JPH0775728A - Production of uniform inorganic microbead - Google Patents

Abstract

PURPOSE:To freely produce almost uniform inorg. microbeads having a smaller diameter or a larger diameter by making an aq. inorg. compd. soln. jet into org. solvent through a nozzle while impressing a fixed voltage between the soln. and an electrode furnished separately from the nozzle. CONSTITUTION:(i) A soln. contg. an inorg. compd. selected from the silicates of alkali metals, the halides of alkaline-earth metals and the sulfates of copper- family elements and iron-family elements is admixed with (ii) org. solvent to prepare a W/O type emulsion. (iii) An aq. soln. of the compd. such as the halides of alkaline-earth metals, inorg. acids, org. acids or the ammonium salts of inorg. acids and capable of forming a water-insoluble precipitate by the reaction in aq. soln. with the compd. of (i) is added before or after the emulsion is formed to produce an inorg. microbeads. Meanwhile, an aq. soln 1 of (i) is jetted into an org. solvent 3 through a nozzle 2 while impressing a fixed voltage between the soln. and an electrode 4 when the emulsion of (ii) is prepared.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an inorganic microsphere having a uniform particle size, and more particularly to a method for producing a fine inorganic sphere using a solution reaction.

The microspheres obtained according to the present invention are porous or non-porous uniform inorganic microspheres, and their particle diameters are almost uniform. It includes agents, dyes, bactericides, insecticides, insect repellents, vitamins, foods, nutrients, pharmaceuticals, deodorants, liquid crystals, etc. and can be widely used in many fields.

Further, it can be used as an extender pigment in the field of anti-adhesion agents for cosmetics, paints, plastics, inks, films and the like.

Further, since it is possible to incorporate coloring substances such as pigments and dyes into uniform colored microspheres, it has an excellent effect as an additive for cosmetics, inks and plastics.

Excellent performance is expected as a packing material for high-performance liquid chromatographs and gas chromatographs, magnetic tapes, and catalysts. It can also be used as a spacer for other liquid crystals.

[0006]

2. Description of the Related Art Conventionally, a method for producing porous inorganic microspheres using a solution or the like is already known, and is disclosed in, for example, Japanese Patent Publication Nos. 54-6251 and 57-55454.

The basis of this conventional method is to mix an aqueous solution of a water-soluble inorganic compound and an organic solvent to form a W / O type emulsion, and then react with the water-soluble inorganic compound in the emulsion. Mixing with an aqueous solution that can produce a water-insoluble precipitate,
It is intended to produce porous inorganic microspheres.

This method is an extremely excellent method for producing fine porous inorganic spheres, but the size of the obtained particles, that is, the particle size, varies, and it is difficult to obtain microspheres having substantially the same particle size. Tend.

On the other hand, there have been various methods for producing emulsions, but recently, a method for producing an emulsion utilizing a microporous membrane has been developed as JP-A-2-95433.

This method is a method of producing an emulsion by press-fitting a liquid to be a dispersed phase through a microporous membrane having a uniform pore size into a liquid to be a continuous phase.

The present inventor has been researching porous inorganic microspheres utilizing the solution reaction, and as a result, as a result of applying the means for producing an emulsion using the microporous membrane to the method for producing the inorganic powder. To develop new means,
We have already filed an application (Japanese Patent Application No. 4-220679). This new technology is extremely excellent as a means for producing uniform inorganic microspheres, but the size (particle size) of the obtained microspheres is about 0.1 to 50 μm, and even more uniform particle size. There was a tendency that it was not always a suitable means for obtaining microspheres. Also, due to the inclusion of coarse particles due to the peeling of the hydrophobic membrane of the microporous membrane during manufacturing,
There was a tendency that stable manufacturing could not be performed.

[0012]

Therefore, the problem to be solved by the present invention is to develop means for producing fine spheres having a small particle size to a large particle size, that is, inorganic fine particles. The aim is to develop a method that allows for the uniform production of spheres with a small and large particle size.

[0013]

[Means for Solving the Problems] (i) Alkali metal silicates, carbonates, phosphates, sulfates, alkaline earth metal halides, and copper group element and iron group element sulfates (Ii) before or after the addition of (ii) an organic solvent to an aqueous solution containing at least one inorganic compound selected from the group consisting of, and hydrochlorides and nitrates to prepare a W / O type emulsion, (iii)
At least one of an alkaline earth metal halide, an inorganic acid, an organic acid, an inorganic acid ammonium salt, an organic acid ammonium salt, and an alkali metal carbonate, which is water-insoluble by an aqueous reaction with the inorganic compound. In the method for producing an inorganic microsphere by adding and mixing an aqueous solution of a compound capable of forming a precipitate, the aqueous solution of (i) above is added to an organic solvent through a nozzle and an electrode provided separately from the nozzle. It is solved by applying a constant voltage between the two and letting it eject.

