JPH02255546A - Double-layer crystallized glass material - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks by fusing and integrating a front layer formed of a crystallized glass material consisting of glass contg. alumina and a back layer formed of a crystalline glass material consisting of low melting glass and high melting crystalline glass. CONSTITUTION:This double layer crystallized glass material is formed by fusing and integrating the front layer and the back layer consisting of the crystalline glass material formed by fusing of the low melting glass powder and the high melting crystalline glass. The above-mentioned front layer is formed by the low melting glass powder, high melting glass powder and alumina powder which are fused and crystallized after the softening and fusing of the low melting glass. The above-mentioned low melting glass powder has the essential components consisting, by weight %, of 65 to 80% SiO2, 5 to 15% CaO, 10 to 30% Na2O+K2O, <=10% MgO, and <=10% Al2O3.

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.

(Prior Art) In recent years, crystallized glass materials, which have a slightly different texture from natural stone and glass materials, are being used in many fields as interior and exterior materials.

Regarding a preferred method for producing the crystallized glass material, Japanese Patent Application No. 6
As disclosed in No. 1-291203, an organic binder (e.g., polyvinyl alcohol) is added and mixed to a mixed powder consisting of a low softening point glass powder and a high softening point glass powder, and then this is used for thick plate forming. The glass powder is placed in a mold and pressure-molded at room temperature (room-temperature pressure molding), and the resulting glass powder compact is heat-treated to promote densification and crystallization.
There is a method of applying crystallization heat treatment). In this case, before the crystallization heat treatment, the binder is removed by heat treatment at 300 to 400° C. for several tens of hours. On the other hand, without using an organic binder, the mixed powder is put into a mold and densified at a temperature above the softening point of the low-softening point glass powder and below the softening point of the high-softening point glass powder, and then press-molded ( There is a method in which the glass powder compact is subjected to crystallization heat treatment to the obtained glass powder compact.

According to this method, since the low softening point glass powder acts as a binder, there is no need to add an organic binder, and in the process of densification of the glass powder, the air that exists between the powders becomes unsoftened and highly softened. It has the advantage that it is easily discharged to the outside along the surface of particles such as glass powder, and an extremely dense crystallized glass material with almost no bubbles or pores can be easily obtained.

(Problems to be Solved by the Invention) The crystallized glass material produced by the above-mentioned pressure molding method is dense, has good gloss when polished, and has excellent quality as an interior/exterior building material. Furthermore, there is an advantage that large size materials of about 1 m x 1 m can be easily manufactured. If a non-standard size material is required, the standard size material is appropriately cut using a high-speed cutter at the time of shipping or installation.

However, as shown in FIG.
There is a problem in that when cutting 1 at high speed, local defects 23 tend to occur along the cutting direction from the lower surface where the cutting rotary teeth 22 come off. The distance between the lower surface and the outer periphery of the rotary teeth 22 is small, and it is thought that cracks are likely to occur, and the cracks propagate and lead to breakage.

Note that a synthetic resin film is usually applied to the back side of the crystallized glass material in order to prevent the fragments from scattering in the event of breakage, but even if such a film is formed, the defects cannot be prevented.

The present invention was made in view of such problems, and an object of the present invention is to provide a crystallized glass material that does not cause local defects on the cut end surface even when cut at high speed.

(Means for Solving the Problems) The crystallized glass material of the present invention, which has been made to achieve the above object, is characterized in that a low softening point glass powder, a high softening point glass powder, and an alumina powder soften the low softening point glass powder. A surface layer formed of a crystallized glass material formed by fusion and crystallization after fusion, and a crystalline glass material formed by fusion and crystallization of a low softening point glass powder and a high softening point crystalline glass powder. The structure of the invention is that the formed back layer is fused and integrated.

At this time, the main component of the low softening point glass powder is 5iOz in weight%: 65 to 80% CaO:
5-15% NazO + KzO: 10-30% MgO
: 10% or less Az, o, : 10% or less, and the main component of the high softening point glass powder is 5t (h:
65-80%, AlzOx: 25% or less Na
zO+KzO: 5 to 15%, and the main component of the high softening point crystalline glass powder is 5i (h
: 25~55% Alt(h: 5~2
It is preferable to use one containing 0% CaO: 25 to 65%.

