JP2002037645A - Fine hollow aluminosilicate glass ball and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fine hollow aluminosilicate glass ball which has a fine diameter and low spherical aberration and low density and high strength. SOLUTION: This is a fine hollow glass ball manufactured by heating of slurry droplet obtained by wet pulverization of blended raw materials of aluminosilicate glass. The glass ball has an average particle diameter of 1-20 μm, an average particle density 0.20-1.50 g/cm3, the degree of true ball 1<=(length of long axis/length of short axis)<1.2 and a strength of over 10% at 10% breaking by volume based on equation 16.7×E×(t/2a)n (n=2.5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fine hollow aluminosilicate glass sphere and a method for producing the same.

[0002]

2. Description of the Related Art Micro hollow glass spheres are generally called glass micro-balloons (hollow bodies) and have a lower specific gravity, heat resistance, pressure resistance and impact resistance than other fillers. When used as a filler, physical properties such as dimensional stability and moldability of the filler can be improved. For this reason, many plastic molding parts such as automobiles, portable electronic devices and home appliances, putties, sealing materials, buoyancy materials for ships, synthetic wood, reinforced cement outer wall materials, lightweight outer wall boards, artificial marble, etc. Used for applications.

In addition, sound insulation materials, sound absorption materials, heat insulation materials, insulation materials,
It is a material that is expected to be developed for various uses, such as a material having a low dielectric constant. In particular, applications expected to be expanded by miniaturization include use in heat-insulating paints for heat insulation applications, and wire coating materials and substrates for low dielectric constant applications. It can also be used for applications such as hydrous explosives, paper clay, rubber, and paints. Thus, the micro hollow glass sphere has a wide range of applications,
Accordingly, in recent years, there has been a strong demand for better fine hollow glass spheres.

[0004] Various proposals have already been made for a fine hollow glass spherical body and a method for producing the same. For example, JP-A-58-155551 discloses SiO ₂ , H ₃ BO
₃ , CaCO ₃ , Na ₂ CO ₃ , NH ₄ H ₂ PO ₄ , Na ₂ SO
Raw materials such as ₄ are melted at a high temperature of 1000 ° C. or more to form a glass containing a large amount of sulfur, and then the glass is dry-pulverized, and the glass fine powder obtained by classification is dispersed in a flame. A method is described in which a borosilicate glass fine hollow spherical body is formed by causing a sulfur component to foam as a foaming agent component by allowing the sulfur to stay. In addition, 4-370
No. 17 describes a method for obtaining a fine hollow glass spherical body by firing a fine powder in which a glass forming component and a foaming agent component are supported on silica gel in a furnace.

In these methods, dried glass fine powder is dispersed in high-temperature hot air, whereby the glass is heated and the viscosity of the glass is reduced, and gas is generated from the foaming agent component by thermal decomposition. Therefore, the particle shape becomes spherical due to surface tension, and at the same time, it becomes hollow due to the generated gas in the particle.

However, in such a conventional technique, since the dried glass fine powder is dispersed in hot air at a high temperature, the glass powder is liable to agglomerate as the size becomes smaller.
Some particles are fused together when the glass is melted, so it is possible to obtain hollowness sufficient to impart a lightening effect or heat insulating effect, but it is difficult to obtain a fine hollow glass sphere with a fine diameter and uniform particle size Met.

[0007] Japanese Patent Publication No. 4-50264 discloses a method for producing a fine hollow glass sphere made of aluminosilicate glass, in which a volcanic glassy deposit having a particle diameter of 20 μm or less is prepared in a hydrochloric acid solution or a sulfuric acid solution. After heating and keeping the composition for 8 hours or more to make the composition of the surface layer of the particles different from the composition of the inside of the particles, heat treatment is performed at a temperature of 900 to 1100 ° C. for 1 second to 1 minute, and thereafter, floating separation in air or air classification. A method is described. But with this method,
Sufficient sphericity cannot be obtained due to the foaming operation in the low-temperature range as the glass composition, and the glass composition has sufficient strength, in particular, the strength of a 10% by volume decay as described below is less than 5%. Was not obtained.

Japanese Patent Application Laid-Open No. 6-154586 describes a method of using a particulate material having a large ignition loss, such as a volcanic vitreous material such as shirasu on which aluminosilicate glass is formed. In this method, the average particle size is 2
Although a micro glass hollow body of 0 μm or less can be obtained, the raw material is hollowed out only by heat treatment, and it was still difficult to obtain a glass having a low particle density and sufficient strength. Further, sodium is easily eluted from the composition of aluminosilicate containing a large amount of sodium represented by a hollow body of shirasu, and there is a limitation particularly for electronic materials.

[0009] Further, in each of these, the ground primary particles are made into a hollow body as a single particle, and there is no concept of granulating the finely ground primary particles into a hollow body.
It is generally accepted that when heated and melted, the outer surface is maintained without melting and the internal foam is maintained without rupture, resulting in a hollow body. Was to be processed.

Therefore, the fine particles excessively pulverized by the fine pulverization are essentially discarded without being recycled, the yield of foaming is reduced depending on the shape of the pulverized particles, or the particles after foaming are broken. There were also problems such as easy hole formation, a surface treatment step, and a step of classifying the raw material before foaming after pulverization.

On the other hand, Japanese Patent Application Laid-Open No. 9-124327 discloses
Describes a method in which a slurry of a glass preparation raw material obtained by wet-grinding a glass preparation raw material containing a foaming agent is formed into droplets, which are heated to be vitrified to obtain a fine glass hollow body. The micro glass hollow body obtained by this method,
Fillers such as resins and paints are useful because the surface and painted surface of the resin molded product are smooth, but are not sufficient in terms of collapse strength and heat resistance depending on the use conditions.

Further, the glass raw material used also brings about the composition of borosilicate glass, soda-lime glass and zinc phosphate glass, and a glass hollow body having high heat resistance and a glass hollow body suitable for electronic materials are used. I couldn't get it.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the production process and the product quality in the prior art, and to obtain a fine particle, high sphericity, low density and high strength. An object of the present invention is to efficiently provide a hollow glass sphere having a higher heat resistance than a micro hollow glass sphere such as a borosilicate glass based on natural or synthetic inexpensive raw materials.

