JPH09278484A - Phosphate glass spherical solid body and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phosphate glass spherical solid body vitrified at a low temp., excellent in water resistance and easy to produce by adopting a specific glass composition. SOLUTION: The phosphate glass spherical solid body consists substantially of, by mol.%, 5-35% Li2 O+Na2 O+K2 , 35-55% ZnO+MgO, 20-35% P2 O5 , 1-5% Al2 O3 and 8-20% B2 O3 and has 0.1-50μm average particle diameter. To produce the glass spherical solid body, an aq. solution or a slurry of a prepared raw material prepared so as to secure the composition above is prepared. The aq. solution or the slurry is made into liquid drops and the liquid drops are fused by heating to be vitrified and made spherical.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a phosphate-based glass spherical solid body and a method for producing the same.

[0002]

2. Description of the Related Art As a spherical glass solid substance, SiO ₂ +
_{P 2 O 5: 0~20, B} 2 O 3: 5~45, TiO 2:
1-20, BaO + CaO + MgO + SrO: 25-6
0, Al ₂ O ₃ + ZrO ₂ : 0 to 15, Cr ₂ O ₃ + M
It is known that the composition is nO ₂ + Fe ₂ O ₃ + CoO + CdO: 1 to 8 (each weight%) (Japanese Patent Publication No. 45-125).
04). However, since this spherical solid has a small content of P ₂ O ₅ and does not contain an alkali metal oxide, it has a drawback that the melting temperature during vitrification becomes high.

On the other hand, methods for producing spherical solid bodies are generally classified into the following methods. A method (method 1) of obtaining a spherical body of a target substance by heat treating or the like to make the shape spherical with a precursor. A method of obtaining a spherical substance by the sol-gel method (method 2). A method of directly spraying the melt to fix the shape as spherical particles (method 3). A method in which particles of the same material as the target spherical body are melted in a high-temperature flame to form a spherical shape by surface tension (method 4).

In the method 1, the spherical solid of carbon resin is manufactured by heat-treating the precursor spherical solid of phenol resin, but it is not efficient because it is necessary to manufacture the spherical solid of precursor.

In Method 2, some of the spherical silica solids are produced by the sol-gel method by hydrolyzing alkoxide under alkali, but the raw material cost is high and the production process is not inexpensive.

In Method 3, the melt is rich in fluidity, such as titanium-barium glass, and is limited to glass having low viscosity and high surface tension.

In Method 4, a large number of glass spherical solid bodies are produced, and a block of glass or crystals is crushed and the fine powder is put into a high temperature flame to melt and fluidize, and the surface tension is utilized. When it becomes spherical, it is cooled rapidly to fix the shape.

In Method 4, the dried glass fine powder is dispersed in hot air at high temperature, so that the glass powder easily aggregates as it becomes smaller, and some particles are fused when the glass is melted. It was difficult to obtain a glass spherical solid body having a uniform particle size distribution. Further, since a dry pulverization operation or the like is used in the step of obtaining the glass powder, dust is generated, environmental pollution is caused, and it takes a long time to pulverize, resulting in an inefficient process.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, vitrifies at a low temperature, has excellent water resistance, and is easy to manufacture. The purpose is to provide a method.

[0010]

According to the present invention, in terms of mol%, Li ₂ O + Na ₂ O + K ₂ O 5 to 35%, ZnO + MgO 35 to 55%, P ₂ O ₅ 20 to 35%, Al ₂ O ₃ 1 to 5%, B ₂ O _{3 8 to} 20%, and a phosphate glass sphere having an average particle diameter of 0.1 to 50 μm, and a compounding raw material prepared to have the above composition Is prepared, and the aqueous solution or slurry is made into droplets, and the droplets are heated and melted to vitrify and spheroidize.

In the phosphate glass spherical solid body of the present invention, the content of Li ₂ O, Na ₂ O and K ₂ O is 5 in total.
˜35 mol%. If the total content is less than 5 mol%, the glass transition point becomes high, and microspheres cannot be easily obtained. If the total content exceeds 35 mol%, the water resistance of the glass decreases. Li ₂ O, Na ₂ O and K ₂ O may be used alone or in combination of two or more.

The total content of ZnO and MgO is 35 to 5
It is set to 5 mol%. If the total content is less than 35 mol%, the water resistance of the glass is insufficient, and if the total content exceeds 55 mol%, the glass transition point increases or the devitrification of the glass increases. ZnO and MgO may be used alone or in combination of two kinds.

