JP2011116568A - Ceramic base for sanitary ware - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic base for sanitary ware which is suitable for making sanitary ware thinner and lightweight and has all of high strength, low firing deformation and high thermal shock resistance. <P>SOLUTION: The ceramic base for sanitary ware is a ceramic base for sanitary ware that comprises a glass phase and a crystal phase, wherein the main crystal phase constituent is quartz. The probability of the presence of quartz grains of ≥80 μm is one or fewer per 1 mm<SP>2</SP>when 10 or more images with a 1 mm<SP>2</SP>or greater visual field are observed by laser microscope (10X objective lens). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ceramic body for sanitary ware and a method for manufacturing sanitary ware, and in particular, enables sanitary ware to be thin and lightweight, has high firing strength, has a small amount of thermal deformation during firing, and has excellent thermal shock resistance. The invention also relates to a ceramic body for sanitary ware having a low water absorption rate.

  Sanitary ware is characterized by its large and complex shape, especially among ceramic products. In such a large complex shape product, the thickness is 9 to 12 mm in order to reduce the thermal deformation during firing and to ensure the strength because there is a portion that is partially loaded by bolting and fixing. A degree was needed. For this reason, sanitary ware has a problem that it is heavy and requires a heavy work load, and its thin and light weight is required. To make sanitary ware thinner and lighter, it can be estimated that the bending strength is proportional to the square of the thickness, so that the firing strength of the substrate can be increased, and the amount of firing deformation can be estimated to be inversely proportional to the square of the thickness. Both of the problems of reducing the amount of firing deformation must first be solved.

  Various methods are conceivable as a method for increasing the firing strength of such a ceramic body and a method for reducing the firing deformation. However, as a restriction condition unique to sanitary ware, it is required that the base material is required to have high thermal shock resistance. . The thermal shock mentioned here includes a thermal shock as when pouring hot water into the basin, but more important is the thermal shock during firing. Thermal shock during firing occurs particularly at the stage of lowering the temperature. For example, although the temperature inside the product is still high, the temperature of the product surface decreases, and the thermal shock generated by this temperature difference. In large-sized products such as sanitary ware, prevention of the occurrence of cracks (kiln sharks) due to this thermal shock is a major issue.

The conventional ceramic body for sanitary ware has quartz and mullite as its main crystal phases, and these crystal phases and SiO ₂ , Al ₂ O ₃ , and alkali metal oxides / alkaline earth metal oxides filling the gaps are used. It consists of a glass phase as the main component. Such a ceramic body is formed by firing and firing ceramic body raw material particles mainly composed of a fired flux raw material such as porcelain quartzite, silica sand, clay, and feldspar, so that raw materials other than quartz melt and SiO ₂ , Al A glass phase mainly composed of ₂ O ₃ and alkali metal oxide / alkaline earth metal oxide is formed, and this glass phase is formed by filling the particle gap. In the firing process, a part of quartz is dissolved in the glass phase, and mullite is precipitated from the glass phase, so that the undissolved quartz and mullite are used as the crystalline phase to fill the gap, and the pores. A substrate structure consisting of

  Quartz particles left undissolved in the substrate generate a large tensile stress at the interface with the glass phase due to the difference in thermal expansion between the quartz and the glass phase during the cooling process of firing. It is known that micro cracks (micro cracks) are formed in the quartz particles or at the interface due to this stress, and the micro cracks are generated due to the presence of a very small amount of coarse quartz particles in the raw material, which greatly impairs the substrate strength. . (See Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3.) However, the occurrence of microcracks also has an advantage in the manufacture of large complex shaped products such as sanitary ware. In other words, a large number of quartz particles with microcracks exist in conventional sanitary ware bases, and while these microcracks reduce the base strength, they have excellent thermal shock resistance by reducing thermal shock stress. It is thought to express sex. Therefore, the conventional bending strength for sanitary ware was about 40 to 80 MPa.

  Research on improving the substrate strength by replacing corundum with quartz that causes a decrease in the substrate strength has been carried out in the world of porcelain and has already been partially put into practical use in the world of tableware and insulators. Specifically, about 10 to 60 wt% of corundum (α-alumina) is blended in the porcelain raw material, and the mechanical strength is 100 MPa or more as a bending strength (see, for example, Patent Document 1). This strength increases as the corundum content increases.

