JPH09227153A - Lead-free glazing for ceramics and production of ceramics - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lead-free glazing for ceramics, absolutely free from harmful lead, exhibiting improved penetration resistance and corrosion resistance and having roughened surface to prevent the slippage and increase the safety of tile roofing work and to provide a process for producing ceramics. SOLUTION: This glazing has a composition of (in terms of Segel unit) (0.03-0.13) R2 O, (1.4-2.5) SiO2 , (0.25-0.61) RO, (0.19-0.53) Al2 O3 , (0.09-0.23) ZrO2 . (0.38-0.59) MnO, (0.01-0.15) Fe2 O3 and (0.15-0.34) RO2 wherein R2 O is Na2 O and/or K2 O, RO is CaO and/or MgO and RO2 is one or more substances selected from TiO2 , SnO2 , P2 O5 and V2 O5 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-free glaze for ceramics and a method for manufacturing ceramics.

[0002]

2. Description of the Related Art Conventional silver glaze roof tiles contain PbO, MnO and Cu0 as the main components of the glaze. This is PbO
By this, the melting point of the glaze is lowered, and MnO is crystallized to prevent penetration. However, since PbO and MnO are contained, lead vapor and manganese vapor evaporate in the firing kiln during use, which damages the firing kiln and shortens the service life. There is a problem that the color development is adversely affected. In addition, lead vapor is harmful, and if it leaks to the outside, there are problems with the work environment and pollution, and it is necessary to take sufficient measures for wastewater treatment.

Further, since the conventional roof tile contains lead, it cannot be roughened and a non-slip roof tile cannot be manufactured by firing. This is done by crushing the raw material with a pot mill etc. to make the particle size fine, but if the particle size is coarse, lead with large specific gravity tends to precipitate, which causes color unevenness, so it is necessary to miniaturize the raw material containing lead. was there.

[0004]

In view of the above problems, the present invention does not contain harmful lead at all, increases resistance to penetration, improves corrosion resistance, and roughens the surface to allow slippage. (EN) Provided is a glaze for a lead-free ceramic and a method for manufacturing the ceramic, which is difficult to improve the safety of roofing work.

[0005]

The glaze for lead-free ceramics according to claim 1 of the present invention is (0.03-0.13) R ₂ O (1.4-2.5) SiO ₂ (0.25-0.61) RO (0.19- 0.53) Al ₂ O ₃ (0.09 to 0.23) ZrO ₂ (0.38 to 0.59) MnO (0.01 to 0.15) Fe ₂ O ₃ (0.15 to 0.34) RO ₂ However, R ₂ O is either Na ₂ O or K ₂ O. 1 or 2
Represents a species, and RO is any one of CaO and MgO or 2
Represents a species, RO ₂ is TiO ₂ , SnO ₂ , P ₂ O ₅ , V
It is characterized by having a composition that represents one or more of ₂ O ₅ .

The lead-free ceramic glaze according to claim 2 is
The particle size distribution of the glaze is characterized by 24 to 40% by weight of particles having a particle size of 32 μm or more.

Further, the manufacturing method of the ceramics according to claim 3 is,
In the Zegel display, (0.03 to 0.13) R ₂ O (1.4 to 2.5) SiO ₂ (0.25 to 0.61) RO (0.19 to 0.53) Al ₂ O ₃ (0.09 to 0.23) ZrO ₂ (0.38 to 0.59) MnO (0.01 to 0.15) ) Fe ₂ O ₃ (0.15 to 0.34) RO _{2 where} R ₂ O is either Na ₂ O or K ₂ O or 2
Represents a species, and RO is any one of CaO and MgO or 2
Represents a species, RO ₂ is TiO ₂ , SnO ₂ , P ₂ O ₅ , V
It is characterized in that a glaze having a composition representing any one or two or more of ₂ O ₅ is glazed on a base material of a ceramic product and is oxidized and baked at 1050 to 1200 ° C.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail. Whereas conventional glazes are mainly PbO, MnO, Cu0 and, features of the present invention, suppressing the content of Mn as well as lead-free, contrary SiO ₂ and Z
By increasing the amount of rO ₂ added, it was possible to obtain a lead-free ceramic glaze having characteristics superior to conventional ones.