If the content of P ₂ O ₅ is less than 20 mol%, vitrification tends to be difficult, and if it exceeds 35 mol%, the water resistance decreases.

When the content of Al ₂ O ₃ is less than 1 mol%, the water resistance is lowered, and when it exceeds 5 mol%, it is difficult to melt and a homogeneous glass cannot be obtained.

When the content of B ₂ O ₃ is less than 8 mol%, the viscosity of the glass is drastically lowered with respect to the temperature rise and it is difficult to form the glass into a desired shape. Sex is also reduced.

Of these ranges, in terms of mol%, substantially Li ₂ O + Na ₂ O + K ₂ O 7 to 25%, ZnO + MgO 42 to 48%, P ₂ O ₅ 25 to 30%, Al ₂ O ₃ 1 to _{3%, B 2 O 3 9~15} %, phosphate-based glass microspheres solid body made of the mechanical strength,
It is particularly preferable because it has excellent water resistance and is easy to manufacture.

The composition of the phosphate glass spherical solid body may be such that the total amount of the above components is 95 mol% or more, and the balance 5
If it is less than mol%, a coloring agent such as Fe ₂ O ₃ or CoO,
Other property improving agents may be contained.

If the average particle size of the spherical solid glass of phosphate type is less than 0.1 μm, the production becomes difficult, and if it exceeds 50 μm, the surface properties are deteriorated when it is used as a filler for a resin, and practical use occurs. Not relevant. The average particle size is a particle size corresponding to 50% by weight of the cumulative distribution curve of particles,
The integrated weight of particles having a diameter of at least this size is equal to the integrated weight of particles having a diameter of at least this size.

Since the phosphate-based glass spherical solid glass has a small change in viscosity with respect to temperature changes, it is easy to manufacture the spherical solid. This phosphate glass spherical solid has a low melting point due to its glass composition, can impart flame retardancy when filled in a resin, and is spherical, so isotropic compared to conventional fillers. It is suitable for use as a filler used in precision instruments because it has less characteristics and warps and deformation when filled with resin.

In order to manufacture the phosphate glass spherical solid body, first, an aqueous solution and a slurry of prepared raw materials prepared so as to have the above composition are prepared.

Of the prepared raw materials, Li ₂ O, Na ₂ O and K ₂
As the raw material for the O component, hydroxides, sulfates, nitrates, chlorides, phosphates and the like can be used as well as carbonates such as lithium carbonate, sodium carbonate and potassium carbonate.

The raw materials for the ZnO and MgO components include oxides such as zinc oxide and magnesium oxide, phosphates such as zinc phosphate, hydroxides such as magnesium hydroxide, and sulfates such as zinc sulfate. A nitrate such as zinc nitrate can be used.

As the raw material of the P ₂ O ₅ component, in addition to orthophosphoric acid and ammonium phosphate, it may be used in the form of a compound with an alkali component, zinc and an aluminum component.

As the raw material for the B ₂ O ₃ component, boric anhydride, orthoboric acid, sodium tetraborate decahydrate or the like can be used.

The compounding raw material is used by dissolving it in water. Also,
When it does not dissolve in water, it can be mixed with a liquid containing a flammable liquid and used as a slurry.

If the average particle size of the raw material to be used as a slurry exceeds 3 μm, it becomes difficult to obtain a spherical solid substance having a uniform composition. Therefore, if the average particle size is large, it is preferable to grind the average particle size to 3 μm or less. Further, if the average particle size of the raw material mixture is 1 μm or less, it is more preferable in that the glass composition is further homogenized. When the raw materials having a large particle size are contained in the raw material for blending, the raw materials may be classified in a wet state, and those having a predetermined particle size may be selected and used.

As the pulverization method, wet pulverization is particularly preferable because it is easily made into fine particles and the uniformity of the glass composition is increased by mixing. The liquid used for the wet pulverization is not particularly limited, but it is preferable to use the same liquid as the liquid in the form of liquid droplets because the working process is simplified. Further, it is particularly preferable to use a liquid containing a flammable liquid in consideration of heating by spray combustion afterwards. As the flammable liquid, particularly kerosene, heavy oil, alcohols, etc. are easy to handle, inexpensive and easy to burn, and the prepared raw materials are efficiently and uniformly heated, and thus are suitable as a liquid constituting the slurry of the present invention. is there.

