WO2007123309A1

WO2007123309A1 - Mesoporous inorganic composite powder containing metal element in its structure and the method for manufacturing thereof

Info

Publication number: WO2007123309A1
Application number: PCT/KR2007/001568
Authority: WO
Inventors: Seung Hwan Yi; Sang Hoon Jeon; Se Jun Park; Sun Sang Kwon; Duck Hee Kim; Ih Seop Chang
Original assignee: Amorepacific Corporation
Priority date: 2006-04-20
Filing date: 2007-03-30
Publication date: 2007-11-01

Abstract

Disclosed are mosoporous inorganic composite powder, which is prepared through a simple process in an economic manner by partially substituting silica in the framework structure of mesoporous silica powder with a metal element, such as titanium or zinc, and at the same time, maintains structural uniformity similar to that of a mesoporous material consisting of a pure silica framework, as well as a preparation method thereof. Also disclosed is mesoporous inorganic composite powder, which is prepared by further loading metal oxides, such as cerium and iron, into the pores of said metal -substituted mesoporous inorganic composite powder, and thus has UV (UV-A and UV-B) blocking ability in a wide wavelength range and improved touch and safety, as well as a preparation method thereof.

Description

[DESCRIPTION]

[invention Title]

MESOPOROUS INORGANIC COMPOSITE POWDER CONTAINING METAL ELEMENT IN ITS STRUCTURE AND THE METHOD FOR MANUFACTURING THEREOF [Technical Field]

The present invention relates to mosoporous inorganic composite powder, which is prepared through a simple process in an economic manner by partially substituting silica in the framework structure of mesoporous silica powder with a metal element, such as titanium or zinc, and at the same time, maintains structural uniformity similar to that of a mesoporous material consisting of a pure silica framework, and to a preparation method thereof. Also, the present invention relates to mesoporous inorganic composite powder, which is prepared by further loading metal oxides, such as cerium and iron, into the pores of said metal element-substituted mesoporous inorganic composite powder, and thus has UV (UV-A and UV-B) blocking ability in a wide wavelength range and has improved touch and safety, and to a preparation method thereof . [Background Art]

Mesoporous silica powder is one of mesoporous molecular sieves. It is a mesoporous molecular sieve in which mesopores are regularly arranged. Since a new type of mesoporous molecular materials, designated as the M41S family, prepared using ionic surfactants as structural derivatives by researchers of Mobil Oil Corporation in the year 1991, were disclosed in US Patent Nos . 5,057,296 and 5,102,643, studies on such mesoporous molecular sieve materials have been actively conducted worldwide. Unlike the synthesis of existing molecular sieves, the mesoporous molecular sieves are synthesized via a liquid crystal templating mechanism and have an advantage in that the pore size thereof can be controlled to 2-50 nm by controlling either the kind of surfactant as a templating material or synthetic conditions during the synthetic process. US Patent Nos. 6,027,706 and 6,054,111 and Science, Vol. 279, pp 548, 1998 disclose mesoporous materials prepared using amphiphilic block copolymers as nonionic surfactants. In the case of zeolites, a single organic or inorganic molecule generally acts as a templating material for inducing a porous structure, whereas, in the case of mesoporous materials, a micelle structure consisting of an assembly of several surfactant molecules induces pores. It is generally known that surfactants consist generally of a hydrophilic head portion and a hydrophobic tail portion, and thus form various self-assembled micelle and liquid crystal structures in an aqueous solution. A hydrophilic portion located on the surface of such micelle or liquid crystal structures interact with an inorganic precursor to form an organic/inorganic nano-composite, and the removal of a surfactant from the nano-composite can provide a mesoporous material .

Unlike microporous materials having a pore size of less than 1.5 nm, such as existing zeolites or AlPO-based materials, the pore size of mesoporous materials can be increased to the range of mesopores (2-50 nm) . Thus, it became possible to apply molecular sieve materials in fields in which the application of the molecular sieve materials has been limited. For example, such molecular sieve materials having increased pore size can be applied in catalytic conversion reactions and for the adsorption and separation of molecules having a size larger than the pore size of microporous materials. Such mesoporous materials having regular pores have a very large surface area (>700 m²/g) , leading to an excellent capability to adsorb atoms or molecules. Also, they have a constant pore size, and thus are applied as carriers for catalytically active materials, such as transition metal compounds and amine oxides. In addition, the mesoporous materials are expected to be applied as conductive materials, optical display materials, chemical sensors, powders for fine chemical and biological applications, insulation materials having new mechanical and thermal properties, and packaging materials and can be used in many applications.

