JPH02120254A - Crystallized glass material and production thereof - Google Patents

Abstract

PURPOSE:To suppress the inclusion of bubbles by fusing and integrating glass powder having a low softening point and a specific composition and glass powder having high softening point after the softening and welding of the former glass powder and crystallizing the integrated material. CONSTITUTION:Glass powder (powder PL) having low softening point and composed mainly of 65-80wt.% of SiO2, 5-15wt.% of CaO, <=10wt.% of Al2O3, 10-20wt.% of Na2O+K2O and <=10wt.% of MgO and glass powder (powder PH) having high softening point and composed mainly of 50-65wt.% of SiO2, 15-35wt.% of CaO, <=10wt.% of Al2O3 and 10-20wt.% of Na2O+K2O are prepared beforehand. A powdery mixture of the powder PL and the powder PH is compression-molded at a temperature above the softening point of powder PL and below the crystallization initiation temperature of the powder PL to obtain a formed article of glass powder composed of the powder PL attached or fused to the circumference of the powder PH. The formed article is heated and crystallized at a temperature above the softening point of the powder PH. The air existing between the glass particles in the softening and welding of the powder PL is discharged from the article along the surface of unsoftened powder PH.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a crystallized glass material used as a building material, wall material, etc., and a method for manufacturing the same.

(Prior Art) Conventionally, as disclosed in Japanese Unexamined Patent Application Publication No. 48-78217, a suitable method for manufacturing crystallized glass materials involves accumulating glass powder particles of a specific composition in a fire-resistant mold, There is a method (hereinafter referred to as the accumulation method) in which the entire mold is heated to a temperature higher than the glass softening point to soften and fuse the glass powder and crystallize it.

According to this method, a pattern-forming glass powder containing an appropriate coloring component is added to a base-forming glass powder, which is accumulated and heat-treated to form an arbitrary color pattern. It has the advantage that crystallized glass material can be easily obtained.

(Problem to be solved by the invention) However, according to the accumulation method, the glass powder particles are softened and fused almost simultaneously during heat treatment, so the air existing between the powder particles is trapped in the softened and fused body. , and remain as bubbles. The smaller the particles of the powder or granular material, the more these bubbles are generated, and they aggregate together to form large pores.

Bubbles and pores in the softened and fused body expand during heat treatment, which causes blisters and cracks in the crystallized glass material. In addition, since crystallized glass materials are often used as plate materials after polishing their surfaces smooth, if there are many air bubbles or pores in the glass material, dents due to the air bubbles or pores may appear on the surface after polishing. A large number of defects are exposed, resulting in product defects. In addition, air bubbles and pores cannot bear the stress acting on the member, which causes a decrease in strength.

In addition, since the accumulation method softens and crystallizes the aggregate of glass powder particles, it is necessary to prevent shape deformation due to softening of the aggregate during heat treatment. must be provided. That is, the process from the accumulation of the glass powder to the completion of the heat treatment must be handled on a mold-by-molding mold basis, resulting in complicated handling and poor productivity. Furthermore, a large number of expensive heat-resistant molds must be prepared, which increases equipment costs.

The present invention was made in view of such problems, and aims to provide a crystallized glass material that can suppress the inclusion of air bubbles as much as possible, and a method for manufacturing the same glass material that does not require handling each mold. do.

(Means for Solving the Problems) In the crystallized glass material of the present invention, which has been made to achieve the above object, a low softening point glass powder and a high softening point glass powder are bonded together after softening and fusing of the low softening point glass powder. A crystallized glass material formed by fusing and integrating and crystallizing at a temperature higher than the softening point of a high softening point glass powder, the low softening point glass powder having a main component of SiO□ in weight%:
65-80%, 'CaO: 5-15% Alt03
: 10% or less, Na2O+K2O: 10-20%M
gO: 10% or less, the main components of the high softening point glass powder are 5iOz 450 to 65% by weight, and CaO: 15 to 35%A.
t, o3: 10% or less, NazO+KzO: 2-1
The structure of the invention is that it is 0%.

