JPH1161113A - Inorganic fluorescent porous particle and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing spherical organic fluorescent porous particles wherein the fluorescent elements (fluophor) are uniformly dispersed not only on the surfaces of the particles but also inside thereof. SOLUTION: This method comprises the following steps of (1) to (4): (1) dissolving tetraethoxysilane and tris(acetylacetonato)europium into an alcohol, adding the alcohol solution to a mixture of a water containing ammonium as a basic catalyst and alcohol for hydrolysis reaction, and thus synthesizing a composite oxide sol-containing liquid, (2) synthesizing a composite oxide sol aqueous solution by removing the alcohol component from the composite oxide sol-containing liquid by concentrating the liquid, (3) adding the composite oxide sol aqueous solution to an organic solution so as to form a great number of emulsion particles of sol liquid-drops in the solution, and (4) gelling the emulsion particles by promoting its polymerization reaction, and then dehydrating and burning the resultant gel, thus producing the inorganic fluorescent porous particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to inorganic fluorescent porous particles and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, the following method has been proposed as a method for producing fluorescent particles. That is, a liquid fluorescent material containing a fluorescent element (for example, a solution in which rhodamine B is dissolved in anhydrous alcohol) is put in a container, and a large number of porous particles as a particle base are immersed in the container for a predetermined time, or A method has been proposed in which, after immersing the porous particles, the air inside the container is sucked to make the state close to a vacuum, and the fluorescent material is sealed inside the pores of the porous particles.

[0003] However, in this method, although the doping amount of the fluorescent element with respect to the porous particles can be increased, the concentration quenching phenomenon of the fluorescence emission due to the aggregation of many fluorescent elements. As a result, there is a problem that the fluorescence intensity corresponding to the doping amount cannot be obtained. As described above, in the conventional impregnation method, it is difficult to uniformly disperse the fluorescent element throughout the inside of the particle,
There was a problem in the obtained fluorescence intensity.

[0004] In addition, a method of firing a phosphor oxide and a base oxide (such as silica) at a high temperature and then pulverizing the same has been performed. However, even in this method, the fluorescent element is uniformly dispersed over the entire base. It was difficult to disperse, and the shape of the particles was not constant (not the same shape as each other) and was crushed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has an object to form a spherical shape in which a fluorescent element (phosphor) is uniformly scattered not only on the surface but also inside the particle. It is an object of the present invention to provide inorganic fluorescent porous particles and a method for producing the same.

[0006]

The inorganic fluorescent porous particles according to claim 1 have a porosity of 50 to 90% and a particle diameter of 0.1.
The phosphor has a spherical shape of about 500 μm, and the phosphors are uniformly dispersed throughout the particles, so that the emission of the phosphors inside the particles can be observed from the outside.

[0007] The inorganic fluorescent porous particles according to claim 2 are the inorganic fluorescent porous particles according to claim 1,
The particle body is made of SiO ₂ , and the phosphor is a rare earth element such as europium.

[0008] The method for producing inorganic fluorescent porous particles according to claim 3 is a method comprising the following steps (A) to (C).

(A) A mixed solution obtained by dissolving a metal alkoxide containing aluminum, silicon or the like as a metal component and a fluorescent material is hydrolyzed to synthesize a composite oxide sol aqueous solution.

(B) The aqueous solution of the composite oxide sol is added to an organic solvent to form a large number of emulsion particles as sol droplets in the organic solvent.

(C) The emulsion particles are gelled by accelerating a polymerization reaction, and then the gel is dried and fired to produce inorganic fluorescent porous particles.

The method for producing inorganic fluorescent porous particles according to claim 4 is a method comprising the following steps (1) to (4).

(1) A metal alkoxide containing aluminum, silicon, or the like as a metal component and a fluorescent material are dissolved in alcohol, and the alcohol solution is added to a mixed solution of water and alcohol containing a basic catalyst to carry out a hydrolysis reaction. Is caused to synthesize a composite oxide sol-containing liquid. (2) The alcohol is removed by concentrating the liquid containing the complex oxide sol to synthesize a complex oxide sol aqueous solution.

(3) The aqueous solution of the composite oxide sol is added to an organic solvent to form a large number of emulsion particles as sol droplets in the organic solvent.

(4) The emulsion particles are gelled by accelerating the polymerization reaction, and then the gel is dried and fired to produce inorganic fluorescent porous particles.

According to a fifth aspect of the present invention, there is provided a method for producing an inorganic fluorescent porous particle according to the third or fourth aspect, wherein the aqueous composite oxide sol solution is passed through a porous membrane. The method is characterized in that a large number of emulsion particles as sol droplets are formed in the organic solvent by extruding the particles into an organic solvent.