However, because mesoporous inorganic composite powder consisting of a pure silica framework does not have other characteristics, including ion exchange capability or UV-blocking effects, there is a limitation in applying the mesoporous inorganic composite powder in cosmetic applications. This limitation can be solved by substituting other metal elements into the framework. However, if metals are added during a process for preparing molecular sieves, the prepared mesoporous silica powder will show a decrease in the structural uniformity thereof, compared to the pure silica powder. For example, in the case of MCM-41 having a Si/Al ratio of less than 30, the structure thereof is clearly degraded (Luan et al . , Journal of Physical Chemistry, vol. 99, pp. 1018-1024, 1995). In an attempt to overcome this shortcoming, Korean Patent Registration No. 0502449 discloses a post-treatment method of substituting metals into a framework structure regardless of the kind of mesoporous inorganic composite powder while maintaining the structural uniformity of the powder. However, this is a method of substituting metals into a molecular sieve material having a completely synthesized silica framework structure using metal precursors and a suitable organic solvent, and comprises substituting metals into the silica framework after forming the silica framework. Thus, this method requires a complicated preparation process and has low economic efficiency, and thus there is a limitation on the application thereof.

Accordingly, there is a need to develop a preparation method, which maintains the structural uniformity of mesoporous material and, at the same time, employs a simpler process, which results in an increase in economic efficiency.

Meanwhile, skin aging is closely connected with the increase, drooping and relaxation of wrinkles. As the causes of such phenomena, natural physiological aging, and aging events caused by environmental factors, including UV- light exposure, are mentioned. Particularly, skin aging connected with cosmetic products is generally caused by continuous exposure to UV light, and for this reason, deep wrinkles are formed, the skin droops, and non-uniform spots are produced, thus impairing the appearance of the skin. Histologically examining such phenomena, the epidermis becomes thin due to the continuous exposure of the skin to UV light, the thickness of the dermis also decreases, and elastin that is the main component of elastic fibers present on the skin is severely deformed, so that elastotic material formed of macromolecules is accumulated in the upper and middle layer of the dermis . The elastotic material impairs the normal function of elastic fibers, and thus causes a wrinkled skin lacking elasticity, in addition to the loss of collagen caused by the activity of matrix metalloproteinases (MMPs) .

Accordingly, studies on cosmetic compositions for reducing or delaying the above-described skin aging phenomena have been conducted, and include a method of reducing the skin penetration of UV radiation using UV- blocking agents. Also, many studies on UV-blocking compounds for protecting the skin from UV radiations (UV-A and UV-B) have been conducted. However, organic UV- blocking agents show a problems in terms of optical stability when they are used in cosmetic compositions. Also, they are absorbed into the skin to cause skin irritation, or they cause a serious problem in terms of safety due to photoreaction products. For this reason, most of the organic UV-blocking agents have limitations in use .

Meanwhile, the use of inorganic UV-blocking agents can provide UV-blocking agents, which block UV light in a wide wavelength range and, at the same time, cause no irritation to skin. The inorganic UV-blocking agents have a shortcoming in an aesthetic point of view, in that they look white when they are applied on the skin. Also, they have shortcomings in that the UV-blocking ability thereof is lower than that of the organic UV-blocking agents, they can result in skin irritation and skin injury due to optical activity caused by free radicals, and the particle size thereof is increased due to the secondary aggregation of particles, so that the UV-blocking ability thereof decreases with the passage of time.

An ideal UV-blocking agent should be nontoxic to skin tissue, should not irritate the skin, should have resistance to chemical decomposition and photolysis when it is applied as a cosmetic product, and should not be absorbed into the skin. Thus, there is a need to develop an inorganic UV-blocking agent, which shows a high ability to block UV light in a wide wavelength range and has excellent safety to the skin. [Disclosure] [Technical Problem]

Accordingly, the present inventors have found that by partially substituting silica in the framework structure of mesoporous silica powder with metal elements, such as titanium and zinc, mesoporous inorganic composite powder can be prepared through a more simplified process in an economic manner while maintaining structural uniformity similar to that of a mesoporous material consisting of a pure silica framework, thereby completing the present invention.

Also, the present inventors have found that by further loading metal oxides, such as cerium and iron oxides, into said mesoporous inorganic composite powder, it is possible to provide mesoporous inorganic composite powder, which has UV (UV-A and UV-B) -blocking ability in a wide wavelength range and has improved touch and safety, thereby completing the present invention.