In addition, as a preferred manufacturing method, the main components are Sing: 65-80%, CaO: 5-15%N by weight%.
, o, : 10% or less, Na2O+K2O: 10~
20% MgO: Low softening point glass powder that is 10% or less and the main component is 5iO in weight%
z: 50-65%, CaO: 15-35% Nt03
: 10% or less, Na2O + KzO: 2 to 10% mixed powder with high softening point glass powder is heated 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. Pressure molding is performed to obtain a glass powder molded body in which a low softening point glass powder is softened or fused around a high softening point glass powder, and the molded body is heated to a temperature equal to or higher than the softening point of the high softening point glass powder. The structure of the invention is to crystallize the material.

(Function) The crystallized glass material of the present invention has a low softening point glass powder and a high softening point glass powder that are fused and crystallized after softening and fusing the low softening point glass powder. When the softening point glass powders are softened and fused together, the air existing between the glass powders is discharged to the outside of the glass powder along the particle surface of the unsoftened high softening point glass powder and becomes densified. Therefore, it is difficult for air bubbles to remain in the fused product of both glass powders,
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 has a composition of ordinary soda-lime glass, while the high softening point glass powder has a composition that quickly crystallizes as it softens. By crystallizing at high temperature, the powder itself also crystallizes, and in combination with the densification of the low softening point glass powder, high strength can be easily achieved. The reasons for limiting the main components of each powder are described below. The unit is weight %.

A. Low softening point glass powder Sing: 65-80% If it is less than 65%, crystal precipitation will be rapid, and if it exceeds 80%, the softening point will be high.

CaO: 5-15% If it is less than 5%, crystals will be difficult to precipitate (on the other hand, if it exceeds 15%, crystals will precipitate quickly).

/V20:l: 10% or less The higher the amount of N2O3 added, the higher the softening point.
Keep it below 10%.

Na2O+K2O: 10-20% If it is less than 10%, the softening point will be high, while if it exceeds 20%, the weather resistance will deteriorate.

MgO: 10% or less Because foreign crystals tend to appear, which is not preferable, MgO is kept at 10% or less.

B. High softening point glass powder 5t (h: 50-65% If it is less than 50%, crystal precipitation will be rapid, while if it exceeds 65%, the softening point will be high and it will take time to fuse and integrate with the low softening point glass powder. It takes.

CaO: 15-35% If it is less than 15%, the amount of crystal precipitation will decrease, while if it is 35%
When the temperature exceeds 100%, crystal precipitation becomes faster.

Ajzol: 10% or less The higher the content of N t O, I, the higher the softening point, and it takes time to fuse and integrate with the low softening point glass powder, so it is limited to 10% or less.

Na2O+K2O: 2 to 10% If it is less than 2%, the softening point will be high, while if it exceeds 10%, the softening point will be low, making it easy to cause deformation during crystallization heat treatment.

The main components of the low softening point and high softening point glass powders are as described above, but in addition, coloring agents and other components commonly added in the glass industry for adjusting physical properties are allowed to be included.

Further, according to the manufacturing method of the present invention, the mixed powder of the high softening point glass powder and the low softening point glass powder is prepared at a temperature higher 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. Since the pressure is applied at a temperature of , the low softening point glass powder is adjacent to the high softening point glass powder and is softened and fused by itself, and also adheres to the high softening point glass powder and fuses to the surface of the powder particles. 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 powders.

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

Next, since the glass powder compact is heated to a temperature higher than the softening point of the high softening point glass powder, the fusion of the low softening point glass powder and the high softening point glass powder progresses during the temperature raising process, and
Crystals are formed in the areas where low softening point glass powders are softened and fused together, in the areas where low softening point glass powders and high softening point glass powders are softened and fused together, and in the entire area of the softened high softening point glass powder itself, that is, the glass powder compact. Precipitates and grows. On this occasion,
Since the high softening point glass powder has a composition that quickly crystallizes, even if it crystallizes at a temperature higher than the softening point of the high softening point glass powder, no significant deformation occurs in the glass powder molded body.

Therefore, it is not necessary to subject the glass powder molded body to the crystallization heat treatment together with the mold required for pressure molding of the mixed powder, and the glass powder molded body can be handled independently, making the work easy and excellent in productivity. Further, there is no need to prepare a large number of expensive heat-resistant molds.

