JP2020132492A - Zinc compound for cosmetics, and method for manufacturing same - Google Patents

Abstract

To provide a zinc compound for cosmetics which achieves excellent use feeling when blended into cosmetics and prevents oil flotation and makeup deterioration of the cosmetics, thereby maintaining makeup for a longer time than conventional ones.SOLUTION: A tabular zinc compound for cosmetics has a full length of 5-50 μm. An aspect ratio that is a ratio of the full length and a thickness is 6-100. When preparing an oil and fat mixture in which a content of the zinc compound for cosmetics reaches 10 wt% or more by being added to oil and fat including C-Cmonounsaturated fatty acid, flowability of the oil and fat mixture is designed to decrease or disappear in 2-10 minutes.SELECTED DRAWING: None

Description

The present invention relates to a plate-shaped zinc compound for cosmetics and a method for producing a zinc compound for cosmetics.

In general, cosmetics used for facial makeup and the like are required to have performances such as less likely to cause oil floating due to sebum, less likely to cause makeup breakage, and excellent usability. Zinc oxide has been conventionally used as one of the raw materials for cosmetics for improving these performances. Zinc oxide is white fine particles that affect the "slipperiness" and "adhesion to the skin" related to the feeling of use of cosmetics, and solidifies or gels the fatty acid by reacting with fatty acids such as oleic acid. It has the property of being converted. When make-up is performed using a cosmetic containing zinc oxide, zinc oxide acts on the fatty acids contained in the sebum that exudes from the pores of the skin to suppress the diffusion of the sebum, and even after a certain amount of time has passed after the make-up, the cosmetic Oil floating and makeup breakage are less likely to occur.

By the way, the performance (physical properties) of zinc oxide depends on properties such as shape, crystal structure, and specific surface area. The applicant has developed needle-shaped zinc oxide (Patent Document 1) and spherical zinc oxide (Patent Document 2) as zinc oxide that can be used in cosmetics, and has incorporated these into various cosmetics. Various studies have been conducted. Patent Document 1 describes that a cosmetic containing acicular zinc oxide powder has an excellent effect of spreading, spreading and hiding wrinkles. Patent Document 2 describes that a cosmetic containing spherical zinc oxide powder has excellent transparency, usability, and long-lasting makeup when applied to the skin.

Japanese Unexamined Patent Publication No. 2015-8201 Japanese Unexamined Patent Publication No. 2016-160165

In order to prevent oil floating and makeup breakage of cosmetics and maintain makeup for a long period of time, zinc oxide contained in cosmetics and fatty acids contained in sebum are efficiently reacted to quickly and uniformly make sebum uniform. Is required to be solidified or gelled. However, the findings obtained from the zinc oxide that has been developed so far have fully clarified what kind of properties zinc oxide has, which reacts efficiently with fatty acids and is the most suitable raw material for cosmetics. I couldn't say there was. That is, even in the cosmetics containing the acicular zinc oxide powder of Patent Document 1 and the cosmetics containing the spherical zinc oxide powder of Patent Document 2, the oil floating and the makeup breakage of the cosmetics last for a longer period of time. There was still room for improvement in terms of prevention. Further, it is required to accumulate further knowledge about the feeling of use of cosmetics containing zinc oxide.

Further, as a typical method for producing zinc oxide, a method using a solution reaction of a water-soluble zinc compound is known, but in the solution reaction, the reaction mechanism and reaction rate change depending on the addition conditions and timing of the zinc raw material solution. It may be difficult to stably produce zinc oxide having certain properties. The needle-shaped zinc oxide powder of Patent Document 1 and the spherical zinc oxide powder of Patent Document 2 also use an aqueous solution of a water-soluble zinc compound as the zinc raw material solution, but the zinc raw material solution used in the solution reaction is used. No particular detailed study has been made on the addition conditions and the like.

The present invention has been made in view of the above problems, and while achieving an excellent usability when blended in a cosmetic, it prevents oil floating and makeup breakage of the cosmetic, and takes a longer time than before. An object of the present invention is to provide a zinc compound for cosmetics capable of maintaining make-up over time. Another object of the present invention is to provide a method for producing a zinc compound for cosmetics for stably producing a zinc compound for cosmetics having certain properties.

The characteristic composition of the zinc compound for cosmetics according to the present invention for solving the above problems is as follows.
A plate-shaped zinc compound for cosmetics
The total length is 5 to 50 μm, and the aspect ratio, which is the ratio of the total length to the thickness, is 6 to 100.

