JP2023048031A - Ceramic sanitary ware - Google Patents

Abstract

To provide a ceramic sanitary ware having low water absorption, low softening deformation, low firing shrinkage, high strength, cold crack resistance, and light weight.SOLUTION: A ceramic sanitary ware has a wrought-ground ceramic base and a glaze layer, and a portion of the base is exposed to the outside without a glaze layer. The base contains (A) anorthosite and (B) an alkali component; the amount of the alkali component is 5 to 10 wt% of the base in terms of oxide (A2O); and the closed porosity of the base is 12 to 15 vol%.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to sanitary ware used in toilet bowls, wash basins and the like.

Since sanitary ware is considerably heavier than tableware, if porcelain with a large amount of glass is used, deformation due to its own weight during firing becomes very large, making manufacturing difficult. On the other hand, if pottery with less glass and more crystals is used, the non-glazed portion will absorb water. As a result, problems such as absorption of sewage and damage due to frost damage may occur. Therefore, sanitary ware uses a fusible ceramic base that suppresses deformation during firing and minimizes water absorption, which is between porcelain and earthenware.

That is, at present, sanitary ware is generally provided with a ceramic body of liquefied texture and a glaze layer. It is a structure that consists of For example, in the case of a toilet bowl, due to such a structure, it hardly deforms under a seating load, maintains sufficient strength, and maintains hygienic properties because the surface is less likely to be damaged. In addition, since the pottery base, which is a fused base material, is densified to reduce water absorption as much as possible, problems due to water absorption at exposed portions are prevented.

Sanitary ware is relatively large and has a complicated shape among ceramic products, so it has a thick structure in order to maintain the strength of the product. The bending strength of the conventional substrate is 50 to 80 MPa, and this strength requires a thickness of about 7 to 12 mm for the product. As a result, the weight of the product has increased, and there has been a demand for lighter sanitary ware in terms of transportation, construction, and upsizing.

In addition, since sanitary ware is large in size, the self-weight of the molded body is large, and is significantly affected by softening and deformation due to the influence of gravity during firing. Furthermore, sanitary ware needs to be densely baked to reduce water absorption as much as possible. At that time, the air bubbles inside the base body move to the outside, so that the firing shrinkage increases. As a countermeasure against such softening deformation and sintering shrinkage, a process called warikake, in which deformation due to sintering is predicted and a compact larger than the intended shape is produced, is generally performed. However, it is difficult to suppress variations in the amount of softening deformation due to variations in the firing temperature, and in some cases correction work such as polishing is required. Moreover, when the firing shrinkage rate is large, it is difficult to reproduce the linearity in a large area by splitting. Furthermore, in recent years, there has been a tendency to increase the size of products, and in the case of increasing the size of the molded body by splitting, it is necessary to increase the size of the molding equipment, which cannot be handled by the existing equipment. In other words, sanitary ware is greatly restricted in terms of design and productivity due to softening deformation and firing shrinkage.

In addition, due to the large and complicated structure, a large temperature difference is likely to occur inside the fired body when it comes out of the kiln, and this temperature difference causes stress due to the difference in thermal expansion inside the product. When this generated stress exceeds the base strength, a defect called cold cracking occurs. Strength is an important design factor for sanitary ware that is subjected to repeated loads due to seating, etc. Cold cracks, which reduce strength, are a fatal problem. Therefore, there has been a demand for sanitary ware that is resistant to cold cracking and that can suppress softening deformation and firing shrinkage while ensuring strength and low water absorption.

Conventionally, techniques have been proposed to reduce product weight while maintaining bending strength above the above level and reducing water absorption.

For example, Japanese Patent Application Laid-Open No. 2000-319061 (Patent Document 1) describes a ceramic ware consisting of a base and a glaze layer formed on a necessary portion thereon, wherein the central part of the base is a water-absorbing pottery base. It is disclosed that the formed body is impregnated with an alkaline component and then fired so that at least a portion of the surface of the base where the glaze layer is not formed has lower water absorption than the central portion of the base. It is

Japanese Patent Application Laid-Open No. 2002-68821 (Patent Document 2) discloses a sanitary ware comprising a ceramic base and a glaze layer formed on a necessary portion of the base, wherein the main component constituting the base is SiO ₂ : 50 to 75 wt%, Al ₂ O ₃ : 20 to 45 wt%, Na ₂ O: 0.5 wt% or more, and at least one selected from the group consisting of Na ₂ O, Li ₂ O, and K ₂ O The sum of the seed component and at least one component selected from the group consisting of CaO, MgO, BaO, and BeO is 2 to 6 wt%, and the crystal is selected from quartz, cristobalite, mullite, and corundum. This document discloses a sanitary ware characterized by containing at least one or more kinds of crystals and having a total amount of crystals of 10 to 60 wt % with respect to 100 of the entire base. Although this technology suppresses the amount of softening deformation, it cannot suppress firing shrinkage.