(Function) The crystallized glass material in the surface layer is a product in which low softening point glass powder, high softening point glass powder, and alumina powder are fused and crystallized after softening and fusing of the low softening point glass powder. When low softening point glass powders are softened and fused together, air existing between the glass powders is discharged to the outside of the glass powder along the particle surfaces of the unsoftened high softening point glass powder or alumina powder. Therefore, it is difficult for air bubbles to remain in the fused product of both glass powders, and as a result, air bubbles and pores are eliminated as much as possible in the crystallized glass material of the present invention.

The low softening point glass powder particularly exemplified in the present invention has the composition of ordinary soda lime glass, while the high softening point glass powder has a SiO□ content in the same range as the low softening point glass powder. , from a low softening point glass powder that is softened and fused even at a temperature above the softening point of the low softening point glass powder and below the crystallization initiation temperature of the same powder, to an unsoftened high softening point glass powder, a wire modification such as Na resin is performed. Ion diffusion transfer is likely to occur.

As a result, the softening temperature decreases in the component diffusion region of the high softening point glass powder, and the softened and fused low softening point glass powder and high softening point glass powder are easily fused and integrated.

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

0 Low softening point glass powder Sing: 65 to 80% If it is less than 65%, crystals are difficult to precipitate, while if it exceeds 80%, the softening point becomes high and high temperature heating is required in heat treatment, which is not preferable in terms of manufacturing.

CaO: 5-1O% If it is less than 5%, the softening point will be high, while if it exceeds 10%, crystals will be difficult to precipitate.

NazO+K2O: 10-30% If it is less than 10%, the softening point will be high, while if it exceeds 30%, crystals will be difficult to precipitate.

MgO: 10% or less If it exceeds 10%, crystals will be difficult to precipitate. Note that when the content is 2% or more, crystal growth is slowed down and densification by sufficient softening and fusion is facilitated.

Aj! z03: 10% or less A j! Since the softening point of 203 increases as the content increases, it is preferable to keep it at 10% or less.

0 high softening point glass powder 5rOt: 65-80% If it is less than 65%, it is difficult for Sin and crystals to precipitate, while at 80%
If it exceeds this, the softening point becomes too high and diffusion of components with the low softening point glass powder becomes difficult.

AI! , □03: 25% or less AI! , 203 has the effect of raising the glass softening point, but if it exceeds 25%, it becomes difficult for 5in2 crystals to precipitate.

Na, 0 + K2O: 5 to 15% If it is less than 5%, the softening point becomes too high and diffusion of the components with the low softening point glass powder becomes difficult.

On the other hand, if it exceeds 15%, the softening point becomes too low, and there is a possibility that the softening temperature becomes 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 glass powders are as described above, and the inclusion of other appropriate glass components is permitted within a range that does not deteriorate the physical properties, but in order to maintain appropriate physical properties, the main components must be It is preferable that the total is 90% or more.

Alumina powder used with high softening point glass powder is
At the powder grain boundaries, components diffuse and fuse with the softened low softening point glass powder, resulting in crystallization (mainly Naz
O・A 12 zO+ ・2SiOz crystallization) can be strongly bonded, and the coefficient of linear expansion is more than 10% lower than that of low softening point glass powder. Compressive stress can be left in the glass-ceramic material, and the glass-ceramic material can be strengthened. Furthermore, since the coefficient of thermal expansion of the crystallized glass material itself can be lowered, it has excellent thermal shock resistance.

Next, the effect of the crystalline glass material forming the back layer will be explained. The crystalline glass material has a large amount of crystals,
It is a material with only a small amount of amorphous glass,
The crystal part acts to prevent the crank from progressing. It is thought that the crank that occurs in the crystallized glass material occurs in the amorphous glass portion and propagates within the same portion. Therefore, by coating the back surface, which is the starting point for cracks, with a crystalline glass material, it is possible to effectively prevent the occurrence of cracks, their subsequent propagation, and the formation of defects.

