KR20180053310A - METHOD FOR MANUFACTURING GLASS FOUNDATION ASSEMBLY, METHOD FOR MANUFACTURING GLASS GLASS, - Google Patents

Abstract

Thereby making it possible to assemble a glass raw material containing SiO ₂ , P ₂ O ₅ , and Na ₂ O as a glass composition.
A method for producing a glass raw material assembly by assembling a glass raw material composition containing at least silica, a sodium oxide source, a magnesium oxide source and a phosphoric acid source in the presence of water, wherein the glass raw material composition comprises And magnesium hydroxide in an amount of 3.6 to 8.4 mass% based on the solid content.

Description

METHOD FOR MANUFACTURING GLASS FOUNDATION ASSEMBLY, METHOD FOR MANUFACTURING GLASS GLASS,

The present invention relates to a method of manufacturing a glass raw material assembly, a method of manufacturing a molten glass using the glass raw material assembly, and a method of manufacturing a glass article.

In the production of glass, when the raw material powder is scattered when the raw material powder is put into the melting furnace, problems arise such that the homogeneity of the glass composition is lowered and the raw material is wasted, And a method of using it is proposed.

Patent Document 1 describes white glass containing P ₂ O ₅ contributing to whitening and Na ₂ O preferable for carrying out a chemical strengthening treatment by ion exchange in addition to SiO ₂ as a glass composition.

In Patent Document 1, a white glass is produced by melting a raw material powder, and a method of assembling the raw material powder is not known.

Patent Document 2 discloses a method of producing a water-soluble silicate such as sodium metasilicate and sodium disilicate by previously reacting silica and caustic soda (sodium hydroxide) at a high temperature to prepare an assembly using the silicate as a binder . However, a method of assembling a glass raw material containing phosphorous oxide is not described.

International Publication No. 2014/119623 Japanese Patent Publication No. 56-37176

The present invention relates to a process for producing a glass raw material assembly, in which a glass raw material containing at least SiO ₂ , P ₂ O ₅ and Na ₂ O as a glass composition can be preferably assembled, a process for producing a molten glass using the glass raw material assembly And a method for manufacturing a glass article.

The present invention is the following [1] to [11].

[1] A method for producing a glass raw material assembly by assembling a glass raw material composition containing at least silica, a sodium oxide source, a magnesium oxide source and a phosphoric acid source in the presence of water, wherein the glass raw material composition comprises Wherein the composition comprises 3.6 to 8.4 mass% of magnesium hydroxide relative to the total solids content of the composition.

[2] The process for producing a glass raw material assembly according to [1], wherein an aqueous phosphoric acid solution is used as the phosphorus source and the content of phosphoric acid based on the total solid content of the glass raw material composition is 4.7 to 16.9 mass%.

[3] The process for producing a glass raw material assembly according to [1] or [2], wherein the content of magnesium hydroxide is 4.1 to 7.7 mass% with respect to the total solid content of the glass raw material composition.

[4] The production method of a glass raw material assembly according to any one of [1] to [3], wherein sodium carbonate and / or sodium hydroxide is used as the sodium oxide source.

[5] The process for producing a glass raw material assembly according to any one of [1] to [4], wherein the D50 representing the average particle size of the silica is 5 to 350 μm.

[6] The process for producing a glass raw material assembly according to any one of [1] to [5], wherein the D50 representing the average particle size of the glass raw material assembly is 300 μm to 2 mm.

[7] in a molar percentage indication of the composition of oxide-based glass obtained from the glass raw material assembly, the content of the content of SiO ₂ 50 ~ 74%, the content of _{B 2 O 3 0 ~ 8%} , Al 2 O 3 1 to 8%, MgO content of 3 to 18%, CaO content of 0 to 7%, SrO content of 0 to 10%, BaO content of 0 to 12%, ZrO ₂ content of 0 to 5% , The content of Na ₂ O is 5 to 15%, the content of P ₂ O ₅ is 2 to 10%, the content of other components is 9% or less, the content of CaO, SrO and BaO is 1 to 22% A process for producing a glass raw material assembly according to any one of [1] to [6], wherein the total RO of the contents of MgO, CaO, SrO and BaO is 5 to 25% and the CaO / .

[8] A method for producing a molten glass, comprising the steps of: preparing a glass raw material assembly by the method according to any one of [1] to [7]; and heating the obtained glass raw material assembly to obtain a molten glass.

[9] The method for producing a molten glass according to [8], wherein the glass melting step includes a step of putting the assembly on the molten glass liquid surface in the melting furnace.

[10] The method according to [9], wherein the glass melting step comprises the steps of melting the assembly in a gaseous atmosphere to obtain molten glass particles, and collecting the molten glass particles to obtain a molten glass Gt;

[11] A method for producing a glass article using the method for producing a molten glass according to any one of [8] to [10], comprising the glass melting step, a molding step for molding the obtained molten glass, A process for producing a glass article, comprising a step of quenching the glass.

According to the method for producing a glass raw material assembly of the present invention, an assembly preferable for producing glass containing at least SiO ₂ , P ₂ O ₅ , and Na ₂ O as a glass composition is obtained.