As a result of diligent research, the present inventors have found that among many types of zinc compounds, zinc compounds having a plate-like morphology are excellent in the ability to solidify or gel fatty acids contained in sebum. If such a plate-shaped zinc compound for cosmetics has a total length of 5 to 50 μm and an aspect ratio of 6 to 100, which is the ratio of the total length to the thickness, only the feeling of use when blended in cosmetics. However, they found that they were particularly excellent in the ability to solidify or gel fatty acids, and came up with the creation of a plate-shaped zinc compound for cosmetics having this composition. Therefore, when the zinc compound for cosmetics having this composition is used as a raw material for cosmetics, when the cosmetic is applied to the skin such as the face, the fatty acids contained in sebum efficiently react with the zinc compounds contained in the cosmetics. , Sebum will be rapidly and uniformly solidified or gelled. As a result, oil floating and makeup breakage of the cosmetic are prevented, and the makeup can be maintained for a longer period of time than before. In addition, the feeling of use when blended in cosmetics is also excellent.

In the zinc compound for cosmetics according to the present invention
When a fat / oil mixture having a content of 10% by weight or more is prepared by adding it to a fat / oil containing C _{16 to} C ₂₀ monounsaturated fatty acids, the fluidity of the fat / oil mixture is reduced or disappears in 2 to 10 minutes. It is preferably set to.

The main component of sebum is C _16- C ₂₀ monounsaturated fatty acids. Therefore, when a plate-shaped zinc compound for cosmetics is mixed and prepared with an oil or fat containing C _{16 to} C ₂₀ monounsaturated fatty acids so that the concentration is 10% by weight or more, the fluidity of the oil or fat mixture is 2 to 10 If it is reduced or disappears in minutes, the zinc compound for cosmetics having this composition has good usability as a raw material for cosmetics and has a good usability when blended in cosmetics, but oil floating due to sebum and oil floating. Makeup breakage is less likely to occur. Therefore, it can be extremely useful as a raw material for cosmetics.

The characteristic configuration of the method for producing a zinc compound for cosmetics according to the present invention for solving the above problems is
A method for producing a plate-shaped zinc compound for cosmetics.
A preparatory step for preparing a first aqueous solution in which an alkali metal hydroxide is dissolved and a second aqueous solution in which a water-soluble zinc compound and a hydrolyzable alkalinable nitrogen-containing compound are dissolved, respectively.
A crystal generation step of dropping a part of the second raw material aqueous solution into the first raw material aqueous solution to form a seed crystal of a zinc hydroxide compound in the liquid.
A crystal growth step of dropping the remainder of the second raw material aqueous solution into a mixed solution containing seed crystals to grow crystals, and
A separation step of separating the crystals from the mixed solution containing the crystals,
A heat treatment step of drying and firing the separated crystals,
To include.

In the method for producing a zinc compound for cosmetics having the present constitution, the first aqueous solution is alkaline, and by starting from such an alkaline environment and adding the second aqueous solution in two steps, crystal formation and Crystal growth proceeds at each stage to produce crystals of the zinc hydroxide compound. Then, zinc oxide can be obtained by heat-treating the crystals of the produced zinc hydroxide compound. This zinc oxide has a plate-like shape and is useful as a raw material for cosmetics because it has an excellent feeling of use when blended in cosmetics and the ability to solidify or gel fatty acids contained in sebum. It will be something like that.

In the method for producing a zinc compound for cosmetics according to the present invention.
In the preparatory step, the concentration of the alkali metal hydroxide in the first aqueous solution is adjusted to 0.1 to 0.7 mol / L, and the concentration of the water-soluble zinc compound in the second aqueous solution is 0.2. It is preferable to adjust the concentration of the hydrolyzable alkalinable nitrogen-containing compound to ~ 4 mol / L to 0.4 to 12 mol / L.

In the method for producing a zinc compound for cosmetics having the present constitution, a feeling of use when blended in cosmetics by advancing the solution reaction using the first raw material aqueous solution and the second raw material aqueous solution adjusted to the above concentrations. , And a zinc oxide compound for cosmetics containing zinc oxide, which is particularly excellent in the ability to solidify or gel fatty acids contained in sebum, can be efficiently and easily produced. Further, since such a manufacturing method can be applied to mass production, it can be applied to industrial manufacturing.

In the method for producing a zinc compound for cosmetics according to the present invention.
The crystal formation step is preferably carried out until the hydrogen ion concentration (pH) of the mixed solution is reduced to 11 or less.

In the method for producing a zinc compound for cosmetics having this constitution, by carrying out the crystal formation step until the hydrogen ion concentration (pH) of the mixed solution is reduced to 11 or less, fine crystals of the zinc hydroxide compound are contained in the solution. (Seed crystals) are likely to be produced in large quantities.

In the method for producing a zinc compound for cosmetics according to the present invention.
The crystal forming step preferably includes a first aging step of aging the produced seed crystal.

