阅读说明：本技术 卫生陶器 (Sanitary earthenware ) 是由 古贺直树 北崎聪 龟重裕由 冈安祐树 阿野知史 于 2021-03-01 设计创作，主要内容包括：本发明提供一种可兼具低吸水性和轻量性的卫生陶器。该卫生陶器具备玻化瓷质的陶器坯体和釉层,所述坯体的一部分不具备釉层并露出于外部,其中,所述坯体含有(A)钙长石和(B)碱金属成分,相对于所述坯体,碱金属成分的量以氧化物(A2O)换算为5～10重量％。(The invention provides sanitary ware having both low water absorption and lightweight. The sanitary ware comprises a vitreous porcelain body and a glaze layer, wherein a part of the body is exposed to the outside without the glaze layer, wherein the body contains (A) anorthite and (B) an alkali metal component, and the amount of the alkali metal component is 5 to 10 wt% in terms of oxide (A2O) with respect to the body.)

1. A sanitary ware comprising a vitreous porcelain body and a glaze layer, wherein a part of the body is exposed to the outside without the glaze layer,

the green body contains:

(A) anorthite; and

(B) an alkali metal component, and a metal oxide,

wherein the alkali metal component is present in an amount of oxide (A) relative to the weight of the body₂O) is 5 to 10 wt%.

2. Sanitary ware according to claim 1, wherein,

the green body also contains (C) at least 1 of corundum, fire clay, quartz, hollow silica, hollow alumina, zirconia, zircon, cordierite and mullite.

3. Sanitary ware according to claim 2, wherein,

the component (C) is corundum.

4. Sanitary ware according to any one of claims 1 to 3, wherein,

the glaze layer contains SiO₂: 55-80 parts by weight of Al₂O₃: 5 to 13 parts by weight of Fe₂O₃: 0.1-0.4 parts by weight, MgO: 0.8-3.0 parts by weight of CaO: 8-17 parts by weight of ZnO: 3 to 8 parts by weight of K₂O: 1 to 4 parts by weight, and Na₂O: 0.5 to 2.5 parts by weight.

5. Sanitary ware according to claim 4, wherein,

the glaze layer also contains ZrO₂: 0-15 parts by weight of pigment: 0 to 20 parts by weight.

6. Sanitary ware according to any one of claims 1 to 5, wherein,

the closed porosity of the green body is 15% by volume or more.

7. Sanitary ware according to any one of claims 1 to 6, wherein,

the water absorption of the green body is less than 2%.

8. Sanitary ware according to any one of claims 1 to 7, wherein,

the green body contains 3 to 10 wt% of calcium in terms of oxide (CaO).

Technical Field

The present invention relates to sanitary wares used in toilets, wash basins and the like.

Background

Since sanitary wares are much heavier than tableware and the like, when porcelain having a large amount of glass is used, they are seriously deformed by their own weight during firing, and thus are difficult to manufacture. On the other hand, if ceramics with a small amount of glass and a large amount of crystal are used, water absorption occurs in the unglazed portion. Therefore, there is a possibility that the waste water is absorbed and damaged by freezing. Therefore, as sanitary ware, a vitreous porcelain body is used which is interposed between porcelain and pottery and suppresses deformation during firing and minimizes water absorption.

That is, sanitary ware generally includes a vitreous ceramic body and a glaze layer, and a structure in which the glaze layer is formed on most of the vitreous ceramic and a part of the vitreous ceramic is exposed. For example, in the case of sanitary ware as a toilet, such a structure hardly deforms under a seating load, and the surface is hardly damaged while maintaining sufficient strength, thereby maintaining the sanitary property. In addition, since the vitreous ceramic body is dense and the water absorption is eliminated as much as possible, the problem due to the water absorption of the exposed portion is also prevented.

Since sanitary wares are large and have a complicated shape even in ceramic ware products, they have a thick wall structure in order to maintain the strength of the products. In the existing blank, the bending strength is 50-80 MPa, and the wall thickness of the product needs to be about 7-12 mm in terms of the strength. Therefore, the weight of the product is increased, and there is still a demand for lighter sanitary ware in terms of transportation, construction, and size increase.