Accordingly, it is an object of the present invention to provide mesoporous inorganic composite powder prepared by partially substituting silica in the framework structure of mesoporous silica powder with a metal element, such as titanium or zinc, as well as a preparation method thereof.

Another object of the present invention is to provide mesoporous inorganic composite powder prepared by further loading metal oxides (e.g., cerium oxide, iron oxide, etc.) into said metal element-substituted mesoporous inorganic composite powder, as well as a preparation method thereof.

[Description of Drawings]

FIG. 1 is a schematic diagram of the structure of mesoporous silica materials prepared in Examples 1 to 3 , in which titanium is substituted into the framework of the silica materials.

FIG. 2 is an X-ray diffraction graph of derivative mesoporous silica composites prepared in Reference Example 2 and Example 1, in which titanium is substituted into the framework of the composites.

FIG. 3 is a scanning electron microscope photograph of mesoporous silica powder prepared in Example 2, in which titanium is substituted into the framework of the powder.

FIG. 4 is an energy dispersive X-ray (EDX) graph of mesoporous silica powder prepared in Example 1, in which titanium is substituted into the framework of the powder.

FIG. 5 is a schematic diagram of the structure of mesoporous inorganic composite powders prepared in Examples 4 and 5.

FIG. 6 is an X-ray diffraction graph of mesoporous inorganic composite powder prepared in Examples 1 and 4.

FIG. 7 is a graph showing an adsorption-desorption isotherm calculated at liquid nitrogen temperature for mesoporous inorganic composite powder prepared in Example 4. FIG. 8 is an energy dispersive X-ray (EDX) graph of mesoporous silica powder prepared in Example 4.

FIG. 9 shows UV spectra of mesoporous inorganic composite silica prepared in Examples 1 and 4, in which titanium is substituted into the framework of the powder, and mesoporous inorganic composite powders, in which cerium and iron are loaded in the pores of the titanium- substituted mesoporous silica.

[Best Mode] To achieve the above objects, the present invention provides mesoporous inorganic composite powder, in which silica in the framework structure of mesoporous silica powder is partially substituted with a metal atom such as titanium or zinc, as well as a preparation method thereof. The metal element substituted into the framework structure is preferably at least one selected from the group consisting of titanium (Ti) and zinc (Zn) .

The method for preparing mesoporous inorganic composite powder according to the present invention comprises the steps of:

(A) dissolving a surfactant in distilled water, and dissolving a metal precursor in an acid, and mixing the solutions with each other; (B) adding a silica precursor to the mixture obtained in the step (A) , adjusting the silica precursor-containing material to a neutral pH, and subjecting the pH-adjusted material to a hydrothermal reaction;

(C) filtering, washing and drying the material obtained in the step (B) ; and

(D) calcining the material obtained in the step (C) to remove the surfactant .

Hereinafter, each of the preparation method according to the present invention will be described in further detail.

In the step (A) of the method according to the present invention, a surfactant is dissolved in distilled water, a metal precursor is dissolved in an acid solution, and then the two solutions are mixed with each other. When the surfactant is mixed with distilled water, it acts as a templating material to form a self-assembled molecular structure at a suitable concentration. Herein, the amount of surfactant added is preferably 0.005-0.02 moles, and more preferably 0.01-0.02 moles, based on one mole of silica.

Preferred examples of the surfactant used in the step (A) include cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, polyethylene glycol dodecyl ether, polyoxyethylene (23) lauryl ether, polyoxyethylene (2) cetyl ether, polyoxyethylene (10) cetyl ether, polyethylene glycol hexadecyl ether, polyoxyethylene (10) stearyl ether, polyoxyethylene glycoloctadecylether and poly (ethylene glycol) -block- poly (propylene glycol) -block-poly (ethylene glycol) . More preferred is poly (ethylene oxide) -block-poly (propylene oxide) -block-poly (ethylene oxide) .

The metal precursor used in the step (A) is preferably a compound which can be dissolved in acids, such as acetic acid, hydrochloric acid and sulfuric acid, and specific examples thereof may include titanium alkoxides, such as titanium isopropoxide and titanium butoxide, titanium sulfate, titanium tetrachloride (TiCl₄) , zinc tetrachloride (ZnCl₄) and zinc acetate.

In the step (B) of the preparation method according to the present invention, the mixture obtained in the step (A) is adjusted to a neutral pH using a silica precursor, and then subjected to a hydrothermal reaction.