The crystalline glass material is obtained by fusing and crystallizing the low softening point glass powder and the high softening point crystalline glass powder. In particular, the high softening point crystalline glass powder illustrated is easy to fuse with the low softening point glass powder, and crystals (mainly CaO・SiO□ products and 2CaO−Aj!zO
+・5ift product) is precipitated in large quantities, and the reason for limiting the components is shown below.

The unit is weight %.

0 High softening point crystalline glass powder Sin: 25-55% If it is less than 25%, it will crystallize early, so if only the low softening point glass powder is softened, a significant decrease in strength will occur due to insufficient densification of the product, and the back layer will no longer be able to fulfill its role as 5
If it exceeds 5%, the amount of crystals decreases, resulting in insufficient strength and hardness.

Aj2□0. : 5 to 20% If it is less than 5%, the crystallization rate becomes too high and the densification of the product tends to be insufficient. On the other hand, if it exceeds 20%, it becomes difficult to precipitate crystals uniformly.

CaO: 25-65% 25% to ensure the amount of crystals to obtain strength and hardness
Although the above is necessary, if it exceeds 65%, the crystallization rate becomes too high, resulting in a significant decrease in strength due to insufficient densification of the product.

The main components of the high softening point crystalline glass powder are as described above, and the inclusion of other appropriate glass components is permitted within the range that does not deteriorate the physical properties.However, in order to maintain appropriate physical properties, the sum of the main components must be is preferably 90% or more.

(Example) Fig. 1 shows a cross-sectional view of a multilayer crystallized glass material according to the present invention, in which a surface layer 1 formed of a dense, glossy, and high-strength crystallized glass material, and a chip-resistant A backing layer 2 made of a crystalline glass material with excellent properties is fused and integrated. still,
As described above, a synthetic resin film for scattering prevention is formed on the lower surface of the backing layer 2, if necessary.

The main components of the suitable low softening point glass powder and high softening point glass powder for forming the crystallized glass material of the surface layer 1 are as described above, and the latter has a glass softening point of about 800°C. It is desirable to adjust the ingredients so that the above is achieved. Low softening point glass powder has the composition of ordinary soda lime glass, and has a softening point of 600-750'C2
This is because the crystallization start temperature is about 800°C or lower.

Glass powder can be obtained by melting glass of the desired composition, crushing it with water, and then crushing it, but soda lime glass cullet can be used as a raw material for low softening point glass powder ( In addition, as for the high softening point glass powder, crushed pearlite (pearlite) can be used.Pearlite contains more than ten percent of AffizOi and has a softening point of about 900°C or higher, It is supplied in large quantities to the market as aggregate, etc., and is easy to obtain.
Excellent economy.

Regarding the particle size of low softening point glass powder, high softening point glass powder, and alumina powder, the smaller the particle size and the larger the amount, the easier the softening and fusion of low softening point glass powder and high softening point glass powder and alumina powder. This facilitates fusion with the glass powder molded body, which in turn promotes densification and crystallization of the glass powder compact.

For this reason, it is desirable that the particle size of the glass powder is such that 80% or more (preferably 90% or more) of the glass powder has a particle size of 200 mesh or less. Note that the finer the alumina powder is, the better it is because the coarser the particle size, the worse the luster. However, the finer the particle size, the higher the price, so it is usually 0.5 to 20 μm.
m is used.

It is desirable that the blending ratio of the low softening point glass powder in the surface layer mixed powder of the low softening point glass powder, high softening point glass powder, and alumina powder is 20 to 90% by weight. If it is less than 20%, it results in insufficient softening and fusion with high softening point glass powder, etc., and insufficient densification of the glass powder compact. Furthermore, the amount of crystals is insufficient, resulting in a decrease in strength. On the other hand, 9
If it exceeds 0%, the shape retention of the glass powder molded body during heat treatment will be insufficient, and the effect of discharging air bubbles in the molded body will be insufficient. Since the alumina powder deteriorates the gloss of the crystallized glass material, it is preferable to limit the amount to 10% by weight or less based on the total amount of the mixed powder. However, in order to obtain an effective reinforcing effect due to compressive residual stress, it is desirable to add 1% by weight or more.