In the method for producing a zinc compound for cosmetics having this constitution, by performing the first aging step of aging the seed crystal at the time of crystal formation, the properties of the seed crystal can be stabilized and the subsequent crystal growth can be surely performed. It will be possible.

In the method for producing a zinc compound for cosmetics according to the present invention.
In the crystal formation step, it is preferable to maintain the liquid temperature of the first raw material aqueous solution at 70 to 95 ° C. before dropping the second raw material aqueous solution.

In the method for producing a zinc hydroxide compound for cosmetics having the present constitution, by maintaining the liquid temperature of the first raw material aqueous solution at 70 to 95 ° C. before dropping the second raw material aqueous solution, the zinc hydroxide compound can be contained in the liquid. A large amount of microcrystals are generated, which become seed crystals, and subsequent crystal growth can be efficiently promoted.

In the method for producing a zinc compound for cosmetics according to the present invention.
The crystal growth step preferably includes a second aging step of aging the grown crystal.

In the method for producing a zinc compound for cosmetics having this constitution, the growth of the zinc hydroxide compound crystal is promoted by performing the second aging step of aging the crystal at the time of crystal growth, and the crystal size is appropriately large. It becomes. If the crystals of such a zinc hydroxide compound are heat-treated, they have a good feeling of use when blended in cosmetics and the ability to solidify or gel fatty acids contained in sebum, but they are easy to handle. Zinc oxide can be obtained.

In the method for producing a zinc compound for cosmetics according to the present invention.
The heat treatment step is preferably carried out in a state where the crystals are crushed.

In the method for producing a zinc compound for cosmetics having this constitution, by carrying out a heat treatment step in a state where the crystals are crushed, the zinc hydroxide contained in the zinc hydroxide compound is converted to zinc oxide (dehydration reaction). It progresses reliably, and zinc oxide suitable for high-purity cosmetics can be obtained.

FIG. 1 is an electron micrograph of zinc oxide of Example 1. FIG. 2 is a graph showing changes in the hydrogen ion concentration (pH) of the raw material mixed solution in Example 1. FIG. 3 is an electron micrograph of zinc oxide of Example 2. FIG. 4 is an electron micrograph of zinc oxide of Example 3. FIG. 5 is an electron micrograph of zinc oxide of Example 4. FIG. 6 is an electron micrograph of zinc oxide of Example 5. FIG. 7 is an electron micrograph of zinc oxide of Example 6. FIG. 8 is an electron micrograph of zinc oxide of Example 7. FIG. 9 is an electron micrograph of zinc oxide of Example 8. FIG. 10 is an electron micrograph of zinc oxide of Example 9. FIG. 11 is an electron micrograph of zinc oxide of Comparative Example 1. FIG. 12 is an electron micrograph of zinc oxide of Comparative Example 2. FIG. 13 is an electron micrograph of zinc oxide of Comparative Example 3. FIG. 14 is an electron micrograph of zinc oxide of Comparative Example 4. FIG. 15 is an electron micrograph of zinc oxide of Comparative Example 5.

The zinc compound for cosmetics and the method for producing the zinc compound for cosmetics of the present invention will be described in detail. However, the present invention is not intended to be limited to the embodiments and examples described below.

<Zinc compounds for cosmetics>
As the name implies, the zinc compound for cosmetics of the present invention is used as a raw material for cosmetics (for example, foundation, blusher, eye shadow, mascara, eyeliner, etc.). The zinc compound contains zinc oxide as a main component, and the zinc compound may contain a zinc hydroxide compound that is a precursor of zinc oxide and remains in the production process. However, the zinc oxide compound for cosmetics of the present invention is dominated by the characteristics of zinc oxide as a whole, and there is no particular problem even if it is regarded as zinc oxide. Therefore, in the following description, the zinc compound is treated as zinc oxide. And.

The zinc oxide of the present invention is obtained as a crystalline metal oxide having a plate-like morphology. The size of zinc oxide is set to 5 to 50 μm in total length, preferably 10 to 45 μm. The aspect ratio is set to 6 to 100, preferably 10 to 70. Here, the total length of zinc oxide means the maximum width (major axis) when the plate-shaped zinc oxide is viewed upward. The aspect ratio means the ratio of the total length to the thickness of a plate crystal. The total length and thickness of zinc oxide can be easily specified as an average value of measured values of the total length and thickness of each crystal particle by arbitrarily extracting a plurality of crystal particles from an electron micrograph. Zinc oxide having such a form is particularly excellent not only in the feeling of use when blended in cosmetics, but also in the ability to solidify or gel fatty acids (particularly C _{16 to} C ₂₀ monounsaturated fatty acids). Such characteristics were first clarified by the research of the present inventors.