That is, according to the research conducted by the present inventor, for example, as shown in FIG. 1, the aqueous solution (1) of the above (i) is passed through the nozzle (2) into the organic solvent (3) and the electrode (4). When the liquid is ejected while applying a voltage between the nozzle and the nozzle (2), it is possible to press the aqueous solution of (i) above into the organic solvent as uniform droplets, and at the same time, by adjusting the applied voltage, It has been found that the droplet size can be adjusted with considerable width.

If a droplet having a large particle size is to be obtained, it can be manufactured by adjusting the voltage, and a large droplet of the aqueous solution of (i) above is stably generated in the organic solvent and attracted. In addition, it was found that the target microspheres having a large particle size and a substantially uniform size can be obtained. The present invention has been completed based on this new discovery.

[0016]

The basic function of the present invention is as follows.

(A) Basically, the conventional method for producing microporous inorganic microspheres using a solution reaction should be used.

(B) At this time, as a means for preparing the W / O type emulsion, the aqueous solution of (i) above is passed through a nozzle,
That is, it is ejected and pressed into an organic solvent while applying a voltage between the nozzle and an electrode provided separately. This is a completely new finding found by the present inventor.

These will be described in order below. The conventional method can be applied as it is to the above-mentioned means (a). For example, Japanese Patent Publication No. 54-6251 and Japanese Patent Publication No. 57-55.
The method disclosed in No. 454 can be exemplified.

More specifically, alkali metal silicates, carbonates, phosphates, sulfates, alkaline earth metal halides and inorganic salts selected from sulfates, hydrochlorides and nitrates of copper group elements and iron group elements. An aqueous solution containing at least one compound and having a concentration of 0.3 mol / l to saturated is prepared.

Next, the solubility in water is preferably 5%
The following organic solvents are mixed by the above means to obtain a W / O type emulsion.

Then an alkaline earth metal halide,
At least one of inorganic acid, organic acid, ammonium salt of inorganic acid, ammonium salt of organic acid and carbonate of alkali metal
An aqueous solution of a compound which is a seed and is capable of forming a water-insoluble precipitate by an aqueous solution reaction with the above-mentioned inorganic compound (concentration: 0.
05mol / l-saturation concentration, preferably 0.1-2.0mol / l)
Is mixed with the above W / O type emulsion in an amount of the latter equivalent to 100 parts by weight of the former.

Thus, inorganic microspheres having a uniform particle size and a desired size can be obtained. The evaluation of the uniformity of the particle size of the inorganic microspheres was defined by the following formula.

Particle variation degree ε = (D90−D10) / D50

Here, D10, D50 and D90 are the particle size distribution measurement of the produced particles by the centrifugal sedimentation type absorbance method, and the cumulative amount in the cumulative particle size curve is 10%, 50%, 90.
Represents the particle size when occupying%.

Ε = 0 means that there is no variation at all, and it means that the variation increases as ε increases.

In the present invention, particles having ε smaller than about 1.3 are regarded as substantially uniform particles, and the larger the value, the more uneven the particles are evaluated.

Preferred specific examples of the organic solvent having a solubility in water of 5% or less used in the present invention are as follows.

Aliphatic hydrocarbons: n-hexane, isohexane, n-heptane, isoheptane, liquid paraffin, n-octene, isooctene, gasoline, petroleum ether, kerosene, benzine, mineral spirits, etc.

Alicyclic hydrocarbons: cyclopentane, cyclohexane, cyclohexene, cyclononane, etc.

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

Ethers: propyl ether, isopropyl ether, etc.

Halogenated hydrocarbons: methylene chloride, chloroform, ethylene chloride, trichloroethane, trichloroethylene, etc.

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, etc.

These organic solvents may be used either individually or in combination of two or more. When this W / O type emulsion is prepared, the W / O ratio of the obtained emulsion is 4/1 to 1/5, preferably about 2/1 to 1/2. The amount of the surfactant used is preferably about 10% by weight or less of the organic solvent, and particularly preferably about 0.1 to 3% by weight.

As the surfactant to be used, a nonionic surfactant is used. Preferred specific examples are as follows.

Polyoxyethylene sorbitan fatty acid ester type: polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate,
Polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan stearate, etc.

Polyoxyethylene higher alcohol ether type: polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene Nonylphenol ether, etc.

Polyoxyethylene fatty acid ester type: polyoxyethylene glycol monolaurate, polyoxyethylene glycol monostearate, polyoxyethylene glycol stearate, polyoxyethylene glycol monooleate, etc.

