JPS6354030B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coating agent for improving the surface condition of clay roof tiles, particularly water absorption and water permeability. It is natural for roofing materials to prevent water from seeping through to the back of the roof tiles, but in reality, there are complaints that water can seep through to the back of the roof tiles, rotting the wood, and causing leaks. is asked a lot. In order to improve the water permeability of such tiles, clay tiles are made by thoroughly crushing, kneading, and vacuum degassing the clay used as the base material, and then baking at the firing temperature and firing time that are optimal for the clay. Significant improvements can be made by combining these two factors, but this alone will not be sufficient to achieve the objective. This is because water permeation through the tiles is due to the pores penetrating the base, and no matter how optimal firing or sintering conditions are selected, it is impossible to wipe out the pores penetrating the base. Therefore, the present inventor investigated the relationship between water absorption and water permeability for commercially available clay tiles using an absorption/permeability tester as shown in the drawing, and found that tiles that are difficult to see through water stains have a significantly slow water absorption rate. found. Naturally, such tiles also have extremely low water permeability. The measurement method using the absorption/water permeability tester was as follows. The volume of water per unit length in the glass capillary tube 1, which is graduated in mm, is measured in advance (ml/mm). In the case of a water permeability test, sample 2, which has been subjected to normal water absorption based on the water permeability test of JIS A5208, is wrapped in a plastic bag with holes equal to the inner diameter of the cylinder and then placed on a support stand 3, and a rubber packing 4, a rubber stopper 9, and a glass are placed on top of it. Place the capillary tube 1 and the cylinder 5 with the two-way screws C ₁ and C ₂ and tighten the screws 6 firmly. Open the two-way cylinders C ₁ and C ₂ and pour water from the tank 7 into the cylinder through _the rubber tube 8,
Close C ₂ when the water line reaches the top. The water level further rises in the glass capillary tube 1 and closes C ₁ at around 0 on the scale. As time passes, the water level in the glass capillary decreases. In other words, the length of the drop in the water level is the water permeability. Water permeability rate = (water permeation amount) / (inner area of cylinder) x (water permeation time) (ml/cm ² h) Water permeability = (water permeation amount) / (sample weight) x 100 (%) Based on these facts. As a result of various studies on the production of tiles with extremely low permeability and water absorption rate, we were able to achieve the objective by applying a thin layer of glaze with a specific composition to the tile base, and completed the present invention. I came to the point. The gist of the present invention is "a coating agent for improving the water absorption and water permeability of clay tiles" which is mainly made of low expansion glass and contains Al ₂ O ₃ , B ₂ O ₃ and SiO ₂ as essential components. It is in. That is, the present invention has (1) an oxide composition of Na ₂ O,
2-10% of one or more of K ₂ O, Li ₂ O, CaO,
One or more of MgO, BaO, ZnO, SrO 0
~8%, _Al2O3 5 _~ 15 _% , _B2O3 5~20%, _SiO2 50
A coating agent for improving water absorption and water permeability for clay roof tiles characterized by ~78%. (2) The oxide composition is one or more of Na ₂ O, K ₂ O, and Li ₂ O2
~7%, including PbO, PbO and CaO, MgO, BaO,
The total amount of one or more of ZnO and SrO is 2 or more
30%, _{Al2O3 2} ~ ₁₀ %, _B2O3 5~15%, _SiO2 50~
A coating agent used on clay tiles to improve water absorption and water permeability, characterized by a content of 78%. (3) Oxide composition is one or more of Na ₂ O, K ₂ O, Li ₂ O 0.5