[0014]

According to the present invention, an average particle size on a volume basis is 1 to 20 μm, and an average particle density is 0.20 to 20 μm.
1.50 g / cm ³ , the sphericity is in the range of 1 ≦ (length in the long axis direction / length in the short axis direction) <1.2, and the composition is SiO 2 in mass%.
₂ is 30 to 85% Al ₂ O ₃ is 6-45%, alkali metal oxides is 0-30%, alkaline earth metal oxides 0
30%, B ₂ O ₃ is hollow glass microspheres made of 0 to 1%, and 10 volume% strength decay formula 16.7 × E
× (t / 2a) 10 of theoretical strength given by ^2.5
% Or less, and a minute hollow aluminosilicate glass sphere characterized by being at least 0.1% by weight.

Here, E is the Young's modulus (unit: GPa) of the glass constituting the hollow micro glass body, t is the thickness (unit: mm) of the shell of the hollow glass body, and a is the hollow portion of the micro hollow glass sphere. It is a radius (unit: mm).

Further, the present invention provides a raw material slurry having an average particle diameter of 2 μm or less by wet pulverizing a glass blended raw material,
The present invention also provides a method for producing the above-mentioned fine hollow aluminosilicate glass spheres which is vitrified and formed into fine hollow glass spheres by turning the slurry into droplets containing a blended raw material and heating the droplets.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The fine hollow aluminosilicate glass sphere of the present invention has a fine particle diameter as described above.
Low density, high sphericity and high strength. First, the particle diameter is 1 to 20 μm as a volume-based average particle diameter. Preferably it is 3 to 15 μm. The volume-based average particle diameter can be measured with a laser scattering particle size analyzer (for example, Microtrack HRA model 9320-X100 manufactured by Nikkiso Co., Ltd. used in the examples).

When the average particle size exceeds 20 μm,
When used as an interlayer insulating layer material for a multilayer substrate or a filler for a resist material, it cannot be contained within a predetermined layer thickness, and there is a high possibility that various problems such as short-circuiting of a conductive portion will be caused. Those having a particle diameter of less than 1 μm have an average particle density of 1.50.
g / cm ³ , and the expected function is not exhibited.

Next, the particle density is 0.20 to 1.50 g.
/ Cm ³ . Preferably 0.20 to 0.70 g / c
m is ^3. The particle density can be measured by a helium gas replacement dry automatic densitometer (for example, Acupic 1330 manufactured by Shimadzu Corporation used in the examples). Is less than the particle density of 0.20 g / cm ^3, the collapse strength without weak practicality, if it exceeds 1.50 g / cm ^3, sufficient weight reduction, thermal insulation effect, a low dielectric constant effect, soundproof Etc. cannot be given.

Next, although having a shape, the hollow body of the present invention is substantially spherical and formed of a single foamed sphere, and is observed by a scanning electron microscope (hereinafter referred to as SEM) photograph by visual observation. The surface properties are smooth, and almost no pierced hollow body is observed. As a specific sphericity, when expressed as an aspect ratio of (length in the major axis direction / length in the minor axis direction)
The range is 1 ≦ (length in the long axis direction / length in the short axis direction) <1.2. When (length in the major axis direction / length in the minor axis direction) ≧ 1.2, the desired strength is not exhibited, and dimensional stability cannot be maintained when a composite material such as a molding compound is used.

Further, the fine glass sphere of the present invention has
The strength of the volume% decay is given by the formula 16.7 × E × (t / 2a)
More than 10% for the theoretical strength given by ^2.5 . It is preferably at least 15%. Here, the strength of the 10% by volume collapse is determined by measuring the pressure required for 10% by volume collapse when a hydrostatic pressure is gradually applied to the micro-diameter hollow glass sphere. That is, the glass microspheres are dispersed in glycerin, and two or more arbitrary different pressures are applied by a pressure tester (for example, manufactured by Microtech Nithion Co., Ltd. used in the examples), and before and after the pressure application. Is calculated from the specific gravity difference, and the volume% of the collapsed minute hollow glass sphere is calculated to be 10% by volume based on the calculated value.
Is determined by extrapolating the applied pressure necessary to collapse

Here, the Young's modulus is measured by a resonance method, and the unit is GPa. In addition, the thickness of the shell and the radius of the hollow portion of the glass hollow body are values calculated from the average particle diameter measured by a laser scattering type particle size analyzer and the average particle density measured by a dry automatic densitometer. mm.

If the strength of the 10% by volume collapse is less than 10%, the material tends to be broken when an excessive stress is generated in a processing step such as kneading, and has a light weight effect, heat insulation effect and low dielectric constant sufficient for the intended use. It will not be possible to exhibit the efficiency effect.

The reason why the micro glass hollow body having a high strength of 10% by volume collapse realized in the present invention is obtained as compared with the conventional method of dispersing and retaining raw material powder in a flame. Then, by pulverizing the glass raw material mixture in a flammable liquid, and heating the slurry as droplets, at a sufficiently high temperature and a short residence time, granulation, melting,
It is presumed to be foamed.

The micro hollow glass sphere of the present invention comprises:
The glass composition is made of aluminosilicate glass. The composition of the minute hollow glass sphere is SiO _{2 in} mass%.
But 30 to 85% Al ₂ O ₃ is 6-45%, alkali metal oxides is 0-30%, alkaline earth metal oxides 0-3
0%, B ₂ O ₃ is 0 to 1%. When the content of SiO ₂ is less than 30%, the chemical durability of the glass is deteriorated.
%, The viscosity of the glass is so high that a large amount of heat is required at the time of foaming. SiO ₂ is 40 to 80
% Is more preferable.

If the content of Al ₂ O ₃ is less than 6%, the chemical durability of the glass is deteriorated, and if it exceeds 45%, the melting property is reduced, so that each is unsuitable. Al ₂ O ₃ is 10
More preferably, it is 40%.