Japanese Patent Application Laid-Open No. 2001-348263 (Patent Document 3) discloses a sanitary ware comprising a ceramic base and a glaze layer formed on a necessary portion of the base, wherein the base contains mullite and quartz as main components. A body containing a crystalline phase, a glass phase containing SiO ₂ and Al ₂ O ₃ as main components, and a crystalline phase made of a mineral selected from cristobalite, andalusite, sillimanite, kyanite, and corundum, if necessary. , the main components of the substrate are SiO ₂ : 50 to 65 wt%, Al ₂ O ₃ : 30 to 45 wt%, alkali oxides 0.1 to 2 wt%, divalent metal oxides 0.1 to 10 wt%, Disclosed is a sanitary ware characterized by containing at least a CaO component as a divalent metal oxide component, and having CaO component segregated portions in which the CaO component is segregated in the base. This technology suppresses firing shrinkage and softening deformation, but does not achieve low water absorption.

Japanese Patent Application Laid-Open No. 2002-68825 (Patent Document 4) discloses a framework-forming material represented by pottery stone, silica stone, Rouseki, chamotte, vando shale, and kaolin, and a plastic raw material represented by Gairome clay, Kibushi clay, and kaolin. , calcium raw materials such as wollastonite, limestone, and anorthite, and in some cases, ceramic raw materials composed of sintering aid raw materials such as feldspar and dolomite, to obtain a molding base, and if necessary, In a sanitary ware body that can be produced by a method that includes a glaze application step of applying a glaze to a necessary part with a sintering step and a firing step, the filling rate of the molding body in the molding step is 68% by volume or more, and the main component of the body has a composition of SiO ₂ : 45 to 70% by weight, Al ₂ O ₃ : 25 to 50% by weight, and other compositional components selected from the group consisting of Na ₂ O, K ₂ O, and Li ₂ O. containing at least one alkali metal oxide and/or at least one alkaline earth metal oxide selected from the group consisting of CaO, MgO, BaO and BeO, and from Na ₂ O, K ₂ O and Li ₂ O The total amount of at least one alkali metal oxide selected from the group consisting of 2% by weight or less, and at least one alkali metal oxide selected from the group consisting of Na ₂ O, K ₂ O and Li ₂ O and at least one alkaline earth metal oxide selected from the group consisting of CaO, MgO, BaO, and BeO is 10% by weight or less, and contains at least a CaO component as an alkaline earth metal oxide component Disclosed is a ceramic ware characterized by:

WO97/26223 (Patent Document 5) discloses that in a ceramic body composed of a crystal phase and a glass phase and containing alkali oxides and alkaline earth oxides in the glass phase, the total amount of the alkali oxides and alkaline earth oxides is A ceramic body is disclosed which is characterized by a molar ratio of alkaline earth oxides to 30 mol % or more.
Although this technology reduces the amount of firing deformation, it does not achieve both low water absorption and weight reduction.

Japanese Patent Application Laid-Open No. 2001-287981 (Patent Document 6) discloses a sanitary ware comprising a ceramic base and a glaze layer formed on a necessary portion of the base, wherein the composition of the main component constituting the base is SiO: 45 to 70% by weight, Al ₂ O ₃ : 25 to 50% by weight, and the matrix further contains alkali metal oxides and at least one alkali selected from the group consisting of CaO, MgO, BaO, and BeO. The total content of earth metal oxides is 6% by weight or less, the amount of alkali metal oxides in the base is 2% by weight or less, Na ₂ O as an essential component of the alkali metal oxides, and an optional component and containing 20% by weight or more _{of Na 2 O} with respect to the total amount of Na ₂ O and K ₂ O.