According to a sixth aspect of the present invention, in the method for producing an inorganic fluorescent porous particle according to the fifth aspect, the porous membrane extends in a thickness direction and penetrates; This is a method characterized by having a large number of through-holes whose hole diameters are substantially uniform with each other.

The method for producing inorganic fluorescent porous particles according to claim 7 is the method for producing inorganic fluorescent porous particles according to any one of claims 3 to 6, wherein the metal in step (A) is used. The method is characterized in that the content of the alkoxide is 1 mol / liter or less.

The method for producing inorganic fluorescent porous particles according to claim 8 is the method for producing inorganic fluorescent porous particles according to any one of claims 3 to 6, wherein the metal in step (A) is used. Alkoxide content of 0.05 to
The method is characterized by being 0.3 mol / liter.

According to a ninth aspect of the present invention, there is provided a method for producing an inorganic fluorescent porous particle according to any one of the third to eighth aspects, wherein the metal alkoxide is tetraethoxysilane. And the like.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION As metal elements in a metal alkoxide usable in the present invention, silicon (Si), aluminum (Al), titanium (Ti), zirconium (Z
r), magnesium (Mg), calcium (Ca), and the like. The alkoxy group is not particularly limited.
Examples include a methoxy group, an ethoxy group, a propoxy group and a butoxy group. Accordingly, metal alkoxides include tetramethoxysilane (methyl orthosilicate), tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, titanium tetramethoxide (methyl orthotitanate), titanium tetraethoxide, titanium tetrabutoxide, and aluminum methoxy. And aluminum ethoxide.

The content ratio of the metal alkoxide is not particularly limited, but is preferably 1 mol / liter or less. If the compounding ratio of the metal alkoxide exceeds 1 mol / liter, there is a possibility that a problem such as precipitation without forming a sol may occur. The preferred range is 0.05
To 0.3 mol / l, and a more preferred range is 0.1 to 0.2 mol / l.

As the fluorescent raw material, any material may be used as long as it emits fluorescence having a wavelength different from the above-mentioned wavelength by the wavelength of the excitation light and the excitation light. For example, neodymium (N
d), compounds containing a lanthanoid element such as europium (Eu), terbium (Tb), rhodamine, coumarin, fluorescein, umbellifene, eosin, esculin, etc. (Organic fluorescent materials such as rhodamine are coordinated with a metal. It is necessary to incorporate the metal complex into the matrix). In addition, the main components are highly pure metals such as zinc, cadmium, calcium, aluminum and yttrium, such as oxides, sulfides, silicates and tungstates.
Activators such as silver, copper, lead, and europium and fluxes are added, and the mixture is baked at a high temperature (for example, ZnS (M
n), ZnS (Cu), CaS (Bi), ZnO (Z
n) etc. may also be used. In the case of a compound containing a lanthanoid element, a non-ionic compound such as a β-diketone compound such as trisacetylacetonatoeuropium, dipyrovaylmethanatoeuropium, and hexafluoroacetylacetonatoeuropium is preferred. Is preferred in that precipitation of the sol can be prevented.

The mixing ratio of the fluorescent material is preferably 1 mol% or less based on the metal alkoxide.
0.1 to 0.7 mol%, preferably 0.2 to 0.7 mol%.
More preferably, it is 0.6 mol%. When the mixing ratio exceeds 1 mol%, there is a possibility that a problem such as precipitation of the sol may occur.

The above-described metal alkoxide and the fluorescent material are dissolved in an organic solvent compatible with water such as alcohol, and the solution is dissolved in water containing a basic catalyst and water such as alcohol. Although it is added to a mixture of organic solvents, any of the above-mentioned organic solvents may be any as long as it can dissolve the metal alkoxide and the fluorescent raw material to be used and are compatible with water, For example, alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol and butanol, ethylene glycol, ethylene oxide, triethanolamine and the like can be mentioned. Examples of the basic catalyst used in the present invention include ammonium, ethylenediamine, pyridine and the like. The addition amount of the basic catalyst is 0.0
It is preferably from 1 to 0.1 mol / liter,
More preferably, the amount is from 0.05 to 0.08 mol / l. If the added amount of the basic catalyst exceeds 0.1 mol / l, there is a possibility that sol precipitation may be induced, and conversely, 0.1 mol / l may be caused.
When the amount is less than 01 mol / liter, there is a possibility that a problem that the hydrolysis and the polymerization reaction do not sufficiently proceed and a sol is not formed may occur.