On the other hand, as a method for reducing the firing deformation amount of the substrate, a method of atomizing the substrate raw material in the substrate containing the corundum as described above is disclosed (for example, see Patent Document 2). This method utilizes the fact that the sinterability of the substrate is improved by atomizing the substrate raw material, thereby reducing the amount of the calcination flux to be added and reducing deformation due to the softening of the substrate at the time of calcination.
However, in this method, the quartz particles in the substrate also become fine particles, so the amount of microcracks generated in the quartz particles is reduced, and the thermal shock resistance of the substrate is reduced. The reason why the microcracks are not generated when the quartz particles are small is considered to be that the stress generated by the difference in thermal expansion coefficient from the glass phase is also small. As a method for preventing this decrease in thermal shock resistance, a method for preventing the atomization of quartz in the substrate by post-adding and mixing a quartz raw material such as silica sand whose particle size is adjusted (for example, patents) is also disclosed. Reference 2).

  Moreover, it is known that the method of atomizing the base material is effective in improving the strength of the base material. Regarding the mechanism of strength improvement by atomization of the raw material, one is due to the reduction of defects such as coarse particles and pores remaining in the base material, and the involvement of quartz particles in the base material is considered. In a substrate containing quartz in the substrate, such as a substrate made of porcelain stone, clay, and feldspar, microcracks in the quartz particles or at the interface between the quartz particles and the glass phase decrease as the substrate material is atomized. A microcrack is a kind of defect existing in the substrate, and reduces the strength of the substrate. Therefore, a reduction in the amount of microcracks leads to an improvement in substrate strength. In addition, due to the reduction of microcracks, the stress caused by the difference in thermal expansion between quartz and glass phase, which was not released due to the occurrence of microcracks, remains at the interface between quartz and glass phase, and this residual stress increases the substrate strength. It is thought to work to improve. Therefore, the presence of quartz particles in the substrate brings about an effect of further improving the strength by atomizing the substrate raw material. However, this is the problem of lowering thermal shock resistance and the opposite effect.

  In the strength improvement means by corundum blending as described above, the strength increases as the corundum blending amount increases, but the following two problems occur. The first problem is that corundum is heavier than quartz or glass phase, so even if you try to make it stronger and thinner and lighter, the specific gravity of the substrate will increase and the weight will be substantially reduced. It is not connected. The second problem is that a raw material containing a large amount of corundum such as alumina is expensive. In order to solve these problems, a method of using a natural ore raw material that generates corundum and mullite when calcined as a raw material containing corundum or a raw material that is calcined to generate corundum and mullite is also disclosed (for example, (See Patent Document 3 and Patent Document 4). However, even with this method, weight increase due to mixing of corundum is inevitable, and such natural raw materials are cheaper than alumina, but are the raw materials usually used for sanitary ware, pottery stone, clay and feldspar. It is still expensive compared to etc.

  In addition, the method of improving strength by reducing the atomization of raw materials and adjusting the amount of flux reduces the thermal shock resistance of the substrate, which causes kiln sharks due to heat shock during cooling during firing. In addition, there is a problem that the effect of high strength cannot be obtained as in the case of a corundum-containing base.

  In order to solve such problems, a method of reducing the amount of deformation during firing and reducing the thermal expansion coefficient of the substrate is also disclosed (see, for example, Patent Document 5). With this method, it is possible to produce a substrate with high strength and small firing deformation without increasing the blending amount of corundum that leads to increase in specific gravity and price, but in terms of improving thermal shock resistance Kiln sharks are more likely to occur due to inconsistent factors such as differences in brands and lots of natural raw materials.

  As another method for reducing the amount of deformation during firing, a method of reducing the amount of glass phase by using a material with a small loss on ignition, reducing the shrinkage during firing and suppressing the deformation during firing is also disclosed. (For example, refer to Patent Document 6). However, if this method is adopted, raw materials such as chamotte that are difficult to bake down must be used, so the water absorption rate of the calcined base is very large, about 15 to 20%. When used as sanitary ware, there are problems with frost damage and contamination resistance.

JP-A-2-275533 (page 2-4, table 3) JP-A-6-56516 (page 4-6, Table 1) Republished patent WO96 / 09996 (pages 6-11) Republished patent WO97 / 26223 (pages 17-22) Republished patent WO99 / 43628 JP 2002-114565 (page 5-6, FIG. 9) Journal of the Ceramic Society of Japan, February 1991, pages 153-157 Journal of the Ceramic Society of Japan, November 1991, 1110-1113 Journal of the Ceramic Society of Japan August 1992, pages 1066-1069

  The present invention has been made in order to solve the above-mentioned problems, and the object of the present invention is to provide a high thermal shock resistance that is particularly suitable for reduction in thickness and weight, has a small amount of firing deformation, and does not generate kiln sharks. It is to provide a sanitary ware body with.