Preferred examples of the silica precursor used in the step (B) may include tetraethylorthosilicate (TEOS) , tetramethylorthosilicate (TMOS) , methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, methyltrichlorosilane , dimethyldichlorosilane , trimethylchlorosilane, bis (trichlorosilyl) methane, 1,2- bis (trichlorosilyl) ethane, bis (trimethoxysilyl) methane, 1, 2-bis (triethoxysilyl) ethane and sodium metasilicate . More preferred is colloidal silica (Ludox HS-40, Dupont) .

The silica precursor is preferably added slowly to the mixture solution obtained in the step (A) , while it is intensively stirred with a stirrer at room temperature. Herein, the amount of silica precursor added is preferably 1-100 moles, and more preferably 10-50 moles, based on one mole of the surfactant. Then, the mixture is subjected to a hydrothermal reaction at 30-50 ^°C to synthesize mesoporous inorganic composite powder.

Specifically, the surfactant in the step (A) forms a micelle structure in the aqueous solution through a self- assembly phenomenon. On the micelles thus formed, the silica precursor reacts to form an oligomer, which is then polymerized. The reaction time is 1-144 hours, and preferably 12-48 hours.

In the step (C) of the preparation method according to the present invention, the above- formed material is filtered, washed and then dried. Specifically, the material is washed 2-5 times with ethanol and dried at 50-

200 ^°C for 3-30 hours.

In the step (D) of the preparation method according to the present invention, the material obtained in the step

(C) is calcined. Specifically, the material is calcined at 400-600 ^°C for 18 minutes to 30 hours to remove the surfactant as a templating material, thus preparing mesoporous inorganic composite powder having the metal element substituted thereinto.

The inventive mesoporous inorganic composite powder prepared according to the above-described method is characterized in that the weight ratio of silica in the framework to the substituted metal element is 5:1 to 20:1.

Also, the mesoporous inorganic composite powder, which is prepared according to the above-described method, maintains the uniformity of a mesoporous structure and, at the same time, can be prepared in a simpler process, which has increased economic efficiency.

In another aspect, the present invention provides mesoporous inorganic composite powder, in which a metal oxide such as cerium oxide or iron oxide is further loaded in the pores of the above-described mesoporous inorganic composite powder, as well as a preparation method thereof.

The metal oxide loaded in the pores is preferably at least one selected from the group consisting of cerium oxide, iron oxide, titanium oxide and zinc oxide.

The method for preparing mesoporous inorganic composite powder according to the present invention comprises the steps of: (A) dissolving a surfactant in distilled water, and dissolving a metal precursor in an acid, and mixing the solutions with each other;

(B) adding a silica precursor to the mixture obtained in the step (A) , adjusting the silica precursor-containing material to a neutral pH, and subjecting the pH-adjusted material to a hydrothermal reaction;

(C) filtering, washing and drying the material obtained in the step (B) ;

(D) calcining the material obtained in the step (C) to remove the surfactant;

(E) dissolving a metal precursor in distilled water or alcohol;

(F) mixing the material obtained in the step (D) with the metal precursor solution obtained in the step (E) ; and (G) drying and then calcining the material obtained in the step (F) .

Hereinafter, each step of the preparation method according to the present invention will be described in further detail. The mesoporous inorganic composite powder according to the present invention is characterized in that it is prepared through the steps (E) to (G) of further loading a metal oxide (such as cerium oxide or iron oxide) into the pores of the mesoporous inorganic composite powder prepared through the steps (A) to (D) . That is, the steps (A) to (D) are the same as those of the above-described method for preparing mesoporous inorganic composite powder.

In the step (E) , in order to load a metal oxide into the pores of a mesoporous silica molecular sieve, a metal precursor is dissolved in distilled water or alcohol. Herein, the amount of metal precursor added is preferably 0.001-0.01 moles, and preferably 0.001-0.005 moles, based on one mole of silica.

The metal precursor used in the step (E) is preferably a compound which can be dissolved in solvents, such as distilled water, alcohol or acetonitrile, and specific examples thereof may include cerium chloride, cerium nitrate, iron chloride, iron nitrate, metal alkoxides, such as titanium isopropoxide and titanium butoxide, titanium sulfate, titanium tetrachloride (TiCl₄) , zinc tetrachloride (ZnCl₄) and zinc acetate.

In the step (F) of the preparation method according to the present invention, the metal precursor solution obtained in the step (E) is mixed with the mesoporous molecular sieve obtained in the step (D) , using an incipient wetness method at room temperature. Herein, the mesoporous molecular sieve to the metal precursor solution are preferably mixed at a weight ratio of 1:1-1.3, and more preferably 1:1. Thereafter, in the step (G) of the preparation method according to the present invention, the material obtained in the step (F) is dried at 50-200 ^°C for 3-30 hours, and then calcined at 400-600 ^°C for 0.3-30 hours to oxidize the metal precursor loaded in the pores, thereby preparing mesoporous inorganic composite powder having UV-blocking ability.