Explaining the components of the glaze of the present invention,
R ₂ O of the basic component of Zegel is Na ₂ O, K ₂ O
Of any one of or two, and the molar ratio is 0.03 to 0.
The range is 13. These Na ₂ O and K ₂ O have the function of lowering the melting point of the glaze instead of PbO, and the above range was derived from the result of experiments that the firing temperature was adjusted to 1050 to 1200 ° C. .

The basic component RO represents one or two of CaO and MgO, and its molar ratio is 0.25 to 0.61.
Range. Both CaO and MgO have the effect of lowering the melting point, and in particular MgO also has the effect of promoting the crystallization of Zr and Mn. If it is less than 0.25 mol, the effect of lowering the melting point is small, and if it is added in excess of 0.61 mol, the effect is small.

Further, MnO, which is a basic component, has a function of crystallizing and a function of producing a roof tile color because it is black. The molar ratio is preferably 0.38 to 0.59, and the addition amount is set smaller than in the past. If it is less than 0.38 mol, the effect is small, and if it is added in excess of 0.59 mol, gas may be generated and the firing kiln may be damaged.

The neutral component Al ₂ O ₃ has a function of preventing penetration and a function of emulsifying, and its molar ratio is preferably in the range of 0.19 to 0.53. If it is less than 0.19 mol, the penetration preventing effect is small, and if it exceeds 0.53 mol, the effect is small. Further, the neutral component Fe ₂ O ₃ has a function of crystallizing, and its molar ratio is preferably in the range of 0.01 to 0.15. In this case, if it is less than 0.01 mol, the crystallization effect is small, and if it is added in excess of 0.15 mol, the effect is small.

The acidic component SiO ₂ has a function of adjusting the melting point and a function of preventing penetration. The molar ratio is preferably 1.4 to 2.5, particularly 1.5 to 2.
3 is desirable, and the addition amount is set higher than in the past.
If it is less than 1.4 mol, the effect is small, and if it is added in excess of 2.5 mol, the set firing temperature is 1050 to 1200.
This is because it becomes difficult to adjust the temperature to ° C.

ZrO _{2, which} is an acidic component, functions to crystallize and increase the surface hardness, as well as to prevent penetration and emulsification, and the molar ratio thereof is preferably 0.09 to 0.23. If it is less than 0.09 mol, the hardness improving effect is small,
The effect does not change even if a large amount is added in excess of the molar amount.

Further, RO _{2 which} is an acidic component is TiO ₂ , Sn
It represents one or more of O ₂ , P ₂ O ₅ , and V ₂ O ₅ , which promotes crystallization of Mn and has the effect of lowering the melting point, and its molar ratio is preferably 0.15 to 0.34.

The glaze of the present invention comprises Cr ₂ O ₃ and NiO.
Various color tones can be adjusted by substituting pigments such as ₂ , Fe ₂ O ₃ , CoO, MgO, CuO, and Sn.

Further, the glaze of the present invention can roughen the surface while preventing color change by adjusting the raw material particle size. For example, when mixing with a wet mixer and the particle size distribution is in the range of 24-40% by weight of particles with a particle size of 32 μm or more, the surface roughness of roof tiles fired by glaze with this glaze is 50 μm or more, and the roof is Even if you walk on the tiles with the tabi or tabi in the roofing work, you can work safely without slipping. If the particle size of 32 μm or more is less than 24% by weight, the roof tile has a surface roughness of less than 50 μm and the anti-slip effect is deteriorated, and if it exceeds 40% by weight, peeling easily occurs. Therefore, the glaze of the present invention does not contain lead of heavy specific gravity, so even if the raw material of the glaze is coarse-grained, the raw material of heavy specific gravity is uniformly dispersed without settling, and as a result, it is possible to prevent color change, and thus by firing. It has become possible to roughen the surface.

[0018]

【Example】

Example 1 An example of the present invention will be described below. A glaze for smoldering silver roof tiles composed of the compositions of samples No. 1 to No. 4 shown in Table 1 in the Zegel display was prepared, and 60 g of water content weight was applied to the surface of the base material of the roof tile, and the glaze was applied to Table 2.
Oxidation firing was performed at the firing temperature shown in. The color development and color unevenness of the fired gantry were observed, a corrosion resistance test was conducted, and the results are shown in Table 2. It should be noted that the corrosion resistance test is performed with a strong acid solution of pH 2 24
After being immersed for a period of time, it was naturally dried, allowed to stand for 6 days, then again immersed in a strong acid solution for 24 hours, this was repeated 4 times, and then the surface change state was observed.