In order to achieve the above object, according to the first aspect of the present invention, there is provided a ceramic body for sanitary ware comprising a glass phase and a crystal phase, wherein the main component of the crystal phase is quartz, The existence probability of quartz particles of 80 μm or more is 1 or less per 1 mm ² when the cut surface is observed with a laser microscope (10 × objective lens) in a field of view of 1 mm ² or more for 10 screens or more. By providing a ceramic base material for sanitary ware, it is possible to prevent a decrease in strength due to the occurrence of microcracks without accompanying the atomization of the entire quartz particles that impair the thermal shock resistance of the base material. In spite of this, it became possible to produce sanitary ware with a small amount of firing deformation and high thermal shock resistance.

  Further, according to the invention described in claim 2, the hygroscopic rate of the sanitary ware ceramic body is 3 wt% or less without using a raw material such as chamotte which increases the water absorption rate. Since a ceramic body can be provided, both high strength and resistance to contamination and frost damage can be achieved.

  Further, according to the invention described in claim 3, since the strength reduction due to the generation of microcracks can be prevented by removing the coarse quartz component, the unglazed bending strength of the ceramic body for sanitary ware is 100 MPa or more. This makes it possible to provide a sanitary ware ceramic body, which can achieve sanitary ware thickness reduction without risk of damage.

Further, according to the invention of claim 4, wherein the composition of the main component of the sanitary ware for ceramic green body _{SiO 2: 45~69wt%, Al 2} O 3: a 20 to 45 wt%, _Na 2 O, The sum of at least one component selected from the group consisting of K ₂ O and Li ₂ O and at least one component selected from the group consisting of CaO, MgO, and BaO: 3 to 6 wt%, and the crystal phase The main component includes the quartz and mullite, or quartz, mullite, and corundum, the quartz content is 5 to 30 wt%, the mullite content is 10 to 30 wt%, and the corundum content is By providing a ceramic body for sanitary ware characterized by being 0 to 20 wt%, it is possible to produce sanitary ware with high strength, small amount of fired deformation, and high thermal shock resistance. It became.

  According to a fifth aspect of the present invention, there is provided a ceramic body for sanitary ware, wherein the corundum is contained in a fired porcelain shale used as a raw material of the sanitary ware required ceramic body. This makes it possible to manufacture sanitary ware with superior thermal shock resistance at lower cost.

  Further, according to the invention described in claim 6, by providing a ceramic base for sanitary ware, characterized in that the unglazed bending strength is 100 MPa or more and the thermal shock resistance is 160 ° C. or more. In addition, it has become possible to manufacture lightweight sanitary ware with excellent thermal shock resistance without generation of kiln sharks.

  According to a seventh aspect of the present invention, there is provided the sanitary ware ceramic body according to claim 7, wherein the sanitary ware ceramic body has a firing deformation amount of 17 mm or less in the firing process in the firing process of the sanitary ware ceramic body manufacturing process. By providing, it became possible to manufacture sanitary ware with a thin and sharp shape.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect of enabling a thin-walled lightweight sanitary ware by providing the sanitary ware element ground which is high intensity | strength, has small baking deformation, and was excellent in the thermal shock resistance, and its manufacturing method.

The ceramic body for sanitary ware according to the present invention comprises a glass phase and a crystal phase. The main component of the crystal phase is quartz, which is characterized by one or less quartz particles of 80 μm or more per 1 mm ² . When the existence probability of quartz particles of 80 μm or more exceeds 1 per 1 mm ² as the coarse particles of the quartz particles, there is a problem that the substrate strength is lowered. The preferable number of quartz particles of 80 μm or more per 1 mm ² is not limited and may be zero, but industrially, it is 0.01 or less because of cost increase.

The existence probability of coarse quartz particles defined here is determined by observing 10 or more screens of the cut surface of the substrate with a microscope in a field of view of 1 mm ² or more and counting the number of quartz particles having a side of 80 μm or more. Shall. That is, if 100 microscopic fields having a size of 1 mm ² are observed on 100 screens and a total of 200 quartz particles of 80 μm or more are observed, the existence probability can be calculated to be ² per 1 mm ² .
Since the quartz particles are indefinite, the maximum distance is the size of the quartz particles. For example, if 90 μm × 10 μm rectangular particles are observed in the microscope field, they are also counted as particles of 80 μm or more.