As described above, the metal alkoxide and the fluorescent material are dissolved in an organic solvent such as alcohol, and the solution is mixed with water containing a basic catalyst and an organic solvent (an organic solvent compatible with water). It is added to a solvent to form a sol in the mixed solvent. Thereafter, the organic solvent is removed by concentration to prepare an aqueous sol solution (aqueous composite oxide sol solution).

Thereafter, the aqueous solution of the composite oxide sol is added to an organic solvent. The organic solvent is not particularly limited, and any organic solvent having a solubility in water of 5% or less can be used. It does not matter. Specific examples are listed below.

Aliphatic hydrocarbons; n-hexane, isohexane, n-heptane, isoheptane, n-octene,
Isooctene, gasoline, petroleum ether, kerosene, benzine, mineral spirit, etc.

Alicyclic hydrocarbons; cyclopentane, cyclohexane, cyclohexene, cyclononane and the like;

Aromatic hydrocarbons; benzene, toluene,
Xylene, ethylbenzene, propylbenzene, cumene, mesitylene, tetralin, styrene, etc.

Ethers such as propyl ether and isopropyl ether;

Halogenated hydrocarbons: methylene chloride, chloroform, ethylene chloride, trichloroethane, trichloroethylene and the like.

Esters: ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl acetate, isoamyl acetate, butyl lactate, methyl propionate, ethyl propionate, butyl propionate , Methyl butyrate, ethyl butyrate, butyl butyrate and the like.

The above organic solvents may be used alone,
Two or more kinds may be used in combination.

When a surfactant is blended with the organic solvent, the surfactant is not particularly limited except that it is a nonionic one. Preferred specific examples are listed below.

Polyoxyethylene sorbitan aliphatic ester type polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate;
Polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan triolate, polyoxyethylene sorbitan stearate and the like.

Polyoxyethylene higher alcohol ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octyl phenol ether, polyoxyethylene nonyl phenol ether and the like.

Polyoxyethylene aliphatic ester type polyoxyethylene glycol monolaurate, polyoxyethylene glycol monostearate, polyoxyethylene glycol stearate, polyoxyethylene glycol monooleate and the like.

Glycerin aliphatic ester type; stearic acid monoglyceride, oleic acid monoglyceride and the like.

Polyoxyethylene sorbitol aliphatic esters; such as polyoxyethylene sorbite tetraoleate.

The above surfactants may be used alone or in combination of two or more. The amount of the surfactant used is preferably about 10% by weight or less of the organic solvent used, and more preferably about 0.1 to 3% by weight.

By extruding the aqueous solution of the composite oxide sol into an organic solvent through a porous film to form a large number of emulsion particles, which are sol droplets, in the organic solvent, the diameter of the emulsion particles to be formed is limited to a certain degree. It is preferable because they are aligned. In this case, it is preferable that the surface of the porous film is subjected to a hydrophobic treatment. A method for producing a porous membrane is already known, for example, as described in JP-A-61-408.
It can also be produced using a method described in JP-A-41-41 or JP-A-50-140566.

As long as the porous membrane used has hydrophobicity, it is not necessary to perform the hydrophobic treatment. For example, when a film made of a fluorine-based resin such as polyimide, polyethylene terephthalate, or Teflon (registered trademark of DuPont) is used, a hydrophobic treatment is unnecessary because the film itself has hydrophobicity. Further, since it is not affected by alkali, it is not necessary to consider chemical deterioration. However, when the surface does not have hydrophobicity, it is necessary to subject the surface to a hydrophobic treatment.

There are no particular limitations on the means for the hydrophobizing treatment, and thermosetting silicone oils such as dimethylpolysiloxane and methylhydrogenpolysiloxane, silicone resins such as silicone emulsions and silicone resins, methyltrimethoxysilane, hexamethyldisilane Silane coupling agents such as vinyltrimethoxysilane and trimethylchlorosilane, cyclic silicone compounds such as dihydrogenhexamethylcyclotetrasiloxane and trihydrogenpentamethylcyclotetrasiloxane, isopropyltristearoyl titanate and isopropyltri (N-aminoethyl) -) Titanate-based coupling agents such as titanate, aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate, fluorine silicon Down coating agents include a method of treatment with a fluorine-based coating agent, in this also includes the method by plasma polymerization of siloxanes.

Further, it is preferable that the pores in the porous membrane extend in the thickness direction and penetrate therethrough so that the pore diameters are substantially uniform with each other, so that particles having a more uniform diameter can be obtained with high productivity. It is preferable in that it can be used. That is, by using such a porous membrane, it is possible to shorten the time until the aqueous solution of the composite oxide sol enters the porous membrane and comes out of the porous membrane, thereby preventing the pressure loss of the aqueous solution from occurring. In particular, when producing particles having a small particle diameter or when using an aqueous solution of a raw material having a large viscosity, the production amount per unit time can be increased. In addition, since the diameters of a large number of through holes are substantially uniform, the diameters of the obtained particles are uniform.