Japanese Patent Application Laid-Open No. 2002-255630 (Patent Document 7) describes a sanitary ware comprising a ceramic base and a glaze layer formed on a necessary portion of the base, wherein the composition of the main component constituting the base is SiO ₂ : 45 to 70% by weight, Al ₂ O ₃ : 25 to 50% by weight, and the matrix further contains 10% by weight or less of alkali metal oxides and alkaline earth metal oxides in total, The amount of alkali metal oxide in the base material is 2% by weight or less, and CaO and MgO are contained as essential components of the alkaline earth metal oxide, and MgO is present with respect to the total amount of CaO and MgO. A sanitary ware characterized by a content of 20% by weight or more is disclosed.

Japanese Patent Application Laid-Open No. 2002-80266 (Patent Document 8) discloses a sanitary ware comprising a ceramic base and a glaze layer formed on a necessary portion of the base, wherein the base mainly contains mullite and quartz. A body containing a crystalline phase, a glass phase containing SiO ₂ and Al ₂ O ₃ as main components, and a crystalline phase made of a mineral selected from cristobalite, andalusite, sillimanite, kyanite, and corundum, if necessary. , the main components of the substrate are SiO ₂ : 50 to 65 wt%, Al ₂ O ₃ : 30 to 45 wt%, alkali oxides 0.1 to 2 wt%, divalent metal oxides 0.1 to 10 wt%, and As a divalent metal oxide component, at least a CaO component is contained, CaO component segregation parts in which the CaO component is segregated are scattered in the base material, and as the base material, a fibrous material having an aspect ratio of 10 or more Sanitary ware characterized by using wollastonite is disclosed. This technology suppresses firing shrinkage and achieves both high strength and weight reduction, but it has not been able to achieve low water absorption.

Japanese Patent Application Laid-Open No. 2011-162376 (Patent Document 9) discloses a fired body consisting of a crystal phase containing at least mullite, quartz, and anorthite as main components and a glass phase containing SiO ₂ and Al ₂ O ₃ as main components. It discloses a lightweight pottery characterized by having a large number of independent pores surrounded by anorthite in the fired body and having a bulk density of 2.0 to 2.4 g/cm3.

Furthermore, Japanese Patent Application Laid-Open No. 2002-97068 (Patent Document 10), Japanese Patent Application Laid-Open No. 2002-114565 (Patent Document 11), and Japanese Patent Application Laid-Open No. 2002-114566 (Patent Document 12) maintain the bending strength while reducing the product weight. is disclosed.

On the other hand, as a glaze for sanitary ware, for example, the glaze described in WO99/61392 (Patent Document 13) is used.

JP 2000-319061 JP 2002-68821 JP 2001-348263 JP 2002-68825 WO97/26223 JP 2001-287981 JP 2002-255630 Japanese Patent Application Laid-Open No. 2002-80266 JP 2011-162376 JP 2002-97068 JP 2002-114565 Japanese Patent Application Laid-Open No. 2002-114566 WO99/61392 Japanese Patent Laid-Open No. 4-2679

For sanitary ware, there is still a demand for technology that can reduce product weight while maintaining strength while ensuring low water absorption, suppress firing shrinkage and softening deformation, and be resistant to cold cracking.

An object of the present invention is to provide a sanitary ware that can combine low water absorption, light weight, low firing shrinkage, low softening deformation, high strength and resistance to cold cracking.

The inventors of the present invention have recently found that the fused material has low water absorption, light weight, low firing shrinkage, low softening deformation, and high strength due to the composition, which is difficult to say as an appropriate composition for sanitary ware according to conventional knowledge. It was found that a sanitary ware having both cold cracking resistance and cold cracking resistance can be realized. The present invention is based on such findings.

And the sanitary ware according to the present invention is
A sanitary ware comprising a fusible ceramic base and a glaze layer, wherein a part of the base is exposed to the outside without the glaze layer,
The base material is
(A) anorthite;
(B) containing an alkaline component,
Here, the amount of the alkali component is 5 to 10% by weight in terms of oxide (A ₂ O) with respect to the base, and the closed porosity of the base is 12 to 15% by volume. It is something to do.

Sanitary ware and substrate In the present specification, "sanitary ware" means toilets, washbasins, and pottery products used around them, specifically, toilet bowls, urinals, tanks, perforated plates (sana), It means washbasin, washbasin, etc. The sanitary ware according to the present invention has the material described in JIS A5207:2019, "7.1 Types of materials", and satisfies the characteristics described in "7.2 Ceramic quality". It is preferable to be

The sanitary ware according to the present invention is basically a fused ceramic body. As used herein, the term "melting green earthenware body" has its normal meaning as understood in the art for sanitary ware, and thus the term "melting green earthenware substrate" as the substrate for sanitary ware according to the present invention. "Porcelain body" is to be understood in its ordinary sense, except that it comprises features according to the invention as described below.

