JPS5888141A - Manufacture of leadless silver-colored roofing tile having no interpenetration and discoloration - Google Patents

Abstract

PURPOSE:To obtain the titled leadless silver-colored roofing tile, by using leadless glaze composed mainly of a manganese compound, and containing increased amount of SiO2-Al2O3 and the necessary minimum amount of alkali component. CONSTITUTION:The objective roofing tile can be manufactured by using a leadless glaze containing (in terms of Seger scale) (i) <=0.025mol of Li2O, K2O and Na2O in total as R2O component, (ii) 0.15-0.25mol of CaO, <=0.1mol of SrO, BaO, ZnO, and/or MgO, and >=0.6mol of MnO as RO component, (iii) >=0.1mol of Al2O3 as neutral component, and (iv) >=1.2mol of SiO2 and 0.1-0.2mol of B2O3 as acidic component, wherein the molar ratio of SiO2/Al2O3 is 35-3. About 90-100g of the above glaze is applied to one dried roofing tile body, and baked in an oxidizing atmosphere at 1,030-1,130 deg.C using a tunnel kiln to obtain the objective silver-colored roofing tile.

Description

Detailed Description of the Invention Conventionally, silver Japanese tiles have been produced in large quantities in tunnel kilns by oxidation firing at or before 1080 degrees Celsius, but due to discoloration and the occurrence of intrusions due to changes over time, the intrusions are being piled up in the open. There were major drawbacks such as dust getting inside.

In addition, the six products that have been researched to eliminate this drawback still use lead compounds in the glaze, which means that they are still not completely safe from an occupational health standpoint. Currently, there is a demand for lead-free silver tiles that do not discolor or penetrate.

In terms of glaze composition, lead-free glazes such as Seegel and leaded glazes have been used in the past, but with this composition, Ll
, 0, K, O, Na, o (1) The number is as large as seven,
Due to the small number of moles of 810□ and *jIIO, penetration is likely to occur as described below, and furthermore, the latter composition has compositional disadvantages such as unavoidable discoloration because it contains ouo f. .

As a result of intensive research, we succeeded in improving the above drawbacks.

That is, the present invention aims to prevent discoloration and penetration of the above-mentioned silver tiles by using a lead-free glaze, and supplements the previously filed invention.

The method basically involves keeping the alkaline component in the glaze to the necessary minimum, and not including lead compounds.
- At the same time as increasing the content of Al2O,.

4, which mainly uses a manganese compound as the metal compound. As a result, the coefficient of thermal expansion of the glaze is reduced, the conventional purchasing is suppressed, and discoloration over time is prevented, and at the same time, the glaze is made lead-free, which is a feature of the present invention.

More specifically, it is well known that when a metal compound is added to the glaze until it is saturated, it becomes a metal-like matte axis, and this principle is also applied to traditional silver roof tiles.

However, research has shown that glazes containing tetra-copper compounds among metal compounds have reduced acid resistance due to the elution of copper ore depending on the firing conditions, and are unavoidable in discoloration over time.

Therefore, in the present invention, the copper compound in the 1lII drug is suppressed as much as possible, and the main component is manganese compound.
It contained 0.6 mole or more of O. moreover.

F @ @ 03, NiO%Coo%WO,,MOO
, V, O, etc. or 221 or more metal compounds in a total amount of 0.01 to 0.1 mol, the silver color becomes even stronger.

In terms of penetration, alkali metal compounds (t, i, u,
"l' s 120) is 0.025 mol or less in Segel representation, pbo is not included in the RO acid component, 0.15 to 0.25 mol of OaO component is included, and 8rO% J1aO, MgO.

Containing 0.1 mol or less of one or more of ZnO-based RO acid components, Al, 03.810. 0.
Contains 1 mol, 1.2 mol or more, B2O5 from 0.1 to
The inclusion of 0.2 mol is necessary to bring the thermal expansion of the glaze closer to that of the tile base, to prevent penetration, and to make the glaze lead-free.

That is, alkali metal compounds such as Na2O, It is large and has a negative effect on penetration.