A colored crystallized glass material can be produced by using a mixed powder obtained by adding and mixing a metal oxide coloring agent (usually a fine powder of 200 mesh or less) to the mixed powder. The colorant is added within a range that does not reduce the physical properties (particularly strength) required of the crystallized glass material, and an example of the amount added is shown below. The amount added is based on the added mixed powder, and the unit is weight %.

CrzO, , CuO, Mn0z -1% or less CoO
...3% or less FeO, Fe=On, FE! z03...to% or less The same low softening point glass powder as that for the surface layer 1 is used to form the crystalline glass material of the back layer 2 of the multilayer crystallized glass material. On the other hand, high softening point crystalline glass powder can be obtained by melting glass having the composition described above, pulverizing it, and crushing it.

The particle size of the high softening point crystalline glass powder does not have to be as fine as the above-mentioned high softening point glass powder. The larger the amount of crystalline glass powder blended and the larger the particle size, the greater the amount of micropores in the crystalline glass material. There is no particular reason why pores should be removed. still,
Crystalline glass materials also have no pores, and the denser they are, the higher their strength, so if the backing layer 2 is to not only prevent the occurrence and propagation of cracks, but also function as a strength member, use fine grains. do it.

Regarding the blending ratio of low softening point glass powder and high softening point crystalline glass powder, if a large amount of low softening point glass powder is present, a considerable amount of amorphous glass portion will remain, and the chipping prevention effect will be lost. Therefore, the high softening point crystalline glass powder is 2 times the total amount of the mixed powder for the back layer with the low softening point glass powder.
It is preferable to mix it in an amount of about 0 to 70% by weight. If it is less than 20%, the amount of crystals will be insufficient, while if it exceeds 70%, there will be a significant lack of strength due to insufficient densification.

A thickness of about 1 mm is sufficient for preventing the occurrence and propagation of cracks, but in consideration of ease of manufacture, the thickness of the back layer 2 is preferably about 3 to 5 mm.

Note that the back layer 2 may be provided up to about 95% of the total thickness of the multilayer material. However, if the back layer is to be made thicker, it is necessary to use a high-strength, dense material that is at least as strong as the surface layer material as the back layer material.

In addition, the surface layer 1 and MN2 are integrally pressure-formed and crystallized as described later, and are unified by fusion and crystallization, but if the coefficients of thermal expansion of both layers 1.2 are significantly different, the boundary The difference in coefficient of thermal expansion is
It is preferable to keep it within the range of h and c. The coefficient of thermal expansion can be adjusted, for example, by adjusting the amount of alumina powder not added in the surface layer material.

In order to produce the multi-layer crystallized glass material of the present invention, after preparing the above-described mixed powder for the surface layer and the back layer,
As shown in the figure, one of the mixed powders (usually the mixed powder for the surface layer) 11 is scattered and filled into a molding die 13, and after the other mixed powder 12 is spread and charged thereon, the upper mold 14 is It is manufactured by fitting, cold-pressure molding or hot-pressure molding, and then subjecting it to crystallization heat treatment. Pressure is 100 to 200 kgf/cffl for room temperature pressure molding.
degree, 3 to 50 kgf/cffl in hot pressure forming
It is enough. Moreover, when performing hot pressing, the densification temperature is usually 600 to 800°C. Crystallization heat treatment is performed by heating the glass powder compact at 800 to 950°C for 3 to 3
This is done by holding for 0 Hr. In crystallization heat treatment, high softening point glass powder and high softening point crystalline glass powder are in an unsoftened state and serve as aggregates, so even if a glass powder compact is heat treated alone, deformation may occur. There's no fear. In addition, when carrying out cold-pressure molding, adding an organic binder to the mixed powder and performing binder removal treatment before crystallization heat treatment are as described above.

Next, specific examples will be described.

(1) Various powders having the compositions (wt%) shown in Table 1 were prepared. The average particle size of the powder of G, P, and W materials is 13μ
m (97% powder of 200 mesh or less), material A was 1°8 μl. Note that current was used as a raw material for the low softening point glass powder (G material), and pearlite was used as the raw material for the high softening point glass powder (P material).

