JPH068190B2 - Crystallized glass material and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a crystallized glass material used as a building material, a wall material, and the like, and a method for producing the same.

(Prior Art) Conventionally, as a preferable method for producing a crystallized glass material, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent Publication No. 48-78217, glass powder particles having a specific composition are accumulated in a refractory mold, and each mold is heated to a temperature higher than the glass softening point to soften the glass powder particles and melt them. There is a method of depositing and crystallizing (hereinafter referred to as an integration method).

According to this method, a glass powder for pattern formation containing an appropriate coloring component is added to the glass powder for base formation, and the powder is accumulated and heat-treated to have an arbitrary color pattern. There is an advantage that a crystallized glass material can be easily obtained.

(Problems to be Solved by the Invention) However, according to the integration method, during the heat treatment, the glass particles are softened and fused almost at the same time, so that the air present between the particles is trapped in the softened fused body. , Remain as bubbles. The smaller the particles of the powdery particles are, the larger the amount of the air bubbles is generated, and the air bubbles are agglomerated with each other to form many pores.

The bubbles and pores in the softened melt expand during the heat treatment, which causes swelling and cracks in the crystallized glass material. In addition, since crystallized glass materials are often used as plate materials by smoothing the surface, if glass cells have many air bubbles or pores, the surface after polishing will be dented due to air bubbles or pores. Are exposed, resulting in product defects. Further, the bubbles and pores cannot bear the stress acting on the member, which causes a decrease in strength.

In addition, since the integration method softens and crystallizes the aggregate of glass powder particles, it is necessary to prevent the shape of the aggregate from being deformed due to the softening of the aggregate during heat treatment. There must be. That is, from the accumulation of the glass powder particles to the completion of the heat treatment, it must be handled in units of molds, the handling is complicated, and the productivity is poor. In addition, a large number of expensive heat-resistant molding dies must be prepared, which increases equipment costs.

The present invention has been made in view of the above problems, and a colored glass material that can be easily provided with a color pattern and that can suppress the inclusion of bubbles as much as possible, and the same glass that does not require handling for each molding die. An object of the present invention is to provide a method for manufacturing a material.

(Means for Solving the Problems) The crystallized glass material of the present invention made to achieve the above-mentioned object is a low softening point glass powder and a high softening point glass powder after softening and fusion of the low softening point glass powder. A crystallized glass material obtained by fusion-integration and crystallization, wherein the low-softening point glass powder is mainly composed of wt% SiO ₂ : 65-80%, CaO: 5-10% Na ₂ O + K ₂ O: 10 to 20%, MgO: 2 to 8%, and the main component of the high softening point glass powder is wt% SiO ₂ : 65 to 80%, Al ₂ O ₃ : 25% or less Na ₂ O + K ₂ O: 5 The composition of the present invention is composed of ˜15% glass powder having a high softening point fusion bonding property and alumina powder.

Further, as a preferable production method, the main component is by _{weight%, SiO 2: 65~80%,} CaO: 5~10% Na 2 O + K 2 O: 10~20%, MgO: Low is 2% to 8% softening point and the glass powder, SiO main component in _{weight% 2: 65~80%, Al 2} O 3: 25% or less Na ₂ O + K ₂ O: high softening point fusible glass powder and the alumina is 5-15% Powder mixed with a high softening point glass powder consisting of powder is pressure-molded at a temperature not lower than the softening point of the low softening point glass powder and lower than the crystallization start temperature of the low softening point glass powder, and the high softening point glass powder A glass powder compact is obtained by softening, adhering or fusing a low softening point glass powder around, and the compact is a softening point of the glass powder having a low softening point or higher than the crystallization start temperature of the fusible glass powder. The invention is constituted by heating to the following temperature for crystallization.

(Operation) Since the crystalline glass material of the present invention is a low-softening point glass powder and a high-softening point glass powder, which are crystallized by fusion-melting and integrating the low-softening point glass powder after softening and fusion. During the softening and fusion of the glass powders, the air present between the glass powders is discharged to the outside of the glass powders along the particle surface of the unsoftened high-softening point glass powders. Therefore, bubbles are unlikely to remain in the fused body of both glass powders, and as a result, bubbles and pores are eliminated as much as possible in the crystallized glass material of the present invention.