Therefore, the use of zinc oxide of the present invention as a raw material for cosmetics, when applying the cosmetics on the skin such as the face, including the fatty acids (mainly oleic acid, a C ₁₈ monounsaturated fatty acids) in the sebum It reacts efficiently with zinc oxide contained in cosmetics, and sebum is rapidly and uniformly solidified or gelled. As a result, oil floating and makeup breakage of the cosmetics are prevented, the makeup can be maintained for a longer period of time than before, and the feeling of use when blended in the cosmetics is also excellent.

When the zinc oxide of the present invention is added to a fat or oil containing C _{16 to} C ₂₀ monounsaturated fatty acids to prepare a fat or oil mixture having a content of 10% by weight or more, the fluidity of the fat or oil mixture is 2 to 10 It is preferably set to reduce or disappear in minutes. Here, the fluidity of the oil / fat mixture is such that, for example, when the oil / fat mixture is dropped onto a glass plate placed horizontally and the glass plate is shaken, the oil / fat mixture does not flow out. It can be determined that the sex has disappeared. Further, even if the oil / fat mixture slightly flows out due to the shaking of the glass plate, if the flow amount (flow distance on the glass plate) is 1/2 or less of the original flow amount of the oil / fat, the fluidity is high. It can be judged that it has decreased. Zinc oxide, which can exhibit solidification or gelling performance against such fats and oils, is easy to use as a raw material for cosmetics and has a good usability when blended in cosmetics, but oil floats and makeup breaks due to sebum. Is less likely to occur. Therefore, the zinc oxide of the present invention can be extremely useful as a raw material for cosmetics.

<Manufacturing method of zinc compounds for cosmetics>
The zinc oxide (zinc compound for cosmetics) of the present invention is produced by a reaction utilizing hydrolysis of a hydrolyzable alkalinable nitrogen-containing compound in an aqueous solution containing a water-soluble zinc compound in an alkaline environment. Is. Hereinafter, each step in the method for producing zinc oxide of the present invention will be described.

First, as a preparatory step, an alkaline aqueous solution in which an alkali metal hydroxide is dissolved (this is used as a first raw material aqueous solution) and a zinc-containing solution in which a water-soluble zinc compound and a hydrolyzable alkalinable nitrogen-containing compound are dissolved are contained. An aqueous solution (referred to as a second raw material aqueous solution) is prepared respectively. Examples of the alkali metal hydroxide for preparing the first raw material aqueous solution include sodium hydroxide and potassium hydroxide, and sodium hydroxide is particularly preferably used. Examples of the water-soluble zinc compound for preparing the second raw material aqueous solution include zinc sulfate, zinc chloride, zinc acetate, and zinc nitrate, and zinc sulfate and zinc chloride are preferably used among these. Examples of the hydrolyzable alkalinable nitrogen-containing compound include urea and hexamethylenetetramine, and urea is preferably used in terms of availability and cost.

In the preparation of the first raw material aqueous solution, the alkali metal hydroxide contained in the prepared aqueous solution is preferably 0.4 to 0.5 mol / L so as to be 0.1 to 0.7 mol / L. The concentration is adjusted so as to. In this case, the hydrogen ion concentration (pH) of the first raw material aqueous solution is 12 or more. In the preparation of the second raw material aqueous solution, the concentration of the water-soluble zinc compound contained in the prepared aqueous solution is adjusted so as to be 0.2 to 4 mol / L, preferably 0.6 to 2 mol / L. Further, the concentration of the hydrolyzable alkalinable nitrogen-containing compound contained in the prepared aqueous solution is adjusted to be 0.4 to 12 mol / L, preferably 1.2 to 9 mol / L. .. By advancing the solution reaction using the first aqueous solution and the second aqueous solution adjusted to the above concentrations, the zinc hydroxide compound which is the precursor of zinc oxide of the present invention can be efficiently and easily produced. Is possible. Further, since such a manufacturing method can be applied to mass production, it can be applied to industrial manufacturing.

The reaction mechanism in the method for producing zinc oxide of the present invention is a reaction in which microcrystals of a zinc hydroxide compound to be a seed crystal (nucleus) are generated in an aqueous solution and grown. That is, by executing the crystal formation step (first step) and the crystal growth step (second step) described below, crystals of a zinc hydroxide compound serving as a precursor of zinc oxide can be obtained.