(Example) Hereinafter, the crystallized glass material of the present invention will be explained along with its manufacturing method.

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

The main components of the low softening point glass powder and the high softening point 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 initiation temperature of about 800″C or lower.

Glass powder can be obtained by melting glass of the desired composition, pulverizing it, and then crushing it, but soda lime glass cullet (waste glass) is used as a raw material for low softening point glass powder. can do.

Regarding the particle size of the low softening point glass powder and the high softening point glass powder, the smaller the particle size and the larger the amount, the easier the softening and fusing of the low softening point glass powders, and the easier the fusing with the high softening point glass powder. This facilitates the densification and crystallization of the glass powder compact. Therefore, the particle size of the glass powder is 80% or more (
(preferably 90% or more).

The blending ratio of the low softening point glass powder and the high softening point glass powder in the mixed powder is preferably such that the low softening point glass powder accounts for 20 to 90% by weight. If it is less than 20%, there will be insufficient fusion with the high softening point glass powder.
This results in insufficient densification of the glass powder compact. On the other hand, 90
If it exceeds %, the shape of the glass powder molded body during heat treatment will be insufficient, and the air bubbles in the molded body will not be sufficiently discharged.

A colored glass powder containing a coloring component can be used as part or all of the low softening point glass powder and/or the high softening point glass powder. 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 colored mixed powder), or by using a combination of multiple types thereof, various colored crystallizations can be achieved. Crystallized glass materials such as glass materials and colored pattern materials can be obtained.

Additionally, an additive mixed powder is obtained by adding and mixing a metal oxide coloring agent (usually a fine powder of 200 mesh or less is used) to a mixed powder of a low softening point glass powder and a high softening point glass powder that does not contain a coloring component. It is also possible to produce colored crystallized glass materials by using colorants.Colorants are added within a range that does not reduce the physical properties (especially strength) required for crystallized glass materials, but the amount of addition An example is shown below. The amount added is based on the added mixed powder, and the unit is weight%.
It is.

Cr=03, CuO, Mn0z...1% or less CoO...3% or less FeO, Fe3O4, FezOz ''10% or less In addition, to form a spotted colored pattern, coarse grains of 4 to 100 meshes are required. It is sufficient to use a glass powder with a low softening point) or a high softening point.The amount of coarse colored glass powder to be used is as described above. Since it is desirable to have at least
It is preferable to limit the amount to 20% or less based on the total amount of powder.

To produce the crystallized glass material of the present invention, first, a glass powder molded body is molded using the mixed powder (including colored mixed powder and additive mixed powder) described above.

As shown in FIG. 1, a method for forming a glass powder compact is, for example, a method in which a mixed powder 2 is put into a mold 1 (mold), an upper mold 3 is fitted therein, and the molded body is press-molded at room temperature ( The mixed powder 2 is heated at a temperature above the softening point of the low softening point glass powder and below the crystallization start temperature of the same powder (hereinafter referred to as the densification temperature), and is then press-molded. There is a method (high-temperature pressure molding method).After molding, the glass powder molded body is taken out from the mold, charged into a heat treatment furnace, and subjected to the heat treatment described below. Although heat treatment can be performed as is, handling becomes complicated and a mold with good heat resistance is required.

In the case of cold press molding, the powders are usually in contact with each other (relative density of 50% or more is desirable).

) and handling strength (bending strength 10kg)
f/c+11 or more is desirable. ) and to improve moldability, a few percent of binder is added to the mixed powder. When obtaining a large molded body, it is essential to add a binder to ensure strength. Organic binders, such as polyvinyl alcohol (PVA), are usually used.

The glass powder compact formed under pressure at room temperature is subjected to heat treatment as shown by the solid line in FIG.

Section C is a drying section for eliminating moisture and organic solvent in the binder.

Section b is a binder removal section, and by maintaining the temperature at 300 to 400°C, the polymer component of the binder is decomposed, gasified, and discharged out of the molded body. If the binder remains in the molded article, it may cause blistering or cracking in the subsequent heat treatment section or deteriorate the physical properties of the product, so it is necessary to remove the binder almost completely.