Next Table 1 Table 2 (Note) Material G...Solution point glass powder P material...High softening point glass powder A material...Alumina powder W material...Arm Q Soiling point Strength glass powder (2) Prepare the mixed powder for the surface layer and the back layer according to the formulation shown in Table 2, and according to the hot pressing conditions shown in the same table, 900 x 90
A double-layer glass powder molded body having a thickness of 0 mm and a total thickness of 20 mm (back layer 3 to 5) was manufactured. For comparison, glass powder compacts with only the surface layer material or only the back layer material were also produced at the same time. Comparative Example 1 has the same dimensions as the Example, Comparative Examples 2 and 3 have 3
00 x 300 nn x thickness 20 mm.

(3) After hot pressing, the glass powder compact was taken out of the molding die, inserted into a heating furnace maintained at 600"C and soaked, and then heated to 900°C in both Examples and Comparative Examples. After holding for 4 hours to achieve crystallization, the mixture was slowly cooled.

(4) The bending strength, water absorption rate, and thermal expansion coefficient at 50 to 500°C of the obtained plate-shaped crystallized glass material were investigated.

In addition, the bending strength was determined by applying a load to the examples from the surface layer side. The thickness of the test piece was 15 mm, and in the example Table N
The thickness of the back layer was 12 mm and the thickness of the back layer was 3 mm. A cutting test was also conducted. The rotating tooth used was a diamond abrasive metal bond disc grindstone with a diameter of 360 mm, and the cutting conditions were a rotation speed of 174.
ORPM and feed rate were set to 0° and 75 m/min. The results of these measurements and tests are shown in Table 3. Note that the water absorption rate is a measure of the porosity. The defect incidence rate is measured by considering cranks with a diameter of 5 mm or more as defects.

Table 3 (5) From Table 3, it is clear from Comparative Examples 2 and 3 that the crystalline glass material forming the back layer of the present invention has a large amount of crystals, so it has high bending strength and is excellent in chipping prevention effect. I understand that. Further, the multilayer crystallized glass materials of Examples 1 and 2 in which this crystalline glass material was formed as the back layer had a remarkable reduction in the defect occurrence rate compared to the single layer Comparative Examples 1 and 4.

(Effects of the Invention) As explained above, the multi-layer crystallized glass material of the present invention has a surface layer made of a dense and glossy crystallized glass material, and a back layer containing low and high softening point glass powder. Since the back layer formed of the crystalline glass material is fused and integrated with the softening point crystalline glass powder and crystallized, the large amount of crystals present in the back layer prevents the occurrence and development of cranks. This effectively prevents damage to the cut surface due to the progress of the crank.

In addition, the surface layer uses low-softening point and high-softening point glass powder of a specific composition that is inexpensive, easy to obtain, and easy to fuse, and is further added with alumina powder to promote crystallization with the glass powder. This strengthens the bond and allows compressive stress to remain in the crystallized glass material, making it possible to significantly improve the strength and thermal shock resistance.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional view of the multilayer glass-ceramic material of the present invention, Fig. 2 is a cross-sectional view of a molding die showing the molding state of the multi-layer glass powder compact, and Fig. 3 is a partial cross-sectional view of the multilayer glass-ceramic material of the present invention. A partial sectional view showing a cut state is shown. 1...surface layer, 2...back layer.

Claims (2)

[Claims] (1) A surface layer formed of a crystallized glass material in which a low softening point glass powder, a high softening point glass powder, and an alumina powder are fused and crystallized after softening and fusion of the low softening point glass powder; A multi-layer crystallized glass material characterized by a back layer formed of a crystalline glass material formed by fusing and crystallizing point glass powder and high softening point crystalline glass powder. . (2) The main component of low softening point glass powder is SiO_
2: 65-80% CaO: 5-15% Na_2O+K_
2O: 10-30% MgO: 10% or less Al_2O_3
The main components of the high softening point glass powder are SiO_2: 65 to 80%, Al_2O_3: 25% or less, Na_2O + K_2O: 5 to 15%, and the high softening point crystalline glass powder has the following main components: is in weight% SiO_2: 25-55% Al_2O_3: 5-20%
The multilayer crystallized glass material according to claim 1, characterized in that the CaO content is 25 to 65%.