Glycerin fatty acid ester type: stearic acid monoglyceride, oleic acid monoglyceride, etc.

Polyoxyethylene sorbitol fatty acid ester type: tetraolein sun polyoxyethylene sorbit, etc.

Among these surfactants, polyoxyethylene sorbitan fatty acid ester-based surfactants are particularly preferable, and these are used alone or in admixture of two or more.

The present invention also includes various methods using the above-mentioned basic method, for example, various conventional methods of supporting pigments, colorants, fragrances, microorganisms and the like on the inorganic microspheres.

Further, in the present invention, JP-A-63-25 is used.
The method for producing a hollow inorganic particulate material disclosed in No. 8642 is also included in the above method (a).

This method is an inorganic material selected from alkali metal silicates, carbonates, phosphates, sulfates, alkaline earth metal halides, and sulfates, hydrochlorides and nitrates of copper group elements and iron group elements. An organic solvent is added and mixed with an aqueous solution containing at least one compound to form a W / O type emulsion,
And then at least one of an alkaline earth metal halide, an inorganic acid, an organic acid, an inorganic acid ammonium salt, an organic acid ammonium salt, and an alkali metal carbonate.
And a method for producing an inorganic microsphere having a substantially uniform particle size by adding and mixing an aqueous solution of a compound capable of forming a water-insoluble precipitate by an aqueous solution reaction with the inorganic compound,

(A) An organic solvent containing a hydrophilic surfactant is added to and mixed with an aqueous solution of the above-mentioned inorganic compound to form an O / W emulsion.

(B) The O / W emulsion thus obtained was added and mixed in an organic solvent containing a lipophilic surfactant to prepare an O / W / O mixture.
No mold emulsion, then

(C) O / W of the above (B) in an aqueous solution of a compound capable of forming a water-insoluble precipitate by the above aqueous reaction.
/ O-type emulsion is added and mixed, which is a method for producing hollow inorganic microspheres.

In the present invention, the aqueous solution of (i) above is pressed into an organic solvent. At this time, as described above, a voltage is applied between the nozzle and the electrode while the nozzle (i) above is used.
The aqueous solution of is sprayed into an organic solvent.

As shown in FIG. 1, the aqueous solution (1) of (i) is jetted from the nozzle (2) into the organic solvent (3). At this time, the nozzle (2) also serves as a kind of electrode and is ejected in a state where a voltage is applied between the nozzle (2) and the electrode (4) provided in the organic solvent (3). In FIG. 1, (5) is an inlet for the organic solvent (3). The organic solvent (3) overflows and is discharged from the discharge port (6). This FIG. 1 is a specific preferred example of the present invention. In the present invention, in principle, a device or means capable of ejecting the above aqueous solution from the nozzle while applying a voltage between the nozzle and an electrode provided elsewhere There is no particular limitation as long as it exists.

This method will be described in more detail. The electricity applied between the nozzle and the electrode is direct current. In the case of direct current, it is 0.1 to 20 KV, preferably about 1 to 5 KV.
The diameter of the nozzle is usually 0.01 to 1 mm and preferably 0.1 to 1.
The diameter is about 0.4 mm, and the material thereof may be metal or other non-insulating material, and is usually various metals such as stainless steel, brass, platinum and gold.

[0052]

EFFECTS OF THE INVENTION According to the method of the present invention, the solution reaction can be used even if the inorganic microspheres having a large particle size and a substantially uniform particle size, which have hitherto been extremely difficult to produce, have a particle size of a considerably large width Can be manufactured.

[0053]

EXAMPLES The present invention will be described in detail below with reference to examples.

[0054]

Example 1 A schematic diagram of the experimental apparatus used in this example is shown in FIG. A DC high voltage supply device was used to apply a voltage between the electrodes, that is, to the nozzle that also serves as the electrode and the ground electrode. The supply of water glass was controlled by a needle valve (KOFLOC 2412T) by pushing a pressure reduced from a nitrogen cylinder onto a tank and pushing it out. The current flowing to the ground was measured using a digital multimeter (YOKOGAWA 7544-01). The state of the generated droplets was taken with a TV camera (Panasonic WV-CL111) using a stroboscope (Sugawara MS-220) as a light source,
It was recorded with a video cassette recorder (MITSUBISHI HV-D30) and observed from a video monitor (SONY CPS-14F1).

The particle size of the generated droplets is measured by projecting a reproduced image of a video on a monitor (about 25 times) when the size is 100 μm or more, and by sampling with a dropper when the size is 100 μm or less, using an optical microscope (OLYMPUS VANOX). It was measured.