Conventionally, a technique has been proposed in which the bending strength is maintained at the above strength, and the water absorption property is reduced and the weight of the product is reduced.

For example, japanese patent laid-open No. 2000-319061 (patent document 1) discloses: a ceramic ware comprising a body and a glaze layer formed thereon at a necessary portion, wherein the body is made of a ceramic body having water absorption at a central portion thereof, and the body is fired after impregnating a molded body with an alkali metal component at least at a portion of a surface of the body where the glaze layer is not formed so that the water absorption at the portion is smaller than that at the central portion of the body

Japanese patent laid-open No. 2002-68821 (patent document 2) discloses a sanitary ware comprising a ceramic ware body and a glaze layer formed on a necessary portion of the ceramic ware body, wherein the main component constituting the ceramic ware body is SiO₂：50～75wt％、Al₂O₃：20～45wt％、Na₂O: 0.5 wt% or more, and further, Na₂O, selected from Li₂O、K₂The total of at least 1 component of O and at least 1 component selected from CaO, MgO, BaO and BeO is 2-6 wt%, and further, the green body contains at least 1 or more selected from quartz, cristobalite, mullite and corundum as crystals, and the total crystal amount is 10-60 wt% relative to 100 of the entire green body.

Japanese patent laid-open No. 2001-348263 (patent document 3) discloses a sanitary ware composed of a ceramic ware body and a glaze layer formed on a necessary portion of the body, wherein the body comprises: a crystal phase containing mullite and quartz as main components; with SiO₂、Al₂O₃A glass phase as a main component; and a crystal phase comprising a mineral selected from the group consisting of cristobalite, andalusite, sillimanite, kaolinite and corundum as required, wherein the base material of the body is SiO₂：50～65wt％、Al₂O₃: 30-45 wt%, alkali metal oxide: 0.1 to 2 wt% and a divalent metal oxide: 0.1 to 10 wt% of a CaO component as the divalent metal oxide component, and a CaO component segregation portion in which the CaO component is segregated is dispersed in the green body.

Japanese patent laid-open publication 2002-68825 (patent document 4) discloses a ceramic ware, which is characterized in that a green body for sanitary ware is manufactured by a method comprising the steps of: a molding step of molding a skeleton-forming material represented by pottery stone, silica stone, agalmatolite, fireclay, alumina shale, and kaolin, a moldable material represented by pottery clay, kaolin, and siliconMolding the limestone, calcium raw materials represented by anorthite and kiln raw materials composed of sintering aid raw materials represented by feldspar and dolomite as the case requires to obtain a molded blank; a glazing step of glazing a necessary portion as required; and a firing step in which the molded body obtained in the molding step has a filling rate of 68 vol% or more and the composition of the main component of the body is SiO₂: 45-70 wt% of Al₂O₃: 25 to 50 wt% of Na₂O、K₂O、Li₂At least 1 alkali metal oxide of O and/or at least 1 alkaline earth metal oxide selected from CaO, MgO, BaO and BeO as other component, and Na₂O、K₂O、Li₂The total amount of at least 1 alkali metal oxide of O is 2 wt% or less, and is selected from Na₂O、K₂O、Li₂The total amount of at least 1 alkali metal oxide of O and at least 1 alkaline earth metal oxide selected from CaO, MgO, BaO and BeO is 10 wt% or less, and at least CaO component is contained as an alkaline earth metal oxide component.

WO97/26223 (patent document 5) discloses a ceramic body which is composed of a crystal phase and a glass phase and contains an alkali metal oxide and an alkaline earth metal oxide in the glass phase, wherein the molar ratio of the alkaline earth metal oxide to the total amount of the alkali metal oxide and the alkaline earth metal oxide is 30 mol% or more.

This technique reduces the amount of firing deformation, but cannot achieve both low water absorption and light weight.