The low softening point glass powder used in the present invention is a composition of ordinary soda lime glass, on the other hand, the high softening point fusible glass powder, which is the main component of the high softening point glass powder, has a low softening point of SiO ₂ content. Since it is in the same range as the glass powder, it is softened even at a temperature above the softening point of the low-softening point glass powder and below the crystallization start temperature of the low-softening point glass powder. Diffusion transfer of network-modifying ions such as Na and K to the point-melting glass powder easily occurs. As a result, the softening temperature is lowered in the component diffusion region of the high-softening fusible glass powder, and the low-softening point glass powder and the high-softening point glass powder that have been softened and fused are easily fused and integrated.

The reasons for limiting the main components of the low softening point and high softening point fusible glass powders are described below. The unit is% by weight.

A. Low softening point glass powder SiO _2: SiO ₂ crystal is less than 65% to 80% 65% hardly precipitated, whereas exceeding the softening point is increased to 80%, requires a high temperature heat in the heat treatment, the production is not preferable.

CaO: 5-10% If it is less than 5%, the softening point becomes high, while if it exceeds 10%, it becomes Si.
O ₂ crystals are less likely to precipitate.

Na ₂ O + K ₂ O: 10-20% If the content is less than 10%, the softening point becomes high, while if it exceeds 20%, Si
O ₂ crystals are less likely to precipitate.

MgO: 2 to 8% If less than 2%, the growth of SiO ₂ crystals will be too fast, and crystallization will start before sufficient densification by softening fusion. On the other hand, if it exceeds 8%, it becomes difficult to deposit SiO ₂ crystals.

B. High softening point fusible glass powder SiO ₂ : 65-80% If less than 65%, SiO ₂ crystals are hard to precipitate, while if it exceeds 80%, the softening point becomes too high and the components diffuse with the low softening point glass powder. Is less likely to occur.

Al ₂ O ₃ : 25% or less Al ₂ O ₃ acts to raise the glass softening point, but 25%
If it exceeds, it becomes difficult to deposit SiO ₂ crystals.

Na ₂ O + K ₂ O: too high softening point is less than 5-15% 5%, diffusion of components of the low-softening point glass powder is less likely to occur. On the other hand, if it exceeds 15%, the softening point becomes too low, and the softening temperature may become lower than the crystallization start temperature of the low softening point glass powder.

The main components of the low softening point and high softening point fusible glass powders are as described above, but in addition, it is acceptable to include a coloring agent and a component that is usually added in the glass industry field for adjusting physical properties.

The high softening point glass powder includes alumina powder. Alumina powder is crystallized (Na ₂ O ₂₎ due to the diffusion of components between the alumina powder and the low softening point glass powder in the softened state at the grain boundaries.
・ Al ₂ O ₃・ 2SiO ₂ crystallizes) to form a strong bond, and the coefficient of linear expansion is 10% or more lower than that of the low softening point glass powder. Therefore, during the cooling process after crystallization, Compressive stress can remain in the crystallized glass material, and the crystallized glass material can be strengthened. In addition, since the coefficient of thermal expansion of the crystallized glass material itself can be reduced, the thermal shock resistance becomes excellent. Since the alumina powder deteriorates the gloss of the crystallized glass material, it is preferable to keep the content of the low-softening point glass powder and the high-softening point glass powder at 10% by weight or less based on the total amount. However, in order to obtain an effective strengthening effect due to the compressive residual stress, it is desirable to add 1% by weight or more.

Further, according to the production method of the present invention, the mixed powder of the high softening point glass powder and the low softening point glass powder is equal to or higher than the softening point of the low softening point glass powder and is equal to or lower than the crystallization start temperature of the low softening point glass powder. Since the pressure is applied at the temperature of 1, the low softening point glass powder is softened and fused while being adjacent to the high softening point glass powder, and adheres to the high softening point glass powder. At this time, the air existing between the glass powders is discharged to the outside through the surface of the unsoftened high-softening point glass powder. Further, when the heating temperature is relatively high in the temperature range, diffusion of components between the softening fusion portion of the low softening point glass powder and the surface of the high softening point glass powder to which the portion adheres, migration occurs, and the component The diffusion region is softened and the high softening point glass powder and the softening fusion-bonded portion of the low softening point glass powder are fused.