  The water absorption rate of the ceramic body for sanitary ware in the present invention is preferably 3 wt% or less, more preferably 0.1 wt% or less. If the water absorption rate is higher than a preferable value, water absorption occurs in the environment where the sanitary ware is used, and frost damage occurs or a problem arises in contamination resistance. Although there is no lower limit to the preferred water absorption rate, industrially setting it to 0.001% or less causes a cost increase. In order to sinter with such a small water absorption rate, it is not preferable to use calcined clay such as chamotte, and it is necessary to adjust the amount of the flux component as described later.

The unglazed bending strength of the sanitary ware ceramic body in the present invention is preferably 100 MPa or more. When the bendingless bending strength is less than 100 MPa, it is not possible to secure sufficient strength for reducing the thickness and weight of sanitary ware. Although there is no upper limit to the preferred bending strength, it is difficult to produce economically those having 300 MPa or more industrially. As means for increasing the bending strength, the present invention employs means for reducing the coarse content of quartz particles as much as possible.

The composition of the sanitary ware body preferred in the present invention is a group consisting of Na ₂ O, K ₂ O, and Li ₂ O, with the composition of the main components being SiO ₂ : 45 to 69 wt%, Al ₂ O ₃ : 20 to 45 wt%. The sum of at least one component selected from the group consisting of CaO, MgO, BaO and at least one component selected from the group consisting of CaO, MgO, and BaO: 3 to 6 wt%, and the quartz and mullite as crystal phase main components, or Quartz, mullite, and corundum are included, the content of the quartz is 5 to 30 wt%, the content of the mullite is 10 to 30 wt%, and the content of the corundum is 0 to 20 wt%. When the ratio of SiO ₂ exceeds the preferable upper limit, it becomes impossible to prepare a sufficient amount of necessary components such as clay and flux, so that the plasticity of the substrate is lowered or the sintering is not sufficiently advanced. If the SiO ₂ ratio is less than the preferred lower limit, a sufficient amount of quartz can be added to the substrate, so that the amount of firing deformation becomes too large. When the ratio of Al ₂ O ₃ exceeds the preferable upper limit, the amount of corundum contained in the substrate becomes too large, and the substrate cost increases or the specific gravity becomes too large to reduce the weight. If the ratio of Al ₂ O ₃ is less than the preferred lower limit, the amount of clay will be too small, which will adversely affect the plasticity of the substrate during molding. When the sum of at least one component selected from the group consisting of Na ₂ O, K ₂ O, Li ₂ O and at least one component selected from the group consisting of CaO, MgO, BaO exceeds a preferred upper limit The firing deformation of the substrate becomes too large, and when the preferred lower limit is exceeded, the shrinkage is reduced. The preferred component of the crystal phase in the present invention is the above-mentioned quartz, and mullite precipitated from the glass phase is also essential. If quartz exceeds the preferred upper limit, the sinterability of the substrate will decrease, and if the preferred lower limit is exceeded, the firing deformation of the substrate will become too large. The amount of mullite has a correlation with the amount of clay. If the amount of mullite exceeds the preferable upper limit, the amount of drying shrinkage of the substrate becomes too large, and if the amount exceeds the preferable lower limit, the plasticity of the substrate becomes insufficient. The crystal phase component in the present invention may further contain corundum. Adding a large amount of corundum increases the strength but increases the cost and the specific gravity. Therefore, the corundum content is preferably 0 to 20 wt%, more preferably 0 to 10 wt%. It is preferably as small as possible as long as necessary strength can be ensured, and may be 0.

The structure of the sanitary ware base in the present invention is as described above, but the maximum characteristic of this base is high strength and excellent thermal shock resistance. In other words, in the prior art, it is effective to increase the strength of the substrate by suppressing the occurrence of microcracks by atomizing the quartz by atomizing the substrate, but this method reduces the thermal shock resistance of the substrate, so that the kiln shark It was said that the occurrence of this would be adversely affected. However, in the present invention, by suppressing the existence probability of quartz particles of 80 μm or more to 1 or less per 1 mm ² , the thermal shock resistance is simultaneously improved while maintaining the merit of high strength by suppressing the generation of microcracks as much as possible. I was able to.

  The preferred thermal shock resistance temperature of the sanitary ware body of the present invention is 160 ° C. or higher, and this thermal shock resistance temperature can be increased by reducing the existence probability of quartz particles of 80 μm or higher as much as possible. The measurement method / evaluation method of thermal shock resistance will be described in detail in the examples described later.