In the sanitary ware according to the present invention, the "dissolvable ceramic body" contains (A) anorthite and (B) an alkali component, and the amount of this alkali component is converted to oxide (A ₂ O), and the base material is 5 to 10% by weight, preferably 5 to 8% by weight, more preferably 5 to 7% by weight. Here, the alkaline components are preferably Li, Na and K, and the oxides thereof are _Li2O , _Na2O and _K2O .

The sanitary ware body according to the invention is further characterized by its closed porosity. As used herein, the term “closed pores” means pores that are present inside the base material and are not connected to the outside air. The closed porosity is 12 to 15% by volume.

According to conventional knowledge, in large-sized ceramic products such as sanitary ware, the amount of alkaline component in the above range is disadvantageous in terms of product strength and deformation during firing. is understood. However, in the matrix in which such an alkali component, which is considered to be a large amount, coexists with (A) anorthite, low water absorption, low firing shrinkage, and low softening deformation can be realized. Furthermore, by controlling the porosity, it is possible to achieve both high strength and resistance to cold cracking, making it possible to reduce the weight of the product.

According to a preferred embodiment of the invention, the sanitary ware substrate according to the invention is also characterized by its water absorption. In the present specification, it is preferable that the water absorption obtained by the method for measuring "water absorption" described later is less than 2%.

According to a preferred embodiment of the invention, the sanitary ware body according to the invention is also characterized by its resistance to cold cracking. In the present specification, the cold cracking resistance obtained according to the measuring method of "cold cracking resistance" described later is preferably 120° C. or higher. In the present invention, the measurement of the resistance to cold cracking assumes the temperature at which cold cracking does not occur in all products under the condition that the product temperature at the exit of the kiln and the outside air temperature cause the most thermal load on the product. In addition, "thermal shock resistance", which will be described later in this specification, assumes the probability that a product will break at a specific temperature due to deterioration due to repeated thermal stress under various usage environments.

In the present invention, it is not clear why sanitary ware having low water absorbency, low softening deformation, low firing shrinkage, high strength, and resistance to cold cracking can be achieved. theory is possible. This theory is only a hypothesis, and the present invention is not bound by this theory.

As one of the theories, the following theory is conceivable, in which the pores generated when anorthite is generated at 900° C. to 1000° C. in the matrix are maintained up to the maximum firing temperature, and then the open pores can be blocked.

When the temperature of the fused mass containing kaolin is increased, first, metakaolin is produced by the dehydration reaction of kaolin. When limestone is blended as a base material, metakaolin reacts with limestone at 900 to 1000° C. to form anorthite (CaAl ₂ Si ₂ O ₈ ).
_{Al2O3.2SiO2 + CaCO3-} > _{CaAl2Si2O8 + CO2 ( 1} )
At this time, the portion where the limestone is consumed becomes pores, and anorthite is generated around the pores.

In the case of a normal sanitary ware base, metakaolin decomposes at 1000°C or higher to produce mullite and _SiO2 glass. Accordingly, the amount of closed pores may decrease and the flux component at the maximum temperature may increase.
_{3 ( Al2O3.2SiO2} ) _{→ 3Al2O3.2SiO2} + _4SiO2 ( ₂ )

However, due to the consumption of metakaolin in the anorthite formation reaction (reaction formula (1)) that occurs at a lower temperature during the heating, reaction formula (2) does not occur and mullite and _SiO2 glasses cannot be formed. It is thought that the pores generated by the anorthite formation reaction tend to remain as they are.

In this way, the pore volume is maximized up to the highest firing temperature of 1100-1200° C. where the melting reaction takes place, and the melting reaction reduces the viscosity of a relatively small amount of glass with reduced mass gain during heating to the high alkaline component. It is considered that the open pores could be reliably closed by lowering the viscosity and improving the fluidity. When glass is produced from feldspar in the melting reaction, the space left in the place where feldspar existed is fixed by the surrounding anorthite. Firing shrinkage can be suppressed. In addition, since the anorthite serves as a skeleton and supports the entire substrate, even glass with high fluidity is less susceptible to softening deformation. As a result, open pores can be blocked and a large number of closed pores can be left, and it is considered that excellent low water absorption, low softening deformation property and low firing shrinkage property were realized. In addition, the more closed pores, the more weight can be reduced, but since closed pores become the starting points of cracks, if the ratio of closed pores to the base material is large, it leads to a decrease in strength and an increase in the occurrence of cold cracks. However, by controlling the closed porosity, it is possible to realize a light weight, high strength, and cold crack resistant material.

