KR100740275B1 - Method for preparing of zinc oxide powder with nano size - Google Patents

Abstract

Provided is a method for preparing zinc oxide powder of nano-size for use in cosmetics, capable of preparing zinc oxide powder at high efficiency through a single-step wet process and markedly improving UV shielding effect, transparency, and skin adhesiveness. The preparation method of zinc oxide powder of nano-size comprises the steps of: preparing a mixture of a zinc compound, a sufficient amount of water for fully dissolving the zinc compound, and 10-100wt.% alcohol with respect to 100wt% water; adding an alkaline solution of 10-20wt.% concentration in form of liquid droplets having a maximum diameter of 100 micrometers or less to form zinc hydroxide through neutralization; oxidizing the zinc hydroxide obtained from the second step; dehydrating, drying and milling the oxide obtained from the third step.

Description

Manufacturing method of nano-sized zinc oxide powder {METHOD FOR PREPARING OF ZINC OXIDE POWDER WITH NANO SIZE}

1 is an electron micrograph (× 10,000) of zinc oxide powder having a size of 40 nm prepared according to one embodiment of the present invention, and zinc oxide powder prepared in Comparative Examples 1 and 2, respectively.

Figure 2 is a photograph measuring the turbidity of the zinc oxide powder prepared according to Example 5 of the present invention and the zinc oxide powder prepared in Comparative Examples 1 and 2.

The present invention relates to a method for producing a nano-sized zinc oxide powder, and more particularly, it is possible to manufacture a nano-sized zinc oxide powder in a single process without going through a firing step, very economical, transparency when applied to cosmetics The present invention relates to a method for preparing a nano-sized zinc oxide powder and a zinc oxide powder produced thereby, which can remarkably improve a skin texture and skin adhesion, a decrease in ultraviolet ray shielding effect.

Sunlight emitted from the sun's surface is divided into γ-rays, x-rays, ultraviolet rays, visible light, and infrared rays, depending on the wavelength. Ultraviolet rays are further subdivided into UV-A (320-400 nm), UV-B (290-320 nm) and UV-C (200-290 nm). Of these, 52% of visible light, 42% of infrared light, and about 6% of UV-A and UV-B reach the earth's surface.

It is widely known that ultraviolet rays in the sunlight are harmful to the human body, and many studies have been conducted on new countermeasures against them. UV rays are beneficial to the human body, such as the synthesis of vitamin D, treatment of skin diseases, and bactericidal effects, but also cause skin aging, immune system abnormalities, and skin cancer. The erythema of the skin is caused by UV-B of short wavelength, and UV-A of relatively long wavelength penetrates into the dermis layer of the skin and promotes skin aging. In addition, due to the destruction of the ozone layer due to pollution of the global environment, the concern about ultraviolet rays increases, so that the public's awareness of ultraviolet rays also increases, and various applications are being developed to block ultraviolet rays.

Currently, research on organic and inorganic systems is being conducted as a means to block ultraviolet rays. Organic sunscreens have increased the importance of inorganic sunscreens having excellent chemical and physical stability due to safety problems such as contact dermatitis and photoallergic. Currently, inorganic sunscreens include zinc oxide having excellent blocking effect in the UV-A region and titanium oxide having excellent blocking effect in the UV-B region. Since zinc oxide is advantageous in terms of dispersibility as compared to titanium oxide as a UV blocking agent, research on zinc oxide is currently becoming the mainstream. When the size of the zinc oxide particles is smaller than the wavelength of the visible light, the visible light may pass through the zinc oxide dispersion. In addition, as the size of the zinc oxide particles decreases, it effectively scatters and absorbs the absorbed ultraviolet rays. Therefore, it is advantageous to produce nanoscale zinc oxide particles having excellent dispersibility in terms of ultraviolet absorption and visible light transmittance.