According to the method for producing a molten glass of the present invention, a molten glass containing at least SiO ₂ , P ₂ O ₅ , and Na ₂ O as a glass composition can be produced using the above-described assembly.

According to the method for producing a glass article of the present invention, a glass article containing at least SiO ₂ , P ₂ O ₅ , and Na ₂ O as a glass composition can be produced using the above assembly.

1 is a photograph of the assembly obtained in Production Example 2. Fig.
2 is a photograph of the assembly obtained in Production Example 5. Fig.
3 is a photograph of the assembly obtained in Production Example 7. Fig.
4 is a photograph of the assembly obtained in Production Example 8. Fig.
5 is a photograph of the assembly obtained in Production Example 11. Fig.
6 is a photograph of the assembly obtained in Production Example 12. Fig.

Definitions of the following terms apply throughout the present specification and claims.

The components of the glass are represented by oxides such as SiO ₂ , P ₂ O ₅ and Na ₂ O. The content (glass composition) of each component with respect to the whole glass is expressed as a molar percentage based on oxide based on the mass of the glass as 100%.

The " glass raw material " is a raw material which becomes a component of glass, and the " glass raw material composition " is a composition containing a plurality of glass raw materials. Examples of glass raw materials include oxides and complex oxides, and compounds that can be oxides by thermal decomposition. Examples of the compound which can be an oxide by thermal decomposition include hydroxides, carbonates, nitrates, sulfates, halides and the like. In the present specification, the term " assembly " refers to a glass raw material composition.

In the present specification, the composition of the glass raw material composition is expressed as% by mass in terms of solid content. That is, when the solid content of the glass raw material composition is expressed as a percentage by mass with 100% by mass of the solid content, and when the glass raw material composition contains an aqueous solution, the solid content is contained in the aqueous solution. In addition, the solid content includes the number of crystals.

In the present specification, " D50 " of the glass raw material or the glass raw material composition is an average particle diameter indicated by a 50% diameter in the integrated fraction. The D50 of the glass raw material is a 50% diameter in the integral fraction based on volume measured by laser diffraction method. As a method of measuring the particle size by the laser diffraction method, the method described in JIS Z8825-1 (2001) is used.

The " D50 " of the assembly is a median diameter of a cumulative mass of 50% measured using a sieve or the like.

In the present specification, " " representing the numerical range is used to mean that the numerical values described before and after the numerical range are included as a lower limit value and an upper limit value, and unless otherwise specified, " to " .

<Glass raw material composition>

In the present invention, the glass raw material composition is assembled in the presence of water to prepare a glass raw material assembly. That is, the glass raw material composition is a composition containing all the solid components used for the assembly.

The glass raw material composition contains at least silica, a sodium oxide source (hereinafter, simply referred to as a sodium source), a magnesium oxide source (hereinafter, simply referred to as a magnesium source) and a phosphoric acid source.

[Silica]

As the silica, silica, quartz, cristobalite and amorphous silica can be mentioned. These may be used in one kind or two or more kinds in combination. Silica is preferred in that it is easy to obtain good quality raw materials. They are used in powder form.

The content of silica in the total solid content of the glass raw material composition is preferably 30 to 60 mass%, more preferably 35 to 55 mass%, and still more preferably 40 to 50 mass%. When the content of silica is lower than the lower limit of the above range, the assembly is not adhered well to the wall surface of the granulator and is easy to handle. If the content of silica is below the upper limit of the above range, the strength of the assembly tends to be high.

D50 of silica is preferably 5 to 350 mu m. When D50 of silica is 5 탆 or more, it is easy to handle and easy to assemble. When it is 350 μm or less, a homogeneous assembly tends to be easily obtained.

[Sodium source]

The sodium source is a compound that forms Na ₂ O in the manufacturing process of molten glass.

Examples of the sodium source include sodium carbonate (soda ash), sodium hydroxide (caustic soda), sodium sulfate, sodium nitrate, sodium chloride, sodium fluoride and disodium hydrogenphosphate. Disodium hydrogen phosphate is also a phosphorus source. These may be used in one kind or two or more kinds in combination.

Glass containing an alkali metal oxide such as Na ₂ O is preferable for producing chemically tempered glass by an ion exchange treatment. Specifically, the chemical strengthening by ion exchange treatment is a method in which alkali metal ions (typically, Li ions, Na ions) having a small ionic radius on the glass surface are ion-exchanged at a temperature lower than the glass transition point, Is replaced with alkali ion (typically, Na ion or K ion for Li ion and K ion for Na ion) to form a compressive stress layer on the glass surface, thereby increasing the strength of the glass.

It is preferable to use sodium carbonate (soda ash) as the sodium source, because it is easy to assemble and to prevent agglomeration of the assembly. The D50 of sodium carbonate is not limited, but is preferably 50 to 400 占 퐉, more preferably 55 to 120 占 퐉. If the D50 of the sodium carbonate is within the above range, it is easy to assemble and a homogeneous assembly tends to be obtained.

The ratio of sodium carbonate to the total amount of the sodium source is preferably 70 to 100 mass%, more preferably 80 to 100 mass%.

[Magnesium source]

The magnesium source is a compound which forms MgO in the process of producing molten glass.