Alkali metal oxides (Na ₂ O, K ₂ O, L
If i ₂ O exceeds 30%, alkali elution occurs, causing a decrease in electrical insulation. It is preferable that the amount is as small as possible. More preferably, the content of the alkali metal oxide is 2 to 25%.

Alkaline earth metal oxides (CaO, Mg
O, BaO, SrO) may lead to devitrification of the glass if it exceeds 30%. The amount is preferably as small as possible as in the case of the alkali metal oxide. More preferably, the content of the alkaline earth metal oxide is 2 to 25%.

If B ₂ O ₃ is more than 1%, when used as a filler for electronic materials, there is a possibility that the electric insulating property is lowered, which is not preferable, and boron is eluted even in cosmetics applications. That is not preferred.
Further preferred if B ₂ O ₃ is from 0 to 0.2%.

For components other than SiO ₂ , Al ₂ O ₃ , alkali metal oxides, alkaline earth metal oxides and B ₂ O ₃ , fine hollow aluminosilicates such as P ₂ O ₅ , Fe ₂ O ₃ and TiO ₂ The glass component in the glass sphere is not particularly limited, but is preferably kept as small as possible from the viewpoint of maintaining heat resistance and collapse strength, and is generally preferably 5.0% or less.

By selecting a raw material having a low content of uranium and thorium, it is possible to obtain a fine hollow glass sphere having a low emission amount of alpha rays and suitable as an electronic material.

Although the minute hollow aluminosilicate glass sphere of the present invention has such excellent properties as described above, as described above, usually, the glass component preferably contains an alkali metal oxide. N
If a large amount of an alkali metal oxide such as a ₂ O is contained, the use of the filler may be insufficient in some applications, especially as a filler for electronic material members in which sodium elution is extremely difficult, despite its excellent performance. Limited.

In the present invention, in order to solve such a problem, as a more preferred embodiment of the fine hollow aluminosilicate glass sphere, silica (Si
An O ₂ ) film is provided. Those having a silica film formed on the surface can prevent sodium from being eluted from the surface and can be used more widely for electronic material members.

Various methods are conceivable for forming a silica film on the surface, but an effective and easy method is to use an organic substance containing a silicon element such as perhydropolysilazane. That is, such a compound solution may be coated on the surface of a glass spherical body by spraying or the like, and then dried and fired, and then converted to silica. The silica film is effective even if it is extremely thin, and a certain effect can be obtained even if it is not necessarily formed all over the surface of the glass spherical body.

[0035] The fine hollow aluminosilicate glass sphere according to the present invention as described above has the following advantages.
It also has improved light weight, heat resistance, pressure resistance, and impact resistance, and has the effect of improving physical properties with excellent dimensional stability and moldability. Molding compounds such as automobiles, portable electronic devices and home appliances, putty and sealing materials, marine buoyancy materials, synthetic wood, reinforced cement exterior wall materials, lightweight exterior wall boards, artificial marble, etc. And the like.

The present invention can be applied to various uses such as a conventional sound insulating material, a sound absorbing material, a heat insulating material, an insulating material, a material having a low dielectric constant. In particular, applications that are expected to be further expanded by miniaturization can be used in heat-insulating coatings for heat-insulating applications, and wire coating materials and substrates for low-dielectric constant applications.

When the minute hollow glass sphere is used as a filler for the resin, the resin may be unsaturated polyester, epoxy, vinyl chloride, SBR latex, acrylic emulsion, polyurethane, silicone, phenol, polypropylene, polyester, fluorine, or the like. Resin is exemplified.

In addition, since they are spherical and hollow particles, they provide excellent texture such as elongation when applied to the skin, and have good sensibility and aesthetics on soft and elastic skin, and therefore, such as foundations. It can also be used very suitably as a cosmetic compounding filler.

Next, the production method of the present invention will be described. The glass blending raw material in the present invention is vitrified by heating, and is preferably a volcanic glassy sediment or zeolite that loses weight by ignition. The present invention provides a synthetic or natural raw material having a loss on ignition or a mixture thereof, more preferably a mixture to which an inorganic substance generating a gas by heating is added so as to express a predetermined composition, and Is prepared by wet-pulverizing these raw materials in a flammable liquid such as alcohol, kerosene, light oil, or heavy oil to prepare a slurry containing a raw material powder having an average particle diameter of 2.0 μm or less, and spraying the slurry. By doing so, fine droplets containing the raw material are formed, and then the droplets are heated to vitrify and form a fine hollow glass sphere.

The production method of the present invention will be described in detail below. As the volcanic glassy deposit used as a raw material, natural volcanic glass such as shirasu, obsidian, perlite and pine stone can be preferably used. These are produced in Kyushu and Hokkaido, and the secondary sediment, especially in Yoshida-cho, Kagoshima Prefecture, can be preferably used because it is effective in reducing the true density of the obtained fine hollow glass spheres.

As the zeolite, zeolite 3A, zeolite 4A, zeolite 5A having loss on ignition,
Any of synthetic or natural products such as zeolite X, zeolite Y, zeolite L, zeolite P, zeolite AZM, faujasite type zeolite, natural zeolite and the like can be used.

Natural or synthetic minerals having a loss on ignition, such as bentonite and allophane, can also be used. However, from the availability of hollow bodies and the physical properties of the products, and the availability of inexpensive raw materials having a stable composition, shirasu and obsidian are used. , Perlite, pinestone, and zeolite are preferred. In the case of producing a fine hollow glass spherical body using these raw materials, it is effective to further add an inorganic substance that generates a gas component by heating.

As a preferable inorganic substance to be added, Na ₂
SO ₄ , Na ₂ CO ₃ , NaNO ₃ , K ₂ SO ₄ , K ₂ CO ₃ ,
Sulfates, carbonates, nitrates of alkali metals such as KNO ₃ , Li ₂ SO ₄ , Li ₂ CO ₃ , LiNO ₃ , CaSO ₄ , C
aCO ₃ , Ca (NO ₃ ) ₂ , MgSO ₄ , MgCO ₃ , M
g (NO ₃ ) ₂ , BaSO ₄ , BaCO ₃ , Ba (NO ₃ ) ₂
Gas components such as carbon dioxide, sulfur oxides, and nitrogen oxides are generated by heating alkaline earth metal sulfates, carbonates, nitrates, etc., and silicon carbides and nitrides, aluminum carbides and nitrides, etc. The following is an example. Further, a substance having a hydrate such as bound water and generating steam by heating can be applied, and is selected according to the required quality of the hollow body to be obtained.