~5%, one or more of CaO, MgO, BaO, ZnO, SrO 0.5-5%, Al ₂ O ₃ 20-45%, B ₂ O ₃ 1
The present invention relates to three coating agents for improving water absorption and water permeability for clay roof tiles, characterized by containing ~8% SiO2 and 45~60% _SiO2 . The application of the coating agent of the present invention is as follows: For ceramic glazed tiles, the coating agent is pulverized and mixed using a wet method to adjust the concentration, and then applied to one or both sides of the clay tile base, and then glazed and dried and fired. Ibushi tiles are coated on one or both sides of the clay tile base, then dried, fired,
Make a smoldering fire. For example, the first or second of the present invention with adjusted concentration.
After applying the second coating agent thinly to the clay tile base,
Glazed with regular glaze and heated in a furnace with an oxidizing atmosphere.
After firing at 950 to 1250℃, or after applying a thin layer of the first, second, or third coating agent with an adjusted concentration to the clay tile base, it is fired in a furnace in an oxidizing atmosphere.
An improved clay tile can be obtained by firing at 950-1250℃ and then smoking in a reducing atmosphere at 800-900℃. In the present invention, the oxide composition of the coating agent for improving water absorption and water permeability is limited as described above for the following reasons. That is, the water absorption and water permeability of tiles are due to the countless pores that penetrate through the tile base and are present in the base of the tile. Therefore, water absorption and water permeation should be significantly reduced by blocking the pores that penetrate the substrate or by preventing water from entering the pores that penetrate the substrate, but this is extremely difficult and difficult to achieve good results. Few. In order to close the pores penetrating the base material during firing, it is necessary for the coating agent to maintain an appropriate viscosity during firing and maintain an expansion coefficient close to that of the base material. For this purpose, as a result of experiments with coating agents of various compositions, it was found that the firing temperature of the clay tile base and the product differs depending on the production area, and the first invention mainly
The object is oxidized tiles that are fired at 1050℃, the second invention is mainly for glazed tiles that are fired at a temperature range of 950 to 1050℃, and the third invention is mainly for oxidized tiles that are fired at 1050 to 1250℃. This applies to glazed roof tiles. (1) The reason for the composition limitation of the first invention will be described below.
One or more types of Na ₂ O, K ₂ O, Li ₂ O 2 ~
10wt% is less than 2%, 950 to 1050℃
This is because an effective glassy film for reducing water absorption and water permeability is not formed in the temperature range of 10
%, the expansion of the vitreous film formed becomes too large, causing cracks in the film, making it impossible to reduce the water absorption and water permeability of the tile. If the total content of one or more of CaO, MgO, BaO, ZnO, and SrO exceeds 8%, the expansion of the substrate and the expansion of the glassy coating to improve water absorption and water permeability may not match. Firing at 1050℃ becomes difficult. The reason why B ₂ O ₃ is set at 5 to 20% is because if it is less than 5%, a glassy film will not be formed in the firing temperature range and it will not be an effective film, and if it exceeds 20%, the corrosion resistance of the glassy film will be significantly reduced. This is because as the film temperature decreases, the reaction with the substrate becomes significant, making it difficult to form an effective film. The reason for setting Al ₂ O ₃ to 5 to 15% is that if it is less than 5%, the corrosion resistance and durability of the formed film will be insufficient, and if it exceeds 15%, the glass will not be effective in the firing temperature range of 950 to 1050℃. This is because a solid film cannot be formed. The reason for setting SiO ₂ to 50 to 78% is