Examples of the magnesium source include magnesium hydroxide, magnesium oxide, magnesium carbonate, magnesium sulfate, magnesium nitrate, magnesium chloride, magnesium fluoride and magnesium phosphate octahydrate. Magnesium phosphate octahydrate is also a phosphorus source. These may be used in one kind or two or more kinds in combination.

In the present invention, at least magnesium hydroxide is used as the magnesium source. By containing magnesium hydroxide in an amount of 3.6 to 8.4 mass% based on the total solid content of the glass raw material composition, good granulation property can be obtained and an assembly can be produced.

When the magnesium hydroxide content is 3.6% by mass or more, the granulation property is improved, which facilitates the assembly, and it is easy to obtain a high-strength assembly, which is preferable. When the magnesium hydroxide content is 8.4 mass% or less, agglomeration of the assemblies during assembly can be prevented, and particle diameter control of the assembly is facilitated. In addition, it is preferable that the solidification after assembly is not good.

Further, in order to make the particle size of the assembly more uniform, it is more preferable to contain magnesium hydroxide in an amount of 4.1 to 7.7 mass%.

The D50 of the magnesium hydroxide is not limited, but is preferably from 1 to 30 mu m, more preferably from 2 to 10 mu m. When the D50 of the magnesium hydroxide is within the above range, it is easy to assemble and a homogeneous assembly tends to be obtained.

As the magnesium source, it is also preferable to use magnesium oxide in combination with magnesium hydroxide.

The D50 of the magnesium oxide is not limited, but is preferably 1 to 30 mu m, more preferably 2 to 10 mu m. When the D50 of the magnesium oxide is within the above range, it is easy to assemble and a homogeneous assembly tends to be obtained.

The ratio of magnesium hydroxide to the total amount of the magnesium source is preferably 30 to 95 mass%, more preferably 45 to 90 mass%, in terms of MgO.

[Phosphorus source]

Phosphorus sources are compounds that form P ₂ O ₅ in the process of manufacturing molten glass. The glass containing P ₂ O ₅ is preferable for a method of producing a white glass by forming a fine powder in the interior of the glass. The term "powder phase" means that a single phase glass is divided into two or more glass phases. The diffuse reflection and scattering of light at the interface of the powder phase causes the appearance of the glass to be white. P ₂ O ₅ is a basic component for promoting such powder phase separation.

Examples of the phosphoric acid source include phosphoric acid (H ₃ PO ₄ ), magnesium phosphate octahydrate, aluminum phosphate, disodium hydrogen phosphate and the like.

Particularly, when phosphoric acid (aqueous solution of phosphoric acid) in the form of an aqueous solution is used, the reactivity with the basic substance is good and the assembly speed is increased. In addition, it is preferable to uniformly disperse at the time of assembly so that the phosphorus component in the assembly tends to become homogeneous. Further, the aqueous phosphoric acid solution is inexpensive and economically advantageous.

It is preferable that at least a phosphoric acid (H ₃ PO ₄ ) aqueous solution is contained as the phosphoric acid source. In addition to the aqueous phosphoric acid solution, in addition to the phosphoric acid aqueous solution, one kind of magnesium phosphate octahydrate, aluminum phosphate, disodium hydrogenphosphate and the like may be used as the other phosphoric acid sources, or two or more kinds thereof may be used in combination .

When an aqueous phosphoric acid solution is used, the content of phosphoric acid in the solid content of the raw material for granulation is preferably 4.7 to 16.9 mass%. When the content of phosphoric acid is 4.7 mass% or more, the assembling property is improved, and a high-strength assembly is easily obtained. On the other hand, if the content of phosphoric acid is 16.9 mass% or less, aggregation of the assemblies during assembly can be prevented, and particle diameter control of the assembly is facilitated. In addition, it is preferable that the assemblies after assembly are not hardened due to bonding between the assemblies. Further, if the content of phosphoric acid is 7.5 to 8.4 mass%, the solidification after assembly is remarkably suppressed, which is more preferable.

The ratio of phosphoric acid to the total amount of the phosphorus oxide sources is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, in terms of P ₂ O ₅ .

[Aluminum circle]

An aluminum source may be contained in the glass raw material composition. The aluminum source is a compound that forms Al ₂ O ₃ in the process of producing molten glass.

Examples of the aluminum source include aluminum oxide (alumina), aluminum hydroxide, aluminum phosphate, and feldspar. Aluminum phosphate is also a phosphorus source. These may be used in one kind or two or more kinds in combination.

The D50 of aluminum hydroxide is not particularly limited, but is preferably 2 to 100 占 퐉, more preferably 5 to 60 占 퐉.

The D50 of aluminum oxide is not particularly limited, but is preferably 2 to 100 占 퐉, more preferably 5 to 60 占 퐉.

The D50 of aluminum phosphate is not particularly limited, but is preferably 20 to 300 占 퐉, more preferably 30 to 200 占 퐉.

With respect to the total amount of the aluminum source, the proportion of aluminum hydroxide is preferably 60 to 100% by mass, more preferably 70 to 100% by mass in terms of Al ₂ O ₃ .

[Alkaline earth metal source other than magnesium]

The glass raw material composition may contain an alkaline earth metal source other than magnesium.

