JPH08225359A - Ceramic plate - Google Patents

Abstract

PURPOSE: To obtain a ceramic plate which is excellent in strength and shock resistance, despite that it is thin, and has high dimension accuracy with warpage and deformation reduced by specifying the coefficient of thermal expansion in a ceramic plate of a multi-layered structure which is mainly made of ceramic materials. CONSTITUTION: In a ceramic plate which is mainly made of ceramic materials and has a three-layered structure, the coefficient of thermal expansion of the plate is adjusted not over 7×10<-6> / deg.C, preferably not over 6.5×10<-6> / deg.C, and the difference in the coefficient of thermal expansion between the adjacent layers is adjusted not over 2×10<-6> / deg.C, preferably 0.2×10<-6> -2×10<-6> / deg.C, more preferably 0.5×10<-6> -1×10<-6> / deg.C. It is preferred that the coefficient of thermal expansion of the surface layer is adjusted smaller than that of the adjacent inner layer at least on one side surface layer. Further, the thickness of each layer is preferably made 0.05-2mm and the whole thickness of the fired product is more preferably set to 2-100mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic plate manufactured by a papermaking method and a manufacturing method thereof. The ceramic plate according to the present invention is excellent in strength and dimensional characteristics even if it is thin, and can be preferably used mainly as an outer wall material, an inner wall material, a floor material and the like of construction.

[0002]

2. Description of the Related Art In recent years, in the construction and furniture manufacturing industries,
The market for large ceramic plates is expanding rapidly. Large porcelain plates are easy to handle and easy to construct.
Since it is required to be lightweight, it is usually manufactured as a thin plate. However, the large porcelain plate used in the above-mentioned industry is required to have sufficient strength characteristics against external impact even if it is thin, and to have good dimensional accuracy without warping or deformation. A papermaking method is usually used to manufacture such a thin ceramic plate. For example, the method described in JP-B-60-3038 can be used. That is, a sheet for a ceramic plate having a predetermined water content produced by making a slurry containing high-earth powder and a fiber material as an essential component, and a predetermined water content produced by making a slurry having a glaze and a fiber material as an essential component This is a method in which a glaze sheet is overlaid, integrated using a roll-type press machine, and then baked.

Further, the inventors of the present invention produced thin papermaking sheets from a slurry composed of a powder of ceramic material, a fiber material and a binder component, laminated a required number of sheets, and pressed and integrated the laminated papermaking sheets. A method for producing a multilayer ceramic plate by firing and stacking sheet-like fired bodies having the same composition has been proposed (see JP-A-6-144914). This ceramic plate had small warpage and deformation, and had excellent strength characteristics.

[0004]

However, as the demand for large porcelain plates has increased and the applications have diversified, there has been a demand for new sophistication of quality and cost reduction. The present inventor, as a result of examining means for responding to such a demand, came to the conclusion that it is desirable to make progress based on the ceramic plate and the manufacturing method thereof described in JP-A-6-144914, By continuing research, it was possible to complete the ceramic plate of the present invention, which is excellent in impact resistance and strength characteristics, has less warpage and deformation, and has high dimensional accuracy, and a manufacturing method thereof.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a ceramic plate having at least a three-layer structure whose main component is a ceramic material,
The coefficient of thermal expansion of the ceramic plate does not exceed 7 × 10 ^-6 / ° C, and the difference in coefficient of thermal expansion between adjacent layers is 2 × 10 ^-6 /
Provided is a ceramic plate characterized by not exceeding ℃. In the ceramic plate of the present invention, in at least one surface layer, the coefficient of thermal expansion of the surface layer is preferably smaller than that of the adjacent inner layer, and the thickness range of each layer is preferably 0.05 to 2 mm. is there. The thickness range of the entire fired body is preferably 2 to 10 mm, particularly preferably 3 to 8 mm. Also,
By mixing a coloring material in at least one surface layer of the ceramic plate, for example, a beautiful aesthetic like natural stone can be obtained.