Section C is a densification section, where the densification temperature (usually 600
~800'C), the low softening point glass powders soften and fuse together, and also adhere to the high softening point glass powder or fuse to the particle surface. In the figure, C is shown as a continuous temperature increase state, but it may be held at a certain temperature in the densification temperature range to sufficiently soften and fuse, and then move to the next section.

The d section is a crystallization section, where the temperature is higher than the softening point of the high softening point glass powder (hereinafter referred to as crystallization temperature).

) to soften the high softening point glass powder and promote fusion with the already softened low softening point glass powder,
A portion where low softening point glass powders are softened and fused together, a portion where a low softening point glass powder and a high softening point glass powder are fused together, and the softened high softening point glass powder itself is crystallized. In addition, if the crystallization temperature is set significantly higher than the softening point of the high softening point glass powder, the crystallization rate will decrease and the glass powder compact will be more likely to be deformed. It is preferable to set the temperature within a high temperature range of about 200'C from the softening point of (usually between 800 and 1000C).

Section C is a slow cooling section after crystallization.

According to the high-temperature pressure molding method, the glass powder in the mold is pressurized at the densification temperature, so the low softening point glass powders soften and fuse together and adhere to the high softening point glass powder without using any binder. Relative density: 50% or more, bending strength: 10 kg f/
A glass powder compact of c4 or higher can be easily obtained. In this case, it is sufficient to rapidly heat the material to the pressure molding temperature, and the molding time may be very short (about several minutes).

After pressure molding, the glass powder molded body is taken out from the mold and promptly charged into a heat treatment furnace. The subsequent heat treatment can be performed by rapid heating to the densification temperature of , and the heating in the a-b interval required in the room temperature pressing method can be omitted. Since the section a-b usually takes a long time, the high-temperature press molding method has extremely high productivity. For example, 700 cm square, 20-30ffII
It takes 70 to 80 hours for the a-b section to obtain a plate-shaped crystallized glass material with a thickness of 11. Even if the glass powder molded body is dried in advance before heat treatment, it takes 40 to 80 hours to remove the binder. Requires heating for 50 hours.

In the high-temperature pressure molding method, the mixed powder is heated and molded by putting the mixed powder at room temperature into a mold at room temperature, heating the mold together to the desired temperature, and then pressing at a pressure of 5 kg or more. The method is common. In this case, the mold is usually heated by a heater provided in the mold or by placing the mold together in a heating furnace. In addition, various heat forming methods can be used. For example, (1) A method in which a mixed powder heated to a predetermined temperature is placed in a mold at room temperature and pressure-molded.

■ A method in which mixed powder at room temperature is placed in a mold heated to a predetermined temperature, and the powder is heated and pressurized using the heat contained in the mold.

■ A method in which room-temperature mixed powder is placed in a room-temperature mold, and only the surface of the powder is heated to a predetermined temperature using electric radiation, infrared radiation, direct heating with a burner, etc., and pressure molding is performed.

There is. Further, it is also possible to heat the mixed powder at room temperature to a predetermined temperature using a pair of heating rolls and to press-form it. Note that the term "normal temperature" here includes a state where the glass powder is preheated to 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, the mold should preferably be coated with a coating agent such as zirconside or graphite or ceramic powder, or coated with a ceramic sheet. .

Next, specific examples will be described.

(1) Various glass powders having the composition and particle size shown in Table 1 were prepared.

Table 1 (2) A mixed powder was prepared from the glass powder in Table 1 according to the formulation in Table 2, and according to the molding conditions in the same table, 350 x 35
A plate-shaped glass powder compact of 0 ff1ff+ (thickness 20 to 25 M) was manufactured. In the same table, Nα1 is obtained by the cold pressure molding method, and Na2 is obtained by the high temperature pressure molding method. As a binder, a 3% aqueous solution of PVA was used in an amount of 12% based on the weight of the mixed powder.

Table 2 (Note) A...Low softening point glass powder B...High softening point glass powder (3) After molding, the glass powder compact is taken out from the mold and charged into a heating furnace, and the following It was subjected to heat treatment.

<Floor 1> a Drying This was done by step heating.