  As described above, this technology that enables both strength and thermal shock resistance, which have been considered to be conflicting elements, has been achieved with conventional sanitary ware that has a bending strength of 100 MPa or higher and a thermal shock resistance of 160 ° C or higher. Achieved high strength and high thermal shock resistance at an unacceptable high level, making it possible to produce thin and light sanitary ware.

Such sanitary ware for ceramic green body pottery stone, silica, silica sand, clay, corundum-containing raw material, a ceramic green body material selected from sintered flux material such as quartz particles in the matrix after firing per 1 mm ² 80 [mu] m A slurry prepared by dispersing and mixing and adjusting the particle size in water so that the number of the quartz particles is 1 or less is prepared, the slurry is cast-molded, the molded body is dried, and then applied to a necessary portion. It can manufacture by baking at -1300 degreeC. Porcelain stone, silica stone, silica sand, clay, sintered flux raw material, etc. are melted by removing the quartz contained in the raw material to form a glass phase, and mullite is precipitated from the glass phase. Further, most of the quartzite and quartz sand, and part of the ceramic stone, clay, and sintered flux raw material are made of quartz crystals, and some of the quartz crystals are dissolved in the glass phase. Therefore, the particle size of the quartz contained in the raw material does not match the particle size of the quartz contained in the fired product, and the quartz particles in the fired product are dissolved in the glass phase around the quartz particles in the raw material. The diameter is reduced, and the fine quartz particles in the raw material are completely dissolved in the glass phase.

  Therefore, the particle size control of the quartz particles must be performed by measuring the particle size of the quartz in the fired body in consideration of the firing conditions, not the particle size control in the raw material. As a means for reducing the coarse particle size of 80 μm or more as much as possible, first, when using a raw material containing quartz crystals such as porcelain stone, feldspar, clay and flux raw material, a brand free from coarse quartz as much as possible is selected. If the raw material containing coarse-grained quartz is made fine in the pulverization step, the overall average particle size becomes too fine, resulting in a decrease in the thermal shock resistance of the substrate.

  In addition, if the overall average particle size is too fine, there is a problem that the plasticity at the time of forming the substrate is lowered. A preferable average particle size of the slurry is 4 μm or more and 8 μm or less. In addition, a raw material containing a large amount of quartz serving as a coarse quartz source may be provided with a separate pulverization step and finely mixed, and then mixed with the slurry.

  In addition, the quartz content can be obtained not from the quartz content contained in porcelain stone, clay, flux raw material, etc., but from quartz sand whose particle size is controlled. However, since there are many expensive brands of porcelain stone, clay, and flux materials that do not contain quartz at all, it is necessary to consider their use in consideration of economy.

  Even when all the quartz content is taken from the silica sand whose particle size is controlled, the silica sand whose particle size is controlled may contain a coarse quartz content in a small part thereof. Therefore, it is a reliable method to remove coarse particles by sieving, even when using silica sand whose particle size is controlled for all quartz, and when taking quartz from porcelain stone, silica stone, clay, and flux materials. . This is an effective means because most of the coarse particles in the slurry are quartz, but as mentioned above, the quartz particle size in the raw material and the quartz particle size in the fired body are different, and In particular, the coarse-grained quartz produced when crushing ceramics has a high aspect ratio and must be stopped. For example, if a sieve having an aperture of 80 μm or less is used, the periphery of the quartz particles dissolves in the glass phase during firing, and the diameter becomes small. Therefore, it is not the case that particles of 80 μm or more are absolutely not present in the fired body. Particles having a high aspect ratio, for example, 100 μm × 30 μm × 30 μm, easily pass through the 80 μm sieve mesh. In general, it is industrially difficult to pass the slurry through a sieve having a small sieve opening, because the sieve is clogged. A preferable sieve opening is 90 μm or more.

  Also preferred as the corundum-containing raw material, which is a raw material for the sanitary ware base material in the present invention, is a calcined clay shale. The calcined porphyry shale contains corundum crystals and mullite crystals as main components, and the thermal shock resistance is improved, although the strength is slightly reduced as compared with the case where alumina is added alone as corundum crystals. Since the corundum crystal used as the raw material hardly dissolves in the glass phase unlike the case of the quartz crystal, the particle crystal diameter in the raw material almost becomes the crystal diameter in the fired body. The average system of corundum particles is preferably 2 μm to 20 μm. If it exceeds 20 μm, the effect of improving the strength is not sufficient, and if it is smaller than 2 μm, the dispersibility becomes worse.