Further, according to the present invention, a powder of ceramic material, a fiber material, and a thermoplastic organic material having a glass transition point not exceeding 10 ° C. are essential components and are formed into layers having different thermal expansion coefficients after firing. At least 2
A step of adjusting various kinds of slurries, a step of forming each slurry into a sheet-shaped molded body, a step of preheating each sheet-shaped molded body to at least 50 ° C., and laminating each sheet-shaped molded body at least Provided is a method for producing a ceramic plate, which comprises a step of forming a laminated body having a three-layer structure and a step of pressurizing the laminated body to integrate the sheet-shaped formed body and then firing. In the present invention, regardless of the surface layer or the intermediate layer, layers having substantially the same coefficient of thermal expansion can be laminated, but the term “adjacent layers” means the coefficient of thermal expansion unless otherwise specified. Indicate different adjacent layers, and do not mean adjacent layers having substantially the same coefficient of thermal expansion.

[0007]

Actions and Embodiments The construction, action and manufacturing method of the ceramic plate according to the present invention will be described in detail with reference to embodiments. The ceramic plate of the present invention varies depending on the thickness and composition, but it is realistic to stack at least three layers, or about 5 to 20 layers in the current technical level. The coefficient of thermal expansion of at least one layer is different from the coefficient of thermal expansion of the other layers, and the coefficient of thermal expansion of the entire fired body is adjusted to a required value, and as a result, the occurrence of warpage or deformation of the ceramic plate is suppressed. And the strength characteristics are improved.

First, the function and mode of thermal expansion of the ceramic plate of the present invention will be described. The ceramic plate of the present invention can be manufactured by stacking at least three layers of papermaking sheets and firing. At least two layers of the layers constituting the ceramic plate after firing have different thermal expansion coefficients (hereinafter, abbreviated as layers having different thermal expansion). The layers having different thermal expansions shrink with different thermal shrinkages depending on the difference in composition and the firing conditions during the firing process. As a result, strain stress due to the difference in shrinkage is inherent in the two-layer bonded surface of the ceramic plate having different thermal expansions. Therefore, even if an impact force is applied to the ceramic plate from the outside, the impact force is dispersed at the joint surface where strain stress is inherent,
It produces an effect of preventing the occurrence of cracks. Further, between two adjacent layers having different thermal expansion coefficients, a compressive stress is generated in a layer having a small thermal expansion coefficient during firing, and a tensile stress is generated in a layer having a large thermal expansion coefficient. Therefore, if the stresses generated in both layers are optimized,
The strength of the ceramic plate can be improved by causing the effect of preventing the ceramic plate from being warped or deformed. Further, when the coefficient of thermal expansion of the surface layer of the ceramic plate is set to be smaller than the coefficient of thermal expansion of the intermediate layer, compressive stress is generated in the surface layer having a small coefficient of thermal expansion, and the surface strength is improved. Further, since the shrinkage of the surface layer is small, it is considered that the surface tends to have a gentle convex shape to prevent the end portion from warping.

In the ceramic plate of the present invention, the difference in coefficient of thermal expansion between adjacent layers is 0.2 × 10 ⁻⁶ to 2 × 10 ⁻⁶ / ° C., particularly 0.5 × 10 ⁻⁶ to 1 × 10 ^−6. It is preferably adjusted within the range of / ° C. If the difference in the coefficient of thermal expansion is too small, the effect based on the difference in the coefficient of thermal expansion will not be sufficient, and if it is too large, phase separation and cracks will occur during the firing process, and warping and deformation will occur. Further, it is preferable to adjust the thermal expansion coefficient of the entire fired body not to exceed 7 × 10 ⁻⁶ / ° C., preferably 6.5 × 10 ⁻⁶ / ° C. This is because generation of cooling cracks during firing can be suppressed, warpage and deformation can be reduced, and strength, impact resistance, and thermal shock resistance can be improved.
In addition, there is also an advantage that productivity can be improved because the cooling rate in the firing step can be increased in manufacturing the ceramic plate.