In this way, the mixed powder of the low softening point glass powder and the high softening point glass powder is adhered or fused and integrated to form a dense glass powder compact. This glass powder compact has a sufficient strength required for handling and can be handled alone.

Next, since the glass powder compact is heated to a temperature equal to or higher than the crystallization start temperature of the low softening point glass powder and equal to or lower than the softening point of the high softening point fusible glass powder, the low softening point glass powder is used in the temperature rising process. The fusion with the high softening point fusion-bondable glass powder proceeds, and the softened fusion portion expands. Further, the high softening point fusible glass powder and alumina powder in the unsoftened state serve as an aggregate, and the softened and fused portions of the low softening point glass powders are held in a state where the shape of the molded body is maintained. Also, crystals precipitate and grow in the softening fusion-bonded portion in the component diffusion region with the high softening point glass powder.

Therefore, it is not necessary to subject the glass powder molded body to the crystallization heat treatment together with the mold required for the pressure molding of the mixed powder, and the glass powder molded body can be handled alone, and the work is easy and the productivity is excellent. Further, it is not necessary to prepare a large number of expensive heat resistant molds.

After the crystallization heat treatment, it is cooled to room temperature. During this time, since the alumina powder portion has a smaller coefficient of thermal expansion than the matrix, compressive stress remains in the crystallized glass and the material is strengthened.

(Example) Below, the crystallized glass material of this invention is demonstrated with the manufacturing method.

First, the glass powder used in the present invention will be described.

The main components of the low softening point glass powder and the high softening point fusible glass powder are as described above, but it is desirable to adjust the components of the latter so that the glass softening point thereof is about 800 ° C. or higher. This is because the low softening point glass powder has a composition of ordinary soda lime glass and has a softening point of 600 to 750 ° C and a crystallization start temperature of about 800 ° C or less.

The glass powder can be obtained by melting glass having the desired composition, water-crushing it, and further crushing it. As the low softening point glass powder raw material, cullet (scrap glass) of soda-lime glass is used. The high softening point fusible glass powder may be crushed perlite (pearlite). Perlite contains more than 10% of Al ₂ O ₃ , has a softening point of about 900 ° C. or more, is supplied to the market in large amounts as aggregates, etc., is easily available, and is excellent in economic efficiency.

It should be noted that naturally occurring perlite has a layered structure, and although it has the same components as those of artificially manufactured glass, the properties are slightly different, but in the present invention, such a glass is included. Perlite contains 3-5% of water between layers, but is dehydrated during heat treatment. In addition, the softening point is higher than that of artificial glass of the same component.

Regarding the particle size of the low softening point and high softening point glass powders, the smaller the particle size and the larger the amount thereof, the easier the softening and fusion of the low softening point glass powders, and the easier the fusion with the high softening point glass powders. As a result, densification and crystallization of the glass powder molded body are promoted. Therefore, it is desirable that the particle size of the glass powder is such that the powder having a particle size of 200 mesh or less occupies 80% or more (preferably 90% or more).
It should be noted that the finer the alumina powder is, the finer the grain size becomes, so that the gloss becomes worse, but the finer the price, the higher the price becomes.

The mixing ratio of both powders in the mixed powder of the low softening point glass powder and the high softening point glass powder containing the alumina powder is:
It is desirable that the low softening point glass powder is 20 to 90% by weight. If it is less than 20%, the softening fusion with the high softening point glass powder is insufficient and the glass powder compact is insufficiently densified. In addition, the amount of crystals is insufficient and the strength is reduced. On the other hand, 90
When it exceeds%, the shape retention of the glass powder compact during heat treatment becomes insufficient, and the function of discharging bubbles in the compact is insufficient.