In addition to the above method, any method known in the art can be used to prepare mesoporous inorganic composite powder unless it impairs the object of the present invention.

Furthermore, such mesoporous inorganic composite powder can be formulated in various forms , and thus can be used particularly as cosmetics . [Mode for Invention] Hereinafter, the present invention will be descried in further detail with reference to examples. It will however be obvious to one skilled in the art that these examples are illustrative only and the scope of the present invention is not limited thereto. Reference Example 1

Mesoporous silica powder was prepared in the same manner as described in Korean Patent Laid-Open Publication No. 2006-0129824 (December 18, 2006) and Korean Patent Application No. 2005-0094794. Specifically, 20 g of poly (ethylene glycol) -block- poly (propylene glycol) -block-poly (ethylene glycol) was dissolved in 602.57 g of 2N sulfuric acid. Then, 43.11 g of tetraethylorthosilicate was added thereto, while the solution was intensively stirred with a magnetic stirrer at room temperature. After the reaction mixture was stirred at room temperature for 1 hour, the solution was stirred at

40 "C for 24 hours. Then, the reaction mixture was subjected to a hydrothermal reaction in an oven at 100 ^°C for 24 hours. The formed precipitate was filtered and then dried at 100 ^°C . In order to remove the surfactant remaining in the dried material, the dried material was washed clean with ethanol and calcined in air at 650 ^°C for 10 hours. Reference Example 2

Mesoporous molecular sieve MSU-H was prepared using a method, comprising an improvement made by the present inventors on the basis of the disclosure of Bagashaw et al . , Science, vol. 169, pp. 1242, 1995. The preparation method was carried out in the following manner.

16.4 g of NaOH (98%) was dissolved in 58.36 g of distilled water to prepare solution A. Herein, NaOH was sufficiently dissolved in the water bath at about 80 ^°C . To the solution A, 25 g of Ludox HS-40 (colloidal silica, DuPont) was added. The temperature of the water bath continued to be maintained at 80 ^°C , and when the solution changed from a white color to a transparent color, the heating of the solution was stopped. 16.41 g of poly (ethylene glycol) -block-poly (propylene glycol) -block- poly (ethylene glycol) was dissolved in distilled water to prepare solution B. Then, the solution B was intensively stirred with a magnetic stirrer at room temperature, while the solution was added thereto. After the reaction mixture was stirred at room temperature for 5-10 minutes, it was adjusted to a neutral pH with an acetic acid solution. Then, the solution was stirred at 40 "C for 24 hours. The formed precipitate was filtered and dried at 100 ^°C . In order to remove the surfactant remaining in the dried material, the dried material was washed clean with ethanol and calcined in air at 650 ^°C for 10 hours.

Example 1: Preparation (1) of mesoporous inorganic composite powder substituted with metal atom

24.98 g of acetic acid (99.5%) was mixed with 17.70 g of titanium isopropoxide to prepare solution A. 16.4 g of NaOH (98%) was dissolved in 58.36 g of distilled water to prepare solution B. Herein, NaOH was sufficiently dissolved in the water bath at about 80 ^°C . To the solution B, 25 g of colloidal silica (Ludox HS-40, DuPont) was added. The temperature of the water bath continued to be maintained at 80 ^°C , and when the solution changed from a white color to a transparent color, the heating of the solution was stopped.

16.41 g of poly (ethylene oxide) -block-poly (propylene oxide) -block-poly (ethylene oxide) was dissolved in distilled water to prepare solution C. Then, the solution C was intensively stirred with a magnetic stirrer at room temperature, while the solution A was added thereto. After the reaction mixture was stirred at room temperature for 5 minutes, it was adjusted to a neutral pH using the solution B, and then stirred at room temperature for 1 hour. The solution was stirred at 40 ^°C for 20 hours, and the formed precipitate was filtered, washed two times with distilled water, and then dried at room temperature. In order to remove the surfactant remaining in the dried material, the dried material was washed clean with ethanol and calcined in air at 650 ^°C for 10 hours.