A method for measuring the coefficient of thermal expansion of each layer constituting the ceramic plate of the present invention will be described. Since each layer of the ceramic plate, at least the layer having different thermal expansion, has a different pore structure, when dye water is impregnated from the surface, the dyeing of each layer becomes shaded. The boundary of each layer can be identified by magnifying and observing the boundary of light and shade with a microfiberscope, for example. When the difference in the pore structure of the adjacent layers is too small to discriminate the tint of staining, EPMA (electron probe X-ray microanalyzer) is used to measure the difference in the composition of each layer to identify the boundary. Once the boundaries of each layer have been identified, the ceramic plate can be sliced along the boundaries and a measurement sample can be taken from the layer to be measured. A sample for measuring the coefficient of thermal expansion of the entire fired body is cut as it is and collected without slicing. The sample collected was measured from room temperature (t ₀ ) to a predetermined temperature (t: 70) using a commercially available push rod type differential thermal expansion meter.
Increase the temperature to 0 ° C and increase the length of the sample (at room temperature:
l ₀ , at t ° C .: 1) is measured and calculated by the following formula.

Α (coefficient of thermal expansion) = (l−l ₀ ) / {l ·
(T−t ₀ )} The thickness of each layer constituting the ceramic plate of the present invention is 0.05 to
2 mm is preferable, and the thickness of the whole fired body depends on the purpose of use and the surface area of the ceramic plate, but is preferably in the range of 2 to 10 mm, particularly preferably in the range of 3 to 8 mm. The thickness of the ceramic plate is usually adjusted by laminating a required number of thin sheet-shaped molded products, integrating them under pressure, and firing. If the thickness of each layer is less than 0.05 mm, it may be difficult to produce a uniform sheet, and if it is more than 2 mm, it may be difficult to obtain good quality. The thickness of each layer does not have to be the same.
Further, if the thickness of the entire fired body is less than 1 mm, cracking or warpage easily occurs, and if it is more than 10 mm, firing becomes difficult.

In the ceramic plate of the present invention, kaolin, various clays, porcelain stone, silica stone, wollastonite, feldspar, dolomite, alumina, zirconia, ferrite and other inorganic substances are used alone or as a main component in the ceramic raw material. use. In the present invention, the coefficient of thermal expansion of the ceramic plate can be adjusted mainly by the composition of the ceramic raw material used, the particle size distribution and the like. The content of the alkali metal oxide in the ceramic plate for increasing the coefficient of thermal expansion does not exceed 7% by weight, and
Content of crystalline quartz remaining in the ceramic plate is 10% by weight
It is preferable to adjust the raw materials so as not to exceed the above.

By incorporating a pigment into at least the surface layer of the ceramic plate of the present invention, a ceramic plate having an arbitrary color can be obtained. Alternatively, pigments of different colors may be mixed in the surface layers on both sides to provide various color effects to the ceramic plate. Further, when the surface layer is formed by superposing a plurality of ultrathin layers having different colors, it is possible to obtain a ceramic plate having a marble-like pattern in which a portion where each color is seen and a portion where it is seen through are complicated. When pigments of various colors are dispersed in scales or spots and added to the raw material slurry for the surface layer, a natural granite-like ceramic plate is obtained. The thickness of the colored layer or the pattern layer on the surface can be determined according to the application, but when polishing the surface to impart gloss, the surface layer after firing should have a thickness of at least 0.5 mm. Is desirable.

Next, a preferred method for manufacturing a ceramic plate of the present invention will be specifically described with reference to embodiments. First, a thermoplastic organic material (hereinafter, abbreviated as an organic material) in which a powder of a ceramic raw material and a fiber material having a predetermined mixing ratio are added to water, and further, a glass transition point of a predetermined amount does not exceed 10 ° C.
Is added, and the mixture is stirred and mixed using a pulper or the like to form a slurry. The fiber material is mainly used for making a ceramic raw material or for reinforcing the strength of a ceramic plate. Specifically, natural fibers, natural and synthetic pulp, rayon, vinyl alcohol polymers, various organic synthetic fibers such as polyester, glass fibers, ceramic fibers,
Various inorganic fibers such as rock wool and potassium titanate can be used. Since the inorganic fiber does not disappear by firing, it has an action of preventing shrinkage during firing and improving the strength of the product. These fibers may be mixed and used. The organic material has a function of reducing the porosity of the ceramic body.
Examples of the organic material include natural rubbers, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, polyacrylic acid esters, and other organic polymers having a glass transition point not exceeding 10 ° C.