A raw material containing calcium (Ca), such as wollastonite, can be used instead of limestone as a raw material that contributes to the formation of anorthite. In the present invention, the raw material containing calcium is at least one selected from the group consisting of limestone, wollastonite, dolomite, and apatite, preferably limestone, wollastonite, or both. These calcium-containing raw materials react with metakaolin (Al ₂ O ₃ .2SiO ₂ ) at 900 to 1000° C. to form anorthite.

When wollastonite is used as a raw material containing calcium, anorthite is thought to be produced by the reaction of the following formula (reaction formula (3)).
_{Al2O3.2SiO2 + CaSiO3-} > _{CaAl2Si2O8 + SiO2 ( 3} )
In the reaction of reaction formula (3) for anorthite formation, since CO ₂ gas is not generated, there is no increase in pores, and the density change during the firing process is small. In addition, since surplus SiO ₂ glass is produced in the reaction of reaction formula (3), this surplus SiO ₂ glass, together with the glass produced in the subsequent melting reaction, contributes to clogging the open pores. That is, when wollastonite is used as a raw material containing calcium, the amount of closed pores in the fired body is smaller than when limestone is used, but the deformation accompanying firing can be reduced. It is advantageous in many respects.

According to a preferred embodiment of the present invention, the amount of anorthite in the matrix is preferably 10-45% by weight, more preferably 10-31% by weight, even more preferably 10-25% by weight. The amount of anorthite can be obtained by performing Rietveld analysis on the X-ray diffraction pattern obtained by the powder analysis method and estimating the abundance of each crystal phase from the determined scale factor. A detailed method for quantifying anorthite is as described in Examples below.

According to a preferred embodiment of the present invention, the amount of the alkaline component in terms of oxide is 5 to 10% by weight, more preferably 5 to 9% by weight, and still more preferably 5 to 8% by weight, relative to the substrate. is. Further, the closed porosity is more preferably in the range of 12 to 15% by volume. Also, the water absorption is preferably less than 1%.

Further, according to a preferred embodiment of the present invention, the sanitary ware base contains 3 to 10% by weight, preferably 3 to 9% by weight, more preferably 3 to 7% by weight of calcium in terms of oxide (CaO). % by weight.

(C) Component: Aggregate The sanitary ware base material according to the present invention may contain an aggregate component from the viewpoint of its strength. As the aggregate component, it is possible to use a component that is usually added to a fused ceramic body, does not react during firing, suppresses shrinkage or softening deformation during firing, or affects the strength of the fired body.

According to a preferred embodiment of the present invention, the aggregate component, that is, component (C), contains at least one selected from the group consisting of corundum, chamotte, quartz, hollow silica, hollow alumina, zirconia, zircon, cordierite, and mullite. preferably.

In the present invention, the following advantages are expected to be obtained by using these aggregate components. That is, as described above, when metakaolin is consumed in the anorthite production reaction (reaction formula (1)) and a relatively large amount of anorthite is produced, there is a possibility that a large amount of shrinkage will occur in that reaction temperature range. . If this shrinkage occurs, it will spoil the matching with the glaze. Here, it was found that the above aggregate is a material that does not participate in the above reaction formula (1) and does not easily increase the flux component in the melting reaction. Therefore, the use of these aggregates is advantageous from the viewpoint of low water absorption and weight reduction. Furthermore, according to a preferred embodiment of the present invention, sanitary ware with excellent thermal shock resistance can be obtained by using these aggregate components.

In the present invention, the shape and components of the aggregate component can be identified from the backscattered electron image of the polished surface of the sanitary ware by a scanning electron microscope (SEM) and the elemental mapping by energy dispersive X-ray analysis (EDX). can.