In the crystal formation step, a part of the second raw material aqueous solution is added dropwise to the first raw material aqueous solution (first stage) to generate seed crystals of the zinc hydroxide compound in the liquid. Then, in order to stabilize the seed crystal, aging is performed as necessary. In the crystal formation step, it is preferable to heat the first raw material aqueous solution in advance to maintain a constant liquid temperature. At that time, the liquid temperature of the first raw material aqueous solution is preferably 70 to 95 ° C, more preferably 80 to 90 ° C. As a result, a large amount of fine crystals of the zinc hydroxide compound are generated in the liquid, which become seed crystals, and it becomes possible to efficiently proceed with the subsequent crystal growth. The dropping amount of the second raw material aqueous solution is preferably 0.2 to 0.9 times, more preferably 0.5 to 0.8 times the amount of the entire second raw material aqueous solution. When the second raw material aqueous solution is added dropwise to the first raw material aqueous solution under the above conditions, the pH of the mixed solution gradually decreases, so that seed crystals are stably produced. The dropping of the second raw material aqueous solution into the first raw material aqueous solution is preferably carried out until the pH of the mixed solution is reduced to 11 or less. This facilitates the formation of a large amount of zinc hydroxide compound microcrystals (seed crystals) in the liquid.

In the crystal growth step, the remainder of the second aqueous solution is added dropwise to the mixed solution containing the seed crystal (second stage) to grow the crystal. The remaining portion of the second aqueous solution (second stage) may be dropped at once (that is, continuously) or divided into a plurality of times (that is, intermittently). is there. Then, in order to promote the growth of crystals, aging is performed as necessary. The liquid temperature of the mixed liquid when the remainder of the second raw material aqueous solution is dropped may be the same as or lower than the liquid temperature (70 to 95 ° C.) in the crystal formation step. Further, it is preferable to add the remaining portion of the second raw material aqueous solution to the mixed solution while stirring little by little. As a result, the seed crystals in the mixed solution can efficiently grow into plate-shaped crystals. If the remainder of the second aqueous solution is added dropwise to the mixed solution under the above conditions, the final pH of the mixed solution will settle in the range of 5 to 6, which is weakly acidic, so that crystal growth will be appropriately promoted and the aspect ratio will be increased. A moderately large plate-like crystal is stably produced.

The crystals obtained by the above solution reaction are crystals of a zinc hydroxide compound containing zinc hydroxide as a main component. Therefore, a separation step of separating the crystals from the mixed solution containing the crystals is carried out, and a heat treatment step of drying and firing the separated crystals is further carried out. The separation step can be performed using a filter press, a centrifuge, or the like. In the heat treatment step, drying and firing may be continuously performed as a series of steps in the firing furnace, or may be performed once in the dryer and then fired in the firing furnace. The drying conditions are preferably at a temperature of 30 to 100 ° C. for 0.5 to 3 hours. The firing conditions are preferably 400 to 800 ° C. for 1 to 5 hours. When the crystals of the zinc hydroxide compound are heat-treated, the zinc hydroxide contained in the zinc hydroxide compound is converted to zinc oxide by the dehydration reaction. The heat treatment step is preferably performed in a state where the crystals are crushed. As a result, the conversion of zinc hydroxide to zinc oxide (dehydration reaction) proceeds reliably, and the cosmetic of the present invention having a total length of 5 to 50 μm and an aspect ratio of 6 to 100 suitable for cosmetics having high crystallinity and purity. Zinc oxide can be obtained.

Zinc oxide according to the present invention was produced under various conditions, and their characteristics were evaluated (Examples 1 to 9). For comparison, zinc oxide was produced under conditions different from those of the present invention, and the characteristics were evaluated in the same manner (Comparative Examples 1 to 5). Table 1 summarizes the zinc oxide production conditions of Examples and Comparative Examples, and a specific production method will be described below.

[Example 1]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 1. It was. This zinc oxide had a total length (major axis) of 15 μm, an aspect ratio of 50, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 1 is shown in FIG. In addition, a graph showing changes in the hydrogen ion concentration (pH) of the obtained raw material mixed solution when adding zinc sulfate / urea mixed aqueous solution (second raw material aqueous solution) to the sodium hydroxide aqueous solution (first raw material aqueous solution) is shown in the figure. Shown in 2. According to FIG. 2, the pH of the mixed solution became 10.9 by dropping the first-stage zinc sulfate / urea mixed aqueous solution to the sodium hydroxide aqueous solution, and after aging, the second-stage zinc sulfate / urea mixed aqueous solution was added. The pH of the mixed solution dropped sharply when the dropping of the mixture was started, and then the pH of the mixed solution gradually decreased gradually, and finally the pH of the mixed solution settled at around 5.5.

[Example 2]
As the first aqueous solution, 500 mL of sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and as the second aqueous solution, 2.0 mol / L zinc sulfate and 4.0 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 50 mL (0.2 times amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 200 mL (0.8 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 2. It was. This zinc oxide had a total length (major axis) of 18 μm, an aspect ratio of 60, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 2 is shown in FIG.