The wet pulverization of the raw material is suitable when a flammable liquid is sprayed and heated later as a liquid used in the wet pulverization. In particular, it is preferable to use the same slurry liquid as the working process is simplified. Examples of the flammable liquid include alcohols such as methanol, ethanol, and isopropyl alcohol, ethers, kerosene, light oil, and heavy oil. This liquid may be a mixture thereof, and may further contain another liquid, for example, water.

For dispersing the slurry and stabilizing the dispersion, a dispersant and a dispersion stabilizer may be added. As the dispersant, a nonionic surfactant, a cationic surfactant, an anionic surfactant, a polymer surfactant, or the like can be used. Among them, a polymer anionic surfactant is preferable,
For example, an acid-containing oligomer such as a copolymer of acrylic acid and an acrylic ester having a large acid value of about 5 to 100 mgKOH / g is preferable. Such a polymer anionic surfactant is advantageous because it contributes to dispersion of the slurry and stabilization of the dispersion state, and also can suppress the viscosity of the slurry to a low level.

The working process can be simplified if the amount of the liquid is adjusted so that the concentration of the mixed raw material powder in the liquid in the wet pulverization process is the same as the concentration of the glass mixed raw material in the slurry required at the time of spraying. Is preferred. The wet grinding machine to be used is preferably a medium stirring mill represented by a bead mill from the grinding speed and the attained particle size, but a ball mill, a mill,
A wet pulverizer such as an ultrasonic pulverizer or a high-pressure fluid static mixer may be used. Contamination from the material of the crusher reduces the yield and strength of the fine hollow glass spheres depending on the composition and the amount of contamination, so the material of the liquid contact part is selected from alumina, zirconia, and alumina and zirconia composite ceramics. It is desirable to do. Further, a material having a composition similar to that of the raw material may be used.

When the average particle diameter (based on volume) of the glass-mixed raw material after the wet pulverization exceeds 2.0 μm, particularly when a plurality of raw materials or a recycled product removed by classification or flotation are prepared, It is difficult to obtain a minute hollow glass sphere having a uniform composition. The average particle size of the glass preparation raw material after the wet pulverization is more preferably in the range of 0.01 to 1.0 μm.

In the case where a raw material having a large particle diameter is contained in the glass pulverized raw material that has been wet pulverized, the raw material may be classified in a wet state and a glass having a predetermined particle diameter may be selected and used.
Even if crushed to an average particle diameter of 0.01 μm or less, if the concentration and viscosity of the slurry are adjusted, there is no problem in the subsequent operation,
Equipment for grinding and power consumption are excessive, which is not preferable for industrial mass production.

When the glass blended raw material thus obtained does not have a predetermined concentration as a slurry, a shortage of liquid is added to adjust the glass blended raw material to a predetermined concentration. If the concentration of the prepared raw material in the slurry is too low, the productivity is reduced, and if the concentration is too high, the viscosity of the slurry is increased and handling becomes inconvenient, and aggregation occurs to form a hollow glass sphere having a large particle size. The concentration of the glass blending raw material in the slurry is preferably in the range of 5 to 50% by mass, particularly preferably 10 to 40% by mass.

Next, the slurry is converted into droplets. The droplets contain a glass blending raw material. As a method of generating such a droplet, a method of forming a droplet by pressurized spray, a method of forming a droplet by ultrasonic waves, a method of forming a droplet by centrifugal force,
A method of forming droplets by static electricity is exemplified, but a method of forming droplets by pressurized spray is preferable in terms of productivity. The following two methods are exemplified as a method of forming droplets by pressurized spray.

The first method for producing droplets is a method in which a two-fluid nozzle is used to form droplets at a gas pressure of 0.1 to 2 MPa. At this time, if the gas pressure is less than 0.1 MPa, the effect of the fine gas droplets by the propellant gas is too low, the particle diameter of the fine hollow glass spherical body is too large,
It is difficult to obtain the desired particle size. On the other hand, if the gas pressure exceeds 2 MPa, combustion becomes unstable and misfiring easily occurs, and equipment and power for pressurization become excessive, which is inconvenient for industrial implementation.

Examples of such gas include air, nitrogen, oxygen,
Any of carbon dioxide and the like is suitably used, but from the viewpoint of controlling the combustion temperature and obtaining a fine hollow glass spherical body having a good surface smoothness, the oxygen concentration is preferably 30% by volume or less. This is to suppress the burning of the slurry before the dropletization is completed in the spray granulation process, and to control the droplet to burn after the dropletization is completed and the predetermined droplet is formed. It is. As a result, the particle size distribution of the droplets becomes fine and sharp, and as a result, the particle size distribution of the hollow body becomes fine and sharp, and a lightweight hollow body can be obtained in high yield.

The second method of producing droplets is to add 1-8
This is a method of applying a pressure of MPa and spraying to form droplets. If this pressure is less than 1 MPa, the particle diameter of the fine hollow glass sphere becomes too large, and it is difficult to obtain a target particle diameter. On the other hand, if this pressure exceeds 8 MPa, combustion becomes unstable and misfiring easily occurs, and equipment and power for pressurization become excessive, which is inconvenient for industrial implementation.

The produced droplets contain a glass-mixed raw material having a desired composition. If the size of the droplet is too large, combustion becomes unstable, large particles are generated, or the droplet explodes during burning or heating, resulting in an excessively fine powder, which is not preferable. If the granulated material composed of the pulverized raw material powder is too small, the obtained glass composition is difficult to be uniform, and the yield of the fine hollow glass spheres is not preferable. Preferred droplet sizes are in the range of 0.1 to 70 μm.

The droplets are heated to melt the glass-mixed raw material and vitrify, and the foaming component in the glass is further gasified to form a fine hollow glass sphere. As the heating means, any means such as combustion heating, electric heating and induction heating can be used. The heating temperature depends on the temperature at which the glass mixture raw material is vitrified. Specifically, 800 to 17
It is in the range of 00 ° C. In the present invention, the most preferable means is that the liquid component of the slurry is a flammable liquid,
The combustion generates heat to melt and foam the glass.

The formed fine hollow glass spheres are recovered by a known method such as a method using a cyclone, a bag filter, a scrubber or a packed tower.

Further, the unfoamed product in the recovered powder is removed, and only the foamed product can be recovered by the flotation separation method using water. In order to sort foamed products having a lower density, a method of flotation with alcohol having a low specific gravity is effective.

In the flotation step, in the above-described production method of the present invention, the heat-foamed fine hollow glass spheres are dispersed in water, and particles having a density greater than 1.0 g / cm ³ are separated and removed by centrifugal force. Is very effective for obtaining a product having an average particle density of less than 0.7 g / cm ³ and can improve the production capacity. This is because the smaller the diameter, the more difficult it is to remove the pierced hollow body simply by mixing it with water and allowing it to stand. That is, it is considered that the crushed pieces of the hollow body can be settled and separated as long as they are dispersed in water. However, in the case of a pierced hollow body, the smaller the diameter becomes, the more difficult it is for water to enter the inside and the more difficult it is to separate.

Further, the formed hollow body is preliminarily degassed under reduced pressure and then dispersed in water, or is dispersed in water and degassed under reduced pressure, and then has a density of 1.0 g / cm ³ by centrifugal force.
Separating and removing larger particles, for similar reasons,
The defective hollow body that has been completely broken can be removed, and the weight of the product can be reduced.

According to the present invention, a fine hollow aluminosilicate glass sphere having a fine particle diameter, a high sphericity, a high strength, and a high heat resistance can be obtained. Due to the manufacturing method of building up the silicate glass raw material and the spraying of the slurry, the size of the droplets is easy to be uniform, and one droplet forms one glass sphere, which foams and becomes a hollow body This is considered to be for forming one minute hollow glass sphere. It is considered that the reason why the molten particles are generated substantially in units of droplets is that the coalescence of the droplets is prevented by the combustion gas generated when the slurry that has become the droplets burns.

In addition, the centrifugal force is applied during the separation and collection of the lightly floated water floating product, and the density of the hollow product can be significantly reduced by applying the centrifugal force after degassing. This is because water can penetrate into the small-diameter puncture particles. Also, formation of a silica layer on the surface by perhydropolysilazane or the like can effectively prevent sodium from being eluted.

[0062]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

[Example 1] 1.0 kg of secondary sedimentary shirasu produced in Yoshida-cho, Kagoshima Prefecture as kerosene as volcanic glassy sediment.
The slurry was prepared by adding 100 g of homogenol L1820, which is an anionic surfactant of Kao Corporation. This slurry was wet-pulverized with a medium stirring mill to obtain a raw material slurry.

The medium stirring type mill used had an internal volume of 140.
0 cc, and the material used was zirconia.
The beads were made of zirconia having an average diameter of 0.65 mmφ and used in an amount of 1120 cc. The operating condition is 25 rpm.
It was set to 00 rpm and wet-pulverized for 30 minutes. The finely pulverized shirasu was recovered from the obtained raw material slurry and observed by SEM. As a result, the average particle diameter was 0.5 μm.

The obtained raw material slurry was sprayed by a two-fluid nozzle, ignited by a pilot burner, and sprayed and burned.
A hollow glass sphere was produced. The hollow glass spheres were collected with a bag filter, mixed with water, and centrifuged to determine the water levitation rate of the water-floating product. As a result, it was confirmed that about 20% by mass of the hollow glass spheres floated on the water surface.

After collecting the hollow glass spheres floating on the water surface, the average particle diameter was measured with a laser scattering type particle size measuring apparatus. The average particle diameter was 15.0 μm. The true density was measured with a dry automatic densitometer.
It was 68 g / cm ³ . In the confirmation of the particle shape by SEM observation, substantially all of the particles are in the range of 1 ≦ (length in the long axis direction / length in the short axis direction) <1.2, and no broken pieces of the hollow body are observed. The pierced hollow body was hardly observed.

Further, at the time of separating the water-floating product, the target powder was reduced to 0.01 MPa at 20 ° C. in a container, and water was added while maintaining the reduced pressure to form a 5% by mass slurry. When the water levitation rate was measured by centrifugation, it was confirmed that about 85% by mass floated on the water surface.
After collecting the hollow glass spheres floating on the water surface in the same manner as described above, the average particle diameter was measured with a laser scattering type particle size measuring apparatus, and the average particle diameter was 16.3 μm.

When the true density was measured by a dry automatic densitometer, it was 0.62 g / cm ³ . In the confirmation of the particle shape by SEM observation, substantially all particles were 1 ≦
(Long axis direction / short axis direction) <1.2
No broken piece of the hollow body and no pierced hollow body were observed.

When the strength of 10% by volume collapse of this sample was measured with a pressure resistance test apparatus, 8.5% by volume was broken at 100 MPa which is the pressure application limit.
The strength of 0 volume% disintegration was 100 MPa or more. Further, the value in the strength equation is 770 MPa when calculated using the Young's modulus of 86 GPa of the aluminosilicate glass, and the actual strength of 10% by volume collapse is 10% or more of the collapse strength calculated from the strength equation. Was.

The obtained aluminosilicate glass hollow body
Has a chemical analysis value in mass% of SiO _Two: 73.5%, A
l_TwoO_Three: 14.1%, Na_TwoO: 4.3%, K_TwoO: 4.
1%: CaO: 2.0%, Fe_TwoO_Three: 2.0%, B
_TwoO_Three: 0.0%. Also, aluminosilicate gas
The hollow hollow body was kept at 600 ° C. for 1 hour in a platinum crucible.
Later, when the average particle size and true density were measured,
Did not.

[Example 2] 1.0 kg of secondary sedimentary shirasu and 35.5 g of Na ₂ SO ₄ produced in Yoshida-cho, Kagoshima Prefecture were supplied with 4.0 kerosene.
The resulting mixture was wet-milled in the same manner as in Example 1 except that the slurry was prepared by adding 100 g of the above-mentioned homogenol L1820 to obtain a raw material slurry. When a mixed powder of shirasu and Na ₂ SO ₄ was recovered from the obtained raw material slurry and observed by SEM, the average particle diameter was 0.7 μm.

The obtained raw material slurry was sprayed by a two-fluid nozzle, ignited by a pilot burner, and sprayed and burned.
A hollow glass sphere was produced. The hollow glass spheres were collected by a bag filter, mixed with water, and centrifuged to determine the water levitation rate by centrifuging the water-float product. As a result, it was confirmed that about 30% by mass of the hollow glass spheres floated on the water surface.

After collecting the hollow glass spheres floating on the water surface, the average particle diameter was measured with a laser scattering type particle size measuring apparatus. The average particle diameter was 11.5 μm. The true density was measured with a dry automatic densitometer.
It was 63 g / cm ³ . In the confirmation of the particle shape by SEM observation, substantially all particles were 1 ≦ (length in the long axis direction /
(Length in the short axis direction) <1.2, no broken pieces of the hollow body were observed, and almost no pierced hollow body was observed.

Further, when separating the water-floating product, the target powder is depressurized in a vessel at 20 ° C. to 0.01 MPa, water is added while maintaining the depressurization to form a slurry, and then centrifuged again. As a result, it was confirmed that about 90% by mass floated on the water surface.

After collecting the hollow glass spheres floating on the water surface in the same manner as in Example 1, the average particle diameter was measured with a laser scattering type particle size measuring apparatus. The average particle diameter was 13.2 μm. The true density was measured by a dry automatic densitometer to find that it was 0.59 g / cm ³ . In the confirmation of the particle shape by SEM observation, substantially all of the particles are in the range of 1 ≦ (longitudinal length / short axis length) <1.2, and the broken piece of the hollow body and the pierced hollow body Was not observed at all.

Then, 100 g of the obtained micro hollow glass spheres was taken out, and a perhydropolysilazane solution diluted to 20% with xylene was sprayed onto the micro hollow glass while spraying with a 5 liter internal volume pot mixer. 60 g was sprayed evenly on the sphere. This was dried in hot air at 200 ° C. by a flash dryer. Next, the dried fine hollow glass spheres were sprinkled thinly on a porcelain container and fired at 450 ° C. for 1 hour in a small electric furnace.

5 g of the surface-treated product was immersed in 500 g of pure water at 100 ° C. for 24 hours using a fluororesin container, and the amount of sodium eluted was measured by the atomic absorption method.
The elution amount was 1.1 mg. On the other hand, as a comparison, the same operation was performed without performing the surface treatment, and the amount of sodium eluted was measured. As a result, the amount of elution was 58 mg, demonstrating the sodium elution suppression effect of perhydropolysilazane.

Aluminosilicate glass hollow body obtained
Has a chemical analysis value in mass% of SiO _Two: 72.5%, A
l_TwoO_Three: 13.9%, Na_TwoO: 5.6%, K_TwoO: 4.
1%, CaO: 2.0%, Fe_TwoO_Three1.9%, B
_TwoO_Three: 0.0%. Also, aluminosilicate gas
The hollow hollow body was kept at 600 ° C. for 1 hour in a platinum crucible.
Later, when the average particle size and true density were measured,
Did not.

[Example 3] 1.0 kg of secondary sedimentary shirasu and 33.5 g of Li ₂ CO ₃ produced in Yoshida-cho, Kagoshima Prefecture were supplied with 4.0 kerosene.
The resulting mixture was wet-milled in the same manner as in Example 1 except that the slurry was prepared by adding 100 g of the above-mentioned homogenol L1820 to obtain a raw material slurry. A mixed powder of shirasu and Li ₂ CO ₃ was recovered from the obtained raw material slurry and observed by SEM. As a result, the average particle diameter was 0.6 μm.

The obtained raw material slurry was sprayed by a two-fluid nozzle, ignited by a pilot burner, and sprayed and burned.
A hollow glass sphere was produced. The hollow glass spheres were collected with a bag filter, mixed with water, and centrifuged to determine the water floating rate by centrifuging the water floating product. As a result, it was confirmed that about 35% by mass floated on the water surface.

After collecting the hollow glass spheres floating on the water surface, the average particle diameter was measured with a laser scattering type particle size analyzer to find that the average particle diameter was 15.3 μm. The true density was measured with a dry automatic densitometer.
It was 51 g / cm ³ . In the confirmation of the particle shape by SEM observation, substantially all particles were 1 ≦ (length in the long axis direction /
(Length in the short axis direction) <1.2, no broken pieces of the hollow body were observed, and almost no pierced hollow body was observed.

Further, when separating the water-floating product, the target powder is reduced in pressure to 0.01 MPa at 20 ° C. in a vessel, and water is added while maintaining the reduced pressure to form a slurry, and then centrifuged again. As a result, it was confirmed that about 95% by mass floated on the water surface. After collecting the hollow glass spheres floating on the water surface in the same manner as described above, the average particle diameter was measured with a laser scattering type particle size analyzer, and the average particle diameter was 17.0 μm. When the true density was measured by a dry automatic densitometer, it was 0.49 g / c.
m ³ .

In the confirmation of the particle shape by SEM observation, substantially all particles were 1 ≦ (length in the long axis direction / length in the short axis direction)
Within the range of <1.2, neither a broken piece of the hollow body nor a punctured hollow body was observed. When the strength of 10% by volume collapse was measured for this sample, it was 50 MPa. Further, the value in the strength equation is 3 when calculated in the same manner as in Example 1.
30 MPa, and the actual strength of 10% by volume collapse was 15% or more of the collapse strength calculated from the strength formula.

