JP2000128671A - Glazed ceramic and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a large-sized and thin-walled glazed ceramic with excellent cutting processability. SOLUTION: This glazed ceramic is such one as to be provided with a crackle-bearing glaze layer on the surface thereof, consisting of a talc-based sintered compact >=20 wt.% in talc remains; wherein the crackle density on the glaze surface is such as to be 20-500 in the number of points afforded by crossing a line segment 10 cm long with the crackles, and the crackles are filled by coating the glaze layer with a silicone resin or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glazed ceramic and a method for producing the same, and in particular, the glaze has an intrusion,
The present invention relates to a glazed ceramic excellent in cutting workability and a method for producing the same.

[0002]

2. Description of the Related Art Fine cracks appearing on the glaze layer on the surface of ceramics such as ceramics are called intrusions. Some pottery such as teacups have this intrusion. JP-A-51-131509 describes that a silicone coating layer is formed on the surface of a porcelain having intrusion in order to prevent tea astringents and the like from entering the intrusion to cause contamination. . II. As a method for producing a porcelain plate or tile using talc as a raw material, Japanese Patent Publication No.
What is described in 36543 etc. is publicly known. In this conventional method, after forming a talc-containing raw material, 1100
Fired at a temperature of ℃ or more.

[0003]

When glazed ceramics are cut, large chipping is likely to occur in the glaze layer on the surface, and large long cracks are likely to occur in the glaze layer.

[0004] Further, conventional talc-based porcelain plates and tiles are fired at a high temperature and therefore have high hardness and are difficult to cut.

Further, the conventional glazed porcelain plate has a disadvantage that hydration expansion is large and it is difficult to increase the size. That is, the ceramic plate-like body expands due to the hydration reaction, but in the case of a glazed ceramic plate, the glaze layer on the surface does not absorb water and does not expand. Therefore, when the glazed porcelain plate hydrates, concave warpage gradually occurs. Further, tensile stress is generated in the glaze layer as the ceramic plate expands, and cracks are generated in the glaze layer. For this reason, the conventional thickness of 5
In the case of ６6 mm, a large glazed porcelain plate of 300 mm × 300 mm or more that does not cause the problem of concave warpage is hardly realized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a glazed ceramic in which cracks do not or hardly spread in the glaze layer at the time of cutting, and a method for producing the same.

Another object of the present invention is to provide a glazed ceramic which can be easily cut and a method for producing the same.

Another object of the present invention is to provide a large-sized and thinned glazed ceramic and a method for producing the same.

[0009]

The glazed ceramic of the present invention is a glazed ceramic provided with a glaze layer having an intrusion on the surface of the ceramic, wherein a line segment having a length of 10 cm intersects the intrusion on the surface of the glaze. The number of points is 20 to 500, and the penetration density is characterized.

In such glazed ceramics, since fine penetration is formed in the glaze layer, large chipping occurs in the glaze layer at the time of cutting, or a long and large crack is newly generated in the glaze layer. Almost no.
For this reason, it is possible to obtain a cut processed body having an excellent surface aesthetics and a well-cut surface.

In the glazed ceramic of the present invention, since the glaze layer has fine penetration, when a tensile stress is applied to the glaze layer, the crack width of the penetration increases,
The entire glaze layer expands following this tensile stress. For this reason, even if the glazed ceramics absorbs water, it does not warp and there is no long and large crack in the glaze layer.

The ceramic is preferably an easily-cuttable ceramic, and as the easily-cuttable ceramic, a ceramic containing talc as a main raw material is particularly preferable. In this ceramic, the residual amount of talc after firing is 20% by weight.
, The cutting workability is extremely good.

By applying a synthetic resin to the surface of the glaze of the glazed ceramics, the penetration of dirt into the intrusion can be prevented.

The method for producing a glazed ceramic according to the present invention comprises:
Using the prepared raw material and the glaze raw material prepared so that the difference between the linear thermal expansion coefficient of the base sintered body and the linear thermal expansion coefficient of the glaze layer becomes 18 × 10 ⁻⁶ or more, this mixed raw material is molded, Then, it is characterized by firing after glazing, or firing the blended raw material after molding, then glazing and firing.

By sintering the ceramic substrate having such a difference in linear thermal expansion coefficient and the glaze, fine penetration is formed in the glaze layer.

As a raw material for preparing this ceramic, one containing 40 to 80 parts by weight of talc is preferable. In this case, by setting the firing temperature to 900 to 1000 ° C,
20% by weight or more of talc remains in the ceramic body,
Ceramics can be easily cut.

Further, in the present invention, by applying a synthetic resin to the glaze layer formed by baking, it is possible to make the glaze less likely to adhere.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In order to produce the glazed ceramic of the present invention, it is preferable to use a raw material mixture containing talc. Particularly preferred raw material preparations include 40 to 80 parts by weight of talc, 20 to 50 parts by weight of an aggregate component, and 5 to 20 parts by weight of clay (100 parts by weight in total). If the amount of talc is less than 40 parts by weight, the cutability of the sintered body becomes insufficient. Since talc has good pulverizability, if it is more than 80 parts by weight, the amount of fine particles increases, and the moldability deteriorates.

As the above-mentioned aggregate component, feldspar, pyroxene,
One or more of pottery stone, silica stone, chamotte and the like are preferable. This aggregate component is added as a filler for increasing the volume of the ceramic sintered body. In addition, since it is hard to be crushed, there is an effect that coarse particles remain even after crushing, and the moldability is improved. This aggregate component is 900-100
It hardly melts at a firing temperature of 0 ° C. This aggregate component is 2
If the amount is less than 0 parts by weight, the moldability deteriorates. Also, 50
When the amount is more than the weight part, the strength of the molded body and the sintered body decreases.

Clay is added to enhance plasticity during molding. If the amount of the clay is less than 5 parts by weight, the plasticity is insufficient, and if it is more than 20 parts by weight, the moldability deteriorates. As the clay, kaolin clay such as Kibushi clay and Frogme clay, benite and the like can be used.

[0021] One or more of calcium carbonate, magnesium carbonate and lithium carbonate, strontium carbonate and barium carbonate may be added to the raw material in an amount of 10 parts by weight or less. These have the effect of reducing the hydration expansion of the sintered body by preventing the dehydration of talc or clay from vitrifying and promoting crystallization.

The glazed ceramics of the present invention can be obtained by pulverizing / mixing the raw materials having the above mixing ratio, molding, glazing and firing, or firing after molding, glazing and firing. Can be

As this molding method, various methods such as press molding, slurry casting molding, and extrusion molding can be adopted. During this molding, methyl cellulose or the like is added as necessary.

In the case of firing after forming, after drying if necessary, firing is carried out preferably at 900 to 1000 ° C, more preferably at 900 to 950 ° C. Firing temperature is 900 ℃
If it is lower than this, sintering of talc is insufficient, and the strength of the sintered body decreases. If the firing temperature is higher than 1000 ° C., the sintering amount of talc becomes excessive, and the cutting workability of the sintered body is reduced.

900-1000 ° C., especially 900-950
In the case of the sintering temperature of ° C., talc is appropriately melted, the strength of the sintered body becomes a satisfactory strength, the residual amount of talc becomes 20% by weight or more, and the cutability of the sintered body is good. . If the amount of residual talc is excessive, the strength of the sintered body is reduced.
Preferably it is 5% by weight.

The residual amount of talc can be quantified using X-ray diffraction. Specifically, calcium fluoride was used as an internal standard substance, glass was used as a diluent, and the d values were 1.5570, 1.52 with an X-ray diffractometer.
It is determined by the average value of the strength of the surface of 70.

The linear thermal expansion coefficient of the thus obtained sintered compact is about 6.5 to 7.5 × 10 ⁻⁶ ° C. ⁻¹ .

After glazing the sintered body or the molded body,
Bake. Various methods such as curtain hanging, spray hanging and centrifugal hanging can be adopted as the glaze method.

The glaze baking temperature is 800 ° C to 1000 ° C, especially 9
00-950 degreeC is preferable. The glaze temperature is 1000 ℃
If it is more than that, the residual talc sinters, and the cutability of the fired body becomes poor. If the temperature is lower than 800 ° C., it is difficult to produce a glaze that melts. When firing after glazing without firing the molded body, the firing temperature is 900 to 1000 ° C., particularly 9 ° C., for the same reason as in the case of firing the molded body.
The temperature is preferably set to 00 to 950 ° C.

In the case where firing is performed twice, ie, firing after forming and firing after glazing, it is better to set the firing temperature after glazing higher than the firing temperature after shaping to obtain a smooth glaze layer surface. Is obtained, which is preferable. This is because if the glaze firing temperature after glazing is higher than the firing temperature after molding, the base component reacts and volatilizes during glaze firing after glazing, thereby disturbing the glaze layer surface.

The glaze preferably has a coefficient of linear thermal expansion of 23 × 10 ⁻⁶ ° C.- ¹ or more after baking the glaze, and boric acid frit glaze, lead frit glaze, or the like can be used.

When the difference in linear thermal expansion coefficient between this glaze and the ceramic fired body is 18 × 10 ⁻⁶ or more, particularly 23 × 10 ⁻⁶ or more and C ⁻¹ , penetration can be sufficiently generated. In particular, after the above glaze firing, the temperature is reduced to 400 ° C or less.
Cooling in about 0 to 20 minutes allows sufficient penetration to occur.

The thickness of the glaze layer after baking is 20 to
It is preferable to glaze to a thickness of 200 μm, especially 30 to 100 μm. If the glaze layer is thicker than 200 μm, the shrinkage of the glaze layer after baking the glaze becomes excessive, and the glazed ceramics are likely to be concavely warped. On the other hand, the glaze layer is 2
If the thickness is less than 0 μm, the improvement of the appearance by the glaze becomes insufficient.

In the present invention, the amount of penetration is quantified by the number of points where an arbitrary line segment having a length of 10 cm of the glaze layer crosses the penetration. For example, length 10c on the surface of glazed ceramics
This number is obtained by drawing an arbitrary line segment of m and counting the number of points where this line segment intersects with the penetration.
When the glazed ceramics are small with a side of 10 cm or less, the number of points may be counted by drawing a line segment of 5 cm, for example, and the number may be doubled.

In the present invention, the number of points is 20 to 50.
0, preferably 50 to 500. The number of points is 2
If it is less than 0, the cutting processability is low, and if it is more than 500, the gloss of the glaze layer is low.

The intrusion consists of a crack having a very small width, and the width is preferably about 0.1 to 0.002 μm.

The density of the intrusion has a large relationship with the weight of the glaze. Even if the same base material is glazed with the same glaze, the density of the intrusion changes depending on the weight of the glaze. Generally, as the weight of the glaze increases, the thickness of the glaze layer increases, and the density of the glaze increases.Therefore, a wide penetration of the crack layer occurs at a coarse density. Narrow intrusion occurs at a fine density.

The glazed ceramic is made of a synthetic resin such as a silicone resin, an acrylic resin, or a fluororesin in an amount of 1 to 15
It can be applied at a rate of about 0 g / m ² by spraying, curtaining, sponge coating, brush coating, or the like, and the intrusion can be filled with a synthetic resin to make it less likely to be stained.

[0039]

Example 1 Raw materials having the following mixing ratio (total of 100 parts by weight) were wet-pulverized, dried, granulated, and dry-molded to obtain a molded body having a size of 200 × 200 mm. After firing for 5 hours, a ceramic sintered body was obtained.

55 parts by weight of talc 30 parts by weight of feldspar 15 parts by weight of clay (kibushi-based clay) This sintered body was glazed with a boric acid frit glaze of 0.03 g / cm ² by a spraying method, and 900 ° C. × 30 hours. Glazed. 20 g / m ² of acrylic modified silicone resin
To obtain a glazed ceramic product. The thickness of the glaze layer after firing is 100 μm.

Table 1 shows the penetration amount of the glazed ceramic and the residual amount of talc. In addition, the linear thermal expansion coefficients of the ceramic sintered body and the glaze layer were measured. As for the glaze layer, the glaze slurry was dried to form a powder (water content: 4%).
After forming the rod into a rod at a pressure of 50 kgf / cm ² , the rod was hardened with silica sand and baked at the same temperature as the glaze for 50 minutes, and then the surrounding silica sand was removed. Was measured. The results are shown in Table 1. Further, the cutting workability of this glazed ceramic is set to an outer diameter of 125.
mm, blade thickness 1.8mm, super-teeth tip saw 86 teeth are rotated at 6000 revolutions per minute, cut by applying 1kgf force in horizontal direction for 5 seconds, and the cut length per second is measured. The results are shown in Table 1. The glazed ceramic was attached with ink and dried, and then wiped off with a cloth soaked with water to examine the ease of penetration. Table 1 shows the results.

Examples 2 to 5 and Comparative Examples 1 and 2 Glazed ceramics were produced in the same manner except that the raw material preparation was changed as shown in Table 1 and the thickness of the glaze layer was changed as shown in Table 1, and the same measurements and evaluations were made. Was done. Table 1 shows the results. In Examples 4 and 5, a fluorosilicone resin was used as the resin. In Comparative Example 1, the firing of the compact was performed for 1
Performed at 200 ° C.

[0043]

[Table 1]

The following is clear from Table 1.

Comparative Example 1 is a normal tile using talc as a main raw material. Since it is fired at 1200 ° C., the sintering and melting of the base material sufficiently proceed, and the cutting workability is poor. . In Comparative Example 2, since the low thermal expansion glaze was used, there was no penetration of the glaze surface, but since it had a continuous glaze surface, the cutting workability was lower than in Examples 1 and 2.
Although not shown in the table, the concave warp after hydration expansion of the base material was large.

On the other hand, in Examples 1 to 5, good cutting workability was obtained. In Example 2, the same base material as that of Example 1 was used and a glaze having a low coefficient of linear thermal expansion was used, and the penetration amount was smaller than that of Example 1. In Example 3, the amount of talc remaining was small because the amount of talc blended in the base material was small. For this reason, the cutting workability is lower than in Example 1. In Example 4, although the base material preparation was changed, the coefficient of linear thermal expansion of the base material was high, and the glaze used had a small thermal expansion. However, since the thickness of the glaze layer was small, the penetration amount was large. ing. In Example 5, the amount of talc remaining was increased because the amount of talc was increased. For this reason, the cutting workability of the base is improved.

[0047]

As is clear from the above Examples and Comparative Examples, according to the present invention, there is provided a glazed ceramic which is excellent in cutting workability and hardly adheres dirt.

Claims (9)

[Claims] 1. A glazed ceramic provided with a glaze layer having an intrusion on the surface of the ceramic, wherein the number of points at which a line segment having a length of 10 cm intersects the intrusion is 20 to 500 on the surface of the glaze. Glazed ceramics characterized by the following. 2. The glazed ceramic according to claim 1, wherein the ceramic is an easily cut ceramic. 3. The glazed ceramic according to claim 1, wherein the ceramic is a ceramic using a talc raw material. 4. The glazed ceramic according to claim 3, wherein the amount of residual talc in the ceramic is 20% by weight or more. 5. A glazed ceramic according to any one of claims 1 to 3, wherein a synthetic resin is applied to the glaze layer. 6. The method for producing a glazed ceramic according to claim 1, wherein a difference between a linear thermal expansion coefficient of the base sintered body and a linear thermal expansion coefficient of the glaze layer is 18 × 10 ⁻⁶ / ° C. or more. A method for producing glazed ceramics, comprising: using the prepared raw material and the glaze raw material, shaping the prepared raw material, followed by glazing and firing. 7. The method for producing a glazed ceramic according to claim 6, wherein the mixed raw material is molded, fired, then glazed and fired. 8. The method according to claim 6, wherein the raw material contains 40 to 80 parts by weight of talc, and the calcination temperature is 9%.
A method for producing a glazed ceramic, which is performed at a temperature of from 00 to 1000 ° C. 9. The method for producing glazed ceramics according to claim 6, wherein after glazing and firing, a synthetic resin is applied to the glaze layer.