Example 2: Preparation (2) of mesoporous inorganic composite powder substituted with metal atom

24.98 g of acetic acid (99.5%) was mixed with 14.78 g of titanium butoxide to prepare solution A. 16.4 g of NaOH

(98%) was dissolved in 58.36 g of distilled water to prepare solution B. Herein, NaOH was sufficiently dissolved in the water bath at about 80 ^°C . To the solution B, 25 g of colloidal silica (Ludox HS-40, DuPont) was added. The temperature of the water bath continued to be maintained at 80 ^°C , and when the solution changed from a white color to a transparent color, the heating of the solution was stopped.

Example 3: Preparation (3) of mesoporous inorganic composite powder substituted with metal atom

21.76 g of acetic acid (99.5%) was mixed with 8.318 g of titanium sulfate to prepare solution A. 16.4 g of NaOH (98%) was dissolved in 58.36 g of distilled water to prepare solution B. Herein, NaOH was sufficiently dissolved in the water bath at about 80 ^°C . To the solution B, 25 g of colloidal silica (Ludox HS-40, DuPont) was added. The temperature of the water bath continued to be maintained at 80 ^°C , and when the solution changed from a white color to a transparent color, the heating of the solution was stopped.

16.41 g of poly (ethylene oxide) -block-poly (propylene oxide) -block-poly (ethylene oxide) was dissolved in distilled water to prepare solution C. Then, the solution C was intensively stirred with a magnetic stirrer at room temperature, while the solution A was added thereto. After the reaction mixture was stirred at room temperature for 5 minutes, it was adjusted to a neutral pH using the solution B, and then stirred at room temperature for 1 hour. The solution was stirred at 40 "C for 20 hours, and the formed precipitate was filtered, washed two times with distilled water, and then dried at room temperature. In order to remove the surfactant remaining in the dried material, the dried material was washed clean with ethanol and calcined in air at 650 ^°C for 10 hours.

Meanwhile, a schematic diagram of the structure of the mesoporous inorganic composite powders prepared in Examples 1 to 3 is shown in FIG. 1.

Also, X-ray diffraction graphs of the mesoporous silica materials prepared in Reference Example 1 and Example 1 are shown in FIG. 2. As can be seen in FIG. 2, the X-ray diffraction graphs of Reference Example 1 and Example 1 are the same, suggesting that the mesoporous inorganic composite powder according to the present invention maintained the structural uniformity of the prior silica powder without changes.

FIG. 3 shows a scanning electron microscope photograph of the mesoporous inorganic composite powder prepared in Example 2. As can be seen in FIG. 3, even when a metal element was substituted into the framework structure of mesoporous inorganic composite powder according to the preparation method of the present invention, mesoporous silica having a uniform shape and size could be obtained.

FIG. 4 is an energy dispersive X-ray graph of the mesoporous composite powder prepared in Example 1. It could be seen that titanium was detected in the graph of FIG. 4, suggesting that titanium was substituted into the silica framework structure through the preparation method according to the present invention.

Example 4: Preparation (1) of mesoporous inorganic composite powder loaded with metal oxides 15 g of cerium chloride was completely dissolved in

10 g of distilled water. Then, 10 g of the mesoporous inorganic composite powder prepared in Example 1 was mixed with the cerium precursor solution at room temperature, and the mixture was stirred for 1-3 hours, filtered, dried in a vacuum at room temperature and calcined, thus obtaining 16 g of mesoporous composite powder loaded with cerium oxide

(A) . 5.8 g of iron chloride was completely dissolved in 5 g of distilled water, and then the mesoporous composite powder loaded with cerium oxide (A) was mixed with the iron precursor solution. Then, the mixture was stirred for 1-3 hours, filtered, dried in a vacuum at room temperature and calcined, thus obtaining 17.5 g of mesoporous inorganic composite powder loaded with cerium oxide and iron oxide. Example 5: Preparation (2) of mesoporous inorganic composite powder loaded with metal oxides

18.6 g of cerium nitrate was completely dissolved in 10 g of distilled water. Then, 10 g of the mesoporous inorganic composite powder prepared in Example 1 was mixed with the cerium precursor solution at room temperature, and the mixture was stirred for 1-3 hours, filtered, dried in a vacuum at room temperature and calcined, thus obtaining 16 g of mesoporous composite powder loaded with cerium oxide

(A) . 7.2 g of iron nitrate was completely dissolved in 5 g of distilled water, and then the mesoporous composite powder loaded with cerium oxide (A) was mixed with the iron precursor solution. Then, the mixture was stirred for 1-3 hours, filtered, dried in a vacuum at room temperature and calcined, thus obtaining 17.5 g of mesoporous inorganic composite powder loaded with cerium oxide and iron oxide. Test Example 1: Safety of mesoporous inorganic composite powder loaded with metal oxides

Because the raw material of cosmetics is used in the human body, its safety to the human body is particularly important. Thus, whether the mesoporous inorganic composite powders (UV-blocking compounds) prepared in

Examples 4 and 5 are toxic and irritant to the human body was examined through the following tests. Herein, the safety test was performed using a solution made by dispersing each of the mesoporous inorganic composite powers of Examples 4 and 5 in PEG-400 oil at a concentration of 30%.