[Example 3]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.5 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 3. It was. This zinc oxide had a total length (major axis) of 20 μm, an aspect ratio of 60, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 3 is shown in FIG.

[Example 4]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 120 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 4. It was. This zinc oxide had a total length (major axis) of 25 μm, an aspect ratio of 70, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 4 is shown in FIG.

[Example 5]
As the first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 9.0 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 5. It was. This zinc oxide had a total length (major axis) of 13 μm, an aspect ratio of 40, and had a plate-like shape. An electron micrograph of zinc oxide of Example 5 is shown in FIG.

[Example 6]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 600 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 6. It was. This zinc oxide had a total length (major axis) of 20 μm, an aspect ratio of 60, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 6 is shown in FIG.

[Example 7]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 100 mL (0.4 times the amount) of the zinc sulfate / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 800 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 7. It was. This zinc oxide had a total length (major axis) of 20 μm, an aspect ratio of 60, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 7 is shown in FIG.

[Example 8]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.5 mol / L sodium hydroxide was prepared, and as a second raw material aqueous solution, 1.0 mol / L zinc chloride and 2.0 mol / L urea were prepared. 250 mL of a zinc chloride / urea mixed aqueous solution containing the above was prepared. The sodium hydroxide aqueous solution was heated to 90 ° C., and 100 mL (0.4 times amount) of the zinc chloride / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc chloride / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 400 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 8. It was. This zinc oxide had a total length (major axis) of 20 μm, an aspect ratio of 13, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 8 is shown in FIG.

[Example 9]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.5 mol / L sodium hydroxide was prepared, and as a second raw material aqueous solution, 2.0 mol / L zinc chloride and 2.0 mol / L urea were prepared. 250 mL of a zinc chloride / urea mixed aqueous solution containing the above was prepared. The sodium hydroxide aqueous solution was heated to 90 ° C., and 100 mL (0.4 times amount) of the zinc chloride / urea mixed aqueous solution was added dropwise over 10 minutes with stirring (first step). The hydrogen ion concentration (pH) of the mixed solution after dropping was 11 or less, and it was confirmed that innumerable seed crystals of the zinc hydroxide compound were precipitated in the solution. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc chloride / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 400 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Example 9. It was. This zinc oxide had a total length (major axis) of 6 μm, an aspect ratio of 6, and had a plate-like morphology. An electron micrograph of zinc oxide of Example 9 is shown in FIG.

[Comparative Example 1]
500 mL of water was prepared in place of the first aqueous solution, and 250 mL of a zinc sulfate / urea mixed aqueous solution containing 2.0 mol / L zinc sulfate and 4.0 mol / L urea was prepared as the second aqueous solution. Water was heated to 90 ° C., and 250 mL of a total amount of a zinc sulfate / urea mixed aqueous solution was added dropwise over 60 minutes with stirring to form crystals of a zinc hydroxide compound in the solution. The crystals were aged by stirring the liquid after dropping for 30 minutes as it was, and then the crystals were separated from the liquid and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Comparative Example 1. It was. This zinc oxide had a total length (major axis) of 50 μm, an aspect ratio of 125, and had a plate-like morphology. An electron micrograph of zinc oxide of Comparative Example 1 is shown in FIG.

[Comparative Example 2]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.75 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The sodium hydroxide aqueous solution is heated to 90 ° C., and 100 mL (0.4 times amount) of the zinc sulfate / urea mixed aqueous solution is added dropwise over 10 minutes with stirring (first stage), and the zinc hydroxide compound is added to the solution. Seed crystals were produced. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc sulfate / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Comparative Example 2. It was. This zinc oxide did not have a plate-like morphology. An electron micrograph of zinc oxide of Comparative Example 2 is shown in FIG.

[Comparative Example 3]
500 mL of water was prepared in place of the first aqueous solution, and 250 mL of a zinc chloride / urea mixed aqueous solution containing 1.0 mol / L zinc chloride and 2.0 mol / L urea was prepared as the second aqueous solution. The sodium hydroxide aqueous solution is heated to 90 ° C., and 100 mL (0.4 times amount) of the zinc chloride / urea mixed aqueous solution is added dropwise over 10 minutes with stirring (first stage), and the zinc hydroxide compound is added to the solution. Seed crystals were produced. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc chloride / urea mixed aqueous solution is applied for 60 minutes while stirring the mixed solution. And dropped (second stage) to grow crystals. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 400 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Comparative Example 3. It was. This zinc oxide did not have a plate-like morphology. An electron micrograph of zinc oxide of Comparative Example 3 is shown in FIG.