Raw material and composition of sanitary ware base The raw material for the sanitary ware base can be prepared from conventionally known raw materials in consideration of the composition. Specifically, silica sand, feldspar, limestone, wollastonite, clay, alumina, chamotte, and the like can be used. The composition of the base material of the sanitary ware according to the present invention is preferably as follows, and the raw materials for the base material are blended so as to have the following composition.
SiO ₂ 40-65 parts by weight Al ₂ O ₃ 20-50 parts by weight CaO 3-10 parts by weight MgO 0.1-1 parts by weight K ₂ O 3-6 parts by weight Na ₂ O 0.5-5 parts by weight Li ₂ O 0 to 2 parts by weight

Glaze layer Although the glaze layer of the sanitary ware according to the present invention is not limited, according to a preferred embodiment of the present invention, the composition of the glaze layer is preferably the composition shown below in terms of oxide.
SiO ₂ 55-80 parts by weight Al ₂ O ₃ 5-13 parts by weight Fe ₂ O ₃ 0.1-0.4 parts by weight CaO 8-17 parts by weight MgO 0.8-3.0 parts by weight ZnO 3-8 parts by weight Part K ₂ O 1-4 parts by weight Na ₂ O 0.5-2.5 parts by weight ZrO ₂ 0-15 parts by weight Pigment 0-20 parts by weight

The raw material for the glaze layer can be prepared from conventionally known raw materials in consideration of the composition. Examples include silica sand, feldspar, limestone, dolomite, alumina, zinc white, and zircon.

According to a preferred embodiment of the present invention, the sanitary ware base material and the glaze layer are combined so that there is no significant difference in deformation between the base material and the glaze layer after firing, and the shape or surface condition of the sanitary ware is not adversely affected. Preferably.

In this preferable combination, for example, the amount of deformation is within 5 mm in matching with the glaze in the examples described later. Further, according to another aspect of the present invention, it is preferable that the coefficient of linear expansion of the substrate is higher than that of the glaze by about 5×10 ⁻⁷ /K to 10×10 ⁻⁷ /K.

Manufacture of sanitary ware The sanitary ware according to the present invention can be obtained by casting the slurry prepared from the base material described above in a mold such as gypsum, drying it, glazing it, and firing it. In the present invention, as described above, the pores generated when the anorthite is generated are maintained up to the maximum firing temperature, and then the open pores are closed to leave a specific amount of closed pores in the base material, resulting in good low temperature. Since water absorption, low firing shrinkage, low softening deformation, high strength, resistance to cold cracking, and weight reduction can be achieved, it is preferable to determine the firing conditions so that these reactions and phenomena occur reliably. According to one aspect of the present invention, the firing is preferably carried out by increasing the temperature by about 200° C. per hour and maintaining the temperature at a maximum temperature of 1180 to 1200° C. for 2 hours.

The measurement methods of "water absorption", "closed porosity", "sintering shrinkage", "softening deformation", "flexural strength" and "cold crack resistance" defined in the present invention are as follows.

As a water absorption measurement sample, a sintered body molded or cut into a size of 7 mm×8 mm×70 mm is prepared. The sample is dried at 110° C. for 24 hours, and the sample weight is measured and taken as the dry weight. After that, the sample is placed in a container and deaerated for 20 minutes with a vacuum pump. Distilled water is poured into the container containing the sample while maintaining vacuum, and the sample is further degassed for 60 minutes. Open to the atmosphere, immerse the sample in water, remove the water on the sample surface with a cloth, etc., and measure the weight. Let this be the weight at the time of water absorption. The water absorption is calculated by the following formula [Equation 1].

Apparent density is obtained by the following formula [Formula 2] from the numerical values obtained for obtaining the closed porosity and water absorption.

Furthermore, the "true density" was measured as follows. That is, the fired body was pulverized to the extent that closed pores were not included, and the density of the powder was measured using water as a solvent and a pycnometer. This was taken as the “true density” of the substrate.

From the apparent density and true density obtained above, the closed porosity is defined by the following formula [Equation 3].

Firing Shrinkage Ratio A green body sample was prepared by cutting out a 7 mm×8 mm×70 mm size from the base material before firing. The length of the central portion of this molded body sample was measured. Next, this sample was fired, and the length of the central portion of the sample after firing was measured. The shrinkage ratio was calculated from the difference in the amount of shrinkage.

Amount of Softening Deformation A molded test piece with a width of 30 mm, a thickness of 10 mm, and a length of 250 mm is fired while being held at a span of 200 mm, and the amount of sagging at the center of the test piece after firing is measured. bottom. Since the magnitude of softening deformation is inversely proportional to the square of the thickness, the value converted to a thickness of 10 mm was used as the softening deformation amount.