In the present invention, alkaline earth metals other than magnesium refer to Ca, Ba, and Sr. The alkaline earth metal source is a compound that forms CaO, BaO, and SrO in the process of manufacturing molten glass. Examples of the alkaline earth metal source include carbonates, sulfates, nitrates, oxides, hydroxides, chlorides, fluorides and phosphates of the alkaline earth metals. These may be used in one kind or two or more kinds in combination. Phosphates of alkaline earth metals are also phosphorus sources. The alkaline earth metal source is preferably a powder. Sulfates, chlorides, and fluorides of alkaline earth metals may act as refining agents.

Further, composite oxides such as complex carbonate such as dolomite and fired dolomite can also be used.

Examples of the barium oxide source include barium carbonate, barium nitrate, barium sulfate and barium chloride, and in particular, barium carbonate is preferable in view of easy availability of raw materials and environment.

The D50 of barium carbonate is not particularly limited, but is preferably 2 to 30 占 퐉, more preferably 2 to 10 占 퐉.

The ratio of barium carbonate to the total amount of the barium oxide source is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, in terms of BaO.

[Other glass raw materials]

The glass raw material composition may contain, in addition to the compounds exemplified above, other known compounds as a glass raw material within a range that does not impair the effect of the present invention.

As other compounds, for example, boron sources such as boric acid and boron oxide; Zirconium sources such as zirconium oxide, zirconium and zirconium silicate; Sodium sulfate, and a sulfur source of aluminum sulfate. These may be used in one kind or two or more kinds in combination.

In order to obtain a high strength and homogeneous assembly, the content of the other compounds is preferably 20 mass% or less, more preferably 10 mass% or less, in total.

[Composition of glass raw material composition]

The composition of the glass raw material composition is adjusted so as to be almost the same as the composition of the intended glass article in terms of oxides, except for components which are easily volatilized in the glass melting step.

[Glass Composition]

As the composition of the glass obtained from the assembly of the above-mentioned glass raw material composition, the following composition (% is in mol%) is preferable. The following composition is preferable as the composition of the white glass, and particularly preferable as the composition of the white glass for the chemical strengthening treatment.

SiO ₂ is 50 to 74%, B ₂ O ₃ is 0 to 8%, Al ₂ O ₃ is 1 to 8%, MgO is 3 to 18%, CaO is 0 to 7%, SrO is 0 to 10%, BaO 0 to 12% of ZrO ₂ , 0 to 5% of ZrO ₂ , 5 to 15% of Na ₂ O and 2 to 10% of P ₂ O ₅ ,

The total content of CaO, SrO and BaO is 1 to 22%

The total RO of the contents of MgO, CaO, SrO and BaO is 5 to 25%

The CaO / RO CaO / RO ratio is less than 0.7.

The total of the components other than the above is preferably 9% or less, more preferably 6% or less.

SiO ₂ is a basic component for forming a glass mesh structure. When the content of SiO ₂ is 50% or more, good weather resistance, scratch resistance and chemical resistance as glass are easily obtained. , Preferably at least 53%, more preferably at least 55%, and even more preferably at least 57%. On the other hand, when the content of SiO ₂ is 74% or less, the melting temperature of the glass is not excessively high and good scratch resistance is easily obtained. , Preferably not more than 70%, more preferably not more than 68%, further preferably not more than 65%.

B ₂ O ₃ is not an indispensable component but contributes to improvement of glass melting property, improvement of whiteness of glass, lowering of thermal expansion rate, and improvement of weather resistance. The content of B ₂ O ₃ is preferably 8% or less, more preferably 7% or less, further preferably 6% or less, more preferably 6% or less, from the viewpoints of suppressing unevenness of whiteness in white glass and improving homogeneity of whiteness. Or less. Here, improvement in whiteness and high degree of whiteness mean that the linear transmittance of glass is low (hereinafter the same).

Al ₂ O ₃ has an effect of improving the chemical durability of the glass and has an effect of remarkably improving the dispersion stability of SiO ₂ and other components and giving a function of making the glass powder uniform, For improvement, it is preferable to contain 1% or more. More preferably 2% or more, still more preferably 2.5% or more, and particularly preferably 3% or more. If the content of Al ₂ O ₃ is excessively large, the melting temperature of the glass becomes excessively high, and the powder does not easily disperse. The content of Al ₂ O ₃ is preferably 8% or less, more preferably 7% or less, further preferably 6% or less in view of obtaining a high degree of whiteness. When it is desired to improve the chemical strengthening property by ion exchange, it is preferably 3% or more.

MgO functions together with P ₂ O ₅ and Na ₂ O to facilitate the pulverization and improve the whiteness. However, when MgO is too much, the pulverization does not occur easily. The content of MgO is preferably 18% or less, more preferably 15% or less, and still more preferably 13.5% or less. The lower limit of the content of MgO is preferably 3% or more in that the effect of improving whiteness is easily obtained.

CaO, SrO, and BaO are not essential components, but are components having an effect of increasing the whiteness and preferably contain at least one of them in order to obtain high whiteness.

When CaO is contained, its content is preferably 1% or more, and more preferably 2% or more. In order to prevent the release, the content thereof is preferably 7% or less. , More preferably not more than 6%, and even more preferably not more than 5%. Here, the term &quot; devitrification &quot; means a phenomenon in which transparency is lost due to precipitation of crystals (the same applies hereinafter).

