JPS63258642A - Hollow inorganic powder and grain materials and preparation of same - Google Patents

Abstract

PURPOSE:To increase the void content by adding and mixing an organic solvent to an organic solvent containing lipophilic surface active agent after being added and mixed with the water solution of inorganic compound to form O/W type emulsion. CONSTITUTION:O/W type emulsion is prepared by adding and mixing an organic solvent to water solution containing 0.5mol./l or more of silicate or the like of alkali metal. The O/W ratio is preferably O:W=1:10-3:1. Then, said O/W type emulsion is added and mixed into an inorganic solvent containing lipophilic surface active agent to prepare O/W/O type emulsion. Preferably the ratio should be 1:10-2:1. Then, the water solution of a compound to be able to form water-insoluble sediments is added to the O/W/O type emulsion mixed and reacted with to form a wall substance. The reaction time is approximately one hour or less, and water solution concentration is preferably 0.05mol./l - saturation concentration. By said process, particles of uniform film thickness can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hollow inorganic powder and a method for producing the same, and more particularly to a hollow inorganic powder having a IIIJ thickness of about 5 to 45% of the particle diameter and its production. Regarding the law.

Conventional technology One of the conventional manufacturing methods for inorganic porous powder and granular materials.
The following methods are known. That is, an organic solvent is added to and mixed with an aqueous solution containing at least one inorganic compound selected from silicates, carbonates, phosphates, and nitrates of alkali metals, and halides of alkali metals or other metals. to form an emulsion, and then at least one of alkaline earth metal halides, inorganic acids, organic acids, ammonium salts of inorganic acids, ammonium salts of n-acids, and carbonates and nitrates of alkali metals, and There is a method of producing porous inorganic powder by mixing an aqueous solution of a compound that forms a water-insoluble precipitate through an aqueous reaction with the above-mentioned inorganic compound into the above-mentioned emulsion.

This method is an extremely excellent method for producing 11-free porous particles, but in this method,
No consideration has been given to actively producing hollow inorganic porous particles.

Problems to be Solved by the Invention Accordingly, the problems to be solved by the present invention are to apply the technology of this type of conventional method to produce hollow inorganic porous fine particles, and by extension hollow inorganic fine particles with an extremely large porosity. The objective is to develop a method that can actively produce .

Means for solving the problem This problem is solved by the use of alkali metal silicates, carbonates, phosphorus M
An organic solvent is added to an aqueous solution containing at least one inorganic compound selected from salts, nitrates, and halides of alkali metals or other metals to form an emulsion, and then an emulsion of alkaline earth metals is prepared. At least one of halides, inorganic acids, organic acids, ammonium salts of inorganic acids, ammonium salts of organic acids, and carbonates and nitrates of alkali metals, and forms a water-insoluble precipitate by an aqueous reaction with the above-mentioned inorganic compounds. In the method for producing a porous inorganic powder by mixing an aqueous solution of a compound capable of forming a compound with the above emulsion, (a) an organic solvent is added to and mixed with the aqueous solution of the inorganic compound to form an O/W emulsion. (b) The 0/W type emulsion obtained here is added and mixed into an organic solvent containing a lipophilic surfactant to form a 0/W/O type emulsion, and then (c) the above water soluble This problem can be solved by adding and mixing the O/W/O emulsion described in (b) above into an aqueous solution of a compound capable of forming a water-insoluble precipitate through a chemical reaction.

As stated above, the main features of the structure and action of the invention are as follows: (a)
Add and mix an organic solvent to the aqueous solution of the above inorganic compound and O/
(b) The O/W emulsion obtained here is added and mixed into an organic solvent containing a lipophilic surfactant to form an O/W/O emulsion, and then ( c) Adding and mixing the O/W/O type emulsion of (b) above into an aqueous solution of a compound capable of forming a water-insoluble precipitate by the water-soluble reaction.