1) Primary skin irritation test

For a primary skin irritation test, the back of each of 12 NZ white rabbits (Hallym Experimental Animal Center,

Korea) was shaved 24 hours before the test materials were applied. 0.1 ml of each of the mesoporous inorganic composite powders prepared in Examples 4 and 5 was applied on an area of 2.5 cm x 2.5 cm in the shaved back for 24 hours. Then, the applied area was observed.

As a result, it was observed that the mesoporous inorganic composite powders were not irritant.

2) Skin sensitization test

For a skin sensitization test, 6 Guinea pigs (3 males and 3 females) were subjected to the Magnusson and Kligman test using each of the mesoporous inorganic composite powders prepared in Examples 4 and 5.

As a result, abnormal skin conditions, including erythema, edema and eschar formation, could not be observed. 3) Human patch test Thirty 20 -28 -year-old healthy persons were subjected to a human patch test using each of the mesoporous inorganic composite powders of Examples 4 and 5 according to the CTFA guideline (The Cosmetic Toiletry and Fragrance Association, INC, Washington, D. C, 20036, 1991).

As a result, a primary skin irritation response did not appear.

From the toxicity and skin safety tests, it could be proven that the mesoporous inorganic composite powders of Examples 4 and 5 are non-toxic and non-irritant materials for use in cosmetics, that is, safe materials for skin external application.

Meanwhile, a schematic diagram of the structure of the mesoporous inorganic composite powders prepared in Examples 4 and 5 is shown in FIG. 5.

Also, X-ray diffraction graphs (Rigaku) of the mesoporous inorganic composite powders prepared in Examples 1 and 4 are shown in FIG. 6. As can be seen in FIG. 6, the mesoporous inorganic composite powder of Example 4, which has metal oxides loaded in the pores thereof, maintained its structural uniformity compared to the mesoporous inorganic composite powder of Example 1, substituted with the metal element. The resolution of the graph of the powder of Example 4 was reduced, but this reduction is believed to be attributable to a large amount of metal oxides loaded in the pores .

FIG. 7 is a graph showing an adsorption-desorption isotherm (Quantachrome) calculated at liquid nitrogen temperature for the mesoporous inorganic composite powder prepared in Example 4. From FIG. 7, it could be seen that the overall pore volume and specific surface area of the mesoporous inorganic composite powder of Example 4 were reduced, because the metal oxides were loaded in the pores of the molecular sieve substituted with the metal element. FIG. 8 shows an energy dispersive X-ray (EDX, Oxford) graph of the mesoporous inorganic composite powder prepared in Example 4. It could be seen that titanium (Ti), cerium (Ce) , iron (Fe) and silica (Si) were detected in the graph of FIG. 8, suggesting that cerium (Ce), iron (Fe) and titanium (Ti) were loaded in the mesoporous inorganic composite powder according to the preparation method of the present invention.

Test Example 2 : Examination of UV-blocking ability One of characteristics, which are required to practically apply the mesoposous inorganic composite powder of the present invention in cosmetics, is UV-blocking ability. Thus, in order to examine the UV-blocking abilities of the mesoporous silica powder (SiO₂) prepared in Reference Example 1 and the mesoporous inorganic composite powders prepared in Example 1 (TiSiO₂) and Example 4 (CeFe/Ti SiO₂) , UV spectra of these powders were measured. The measurement results are shown in FIG. 9.

From the results in FIG. 9, it could be seen that, in the case of Example 1 substituted with titanium, the absorption spectrum thereof was shifted toward UV-A, and the absorbance thereof was also increased compared to Reference Example 1. Moreover, in the case of the mesoporous inorganic composite powder of Example 4, loaded with the metal oxides, the absorption spectrum thereof was shifted toward UV-A and UV-B, suggesting that the powder of Example 4 had the ability to block both UV-A and UV-B.