If the amount of the liquid is adjusted so that the concentration of the glass preparation raw material in the liquid in the wet pulverization step is the same as the concentration of the glass preparation raw material in the slurry in the form of droplets, the working process is simplified. It is preferable because it is converted into

The wet pulverizer used is more preferably a medium stirring type mill represented by a ball mill or a bead mill,
Other wet crushers may be used. In order to reduce contamination from the material of the crusher, alumina,
It is preferable to select zirconia or a composite ceramic of alumina and zirconia.

When the slurry of the compounding raw material does not have the predetermined concentration, the liquid of the shortage is added to dilute it or it is concentrated to adjust the slurry of the compounding raw material to the predetermined concentration. If the concentration of the solid content in the slurry is too low, productivity and economic efficiency will decrease, and if it is too high, the viscosity will increase, making it difficult to form droplets with a small diameter and solid particles with a uniform particle size distribution. Hard to get. The concentration of the prepared raw material in the slurry is 5 to
A range of 50% by weight, particularly 10 to 40% by weight is preferable.

By heating the aqueous solution or slurry of the compounding raw material thus obtained in the form of droplets, the compounding raw material contained in one droplet is melted and vitrified to be formed into a spherical solid substance of approximately one particle. .

When the compounding raw material contains a foaming agent and when the compounding raw material is vitrified by heating to generate a gas and the molten glass becomes a hollow body, the heating temperature is adjusted to adjust it. Can be a solid body. For example, a spherical solid body can be manufactured by heating the compounding raw material to a temperature equal to or higher than the foaming end temperature to vitrify.

Further, the aqueous solution or slurry of the prepared raw material can be used by emulsifying it in a liquid containing a flammable liquid which is heated by being burned later. In this case, the compounding raw material contained in one emulsion particle in the droplet is melted and formed into one spherical body, so that a solid substance having a smaller diameter can be obtained.

The droplet forming means is not particularly limited, but a spraying method is preferable. As a spraying method, a spray atomizer such as a liquid column type or liquid film type two-fluid nozzle or an ultrasonic atomizer can be used, and the two-fluid nozzle is preferable in terms of easy mass production. When using the two-fluid nozzle, air, a flammable gas, or a combustion-supporting gas can be used as the atomizing gas.

The heating temperature depends on the melting temperature and the residence time of the phosphate glass raw material. In particular,
It is in the range of 300 to 1500 ° C.

The formed phosphate glass spheres are recovered by a known method such as a bag filter or a wet packed bed recovery method.

[0037]

According to the present invention, a phosphate type glass spherical solid substance having a small diameter and a uniform particle diameter can be obtained. This is to heat the aqueous solution, slurry or emulsion of the phosphate-based glass compounding raw material into fine droplets having a uniform particle size to heat the compounding raw material contained in one droplet or emulsion particle. , It is thought that it becomes a phosphate glass spherical solid by melting.

[0038]

【Example】

[Example 1] An example of preparing an aqueous solution of a raw material for preparation and heating the aqueous solution to produce a phosphate glass spherical solid body will be described.

Deionized water 180.0 g, 75% orthophosphoric acid 79.8 g, aluminum hydroxide 3.3 g, zinc sulfate heptahydrate 87.8 g, magnesium hydroxide 11.9.
g, lithium hydroxide monohydrate 5.1 g, sodium hydroxide 0.8 g, potassium hydroxide 8.0 g, sodium borate decahydrate 30.0 g were dissolved with stirring at a temperature of 60 ° C. Was prepared. The aqueous solution was sprayed into a tubular furnace set at 1500 ° C. using a two-fluid nozzle and heated to produce a spherical body.

The spherical body was collected by a bag filter and the following measurements were carried out. The average particle size measured by the light scattering method (using a Shimadzu laser diffraction particle size analyzer) is 10μ.
m was a result of observation with a scanning electron microscope, and each was a spherical body, and as a result of measurement of specific gravity by an air-comparison hydrometer, all were solid. Furthermore, as a result of X-ray diffraction measurement, it was confirmed that the glass was all glass.

The composition of this glass is Li ₂ O: 4.6,
Na ₂ O: 5.2, K ₂ O: 5.0, ZnO: 27.
0, MgO: 17.7, P ₂ O ₅ : 29.5, Al ₂ O
_{3: 2.0, B 2 O 3} : was 9.0 (the mol%).

[Example 2] An example of preparing a slurry of a compounding raw material and heating the slurry to produce a phosphate glass spherical solid body is shown.