The method for obtaining such a porous film having through holes extending in the thickness direction is not particularly limited. For example, a porous film having a large number of through holes formed by irradiating a particle beam may be used. it can. As particle beams, in addition to neutron beams,
Electron beams, alpha rays, etc. may be used. By using a porous membrane provided with through holes by irradiating a particle beam such as a neutron beam,
The pore size distribution of the opened pores becomes narrow (99% or more falls within ± 10%), and the particle size distribution of the obtained microspheres becomes significantly sharp.

Further, a porous film provided with through holes by irradiating a laser can be used. In this case, although more expensive than the case of using a neutron beam, the pore size distribution is further narrowed (99% or more falls within ± 1%), and the particle size distribution of the obtained microspheres is naturally narrower. Become. In particular, when a laser having a short wavelength of 355 nm or less is used, the above-mentioned effect is remarkable because the shape of the peripheral portion of the opening on the surface of the porous film is not disturbed. Since holes are formed by cutting chemical bonds instead of holes, the shape of the periphery of the holes on the surface of the porous membrane is not disturbed.) When a laser is used, the film thickness is desirably 10 times or less the pore diameter. In addition, it is preferable to use an excimer laser as a laser and form a hole on the porous film by forming an image of a pattern on a mask on the porous film by a stepper (reducing exposure apparatus for semiconductor), but it is not necessary to use this method. Absent. Inorganic uniform microspheres manufactured by using a porous membrane provided with through holes by irradiating a laser having a wavelength of 355 nm or less have a very narrow volume standard deviation of particle size distribution of 10% or less of the average particle size. is there.

A porous polymer film made of polycarbonate or polyester having a through-hole formed by irradiating with a neutron beam and then etching with an aqueous alkali solution is used as a general porous membrane.
Commercially available from Electric (GE)
Nomura Microscience Co., Ltd., trade name: Neuropore filter), which can be used as the porous membrane in the present invention. Among them, it is desirable to use a polyester film having excellent chemical resistance.

As a method for converting a large number of emulsion particles, which are sol droplets formed in an organic solvent, into microspheres, a polymerization reaction is promoted to gel the emulsion particles of the sol, and this is heated to 40 to 80 ° C. Aged for several hours to tens of hours, filtered, washed with water, dried,
A method of firing at about 0 to 1,000 ° C. is preferred.

The method of promoting the polymerization reaction includes a method of heating, a method of adding a polymerization accelerator, and a method of irradiating light. As the polymerization accelerator, at least one selected from the group consisting of halides of alkaline earth metals, inorganic acids, organic acids, ammonium salts of inorganic acids, ammonium salts of organic acids, and carbonates of alkali metals.
Species and the like are not limited thereto, but inorganic electrolytes such as ammonium bicarbonate, ammonium chloride, ammonium nitrate, ammonium sulfate, potassium chloride and potassium hydrogen carbonate are preferred.

The inorganic fluorescent porous particles produced according to the present invention can be used as tracer particles in measuring the flow of a fluid. More specifically, for example, measuring the velocity of a fluid in an engine or other combustor, a burner, a silencer (silencer), a heat exchanger, etc., visualizing the distribution (behavior) of the fluid, or mixing a plurality of types of fluids It can be used as a tracer particle for visualization of the state. The fluid supplied with the tracer particles is irradiated with excitation light such as ultraviolet light to fluoresce the tracer particles, and the flow of the fluid is observed by observing the fluid through a filter through which the fluorescence passes and the excitation light does not pass. measure. If the tracer particles are observed through a filter that does not allow the excitation light to pass and only allows the fluorescence emitted by the excitation light to pass, for example, the incident window, dust, light that has returned upon hitting an obstacle such as a tube wall, is blocked by the filter. Therefore, the only light observed is fluorescence emitted from the tracer particles. Thereby, the error of the fluorescence intensity can be reduced, the movement of the tracer particles can be clearly observed, the measurement error of the fluid is extremely reduced (the S / N ratio is increased), and the reliability is improved. Further, tracer particles having an extremely small particle size can be used. The use of particles having a smaller particle diameter is advantageous because the followability of the fluid is improved and the measurement error is reduced. That is, according to the present invention, as described above, since only light from particles can be observed, it is not necessary to use so large particles, and even if small particles with a particle diameter of about 1 μm are used, sufficient light can be captured. High, high S /
Measurement at the N ratio becomes possible. Further, in the fluorescent porous particles of the present invention, since the phosphors are uniformly scattered throughout the particles, the light emission of each particle becomes the same, the measurement error can be further reduced, and the measured value can be reduced. Reliability is increased. The preferred range of the average particle size of the tracer particles that can be used in the present invention is not particularly limited, but may be 0.1 to 0.1.
To 500 μm, more preferably 1.0 to 3 μm.
00 μm. The porosity is 50 to 90%.
If the porosity is less than 50%, the ability to follow the fluid may be poor, and if it exceeds 90%, the mechanical strength of the particles may be poor. If the shape of the tracer particles is spherical, not only can secondary aggregation be prevented, but also the particle 1
The way of shining one by one becomes further the same, and the measurement accuracy becomes higher.