From such results, it could be found that the mesoporous inorganic composite powder according to the present invention can be used to block UV radiations. Thus, when cosmetics contain the mesoporous inorganic composite powder of the present invention, the cosmetics will have UV-blocking and UV-scattering effects, [industrial Applicability]

As described above, according to the present invention, silica in the framework structure of mesoporous silica powder is partially substituted with a metal element such as titanium or zinc. By doing so, it is possible to prepare mesoporous inorganic composite powder through a more simplified process in an economic manner while maintaining structural uniformity similar to that of a mesoporous material consisting of a pure silica framework. This mesoporous inorganic composite powder is particularly useful in cosmetics .

Also, according to the present invention, metal oxides are further loaded in the pores of said mesoporous inorganic composite powder. By doing so, it is possible to prepare mesoporous inorganic composite powder, which has UV

(UV-A and UV-B) -blocking ability in a wide wavelength range and has improved touch and safety. Cosmetic compositions containing such mesoporous inorganic composite powder can be advantageously used to block UV radiation.

Claims

[CLAIMS]

[Claim l]

A mesoporous inorganic composite powder prepared by partially substituting silica in the framework structure of mesoporous silica powder with a metal element. [Claim 2]

The mesoporous inorganic composite powder of Claim 1, wherein the metal element is at least one metal selected from the group consisting of titanium and zinc. [Claim 3]

The mesoporous inorganic composite powder of Claim 1, wherein the weight ratio of the silica in the framework structure to the substituted metal element is 5:1 to 20:1.

[Claim 4] A mesoporous inorganic composite powder prepared by loading a metal oxide into the pores of a mesoporous inorganic powder prepared by partially substituting silica in the framework structure of mesoporous silica powder with a metal element . [Claim 5]

The mesoporous inorganic composite powder of Claim 4, wherein the metal oxide is at least one selected from the group consisting of cerium oxide, iron oxide, titanium oxide and zinc oxide. [Claim 6]

The mesoporous inorganic composite powder of any one of Claims 1 to 5 , which is used in cosmetics. [Claim 7] The mesoporous inorganic composite powder of any one of Claims 1 to 5 , which is used to block UV radiation. [Claim 8]

A method for preparing mesoporous inorganic composite powder, the method comprising the steps of:

(A) dissolving a surfactant in distilled water, and dissolving a metal precursor in an acid, and mixing the solutions with each other;

(C) filtering, washing and drying the material obtained in the step (B) ; and (D) calcining the material obtained in the step (C) to remove the surfactant . [Claim 9]

The method of Claim 8, wherein the surfactant used in the step (A) is selected from the group consisting of cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, polyethylene glycol dodecyl ether, polyoxyethylene (23) lauryl ether, polyoxyethylene (2) cetyl ether, polyoxyethylene (10) cetyl ether, polyethylene glycol hexadecyl ether, polyoxyethylene (10) stearyl ether, polyoxyethylene glycoloctadecylether and poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol) . [Claim 10]

The method of Claim 8, wherein the metal precursor used in the step (A) is at least one selected from the group consisting of titanium alkoxide, titanium sulfate, titanium tetrachloride (TiCl₄) , zinc tetrachloride (ZnCl₄) and zinc acetate. [Claim ll]

The method of Claim 10, wherein the titanium alkoxide is titanium isopropoxide or titanium butoxide. [Claim 12]

The method of Claim 8, wherein the acid used in the step (A) is selected from the group consisting of acetic acid, hydrochloric acid and sulfuric acid. [Claim 13]

The method of Claim 8, wherein the silica precursor used in the step (B) is at least one selected from the group consisting of tetraethylorthosilicate, tetramethylorthosilicate, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, bis (trichlorosilyl) methane, 1,2- bis (trichlorosilyl) ethane, bis (trimethoxysilyl) methane,

1, 2-bis (triethoxysilyl) ethane and sodium metasilicate.

[Claim 14]

The method of Claim 8, which further comprises the steps of :

(E) dissolving a metal precursor in distilled water or alcohol;

(F) mixing the material obtained in the step (D) with the metal precursor solution obtained in the step (E) ; and (G) drying and then calcining the material obtained in the step (F) . [Claim 15]

The method of Claim 14, wherein the metal precursor used in the step (E) is one or more selected from the group consisting of cerium chloride, cerium nitrate, iron chloride, iron nitrate, titanium isopropoxide, titanium butoxide, titanium sulfate, titanium tetrachloride (TiCl₄) , zinc tetrachloride (ZnCl₄) and zinc acetate. [Claim 16]

The method of Claim 14, wherein, in the step (F), the mesoporous molecular sieve of step (D) and the metal precursor solution are mixed at a weight ratio of 1:1-1:3.