Conventional zinc oxide particles have been mainly used in a gas phase process, that is, a method in which zinc metal is vaporized and then reacted with oxygen gas present in the air. However, in the case of the zinc oxide particles produced using the gas phase method, zinc metal that does not react with oxygen is present, and the zinc oxide particle size distribution formed cannot be controlled. When these unreacted metal zinc particles are present in applications such as cosmetics, paints, plastics, and the like, they react with air, moisture, and organic materials to generate unwanted gases. Unreacted metal zinc particles may also be added to the application to give a gray color.

Another preparation of zinc oxide particles is coprecipitation, that is, zinc compounds (zinc sulfide, zinc chloride, zinc acetate, etc.) are dissolved in water and precipitated in the form of zinc carbonate, followed by washing, filtering, and calcining to produce oxides. It is a way. However, this method causes a problem that the production efficiency is lowered at the time of production of the final product due to many manufacturing processes, and the calcination process or the firing process must be carried out during the production of the zinc oxide particles. There was a disadvantage of being longer.

Therefore, research into a method for efficiently producing nano-sized zinc oxide even with a simple and short process continues.

In order to solve the problems of the prior art as described above, the present invention provides a method for producing nano-sized zinc oxide powder that can efficiently produce nano-sized zinc oxide powder in a single process of a wet process without a calcination process or an annealing process and It is to provide a nano-sized zinc oxide powder prepared by this method.

Another object of the present invention is to prepare a nano-sized zinc oxide powder that can significantly improve the transparency, skin texture and skin adhesion, the reduction of UV shielding effect when applied to cosmetics having a nano-size and prepared by this method It is to provide a nano-sized zinc oxide powder.

Still another object of the present invention is to provide a cosmetic composition capable of significantly improving transparency, skin feel and skin adhesion, and a reduction in ultraviolet ray shielding effect.

In order to achieve the above object, the present invention provides a method for producing a nano-sized zinc oxide powder,

a) i) zinc compound;
Ii) water in an amount sufficient to dissolve the zinc compound; And
Iii) alcohol in a ratio of 10 to 100 parts by weight based on 100 parts by weight of water;
Preparing a reactant by mixing;

b) adding 10 to 20% by weight of an aqueous alkali solution at a concentration of 10 to 20% by weight in the form of droplets having a diameter of up to 100 μm and neutralizing the reactant of step a) to form zinc hydroxide;

c) oxidizing the zinc hydroxide formed in step b); And

d) dehydrating, drying, and grinding the oxide of step c)

It provides a method for producing a nano-sized zinc oxide powder comprising a.

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Hereinafter, the present invention will be described in detail.

The present inventors controlled the method of adding the alkaline aqueous solution in the reaction after neutralizing the zinc compound with caustic soda, and thus it is possible to efficiently produce nano-sized zinc oxide powder in a single process without a separate calcination or firing process. It was confirmed that the present invention was completed based on this.

The nano-sized zinc oxide powder of the present invention comprises the steps of preparing a reactant by mixing a zinc compound, water, and alcohol, adding an aqueous alkali solution diluted in the reactant of the step in the form of droplets having a diameter of up to 100 μm and Neutralizing to form zinc hydroxide, oxidizing the zinc hydroxide formed in the step, and dehydrating, drying, and pulverizing the oxide of the step.

Referring to the method for producing a nano-sized zinc oxide powder of the present invention in detail.

a) preparation of reactants

This step is to prepare a reactant by mixing the zinc compound, water, and alcohol.

The zinc compound is not particularly limited as long as it is in the form of a zinc salt that can be dissolved in water, and preferably zinc chloride, zinc nitrate, zinc sulfate, or the like can be used.

The alcohol may be a low-cost alcohol having 1 to 5 carbon atoms and the like, preferably ethanol, methanol, propanol, isopropyl alcohol and the like.

