregnating spherical silica with a zinc salt solution using a mixer, a kneader, or the like, or a method of adding spherical silica to the zinc salt solution can be used. The spherical silica impregnated with the zinc compound solution can be dried to proceed to the next step, or can be used in a wet state without being dried.

In the case of the hydrolysis method, the hydrolysis temperature may be a temperature at which the solvent remains liquid. When the solvent is water, the range of 15 to 100 ° C is particularly preferable. As the hydrolysis method, either a method of adding an alkali or an acid or a method of heating can be adopted.

In the case of the hydrolysis method, the temperature of the subsequent heat treatment is preferably 70 to 1000 ° C. Heating temperature is 7
If the temperature is lower than 0 ° C. or higher than 1000 ° C., the ultraviolet reflection effect may not be sufficient, which is not preferable. It is considered that when the heat treatment temperature is lower than 70 ° C., the crystallite of zinc oxide may not grow sufficiently. It is also considered that when the heat treatment temperature exceeds 1000 ° C., silica and zinc oxide react with each other to produce zinc silicate having a low ultraviolet reflectivity. The heat treatment temperature is particularly preferably in the range of 200 to 800 ° C.

In the case of the method of thermally decomposing a zinc compound into zinc oxide, the heating temperature may be at least the decomposition temperature of salts, but if it exceeds 1000 ° C. as described above, zinc silicate is formed, which is not preferable.

As the apparatus for heat treatment and heat decomposition, known apparatuses can be adopted. For example, a tunnel kiln, a rotary kiln, an electric furnace, a muffle furnace, a vacuum reduced pressure dryer, etc. can be used.

As the atmosphere for the heat treatment and the heat decomposition, conditions such as air, an oxidizing atmosphere in which the oxygen concentration is controlled, a reducing atmosphere containing hydrogen and the like, and further an inert gas can be arbitrarily adopted. By controlling the atmosphere, oxygen defects or excess zinc defects can be introduced into the supported zinc oxide, and the ultraviolet reflection performance is improved, which is preferable. It can be confirmed that the zinc oxide-supporting spherical silica having such defects introduced therein has a yellowish tint. It can also be confirmed by ESR (electron spin resonance method). That is, although normal zinc cannot be observed by ESR, zinc in the zinc oxide having defects introduced can be detected and confirmed by ESR.

The crystallite size of zinc oxide can be controlled by changing the hydrolysis conditions, heat treatment temperature, heating temperature and the like. Furthermore, the crystallite size of the zinc oxide supported can be controlled by changing the pore diameter of the spherical silica of the carrier. For example, when spherical silica having a small pore diameter is used as a carrier, the crystallite diameter of the zinc oxide carried becomes small, and when the pore diameter becomes large, the crystallite diameter becomes large.

When the surface of the thus-produced zinc oxide-supporting spherical silica is observed with a scanning electron microscope, it is almost the same as the original spherical silica, and the supported zinc oxide is outside the pores. You can see that it has not come out.

It is also possible to simultaneously support one or more of titanium oxide, iron oxide, cerium oxide and zirconium oxide together with zinc oxide. Zinc salts, titanium,
It can be supported by impregnating a salt of iron, cerium or zirconium dissolved in a solvent at the same time or by impregnating each solution separately. further,
It can also be obtained by supporting zinc oxide and then treating with a salt solution of titanium, iron, cerium or zirconium.

Further, the zinc oxide can be doped with another metal. Alkali metal as the metal to be doped,
Alkaline earth metal, trivalent metal such as Al, In, F
A tetravalent metal such as e, such as Ti, Ce, Zr, and Sn, a pentavalent metal such as V, can be used. As the method of dope, the zinc salt and each salt may be simultaneously dissolved in a solvent to impregnate them, or the respective solutions may be impregnated separately to carry them. Further, it can also be obtained by supporting zinc oxide and then treating each with a salt solution.

Spherical silica supporting zinc oxide is suitably blended with conventionally manufactured cosmetics such as foundations, emulsions, lotions, creams, lipsticks, eye shadows, body powders, antiperspirants, shampoos and rinses. be able to. The cosmetics containing the spherical silica supporting zinc oxide have a high effect of preventing ultraviolet rays, have a long lasting effect, and have low decomposability of other components contained in the cosmetics. Further, it has excellent feeling in use such as slipperiness and elongation.