The mixing ratio of the slurry varies depending on the structure of the ceramic plate and the purpose of use, but a preferable composition is as follows:
It is advisable to add 1 to 25 parts by weight of the fiber material and 1 to 50% by weight of the organic material to 100 parts by weight of the ceramic material to mix them. In this composition, a relatively large amount of ceramic material and fiber material are included, and even if the porosity is small, an appropriate amount of organic material is blended, so that the obtained laminate has flexibility, and as a whole, Easy to handle. When the amount of the fiber material is small, it becomes difficult to make the paper, and when the amount of the fiber material is excessively large, shrinkage deformation and warpage of the ceramic plate due to the loss of the fiber material increase. If the compounding amount of the organic material is 1% by weight or less, the effect of addition is not sufficient, and if it exceeds 50% by weight, shrinkage in the firing step becomes large, which is not preferable.

In addition to the above three components, various chemicals can be added to the slurry in order to improve the characteristics of the ceramic plate and the operability during manufacturing. For example, anionic organic polymer electrolytes, cationic organic electrolytes, cationic inorganic colloids, fixing agents and flocculants such as polyvalent metal salts; various pigments, colored fine particles, surface makeup such as granite powder Material: Asbestos fiber, glass fiber, wollastonite.

In the present manufacturing method, at least two kinds of slurries containing the ceramic material powder, the fiber material and the organic material as essential components are prepared in order to impart a difference in thermal expansion coefficient between the layers of the ceramic plate. That is, when the respective slurries to be prepared are made into paper, and the obtained sheet-shaped compacts are laminated and integrated and fired, at least two layers of the layers constituting the ceramic plate differ in thermal expansion coefficient within mutually preferable ranges. Adjust to and mix.

Next, the prepared slurry is formed into a sheet-shaped compact by using, for example, a Fourdrinier or round-net machine. Each of the sheet-shaped compacts produced is laminated in a required number of layers of three layers or more, and pressurized to be integrated. It is preferable to preheat the sheet-shaped molded product to at least 50 ° C. before pressurizing. This is because it is possible to obtain a base material for a ceramic plate that is dense and has less distortion at a lower pressure. Usually, it is heated to a temperature higher than the glass transition point of the organic polymer blended as a raw material by 50 ° C. or higher. A hydraulic press or a mechanical press can be used for the pressing operation, but in the present invention, it is preferable to use a roll press that can uniformly and continuously apply a large linear pressure to the long sheet.

The resulting pressure-laminated product has a porosity of 0.1 to 0.1.
0.4, the water absorption is 10 to 30% by weight, and more preferably 15 to 25%. The porosity and the water absorption can be adjusted depending on the slurry composition and the pressurization condition of the laminate. Roll press linear pressure is 10
When it is 0 kg / cm or less, it is difficult to adjust the porosity to the range of 0.1 to 0.4. By setting the porosity to 0.4 or less, shrinkage during firing is suppressed, and a ceramic plate having a smooth surface without warping or deformation can be manufactured. When the porosity is 0.1 or less, the ceramic plate base material is excessively compressed, and residual stress in the base material easily causes cracking or warpage during firing. If the water absorption is too large, the shrinkage during firing will be too large, and if it is too small, the ceramic plate base material will tend to be highly compressed.

The porosity in the present invention is defined by the following (2)
From the equation, the water absorption rate is the value obtained from the equation (3). Porosity = 1- [W ₀ / V ₀ ] / [(W ₁ · ρ ₁ + W ₂ · ρ ₂ ) / W ₀ ] (2) However, V ₀ : 105 ° C., after drying for 24 hours Sample volume [cm ³ ] W ₀ : same as above [g] W ₁ : 400 ° C, weight loss of sample after drying for 2 hours [g] W ₂ : 400 ° C, weight of sample after drying for 2 hours [ g] ρ ₁ : Density [g / cm ³ ] of the organic raw material contained in the sample ρ ₂ : Density [g / cm ³ ] of the inorganic raw material contained in the sample Water absorption rate (wt%) = {(weight after water absorption− (Weight before water absorption) / weight before water absorption} × 100 (3) The thickness of a ceramic plate is usually obtained by laminating a required number of thin sheet-shaped compacts so as to have a desired thickness after firing. The pressure may be integrated for adjustment. The stacking and pressurizing operations can be performed in several stages. When performed separately, since the sheet-shaped molded product that has been pressure-processed does not have good binding properties, it is possible to sandwich the unprocessed sheet-shaped molded product for pressure integration.
Further, it is preferable to stack an unprocessed sheet on at least one side of the pressure-processed sheet to integrate the sheet under pressure. In addition, a sheet material such as a glass cloth or a glass mat is sandwiched as an adhesive component between at least two ceramic plates or a ceramic plate which has been temporarily calcined, or ceramic material powder is evenly dispersed to bond them. If it is baked at a temperature at which is melted, it can be firmly bonded and integrated.