The mixing of the zinc compound, water, and alcohols is preferably such that there is no zinc compound remaining without dissolving using water enough to dissolve the mixed zinc compound, and the amount of alcohol used is 100 It is preferable to use 10 to 100 parts by weight, and more preferably 30 to 70 parts by weight based on parts by weight. At this time, the temperature may be adjusted to a maximum of 25 ℃ or less can be formed without zinc hydroxide during the neutralization in the subsequent step.

In the preparation of the reactant, 100 parts by weight of a silane such as alkyl silane, amino silane and epoxy silane having 1 to 20 carbon atoms or fatty acid such as silicone oil or stearic acid such as dimethicone, methicone, cyclomethicone, etc. The reactant may be prepared by further comprising 0.5 to 20 parts by weight with respect to. In this case, there is an advantage in that the zinc oxide powder coated up to a single wet process can be prepared.

b) neutralization (zinc hydroxide formation)

In this step, the aqueous alkali solution diluted in the reactant of the above step is introduced into a droplet having a diameter of up to 100 μm and neutralized to form zinc hydroxide.

The aqueous alkali solution is diluted in water and added to the reactant, and it is preferable to dilute in water so that the concentration of caustic soda is 20 wt% or less. When the concentration of the caustic soda exceeds 20% by weight, there is a problem that the particle size of the zinc hydroxide formed when neutralized by mixing into a large mass when added to the reactant becomes large. More preferably, in consideration of productivity and economy, it is preferable to use an aqueous solution of 10 to 15% by weight. The aqueous alkali solution of the present invention is not particularly limited as long as it dissolves a compound capable of forming a counter ion with a zinc compound in water, and preferably NaOH, KOH, Mg (OH) ₂ , Ca (OH) _2, or ammonia. It is good to dissolve in water.

The aqueous alkali solution diluted as described above is added to the reactant in the form of droplets having a diameter of up to 100 μm. The feeding method is not particularly limited, and as an example, a spray, aerosol, dropping method, or the like may be used. More preferably, it is preferably added in the form of droplets having a diameter of 80 μm or less. If the droplet size of the diluted aqueous alkali solution exceeds 100 μm, there is a problem that the particle size of the zinc oxide to be prepared is not manufactured to a nano size.

Dilute caustic soda containing an equivalent amount of caustic soda is used as the amount of the diluted aqueous alkali solution added to the reactant.

In addition, the caustic soda is added to the reactant as described above, and the stirring speed in the reaction tube into which the caustic soda is added is preferably at most 10 rpm, so that the zinc hydroxide particles are formed in a small state.

c) Oxidation

This step is to oxidize the zinc hydroxide formed in the step.

That is, the zinc hydroxide is a step of forming a nano-sized zinc oxide particles through the oxidation process, the oxidation reaction is carried out while raising the temperature to 130 ℃ after the addition of the aqueous alkali solution to the reactant in step b).

At this time, the oxidation reaction is carried out in a completely closed reaction tube, the pH of the oxidation reaction is preferably 5 to 9, the pressure is preferably 2 to 4 atm.

More preferably, the oxidation reaction is stirred at a rate of up to 10 rpm in the same manner as the neutralization step at a temperature of 50 ℃ or less, and at a temperature of 50 ℃ or more while stirring at a rate of at least 60 rpm or more while increasing the temperature to 130 ℃ Is carried out for 36 to 56 hours.

d) dehydration, drying, and grinding

This step is a step of dehydrating, drying, and pulverizing the oxide of the above step.

When the oxidation reaction is completed through step c), the mixture is cooled and a dehydration process is performed. It is preferable to cool the said cooling below 80 degreeC.

The dehydration process may be carried out in the same manner as the dehydration process carried out in the production of a normal zinc oxide, it is possible to remove the water, alcohols, and other salinity except for the powder through such a dehydration process.

After the dehydration process is completed as described above, the powder is dried through a drying process, wherein the drying process may use a hot air dryer, a vacuum dryer, etc. as a conventional dryer, but the moisture of the powder at a temperature of 125 ° C. or more using a vacuum dryer. It is good to carry out so that content is 2% or less.