More specifically, when preparing an emulsion by adding and mixing an organic solvent to at least one aqueous solution of the above inorganic compound,
In the conventional method, a W/O type emulsion is made, but in the present invention, as described in (a) above, this is made into an 0/W type emulsion. Next, this O/W type emulsion is added and mixed into an organic solvent containing a lipophilic surfactant as described in (0) above to obtain an O/W/O type emulsion. That is, in the step (a), as shown in Figure 1, the organic solvent (2) is dispersed in the form of droplets in the aqueous solution (1) of the inorganic compound, and this is treated as in (b) above. As a result, as shown in Fig. 2, droplets of an aqueous solution (1) of an inorganic compound in which the organic solvent (2) is embedded in the organic solvent (3) are generated, and the O/W/O It becomes a type emulsion.

Such an O/W/O type emulsion is then added to an aqueous solution of a compound capable of forming a water-insoluble precipitate by a water-soluble reaction according to the step (c) above, and is added to the interface between the droplets and the aqueous solution. A reaction takes place to form a water-insoluble precipitate material, the so-called wall material. Figure 3 shows this state, and (4) in Figure 3 is a wall? 5, and fine particles in which the organic solvent (1) is encapsulated in the wall material (4) are generated. At this time, the wall material itself produced by the aqueous reaction is porous, and therefore, in the fine particles of the present invention, the wall material itself is porous, and the organic solvent inside must be volatilized by an appropriate means. As a result, the inside becomes hollow, and its porosity becomes extremely large.

On the other hand, in the conventional method, a W/O emulsion is prepared from an aqueous solution of a reactive inorganic compound and a 41-organic solvent, and this is mixed with the aqueous solution of the wall material forming compound. The shape does not include the organic solvent, and hollow particles are difficult to form.

However, even in the conventional method, the reaction occurs at the interface between the droplet and the aqueous solution, which is the same as in the method of the present invention, and the inorganic compound in the droplet reacts with the wall-forming substance to form the wall. Inorganic compounds in the droplet are consumed in this reaction, sometimes creating voids inside the droplet, but the difference between this conventional method and the method of the present invention is that the hollow formation process is fundamentally the same as explained above. They are different.

The method of the present invention will be explained below in the order of its manufacturing steps.

First, an aqueous solution containing at least one inorganic compound selected from silicates, carbonates, phosphates of alkali metals, nitrates, alkaline earth metals, or other halides, preferably at a concentration of 0.5 mol/min or more. Particularly preferably, an organic solvent is added to and mixed with an aqueous solution having a concentration of 3.0 mol/liter to saturation to prepare an O/W emulsion (step (a) above). As the organic solvent in this case, any organic solvent that has been conventionally used in this type of method can be used, and preferred ones are those that are liquid at room temperature, have a solubility in water of 8% or less, and are not substantially involved in the reaction. I can do it.

Preferred specific examples of these are as follows.

Aliphatic hydrocarbons: n-hexane, isohexane, n-hebutane, isohbutane, n-octane, isooctane, gasoline, petroleum ether, kerosene, benzine, mineral spirits, etc. Alicyclic hydrocarbons dichloropentane, Aromatic hydrocarbons such as cyclohexane, cyclohexene, and cyclononane: Benzene, triene, xylene, ethylbenzene, propylbenzene, cumene, mesitylene, tetralin, styrene, etc. Ethers: Probyl ether, isopropyl ether, etc. Halogenated hydrocarbons: Methylene chloride, Oo form, ethylene chloride, trichloroethane, trichloroethylene, etc., esters: ethyl acetate, -propyl acetate, isopropyl acetate,
n-butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, butyl lactate, methyl propionate,
These organic solvents, such as ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, and butyl butyrate, can be used alone or in combination of two or more.

When producing this O/W type emulsion, a surfactant is usually used. Further, the O/W ratio at this time is not particularly limited as long as the obtained emulsion is O/W type, but O:W-
The ratio is preferably about 1:/O to 3:1. The amount of surfactant to be used is preferably about /O% or less of the organic solvent, especially
, oi to about 3% by weight is preferred.

Although a wide range of conventional surfactants can be used as the surfactant, preferred specific examples are as follows.

Sorbitan fatty acid esters: sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan sekisoleate, etc.