Next, the droplet generation portion is shown in FIG. The nozzle 11 is a stainless steel tube (Ito Corporation, inner diameter 18
0 μm, outer diameter 500 μm) was used. The earth electrode 12 is made of aluminum and has a disk shape with an inner diameter of 20 mm and an outer diameter of 50 mm and is placed perpendicular to the nozzle.

Water glass is water glass No. 3 (4 mol /
l) is used as a continuous phase 13 and a surfactant (span80 is 0
~ 3%) was used. Further, 15 is an earth, which is used by being housed in the vinyl tube 14. Figure 3
Medium 16, 16 '... are droplets. Also, the particle generation portion is shown in FIG.

A water glass / kerosene W / O emulsion 19 was placed using a funnel 20 in a 1.5 mol / l ammonium bicarbonate solution 18 which was stirred with a stirrer 17 (HEIDON 3000H). Then, the mixture was stirred for about 1 hour, suction-filtered, and placed in a dryer to dry.

Microspheres were manufactured as follows using the apparatus shown in FIGS.

Water glass No. 3 (4 mol / l as SiO ₂ ) was used as a continuous phase consisting of kerosene and a surfactant, and the nozzle 11 had a pressure of 1 kg / cm ² and a voltage of 800 V and a span of 8.
A W / O type emulsion is prepared by press-fitting with 0, 3%.

This was dissolved in advance at 1.5 mol /
1 liter of ammonium bicarbonate solution (1 liter) was added and reacted under stirring to separate by filtration, washed with water, washed with methanol and then at 110 ° C.
And dried for 24 hours.

Thus, almost uniform porous spherical silica fine particles having an average particle diameter of about 5 μm were obtained.

[0063]

Example 2 As in Example 1, water glass No. 3 (4 mol / l as SiO ₂ ) was used as a continuous phase in 800 ml of a toluene solution containing 15 g / l of sorbitan monolaurate as a W / O type milk. Prepare a suspension.

This was dissolved in advance at 3.0 mol /
1 liter ammonium sulphate solution 1 liter and react 2
After leaving for a while, it is separated by filtration, washed with water and washed with methanol, then 110
It was dried at ° C for 24 hours. The voltage was 500V. Thus, substantially uniform porous spherical silica fine particles having an average particle diameter of about 100 μm were obtained.

[0065]

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of an example of an apparatus used to carry out the method of the present invention.

FIG. 2 is a schematic view showing another example of an apparatus used when carrying out the method of the present invention.

FIG. 3 is an explanatory diagram showing a droplet generation portion when the present invention is carried out.

FIG. 4 is an explanatory view showing a particle generation portion when the present invention is carried out.

[Explanation of symbols]

 1 ・ ・ ・ Aqueous solution 2 ・ ・ ・ ・ ・ Nozzle 3 ・ ・ ・ ・ ・ Organic solvent 4 ・ ・ ・ Electrode 5・ ・ ・ ・ ・ ・ ・ ・ Inlet for organic solvent 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outlet

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location C08K 7/16 KCL (72) Inventor Hideyuki Yoshikawa 2-3-1 Itakano, Higashiyodogawa-ku, Osaka Suzu Wood Fat & Oil Industry Co., Ltd. (72) Inventor Yasuhiro Kikuchi 2 1-37 Itakano, Higashiyodogawa-ku, Osaka Suzuki Oil & Fat Industry Co., Ltd. (72) Inventor Masayuki Sato 2-9-12 Wakamiyacho, Maebashi, Gunma Prefecture (72) Inventor Masahiro Saito 2-353-8 Hishimachi Kiryu City Gunma Prefecture

Claims (1)

[Claims] 1. A material selected from (i) alkali metal silicates, carbonates, phosphates, sulfates, alkaline earth metal halides, and sulfates, hydrochlorides and nitrates of copper group elements and iron group elements. A solution containing at least one inorganic compound,
(Ii) before or after adding and mixing an organic solvent to form a W / O type emulsion, (iii) halides of alkaline earth metals, inorganic acids, organic acids, ammonium salts of inorganic acids, ammonium of organic acids A method for producing inorganic microspheres by adding and mixing an aqueous solution of a compound which is at least one of a salt and a carbonate of an alkali metal and can form a water-insoluble precipitate by an aqueous solution reaction with the above-mentioned inorganic compound, When the W / O type emulsion of (ii) above is prepared, a constant voltage is applied between the nozzle and an electrode provided separately through the nozzle of the aqueous solution of (i), which is a dispersed phase, in an organic solvent. A method for producing inorganic uniform fine spheres having a substantially uniform particle diameter, which comprises ejecting while adding and press-fitting the mixture into an organic solvent.