After the drying process is completed, the powder is then pulverized, and the pulverization is performed by a ball mill, a triple roller, an ultrasonic crusher, a bead mill, and a motor mill (usually used in the pulverization process). A final nano-sized zinc oxide powder is prepared using a mill such as a motor mill, an atomizer, or an ultra high pressure mill.

The zinc oxide powder of the present invention prepared through the above steps is preferably 5 to 100 nm in size.

In addition, the present invention is the nano-sized zinc oxide powder prepared through the above step is after the silane or dimethicone, such as alkyl silane, amino silane, epoxy silane having 1 to 20 carbon atoms, methicone, cyclo methicone, etc. Fatty acid such as oil or stearic acid may be added to the zinc oxide powder simultaneously to coat the surface. The amount of the coating agent and the acid solution to be added may be appropriately adjusted by those skilled in the art according to the zinc oxide powder used, and as a specific example, 0.5 to 20 parts by weight may be used based on 100 parts by weight of the zinc compound. The addition of the coating agent and the acid solution is preferably carried out slowly for 1 to 10 hours, the pH of the solution during the surface coating is preferably 8 to 10, the temperature is preferably made at 50 to 100 ℃.

In another aspect, the present invention provides a 5 to 100 nm zinc oxide powder prepared as described above and a cosmetic composition to which the zinc oxide powder is applied, the cosmetic composition to which the nano-sized zinc oxide powder according to the present invention is applied, transparency, skin It can significantly improve the texture, skin adhesion and UV shielding effect, which makes it suitable for UV protection. Preferably, the cosmetic composition may contain 1 to 30% by weight of the zinc oxide powder.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

EXAMPLE

Example 1

After dissolving 300 g of zinc chloride in 1.2 liters of water, 500 ml of isopropyl alcohol was added to the reaction tube, and the mixture was sufficiently stirred at a temperature of 25 ° C. or lower.

Then, an equivalent amount of caustic soda such as zinc chloride was added to water, diluted to a concentration of 15% by weight, and then added to the reactant in the form of droplets having a diameter of up to 100 μm. Was adjusted to be up to 10 rpm.

Thereafter, after the caustic soda was added, the temperature was raised to 130 ° C. to perform an oxidation reaction. At this time, the aging was stirred at a speed of up to 10 rpm at a temperature of less than 50 ℃, at a temperature of 50 ℃ or more was carried out for 36 to 56 hours while stirring at a speed of at least 60 rpm or more.

After the oxidation reaction was completed, the water was cooled to 80 ℃ and dehydration process to remove water, alcohols, and other salts except the powder.

Then, using a vacuum dryer at 125 ℃ dried to a water content of 2% or less, and then ground using a bead mill to prepare a zinc oxide powder having a final average particle size of 80 nm size.

Example 2

After dissolving 300 g of zinc chloride in 1.2 liters of water, 600 ml of isopropyl alcohol was added to the reaction tube, and the mixture was sufficiently stirred at a temperature of 25 ° C or lower.

Then, water was added to the equivalent of caustic soda such as zinc chloride, diluted to a concentration of 15% by weight, and then added to the reactant in the form of droplets having a diameter of up to 80 μm, and the rate of the reaction tube at the time of addition. Was adjusted to be up to 10 rpm.

Thereafter, after the caustic soda was added, the temperature was raised to 130 ° C. to perform an oxidation reaction. At this time, the oxidation was stirred at a speed of up to 10 rpm at a temperature below 50 ℃, at a temperature of 50 ℃ or more was carried out for 36 to 56 hours while stirring at a speed of at least 60 rpm or more.

After the oxidation reaction was completed, the water was cooled to 80 ℃ and dehydration process to remove water, alcohols, and other salts except the powder.

Then, using a vacuum dryer at 125 ℃ dried to a moisture content of 2% or less, and then ground using a bead mill to prepare a zinc oxide powder having a final average particle size of 40 nm size.

Example 3

In Example 2, 300 g of zinc chloride was dissolved in 1.2 liters of water, and then, when 600 ml of isopropyl alcohol was added, 12 g of methicone was further added to the reaction solution to prepare zinc oxide powder. The final average particle size was 40 nm. It was confirmed that the zinc oxide powder surface-coated with silicone oil can be prepared by a single wet process.

Example 4

In Example 2, 300 g of zinc chloride was dissolved in 1.2 liters of water, and then, when 600 ml of isopropyl alcohol was added, 12 g of alkylsilane was further added to the reaction solution to prepare zinc oxide powder, and the final average particle size was 40 nm. It was confirmed that the zinc oxide powder surface-coated with alkylsilane can be prepared in a single wet process.

Example 5

11.6% by weight of zinc oxide powder prepared in Example 4, 45.1% by weight of water, 4.6% by weight of dipropylene glycol, 5.8% by weight of 1,3-butylene glycol, 0.6% by weight of magnesium sulfate, 0.2% by weight of methyl paraben, already 0.1% by weight of dazolidinyl urea (Germall-115), 0.6% by weight of D-panthenol, 3.5% by weight of hexyl laurate (Kak-HL), 12.6% by weight of cyclomethicone (KF-995), dimethicone 3.5% by weight of ticone and dimethicone crosslinked polymer (DC-9041), 1.2% by weight of dimethicone vinyldimethicone crosslinked polymer and dimethicone (KSG-16), 0.6% by weight of silica and dimethicone (Sunsil-130SC), methylmethacryl 0.6% by weight of crosslinked polymer (SunPMMA), 5.8% by weight of PEG-10 dimethicone (KF-6017), 2.3% by weight of cetyl PEG / PPG-10-1 dimethicone (Abil EM-90), quaternium-18 hexanes (quaternium-18 hectorite, Benton 38) A cosmetic was prepared by mixing 0.9% by weight, 0.1% by weight of propyl paraben, and 0.3% by weight of fragrance.

Comparative Example 1

Except for the zinc oxide powder of the present invention in Example 5, except for using a nano-sized (40nm) ZnO-303S (Tayca) surface treatment with methicone used in conventional cosmetics in the same manner as in Example 5 A cosmetic was prepared.

Comparative Example 2

A cosmetic was prepared in the same manner as in Example 5, except that Z-Cote HP-1 (BASF), which was surface-treated with an alkyl silane used in conventional cosmetics instead of the zinc oxide powder of the present invention, was used in Example 5 It was.

Comparative Example 3

Except for dropping the aqueous solution of caustic soda in Example 1 was dropped to the surface of the mixture so that the size of the droplet is 300 ㎛ was carried out in the same manner as in Example 1, but the size of the oxidized zinc oxide powder is 10 ㎛ or more Nanoscale zinc oxide could not be prepared.

Electron micrographs of the zinc oxide powders used in Examples 4 and Comparative Examples 1 to 2 are shown in FIG. 1.

Experiment

Using the zinc oxide powder of Examples 4 and Comparative Examples 1 and 2 to prepare a cosmetic according to the method of Example 5 to perform SPF, transparency, and sensory test, the preparation method in Table 1 the results are shown in Table 2 and Table 2 is shown.