When SrO is contained, its content is preferably 1% or more, and more preferably 2% or more. Further, in order to prevent the occurrence of erosion, the content thereof is preferably 10% or less. More preferably, it is 8% or less.

When BaO is contained, its content is preferably 1% or more, and more preferably 3% or more. Further, in order to prevent the film from being devitrified, its content is preferably 12% or less. , More preferably 10% or less, and further preferably 9% or less. BaO is larger than other alkaline earth metal oxides for promoting whitening.

The total content of these components, CaO + SrO + BaO, is preferably 1 to 22%. In order to obtain a high degree of whiteness, the total content of these components is preferably at least 1%, more preferably at least 2%, further preferably at least 3%. The content of the total amount is preferably not more than 22%, more preferably not more than 15%, further preferably not more than 13%, particularly preferably not more than 12%, so that the stability of the glass is improved and the glass is not devitrified. Or less, more preferably 10% or less.

The total RO of the content of MgO, CaO, SrO, and BaO is preferably 5% or more so as not to increase the melting temperature and lower the melting viscosity. , More preferably not less than 10%, still more preferably not less than 12%. In order to prevent the film from being devitrified, the total content thereof is preferably 25% or less, more preferably 22% or less, further preferably 20% or less.

The CaO content and the specific CaO / RO ratio of RO are preferably not more than 0.7, more preferably not more than 0.6, and even more preferably not more than 0.5 in order not to cause any erosion.

ZrO ₂ is not essential, but contributes to improvement of chemical durability. The content thereof is preferably not more than 5%, more preferably not more than 4%, further preferably not more than 3% from the viewpoint of not lowering whiteness. In the case of containing ZrO ₂ in order to improve the compressive stress when ion-exchanged, the content thereof is preferably 0.5% or more.

The content of Na ₂ O is preferably 5% or more in order to improve the melting property of the glass. It is preferably 8% or more. The content of Na ₂ O is preferably 15% or less in order to maintain weatherability and to maintain whiteness. More preferably, it is 14% or less. When increasing the surface compressive stress by the ion exchange treatment and increasing the strength of the glass, the content of Na ₂ O is preferably 6% or more. , More preferably not less than 7%, still more preferably not less than 8%.

P ₂ O ₅ is a basic component which remarkably promotes whitening of glass by pulverization, and its content is preferably 2% or more, and more preferably 3% or more. The content thereof is preferably 10% or less, and more preferably 8% or less, in order to suppress volatilization, reduce white unevenness, and enhance the appearance of the glass.

When CaO is contained, the content of CaO / P ₂ O _{5 in terms} of the content and the content of P ₂ O ₅ is preferably 1.5 or less in order to suppress devitrification. More preferably 1.2 or less.

According to the present invention, by using a sodium source such as sodium carbonate, a phosphoric acid source such as an aqueous solution of phosphoric acid, and magnesium hydroxide in addition to silica as a glass raw material composition, good assembling property can be obtained, Is obtained. For example, a disodium hydrogenphosphate hydrate compound, a magnesium phosphate hydrate compound, and a magnesium hydrogen phosphate hydrate compound are produced by reacting sodium carbonate, an aqueous phosphoric acid solution, and magnesium hydroxide during granulation, and these products function as a binder in the assembly, It is presumed to manifest the strength of the assembly.

[Particle size of glass raw material assembly]

The average particle size (D50) of the assembly is not particularly limited, but is preferably 300 m or more, more preferably 500 m or more, from the viewpoint of preventing scattering of raw materials. In addition, from the viewpoint of quick melting, it is preferably 2 mm or less, more preferably 1.5 mm or less.

The size of the assembly is preferably selected within the above range according to the method of manufacturing the molten glass using the assembly.

When the assembly is used in a method of melting by a melting method not depending on the below-mentioned air-blowing method, when the average particle size (D50) of the assembly is 1 mm or more, generation of bubbles in the molten glass is suppressed easy.

When the assembly is melted by the air melting method, the average particle size (D50) of the assembly is preferably 1000 占 퐉 or less, more preferably 800 占 퐉 or less. When the average particle diameter of the assembly is 1000 占 퐉 or less, vitrification progresses sufficiently inside the assembly when melted in a pneumatic heating apparatus, which is preferable.

&Lt; Production method of glass raw material assembly &gt;

The method for producing an assembly of the present invention has an assembling step of assembling a glass raw material composition in the presence of water. If necessary, it is preferable to have a heating and drying step for further heating and drying.

As a method of supplying water to the glass raw material composition, a method of adding a part of the glass raw material as an aqueous solution may be used.

The assembling process can be carried out by appropriately using a known assembling method. For example, a method of crushing a molded body obtained by a power assembly method, a stirring assembly method, a compression assembly method, or compression molding is preferably used. A motorized assembly method is preferable in that it is easy to produce a homogeneous assembly having a relatively small particle diameter.