It is possible to use the colored glass powder having the same softening point glass powder and / or the high softening point fusible glass powder having the same components except for the content of the coloring component. By using a mixed powder of such a low softening point colored glass powder and a high softening point colored glass powder (hereinafter referred to as a colored mixed powder), or by using a combination of a plurality of types thereof,
Various colored crystallized glass materials and colored crystallized glass materials can be obtained.

An additive mixed powder obtained by adding and mixing a colorant of metal oxide (usually a fine powder of 200 mesh or less) to a mixed powder of a low softening point glass powder and a medium softening point glass powder containing no coloring component. It is also possible to produce a colored crystallized glass material by using. The colorant is added in a range that does not deteriorate the physical properties (particularly strength) required for the crystallized glass material, and an example of the addition amount is shown below. The addition amount is based on the added mixed powder, the unit is% by weight
Is.

Cr ₂ O ₃ , CuO, MnO ₂ ... 1% or less CoO ... 3% or less FeO, Fe ₃ O ₄ , Fe ₂ O ₃ ... 10% or less In addition, in order to form a spotted colored pattern, 4 to 100 mesh The coarse-grained low softening point and / or high softening point fusible glass powder may be used. As described above, the amount of coarse colored glass powder used is preferably such that the glass powder occupies 80% or more of the powder of 200 mesh or less, so the total amount of the powder is kept to 20% or less. It is preferable.

In order to produce the crystallized glass material of the present invention, the mixed powder described above (hereinafter, when referred to as mixed powder, colored mixed powder,
Includes additive powder mix. First, a glass powder molded body is molded by (1).

As a method for molding a glass powder molded body, for example, as shown in FIG. 1, after the mixed powder 2 is put into a molding die 1 (mold),
A method in which the upper mold 3 is fitted and pressure-molded at room temperature (normal-temperature pressure molding method), the mixed powder 2 is heated to a temperature above the softening point of the low softening point glass powder and below the crystallization start temperature of the powder (hereinafter , Densification temperature) and pressure molding (high temperature pressure molding method). After the glass powder compact is molded, it is taken out of the mold, placed in a heat treatment furnace, and subjected to the heat treatment described later. After molding, it is possible to perform heat treatment while still in the mold, but the handling becomes complicated,
A mold with good heat resistance is also required.

In the case of the cold-pressing method, the powder is usually pressed to such an extent that the powder particles come into contact with each other (relative density is preferably 50% or more),
Further, in order to secure handling strength (bending strength of 10 kgf / cm ² or more is desirable) and improve moldability, a few percent of a binder is added to the mixed powder and mixed. If you want to get a large molded body,
The addition of a binder is indispensable to secure the strength. An organic binder such as polyvinyl alcohol (P
VA) is normally used.

The glass powder compact molded at normal temperature is subjected to heat treatment as shown by the solid line in FIG. The section a is a drying section for removing water and organic solvent in the binder.
The section b is a binder removal section, and by maintaining it at 300 to 400%, the polymer component of the binder is decomposed, gasified and discharged to the outside of the molded body. If the binder remains in the molded body, swelling or cracking occurs in the heat treatment section after the molding, or the physical properties of the product are deteriorated. Therefore, the binder needs to be actively removed. The section c is a densification section, and at the densification temperature (usually 600 to 800 ° C.), the low softening point glass powders are softened and fused, and also adhered or fused to the high softening point glass powder, and further increased in temperature. Fusion progresses. In the figure, c is shown as a continuous temperature rising state, but it may be moved to the next section after being held at a certain temperature within the densification temperature range and sufficiently softened and fused. Section d is a crystallization section, which is a temperature above the crystallization start temperature of the low softening point glass powder and below the softening point of the high softening point fusible glass powder (hereinafter referred to as crystallization temperature, usually 800 to 1000 ° C.). Hold at to crystallize the softened and fused portion. It should be noted that crystallization may be performed at a temperature equal to or higher than the softening point of the high softening point fusible glass powder, but in this case, the glass powder molded body must be heat-treated for each molding die in order to prevent the shape from being deformed. Section e is a slow cooling section.