No. Ingredients Contents INCI Name One water 45.1 water 2 DPG (odorless) 4.6 dipropylene glycol 3 1,3-BG 5.8 butylene glycol 4 Magnesium sulfate 0.6 magnesium sulfate 5 Methyl paraben 0.2 methyl paraben 6 Germall-115 0.1 imidazolidinyl urea 7 D-pantenol 0.6 panthenol 8 Kak-HL 3.5 hexyl laurate 9 KF-995 12.6 cyclomethicone 10 DC-9041 3.5 dimethicone and dimethicone cross polymer 11 KSG-16 1.2 dimethicone vinyldimethicone cross polymer and dimethicone 12 ZnO 11.6 Zinc oxide 13 Sunsil-130SC 0.6 silica and dimethicone 14 SunPMMA 0.6 methyl methacrylate cross polymer 15 KF-6017 5.8 PEG-10 dimethicone 16 Abil EM-90 2.3 cetyl PEG / PPG-10 / 1 dimethicone 17 Benton 38 0.9 quaternium-18 hectorite 18 Propyl paraben 0.1 propyl paraben 19 Fragrance 0.3 fragrance

TABLE 1 Cosmetic composition table according to Example 5 (unit is parts by weight)

First, the cosmetic composition having the same composition as in Example 5 was prepared and SPF was measured eight times using Optometirc 290, and the average value thereof was calculated. The SPF was increased per 1 g of ZnO used. In addition, the turbidity was measured using a NIPPON DENSHOKU COLOR METER ZE 2000 after the application of 0.1 g of the sample on the hiding rate paper and pushed with a baker applicator. In addition, the evaluation of the feeling of use was performed on 50 panelists, and the skin value, skin adhesion property, and ultraviolet ray shielding effect were evaluated on a 10-point scale twice, and the average value was shown.

division Example 5 Comparative Example 1 Comparative Example 2 1. SPF medium 16.0 12.9 10.0 SPF / g 1.4 1.1 0.9 2. Turbidity ^* 15.5 20.5 23.5  3. Feeling 1 time 9.5 7.0 5.0 Episode 2 9.0 8.0 7.5 medium 9.3 7.5 6.3

Whiteness ^* Lower whiteness is more transparent.

As shown in Table 2, the cosmetics using the nano-sized zinc oxide powder of the present invention of Example 5 prepared according to the present invention shows a large SPF / g of 30-50% or more compared to Comparative Examples 1 and 2 Could confirm. In addition, it was confirmed that the white turbidity was more transparent and showed significantly improved results compared to the comparative examples in the sensory evaluation.

The nano-sized zinc oxide powder according to the present invention has an effect of remarkably improving the transparency, skin texture and skin adhesion, and the reduction of UV shielding effect when applied to cosmetics by improving the size of the powder from the conventional micro size to the nano size. In particular, it is very economical by producing nano-sized zinc oxide powder finished to coating treatment in a single wet process without a calcination process or a calcination process.

Claims (6)

In the manufacturing method of nano-sized zinc oxide powder, a) i) zinc compound;   Ii) water in an amount sufficient to dissolve the zinc compound; And   Iii) alcohol in a ratio of 10 to 100 parts by weight based on 100 parts by weight of water; Preparing a reactant by mixing; b) adding 10 to 20% by weight of an aqueous alkali solution at a concentration of 10 to 20% by weight in the form of droplets having a diameter of up to 100 μm and neutralizing the reactant of step a) to form zinc hydroxide; c) oxidizing the zinc hydroxide formed in step b); And d) dehydrating, drying, and grinding the oxide of step c) Method for producing a nano-sized zinc oxide powder comprising a The method of claim 1, The mixed solvent is 100 parts by weight of water and 30 to 70 parts by weight of alcohol, characterized in that the nano-sized zinc oxide powder production method. The method of claim 1, The aqueous alkali solution of step b) is a method of producing a nano-sized zinc oxide powder, characterized in that the aqueous solution of caustic soda having an alkali concentration of 10 to 15% by weight. The method of claim 1, 100 parts by weight of a zinc compound containing at least one compound selected from the group consisting of alkyl silanes having 1 to 20 carbon atoms, aminosilanes, epoxy silanes, dimethicone, methicone, cyclomethicone, and stearic acid when preparing the reaction solution in step a) A method of simultaneously producing the nano-sized zinc oxide powder and surface coating, characterized in that it further comprises 0.5 to 20 parts by weight relative to the part. delete delete

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