Japanese patent laid-open No. 2001-287981 (patent document 6) discloses a sanitary ware comprising a ceramic ware body and a glaze layer formed on a necessary portion of the body, wherein the composition of a main component constituting the body is SiO₂: 45-70 wt% of Al₂O₃: 25 to 50 wt%, and further comprising 6 wt% or less of an alkali metal oxide and at least 1 alkaline earth metal oxide selected from CaO, MgO, BaO and BeO in total, wherein the amount of the alkali metal oxide in the green body is 2 wt% or moreNa2O as an essential component and K as an optional component in the alkali metal oxide₂O, and, relative to Na₂O and K₂Total amount of O, Na₂O is 20% by weight or more.

Japanese patent laid-open No. 2002-255630 (patent document 7) discloses a sanitary ware comprising a ceramic ware body and a glaze layer formed on a necessary portion of the body, wherein the composition of a main component constituting the body is SiO₂: 45-70 wt% of Al₂O₃: 25 to 50 wt%, and 10 wt% or less in total of an alkali metal oxide and an alkaline earth metal oxide, wherein the amount of the alkali metal oxide in the green body is 2 wt% or less, CaO and MgO are contained as essential components in the alkaline earth metal oxide, and MgO is 20 wt% or more based on the total amount of CaO and MgO.

Japanese patent laid-open publication No. 2002-80266 (patent document 8) discloses a sanitary ware composed of a ceramic ware body and a glaze layer formed on an essential portion of the body, wherein the body comprises: a crystal phase containing mullite and quartz as main components; with SiO₂、Al₂O₃A glass phase as a main component; and a crystal phase comprising a mineral selected from the group consisting of cristobalite, andalusite, sillimanite, kaolinite and corundum as required, wherein the base material of the body is SiO₂：50～65wt％、Al₂O₃: 30-45 wt%, alkali metal oxide: 0.1 to 2 wt%, divalent metal oxide: 0.1 to 10 wt% of a divalent metal oxide component containing at least CaO, wherein CaO component segregation parts, in which the CaO component segregates, are dispersed in the green body, and fibrous wollastonite having an aspect ratio of 10 or more is used as the raw material for the green body.

Japanese patent laid-open publication 2011-162376 (patent document 9) discloses a lightweight pottery, which is characterized in that: comprising a crystal phase containing at least mullite, quartz and anorthite as main components and SiO₂、Al₂O₃The glass phase as the main component constitutes the fired body blankA plurality of independent air holes surrounding the anorthite are formed in the fired body blank, and the bulk density is 2.0-2.4 g/cm³。

Further, Japanese patent laid-open Nos. 2002-97068 (patent document 10), 2002-114565 (patent document 11), and 2002-114566 (patent document 12) disclose sanitary wares having a reduced weight while maintaining a bending strength.

On the other hand, as a glaze for sanitary ceramics, for example, a glaze described in WO99/61392 (patent document 13) is used.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2000-319061;

patent document 2: japanese patent laid-open No. 2002-68821;

patent document 3: japanese patent laid-open No. 2001-348263;

patent document 4: japanese patent laid-open No. 2002-68825;

patent document 5: WO 97/26223;

patent document 6: japanese patent laid-open No. 2001-287981;

patent document 7: japanese patent laid-open No. 2002-255630;

patent document 8: japanese patent laid-open No. 2002-80266;

patent document 9: japanese patent laid-open No. 2011-;

patent document 10: japanese patent laid-open No. 2002-97068;

patent document 11: japanese patent laid-open No. 2002-114565;

patent document 12: japanese patent laid-open No. 2002-114566;

patent document 13: WO 99/61392;

patent document 14: japanese patent laid-open No. Hei 4-2679.

Disclosure of Invention

Problems to be solved by the invention

There is still a demand for a technique for reducing the weight of products while maintaining the strength while ensuring low water absorption for sanitary wares.

The invention aims to provide sanitary ware which can have both low water absorption and light weight.

Means for solving the problems

In this regard, the present inventors found that: in terms of vitreous china, it has been difficult to realize sanitary ware having both low water absorption and lightweight properties by using a composition which is known to be suitable as a component of sanitary ware in the prior knowledge. The present invention has been completed based on the above findings.