Aluminosilicate glass hollow body obtained
Has a chemical analysis value in mass% of SiO _Two: 72.5%, A
l_TwoO_Three: 13.9%, Na_TwoO: 4.3%, K_TwoO: 4.
1%, Li_TwoO: 1.3%, CaO: 2.0%, Fe_TwoO
_Three1.9%, B_TwoO_Three: 0.0%. Also, Al
Minosilicate glass hollow body in a platinum crucible at 600 ° C
And then measure the average particle size and true density
It didn't change.

Example 4 (Comparative Example) A secondary sediment produced in Yoshida-cho, Kagoshima Prefecture was dry-dried to an average particle diameter of 12 μm using an ACM pulperizer, which is an impact-type pulverizer equipped with a classification function of Hosokawa Micron Corporation. Crushed. 100 parts by mass of the pulverized powder was added to 0.05 mol / mol of aluminum sulfate.
L to an aqueous solution of 160 parts by mass (ratio of aluminum sulfate to powder: about 3.5 parts by mass), and while stirring at room temperature, a 1 mol / L aqueous solution of ammonium hydrogen carbonate was further added dropwise over 2 hours, and aluminum sulfate was added. The whole amount was added until the amount was equivalent to hydrolysis. End of dripping 2
After a period of time, the coated solid was collected by filtration, washed with water, scattered thinly in a stationary thermostatic dryer set at 105 ° C., and dried for 5 hours.

Next, after drying this powder at 120 ° C.,
Into the flame formed by the LPG gas burner, the mixture was introduced while being stirred with pressurized air to prevent agglomeration. Melting,
After the foamed powder was collected with a bag filter, it was mixed with water, and the water-floating product was allowed to stand and collected.

When the average particle diameter of the recovered powder was measured by a laser scattering type particle size analyzer, the average particle diameter was 16.8 μm. The true density was measured with a dry automatic densitometer to find that it was 0.98 g / cm ³ . In the confirmation of the particle shape by SEM observation, more than half of the particles had a major axis length / minor axis direction length of 1.2 or more, and more than half of the particles were not single foamed spheres but aggregated multiple large and small foamed spheres Met.

Next, after deaeration under reduced pressure as in Example 1, water was mixed to form a slurry, followed by centrifugation. When the average particle diameter was measured with a laser scattering particle size analyzer, the average particle diameter was 18.2 μm. The true density was measured by a dry automatic densitometer to find that it was 0.85 g / cm ³ . S
In the confirmation of the particle shape by EM observation, the major axis length / minor axis direction length of half or more of the particles was 1.2 or more, and more than half of the particles were not single foamed spheres but a plurality of large and small foamed spheres aggregated. It was a shape.

Example 5 (Comparative Example) Silicon Dioxide 490
g, sodium carbonate 90 g, calcium carbide 123 g,
Boric acid 187g, zinc oxide 8g, aluminum oxide 4
g, dicalcium phosphate 29 g, lithium carbonate 19
g, potassium carbonate 11 g and sodium sulfate 9 g in kerosene 4
After mixing in 2,000 g, the above-mentioned homogenol L
100g of 1820 was added, and the mixture was wet-pulverized using a medium stirring mill in the same manner as in Example 1 to obtain a slurry of a glass-mixed raw material. When the glass-mixed raw material was recovered from the obtained glass-mixed raw material slurry and observed by SEM, the average particle size was 0.5 μm.

The obtained slurry of the glass-mixed raw material was sprayed by a two-fluid nozzle, ignited by a pilot burner, and spray-burned to produce a hollow glass spherical body. The hollow glass spheres were collected with a bag filter, mixed with water, and centrifuged to determine the water levitation rate by centrifuging the water-floated product. As a result, it was confirmed that 40% by mass floated on the water surface.

After collecting the hollow glass spheres floating on the water surface, the average particle diameter was measured with a laser scattering type particle size measuring device and found to be 15 μm. 1 ≦ (length in the long axis direction / length in the short axis direction) <1.2. The true density of the water-floating product measured by a dry automatic densitometer is 0.54 g.
/ Cm ³ .

The obtained hollow glass sphere had a chemical analysis value of 64.2% by mass of SiO _{2 and} 0.1% by mass of Al ₂ O ₃ : by mass%.
5%, Na ₂ O: 5.3%, K ₂ O: 0.8%, Li
₂ O: 0.8%, CaO: 15.7%, B ₂ O ₃ : 11.
7%, ZnO: 1.0%.

After holding the hollow glass spheres in a platinum crucible at 600 ° C. for 1 hour, the average particle size and true density were measured. The average particle size was 29 μm and the true density was 0.91 g / cm ³ . It was confirmed that the heat resistance was poor, that the particles were fused together, and that the hollow portion was partially collapsed.

Example 6 0.75 kg of 4A zeolite and 20.3 g of Na ₂ SO ₄ were mixed with 1.34 kg of kerosene, and 77.0 g of an anionic surfactant homogenol L-1820 manufactured by Kao Corporation was added. And a slurry was prepared.
This slurry was wet-pulverized with a medium stirring mill under the same conditions as in Example 1 except that the wet pulverization time was 2 hours, to obtain a raw material slurry. 4 from the obtained raw material slurry
The mixed powder of zeolite A and Na ₂ SO ₄ was recovered and SE
M observation revealed an average particle size of 1.1 μm.

The obtained raw material slurry was sprayed by a two-fluid nozzle, ignited by a pilot burner, and sprayed and burned.
A hollow glass sphere was produced. The hollow glass spheres were dry collected using a bag filter.

The average particle size of the hollow glass spheres collected by the dry method was measured with a laser scattering type particle size measuring device. The average particle size was 12.6 μm. When the true density was measured by a dry automatic densitometer, it was found to be 0.73 g / c
m ³ . In confirmation of particle shape by SEM observation,
Substantially all of the particles are in the range of 1 ≦ (length in the long axis direction / length in the short axis direction) <1.2, no broken pieces of the hollow body are observed, and almost all the pierced hollow bodies are observed. Was not done.