Phosphorous acid 66.8 g, aluminum hydroxide 4.4 g, zinc sulfate heptahydrate 117.1 g, magnesium hydroxide 15.9 g, lithium hydroxide monohydrate 6.8 g, sodium hydroxide 1.1 g, 10.1 g of potassium hydroxide,
40.0 g of sodium borate decahydrate was mixed in 600 g of kerosene, and then wet-milled using a bead mill to obtain a slurry of a phosphate glass compounding raw material.

The bead mill used has an internal volume of 1400 m.
and the material used was zirconia. The beads are made of zirconia with an average diameter of 0.65 mmφ 11
20 ml was put and used. The operating condition is 2500 rpm
The speed was adjusted to rpm and the powder was crushed for 40 minutes. When the solid content was recovered from the obtained slurry of the prepared raw material and observed with a scanning electron microscope, the average particle diameter was 0.5 μm.

The slurry was sprayed with a two-fluid nozzle in the same manner as in Example 1, and ignited by approaching a flame to carry out spray combustion to produce spherical bodies. The combustion temperature at this time is 1100
° C. The spherical body was collected by a bag filter, and the same measurement as in Example 1 was performed. As a result, the average particle diameter of the spherical body was 12 μm, and both of the observation by the scanning electron microscope and the measurement of the specific gravity were spherical solid bodies. Further, as a result of X-ray diffraction measurement, it was confirmed to be glass.

The composition of this glass is Li ₂ O: 4.8,
Na ₂ O: 7.0, K ₂ O: 5.5, ZnO: 25.
5, MgO: 17.4, P ₂ O ₅ : 27.1, Al ₂ O
_{3: 1.7, B 2 O 3} : was 11.0 (each mole%).

Example 3 An example in which an aqueous solution of a raw material for preparation is prepared, the aqueous solution is emulsified in a flammable liquid, and the emulsion is heated to produce a phosphate glass spherical solid is shown.

A preparation raw material aqueous solution similar to that of Example 1 was prepared.
The aqueous solution was added to 400 g of kerosene and the nonionic surfactant 20.
0 g was added to the mixed solution and emulsified with a homomixer to prepare an emulsion.

A spherical body was produced by spraying this emulsion into a tubular furnace set at 1300 ° C. using a two-fluid nozzle, and then igniting by bringing a flame closer thereto to perform spray combustion. The spherical body was collected with a bag filter, and example 1
The same measurement was performed. As a result, the average particle diameter of the spherical body was 12 μm, and both of the observation by the scanning electron microscope and the measurement of the specific gravity were spherical solid bodies. Also, X
As a result of the line diffraction measurement, it was confirmed to be glass.

The composition of this glass is Li ₂ O: 4.8,
Na ₂ O: 6.3, K ₂ O: 5.3, ZnO: 25.
9, MgO: 17.7, P ₂ O ₅ : 28.2, Al ₂ O
_{3: 1.9, B 2 O 3} : was 9.9 (the mol%).

[0051]

The phosphate glass spherical solid body of the present invention is excellent in water resistance and vitrifies at a relatively low temperature, so that it is easy to manufacture. According to the manufacturing method of the present invention, a phosphate-based glass spherical solid body having a uniform particle size and an average particle size of 50 μm or less is easily manufactured industrially.

Claims (3)

[Claims] 1. In terms of mol%, substantially Li ₂ O + Na ₂ O + K ₂ O 5 to 35%, ZnO + MgO 35 to 55%, P ₂ O ₅ 20 to 35%, Al ₂ O ₃ 1 to 5%, B ₂ O _{3 8 to} 20%, a phosphate glass spherical solid substance having an average particle diameter of 0.1 to 50 μm. 2. Li ₂ O + Na ₂ O + K ₂ O 5 to 35%, ZnO + MgO 35 to 55%, P ₂ O ₅ 20 to 35%, Al ₂ O ₃ 1 to 5%, B ₂ O ₃ 8-20%, an aqueous solution or slurry of the compounding raw material prepared so as to have a composition of:
A process for producing a phosphate-based glass spherical solid body in which droplets are heated and melted to be vitrified and spherical. 3. The emulsion according to claim 2, wherein the aqueous solution or slurry is emulsified in a liquid containing a flammable liquid to form an emulsion, and the emulsion is formed into droplets, and the droplets are heated and melted to be vitrified and spherical. A method for producing a phosphate glass spherical solid body.