BUILDING LARGE PORCELAIN PANEL

Abstract

An object of the present invention is to provide a building large porcelain panel that prevents the efflorescence.

As the solutions, a building large porcelain panel according to the present invention is formed by kneading a raw material formulation containing, as a main material, a refractory aggregate, a glassy raw material, and cement, and subjecting the raw material formulation to molding and then firing, wherein the building large porcelain panel has a Na.sub.2O content of 1 mass% or less in an entire chemical-component composition of the building large porcelain panel fired. In addition, the building large porcelain panel has a Na2O content of 1% or less and containing 0.5 to 7% of BaO and 0.5 to 8% of B.sub.2O.sub.3 (12% or less of the BaO and the B.sub.2O.sub.3) at mass-based chemical component values.

Claims

1. A building large porcelain panel formed by kneading a raw material formulation containing, as a main material, a refractory aggregate, a glassy raw material, and cement, and subjecting the raw material formulation to molding and then firing, the building large porcelain panel having a Na.sub.2O content of 1% or less at a mass- based chemical component value.

2. The building large porcelain panel according to claim 1, having a Na.sub.2O content of 1% or less, and containing 0.5 to 7% of BaO and 0.5 to 8% of B.sub.2O.sub.3 but 12% or less of the BaO and the B.sub.2O.sub.3 at mass-based chemical component values.

3. The building large porcelain panel according to claim 2, wherein the glassy raw material accounts for 3 to 30% of the raw material formulation.

4. The building large porcelain panel according to claim 3, wherein the glassy raw material is low soda glass having a Na.sub.2O content of 1% or less at a mass-based chemical component value.

5. The building large porcelain panel according to claim 4, wherein the glassy raw material is the low soda glass having a Na.sub.2O content of 1% or less, and containing 2 to 20% of the BaO and 2 to 30% of the B.sub.2O.sub.3 but 33% or less of the BaO and the B.sub.2O3 at mass-based chemical component values.

6. The building large porcelain panel according to claim 5, wherein a firing temperature is 1000 to 1200° C.

Description

DESCRIPTION OF EMBODIMENTS

[0024] In the present invention, the porcelain panel has a Na.sub.2O content of 1 mass% or less, further preferably 0.7 mass% or less. The porcelain panel having a Na.sub.2O content of more than this amount cannot give the efflorescence prevention effect of the present invention.

[0025] The glassy raw material used in the present invention is a raw material softened and melted into glass at about 700 to 900° C. Examples of the glassy raw material include soda glass, soda-lime glass, borosilicate glass, alumina silicate glass, borate glass, and phosphate glass. Waste glass of optical glass, heat-resistance glass, window glass, bottle glass, or vehicle glass is preferably used for an economical reason.

[0026] The glassy raw material is generally soda glass mainly containing SiO.sub.2, CaO, and Na.sub.2O, as represented by, for example, window glass, and containing about 6 to 15 mass% of the Na.sub.2O. In the present invention, the Na.sub.2O content of the porcelain panel is reduced to within the range of the present invention, and therefore low soda glass is preferably used as the glassy raw material.

[0027] The low soda glass has a Na.sub.2O content of 1 mass% or less, further preferably 0.5 mass% or less. The low soda glass having a Na.sub.2O content of more than this amount cannot give the efflorescence prevention effect.

[0028] The porcelain panel containing BaO and B.sub.2O.sub.3 has proportions of the BaO and the B.sub.2O.sub.3 of 0.5 to 7% and 0.5 to 8%, respectively (12% or less of the BaO and the B.sub.2O.sub.3). The BaO in an amount of less than 0.5% has trouble reacting with sulfuric acid, and therefore the effect brought about by the addition of the BaO becomes insufficient. The BaO in an amount of more than 7% makes it difficult for the glassy raw material to be melted and thus causes the excessive sintering. The B.sub.2O.sub.3 in an amount of less than 0.5% makes it difficult for the glassy raw material to be melted and thus causes insufficient strength of the porcelain panel. The B.sub.2O.sub.3 in an amount of more than 8% causes the excessive sintering. In addition, the BaO and the B.sub.2O.sub.3 in a total amount of more than 12% similarly cause the excessive sintering.

[0029] When the supply of the BaO and the B.sub.2O.sub.3 is attained by the glass component, the glass used for the supply is low soda glass having a Na.sub.2O content of 1 mass% or less, further preferably 0.5 mass% or less, and low soda glass further containing 2 to 20 mass% of the BaO and 2 to 30 mass% of the B.sub.2O.sub.3 is used.

[0030] The BaO and the B.sub.2O.sub.3 in contents of less than these amounts give an insufficient effect of accelerating the melting of glass not to give a further efflorescence prevention effect. The BaO and the B.sub.2O.sub.3 in contents of more than these amounts cause the excessive sintering and give poor cutting work properties. In addition, also the BaO and the B.sub.2O.sub.3 in a total amount of more than 33 mass% cause the excessive sintering.