The minerals other than quartz and corundum constituting the raw material used in the present invention are listed below. Clay minerals such as sericite, kaolinite, pyrophyllite, dickite and halloysite are added to improve plasticity during molding and are the main constituents of clay and ceramic stone. Examples of the flux minerals include potassium feldspar, soda feldspar, calcium feldspar, dolomite, wollastonite, nepheline sianite, talc, petalite, calcite, magnesite, barium carbonate, and the like. These are Na ₂ O, K _2. It is a mineral serving as a flux component source that acts as a sintering aid such as O, Li ₂ O, CaO, MgO, BaO.

  Further, the method for forming a sanitary ware base material according to the present invention is cast molding using a slurry. In order to produce the slurry, it is necessary to disperse the raw material powder in water. Used. As the peptizer, water glass, sodium carbonate, sodium humate, sodium polyacrylate, acrylic acid oligomer ammonium salt, or the like can be used. In addition, when the strength of the molded body is particularly necessary, a binder can be added to the slurry. Various emulsion binders, sodium carboxymethyl cellulose, polyvinyl alcohol, dextrin, gum arabic, tragagant rubber, methyl cellulose, peptone, water-soluble starch, colloidal silica A binder such as can be used.

  The slurry may be prepared by wet pulverization using a cylinder mill, bead mill or the like, or by blender mixing using a raw material whose particle size is controlled, but it is necessary to manage the coarse quartz as described above. The prepared slurry is formed using gypsum casting or pressure casting, and then becomes a sanitary ware through the steps of the prior art of drying, glazing, and firing at a temperature of 1100 to 1300 ° C.

  The preferred amount of firing deformation in this firing step is 17 mm or less, and if it exceeds the preferred range, it will be difficult to reduce the thickness and weight sufficiently. Although there is no lower limit for the preferred amount of firing deformation, it is difficult to make the amount of firing deformation 5 mm or less industrially. In addition, the measuring method of the amount of baking deformation said here is explained in full detail in an Example. As described above, in order to suppress the amount of firing deformation to be small, it is necessary to allow sintering to proceed even if the amount of flux components is suppressed by reducing the average particle size as described above. The thermal shock resistance deteriorates as the value is reduced. Therefore, by reducing the existence probability of coarse-grained quartz particles, which is a technology in the present invention, it becomes possible to control the three values of strength, fired deformation, and thermal shock resistance to values suitable for thin-walled lightweight sanitary ware. It is possible to reduce the thickness and weight by 20-30% from the current sanitary ware.

Examples of the present invention will be described below.
Table 1 shows the chemical composition of the raw materials used in the examples. These are all natural raw materials, and the chemical compositions shown are representative values. The minerals contained are estimated by XRD quantitative analysis, and there is an error from the sum of the pure chemical composition of each mineral.

  Porcelain stones are sericite-type and kaolinite-type low-purity and high-purity ones. High-purity ones are sericite and kaolinite, which are almost pure clay minerals. Contains minutes. Sasame clay and feldspar also contain quartz. The calcined porphyry shale is obtained by calcining natural porphyry shale shale to a composition of about 80 wt% corundum, about 10 wt% mullite, and about 10 wt% glass component. The kaolin mineral includes not only kaolinite but also daykite, pyrophyllite and halloysite, and the total amount of kaolin mineral and sericite is the amount of clay mineral contained in all raw materials.

Tables 2 and 3 show the raw materials used for the bases according to the comparative examples and examples in the present invention, the contained composition minerals in the raw materials, the raw material average particle system, the firing temperature, the base composition, the amount of coarse quartz, and the physical properties of the bases. Each display method, preparation method, measurement method, and evaluation method are as follows.
The presence / absence of raw material preparation in Tables 2 and 3 indicates that the raw materials shown in Table 1 were used, and when the respective preparation ratios were summed, the ratio of the mineral composition in the raw materials shown in Tables 2 and 3 was obtained. Yes.
Water glass as a peptizer was added to the raw materials of each composition so that the viscosity of water and peptizer was in the range of 200-400 CP, and pulverized with a ball mill to prepare a slurry. The volume concentration of the slurry is 49-52 vol% in terms of the volume concentration of the powder in the slurry. The average particle size of the raw material in the slurry was measured with a laser scattering type particle size distribution measuring device (Microtrack MT-3000 manufactured by Nikkiso Co., Ltd.) and displayed as a particle size with a cumulative volume of 50%.