[0019]

[Table 1]

[0020]

[Table 2]

Example 2 A glaze raw material having the composition shown in No. 1 in Table 1 was mixed and pulverized by a wet mixer, and the particle size distribution was 36% by weight when the particle size was less than 12 μm, and the particle size was 12 μm or more.
A glaze having a particle size of less than 32 μm of 33% by weight and a particle size of 32 μm or more of 31% by weight was prepared, and the surface of the base material of the roof tile was glazed with a water content weight of 60 g per sheet and oxidatively baked at 1120 ° C. The roughness of the surface of the fired gantry was measured at 5 points with a three-dimensional surface roughness meter, and the average value is shown in No. 5 of Table 3. The surface condition was observed and the same corrosion resistance test as in Example 1 was performed. It was

For comparison, a glaze raw material having the same composition was mixed and pulverized by a wet pot mill so that the particle size distribution was 12
Prepare a glaze of 43% by weight less than μm, 43% by weight of particle size 12 μm or more and less than 32 μm, 14% by weight of particle size 32 μm or more, and apply 60 g of this to the surface of the unglazed base of the roof tile. Oxidation and firing at 1120 ° C. The roughness of the surface of the fired sash was measured in the same manner and the average value thereof was shown. The surface condition was observed and a corrosion resistance test was also conducted. The results are shown in Table 3.

[0023]

[Table 3]

From the results shown in Table 3, the surface roughness of the conventional glossy roof tile is about 25 to 30 μm, but in the present invention, even if it is formed on a rough surface of 50 μm or more that does not slip even when walking with a tabi tabi. ,
It was confirmed that there was no effect on color unevenness or corrosion resistance. In the above explanation, the glaze for roof tiles was shown as ceramics,
It can be widely used for ceramics such as tableware, vases, flower pots, and figurines.

[0025]

As described above, according to the method for producing a glaze for a lead-free ceramic and a ceramic according to the present invention, since it does not contain harmful lead at all, there is no problem in pollution such as smoke emission or waste water treatment, and firing is possible. Little damage to the kiln. Further, resistance to penetration is increased, corrosion resistance is improved, and the surface can be roughened to prevent slipping, and the safety of roofing work can be improved.

Claims (3)

[Claims] 1. Zegel display (0.03 to 0.13) R ₂ O (1.4 to 2.5) SiO ₂ (0.25 to 0.61) RO (0.19 to 0.53) Al ₂ O ₃ (0.09 to 0.23) ZrO ₂ (0.38 to 0.59) MnO (0.01 to 0.15) Fe ₂ O ₃ (0.15 to 0.34) RO _{2 where} R ₂ O is either Na ₂ O or K ₂ O or 2
Represents a species, and RO is any one of CaO and MgO or 2
Represents a species, RO ₂ is TiO ₂ , SnO ₂ , P ₂ O ₅ , V
_A glaze for lead-free ceramics, characterized in that it has a composition that represents one or more of ₂ O ₅ . 2. The glaze for lead-free ceramics according to claim 1, wherein the particle size distribution of the glaze is 24 to 40% by weight of particles having a particle size of 32 μm or more. 3. In the Zegel display, (0.03 to 0.13) R ₂ O (1.4 to 2.5) SiO ₂ (0.25 to 0.61) RO (0.19 to 0.53) Al ₂ O ₃ (0.09 to 0.23) ZrO ₂ (0.38 to 0.59) MnO (0.01 to 0.15) Fe ₂ O ₃ (0.15 to 0.34) RO _{2 where} R ₂ O is either Na ₂ O or K ₂ O or 2
Represents a species, and RO is any one of CaO and MgO or 2
Represents a species, RO ₂ is TiO ₂ , SnO ₂ , P ₂ O ₅ , V
_A method for producing a ceramic product, which comprises glazeing a base material of a ceramic product with a glaze having a composition that represents one or more of ₂ O ₅ and oxidizing and firing at 1050 to 1200 ° C.