40℃X10Hr, 80℃X 1011r, 60
''(x5Hr80°CX10Hr, 120℃X5Hr
b Binder removal from 120°C to 400°C at 20°C/Hr 3
It was maintained for 0 hours.

Raise the temperature from 400″C to 600°C at 40°C/Hr,
The temperature of the molded body was maintained for 2 hours to make it uniform.

C densification and crystallization The temperature was raised from 600°C to 900°C at 30°C/Hr, and
Hr was maintained. Then, it was slowly cooled.

Nα2〉 After molding, the molded product taken out from the mold is immediately heated to 6
The sample was placed in a heating furnace maintained at 00°C, held for 2 hours, then heated to 850°C at 30°C/Hr, held for 10 hours, and slowly cooled.

(4) Visual observation of the cross section of the obtained crystallized glass material revealed that there were no bubbles or pores in both No. 1 and Nα2. In addition, when the bending strength was measured, Na 1 was 830
kgf/c+d, No. 2 is 790 kgf/cf
According to the above-mentioned publication, the strength was approximately 450 kgf/cd using the conventional accumulation method, but a significant improvement in strength was observed. In addition, as a result of examining the water absorption rate,
Both values were approximately 0. In addition, powder X using characteristic X-rays
When the precipitated crystals were fixed by line diffraction, they were found to be mainly wollastonite (CaO-5iO2). In addition, cristobalite (Sing) products and diopside (
Some precipitation of MgO-CaO.2Si(h) was also observed.

(Effects of the Invention) As explained above, in the crystallized glass material of the present invention, the low softening point glass powder and the high softening point glass powder are fused and integrated after the low softening point glass powder is softened and fused, and crystallized. When the low softening point glass powders are softened and fused together, the air that exists between the glass powders is discharged to the outside along the unsoftened high softening point glass powder surface, creating pores and There will be almost no bubbles.

In addition, since the high softening point glass powder has a composition that begins to crystallize as it softens, by performing crystallization heat treatment at a temperature higher than the softening point of the high softening point glass powder, the glass powder portion that remains glassy can be removed. The improvement in strength and uniformity is remarkable.

On the other hand, according to the manufacturing method of the present invention, it is possible to easily obtain a strong glass powder molded body that can be handled independently without using any binder. No binder is required, resulting in extremely high productivity. Moreover, even if the glass powder molded body is crystallized at a temperature higher than the softening temperature of the high softening point glass powder, the low softening point glass powder is already in a softened and fused state, and the high softening point glass powder softens and the low softening point It fuses with the glass powder and crystallizes, and even during high-temperature crystallization heat treatment, the shape of the molded body is maintained and deformation is less likely to occur. Therefore, it is not necessary to subject the entire mold to heat treatment, and it is possible to improve productivity and reduce equipment costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a mold showing the procedure for forming a glass powder compact, and FIG. 2 is a heat treatment diagram showing an example of the heat treatment of the crystallized glass material of the present invention.

Claims (2)

[Claims] (1) Crystallized glass formed by fusing and integrating a low softening point glass powder and a high softening point glass powder after softening and fusing the low softening point glass powder, and crystallizing at a temperature higher than the softening point of the high softening point glass powder. The main components of the low softening point glass powder are SiO_2: 65-80% and CaO: 5-1% by weight.
5% Al_2O_3: 10% or less, Na_2O+K_2
O: 10-20% MgO: 10% or less, and the main components of the high softening point glass powder are SiO_2: 50-65%, CaO: 15-35% Al
_2O_3: 10% or less, Na_2O+K_2O: 2~
10% crystallized glass material. (2) Main components are SiO_2: 65-80%, CaO: 5-15% Al_
2O_3: 10% or less, Na_2O+K_2O: 10~
20% MgO: Low softening point glass powder which is 10% or less, and the main components are SiO_2: 50-65%, CaO: 15-35% Al
_2O_3: 10% or less, Na_2O+K_2O: 2~
A mixed powder with 10% high softening point glass powder is pressure-molded 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. A crystallization process characterized by obtaining a glass powder molded body around which a low softening point glass powder is softened and adhered or fused, and crystallizing the molded body by heating the molded body to a temperature equal to or higher than the softening point of the high softening point glass powder. A method for producing glass-cured material.