When the strength of 10% by volume collapse of this sample was measured by a pressure tester, 3.2% by volume was broken at the pressure application limit of 100 MPa, and the strength of 10% by volume collapse was substantially 100 MPa. That was all. Also, the value in the strength equation is 9 when calculated in the same manner as in Example 1.
It was 90 MPa, and the actual strength of 10% by volume collapse was 10% or more of the collapse strength calculated from the strength formula.

Then, 100 g of the dry-collected hollow glass spheres were collected, and while stirring with a pot-type mixer having an internal volume of 5 liters, a perhydropolysilazane solution diluted to 20% with xylene was sprayed onto the fine hollow glass spheres. 60 g was sprayed evenly on the sphere. This was dried in hot air at 200 ° C. by a flash dryer. Next, the dried fine hollow glass spheres were sprinkled thinly on a porcelain container and fired at 450 ° C. for 1 hour in a small electric furnace.

5 g of the surface-treated product was added to 500 g of 100 ° C.
Immerse in pure water for 24 hours using a fluororesin container,
When the elution amount of lium was measured by the atomic absorption method,
The elution amount was 3.6 mg. On the other hand, for comparison,
Perform the same operation without surface treatment to dissolve sodium.
When the output was measured, the elution amount was 235 mg.
-Hydropolysilazane inhibits sodium dissolution
Has been demonstrated. The obtained aluminosilicate glass hollow
The chemical analysis of the body is expressed in mass% _Two: 45.7%,
Al_TwoO_Three: 34.8%, Na_TwoO: 19.5%, B
_TwoO_Three: 0.0%. Also, aluminosilicate gas
The hollow hollow body was kept at 600 ° C. for 1 hour in a platinum crucible.
Later, when the average particle size and true density were measured,
Did not.

[0100]

According to the present invention, a microparticle having a small particle diameter, a high sphericity, a low density and a high strength, and a high heat resistance as compared with a conventional hollow borosilicate glass microsphere. A hollow glass spherical body can be obtained, and these fine hollow aluminosilicate glass hollow bodies can be efficiently and industrially produced even in comparison with a conventional method for producing a minute hollow glass hollow body obtained from a raw material of shirasu.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shoji Tanaka 10 Goi Kaigan, Ichihara City, Chiba Prefecture Asahi Glass Co., Ltd. F-term (reference) 4G062 AA14 BB06 CC01 CC08 DA05 DA06 DA07 DB03 DB04 DB05 DC01 DC02 DD01 DE01 DF01 EA01 EA02 EA03 EA04 EA10 EB01 EB02 EB03 EB04 EC01 EC02 EC03 EC04 ED01 ED02 ED03 ED04 EE01 EE02 EE03 EE04 EF01 EF02 EF03 EF04 EG01 EG02 EG03 EG01 H01 H01 H01 H01 H01 H01 H01 F01 GA01 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM15 NN32 NN33 NN34 4G075 AA27 BB08 BB10 BD15 BD16 CA02 CA03 CA57 CA65 DA13 EA05 FA14 FB06

Claims (7)

[Claims] 1. A volume-based average particle diameter of 1 to 20 μm, an average particle density of 0.20 to 1.50 g / cm ³ , and a sphericity of 1 ≦ (length in major axis / length in minor axis) <1. in the range of .2, SiO ₂ is 30% to 85% composition by mass%, Al ₂ O ₃
But 6-45%, alkali metal oxides is 0-30% alkaline earth metal oxide 0 to 30%, and hollow glass microspheres B ₂ O ₃ is made of 0 to 1%, and 10 volume A minute hollow aluminosilicate glass sphere having a percent collapse strength of 10% or more of the theoretical strength given by the formula: 16.7 × E × (t / 2a) ^2.5 . However,
E is the Young's modulus (unit: GPa) of the glass constituting the hollow micro glass body, and t is the thickness (unit: m) of the shell of the hollow glass body.
m) and a are the radii of the hollow portions of the minute hollow glass spheres (unit:
mm). 2. An average particle density of 0.20 to 0.70 g / c.
2. The micro hollow aluminosilicate glass sphere according to claim 1, wherein m ³ is m ³ . 3. The method according to claim 1, wherein a silica film is formed on the surface.
Or a micro hollow aluminosilicate glass sphere according to 2 above. 4. A raw material slurry having an average particle diameter of 2 μm or less is prepared by wet-grinding a glass blended raw material, and the slurry is converted into droplets containing the blended raw material, and the droplets are heated to vitrify the mixture. And the volume-based average particle diameter is 1
-20 μm, average particle density 0.20-1.50 g / c
m ³ , sphericity is 1 ≦ (length in the major axis direction / length in the minor axis direction) <1.
A second range, the SiO ₂ composition in wt% 30 to 85
%, Al ₂ O ₃ is 6 to 45%, and alkali metal oxide is 0 to 0%.
30%, alkaline earth metal oxide 0 to 30% B ₂ O ₃
Is a minute hollow glass sphere consisting of 0 to 1%, and the strength of 10% by volume collapse is expressed by the formula: 16.7 × E × (t / 2a)
^A process for the production of micro hollow aluminosilicate glass spheres that are at least 10% of the theoretical strength given by ^2.5 . Here, E is the Young's modulus (unit: GPa) of the glass constituting the minute glass hollow body, t is the thickness (unit: mm) of the shell of the glass hollow body, and a is the hollow radius (unit) of the minute hollow glass spherical body. : Mm). 5. A method of heating a glass-mixed raw material,
The method for producing a fine hollow aluminosilicate glass sphere according to claim 4, wherein an inorganic substance that generates steam, carbon dioxide, sulfur oxide or nitrogen oxide gas is added. 6. The fine hollow aluminosilicate glass sphere according to claim 4, wherein the formed fine hollow glass sphere is dispersed in water, and particles having a density of more than 1.0 g / cm ³ are separated and removed by centrifugal force. How to make the body. 7. The resulting fine hollow glass spheres are degassed under reduced pressure and then dispersed in water, or dispersed in water and degassed under reduced pressure, and then the particles having a density greater than 1.0 g / cm ³ by centrifugal force. The method for producing a fine hollow aluminosilicate glass spheroid according to claim 6, wherein spheres are separated and removed.