[Electric assembly method]

In the motor-assisted assembly method, a container containing a raw material to which a water or a binder is added is rotated to rotate the particles on the wall surface, and other particles are adhered to the periphery of the particles to become nuclei. A stirring blade or a chopper can be mounted on the container for electric assembling. The assembly which has been excessively grown by the stirring wing or the chopper is shredded, and an assembly of an appropriate size is obtained.

In the electric transfer assembly method, for example, a powder in a glass raw material composition is placed in a container of a motorized assembling device, and the container is vibrated and / or rotated to mix and stir the raw material powder, Method is preferable.

As the container of the motor-driven assembling device, a rotary container in a plate shape, a cylindrical shape, a circular shape, a vibrating container, or the like can be used, and is not particularly limited.

The motor-driven assembling device is not particularly limited, and may include, for example, a container that rotates with the inclination direction with respect to the vertical direction as a rotation axis, and a rotary blade that rotates in the container in the opposite direction to the container about the rotation axis Etc. may be used. Specific examples of such a motor-driven assembling device include an Irish intensive mixer (trade name: manufactured by Nippon Irihisa) and the like.

Although the order of introduction of the glass raw material into the granulating device is not particularly limited, in the case of using the aqueous phosphoric acid solution, a method of preliminarily mixing the powdery raw material such as silica and then adding the aqueous phosphoric acid solution and water can prevent local aggregation . Further, in the case of using sodium hydroxide, a method of preliminarily mixing powder containing silica and aluminum hydroxide, followed by a method of adding an aqueous solution of sodium hydroxide or a method of adding granular sodium hydroxide and water prevents local aggregation It is preferable.

If the amount of water used is too large, it takes a long time for drying. However, if the amount of water is too small, the strength of the assembly is insufficient.

For example, the amount of water present at the time of granulation is preferably 5 to 25 parts by mass, more preferably 6 to 15 parts by mass, per 100 parts by mass of the total of the solid content of the glass raw material composition.

If the amount of water relative to the solid content of the glass raw material composition is insufficient, it is difficult to obtain a rigid assembly, and if it is excessive, it is likely to adhere to the surface of a device such as a mixer at the time of mixing.

The particle size of the assembly can be controlled according to the strength of stirring and stirring time.

It is preferable to heat-dry the obtained particles after assembling with a motorized assembling device. It can be carried out by a known heat drying method. For example, a method of heating at a temperature of 100 ° C to 200 ° C for 1 hour to 12 hours using a hot-air dryer can be used.

&Lt; Production method of molten glass &gt;

The method for producing a molten glass of the present invention has a glass melting step (hereinafter also referred to as a melting step) in which an assembly obtained by the present invention is heated to be a molten glass. The melting process may be carried out by using a crucible furnace or a Siemens type glass melting furnace, or may be performed by electric melting. All can be carried out by a known method.

[Melting process]

In the melting process, when the molten glass already melted in the glass melting furnace exists, the assembly is put on the surface of the molten glass, and the assembly is referred to as a batch (also referred to as a batch pile) And the molten glass is gradually heated from the surface of the lump to form a molten glass.

Alternatively, the assembly is put into a raw material layer formed on the molten glass liquid surface, and the molten glass is gradually melted from the portion contacting with the molten glass heated by electric melting or the like.

In the case of producing a large amount of glass using a large-sized apparatus, the raw material batch and the cullet obtained by crushing a glass plate or the like are mixed and introduced. Since the assembly obtained by the present invention has high strength, it is preferable that the raw material batch made of the assembly obtained by the present invention and the cullet are mixed and injected without collapsing.

[Air Melting Method]

In an embodiment of the method for producing a molten glass of the present invention, the assembly obtained by the present invention may be formed into a molten glass particle by the air-phase melting method and a step of integrating the molten glass particles into a molten glass.

Specifically, the assembly is first introduced into the high-temperature vapor-phase atmosphere of the air heating apparatus. The pneumatic heating apparatus may be any known one. Since the assembly obtained by the present invention has excellent strength, generation of fine particles is suppressed even when collision occurs between the particles and the particles and the inner wall of the conveying path at the time of conveyance or introduction.

Then, the molten glass particles melted in the air heating apparatus are accumulated to obtain a molten glass, and the molten glass taken out from the molten glass is supplied to the next molding step. Examples of the method of collecting the molten glass particles include a method of collecting molten glass particles falling under their own weight in a gas-phase atmosphere in a heat-resistant container formed under a gas-phase atmosphere.

&Lt; Production method of glass article &gt;

The method for producing a glass article of the present invention is a method for producing a glass article using the method for producing a molten glass of the present invention.

First, the molten glass obtained in the melting step is formed into a desired shape in the molding step, and then, if necessary, is subjected to the cooling in the quenching step. Thereafter, if necessary, a post-process is performed by a known method such as cutting or polishing in the post-processing step to obtain a glass article.

When the glass article is in the form of a plate, the molding step is molded into a desired shape by a known method such as a float method, a down-draw method, a slit-down draw method, a fusion method, a roll-out method, A glass article is obtained by quenching.