This is because if it is less than 50%, it is difficult to form a glassy film with corrosion resistance, and if it exceeds 78%, it becomes impossible to form a glassy film that is effective in the firing temperature range. (2) The reason for the composition limitation of the second invention will be described below.
The total amount of PbO and divalent alkaline earth metal is 2 to 30
%, and the introduction of PbO into the divalent alkaline earth metal forms a glassy film that is effective in improving water absorption and water permeability in the temperature range of 1050 to 950°C, and is compatible with glazes. If the total amount is less than 2%, it is impossible to form an effective film, and if it exceeds 30%, the corrosion resistance of the film will be significantly reduced. The reason for setting the total amount of monovalent alkali components to 2 to 7% is the same as the reason for limiting the alkali components in the first invention,
The reason why the Al ₂ O ₃ content is 2 to 10% is that if it is less than 2%, the durability and corrosion resistance of the film will be insufficient, and if it exceeds 10%, it will not be possible to form an effective film.
Reason for setting B ₂ O ₃ to 5 to 15% and SiO ₂ to 50 to 15%
The reason for setting it to 78% is the same as the reason for limitation explained in the first invention. (3) The reason for the composition limitation of the third invention will be described below.
The reason for setting the total monovalent alkali component to 0.5 to 5% is that if it is less than 0.5%, it is impossible to form an effective glassy film in the temperature range of 1050 to 1250°C.
%, it becomes difficult to adjust the expansion coefficient, and at the same time, the viscosity during film formation decreases, making it impossible to form an effective glassy film that reacts with the substrate significantly.
In addition, the total amount of divalent alkaline earth metals is 0.5 to 5
% for the same reason as mentioned above. _{Al2O3 _}
The reason for setting 20 to 45% is to prevent the coated glass from reacting significantly with the substrate during high-temperature firing at 1050 to 1250℃, and because it is necessary to form a coating with good durability and corrosion resistance. If it exceeds, the composition will be
This is because it becomes difficult to form a glassy film at 1050 to 1250°C, making it difficult to form an effective film.
The reason for setting B ₂ O ₃ to 1 to 8% is that if it is less than 1%, it is difficult to form an effective glassy film, and if it exceeds 8%, the expansion of the film will be small and the film will become more easily melted. This makes it difficult to form an effective film.
The reason for setting SiO ₂ to 45 to 60% is because if it is less than 45%, it will not be possible to form a glass film with corrosion resistance, and if it exceeds 60%, it will not be possible to form a sufficient glassy film in the temperature range of 1050 to 1250℃. be. Next, the present invention will be specifically described with reference to Examples. Example 1 336 parts of anhydrous borax, 416 parts of Kanamaru feldspar, 115 parts of limestone,
Mix 84 parts of silica and 49 parts of soda ash well and heat to 1300℃±
It was melted at a temperature of 20°C, cooled with water, and then dried to obtain No. 1 frit of sodium borosilicate glass shown in Table 1. 30 parts of No. 1 frit, 50 parts of low expansion borosilicate glass
Weighed 20 parts of Frogme clay, 0.5 parts of glue, and 100 parts of water, wet mixed and pulverized, then passed through 200 mesh.
A water absorption and water permeability improver shown in Table 2 was obtained.