Then, the integrated laminated body is fired using a roller hearth kiln, a tunnel kiln or the like. The roller hearth kiln can be preferably used because a long sheet-shaped laminate can be uniformly and efficiently fired continuously. The integrated laminate passes through the preheat zone, the firing zone and the cooling zone set to an appropriate temperature in the roller hearth kiln in succession successively at an appropriate time, and quickly removes the generated decomposition gas, Each sheet-shaped compact is converted into a sheet-shaped fired body and fired into the ceramic plate of the present invention. It is desirable to arrange the rollers in the firing zone at a pitch of 50 mm or less in order to prevent the sheet-like material passing over the rollers from hanging down.

The firing temperature is determined depending on the desired characteristics, etc., but is usually 1000 to 1350 ° C., preferably 11
It is in the range of 50 to 1250 ° C. In the pretropical zone, it is better to raise the temperature under mild conditions. Above all, the rate of temperature rise in the temperature range of normal temperature to 250 ° C. is preferably 50 ° C./min or less,
More preferably at 40 ° C / min or less, and 250 to 50
The rate of temperature increase in the temperature range of 0 ° C is preferably 20 ° C /
It is set to not more than minutes, more preferably not more than 10 ° C./minute.
If the heating rate in these temperature ranges is too fast, decomposition gas due to the thermal decomposition of the organic fibers and thermoplastic organic materials in the laminate will suddenly occur, or delamination between the sheet-like fired bodies due to abnormal heat generation Will occur frequently. Further, in the cooling zone, the rate of temperature decrease is set to preferably 20 ° C./min or less, more preferably 10 ° C./min or less, especially in the temperature range of 700 to 300 ° C. If the rate of temperature decrease is too fast, a large shear stress is generated between the layers of the fired body, which causes delamination and cracks.

The ceramic plate according to the present invention can be easily surface-treated. For example, when laminating and pressing sheet-shaped compacts, an embossing roll is used as a pressure machine to give an uneven pattern to the surface, or a glaze paper or a film for pattern printing is attached to form various patterns on the surface of a ceramic plate. Can be given. Various patterns can be formed by fusing glass beads or flakes, glass fabrics having various patterns, fine granite powder, etc. on the surface. In addition, the pressed surface may be ground to form an uneven pattern, may be ground or sandblasted to roughen the surface, may be machined into various shapes on the end surface, or may be formed with grooves or dovetails on the back surface, or may be drilled. A wide variety of ceramic plates can be manufactured by processing screw holes or bending into various shapes and then firing.

The laminated body after processing is, for example, 1100 to 1
If the above-mentioned processing is performed after temporarily calcining at a temperature of 350 ° C., it is possible to efficiently manufacture a ceramic plate with high dimensional accuracy. Also, spray glaze on the surface,
Printed in a pattern and then baked, or 80
After calcining at 0 to 1350 ° C., the surface thereof is glazed with the same glaze, and then calcined at 500 to 1350 ° C. to manufacture a glazed ceramic plate. In addition to the above, the ceramic plate of the present invention is composited with various materials according to the application, for example, calcareous plate, ALC, concrete plate, GRC plate, gypsum board, plywood, wood, stainless steel plate, steel plate, plastic plate, glass plate and the like. It can be used after being converted.