In the case of producing a glass article of white color, a post-processing step is carried out after the quenching step, if necessary, followed by a pulverization step of heat-treating and dispersing the glass. For the heat treatment for the powder, known methods can be used. As the conditions of the heat treatment for dispersing the glass, a temperature of 50 to 400 DEG C higher than the glass transition point or the sag temperature is preferable, and a temperature higher than 100 DEG C to 300 DEG C is more preferable. The time for heat-treating the glass is preferably 1 to 64 hours, more preferably 2 to 32 hours. From the viewpoint of mass productivity, the time is preferably 24 hours or less, more preferably 12 hours or less.

In addition, the glass may be dispersed by heat treatment for melting, homogenizing, shaping, cooling, or shaping without performing a process of specially dispersing in the step of performing melting, homogenization, molding, . In this case, the pulverizing step of pulverizing the glass is included in the step of melting or the like.

Whether or not the glass is dispersed can be judged by a scanning electron microscope (SEM). That is, when glass is separated, it can be observed that the glass is divided into two or more phases when observed with an SEM.

In the case of producing a white chemically reinforced glass article, a chemical strengthening step is carried out in which a desired shape is formed by a molding process and then an ion exchange process is performed. Further, in the case of a pulverizing step, the chemical strengthening step is carried out after the pulverizing step.

As a method of ion exchange treatment, for example, Na ions in the glass surface layer and K ions in the molten salt are ion-exchanged by a known method such as immersing the glass in a molten salt of potassium nitrate (KNO ₃ ) which has been heated.

Example

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Production Examples 1 to 9 are Examples and Production Examples 10 to 12 are Comparative Examples.

[Glass Composition]

As the composition of the glass to be obtained from the glass raw material assembly, five of the grasses A to E shown in Table 1 were used. The glass composition in Table 1 is an indication of mole percentage based on oxide (unit: mole%).

[frit]

Table 2 shows the raw materials used in Plain A to E, respectively.

&Lt; Preparation Examples 1 to 12: Preparation of glass raw material assembly &gt;

[Formulation of glass raw material composition]

Tables 3 and 4 show the blend of glass raw materials in each example. In the case of caustic soda (aqueous solution of sodium hydroxide), the amount of solid content was the amount of NaOH as the sodium source, and the remainder was the amount of water. Also in the aqueous solution of phosphoric acid, the amount of solid content was determined as the amount of phosphoric acid (H ₃ PO ₄ ) as the phosphoric acid source, and the remainder was the amount of water.

A glass raw material assembly was prepared from the formulations shown in Tables 3 and 4 (solid content and water) and manufacturing conditions (assembly time). Table 5 shows the composition (units: parts by mass) of the glass raw material compositions in Tables 3 and 4 in terms of the mass percentage with respect to the total solid content (unit: mass%).

As the pelletizer, an Irih intensive mixer (product name, manufactured by Nippon Irihisa, model: R02 type, capacity 5 L, rotor: star type) was used.

Specifically, the amount of water to be added in addition to the liquid raw material is calculated so that the total solid content of the glass raw material to be assembled and the ratio of water to the total amount of water become the values shown in the table, and the water and the liquid raw material are mixed in advance, do.

The raw materials other than the liquid raw materials were put into a pellet mill and premixed for 60 seconds at a fan rotation number of 42 rpm and a rotor rotation number of 900 rpm. After premixing, water and an aqueous solution of phosphoric acid were added while maintaining the number of revolutions of the fan at 42 rpm. Thereafter, the rotor was rotated at 3000 rpm, assembled at the assembly time shown in the table, taken out of the pelletizer, and dried in a lathe-type dryer at a temperature of 120 캜 for 15 hours to obtain a glass raw material assembly.

Photographs of the assemblies obtained in Production Examples 2, 5, 7, 8, 11 and 12 are shown in Figs. A unit length of 1 mm is displayed on the upper left of each photograph.

<Evaluation>

[D50 (unit: 占 퐉) of the assembly]

The obtained assembly was subjected to measurement of particle size distribution and average particle size (D50) using an automatic body classification meter (product name: Robot Shifter, RPS-105, manufactured by Seishin Enterprise Co., Ltd.). The sizes of the eight sieves used in the automatic body classification meter were 106 mu m, 250 mu m, 355 mu m, 500 mu m, 710 mu m, 1000 mu m, 1400 mu m, and 2000 mu m. The measurement results of D50 are shown in Tables 3 and 4.

[Differential rate (unit: mass%)]

15 g of the obtained assembly was shaken for 60 minutes with a shaker (product name: AS-1N manufactured by Azuwa Yarn) for 60 minutes and then the content (unit: mass% , I.e., the differential fraction was measured. The results are shown in Tables 3 and 4. The lower the differential fraction, the higher the strength of the assembly.

[Assemblability]

Even when assembled at the assembly time shown in Tables 3 and 4, the case where the granules do not grow and the case where the granules are mostly grown is x (poor), and the case where the granules grow to obtain an assembly is evaluated as Good (good).

[Solidification after assembly]

About 2 kg of the assembly obtained by the above-described assembly was placed in a closed plastic bag and opened for 1 hour, and then opened. The result was that the assemblies were fixed to each other, (Good) that the bag was easily detachable by an impact of shaking the plastic bag.

In Table 3, in Production Example 1, solidification occurred severely and D50 and the differential fraction could not be measured. In Production Examples 10 to 12, D50, differential fraction and solidification were not measured because a predetermined assembly was not obtained. Therefore, these are shown as &quot; - &quot; in these production examples.