Bending strength Bending strength was measured according to JIS A1509-4:2014. Specifically, it is as follows. As a rectangular parallelepiped sample, a sintered body molded or cut into a size of 7 mm×8 mm×70 mm was prepared. The 3-point bending strength of this sample was measured. The measurement conditions were a span of 50 mm and a crosshead speed of 0.5 mm/min.

A sintered body with a diameter of 14 mm×150 mm was prepared as a round bar sample. The 3-point bending strength of this sample was measured. The measurement conditions were a span of 100 mm and a crosshead speed of 2.5 mm/min.

A sintered body having a width of 25 mm, a thickness of 10 mm and a length of 110 mm was used as a test piece. The test piece was heated to a predetermined temperature, held at that temperature for 1 hour or more, then immersed in water and rapidly cooled, and the occurrence of cracks was confirmed by an ink check. The rapid cooling temperature difference (difference between the predetermined heating temperature and the water temperature) was gradually increased, and this operation was repeated until cracks occurred in the test piece. The temperature difference in rapid cooling at which the first crack was generated among the test pieces N was defined as the resistance to cold cracking of the test base.

The present invention will be described in more detail by the following examples, but the invention is not limited to these examples.

Manufacture of sanitary ware
Raw Materials The raw materials listed in Table 1 below are prepared, and these are mixed in the combinations listed in Table 2 so that the compositions listed in Table 3 are obtained. bottom.

In the table, the composition of the base material was measured by pulverizing the fired base material and using a fluorescent X-ray spectrometer (XRF) by the glass bead method. However, the amount of Li ₂ O in the base composition is a calculated value from the amount of Li ₂ O in the raw material (petalite) used and the compounding amount.

A glaze having the following composition was prepared, applied to the sanitary ware base, and fired at the maximum firing temperature shown in Table 2.

_SiO2 56.8 parts by weight _{Al2O3 8.3} parts by weight _{Fe2O3 0.1} parts by weight CaO 10.1 parts by weight MgO 1.1 parts by weight ZnO 5.1 parts by weight _K2O 1.9 parts by weight parts Na ₂ O 1.4 parts by weight ZrO ₂ 5.6 parts by weight Pigment 0.01 parts by weight

Various physical properties of the sanitary ware obtained by firing were as shown in Table 4 below.

In the table, the total amount of alkali metal oxides indicates the total amount of Li ₂ O, Na ₂ O and K ₂ O components in Table 3.

The minerals contained were identified by qualitative analysis using an X-ray diffractometer (XRD) using a measurement sample obtained by pulverizing the fired base material and press-molding the pulverized powder into a disk shape.

Quantification of Anorthite The amount of anorthite was obtained by performing Rietveld analysis on the X-ray diffraction pattern obtained by the powder analysis method and estimating the abundance of each crystal phase from the determined scale factor. Specifically, the procedure is as follows.

As a pretreatment, the obtained base material was pulverized to an average particle size of 10 μm or less to obtain a powder. In this example, a tungsten carbide (WC) mortar and pestle were used. There is no limitation on the grinding method, and a general grinding tool such as a ball mill or mortar may be used.

The average particle size was measured by the following procedure.
An aqueous dispersion of the base powder was prepared using a Malvern Panalytical ultrasonic disperser HYDRO LV. The dispersion conditions were as shown below.
・Dispersant: None ・Frequency: 40kHz
・Irradiation time: 15 seconds ・Pause time before measurement: 10 seconds ・Pump speed: 3500 rpm

Using the obtained aqueous dispersion, the average particle size was measured. For the measurement, a MASTERSIZER3000 laser diffraction particle measuring device manufactured by Malvern Panalytical and software MASTERSIZER ver3.72 were used, and the volume average value was determined by a laser diffraction/scattering method based on Mie theory. The refractive index of the dispersion medium was set to 1.33.

An X-ray diffraction pattern was then obtained using the powder. The X-ray diffraction pattern was obtained using X'Pert manufactured by Malvern Panalytical under the conditions of X-ray source CuKα ray (wavelength λ = 0.15406 nm), diffraction angle (2θ) 10 to 60°, and sampling width 0.02°. was done. Since it is said that the larger the X-ray diffraction peak of the obtained crystal phase, the higher the accuracy of quantification, the intensity of the highest peak among the X-ray diffraction peaks was measured to be 10,000 counts or more. The obtained X-ray diffraction peaks were analyzed using software High Score Plus (ver. 4.9).