[Comparative Example 4]
As the first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.5 mol / L sodium hydroxide was prepared, and 250 mL of a zinc chloride aqueous solution containing 1.0 mol / L zinc chloride was used instead of the second raw material aqueous solution. Prepared. The sodium hydroxide aqueous solution is heated to 90 ° C., and 100 mL (0.4 times amount) of the zinc chloride aqueous solution is added dropwise over 10 minutes with stirring (first stage)), and the zinc hydroxide compound seeds are contained in the solution. Crystals were generated. Next, the seed crystal is aged by stirring the mixed solution containing the seed crystal as it is for 10 minutes, and then 150 mL (0.6 times amount) of the remaining zinc chloride aqueous solution is added dropwise over 60 minutes while stirring the mixed solution. (Second stage), crystals were grown. It was confirmed that the crystal after growth was a plate-shaped crystal of zinc hydroxide compound. Next, the crystals were aged by stirring the mixed solution as it was for 30 minutes, and then the crystals were filtered off from the mixed solution and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 400 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Comparative Example 4. It was. This zinc oxide had a total length (major axis) of 20 μm, an aspect ratio of 5, and had a plate-like morphology. An electron micrograph of zinc oxide of Comparative Example 4 is shown in FIG.

[Comparative Example 5]
As a first raw material aqueous solution, 500 mL of a sodium hydroxide aqueous solution containing 0.4 mol / L sodium hydroxide was prepared, and further, as a second raw material aqueous solution, 0.6 mol / L zinc sulfate and 1.2 mol / L urea were prepared. 250 mL of a zinc sulfate / urea mixed aqueous solution containing the above was prepared. The aqueous sodium hydroxide solution was heated to 90 ° C., and 250 mL of the total amount of the zinc sulfate / urea mixed aqueous solution was added dropwise over 1 minute with stirring to generate crystals of the zinc hydroxide compound in the solution. The crystals were aged by stirring the liquid after dropping for 30 minutes as it was, and then the crystals were separated from the liquid and washed with water. Then, the crystal of the zinc hydroxide compound was dried, and then calcined at 500 ° C. for 3 hours to proceed with the dehydration reaction of zinc hydroxide contained in the zinc hydroxide compound to obtain the zinc oxide crystal of Comparative Example 5. It was. This zinc oxide did not have a plate-like morphology. An electron micrograph of zinc oxide of Comparative Example 5 is shown in FIG.

The zinc oxide of Examples 1 to 9 was carried out within the range of the production conditions of the present invention, and was a plate-shaped zinc oxide having a total length of 5 to 50 μm and an aspect ratio of 6 to 100. In particular, the zinc oxides of Examples 1 to 7 in which zinc sulfate was used as the second raw material liquid had an appropriately large aspect ratio and were optimal as zinc compounds for cosmetics. Comparing the zinc oxides of Examples 1, 6 and 7, the electron micrographs (FIGS. 2, 7, and 8) show that the higher the firing temperature in the heat treatment step, the more the crystals become porous. It was confirmed that

On the other hand, in the zinc oxide of Comparative Example 1, since water was used as the starting raw material solution instead of the first raw material aqueous solution, the pH at the start of the reaction became low, so that crystal formation did not proceed sufficiently, and as a result, crystals were formed. The balance between formation and crystal growth was lost, and the aspect ratio became excessive. The zinc oxide of Comparative Example 2 had a high pH at the start of the reaction due to an excessive content of sodium hydroxide in the first aqueous solution, so that the crystal growth did not proceed sufficiently, and as a result, the zinc oxide was plate-shaped. Could not form crystals of. Similar to Comparative Example 1, the zinc oxide of Comparative Example 3 uses water instead of the first raw material aqueous solution as the starting raw material solution, but when a zinc chloride-containing solution is used as the second raw material aqueous solution, it has a plate shape. Crystals were not formed and amorphous particles were formed. In the zinc oxide of Comparative Example 4, the aqueous solution of the second raw material does not contain urea, but in this case, the pH change due to the dropping of the aqueous solution of the second raw material becomes excessive, so that the crystal growth does not proceed sufficiently. As a result, the balance between crystal formation and crystal growth was lost, and the aspect ratio became too small. The zinc oxide of Comparative Example 5 was obtained by dropping the second raw material aqueous solution at once without dropping it in two steps, but in this case, crystal formation and crystal growth did not proceed sufficiently, and as a result, the amorphous shape was formed. Particles were formed.

<Performance evaluation>
Using zinc oxide of Examples 1 to 9 and Comparative Examples 1 to 5, (1) usability and (2) solidification or gelation performance of fats and oils were evaluated. Each evaluation method will be described below.

