JP2009035454A - Spherical mesoporous article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mesoporous article with a novel structure comprising an outer shell having regularly arranged mesopores and an interior cavity, which enables controlled, sustained release of functional substances with a nonconventional, excellent selectivity, is excellent in the adsorption of functional substances and can be suitably used for drug delivery etc. <P>SOLUTION: The problem can be solved by the spherical mesoporous article which has an X-ray refraction pattern having at least one peak at a distance d larger than 2 nm, has the outer shell comprising the mesopores with an average pore diameter of 0.8-20 nm and has the cavity with an outer shell thickness of 0.5-5 μm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spherical mesoporous material having an outer shell composed of regular mesopores and having a cavity inside.

  Conventionally, hollow silica particles having an average particle diameter of about 0.1 to 300 μm are known (see, for example, Patent Document 1 and Patent Document 2). Also known is a method for producing hollow particles composed of a dense silica shell by precipitating active silica from an aqueous alkali metal silicate solution on a core composed of a material other than silica and removing the silica shell without destroying it. (For example, refer to Patent Document 3). Further, micron-sized spherical silica particles having a core-shell structure in which the outer peripheral portion is a shell, the center portion is hollow, the outer shell is denser on the outer side, and has a coarser concentration gradient structure on the inner side are known (for example, Patent Documents). 4). However, it did not have regular mesopores in the outer shell, and was inferior in selectivity and controlled release.

JP-A-6-330606 (pages 1 to 5) JP-A-7-013137 (first page-seventh page) Special Table 2000-500113 (1st page-24th page) JP-A-11-029318 (pages 1 to 13)

  It is an object of the present invention to obtain a spherical mesoporous material capable of controlling selectivity and controlled release of a functional substance, which has never existed before, by providing regular mesopores in the outer shell and cavities inside. There is.

That is, the present invention
(1) having an outer shell composed of mesopores having an X-ray diffraction pattern having at least one peak at a position where the d interval is larger than 2 nm, and having an average pore diameter of 0.8 to 20 nm, and the thickness of the outer shell is A spherical mesoporous material having cavities of 0.5 to 10 μm (2) An object of the present invention is to provide the spherical mesoporous material according to 1 above, wherein the primary particle diameter is 10 to 150 μm.

  The spherical mesoporous material of the present invention can be used in a wide range of fields such as drug delivery carriers, agricultural chemicals, and controlled release of fragrances by supporting a functional substance in the internal cavity.

  The spherical mesoporous material in the present invention refers to a porous material mainly composed of an inorganic oxide having a regular mesoporous structure. Examples of the inorganic oxide include, but are not limited to, silicon oxide, titanium oxide, and zirconia oxide. In view of the ease of synthesis of the regular mesoporous structure and the stability of the structure, it is more preferable to use silicon oxide as the main component.

  The spherical mesoporous material in the present invention preferably has an X-ray diffraction pattern having at least one peak at a position where the d interval is larger than 2 nm, and X having one peak at a position where the d interval is larger than 2 nm. More preferably, it has a line diffraction pattern.

  The spherical mesoporous material of the present invention has an X-ray diffraction pattern having one peak at a position where the d interval is larger than 2 nm, and a peak having a relative intensity larger than 50% of this peak at a position smaller than 2 nm. More preferably.

  The X-ray diffraction pattern can be measured by an X-ray diffraction measurement device (RINT ULTIMA II, manufactured by Rigaku Corporation).

  The spherical mesoporous material in the present invention preferably has a cavity having an outer shell thickness of 0.5 to 10 μm made of a mesoporous material having an average pore diameter of 0.8 to 20 nm.

  When the average pore diameter of the pores in the spherical mesoporous material in the present invention is less than 0.8 nm, the adsorption of the functional substance or the like to the porous silica is not sufficient, and those exceeding 20 nm are substantially produced. It is difficult to. Therefore, from the above viewpoint, the average pore diameter of the spherical mesoporous material in the present invention is 0.8 to 20 nm, preferably 1.5 to 20 nm, and most preferably 4 to 20 nm.

  The method for measuring the average pore diameter of the pores is not particularly limited, and can be calculated, for example, by a known nitrogen adsorption measurement method.

  The fine pores in the range of 0.8 to 20 nm of the spherical mesoporous material in the present invention are preferably 60% or more (volume) of the whole from the viewpoint of supporting a functional substance, more preferably 80%, More preferably, it is 90% or more, and most preferably 95% or more.

  The thickness of the outer shell in the present invention is preferably 0.5 to 10 μm, more preferably 1 to 10 μm, from the viewpoint of supporting a functional substance.