[0025]

EXAMPLE A ceramic plate of the present invention and a ceramic plate similar to the present invention, which is not the present invention, were manufactured as comparative examples, and will be described in order. Example 1 and Comparative Examples 1 and 2 In this example, a multilayer-structured ceramic plate of the present invention having different thermal expansion coefficients between layers was manufactured, and the mechanical properties and the like were measured. Further, as a comparative example, a ceramic plate having a multilayer structure in which each layer has the same coefficient of thermal expansion was manufactured, and the characteristics and the like were compared. 55 parts by weight of upright, 15 parts by weight of kaolin, 15 parts of alumina
Part, 5 parts by weight of talc, 10 parts by weight of wollastonite, a ceramic material powder, 5 parts by weight of kraft pulp, and 5 parts by weight of styrene-butadiene rubber latex (SBR latex, but glass transition point: -20 ° C). And water were stirred and mixed to prepare a slurry (A) having a solid content concentration of 2% by weight. Similarly, a ceramic material powder consisting of 65 parts by weight of uprite, 10 parts by weight of kaolin, 20 parts by weight of alumina, 5 parts by weight of talc, and 10 parts by weight of wollastonite was used, and the other components and the adjusting method were the same as those of the slurry (A). To prepare a slurry (B) having a solid content concentration of 2% by weight. Hereinafter, for example, (A) is added to the sheet-shaped molded product and the fired product using the slurry (A) as a starting material, and the same applies to other slurries and the like.

Using a Fourdrinier paper machine, an endless sheet having a width of 120 cm was made from each of the slurries (A) and (B), and a thickness of 2 m was obtained through a multi-cylinder dryer.
m, and a sheet-shaped molded product (A) and (B) having a water content of 0.5% by weight were produced (hereinafter, the sheet-shaped molded product is simply referred to as a molded product). The molded bodies (A) and (B) were alternately laminated to form a five-layer laminated body, and then the mixture was pressed through a hydraulic roll press having a linear pressure of 350 kg / cm. The obtained pressure laminated body was cut into a length of 3 m, a width of 1.2 m, and a thickness of 7 mm, and the porosity and the water absorption were measured according to the methods described above. Using a roller hearth kiln to cut the pressure laminated body, 1220
It was fired at 60 ° C. for 60 minutes to obtain a ceramic plate having a five-layer structure in which sheet-like fired bodies (A) and (B) were alternately laminated and integrated. Samples of the fired bodies (A) and (B) were taken from the fired ceramic plate, and the thermal expansion coefficient (based on the above-described measurement method), bending strength (based on JIS A5209) and impact strength (based on JIS K7111) were respectively taken. Was measured. Further, the warpage and deformation of the ceramic plate were evaluated by a 5-step evaluation (5 is the best).

Next, for comparison, a ceramic plate consisting of five layers of only the fired body (A) or (B) was manufactured by the same method as above, and measured and evaluated as Comparative Examples 1 and 2.

The above results are summarized in Table 1. The ceramic plate of the present invention has excellent bending strength and impact resistance, and is free from warpage and deformation.

Examples 2 to 5 and Comparative Examples 3 and 4 These examples and comparative examples mainly have a thermal expansion coefficient of 7 ×.
It was carried out in order to compare a ceramic plate that does not exceed 10 ^-6 / ° C. and a ceramic plate that does not exceed 10 ⁻⁶ / ° C., and to know the influence of the difference in the coefficient of thermal expansion between layers. The solid content concentration including the components having the composition shown in Table 2 is 2
Weighted slurries (C) to (H) were prepared, and molded bodies (C) to (H) were produced in the same manner as in Example 1. further,
These molded bodies were alternately laminated in the constitution shown in Table 3, and the laminated body was pressure-integrated in the same manner as in Example 1 and fired on a ceramic plate. During this period, measurement for evaluation was performed. The measurement results are summarized in Tables 3 and 4. The ceramic plate of the present invention has excellent bending strength and impact resistance, and is free from warpage and deformation. Coefficient of thermal expansion is 7 × 10 ^-6 / ° C
It is preferable that the ceramic plate not exceeding 10 has excellent strength characteristics, and the difference in coefficient of thermal expansion between layers is 0.2 × 10 ^{−6 to} 2.0 × 10 ⁻⁶ / ° C.

Examples 6 to 8 In these Examples, the same composition and method as in Example 1 were used except that the thickness of the molded body and the number of layers of the laminate were changed and the molded body (A) was used as the surface layer. A ceramic plate was manufactured in and the required physical properties were measured. The measurement results are shown in Table 5. It can be seen that the strength characteristics tend to improve as the number of laminated ceramic plates increases.

Examples 9-10, Reference Example These examples are the same as those in Example 1 except that the binder (SBR
A ceramic plate was manufactured in the same manner as in Example 1 except that the pressure applied to the laminate was changed to that using latex) and the physical properties were measured. Table 6 shows the changed conditions and the measurement results of the physical properties. In addition,
As a reference example, an example in which no binder is added is shown.