From this, the research results N a 20, K2O, Ll
, 0 to a total amount of 0.025 moles was found to be a major factor.

As mentioned above, the reason why Pk)O was not included in the RO acid component was necessary in order to make the entire glaze lead-free and to ensure a safe working environment and occupational health.

Further, B, 03 component is 0.1 to 0.2 mol, oBo component is 0.15 mol to 0.25 mol, 1Ir
One or two RO acid components such as o, ZnO, MgO1BaO, etc.
Containing more than 0.1 mole in total is as follows:
This is necessary to ensure that the glaze melts smoothly and is safe from penetration.

That is, these components include Ll, 0, R such as Na-1X-
, O component, and pbo component, but the factors that affect thermal expansion are Ll, 0, Nano
, is not as large as KzO, and it has been found that it is safe against penetration if used within the above molar number range.

The fact that 1.2 mol of 810 dew and 0.1 mol or more of An, O, and more are required also means that heat l! This has been clarified through research from the perspective of books, and 8io, , AIL
,O.

When the number of moles of AA1105 was small, the silver color immediately after firing was good and the appearance was excellent in sharpness, but as a result of observation over time, the occurrence of penetration was unavoidable.

In this way, it has been found that penetration cannot be sufficiently prevented even if either one of the two O mole numbers is less than this. Also, 1110. / Al, 05 component molar ratio of 35 to 3 is also derived from the above-mentioned penetration prevention aspect, and 5io2 / h12o, O ratio in this range causes the so-called eutectic phenomenon, - This is necessary in order to reduce the number of moles of components that serve as solvents in drugs and to reduce the coefficient of thermal expansion.

From the above, as an example of the method of obtaining a non-discolored, non-penetrating, lead-free silver tile according to the present invention, lead-free frit 10-20 parts wollastonite 0-8 silica sand 10-25 kaolin 15-50 manganese dioxide 25-35 Add 0.5 parts of bentonite and 5 parts of OMOQ to a mixture of zircon silicate 6-15 and rutile ore 6-15, grind it in a wet ball mill, and apply it to a dry tile base with 90 parts per tile.
Glazed to a coating weight of ~100g at 1030℃~11
By oxidizing and firing in a tunnel kiln at 30°C using the conventional method, silver tiles that are resistant to discoloration and penetration can be produced.

Next, the present invention will be explained in more detail with reference to actual examples.

EXAMPLE Using the raw materials of colemanite, boric acid, lime, and barium carbonate silica sand, a powdery mixture as shown in Zegel expression was mixed uniformly, melted at 1300 to 1350°C, and quenched to obtain a lead-free frit.

Next, a glaze mixture according to the Zegel display was created using this lead-free frit, silica sand aluminum hydroxide, rum, zircon silicate, rutile ore, and manganese dioxide, and to this, 5 parts of OMOQ and 0.5 parts of bentonite were added. The resulting glaze slip was applied to a dry tile base, applied to a coating weight of 95 g, and oxidized and fired in a tunnel kiln at a maximum of 1085°C for 27 hours to obtain a good silver tile. This tile was immersed in 1N hydrochloric acid and the glazed surface was observed, and no discoloration was observed. In addition, no penetration or discoloration was observed in a treatment test conducted in an autoclave at 5 atm for 1 hour.

Agent Asamura Hao 4 other people

Claims (1)

[Claims] In the glaze Ot''-gel representation, the R, O components include Li, O. .15 to 0.25 mol,
8rO. One or more of BaO1ZfiO and MgO is 0
．． Contains 1 mol or less, and contains 0.6 mol or more of MnO,
Furthermore, 0.1 mole or more of AjL,05 as a neutral component, 1.2 mole or more of an acidic component Toshiteaio, and B,03
Contains 0.1 to 0.2 mol, and 810s/AAII
A method for manufacturing silver Japanese roof tiles, which uses a lead-free glaze with an O30 molar ratio of 35 to 3, and is oxidized and fired at 1030°C to 1130°C in a tunnel glaze.