  The method for measuring the thickness of the outer shell is not particularly limited. For example, it can be calculated by observing a pulverized mesoporous material obtained by pulverizing a spherical mesoporous material with a scanning electron microscope.

Cavity volume is 500 [mu] m ³ / number ~1690000μm ³ / Pieces are preferred from the viewpoint of functional substance carried in the present invention, 4000 .mu.m ³ / number ~500000μm ³ / pieces, and even more preferably 4000 .mu.m ³ / number ~62000μm ³ / Pieces .

The method for measuring the cavity volume is not particularly limited, but the radius r of the sphere forming the cavity obtained by observing the pulverized mesoporous material obtained by pulverizing the spherical mesoporous material with a scanning electron microscope From V = 4 / 3πr ³ .

When the specific surface area of the spherical mesoporous material in the present invention is less than 100 m ² / g, the adsorption of the functional substance supported on the spherical mesoporous material may not be sufficient, and the specific surface area is more than 2000 m ² / g. It is practically difficult to manufacture. Therefore, from the above viewpoint, the specific surface area of the mesoporous materials of the present invention is preferably 100-2000 m ² / g, more preferably 300~1500m ² / g, most preferably 450~1500m ² / g.

  The method for measuring the specific surface area is not particularly limited, but can be calculated by a known nitrogen adsorption measurement.

It is not particularly limited pore volume of the spherical mesoporous material in the present invention, ^preferably, 0.1cm ^{3 /g~3.0cm} 3 / ^g, more preferably 0.5 cm ³ / g to 2. 0 cm ³ / g, more preferably it is better that is controlled to be a 1.0cm ³ /g~2.0cm ³ / g. When the pore volume is smaller than the above range, the adsorption amount of the functional substance supported on the spherical mesoporous material may not be sufficient, and when the pore volume is larger than the above range, it is substantially manufactured. Have difficulty.

  The method for measuring the pore volume is not particularly limited, but can be calculated by a known nitrogen adsorption measurement.

The specific surface area (m ² / g), pore volume (cm ³ / g), and average pore diameter (nm) of the spherical mesoporous material of the present invention can be calculated by a known nitrogen adsorption measurement. That is, the average pore diameter can be calculated by a known BJH method, the specific surface area can be calculated by a known BET method, and the pore volume can be calculated by a known BJH method, t method, or the like. The primary particle diameter can be observed with a scanning electron microscope.

  The outer shape of the spherical mesoporous material in the present invention is not limited to a perfect sphere, and is preferably a shape showing a sphere. The outer shape can be observed with a scanning electron microscope.

  If the primary particle size of the spherical mesoporous material in the present invention is less than 10 μm, the adsorption stability of the functional substance support is insufficient, and if it exceeds 150 μm, the functional substance support is extremely inferior. Therefore, from the above viewpoint, the primary particle size of the spherical mesoporous material in the present invention is preferably 10 μm to 150 μm, more preferably 20 μm to 100 μm, and most preferably, from the viewpoint of adsorption stability of the functional substance supported. , 20 μm to 50 μm.

  The shape of the pores of the spherical mesoporous material in the present invention is not particularly limited, but wormhole type, 2d hexagonal type, and 3d hexagonal type are preferable.

  The shape of the pore can be specified by observation with a transmission electron microscope or measurement of an X-ray diffraction pattern.

  The functional substance in the present invention is not particularly limited, but includes nutritional components such as astaxanthin and coenzyme Q-10, pharmacological components such as various pharmaceuticals and physiologically active substances, fragrances, agricultural chemicals, fertilizers, bactericides, and disinfectants. , Chemical substances having various functions and actions, such as antibacterial agents, fungicides, insecticides, insecticides, herbicides, pest repellents, animal repellents, and attractants.

  The method for producing the spherical mesoporous material of the present invention is not particularly limited. For example, by mixing and reacting an inorganic raw material with an organic raw material, an inorganic material skeleton is formed around the organic material as a template. A method of removing the organic substance from the obtained complex after forming a composite of the organic substance and the inorganic substance.