The surface of the spherical silica supporting zinc oxide is Si,
A metal oxide or hydroxide such as Al or Zr, or a resin coated with a resin such as nylon, polyethylene or polypropylene can also be preferably used.

The surface of the zinc oxide-supporting spherical silica or the surface of the above-mentioned coated silica is treated with silicone oil, a silane coupling agent, a titanate coupling agent, an alcohol, a surfactant, other surface treating agents and surface modifying agents. A surface-treated product can also be preferably used. Those treated with these and whose surface is hydrophobized have improved makeup retention when blended into cosmetics, and those treated with a coupling agent have improved strength when blended with resin and have improved dispersion stability. Increase.

Further, by compounding and filling resin, paint or the like with spherical silica supporting zinc oxide, its UV resistance can be improved and its underlayer can be protected from UV rays. In addition, the spherical silica supporting zinc oxide has a low decomposability of organic components mixed at the same time.

[0035]

[Function] Zinc oxide supported on spherical silica has high ultraviolet reflection performance because it is highly dispersed in fine crystals and has high transparency in the visible light region, and at the same time because it exists in the pores. The degradability of other components to be blended is low. Also,
By utilizing the reaction inside the pores of the carrier, highly dispersed zinc oxide can be produced very easily. By using spherical silica as a carrier, the cosmetic material containing it has excellent ultraviolet-reflecting properties and a good feeling of use such as slipperiness. Further, the zinc oxide-supporting spherical silica blended therein has a low decomposability of organic components and is excellent in dispersion stability.

[0036]

【Example】

Example 1 (Production of Zinc Oxide-Supporting Spherical Silica) To 35 g of spherical porous silica having an average particle size of 5 μm (trade name: Sildex, manufactured by Asahi Glass Co., Ltd.), 123 g of 40 wt% zinc sulfate (heptahydrate) aqueous solution (as ZnO) 15 g) was evenly sprayed and allowed to soak, and then dried at 120 ° C. for 30 minutes. This was put into 417 g of a 1N sodium hydroxide aqueous solution at 60 ° C. over 2 minutes while vigorously stirring. After further maintaining the temperature at 60 ° C. for 30 minutes, it was washed with water until no sulfate was detected. After drying at 140 ° C. for 30 minutes, each was heat-treated at the temperature shown in Table 1 for 30 minutes.

The zinc oxide-supporting spherical silica had an average particle diameter of 5 μm, and the amount of zinc oxide supported was 30% by weight. Table 1 shows the crystallite diameter of zinc oxide obtained by X-ray diffraction as described above.

[0038]

[Table 1]

(Evaluation of Ultraviolet Reflecting Properties) 3 g of spherical silica supporting zinc oxide and 7 g of liquid paraffin were mixed (compounding 9% by weight as zinc oxide) and dispersed using three rolls. After sandwiching this with a quartz plate and adjusting the thickness to 30 μm, a self-recording spectrophotometer (U-400 manufactured by Hitachi, Ltd.)
The transmittance was measured with a 0 type). Table 2 shows the transmittance at each wavelength. 500 nm is visible light region, 360 nm, 320 n
m, 290 nm is the ultraviolet light region. The smaller the transmittance is, the better the ultraviolet reflection property is.

Example 2 11 g of spherical porous silica having an average particle diameter of 5 μm (trade name: Sildex, manufactured by Asahi Glass Co., Ltd.) was uniformly sprayed with 64 g of a 38 wt% zinc acetate aqueous solution, and dried at 120 ° C. for 30 minutes. This was heated to 600 ° C. at a rate of 10 ° C./min, and decomposed by heating at 600 ° C. for 30 minutes. This zinc oxide-supporting spherical silica has an average particle size of 5 μm and a supported amount of 34% by weight.
And the crystallite size was 8.8 nm. In the same manner as in Example 1, the ultraviolet reflection characteristics were evaluated (containing 9% by weight of zinc oxide). The results are shown in Table 2.

Comparative Example Sakai Chemical Co., Ltd. product name FINEX as fine particle zinc oxide
-25 (average particle size 0.04 μm, crystallite size 19 nm)
Was used as is. Table 2 shows the ultraviolet ray reflection characteristics when this was mixed with 9% by weight of liquid paraffin.