Next, this slurry was poured into a gypsum mold to prepare a test piece having a predetermined shape to be described later. Each test piece was baked after drying at 1200 ° C. for 30 minutes.
The chemical composition of each substrate was determined by XRF analysis of the calcined substrate, and the amount of each oxide was quantified. In the XRD analysis of each calcined substrate, peaks other than quartz, mullite, and corundum could not be observed, and the corundum peaks could only be observed when corundum was added as a raw material. Therefore, XRD analysis was used to quantify mullite, quartz, and corundum in the fired substrate. The amount of crystal phase in the base composition was expressed as the total amount of mullite, quartz and corundum, and the amount of glass phase was expressed as 100% minus the amount of crystal phase. Moreover, the amount of calcination flux was displayed as the total amount of Na ₂ O, K ₂ O, CaO, and MgO in the chemical composition of the substrate.

The amount of coarse-grained quartz was determined as follows. The cut surface of the test piece was wrapped and immersed in a 0.5 wt% hydrofluoric acid solution for 1 hour. After washing and drying, the sample was observed for quartz particles using a confocal laser microscope (Olympus OLS1100). The observation conditions were 10 times the objective lens and the field of view range was 1.28 mm × 0.96 mm (1.23 mm ² ). FIG. 1 shows an observation example of Example 2, and FIG. The matrix phase that appears black is the glass phase, and the white particles are the quartz crystal particles. The mullite crystal particles are covered with the glass phase and cannot be observed in this photograph, but can be observed when the glass phase is dissolved by stricter etching conditions with hydrofluoric acid. The white particles in Example 2 include corundum particles contained in a trace amount, but all the corundum particles are finely pulverized to a particle size of 30 μm or less. In each field of view, I counted the number of quartz particles with a maximum diameter of 80 μm or more. Then, 10 or more arbitrary positions were measured for each sample, and the number of quartz particles of 80 μm or more per 1 mm ² was calculated from the average.

Of the physical properties, the water absorption rate was evaluated by the rate of weight increase when a completely dried test piece was boiled for 2 hours and allowed to stand for 24 hours. The firing shrinkage was determined from the change in the length of the test piece in the radial direction before and after firing. The strength was measured by a three-point bending method using a test piece of φ13 × 130 mm under a span of 100 mm and a crosshead speed of 2.5 mm / min. Regarding the amount of firing deformation, an unfired test piece having a width of 30 mm, a thickness of 15 mm, and a length of 260 mm was supported with a span of 200 mm during firing, and the amount of deflection after firing and the thickness of the test piece were measured. Since the amount of deflection at this time is inversely proportional to the square of the thickness of the test piece after firing, the amount of deflection converted when the thickness is 10 mm is defined as the amount of firing deformation in the following equation.
Firing deformation amount = amount of deflection measurements × (thickness after firing of the test piece) ^{2/10 2}

The thermal shock resistance was evaluated by holding a fired test piece having a width of 25 × thickness of 10 × length of 110 mm at a predetermined temperature for 3 hours, and then cooling it by placing it in water to check for the occurrence of cracks. The rapid cooling temperature was increased by 10 ° C., and the maximum temperature difference at which no cracks occurred was shown as thermal shock resistance.

  The comparative example 1 is a general base material conventionally used for the production of sanitary ware. In such a substrate, when a large complex shape product such as sanitary ware is prototyped with a thin wall, the deformation of the product is large and it is not suitable for production.

  Comparative Example 2 is a prior art substrate in which the substrate is strengthened and firing deformation is reduced by atomizing Comparative Example 1. In such a substrate, the thermal shock resistance is greatly reduced, so that it is easy to generate kiln sharks, and the substrate is poor in plasticity, the workability is deteriorated, and the production of dry cracks is large. There is.

  Comparative Example 3 is a substrate from which coarse particles are removed by sieving with an opening of 90 μm using high-purity sericite porcelain, high-purity kaolin porcelain and high-purity quartz particles. In this substrate, since the quartz particles are coarse, coarse quartz particles with a large aspect ratio cannot be removed even through sieving, and because the average particle size is also coarse, the strength is low and the firing deformation is large. It is unsuitable for making.

  The comparative example 4 is a base material in which a base clay is added to the base material based on the mixing ratio of the comparative example 1 to increase the strength of the base material. In this substrate, the strength is improved by the addition effect of corundum, but the strength to obtain the light weight effect due to thinning is not obtained due to the presence of coarse quartz, and the average particle size is also coarse, so the firing deformation is large. .

  Comparative Example 5 is obtained by atomizing Comparative Example 1 in the same manner as Comparative Example 2, but the particle size is designed to be slightly coarse so that the plasticity of the substrate does not deteriorate. In this case, the effect of improving the strength is not obtained so much.