The crystal phase contained in the base is determined by comparing the X-ray diffraction pattern obtained under the above conditions with the PDF (Powder Diffraction File) data of the ICDD (International Center for Diffraction Data) and selecting the matching crystal phase. identified.

For the identified crystalline phases, Rietveld analysis was performed by the external standard method. Al ₂ O ₃ with a purity of 99.99% or higher was used as an external standard sample. An X-ray diffraction pattern is obtained from this external standard sample under the same measurement conditions as the powder, and its abundance (% by weight) is compared with the area of the obtained X-ray diffraction according to the COD (Crystallography Open Database) file. calculated and used as a reference.

Subsequently, X-ray diffraction data was obtained for each substrate of Examples and Comparative Examples, and the diffraction pattern of only the identified crystal phase was quantitatively evaluated with reference to the COD file corresponding to each crystal phase. Since the total amount (% by weight) of each crystal phase obtained was less than 100%, the amount obtained by subtracting the total amount of each crystal phase from 100% was taken as the quantitative value (% by weight) of the glass phase (amorphous phase).

"HighScore Plus" software was used to process background, X-ray diffraction patterns required for quantification of diffraction peaks by Kα2 and Kβ, and smoothing.

In addition, the "water absorption", "closed porosity", "firing shrinkage", "softening deformation", and "bending strength" in the table were measured according to the above-described measurement methods, and furthermore, "bulk density", "glaze "matching with" and "thermal shock resistance" were measured as follows.

Bulk Density JIS R1634: 1988 Measured according to the method for measuring sintered body density and open porosity of fine ceramics.

Matching with Glaze First, a raw material for sanitary ware was molded to prepare a test piece of 20 mm×8 mm×150 mm. A glaze of 0.6 to 0.7 mm thick was applied to one surface of the test piece, and the test piece was fired with the 8 mm thick×150 mm long surface (side surface) facing downward. After firing, the warp at the center of the unglazed side was measured with reference to the length direction, and the amount of warp was defined as the amount of deformation.

A sintered body having a width of 25 mm, a thickness of 10 mm and a length of 110 mm was used as a test piece. The test piece was heated to a predetermined temperature, held at that temperature for 1 hour or more, then immersed in water and rapidly cooled, and the occurrence of cracks was confirmed by an ink check. The rapid cooling temperature difference (difference between the predetermined heating temperature and the water temperature) was gradually increased, and this operation was repeated until cracks occurred in the test piece. The thermal shock resistance of the test base was defined as the rapid cooling temperature difference at which cracks occurred at 50% of the N number of the test piece.

Claims (7)

A sanitary ware comprising a fusible ceramic base and a glaze layer, wherein a part of the base is exposed to the outside without the glaze layer,
The base material is
(A) anorthite;
(B) containing an alkaline component,
Here, the amount of the alkali component is 5 to 10% by weight in terms of oxide (A ₂ O) with respect to the base, and the closed porosity of the base is 12 to 15% by volume. Sanitary ware. 2. The sanitary ware according to claim 1, wherein the substrate further contains (C) at least one selected from the group consisting of corundum, chamotte, quartz, hollow silica, hollow alumina, zirconia, zircon, cordierite, and mullite. The sanitary ware according to claim 2, wherein the component (C) is corundum. The glaze layer contains 55 to 80 parts by weight of SiO ₂ , 5 to 13 parts by weight of Al ₂ O ₃ , 0.1 to 0.4 parts by weight of Fe ₂ O ₃ and 0.8 to 3.0 parts by weight of MgO. 8 to 17 parts by weight of CaO, 3 to 8 parts by weight of ZnO, 1 to 4 parts by weight of K ₂ O, and 0.5 to 2.5 parts by weight of Na ₂ O. Sanitary ware according to any one of the above. 5. The sanitary ware according to claim 4, wherein said glaze layer further contains 0 to 15 parts by weight of ZrO ₂ and 0 to 20 parts by weight of pigment. The sanitary ware according to any one of claims 1 to 5, wherein the base material has a water absorption rate of less than 2%. The sanitary ware according to any one of claims 1 to 6, wherein the base material contains 3 to 10% by weight of calcium in terms of oxide (CaO).