In addition, the sanitary ware according to the present invention,

the ceramic body comprises a vitreous porcelain body and a glaze layer, wherein a part of the body is exposed to the outside without the glaze layer, and the ceramic body comprises:

(A) anorthite; and

(B) an alkali metal component, and a metal oxide,

wherein the amount of the alkali metal component is oxide (A) relative to the green body₂O) is 5 to 10 wt%.

Detailed Description

Sanitary ware and green body

In the present specification, "sanitary ware" refers to toilets, washbasins, and ceramic products used around the toilets or washbasins, and specifically refers to toilets, urinals, water tanks, floor drains (サナ), washbasins, hand washers, and the like. The sanitary ware of the present invention is preferably: the material is described in JIS a 5207: 2019 "type of 7.1 material" and satisfies many properties described in "quality of 7.2 pottery".

The body of the sanitary ware of the present invention is basically a vitreous porcelain body. In the present specification, the term "vitreous ceramic greenware" has a general meaning as understood in the technical field related to sanitary ware, and therefore, the term "vitreous ceramic greenware" as a greenware of the sanitary ware of the present invention is understood to have a general meaning except for having the features of the present invention described later.

The "vitreous porcelain body" in sanitary ware of the present invention contains (A) anorthite and (B) an alkali metal component, and is formed by mixing the above componentsThe amount of the alkali metal component is oxide (A)₂O) is preferably 5 to 10% by weight, more preferably 6 to 10% by weight. Among them, the alkali metal components are preferably Li, Na and K, for example, and therefore the oxide thereof means Li₂O、Na₂O、K₂O。

According to conventional knowledge, in large-sized ceramic products such as sanitary ware, the alkali metal component content is not preferable in terms of strength of the product, deformation during firing, and the like in the above range, and is generally considered to be an inappropriate amount. However, in the case of a green body in which such a large amount of alkali metal component coexists with anorthite (a), the product can be reduced in weight because of low water absorption and high strength.

According to a preferred form of the invention, the body of the sanitary ware of the invention can also be characterized by its closed pores. In the present specification, "closed pores" mean pores that are present inside the green body and do not communicate with the outside air, and in a preferred embodiment of the present invention, the closed pore ratio obtained by a measurement method of the "closed pore ratio" described later is 15% by volume or more.

According to a preferred form of the invention, the body of sanitary ware according to the invention can also be characterized by its water absorption. In the present specification, the water absorption obtained by the measurement method of "water absorption" described later is less than 2%.

The reason why sanitary ware having low water absorption and reduced weight is realized in the present invention is not clear, but the following theory is considered. This theory is ultimately the hypothesis, and the invention is not limited by this theory.

As one theory, it is believed that in the green body, pores generated when anorthite is generated at 900 to 1000 ℃ are maintained until the maximum firing temperature is reached, and thereafter, the open pores may be closed.

If the vitreous body containing kaolin is heated, metakaolin is first generated through a dehydration reaction of kaolin. If limestone is mixed in advance as a blank raw material, metakaolin reacts with the limestone at 900-1000 ℃ to generate anorthite (CaAl)₂Si₂O₈)。

Al₂O₃·2SiO₂+CaCO₃→CaAl₂Si₂O₈+CO₂···(1)

At this time, the consumed portion of the limestone becomes pores, and anorthite is generated around the pores.

Under the condition of common sanitary ware body, metakaolin is decomposed at above 1000 ℃ to generate mullite and SiO₂And (3) glass. Accordingly, it is possible to increase the flux component at the highest temperature while decreasing the closed cell amount.

3(Al₂O₃·2SiO₂)→3Al₂O₃·2SiO₂+4SiO₂···(2)

However, it is considered that in the anorthite formation reaction (reaction formula (1)) which occurs at a relatively low temperature during the temperature rise, kaolinite is consumed, so that reaction formula (2) does not occur, and mullite and SiO are not formed₂Glass, and pores generated in the anorthite-forming reaction are likely to remain directly.

In this way, the amount of pores reaches the maximum at the maximum firing temperature of 1100 to 1200 ℃ at which the melting reaction occurs, and the alkali metal component is formed at a high concentration during the melting reaction, so that the viscosity of the glass is reduced by a relatively small amount in which the increase in temperature rise is suppressed, and the fluidity is improved, and the open pores can be reliably closed. As a result, it is considered that a large number of closed cells can be left while the open cells are closed, and excellent low water absorption and lightweight properties can be achieved.

As a raw material contributing to the production of anorthite, a calcium (Ca) -containing raw material such as wollastonite may be used instead of limestone. In the present invention, the calcium-containing material is at least 1 selected from limestone, wollastonite, dolomite, and apatite, and preferably either one or both of limestone and wollastonite. The calcium-containing raw materials are mixed with metakaolin (Al) at 900-1000 DEG C₂O₃·2SiO₂) Reacting to generate anorthite.

When wollastonite is used as a calcium-containing raw material, anorthite is considered to be produced by a reaction of the following formula (reaction formula (3)).

Al₂O₃·2SiO₂+CaSiO₃→CaAl₂Si₂O₈+SiO₂···(3)

In the reaction of the reaction formula (3) for producing anorthite, CO is not produced₂Gas, therefore, does not cause an increase in pores, and the density change during firing is small. In addition, in the reaction of the reaction formula (3), SiO is generated in excess₂Glass, thus the remaining SiO₂The glass together with the glass produced in the subsequent melting reaction helps to close the open pores. That is, when wollastonite is used as a calcium-containing raw material, the amount of closed pores in the green body after firing is reduced as compared with the case of using limestone, and it is advantageous in that deformation caused by firing can be reduced.

According to a preferred embodiment of the present invention, the amount of anorthite in the green body is preferably 10 to 45% by weight, and more preferably 13 to 31% by weight. The amount of anorthite can be determined by Rietveld analysis of an X-ray diffraction pattern obtained by powder analysis and estimation of the amount of each crystal phase from the determined scale factor. The detailed method for determining anorthite is described in the examples below.

According to a preferred embodiment of the present invention, the amount of the alkali metal component in terms of oxide is 5 to 10 wt%, more preferably 6 to 9 wt%, based on the green body. The closed cell ratio is more preferably 20% by volume at the lower limit, and more preferably 31% by volume at the upper limit, and the water absorption ratio is preferably less than 1%.

In a preferred embodiment of the present invention, the sanitary ware body contains 3 to 10 wt%, preferably 3 to 9 wt%, and more preferably 4 to 9 wt% of calcium in terms of oxide (CaO).

(C) The components: aggregate material

The sanitary ware body of the present invention may contain an aggregate component from the viewpoint of strength. As aggregate components, the following can be generally used: a component which does not react during firing and suppresses shrinkage or softening deformation during firing, or a component which affects the strength of a fired body, is added to a vitreous ceramic body.

According to a preferred embodiment of the present invention, at least 1 selected from the group consisting of corundum, chamotte, quartz, hollow silica, hollow alumina, zirconia, zircon, cordierite and mullite is preferably contained as the aggregate component, i.e., (C).

In the case of the present invention, by using these aggregate components, the following advantages are expected to be obtained. That is, as described above, when metakaolin is consumed by the anorthite production reaction (reaction formula (1)) and a relatively large amount of anorthite is produced, a large shrinkage may occur in the reaction temperature range. If this shrinkage occurs, the fit with the glaze is damaged. Among them, the aggregate is a material which is not related to the reaction formula (1) and hardly increases the flux component in the melting reaction. Therefore, the use of these aggregates is advantageous from the viewpoint of low water absorption and light weight. Further, according to a preferred embodiment of the present invention, sanitary ware having excellent thermal shock resistance can be obtained by using these aggregate components.

In the present invention, the shape and composition of the aggregate component can be identified from the reflection electron image of a Scanning Electron Microscope (SEM) of the ground surface of sanitary ware and the element map of energy dispersive X-ray analysis (EDX).