[0042]

[Table 2]

As can be seen from Table 2, the zinc oxide-supporting spherical silica of the present invention is excellent in the ultraviolet reflecting property and the transparency in the visible light region, even though the same 9% by weight as zinc oxide is blended.

Example 3 With respect to the samples of Examples 1-2, 2 and Comparative Example, 9% by weight of zinc oxide was dispersed in isopropyl alcohol (2-propanol) and exposed to sunlight for 5 days. Table 3 shows the conversion rate (mol basis) of the decomposition reaction from isopropyl alcohol to acetone.

[0045]

[Table 3]

Thus, it is understood that the zinc oxide-supporting spherical silica of the present invention has a low decomposability of isopropyl alcohol.

Example 4 (Production of cosmetics) A foundation having the composition shown in Table 4 was produced. However, the mixing ratio is% by weight.

[0048]

[Table 4] (1) Zinc oxide-supporting spherical silica of Example 1-2 30.0 (2) Talc 8.0 (3) Sericite 8.0 (4) Colored pigment Appropriate amount (5) Solid paraffin 5.5 (6) Carnauba wax 3.3 (7) Liquid paraffin 37.1 (8) Sorbitan monooleate 3.3

First, (1) to (4) were mixed well, about half of (7) and (8) were added thereto, and the mixture was uniformly dispersed with a homomixer, and then the remaining components were heated and melted and added. Mix well. This was poured into a container and cooled and solidified to produce a foundation having a high ultraviolet reflection effect and a good feeling in use. In addition, the dispersion stability after one month was good, and no discoloration or odor was observed.

Example 5 In the same manner as in Example 4 except that the zinc oxide-supporting spherical silica of Example 2 was used as the component (1) of Example 4, a foundation having a high ultraviolet reflection effect and a good feeling in use was produced. Also, 1
The dispersion stability after a month was also good, and no discoloration was observed.

[0051]

EFFECTS OF THE INVENTION The zinc oxide-supporting spherical silica of the present invention has the following effects because the fine particles of zinc oxide are supported in the pores of the silica in a highly dispersed manner. (1) High UV reflection performance, (2) High transparency in the visible light region,
(3) Low decomposition activity. Further, according to the method for producing zinc oxide-supporting spherical silica of the present invention, (4) spherical silica in which fine particles of zinc oxide are highly dispersed can be easily produced without using a special apparatus or technique. (5)
Effects such as easy control of the crystallite size of zinc oxide are achieved. Furthermore, by blending the zinc oxide-supporting spherical silica of the present invention in a cosmetic product, effects such as excellent ultraviolet ray reflection characteristics, high transparency in the visible light region, and good feel when applied to the skin are achieved. It

Further, by compounding and filling resin, paint or the like with spherical silica carrying zinc oxide, its UV resistance can be improved and its underlayer can be protected from UV rays. In addition, the spherical silica supporting zinc oxide has an effect that the decomposability of other components mixed at the same time is low.

The zinc oxide-supporting spherical silica of the present invention is made of paper,
By using it as a component of a coating agent such as glass and film, the same effect as described above can be achieved.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunihiko Terase 10 Goi Kaigan, Ichihara City, Chiba Asahi Glass Co., Ltd. Chiba Factory

Claims (5)

[Claims] 1. A zinc oxide-supporting spherical silica in which 2 to 80% by weight of zinc oxide is supported in the pores of the spherical silica with respect to the total amount of the spherical silica and zinc oxide. 2. The supported zinc oxide has a crystallite size of 2 to 50.
The spherical silica supporting zinc oxide according to claim 1, wherein the spherical silica has a thickness of nm. 3. A method for producing a zinc oxide-supporting spherical silica, which comprises impregnating spherical silica with a solution of a zinc compound, hydrolyzing it, and further heat treating it to obtain zinc oxide. 4. A method for producing spherical silica carrying zinc oxide, which comprises impregnating spherical silica with a solution of a zinc compound and then thermally decomposing the zinc compound to produce zinc oxide. 5. A cosmetic comprising the zinc oxide-supporting spherical silica according to claim 1 or 2 incorporated therein.