Polyoxyethylene rubitan fatty acid esters: polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, polyoxyethylene sorbitan monooleate, poly Polyoxyethylene higher alcohol ethers such as oxyethylene sorbitan stearate: polyoxyethylene lauryl ether, polyoxyethylene cedyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene octylphenol ether, polyoxyethylene Nonylphenol ether, etc., polyoxyethylene fatty acid esters: polyoxyethylene glycol monolaurate, polyoxyethylene glycol monolaurate, polyoxyethylene glycol stearate, polyoxyethylene glycol monooleate, etc., glycerin fatty acid esters, nistearic acid Monoglyceride, oleic acid monoglyceride, etc. Polyoxyethylene sorbitol fatty acid ester type: Tetraoleic acid polyoxyethylene sorbitol, etc. These surfactants are used alone or in combination.

Next, in the present invention, this O/W emulsion is added and mixed into an organic solvent containing a lipophilic surfactant to form an O/W/O emulsion.
Prepare a mold emulsion (step (b)). At this time, there are 8!
An appropriate solvent may be used within the same range as above, and may be the same as in step (a) or a different type of organic solvent. Further, as the surfactant, a lipophilic one is used, and its preferred specific example is almost the same as that in the above step (a), and the amount used is also within the same range as in the step (a). The O/W/O ratio is O/W:0-1:
/O to about 2:1 is preferred.

Next, in the present invention, in the above 0/W/○ type emulsion,
An aqueous solution of a compound that forms a water-insoluble precipitate is added and mixed and allowed to react to form a wall material. Although this reaction proceeds well at normal temperature and normal pressure, the reaction may be accelerated under heating. The reaction time varies depending on the concentration and blending ratio, but
Usually it takes about 1 hour or less. The concentration of the above aqueous solution is 0.0
The concentration is preferably 5 mol/9t to saturation, particularly preferably about 0.1 to 2 mol/J2.

The reaction product is filtered, washed with water, and dried to yield 1 q of hollow porous inorganic powder.

The powder and granules obtained by the method of the present invention are hollow, and the film thickness of the wall material is usually about 5 to 45% of the particle diameter, and the wall material itself is also porous, making it extremely porous as a whole. It is.

Effects of the Invention The method of the present invention as described above ensures that the wall thickness is 50% of the particle diameter.
-45% spherical hollow porous powder +Fi. This product is a hollow sphere with a porosity of up to 96% and is extremely useful for encapsulating fragrances, deodorants, pigments, insecticides, disinfectants, rust preventives, etc.

Example The present invention will be explained in more detail with reference to Examples below.

Example 1 (Production method of hollow porous spherical silica) Water glass No. 1 (4 mol/l2 as SiO□) 500
A 2% ethyl acetate solution of polyoxyethylene (n-/O) lauryl ether was added to d and stirred at high speed to prepare an O/W emulsion.

This was added to 200 Od of polyoxyethylene lauryl ether 3% ethyl acetate solution, stirred at high speed, and O/W/
An O-type emulsion was prepared.

The O/W/O type emulsion obtained in this way was 1
The mixture was added to 3,000 mol/mol of ammonium sulfate and reacted with stirring, left for 2 hours, filtered and separated, washed with water and dried to evaporate ethyl acetate within the porous particles. In this way, hollow porous spherical silica fine particles 1/Og having a particle diameter of 1 to 0 μm and a film thickness of about 8% based on the particle diameter were obtained. A scanning electron micrograph of this product at a magnification of /O000 is shown in FIG.

Example 2 (Production method of hollow porous spherical magnesium silicate) Water glass 3
200 m of a 2.5% toluene solution of polyethylene ethylene (n-/O) nonyl phenyl ether was added to 500 d of No. (SiO15T Nil/A) and stirred at high speed to prepare an O/W emulsion I. This is polyoxyethylene (n
-3) Nonylphenyl ether 3% toluene solution 15
00d and stirred at high speed to form an O/W/O type emulsion.
manufactured.

The product obtained in this way was added to 0.5 mol/6000 g of parent magnesium chloride aqueous solution, stirred, and reacted. After being allowed to stand for 3 hours, it was filtered and washed with water to remove reaction by-products such as sodium chloride. It was removed and further dried to evaporate the toluene inside the hollow. Thus the particle size is 1-15μ
Hollow porous spherical magnesium silicate 250Q having a film thickness of about 5% of the particle diameter was obtained at dawn.