Raw materials and composition of sanitary pottery body

The raw materials for forming the sanitary ware body can be prepared from conventionally known raw materials by considering the composition thereof. Specifically, silica sand, feldspar, limestone, wollastonite, clay, alumina, fireclay, and the like can be used. The composition of the green body of sanitary ware of the present invention is preferably as follows, and the raw materials for the green body of sanitary ware are mixed to form the following composition.

SiO₂40 to 65 parts by weight of

Al₂O₃20 to 50 parts by weight of

3-10 parts by weight of CaO

0.1 to 1 part by weight of MgO

K₂O3-6 parts by weight

Na₂0.5 to 5 parts by weight of O

Li₂0 to 2 parts by weight of O

Glaze layer

Although the glaze layer of the sanitary ware of the present invention is not limited, according to a preferred embodiment of the present invention, the composition of the glaze layer preferably has a composition as shown below in terms of oxide.

SiO₂55 to 80 parts by weight of

Al₂O₃5 to 13 parts by weight of a stabilizer

Fe₂O₃0.1 to 0.4 part by weight

8-17 parts by weight of CaO

0.8 to 3.0 parts by weight of MgO

3-8 parts of ZnO

K₂1 to 4 parts by weight of O

Na₂0.5 to 2.5 parts by weight of O

ZrO₂0 to 15 parts by weight

0 to 20 parts by weight of a pigment

The raw material for the glaze layer can be prepared from conventionally known raw materials, taking into account the composition thereof. For example, there may be mentioned: silica sand, feldspar, limestone, dolomite, alumina, zinc white, zircon and the like.

According to a preferred embodiment of the present invention, the sanitary ware body and the glaze layer are preferably combined so that the body and the glaze layer do not have a large difference in deformation amount after firing and do not adversely affect the shape or surface condition of the sanitary ware.

For example, the preferable combination is that the amount of deformation of the glaze in the embodiment described later is 5mm or less. Further, according to another aspect of the present invention, it is preferable that the linear expansion coefficient of the green body is higher than the linear expansion coefficient of the glaze by 5 × 10^-7/K～10×10^-7A combination of about/K.

Production of sanitary ware

The sanitary ware of the present invention can be obtained by casting a slurry prepared from the above-mentioned raw material for a green body using a mold such as gypsum to obtain a molded body, drying the molded body, glazing the dried body, and firing the glazed body. In the case of the present invention, as described above, it is preferable to determine the firing conditions so as to reliably cause these reactions and phenomena, because the pores generated when anorthite is produced are maintained until the maximum firing temperature is reached, and then the pores are closed, thereby achieving good low water absorption, strength, and weight reduction. According to one embodiment of the present invention, firing is preferably performed by raising the temperature to about 200 ℃ per hour and holding the temperature at a maximum temperature of 1180 ℃ to 1200 ℃ for 2 hours.

The "closed cell ratio" and "water absorption ratio" defined in the present invention were measured as follows.

Water absorption rate

As a measurement sample, a fired body having a size of 7 mm. times.8 mm. times.70 mm was prepared by molding or cutting. The sample was dried at 110 ℃ for 24 hours, and the weight of the sample was determined as the dry weight. Thereafter, the sample was placed in a container and degassed for 20 minutes using a vacuum pump. Distilled water was poured into the container containing the sample while maintaining the vacuum, and the container was degassed for 60 minutes. The atmosphere was opened, the sample was immersed in water, the water on the surface of the fished sample was wiped off with a cloth or the like, and the weight was measured. This was taken as the weight upon water absorption. The water absorption was calculated by the following equation.

(math figure 1)

Closed porosity

From the values obtained to obtain the water absorption, the apparent density was obtained by the following formula.

(math figure 2)

"true density" was further determined as described below. That is, the green fired body was pulverized to such an extent that it did not contain closed pores, and the density of the powder was measured using a pycnometer using water as a solvent. This was taken as the "true density" of the body.