  Comparative Example 6 is a substrate obtained by removing coarse quartz by passing through a sieve having an opening of 90 μm. However, since the average particle size is coarse, the coarse quartz cannot be sufficiently removed, and the effect of improving the strength is not obtained so much. .

  In Comparative Example 7, high purity quartz contained in the base material of Comparative Example 3 was pulverized and atomized in advance before preparation to prepare a base material. In this substrate, the strength is slightly improved, but a high strength of 100 Mpa or more is not obtained.

As described above, the bases of all the comparative examples have a probability of existence of coarse quartz of 80 microns or more per 3 mm ² and have low thermal shock resistance. Moreover, it is not suitable for thinning sanitary ware by comprehensively evaluating the thermal shock resistance, strength, and amount of fire deformation.

  Example 1 is a base material obtained by removing coarse-grained quartz through a sieve having an opening of 90 μm, based on Comparative Example 7.

In Examples 2 to 4, a clay shale is added as a raw material.
In Example 2, Comparative Example 3 was atomized and added with porphyry shale, but the particle size was adjusted so as not to be too fine so as not to deteriorate the plasticity of the substrate.
Example 3 is a substrate obtained by further removing coarse quartz from Example 2 by passing through a sieve having an opening of 90 μm.
Example 4 does not use the quartz contained in the porcelain stone of Example 3, but uses high-purity sericite porcelain, high-purity kaolin porcelain, and high-purity quartz particles atomized by pulverization, and further has an opening of 90 μm. This is a substrate from which coarse quartz is removed by sieving.

  Corundum contained in the porphyry shale strengthens the substrate and is effective in improving thermal shock resistance, but when combined with the removal of coarse-grained quartz, the amount of corundum leading to increased cost and specific gravity is less than 10 wt% The effect of strengthening the substrate by corundum can be efficiently extracted.

As described above, in the substrates of all the examples, the existence probability of coarse quartz of 80 μm or more is 1 or less per 1 mm ² and exhibits high thermal shock resistance. Moreover, it is a base suitable for thinning sanitary ware by comprehensively evaluating the thermal shock resistance, strength, and amount of fired deformation, and can reduce the thickness and weight by 20-30% from the current sanitary ware.

The ceramic body for sanitary ware according to the present invention has a high firing strength, a small amount of thermal deformation during firing, and is excellent in thermal shock resistance. Therefore, it can be used to make sanitary ware thinner and lighter.

It is a microscope picture which shows the fine structure of the sanitary ware body of this invention. It is a microscope picture which shows the microstructure of the conventional sanitary ware body.

Claims (7)

A ceramic body for sanitary ware comprising a glass phase and a crystal phase, wherein the main component of the crystal phase is quartz, and the cut surface of the sanitary ware ceramic body is 1 mm ² or more using a laser microscope (10x objective lens). A ceramic body for sanitary ware, wherein the existence probability of quartz particles of 80 μm or more is 1 or less per 1 mm ² when 10 or more screens are observed with a visual field of size of 1 mm ² .   The ceramic body for sanitary ware according to claim 1, wherein a water absorption rate of the sanitary ware ceramic body is 3 wt% or less.   3. The sanitary ware ceramic body according to claim 1 or 2, wherein the sanitary ware ceramic body has an unglazed bending strength of 100 MPa or more. The sanitary ware for porcelain composition of the main component of the matrix constituting the the _{SiO 2: 45~69wt%, Al 2} O 3: a 20 to 45 _wt%, selected from the group consisting of _{Na 2 O, K 2 O,} Li 2 O And at least one component selected from the group consisting of CaO, MgO, and BaO: 3 to 6 wt%, and the quartz and mullite as the main component of the crystal phase, or quartz It contains mullite and corundum, the quartz content is 5 to 30 wt%, the mullite content is 10 to 30 wt%, and the corundum content is 0 to 20 wt%. Item 4. The ceramic body for sanitary ware according to any one of Items 1 to 3.   5. The ceramic body for sanitary ware according to claim 4, wherein the corundum is contained in a fired porcelain shale used as a raw material for the sanitary ware required ceramic body.   A ceramic body for sanitary ware, characterized by a bending strength of 100 MPa or more and a thermal shock resistance of 160 ° C or more.   The ceramic body for sanitary ware according to any one of claims 1 to 6, wherein an amount of firing deformation by a solid test piece in a firing process in the manufacturing process of the ceramic body for sanitary ware is 17 mm or less. .