The fluorescent porous particles obtained according to the present invention can be used for measuring the temperature of a fluid. The temperature of the fluid is measured by observing the fluorescence intensity of the tracer particles. That is, the intensity of the fluorescence emitted from the phosphor generally decreases (decreases) as the temperature increases. Utilizing this phenomenon, it is possible to irradiate excitation light to a fluid to which tracer particles (fluorescent tracer particles) containing a fluorescent substance are quantitatively supplied, and to measure the temperature of the fluid based on the intensity of fluorescence at that time. it can.

That is, first, fluorescent tracer particles are quantitatively supplied to a fluid by a conventionally known powder supply device. Next, the fluid is irradiated with excitation light such as ultraviolet light. The emitted fluorescence is observed by, for example, a fluorimeter or a multi-channel photodetector, and the spectrum of the fluorescence is recognized, for example, and the temperature of the fluid is determined from the intensity of the fluorescence. At this time, it is preferable to see the maximum fluorescence intensity.

If the relationship between the fluorescence intensity of the fluorescent tracer particles used and the temperature is not known, it is necessary to prepare a calibration curve representing the relationship between the two in advance. Alternatively, the relationship between the two (fluorescence intensity and temperature of specific fluorescent particles) is stored in a computer in advance, and the temperature of the fluid is output simply by inputting the fluorescence intensity or observing the fluorescence. It can be programmed as follows.

It is also possible to measure the fluorescence intensity ratio and determine the temperature of the fluid from the measured value. That is, the fluorescence intensity ratio in the fluorescence spectrum of the phosphor is the same as the fluorescence intensity.
Generally, it decreases (decreases) as the temperature increases.
Therefore, the ratio between the fluorescence intensity of one peak and the fluorescence intensity of another peak in the emitted fluorescence spectrum is measured (preferably one peak is the peak showing the maximum fluorescence intensity), and the measurement is performed. The temperature of the fluid can also be determined from the value.

The maximum fluorescence intensity ratio can be measured using two types of fluorescent tracer particles, and the temperature of the fluid can be measured from the measured value.

That is, two kinds of fluorescent tracer particles are quantitatively supplied to one fluid. The two types of particles here are fluorescent tracer particles in which the peaks showing the maximum fluorescence intensity appear at different positions (preferably at positions separated by 20 nm or more, more preferably at positions 30 nm or more, more preferably at positions separated by 50 nm or more). Need to be. Then, the fluid is irradiated with excitation light to fluoresce the tracer particles, and the fluorescence spectrum is measured. Measure the ratio of the peak that shows the maximum fluorescence intensity of one fluorescent tracer particle that appears in the spectrum to the peak that shows the maximum fluorescence intensity of the other fluorescent tracer particle, and measure the temperature of the fluid from this measured value. Can also.

Using a plurality of the tracer particles,
The mixed state of a plurality of fluids can be visualized. That is, for all of the fluids flowing to be mixed,
Supplying fluorescent tracer particles having a temperature-dependent fluorescence intensity so that the fluorescence wavelength differs for each fluid, and irradiating the mixed fluid obtained by mixing the plurality of fluids with excitation light such as ultraviolet light to emit the tracer particles. By measuring the flow of the mixed fluid by observing the fluid through a filter that does not allow the excitation light to pass and allows the fluorescence to pass, and observes the intensity of the fluorescence to determine the mixing. The temperature of the fluid can also be determined. For example, a tracer particle A (fluorescent color; green) is supplied to the fluid A, a tracer particle B (fluorescent color; blue) is supplied to the fluid B, and a tracer particle C (fluorescent color; red) is supplied to the fluid C. All the fluids are mixed, and each particle is fluoresced by irradiating with excitation light having a wavelength of X nm. When the mixed fluid is filtered through a filter that blocks light having a wavelength of X nm and allows fluorescence emitted from each particle to pass through, for example, with a color camera (such as a CCD camera), the movement of each particle can be clearly identified. Observation can be made, and the way of movement of each of the fluid A, the fluid B, and the fluid C in the mixed fluid, the degree of mixing, and the like can be clearly recognized. In the above case, in the case of photographing with a black and white camera (CCD camera or the like), three cameras are prepared, one for particle A photographing, the other for particle B photographing,
The other one is used for imaging particles C, and each images the fluid through a filter that allows only the fluorescence of the assigned particle to pass. Then, by processing three images taken by each camera, the movement of each particle can be observed, and the mixed state of the three fluids can also be grasped. At the same time, the fluorescence intensity and spectrum can be observed to determine the temperature (temperature distribution) of the mixed fluid. In addition, if the particle body is silica (SiO) ₂ , it will not break even in a high-temperature fluid because of its excellent heat resistance.

When measuring the temperature of the fluid, a filter that does not allow the excitation light to pass and the fluorescence does not need to be used as long as the fluorescence spectrum can be recognized.

The excitation light that can be used in the present invention is not particularly limited, and may be an excimer laser, a nitrogen laser, an ultraviolet ray,
Short wavelength of visible light, light from the _{D 2} lamp, light rays from the Hg lamp, also visible laser (YAG / SHG) 5
32 nm, an Ar ion laser or other lasers. In the case where a continuous wave laser or a lamp light source is used, there is an advantage that fluorescence can be connected in a linear manner and an image can be taken. As the filter that can be used in the present invention, any filter can be used as long as it can pass only a wavelength having a certain specific width. For example,
Assuming that the wavelength of the excitation light is 500 nm and the fluorescence emitted upon receiving the excitation light is around 600 nm,
A filter that can pass only light of about 0 ± 20 nm will be used.

A device for supplying tracer particles to a fluid is not particularly limited, and a measuring wheel type powder feeder (having a rotating shaft extending vertically and having a long groove for accommodating tracer particles extending circumferentially on the upper surface). A conventionally known feeding device such as a rotary powder feeding device having a rotating disk and sending the tracer particles to the outside of the device main body by the air pressure difference between the inside and the outside) or a screw type powder feeder can be used, but the feeding accuracy is high. It is preferable to use a measuring wheel type powder feeder.

[0062]

Example 1 Example 1 0.15 mol of tetraethoxysilane, trisacetylacetonatoeuropium [Eu (C ₅ H ₇ O ₂ ) ₃ ]
7.5 × 10 ⁻⁴ mol was dissolved in 500 ml of ethanol. This solution was treated with ammonia 0.1 as a basic catalyst.
500 ml of water to which 072 mol was added and 5 parts of ethanol
It was dropped at a rate of 0.02 ml / s into 00 ml of the mixed solution. After completion of the dropwise addition, the solution was concentrated under reduced pressure at 35 ° C. to remove ethanol, and a composite oxide sol aqueous solution having a solid content of 10% was obtained.

On the other hand, as shown in FIG. 1, a cylindrical porous glass tube (31) (having a pore diameter of 0.5 μm) previously hydrophobicized was used.
m) was prepared. Reference numeral (32) in the figure is a module equipped with the cylindrical porous glass tube (31), reference numeral (33) is a pump, reference numeral (34) is a pressure gauge, reference numeral (35) is an oil phase line,
Reference numeral (36) denotes an aqueous phase line, reference numeral (37) denotes an oil phase tank, reference numeral (38) denotes an aqueous phase tank, reference numeral (39) denotes a pressurizing tank, and reference numeral (40) denotes a pressure gauge.

The resulting composite oxide sol aqueous solution was film-emulsified in toluene in which 10% of sorbitan monolaurate was dissolved through the above-mentioned emulsion particle production apparatus (A) through a cylindrical porous glass tube (31). did.

The emulsion solution thus obtained is
A 1.5 M aqueous solution of ammonium bicarbonate was added as a gelling polymerization reaction accelerator at a ratio of 4.3 ml / g SiO ₂ , followed by stirring to carry out an interfacial reaction. After stirring for 30 minutes, the gel was aged by standing for 1 day, and a powder was obtained by filtration and dried.
By baking at 00 ° C., fluorescent silica porous spherical particles having an average particle diameter of 2 μm and a porosity of 80% were obtained.

The obtained fluorescent porous silica particles were irradiated with ultraviolet light of 266 nm as excitation light,
Observation of the particles with a microscope through a filter that can pass only light of 0 nm confirmed that the phosphor (europium) was uniformly dispersed throughout the particles.

Comparative Example 1 0.15 mol of tetraethoxysilane was added to 50 parts of ethanol.
Dissolved in 0 ml. 0.02 ml / s of this solution was added to a mixed solution of 500 ml of water and 500 ml of ethanol to which 0.072 mol of ammonia was added as a basic catalyst.
At a speed of. After completion of the dropwise addition, further trisacetylacetonato europium _{[Eu (C 5 H 7 O} 2) 3]
7.5 × 10 ⁻⁴ mol was added to obtain a mixed solution.

The obtained solution was mixed with sorbitan acid monolaurate through a cylindrical porous glass tube (31) using the upper emulsion particle producing apparatus as in Example 1 above.
% Dissolved in toluene.

The emulsion solution thus obtained is
A 1.5 M aqueous solution of ammonium bicarbonate was added as a gelling polymerization reaction accelerator at a ratio of 4.3 ml / g SiO ₂ , followed by stirring to carry out an interfacial reaction. After stirring for 30 minutes, the gel was aged by standing for 1 day, and a powder was obtained by filtration and dried.
By baking at 00 ° C., fluorescent silica porous spherical particles having an average particle diameter of 2 μm and a porosity of 80% were obtained.

The obtained fluorescent silica porous spherical particles were irradiated with ultraviolet light of 266 nm as excitation light,
Observing the particles with a microscope through a filter that allows only 0 nm light to pass, a fluorescent substance (europium)
It can be confirmed that the position where is present is uneven inside the particles and is unevenly scattered.

Example 2 Instead of trisacetylacetonatoeuropium, trisacetylacetonatoterbium [Tb (C ₅ H
₇ O ₂ ) ₃ ] was used in the same manner as in Example 1 to obtain fluorescent silica porous spherical particles having an average particle diameter of 2 μm and a porosity of 80%. The obtained fluorescent silica porous spherical particles are irradiated with ultraviolet light of 248 nm as excitation light,
Observation of the particles with a microscope through a filter capable of transmitting only light of 0 to 570 nm confirmed that the phosphor (terbium) was uniformly dispersed throughout the particles.

Example 3 Cylindrical porous glass tube having a pore diameter of 3.0 μm (31)
Fluorescent silica porous spherical particles having an average particle diameter of 5 μm and a porosity of 80% were obtained in the same manner as in Example 1 except that the above was used.

The obtained fluorescent silica porous spherical particles were irradiated with ultraviolet light of 266 nm as excitation light,
Observation of the particles with a microscope through a filter that can pass only light of 0 nm confirmed that the phosphor (europium) was uniformly dispersed throughout the particles.

Example 4 A thin film (trade name; Neuro; trade name) having a large number of through holes penetrating in the thickness direction and having a substantially uniform hole diameter was obtained by irradiating a neutron beam and etching the resulting defects with an alkaline aqueous solution. A pore filter, manufactured by General Electric Co., Ltd.) was dried at 110 ° C. for 24 hours, and then immersed in a 10% by weight toluene solution of triethylchlorosilane at room temperature and subjected to a silane coupling treatment to make the surface of the thin film hydrophobic. did. The pore diameter of the hydrophobized thin film was 0.20 μm, and the film thickness was 15 μm.

The above thin film was mounted as a porous film in an emulsifying apparatus as shown in FIG. 2, and the aqueous solution of the composite oxide sol obtained in Example 1 was mixed with 20 g / liter of polyoxyethylene (20) sorbitan triolate. Hexane solution 800m
1 was press-fitted using a syringe pump. The conditions at the time of press-fitting were 1 g / cm ^{2 of} press-in amount per minute and a temperature of 25 ° C.
Thereby, a large number of emulsion particles were formed in the solution.

Here, the apparatus shown in FIG. 2 will be briefly described. Reference numeral (10) is a fixed-quantity syringe pump unit. A porous membrane (12) is attached to the tip of this metering syringe pump (10).
Is installed. Symbol (14) is the porous membrane (12)
It is a support net for supporting. Reference numeral (16) denotes a tubular reaction vessel, which is connected to the quantitative syringe pump section (10). Reference numeral (20) denotes a feed tube, which can supply an organic solvent (25) in an organic solvent beaker (24) into the reaction vessel (16) by a metering pump (22). However, complex oxide sol aqueous solution (11)
Can be quantitatively injected into the organic solvent (25) in the reaction vessel (16) by the quantitative syringe pump section (10). A reaction vessel (1
The organic solvent in 6) is returned to the organic solvent beaker (24) again by the delivery pipe (26).

When a solution in which a large number of emulsion particles were formed was added to 1 liter of a previously dissolved 1.5 mol / liter ammonium bicarbonate solution, a water-insoluble precipitate gradually formed. Then leave it for 2 hours,
After filtration and separation, washing with water and methanol, 24 hours at 110 ° C.
Dried for hours. Thus, fluorescent silica porous particles were obtained. The average particle diameter of the obtained silica microspheres was 1.2.
μm, porosity 80%, volume standard deviation 0.2 μm
As in Example 1, observation with a microscope confirmed that the phosphors were uniformly dispersed throughout the particles.

Example 5 Fluorescent alumina porous spherical particles having an average particle diameter of 2 μm and a porosity of 80% were obtained in the same manner as in Example 1 except that isopropoxyaluminum was used instead of tetraethoxysilane.

The obtained fluorescent alumina porous spherical particles were irradiated with ultraviolet light of 266 nm as excitation light,
Observation of the particles with a microscope through a filter capable of transmitting only light of 30 nm confirmed that the phosphor (europium) was uniformly dispersed throughout the particles.

[0080]

According to the production method of the present invention, spherical inorganic fluorescent porous particles are obtained in which the fluorescent element (phosphor) is present not only on the surface but also in the particles and is uniformly dispersed throughout the particles. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an apparatus used in Example 1.

FIG. 2 is a schematic explanatory view of an apparatus used in Example 4.

[Explanation of symbols]

 10 Quantitative syringe pump section 12 Porous membrane 14 Support net 16 Reaction vessel 20 Inlet tube 22 Quantitative pump 24 Organic solvent beaker 25 … Organic solvent 26… Delivery pipe 31… Cylindrical porous glass tube 32… Module 33… Pump 34… Pressure gauge 35… Oil phase line 36… Water phase line 37 …… Oil phase tank 38 …… Aqueous phase tank 39 …… Pressurization tank 40 …… Pressure gauge

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Onishi 4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Hikaru Hirano 4-chome, Hirano-cho, Chuo-ku, Osaka, Osaka No. 1-2 in Osaka Gas Co., Ltd.

Claims (9)

[Claims] 1. A porosity of 50 to 90% and a particle size of 0.1 to 50.
Inorganic fluorescent porous particles having a spherical shape of 0 μm, in which phosphors are uniformly scattered throughout the particles, and the emission of the phosphors inside the particles can be observed from the outside. 2. The inorganic fluorescent porous particles according to claim 1, wherein the main body of the particles is made of SiO ₂ and the phosphor is a rare earth element such as europium. 3. A method for producing inorganic fluorescent porous particles, comprising the following steps (A) to (C). (A) A mixed solution obtained by dissolving a metal alkoxide containing aluminum, silicon or the like as a metal component and a fluorescent material is hydrolyzed to synthesize an aqueous composite oxide sol solution. (B) The aqueous solution of the composite oxide sol is added to an organic solvent to form a large number of emulsion particles as sol droplets in the organic solvent. (C) The emulsion particles are gelated by accelerating a polymerization reaction, and then the gel is dried and fired to produce inorganic fluorescent porous particles. 4. A method for producing inorganic fluorescent porous particles, comprising the following steps (1) to (4). (1) A metal alkoxide containing aluminum or silicon as a metal component and a fluorescent material are dissolved in an organic solvent compatible with water such as alcohol, and the solution is mixed with water containing a basic catalyst and water such as alcohol. It is added to a mixed solution of compatible organic solvents to cause a hydrolysis reaction, thereby synthesizing a mixed oxide sol-containing liquid. (2) The organic solvent is removed by concentrating the liquid containing the composite oxide sol to synthesize an aqueous solution of the composite oxide sol. (3) The aqueous solution of the composite oxide sol is added to an organic solvent to form a large number of emulsion particles as sol droplets in the organic solvent. (4) The emulsion particles are gelled by accelerating a polymerization reaction, and then the gel is dried and fired to produce inorganic fluorescent porous particles. 5. The method for producing inorganic fluorescent porous particles according to claim 3, wherein the aqueous solution of the composite oxide sol is extruded into an organic solvent through a porous film to form emulsion particles as sol droplets. Is produced in the organic solvent. 6. The method for producing inorganic fluorescent porous particles according to claim 5, wherein the porous film has a large number of through holes extending in the thickness direction and penetrating therethrough, and having substantially uniform pore diameters. A method for producing inorganic fluorescent porous particles. 7. The method for producing inorganic fluorescent porous particles according to any one of claims 3 to 6, wherein the content ratio of the metal alkoxide in the step (A) is 1 mol / liter or less. A method for producing inorganic fluorescent porous particles. 8. The method for producing inorganic fluorescent porous particles according to claim 3, wherein the content of the metal alkoxide in the step (A) is 0.05 to 10%.
A method for producing inorganic fluorescent porous particles, characterized in that the amount is 0.3 mol / liter. 9. The method for producing inorganic fluorescent porous particles according to claim 3, wherein the metal alkoxide is a silicon alkoxide such as tetraethoxysilane. A method for producing porous particles.