[0031] When the low soda glass used in the present invention is waste glass, the waste glass sometimes contains a transition metal component such as Ni, Mn, or Co for the purpose of coloring or the like. The waste glass, however, does not impair the effects of the present invention as long as the total amount of the transition metal component is in the range of, for example, 5 mass% or less.

[0032] The glassy raw material preferably accounts for 3 to 30 mass% of the raw material formulation. The glassy raw material accounting for less than 3 mass% makes the porcelain panel have insufficient structural strength and gives a poor firing shrinkage prevention effect. The glassy raw material accounting for more than 30 mass% causes the excessive sintering.

[0033] Specific examples of the cement include Portland cement, alumina cement, and fly-ash cement. In the present invention, Portland cement is preferable in terms of the economic efficiency, the cure rate, and the like.

[0034] The cement accounts for preferably 5 to 40 mass%, further preferably 10 to 30 mass% of the raw material formulation. The cement contained less than this amount makes the porcelain panel have insufficient firing shrinkage prevention. The cement contained more than this amount increases the component that produces the efflorescence. Both the cases are not preferable.

[0035] The refractory aggregate is, for example, a silica-alumina refractory raw material such as chamotte, pyrophyllite, clay, silica stone, silica sand, feldspar, brick waste mainly containing these materials, or pottery roof-tile waste. As a fine powder portion, a fine powder refractory raw material, i.e., silica flour, calcined alumina, fly ash, or the like may be used. In addition, a lightweight aggregate such as shirasu balloon, Kohga stone, or pearlite may be used in combination.

[0036] These refractory aggregates contain Na.sub.2O as a minor component, and it is therefore necessary to adjust the use amount of the refractory aggregate to make the Na.sub.2O content in the entire structure of the porcelain panel fall within the range specified in the present invention.

[0037] The refractory aggregate accounts for the remaining portion of the percentage composition, except for the proportions of the glassy raw material and the cement, and has a proportion of, for example, 40 to 80 mass%.

[0038] In order to improve impact resistance, an inorganic fiber may further be added. Specific examples of the inorganic fiber include ceramic fibers such as a silica fiber, an alumina fiber, an alumina-silica fiber, and a glass fiber, and mineral fibers such as rock wool, asbestos, and sepiolite. The amount of the inorganic fiber additionally added to 100 mass% of the raw material formulation is preferably 4 mass% or less.

[0039] In the manufacturing of the porcelain panel according to the present invention, about 0.3 to 2 mass% of a binder and about 10 to 25 mass% of water are additionally added to 100 mass% of the raw material formulation, the mixture is kneaded and subsequently subjected to molding, curing, and drying, then to glazing as necessary for the purpose of coloring, and to firing by a roller hearth kiln or the like.

[0040] The type of the binder is, for example, a synthetic or natural binder such as CMC (carboxymethyl cellulose), MC (methyl cellulose), PVA (polyvinyl alcohol), dextrin, or starch. The molding method is, for example, pressure molding or extrusion molding. The firing temperature is preferably 1000 to 1200° C.

Examples

[0041] Hereinafter, examples of the present invention and comparative examples thereof are described. Table 1 shows the chemical component value of the glassy raw material used in each of the examples. Tables 2 and 3 show the composition of the raw material formulation for the porcelain panel and the test results in each of the examples. Reference signs A to G of the glassy raw materials in Table 1 correspond to the reference signs of the glassy raw material shown in Table 2.

TABLE-US-00001 TABLE 1 Chemical component value (mass %) SiO.sub.2 Al.sub.2O.sub.3 CaO MgO Na.sub.2O B.sub.2O.sub.3 BaO Others Glass A 60.3 7.9 18.3 7 0.9 1.5 1.9 2.2 Glass B 59.6 9.3 17.4 8.3 0.5 1.8 1.6 1.5 Glass C 57.8 15.4 6.4 2.7 0.2 5.2 8.8 3.5 Glass D 66.6 10.7 4.7 1.2 0.1 12.3 2.3 2.1 Glass E 56 15.4 5.5 1.4 0.2 2.1 17.7 1.7 Glass F 71.1 3.5 10.6 0.9 12.2 1.7 Glass G 60.4 6 13.4 2.6 6.5 5.2 4.1 1.8