According to the high-temperature pressure molding method, the glass powder in the mold is pressed at the densification temperature, so that the low softening point glass powders soften and adhere to each other and adhere to the high softening point glass powder without using any binder. A glass powder compact having a relative density of 50% or more and a bending strength of 10 kgf / cm ² or more that can be handled by fusion and can be handled alone can be easily obtained. In this case, rapid heating to the pressure molding temperature may be performed, and molding time may be very short (about several minutes).

After the pressure molding, the glass powder molded body is taken out of the molding die and immediately charged into the heat treatment furnace. However, when the glass powder molded body is once cooled to room temperature, as shown by the broken line in FIG. The subsequent heat treatment can be performed by rapidly heating to the densification temperature, and the heating in the section a to b, which is required in the normal temperature pressure molding method, can be omitted. Since the section a-b usually takes a long time, the high-temperature pressure molding method is extremely excellent in productivity. For example, in order to obtain a plate-shaped crystallized glass material having a size of 700 cm square and a thickness of 20 to 30 mm, section a to b requires 70 to 80 hours, and even if the glass powder compact is dried in advance before heat treatment. , It takes 40 to 50 hours to remove the binder.

In the high-temperature pressure molding method, the mixed powder can be heat-molded by placing the room-temperature mixed powder in a mold at room temperature, heating the mold to the desired temperature, and then applying a pressure of 5 kgf / cm ² or more. A molding method is generally used. In this case, the heating is usually performed by a heater provided in the molding die or by putting the molding die together in a heating furnace. In addition to this, various heat molding methods can be adopted. For example, a method in which a mixed powder heated to a predetermined temperature is put into a molding die at room temperature and pressure-molded. A mixed powder at room temperature is put into a molding die heated to a predetermined temperature, and the mixture is heated and pressed by the heat held by the molding die. Molding method There is a method in which a powder mixture at room temperature is put in a mold at room temperature, and only the surface thereof is heated to a predetermined temperature by electrothermal radiation, infrared radiation, direct heating by a burner, and the like, and pressure molding is performed. Further, it is also possible to heat the mixed powder at room temperature to a predetermined temperature with a pair of hot rolls and to perform pressure molding. Here, the normal temperature includes a state of being preheated at a temperature lower than the softening temperature of the low softening point glass powder.

In order to prevent the low softening point glass powder from sticking, it is desirable that the molding die be subjected to a treatment such as a coating agent such as zircon sand or graphite, a ceramic powder, or a ceramic sheet. .

Next, specific examples will be described.

(1) Various glass powders having the compositions and particle sizes shown in Table 1 were prepared. Incidentally, cullet as a low softening point glass powder raw material,
Perlite was used as a raw material for the glass powder having a high softening point fusion property.

(Note) A ... Low softening point glass powder B ... High softening point fusible glass powder (2) A mixed powder was prepared by mixing the glass powders of A and B in Table 1 with the compound in Table 2 and applying a high temperature of the same table. A plate-shaped glass powder compact having a size of 1050 × 1050 mm (thickness 20 to 25 mm) was manufactured according to the pressure molding conditions. In the table, No. 1 is a comparative example and No. 2 is an example. The purity of the used alumina (Al ₂ O ₃ ) is 99.
7% and the average particle size was 1.8 μm.

(3) After high-temperature pressure molding, take out the No. 1 and No. 2 glass powder compacts from the molding die, insert them into a heating furnace kept at 600 ° C, and soak them, then at 30 ° C / Hr 900 Up to ℃,
After being kept for 4 hours for crystallization, it was gradually cooled.

(4) Table 3 shows the mechanical properties of the obtained crystallized glass material.

According to Table 3, No. 2 according to the example is No. 2 according to the comparative example.
A remarkable improvement in bending strength was observed in comparison with No. 1. Also,
It was confirmed that the linear expansion coefficient of No. 2 was smaller than that of No. 1. Therefore, the crystallized glass materials of the examples are known to be strong against thermal shock. The reason why the linear expansion coefficient increases at 100 to 200 ° C. is that the volume expansion occurs due to the transformation of the SiO ₂ crystal. Also, No. 1 and No.
In both cases, there were no pores or bubbles observed in the tissue with the naked eye.