As shown in Tables 3, 4 and 5, in Production Examples 1 to 9 in which the content of magnesium hydroxide (Mg (OH) ₂ ) was 3.6 to 8.4 mass% with respect to the total solid content of the glass raw material composition, Were grown to obtain a good glass raw material assembly. On the other hand, if the content of magnesium hydroxide is less than 3.6% by mass, the granulation property is markedly lowered and the granulation is difficult. If it is more than 8.4 mass%, the adhesive force becomes too strong, so that the assemblies are agglomerated abruptly to form a large mass, and it is practically difficult to control the diameter of the assembly.

Production examples 1 to 9 wherein the content of magnesium hydroxide (Mg (OH) ₂ ) is 3.6 to 8.4% by mass and the content of phosphoric acid (H ₃ PO ₄ ) is 4.7 to 16.9% by mass based on the total solid content of the glass raw material composition An assembly having good assemblability was obtained.

On the other hand, even though the content of phosphoric acid (H ₃ PO ₄ ) was in the range of 4.7 to 16.9 mass%, it was difficult to assemble in Examples 10 to 12 in which the content of magnesium hydroxide (Mg (OH) ₂ ) was less than 3.6 mass%.

Wherein the content of magnesium hydroxide (Mg (OH) ₂ ) is 4.1 to 7.7 mass% and the content of phosphorus oxide (H ₃ PO ₄ ) is 7.5 to 8.4 mass% based on the total solids content of the glass raw material composition In Production Examples 4 to 8, in which no solidification occurred after assembly, a better assembly was obtained. Also, the assembly had a fine fraction of less than 1% and a sufficient strength.

Industrial availability

By the manufacturing method of the present invention, it is possible to obtain a preferable glass raw material assembly used for manufacturing glass of glass containing at least SiO ₂ , P ₂ O ₅ , and Na ₂ O. In addition, when the glass raw material assembly is melted, it is possible to prevent the assembly from collapsing to generate a large amount of fine powder, and to suppress the solidification of the assembly. Therefore, the glass raw material assembly obtained by the production method of the present invention is easy to carry and does not produce fine powders even if it is conveyed or introduced into a high-temperature vapor atmosphere, and glass production using glass melting furnace or other glass melting furnace Can be preferably used.

The entire contents of the specification, claims, drawings and summary of Japanese Patent Application No. 2015-183969 filed on September 17, 2015 are hereby incorporated herein by reference as the disclosure of the present invention.

Claims (11)

A method for producing a glass raw material assembly by assembling a glass raw material composition containing at least silica, a sodium oxide source, a magnesium oxide source and a phosphoric acid source in the presence of water,
Wherein the glass raw material composition contains 3.6 to 8.4 mass% of magnesium hydroxide based on the total solid content of the glass raw material composition. The method according to claim 1,
Wherein a phosphoric acid aqueous solution is used as the phosphoric acid source and the content of phosphoric acid with respect to the total solid content of the glass raw material composition is 4.7 to 16.9 mass%. 3. The method according to claim 1 or 2,
Wherein the content of magnesium hydroxide in the total solid content of the glass raw material composition is 4.1 to 7.7 mass%. 4. The method according to any one of claims 1 to 3,
Wherein sodium carbonate and / or sodium hydroxide is used as said sodium oxide source. 5. The method according to any one of claims 1 to 4,
Wherein the D50 representing the average particle size of the silica is 5 to 350 占 퐉. 6. The method according to any one of claims 1 to 5,
Wherein D50, which represents the average particle size of the glass raw material assembly, is 300 占 퐉 to 2 mm. 7. The method according to any one of claims 1 to 6,
Wherein the composition of the glass obtained from the glass raw material assembly is expressed as a molar percentage based on oxide,
The content of SiO ₂ is 50 to 74%
The content of B ₂ O ₃ is 0 to 8%
The content of Al ₂ O ₃ is 1 to 8%
The content of MgO is 3 to 18%
The content of CaO is 0 to 7%
The content of SrO is 0 to 10%
The content of BaO is 0 to 12%
The content of ZrO ₂ is 0 to 5%
The content of Na ₂ O is 5 to 15%
The content of P ₂ O ₅ is 2 to 10%
The total of other components is 9% or less,
The total content of CaO, SrO and BaO is 1 to 22%
The total RO of the contents of MgO, CaO, SrO and BaO is 5 to 25%
Wherein the CaO / RO CaO / RO ratio is less than or equal to 0.7. A method for producing a glass raw material assembly according to any one of claims 1 to 7, comprising the steps of: preparing a glass raw material assembly; and melting the obtained glass raw material assembly to obtain a molten glass Way. 9. The method of claim 8,
Wherein the glass melting step includes a step of putting the assembly on the molten glass liquid surface in the melting furnace. 10. The method of claim 9,
Wherein the glass melting step comprises the steps of melting the assembly in a gaseous atmosphere to obtain molten glass particles, and collecting the molten glass particles to obtain a molten glass. A method for producing a glass article using the method for producing a molten glass according to any one of claims 8 to 10,
A glass melting step, a molding step for molding the obtained molten glass, and a quenching step for quenching the glass after molding.

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