The inorganic raw material is not particularly limited as long as it forms the pore structure of the inorganic oxide after the reaction, but preferably includes silicon-based, titanium-based, zirconia-based materials and the like. Most preferably, it is a silicon-based raw material, and examples thereof include substances containing silicates such as layered silicates and non-layered silicates, and substances containing silicon other than silicates. Examples of layered silicates include kanemite (NaHSi ₂ O ₅ · 3H ₂ O), sodium disilicate crystal (Na ₂ Si ₂ O ₅ ), macatite (NaHSi ₄ O ₉ · 5H ₂ O), and Iraite (NaHSi ₈ O ₁₇ · XH ₂ O), magadiite (Na ₂ HSi ₁₄ O ₂₉ · XH ₂ O), Kenyaite (Na ₂ HSi ₂₀ O ₄₁ · XH ₂ O) and the like. Non-layered silicates include water glass (sodium silicate). ), Glass, amorphous sodium silicate and the like. Examples of the substance containing silicon other than silicate include silica, silica oxide, silica-metal composite oxide, tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylammonium (TMA) silicate, and tetraethyl. Examples thereof include silicon alkoxide such as orthosilicate. These can be used alone or in admixture of two or more.

  Although it does not specifically limit as an organic raw material used as a casting_mold | template, For example, surfactant is mentioned, This can be used individually or in mixture of 2 or more types.

  The surfactant is not particularly limited, but a nonionic surfactant is preferable.

  The nonionic surfactant is not particularly limited. For example, polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene Ether type compounds such as lanolinic acid derivatives, polyoxyethylene polyoxypropylene alkyl ether, polypropylene glycol, polyethylene glycol, and nitrogen-containing compounds such as polyoxyethylene alkylamine can be used. From the viewpoint of the cavity volume, a polyglycerol fatty acid ester obtained by esterifying a fatty acid into polyglycerol is preferable. You may use these individually or in mixture of 2 or more types.

  The polyglycerol fatty acid ester preferably has an HLB of 14.0 to 18.0, more preferably 15.0 to 18.0, and more preferably 15.0 to 16 from the viewpoint of pore regularity and void volume. 0.0 is most preferred. Here, HLB represents the balance between the hydrophilic group and the lipophilic group in the molecule, and is equally divided into 0 when the hydrophilic group in the molecule is 0% and 20 when the hydrophilic group is 100%.

  From the viewpoint of pore regularity and void volume, the polyglycerin fatty acid ester preferably has a content of one kind of polyglycerin selected from glycerin trimer to 10-mer in the polyglycerin composition is 35% or more. . This composition distribution can be analyzed by gas chromatography or liquid chromatography, and in particular, it can be easily analyzed by subjecting polyglycerin to a trimethylsilylated derivative followed by gas chromatography.

  In the polyglycerol fatty acid ester, the number of carbon atoms of the constituent fatty acid of the polyglycerol fatty acid ester is preferably 12 to 14 from the viewpoint of pore regularity and void volume.

  When mixing an inorganic raw material and an organic raw material, an appropriate solvent may be used. Although it does not specifically limit as a solvent, Water, alcohol, etc. are mentioned.

  It is preferable to add a basic substance such as ammonium fluoride to the reaction solution.

  The mixing method of the inorganic raw material and the organic raw material is not particularly limited, but after dissolving the surfactant in the acidic solution, the basic substance and the inorganic raw material are added to the solution, and the temperature is from 20 ° C to 60 ° C. It is preferable to mix for 3 hours to 24 hours. The mixing ratio (weight ratio) between the inorganic raw material and the surfactant is not particularly limited, but inorganic raw material: surfactant = 1: 0.5 to 1: 2 is preferable, and 1: 1 to 1: 1. 5 is more preferable. The mixing ratio (weight ratio) of the inorganic raw material and the basic substance is not particularly limited, but inorganic raw material: basic substance = 100: 0.1 to 100: 10 is preferable, and 100: 1 to 100: 5 is preferable. More preferred.

  The acidic substance for preparing the acidic solution is not particularly limited, and examples thereof include hydrochloric acid, hydrogen bromide, hydrogen iodide, formic acid, acetic acid, nitric acid, sulfuric acid, phosphoric acid and the like.

  The pH condition when the inorganic raw material and the organic raw material are stirred and reacted is not particularly limited as long as it is acidic from the viewpoint of pore regularity and cavity volume, but is preferably pH 3 to pH-3, pH 1 -PH-3 is more preferable, and pH0-pH-3 is more preferable.

  As a method for removing the organic substance from the complex of the organic substance and the inorganic substance, there are a method in which the complex is filtered, washed with water and dried, then baked at 400 ° C. to 600 ° C., and extracted with an organic solvent or the like. Can be mentioned.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example.

Production Example 1
To 180 ml of 1.5N hydrochloric acid, 6.3 g of pentaglycerin monomyristate / (content of glycerin pentamer in the constituent polyglycerin is 42%, HLB15.0, manufactured by Taiyo Kagaku Co., Ltd.) is added and mixed. The myristate was completely dissolved.
To this solution was added 0.06 g ammonium fluoride, 9 g tetraethoxysilane (TEOS) and 15 ml decane. This solution (pH 0 or lower) was stirred in a sealed system at 25 ° C. for 24 hours. The resulting precipitate was collected by filtration, and then washed with ion-exchanged water and filtered three times. After washing with ethanol and filtration, the solid was dried at 60 ° C. for 3 hours and then calcined at 540 ° C. for 6 hours to obtain 2 g of spherical mesoporous material A.

Production Example 2
To 180 ml of 1.5N hydrochloric acid, 6.3 g of pentaglycerin monomyristate / (content of glycerin pentamer in the constituent polyglycerin is 42%, HLB15.0, manufactured by Taiyo Kagaku Co., Ltd.) is added and mixed. The myristate was completely dissolved.
To this solution was added 0.15 g ammonium fluoride, 9 g tetraethoxysilane (TEOS) and 15 ml decane. This solution (pH 0 or lower) was stirred in a sealed system at 25 ° C. for 24 hours. The resulting precipitate was collected by filtration, and then washed with ion-exchanged water and filtered three times. After washing with ethanol and filtration, the solid was dried at 60 ° C. for 3 hours and then calcined at 540 ° C. for 6 hours to obtain 2 g of spherical mesoporous material B.

Production Example 3
To 2.1 g of pentaglycerin monomyristate / (content of glycerin pentamer in constituent polyglycerin is 42%, HLB15.0, manufactured by Taiyo Kagaku Co., Ltd.), 30 g of ion-exchanged water was added and stirred at 40 ° C. for 2 hours. . Thereafter, 40 g of 3N hydrochloric acid was added and stirred at 40 ° C. for 2 hours.
3 g of water glass No. 1 was added to this solution and stirred at 40 ° C. for 65 hours. The resulting precipitate was collected by filtration, and then washed with ion-exchanged water and filtered three times. After washing with ethanol and filtration, the solid was dried at 60 ° C. for 3 hours and then calcined at 540 ° C. for 6 hours to obtain 0.8 g of spherical mesoporous material C.
X-ray diffraction patterns of the obtained spherical mesoporous materials A, B, and C were measured. The result of the spherical mesoporous material A is shown in FIG. 1, the result of the spherical mesoporous material B is shown in FIG. 2, and the result of the spherical mesoporous material C is shown in FIG.

  The X-ray diffraction patterns of the spherical mesoporous materials A, B, and C obtained as shown in FIGS. 1, 2, and 3 had one peak at a position where the d interval was larger than 2 nm.

  The obtained spherical mesoporous materials A, B and C were measured for pore size distribution by a known nitrogen adsorption method (BJH method), and the average pore size was determined. The result of the spherical mesoporous material A is shown in FIG. 4, the result of the spherical mesoporous material B is shown in FIG. 5, and the result of the spherical mesoporous material C is shown in FIG.

  The obtained spherical mesoporous material A has mesopores with an average pore diameter of 10.5 nm, and the spherical mesoporous material B has mesofine particles with an average pore diameter of 13.9 nm as shown in FIGS. The spherical mesoporous material C had pores, and mesopores having an average pore diameter of 6.2 nm.

Specific surface areas (BET method) and pore volumes (BJH method) of spherical mesoporous materials A, B, and C were calculated by a known nitrogen adsorption method. The specific surface area of the spherical mesoporous material A was 642 m ² / g, and the pore volume was 1.8 cm ³ / g. The specific surface area of the spherical mesoporous material B was 490 m ² / g, and the pore volume was 1.4 cm ³ / g. The specific surface area of the spherical mesoporous material C was 1380 m ² / g, and the pore volume was 1.6 cm ³ / g.

  The external shapes of the obtained mesoporous materials A, B, and C were observed with a scanning electron microscope. The results of the spherical mesoporous material A are shown in FIGS. 7 and 8, the results of the spherical mesoporous material B are shown in FIGS. 9 and 10, and the results of the spherical mesoporous material C are shown in FIG.

  As shown in FIGS. 7 and 8, it was confirmed that the obtained spherical mesoporous material A had a spherical shape with a primary particle diameter of 30 μm.

It was confirmed that the spherical mesoporous material B obtained as shown in FIG. 9 and FIG. 10 had a spherical shape with a primary particle diameter of 50 μm.
As shown in FIG. 11, it was confirmed that the obtained spherical mesoporous material C had a spherical shape with a primary particle diameter of 50 μm.

  1 g of each of the spherical mesoporous materials A, B, and C was ground in a mortar to obtain pulverized spherical mesoporous materials A1, B1, and C1. Scanning electron microscope observation results of the pulverized spherical mesoporous materials A1, B1, and C1 are shown in FIGS. 12, 13, and 14, respectively.