(5) In addition, when the crystals deposited on the crystallized glass material were identified by powder X-ray diffraction using characteristic X-rays, No. 1 was S
Only iO ₂ crystal was present, but No. 2 is SiO ₂ crystal and Na ₂ O ・ Al ₂ O
₃ · 2SiO ₂ crystal was also observed.

(Effects of the Invention) As described above, the crystallized glass material of the present invention is crystallized by fusion-bonding the low softening point glass powder and the high softening point glass powder after softening and fusion of the low softening point glass powder. Therefore, the air present between the glass powders during softening and fusion of the low softening point glass powders is discharged to the outside along the high softening point glass powder surface in the unsoftened state, and pores and bubbles in the tissue are generated. It will be almost nonexistent.

Further, the low softening point and the high softening point fusible glass powder of the specific composition used in the present invention are easily available, and it is easy to secure the softening temperature difference, and easily fused with each other, productivity,
Excellent economy. In addition, a crystallized glass material having an arbitrary color pattern can be easily obtained by using a desired colored glass powder or a coloring agent.

Furthermore, since the alumina powder is added to the high softening point glass powder, the bond is strengthened by crystallization with the glass powder and the compressive stress can be left in the crystallized glass material, and the strength is improved. It is possible to improve the thermal shock resistance in combination with the decrease in the coefficient of thermal expansion.

On the other hand, according to the production method of the present invention, it is possible to easily obtain a powder compact having high strength that can be handled alone without using any binder, and therefore, the binder removal process that requires a long heating time during the heat treatment. Is unnecessary and is extremely excellent in productivity. Moreover, since the crystallization of the glass powder molded body is performed at a temperature equal to or lower than the softening point of the high softening point fusible glass powder, the inner portion of the unsoftened high softening point fusible glass powder and the alumina powder function as an aggregate. The shape of the compact is maintained even during high-temperature crystallization heat treatment, and the shape does not collapse. Therefore, it is not necessary to subject the molding die to heat treatment, and productivity can be improved and equipment cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die showing a molding procedure of a glass powder compact, and FIG. 2 is a heat treatment diagram showing an example of heat treatment of a crystallized glass material of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Kimura 64, Nishimukaishima-cho, Amagasaki City, Hyogo Prefecture Kubota Iron Works Co., Ltd. Amagasaki Plant (72) Kei Shikata, 64, Nishimukaijima-cho, Amagasaki City, Hyogo Prefecture Kubota Iron Works Co., Ltd. Amagasaki Plant (56) Reference JP-A 63-144142 (JP, A) JP-A 63-17238 (JP, A)

Claims (2)

[Claims] 1. A low softening point glass powder and a high softening point glass powder are fused and integrated after softening and fusion of the low softening point glass powder,
A crystallized glass material obtained by crystallization, wherein the low softening point glass powder is mainly composed of weight% SiO ₂ : 65 to 80%, CaO: 5 to 10% Na ₂ O + K ₂ O: 10 to 20%, MgO: 2 to 8% said high softening point glass powder of SiO main component in _{weight% 2: 65~80%, Al 2} O 3: 25% or less Na ₂ O + K ₂ O: a 5-15% A crystallized glass material comprising a glass powder having a high softening point fusion bonding property and an alumina powder. 2. A main component in _{weight%, SiO 2: 65~80%,} CaO: 5~10% Na 2 O + K 2 O: 10~20%, MgO: low softening point glass powder is 2% to 8% consisting of a high softening point fusible glass powder and the alumina powder is 5-15%: If a main component SiO ₂ by _{weight%: 65~80%, Al 2 O} 3: 25% or less Na ₂ O + K ₂ O The mixed powder with the high softening point glass powder is pressure-formed at a temperature not lower than the softening point of the low softening point glass powder and lower than the crystallization start temperature of the low softening point glass powder, and low softening is performed around the high softening point glass powder. A glass powder compact is obtained by softening and adhering the point glass powder, and the compact is heated to a temperature not lower than the crystallization start temperature of the low softening point glass powder and not higher than the softening point of the high softening point fusible glass powder. A method for producing a crystallized glass material, which comprises crystallizing by crystallization.