Examples 11 to 14 Ceramic plates were manufactured under the same conditions as in Example 1 except that the setting conditions of the surface temperature and the linear pressure of the calendar roll were changed, and the physical properties were measured. Table 7 shows the changed conditions and the measurement results. It can be seen that when the formed body is heated and laminated and pressed, a ceramic plate having excellent strength characteristics can be manufactured even if the linear pressure of the calendar roll is lowered.

Example 15 In addition to the slurry (A) prepared in Example 1,
Except for adding 2 parts by weight of cobalt oxide type blue pigment,
A ceramic plate was manufactured in the same manner as in Example 1. The produced ceramic plate had excellent strength characteristics similar to those of the ceramic plate produced in Example 1, and had a beautiful blue color on both the front and back surfaces. This ceramic plate was suitable as an interior or exterior material for construction in terms of characteristics and appearance.

Example 16 In addition to the slurry (A) prepared in Example 1,
A fine powder of granite was mixed in an amount of 10 parts by weight, and a molded body was obtained in the same manner as in Example 1. A ceramic plate was manufactured in the same manner as in Example 1 except that the molded body (A) for the surface layer was replaced with the molded body. The produced ceramic plate had the same excellent bending strength and impact resistance as the ceramic plate produced in Example 1, and the surface was a beautiful granite tone. This ceramic plate was suitable as an interior or exterior material for construction in terms of characteristics and appearance.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

[0042]

EFFECTS OF THE INVENTION The present invention provides a multi-layered ceramic plate having a large shape, a thin shape, and excellent strength characteristics by adjusting at least one manufacturing condition of inserting at least one layer having a different thermal expansion coefficient. Is. Depending on the application, the surface can be easily finished beautifully, so it can be used for a wide range of purposes such as interior and exterior materials for architecture, floor materials, furniture and laboratory tabletops, counters, various interior materials, tunnel interior materials, and civil engineering-related materials. It can be used for various purposes and has great industrial utility value.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C04B 33/13 8913-2E E04F 13/14 103A E04F 13/14 103 B28B 11/00 Z (72) Inventor Masao Noda 1-1-1, Sonoyama, Otsu City, Shiga Prefecture Toray Co., Ltd. Shiga Business Site (72) Inventor Gen Kimura 1-1-1, Sonoyama, Otsu City, Shiga Prefecture Toray Co., Ltd. Shiga Business Site (72) Inventor Shigekazu Murata 1-2-4 Ono Asahi, Shiga-cho, Shiga-gun, Shiga (72) Inventor Teruki Ueda 388 Nagahara, Yasu-cho, Yasu-gun, Shiga

Claims (6)

[Claims] 1. A ceramic plate having a structure of at least three layers, which comprises a ceramic material as a main component, wherein the coefficient of thermal expansion of the ceramic plate is 7 ×.
10 ^-6 / ° C. without exceeding, and ceramic plate, wherein a difference in thermal expansion coefficients of adjacent layers does not exceed 2 × 10 ^-6 / ℃. 2. The ceramic plate according to claim 1, wherein the thermal expansion coefficient of the surface layer is smaller than the thermal expansion coefficient of the adjacent inner layer in at least one surface layer. 3. The ceramic plate according to claim 1 or 2, wherein each layer has a thickness of 0.05 to 2 mm. 4. The ceramic plate according to claim 1, 2 or 3, wherein the thickness of the entire fired body is 2 to 10 mm. 5. The ceramic plate according to any one of claims 1 to 4, wherein a coloring material is mixed in at least one surface layer. 6. A ceramic material powder, a fiber material, and a thermoplastic organic material having a glass transition point not exceeding 10 ° C., which are essential components, and are formed into layers having different thermal expansion coefficients after firing. At least 5 steps of adjusting two kinds of slurries, making each of the slurries into a sheet-shaped molded body
It includes a step of preheating to 0 ° C., a step of laminating each sheet-shaped molded body to form a laminated body having at least a three-layer structure, and a step of pressurizing the laminated body to integrate the sheet-shaped molded body and then firing. A method for manufacturing a ceramic plate, comprising: