JPH0667773B2 - Glaze for tiles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a glaze for tiles, and more particularly to a glaze for tiles used for so-called once baking, which produces an interior tile by only one baking.

[Prior Art] Conventionally, an interior tile is manufactured by a so-called double firing, which is a process of firing twice. That is, in the conventional interior tile, after the kneaded clay is formed and dried, the first firing (baking) is performed.
After cooling and cooling, glazed on this unglazed tile, the second
It is manufactured by performing the second firing.

One of the reasons for baking twice is that the interior tiles are glazed thicker than the exterior tiles (that is, a large amount of glaze is applied to increase the thickness of the glaze) and the glazed surface is rich in luster. Is required to be formed.

That is, if the interior tiles are to be baked once to be glazed thickly, a large amount of water will be leached from the glaze to the kneaded clay body side. However, if the water contained in the glaze is absorbed into the kneaded clay compact in an excessive amount, the kneaded clay compact is swollen and deformed. Further, since the kneaded clay molded body has a small water absorption amount, even if a large amount of mud glaze is hung on the molded body, the clay does not flow down, and the glaze solid content (glaze, graz
The required amount of e) cannot be left on the surface of the molded body. In this case, if the water content of the glaze is reduced, the amount of absorbed water to the kneaded clay compact will be reduced even if it is thickly glazed, the swelling of the compact will be suppressed to a certain extent, and the amount of solid glaze remaining on the surface of the compact will be reduced. However, the conventional glazes having a low water content and a high specific gravity also have a high viscosity at the same time, which makes it extremely difficult to uniformly glaze the entire surface of the molded body.

In the case of firing twice, since the kneaded clay molded body is glazed after being made into a unglazed product, swelling or deformation does not occur in the unglazed product even if the conventional mud glaze is glazed thickly. . Further, since the water content in the mud glaze is quickly absorbed, the glaze solid content can be thickened and can be evenly adhered to the surface of the unglazed product.

[Problems to be Solved by the Invention] As described above, when the conventional mud glaze is used as a glaze for producing interior tiles by the baking method, the kneaded clay swells and deforms. Unfortunately, it was not possible to produce beautiful interior tiles. Further, the glaze also flowed down from the molded body, and it was not possible to form a uniform glaze layer.

[Means for Solving the Problems] The present invention provides a glaze for tiles that enables the interior tiles to be manufactured by baking once.

The tile glaze of the present invention is a slurry-like tile glaze containing a frit, in which 100 parts by weight of the following components (inclusive) and 0 to 100 parts by weight of this component are included.
˜15 parts by weight of pigment, specific gravity of 1.7 to 2.0 and viscosity at 25 ° C. of 5 to 100 cp (centimeter
Poise).

SiO ₂ 55 to 65 wt% _Al 2 _O 3 10 to 18 wt% CaO 18 to 25 oxide weight percent alkali metal 0.5-4% by weight _ZrO 2 0 wt% _B 2 _O 3 0 to 2 wt% One or more of MgO, BaO, SrO, and ZnO Frit containing 0 to 10 wt% in total: 50 to 80 parts by weight Feldspar: 10 to 25 parts by weight Clay: 0.5 to 10 parts by weight Zircon: 0 to 20 parts by weight Quartz sand: 0 to 10 parts by weight Alumina: 0 to 5 parts by weight Titanium oxide: 0 to 10 parts by weight Barium carbonate: 0 to 10 parts by weight Zinc oxide: 0 to 5 parts by weight [Action] For the tile of the present invention The glaze has a specific gravity of 1.7 to 2.0.
Since the solid content concentration is large and the amount of absorbed water to the kneaded clay compact is small even when thickly glazed,
The kneaded clay compact does not swell and deform, and the residual amount of the glaze solid content on the surface of the compact is large, and a large amount of glaze can be applied at one time. Moreover, since the tile glaze of the present invention has a relatively low viscosity of 5 to 100 cp, it can be easily glazed to a uniform thickness.

Hereinafter, the effect of the characteristics of the glaze of the present invention will be described in detail together with its preferred embodiments.

The specific gravity of the glaze for tiles of the present invention is 1.7 to 2.0.
When the specific gravity of the glaze is 1.7 or more, the water content of the glaze is reduced, and excessive water is absorbed by the kneaded clay compact, which prevents the compact from swelling and deforming. Further, when a large amount of mud glaze is applied to the molded body, a required amount of the glaze solid content can be left on the surface of the molded body, which enables thick coating.
If the specific gravity of the glaze is less than 1.7, the water content in the glaze becomes excessive, resulting in the above swelling and deformation, and thickening cannot be performed. On the other hand, when the specific gravity of the glaze exceeds 2.0, the amount of water in the glaze is insufficient, the uneven absorption rate of the kneaded clay compact cannot be sufficiently compensated, and it becomes difficult to apply the thickness smoothly. . Therefore,
In the present invention, the specific gravity of the glaze is 1.7 to 2.0.

The viscosity of the tile glaze of the present invention is 5 to 100 cp. If the viscosity exceeds 100 cp, the viscosity is too high to obtain a uniform and smooth glazed surface. On the other hand, if the viscosity is less than 5 cp, it is difficult to satisfy the preferable range of high specific gravity as described above. Therefore, in the present invention,
The specific gravity of the glaze is 5 to 100 cp. A particularly preferred viscosity of the glaze is 10-40 cp.

Such a glaze of the present invention is prepared by dispersing a frit having an appropriate composition, other feldspar, clay, zircon (zirconium silicate), etc., in water, alcohol, or another appropriate liquid so as to have the above composition. In that case, it can be easily obtained by adjusting the specific gravity and the viscosity using an appropriate dispersant. In this case, as the dispersant, those commercially available as a glaze dispersant such as a carboxylic acid dispersant, a phosphoric acid dispersant and a humic acid dispersant can be used. Examples of commercially available dispersants include an aqueous solution of a special polycarboxylic acid type polymer (manufactured by KE-512 Gao Chemical Co., Ltd.) and the like.

As a method of glazeing the kneaded clay compact with the glaze of the present invention, a curtaining method is suitable. In this curtaining method, a water film (curtain) of mud glaze is formed in a direction intersecting the conveying direction of a conveyer that continuously conveys the kneaded clay body, and the kneaded clay body is formed under the water film. The glazed layer is thickly formed on the upper surface of the molded body by passing through the mold. In order to form the above-mentioned water film, an outflow box having a slit-shaped opening extending in a direction intersecting the transportation direction on the bottom surface is installed on the upper side of the conveyor surface, and the mud glaze has a constant level in this outflow box. Will be supplied.

By the way, there is the following reason as the reason for performing the double baking in the conventional manufacturing of the interior tile. That is, as described above, the interior tile needs to be glazed thicker than the exterior tile, but if the clay body (green compact) is glazed thickly for once baking, the firing process It becomes difficult for the gas generated from the kneaded clay to pass through the glaze layer, breaks through the glazed layer in the semi-molten or molten state, and crater-like gas ejection holes and bubbles, pinholes, and bubble blowing phenomena such as cracks in the glaze layer. The situation will be called.

That is, in the process of firing the kneaded clay body (base), gas is generated along with the thermal decomposition of the carbonate minerals contained in the kneaded clay and the combustion of the organic substance. This gas generation is completed at about 700 to 800 ° C. when the temperature rises extremely slowly, but the rate of temperature rise is high under the high production efficiency manufacturing method employing a roller hearth kiln, etc. The gas evolution reaction is delayed and slips into the region where the ambient temperature exceeds 1000 ° C. In particular, since the temperature rise inside the molded body is delayed as compared with the surface of the molded body, the gas generating reaction may even continue even when the ambient temperature reaches 1100 ° C.

In the conventional glaze for tiles, it begins to soften rapidly at around 1000 ° C and becomes a molten state to cover the surface of the tile substrate, but even after the melted glaze covers the surface in this way. As described above, when gas is generated from the inside of the base material, the above-mentioned bubble blowing phenomenon occurs.

According to the double firing method, the base material is unglazed and
During the second firing, no gas is generated from the base material, the bubble blowing phenomenon does not occur even if it is thickly glazed, and an interior tile having a beautiful flat glaze surface with rich gloss is manufactured.

As described above, if an attempt is made to manufacture an interior tile using a conventional glaze by a baking method, a bubble blowing phenomenon occurs, and the glaze surface is not suitable for a product. For this reason as well, conventionally, the interior tiles have to be fired twice, resulting in a high fuel cost for firing, increased labor for firing, and low productivity.

In the present invention, as a glaze that prevents such a bubble blowing phenomenon and enables a good thickening by baking once,
As a whole, 100 parts by weight of a component including the following components and 0 to 15 parts by weight of a pigment are used based on 100 parts by weight of the component.

SiO ₂ 55 to 65 wt% _Al 2 _O 3 10 to 18 wt% CaO 18 to 25 oxide weight percent alkali metal 0.5-4% by weight _ZrO 2 0 wt% _B 2 _O 3 0 to 2 wt% One or more of MgO, Ba0, SrO, and ZnO 0 to 10% by weight in total Frit: 50 to 80 parts by weight Pebble: 10 to 25 parts by weight Clay: 0.5 to 10 parts by weight Zircon: 0 20 parts by weight Quartz sand: 0 to 10 parts by weight Alumina: 0 to 5 parts by weight Titanium oxide: 0 to 10 parts by weight Barium carbonate: 0 to 10 parts by weight Zinc oxide: 0 to 5 parts by weight Included in the tile glaze having the above composition. The frit has a small amount of alkali metal oxides and B ₂ O ₃ components, and its viscosity decreases slowly even when heated to a temperature higher than the softening start point, and the frit does not have to reach a temperature considerably higher than the softening start temperature. The whole In specific, not to cover the so-called Beta'. The same applies to components other than the frit. Therefore, even if gas is generated from the inside of the base material, the gas can pass through between the frit particles and easily escape to the outside, and the bubble blowing phenomenon is prevented.

Hereinafter, the action of each component of the glaze of the above composition will be described in detail together with its preferred embodiments.

First, the frit component will be described.

In the above frit, SiO ₂ and Al ₂ O ₃ are the main components that constitute the high softening point frit and constitute the skeleton portion of the aluminosilicate glass.

In addition, CaO and an oxide of an alkali metal (hereinafter, abbreviated as R ₂ O) each have a function of partially cutting off the aluminosilicate network, promoting vitrification thereof, and lowering the softening start temperature.

The chemical composition of the frit is SiO ₂
Is 55 to 65% by weight (hereinafter abbreviated to%) and Al ₂ O ₃ is 10
~ 18%, CaO is 18~25%, _{R 2} O is 0.5 to 4
%, And the softening temperature of the frit becomes excessively low to cause a bubble blowing phenomenon, and on the contrary, the softening temperature becomes excessively high and the glaze is not sufficiently melted even after firing of the base material. Occurs. Particularly preferable ranges are 57 to 62.0% for SiO _{2 and} 12 to 12 for Al ₂ O _3.
16%, CaO is 19 to 21%, and R ₂ O is 1 to 3%. Li ₂ O may be omitted, but it is preferable to add it in order to obtain the smoothness of the glaze surface similar to double firing. This Li
The content% of ₂ O is preferably in the range of 0.5 to 1.5%.
If it is less than 0.5%, the effect of improving smoothness is small, and it is 1.5%.
If it exceeds, pinholes are likely to appear on the glaze surface.

The frit may include B ₂ O ₃ , MgO, ZnO, SrO, and BaO. By including these oxides as needed, the softening point of the frit can be lowered. These oxides, too many drops frit softening point excessively to contain, and because so reduce the viscosity of the frit quickly after initial softening, B ₂
O ₃ is 2% or less, especially 1% or less, MgO is 5% or less, especially 3% or less, ZnO is 5% or less, especially 3% or less,
It is preferable that SrO is 5% or less, especially 3% or less, and BaO is 5% or less, especially 3% or less. In addition, MgO,
Even if the total amount of BaO, SrO, and ZnO is 10% or less.

The frit of the present invention is made of ZrO ₂ which gives the hiding power of the substrate.
May be contained by 10% or less.

The above frit may further contain other compounds such as BaO and other oxides, chlorides and sulfates, if necessary.
The total amount of them is preferably 3% or less, more preferably 1% or less.

The above frit can be produced by a conventional method by preparing and melting a usual frit raw material, cooling it, and then pulverizing it.

The above-mentioned feldspar and clay each have an action of increasing the melting point of the glaze. In order to obtain a suitable melting point of the glaze, feldspar is used in an amount of 10 to 25 parts by weight, particularly 12 to 18 parts by weight, and clay such as kaolin and frog eyes is set to 0.5 to 10 parts by weight, preferably 1 to 3 parts by weight.

Zircon (zirconium silicate) is a component that imparts hiding power, and its amount is 0 to 20 parts by weight, preferably 10 to 15 parts by weight.

Silica sand, alumina, titanium oxide, barium carbonate,
Zinc oxide is a component that adjusts the melting point of glaze and adjusts bright matte.
Silica sand 0 to 10 parts by weight, alumina 0 to 5 parts by weight, titanium oxide 0 to 10 parts by weight, barium carbonate 0 to 10 parts by weight, and zinc oxide 0 to 5 parts by weight.

The pigment is blended as necessary for the purpose of improving the designability of the glazed surface of the tile. Any pigment can be used as long as it is a pigment used for tiles, and its content is 100 parts by weight based on 100 parts by weight of the above components.
The amount is 0 to 15 parts by weight.

[Examples] Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples.

In addition, in the following Examples and Comparative Examples, the following was used as a kneaded clay molded body for tiles.

45 parts by weight of wax, 40 parts by weight of clay, 10 limestone
Parts by weight and 5 parts by weight of chamotte are crushed and mixed by a ball mill, water is added, and the mixture is molded at 350 kg / cm ² and fitted. The size of this green body is 10
It is cm × 10 cm × 0.5 cm.

Further, a roller hearth kiln having a total length of 25 m was used for firing this molded body, a running speed was 1.0 m / min, and a firing zone maximum temperature was 1190 ° C.

Examples 1 to 8 and Comparative Examples 1 to 4 Feldspar, silica stone, and limestone are adopted as raw materials, and these are dried, crushed, sieved, and then compounded, and the temperature is 1400 ° C. in a crucible.
It was melted for 1 hour at room temperature and then rapidly cooled, and the frit No. having the chemical composition shown in Table 1 was used. 1-3 were prepared.

Using this frit, mix with feldspar, clay, zircon, etc. in a ball mill in the composition shown in Table 2, add water and a carboxylic acid dispersant in the amounts shown in Table 2, and further mix in a ball mill. A glaze having the specific gravity and viscosity shown in Table 2 was used. This mud glaze was applied to the surface of the molded body by a curtaining method so that the thickness after drying would be about 0.6 mm,
After drying, it was baked.

When the tiles were observed after firing, it was found that all of the tiles of Examples 1 to 8 were flat interior tiles having no glaze and were flat and glossy, and had a thick glaze layer. Admitted.

On the other hand, among Comparative Examples 1 to 4, bubbles of Comparative Examples 1 to 3 were blown during firing, and those of Comparative Example 4 were insufficient in gloss, and it was confirmed that once baked, they could not be used practically. It was

[Effect] As is clear from the above Examples and Comparative Examples, by using the tile glaze of the present invention, a tile having a beautiful thick glaze layer is produced by baking once. Therefore, by adopting the glaze for tiles of the present invention, the manufacturing cost of the interior tiles is significantly reduced.

Claims (1)

[Claims] 1. A sludge-like glaze for tiles containing a frit, which contains 100 parts by weight of the following components as a whole and 0 to 15 parts by weight of a pigment per 100 parts by weight of this component, and has a specific gravity of 1.7 to 2.0 and 25 ° C
A glaze for tiles having a viscosity of 5 to 100 cp. SiO ₂ 55 to 65 wt% _Al 2 _O 3 10 to 18 wt% CaO 18 to 25 oxide weight percent alkali metal 0.5-4% by weight _ZrO 2 0 wt% _B 2 _O 3 0 to 2 wt% One or two or more of MgO, BaO, SrO, and ZnO Frit containing 0 to 10 wt% in total: 50 to 80 parts by weight Feldspar: 10 to 25 parts by weight Clay: 0.5 to 10 parts by weight Zircon: 0 20 parts by weight Silica sand: 0 to 10 parts by weight Alumina: 0 to 5 parts by weight Titanium oxide: 0 to 10 parts by weight Barium carbonate: 0 to 10 parts by weight Zinc oxide: 0 to 5 parts by weight