(1) Usability When cosmetics (powder foundation) containing zinc oxide of Examples 1 to 9 and Comparative Examples 1 to 5 were prepared and each cosmetic was applied to the face with a puff, 10 panelists A sensory evaluation test was carried out. The sensory evaluation test was conducted in the form of a questionnaire, and an evaluation score of 0 to 5 was given for the overall usability such as slipperiness, adhesiveness, and makeup loss. 0 point was the worst usability, and 5 points. Was quantified as having the best usability, and the results were expressed as the average score of all panelists.

(2) Solidification or gelation performance of fats and oils 1 g of zinc oxide of Examples 1 to 9 and Comparative Examples 1 to 5 were mixed with 9 g of oleic acid as fats and oils to prepare a test sample. A confirmation test was conducted in which 1 g of each test sample was dropped onto a glass plate placed horizontally and the glass plate was shaken to visually judge the fluidity of the test sample. Then, the time from the start of the test to the time when the fluidity of the test sample decreased or disappeared was defined as the solidification or gelation time.

The evaluation results using zinc oxide of Examples 1 to 9 and Comparative Examples 1 to 5 are shown in Table 2 below.

The powder foundation containing zinc oxide of Examples 1 to 9 had an evaluation score of 4 points or more, and was evaluated as a cosmetic having an excellent usability as a whole. In addition, the solidification or gelation time of oleic acid by zinc oxide in Examples 1 to 9 is within the range of 2 to 10 minutes, which is convenient as a raw material for cosmetics, but also causes oil floating in cosmetics. It was able to prevent makeup from coming off.

On the other hand, the powder foundations containing zinc oxide of Comparative Examples 1 to 5 had a usability evaluation score of less than 4, which was not satisfactory as a cosmetic. Regarding the solidification or gelation time of oleic acid by zinc oxide in Comparative Examples 1 to 5, zinc oxide in Comparative Example 1 required a very long time of 120 minutes or more, and is not suitable as a raw material for cosmetics. there were. Zinc oxide in Comparative Examples 2 and 5 also took more than 10 minutes, and could not be said to be easy to use as a raw material for cosmetics.

The zinc compound for cosmetics of the present invention can be used as a raw material for cosmetics such as foundation, blusher, eye shadow, mascara, and eyeliner. In addition, the method for producing a zinc compound for cosmetics of the present invention can be used in the above-mentioned manufacturing industry for cosmetics.

Claims (9)

A plate-shaped zinc compound for cosmetics
A zinc compound for cosmetics having a total length of 5 to 50 μm and an aspect ratio of 6 to 100, which is the ratio of the total length to the thickness. When a fat / oil mixture having a content of 10% by weight or more is prepared by adding it to a fat / oil containing C _{16 to} C ₂₀ monounsaturated fatty acids, the fluidity of the fat / oil mixture is reduced or disappears in 2 to 10 minutes. The zinc compound for cosmetics according to claim 1, which is set in 1. A method for producing a plate-shaped zinc compound for cosmetics.
A preparatory step for preparing a first aqueous solution in which an alkali metal hydroxide is dissolved and a second aqueous solution in which a water-soluble zinc compound and a hydrolyzable alkalinable nitrogen-containing compound are dissolved, respectively.
A crystal generation step of dropping a part of the second raw material aqueous solution into the first raw material aqueous solution to form a seed crystal of a zinc hydroxide compound in the liquid.
A crystal growth step of dropping the remainder of the second raw material aqueous solution into a mixed solution containing seed crystals to grow crystals, and
A separation step of separating the crystals from the mixed solution containing the crystals,
A heat treatment step of drying and firing the separated crystals,
A method for producing a zinc compound for cosmetics, which comprises. In the preparatory step, the concentration of the alkali metal hydroxide in the first aqueous solution is adjusted to 0.1 to 0.7 mol / L, and the concentration of the water-soluble zinc compound in the second aqueous solution is 0.2. The method for producing a zinc compound for cosmetics according to claim 3, wherein the concentration of the hydrolyzable alkalinable nitrogen-containing compound is adjusted to 0.4 to 12 mol / L. The method for producing a zinc compound for cosmetics according to claim 3 or 4, wherein the crystal formation step is carried out until the hydrogen ion concentration (pH) of the mixed solution is reduced to 11 or less. The method for producing a zinc compound for cosmetics according to any one of claims 3 to 5, wherein the crystal forming step includes a first aging step of aging the produced seed crystal. The zinc compound for cosmetics according to any one of claims 3 to 6, wherein in the crystal formation step, the liquid temperature of the first raw material aqueous solution before dropping the second raw material aqueous solution is maintained at 70 to 95 ° C. Manufacturing method. The method for producing a zinc compound for cosmetics according to any one of claims 3 to 7, wherein the crystal growth step includes a second aging step of aging the grown crystals. The method for producing a zinc compound for cosmetics according to any one of claims 3 to 8, wherein the heat treatment step is carried out in a state where the crystals are crushed.