TABLE-US-00002 TABLE 2 Example of present invention 1 2 3 4 5 6 7 8 Raw material Pyrophyllite (Na.sub.2O: 0.3%) 0.5 mm or less 30 15 30 30 30 30 30 30 formulation Chamotte (Na.sub.2O: 0.5%) 0.5 mm or less 35 30 20 35 20 20 20 20 (mass %) Glass A 0.15 mm or less 5 25 Glass B 0.15 mm or less 20 Glass C 0.15 mm or less 5 15 20 Glass D 0.15 mm or less 20 Glass E 0.15 mm or less 20 Normal Portland cement 30 30 30 30 35 30 30 30 Composition of fired Na.sub.2O content (mass %) 0.31 0.42 0.29 0.28 0.22 0.23 0.21 0.23 porcelain panel B.sub.2O.sub.3 content (mass %) 0.08 0.38 0.36 0.26 0.78 1.04 2.46 0.42 (chemical component value) BaO content (mass %) 0.08 0.48 0.32 0.44 1.32 1.76 0.46 3.54 Test Efflorescence Degree of Water temperature None None None None None None None None efflorescence 5° C. (visual inspection) Water temperature None None None None None None None None 35° C. Elution Sodium Water temperature 0.02 0.02 0.01 0.01 0 0 0 0 (mass %) content 5° C. Water temperature 0.03 0.03 0.01 0.01 0.01 0 0 0 35° C. Sulfate Water temperature 0.17 0.13 0.13 0.12 0.05 0.04 0.05 0.04 radical 5° C. Water temperature 0.18 0.16 0.15 0.15 0.06 0.04 0.07 0.05 35° C. Dimensional accuracy (linear change: %) 0 0.3 0.2 0.2 0.2 0.2 0.4 0.3

TABLE-US-00003 TABLE 3 Comparative Example 1 2 3 Raw material Pyrophyllite (Na.sub.2O: 0.3%) 0.5 mm or less 20 15 25 formulation Chamotte (Na.sub.2O: 0.5%) 0.5 mm or less 35 30 20 (mass %) Chamotte F 0.5 mm or less 15 15 Chamotte G 0.5 mm or less 25 Normal Portland cement 30 30 25 Serpentinite 15 Composition of fired Na.sub.2O content (mass %) 2.07 1.82 - porcelain panel B.sub.2O.sub.3 content (mass %) 0.00 1.30 - (chemical component value) BaO content (mass %) 0.00 1.03 - Test Efflorescence Degree of efflorescence Water temperature 5° C. Severe Moderate Slight (visual inspection) Water temperature 35° C. Severe Severe Moderate Elution Sodium Water temperature 5° C. 0.19 0.25 - (mass %) content Water temperature 35° C. 0.22 0.27 - Sulfate Water temperature 5° C. 0.3 0.22 - radical Water temperature 35° C. 0.35 0.25 - Dimensional accuracy (linear change: %) 0 0.3 - Hyphen “-” in test results represents no measurement.

[0042] In each of the examples, 1 mass% of MC (methyl cellulose) as a binder and 20 mass% of water were additionally added to the raw material formulation shown in the table, the mixture was kneaded and molded by an extruder into a product having a dimension of 20 mm (thickness) ×300 mm (width) ×2000 mm (length). Subsequently, the product was fired by a roller hearth kiln at 1100° C. for 3 hours to give a building large porcelain panel. The test methods are as follows.

[0043] Efflorescence test: a test piece obtained by cutting the building large porcelain panel into a dimension of 300 mm ×300 mm was immersed in water at water temperatures of 5° C. and 35° C. respectively for 48 hours under the assumption of seasonal changes. Then, the test piece was evaluated for appearance by visual inspection and measured for the elution amounts of the sodium content and the sulfate radical.

[0044] In the test for appearance by visual inspection, only a lower half portion of the test piece was immersed in water, and the state of efflorescence generated in an upper half portion not immersed in water was observed.

[0045] The elution amount of the sodium content was measured by immersing the entire test piece in water and measuring by an ion meter the amount of the sodium content eluted into water. The elution of the sulfate radical was measured by a precipitation gravimetric method using barium chloride. The efflorescence is more easily caused according as the elution amount of each of the components increases.

[0046] Dimensional accuracy test: the linear change along with firing shrinkage was measured from the dimension between before and after the firing. The firing shrinkage is larger according as the linear change increases.

[0047] As shown by the test results of the table, all the porcelain panel materials obtained in the examples of the present invention have an excellent efflorescence prevention effect and also have excellent dimensional accuracy. Among the examples, Examples 5 to 8 are materials containing the BaO and the B.sub.2O.sub.3 within the range of the present invention and thus have a further excellent efflorescence prevention effect.

[0048] In contrast, Comparative Example 1 corresponds to a conventional material, has a Na.sub.2O content of more than the range specified in the present invention, and thus cannot give the efflorescence prevention effect. Comparative Example 2 has a BaO content and a B.sub.2O.sub.3 content within the range of the present invention but has a Na.sub.2O content of more than the range specified in the present invention, and thus cannot give the efflorescence prevention effect.

[0049] In Comparative Example 3, the efflorescence was attempted by adding a magnesium silicate mineral, or serpentinite. Comparative Example 3, however, gives an insufficient efflorescence prevention effect.

[0050] (Effects of the invention)

[0051] The efflorescence badly damages the appearance required of the construction material. The present invention resolves the problem of the efflorescence, and the effect thereof is clear as shown by the test results of the examples. In addition, the dimensional accuracy is also satisfying. These results enable the construction large porcelain panel to exhibit every effect of durability and weather resistance.