【table】

[Table] Dilute the obtained improver with water to 35 Baume degrees, adjust the concentration, apply it by hand to the surface of the glazed tile base, dry it, apply the glaze using the conventional method, and then oxidize it. Atmosphere tunnel furnace at 1000℃ approx.
A glazed tile coated with a water absorption and water permeability improver was obtained by firing for 24 hours. One representative of the tiles obtained was taken out and its water permeation rate was measured using the testing device shown in the drawing. The results are summarized in Table 5 together with comparative examples. Example 2 5 parts of commercially available lead silicate glass cullet, 70 parts of low-expansion borosilicate glass, 25 parts of clay, 0.5 part of sizing agent, and 100 parts of water were weighed, wet mixed and crushed, and passed through a 200-mesh sieve. In this way, leaded water absorption and water permeation improvers shown in Table 3 were obtained. After adjusting the concentration by diluting it with water to 40 Baume degrees, it is applied to the back side of the clay tile base by hand, and after drying, a glaze is applied and fired at 1150 degrees Celsius in an oxidizing tunnel furnace for about 20 hours to create a glaze. I got tiles. The results of water permeation rate are shown in Table-5.

[Table] Example 3 The water absorption and water permeation preventive agent obtained in Example 1 was applied by hand to both sides of the clay tile base at a concentration of 20 Baume degrees, fired at 950°C in a shuttle furnace in an oxidizing atmosphere, and then heated to 890°C.
The tiles were smoked in an acid atmosphere. The water permeability rate of the obtained ibushi tiles was measured. The results are shown in Table 5.
Shown below. Example 4 34 parts of low expansion borosilicate glass, 66 parts of clay, and sizing agent
0.5 parts and 100 parts of water were added, wet-milled, and passed through a 200-mesh sieve to obtain a slurry-like coating agent. The oxide composition of the obtained coating agent is shown in Table 4. After adjusting the concentration of this coating agent to 40 Baume degrees, apply it thinly and evenly to the surface of the clay tile with a brush and heat it in a shuttle furnace.
It was oxidized and fired at 980°C and then smoked in a reducing atmosphere at 850°C to obtain oxidized roof tiles. Compared to conventional products, the obtained ibushi tiles had a very smooth surface, a moderate luster, and were extremely beautiful.

[Table] Comparative Example 1 The water absorption and water permeation preventive agent obtained in Example 1 was applied to a clay tile base at a concentration of 30 Baumé degrees on one side (surface) using a hand grip and fired at 1000°C for about 24 hours in a tunnel furnace in a reducing atmosphere. Then I got a glazed roof tile that I had never seen before. This was similarly subjected to a water permeability test using the testing device shown in the drawing. The results are shown in Table-5. Comparative Example 2 A commercially available glazed tile manufactured by a normal glazed tile manufacturing method was obtained and the water permeation rate was measured in the same manner. Commercially available oxidized roof tiles were also obtained and the water permeation rate was measured in the same manner. The results are shown in Table-5.

[Table] As shown in the Examples and Comparative Examples in Table 5, the water permeation rate of tiles manufactured using the water absorption and water permeability improver of the present invention is extremely low, and the effectiveness of the present invention is clear. Further advantageous properties are also provided by implementation of the invention. That is, when the water absorption and water permeability improver of the present invention is applied and fired, a small amount of penetration occurs on the applied surface, and as a result, when applied to the surface of clay tiles, wind and rain from outdoors,
Suppresses water absorption and water permeation due to melting snow. Also, if it is applied to the back side, moisture that evaporates from indoors will be absorbed to the extent that it does not condense on the back side of the tile, and as the temperature rises, the moisture inside the tile can escape through the so-called ``breather'', causing frost damage. It has the advantage of being less dangerous.

[Brief explanation of the drawing]

The figure shows a device for testing the water absorption and permeability of clay roof tiles. 1...Glass capillary tube, 2...Sample (in plastic bag), 3...Support stand, 4...Rubber packing, 5
... Cylinder, 6 ... Tightening screw, 7 ... Tank, 8 ... Rubber tube, 9 ... Rubber stopper, C ₁ ... Two-way lock, C ₂ ... Two-way lock.

Claims (1)

[Scope of Claims] 1. The oxide composition is 2 to 10% by weight of one or more of Na ₂ O, K ₂ O, and Li ₂ O (hereinafter all weight %),
One or more of CaO, MgO, BaO, ZnO, SrO 0-8%, Al ₂ O ₃ 5-15%, B ₂ O ₃ 5-20%,
A coating agent for improving water absorption and water permeability for clay tiles, characterized by containing 50 to 78% SiO ₂ . 2 The oxide composition is 2 to 7% of one or more of Na ₂ O, K ₂ O, and Li ₂ O, including PbO, PbO and CaO,
The total amount of one or more of MgO, BaO, ZnO, and SrO is 2 to 30%, Al ₂ O ₃ 2 to 10%, B ₂ O ₃ 5 to 15
%, SiO ₂ 50-78%, for use on clay roof tiles to improve water absorption and water permeability. 3 The oxide composition is 0.5 to 5% of one or more of Na ₂ O, K ₂ O, Li ₂ O, CaO, MgO, BaO,
0.5-5% of one or more of ZnO and SrO,
A coating agent for improving water absorption and water permeability for clay roof tiles, characterized by containing 20-45% of Al ₂ O ₃ , 1-8% of B ₂ O ₃ and 45-60% of SiO ₂ .