Example 3 (Production method of hollow porous calcium carbonate) 1 g of polyoxyethylene (n-/O) nonyl phenyl ether was added to a 4 mol/fJ potassium carbonate aqueous solution 300-, and 50-benzene was added and stirred at high speed. Then, an O/W type emulsion was manufactured by vA.

This product was added to 800 d of a 3% xylene solution of polyoxyethylene (n-3) nonylphenyl ether and stirred at high speed to produce an O/W/O type emulsion.

The mixture was added to 12,000 d of a 0.2 mol/R calcium chloride aqueous solution, stirred, and left to react for 30 minutes.

This was separated by filtration, washed with water to remove potassium chloride as a reaction by-product, and dried to evaporate the xylene inside. Thus, the hollow porous calcium carbonate 11 has a particle size of 1 to 0 μm and a film thickness of about 18% of the particle size.
5g was obtained.

Example 4 (Production method of hollow porous basic magnesium carbonate) 3 mol/
Mulberry potassium carbonate aqueous solution 200ai! , polyoxyethylene (n-30>sorbitan trioleate 1.5%
Add 50 d of cyclohexane solution and stir at high speed, O/W
A mold emulsion was prepared. This was added to 600 rR1 of a 3% sorbitan monolaurate solution in cyclohexane and stirred at high speed to produce a 0/W/O type emulsion.

The emulsion thus obtained was added to 0.3 mol/6000 ml of aqueous solution of magnesium chloride, stirred, reacted, and left for 1 hour.

This was filtered, further washed with water, and dried to obtain 70 g of hollow porous spherical basic magnesium carbonate having a particle size of 0.5 to 15 μm and a film thickness of about 12% of the particle size.

Example 5 (Production method of hollow porous barium sulfate) 3 mol/liter ammonium sulfate aqueous solution 300 #If! , polyoxyethylene (diethylene oxide group-9)
T? 50 Id of a 2% hexene solution of candary alcohol ether was added and stirred at high speed to prepare an O/W emulsion.

This was mixed with sorbitan monostearate 3% hexene solution/
The mixture was added to O00d and stirred at high speed to produce an O/W/O type emulsion.

The product thus obtained was added to 5,000 d of a 0.5 mol/liter aqueous barium chloride solution, stirred, reacted, and left for 1 hour.

This is separated by embroidery, further washed with water, dried, and the particle size is 1 to 1.
205 ml of hollow porous spherical barium sulfate having a thickness of 20 μm and a film thickness of about 14% was obtained.

[Brief explanation of the drawing]

FIGS. 1 to 3 are drawings simulating the dispersion state of the emulsion produced when carrying out the method of the present invention. Further, FIG. 4 is a scanning electron micrograph of the granular material of Example 1 at a magnification of /O000. 1...Aqueous solution of inorganic compound, 2...Organic solvent 3...Organic solvent 4...Wall material (and above)

Claims (2)

[Claims] (1) A hollow inorganic powder or granule in which the original film is 5 to 45% of the particle diameter and the material forming the wall is porous. (2) Adding an organic solvent to an aqueous solution containing at least one inorganic compound selected from silicates, carbonates, phosphates, and nitrates of alkali metals, and halides of alkali metals or other metals. Mix to make an emulsion,
Next, an aqueous solution reaction with at least one of alkaline earth metal halides, inorganic acids, organic acids, ammonium salts of inorganic acids, ammonium salts of organic acids, and carbonates and nitrates of alkali metals, and the above-mentioned inorganic compound. In a method for producing a porous inorganic powder by mixing an aqueous solution of a compound capable of forming a water-insoluble precipitate with the emulsion, (a) an organic solvent is added to and mixed with the aqueous solution of the inorganic compound; (b) The O/W emulsion obtained here is added and mixed into an organic solvent containing a lipophilic surfactant to make an O/W/O emulsion. , and then (c) hollow inorganic powder particles characterized in that the O/W/O type emulsion of (b) above is added and mixed into an aqueous solution of a compound capable of forming a water-insoluble precipitate by the water-soluble reaction. How the body is manufactured.