As shown in FIGS. 12, 13, and 14, cavities are observed in the pulverized spherical mesoporous materials A1, B1, and C1, and it is confirmed that cavities are formed inside the spherical mesoporous materials A, B, and C. It was done. (A1: Radius 15 μm, outer shell thickness 1.6 μm, radius of the sphere forming the cavity 13.4 μm / B1: radius 25 μm, outer shell thickness 1.4 μm, radius of the sphere forming the cavity 23.6 μm, C1 : Radius 25 μm, outer shell thickness 7 μm, cavity forming sphere radius 18 μm)
When the cavity volume of the spherical mesoporous materials A, B, and C was calculated from the radius of the pulverized spherical mesoporous materials A1, B1, and C1, it was 1007.63.6 μm ³ / piece, 55030.6 μm ³ / piece, and 244429.0 μm ³ / piece. there were.

  The pore shape of the transmission electron microscope of the spherical mesoporous material A was observed with a transmission electron microscope. The observation result of the transmission mesoscopic microscope of the spherical mesoporous material A is shown in FIG.

  It is confirmed from FIG. 15 of the transmission electron microscope observation result and FIG. 1 of the X-ray diffraction pattern measurement result that the pore shape of the spherical mesoporous material A is a wormhole type.

Comparative product production example 1
The water glass solution is emulsified together with a pharmacodynamic liquid paraffin solution of a mixture of sorbitan monostearate and polyoxyethylene sorbitan monooleate to prepare a water-in-oil emulsion, which is then added to the ammonium sulfate solution and allowed to react. Subsequently, the porous body a was obtained by performing filtration, washing, and drying.

  When the X-ray diffraction pattern of the porous body a obtained in Comparative Production Example 1 was measured, no peak was observed.

  When the pore size distribution of the porous body a obtained in Comparative Production Example 1 was measured by a known nitrogen adsorption method, it was widely distributed in the range of 500 nm to 2 μm.

  When the porous body a obtained in Comparative Production Example 1 was observed with a scanning electron microscope, spherical particles of various sizes of 5 to 300 μm were observed.

  When the porous body a obtained in Comparative Example Production Example 1 was ground with a 1 g mortar and the ground porous body was a1, and observed with a scanning electron microscope, large and small amorphous cavities were observed.

  According to the present invention, it is possible to provide a mesoporous material having a novel structure having regular mesopores in the outer shell and cavities inside, and is suitably used for drug delivery by adsorbing a functional substance. And its industrial utility value is great.

FIG. 1 is a diagram showing an X-ray diffraction pattern of a spherical mesoporous material A. FIG. 2 is a diagram showing an X-ray diffraction pattern of the spherical mesoporous material B. FIG. FIG. 3 is a diagram showing an X-ray diffraction pattern of the spherical mesoporous material C. FIG. 4 is a view showing the pore size distribution of the spherical mesoporous material A. FIG. 5 is a view showing the pore size distribution of the spherical mesoporous material B. FIG. FIG. 6 is a view showing the pore size distribution of the spherical mesoporous material C. FIG. FIG. 7 is a view showing a result of observation of the spherical mesoporous material A by a scanning electron microscope. FIG. 8 is a view showing a result of observation of the spherical mesoporous material A by a scanning electron microscope. FIG. 9 is a view showing the result of observation of the spherical mesoporous material B by a scanning electron microscope. FIG. 10 is a diagram showing the result of observation of the spherical mesoporous material B by a scanning electron microscope. FIG. 11 is a diagram showing a result of observation of the spherical mesoporous material C by a scanning electron microscope. FIG. 12 is a view showing a result of observation with a scanning electron microscope of the pulverized spherical mesoporous material A1. FIG. 13 is a view showing a result of observation with a scanning electron microscope of the pulverized spherical mesoporous material B1. FIG. 14 is a view showing a result of observation with a scanning electron microscope of the pulverized spherical mesoporous material C1. FIG. 15 is a diagram showing a transmission electron microscope observation result of the spherical mesoporous material A. FIG.

Claims (3)

It has an outer shell composed of mesopores having an X-ray diffraction pattern having at least one peak at a position where the d interval is larger than 2 nm, an average pore diameter of 0.8 to 20 nm, and the thickness of the outer shell is 0.5. A spherical mesoporous material having a cavity of 10 μm to 10 μm. The spherical mesoporous material according to claim 1, wherein the primary particle diameter is 10 to 150 μm. 3. The spherical mesoporous material according to claim 1 or 2, wherein the porous material is a silica-based material having a skeleton mainly composed of silicon oxide.