From the apparent density and the true density obtained above, the closed cell ratio is defined by the following equation.

(math figure 3)

(examples)

The present invention will be described in further detail with reference to the following examples, but the present invention is not limited to these examples.

Production of sanitary ware

Raw materials

The raw materials shown in table 1 below were prepared, mixed in the composition shown in table 3 according to the combination shown in table 2, and pulverized by a ball mill or the like as needed to form a sanitary ware body raw material.

In the table, the composition of the green body was measured by a glass bead method using a fluorescent X-ray analyzer (XRF) after crushing the fired green body. Among them, Li in composition of green body₂O amount derived from Li in raw material (petalite) used₂The calculated values of the O amount and the mixed amount are shown.

The sanitary ware body was glazed with the following composition, and fired at the firing temperature shown in table 2 as the maximum temperature.

SiO₂56.8 parts by weight

Al₂O₃8.3 parts by weight

Fe₂O₃0.1 part by weight

CaO 10.1 parts by weight

MgO 1.1 part by weight

ZnO 5.1 weight parts

K₂O1.9 parts by weight

Na₂O1.4 parts by weight

ZrO₂5.6 parts by weight

0.01 part by weight of pigment

The properties of the sanitary ware obtained by firing are shown in table 4 below.

In the table, the total amount of alkali metal oxides represents Li in the composition of the green body in Table 3₂O、Na₂O、K₂The total amount of the O component.

Further, the contained minerals were identified by pulverizing the fired green body, pressing the pulverized powder into a disk shape, and subjecting the obtained product as a measurement sample to qualitative analysis using an X-ray diffraction apparatus (XRD).

Caliper quantification

The amount of anorthite was determined by Rietveld analysis of an X-ray diffraction pattern obtained by powder analysis and estimation of the amount of each crystal phase from the determined scale factor. Specifically, the amount of anorthite was determined by the following procedure.

As a pretreatment, the obtained green body is pulverized to an average particle diameter of 10 μm or less to obtain a powder. In this example, a mortar and pestle made of tungsten carbide (WC) were used. The method of pulverization is not limited, and a common ball mill, mortar, or the like can be used as the pulverization tool.

The average particle size was measured by the following procedure.

An aqueous dispersion of green powder was prepared using an ultrasonic dispersion apparatus HYDRO LV manufactured by Malvern Panalytical. The dispersion conditions were set as follows.

Dispersant: none;

frequency: 40 kHz;

irradiation time: 15 seconds;

measurement of pause time before start: 10 seconds;

the pump speed: 3500 rpm.

Using the resulting aqueous dispersion, the foregoing average particle diameter was measured. For the measurement, a volume average value was obtained by a laser diffraction/scattering method based on Mie theory using a MASTERSIZER3000 laser diffraction type particle measuring apparatus manufactured by Malvern Panalytical and software MASTERSIZER 3.72. The refractive index of the dispersion medium was 1.33.

Then, an X-ray diffraction pattern was obtained using the powder. The X-ray diffraction pattern was obtained using X' PERT manufactured by Malvern Panalytical under the conditions of an X-ray source CuK α ray (wavelength λ 0.15406nm), diffraction angle (2 θ)10 ° to 60 °, and sampling range 0.02 °. The larger the X-ray diffraction peak of the obtained crystal phase, the higher the accuracy of the quantification, and therefore, the measurement was performed so that the intensity of the highest peak among the X-ray diffraction peaks was 1 ten thousand counts or more. The resulting X-ray diffraction peaks were analyzed using software High Score Plus (version 4.9).

The crystalline phase contained in the green body was identified in the following manner: the X-ray Diffraction pattern obtained under the above conditions was compared with the Data of a Powder Diffraction File (PDF: Powder Diffraction File) of the International Centre for Diffraction Data (ICDD: International Centre for Diffraction Data), and the corresponding crystal phase was selected for identification.

Regarding the identified crystalline phase, Rietveld analysis was performed by the external standard method. Al with a purity of 99.99% or more is used₂O₃Used as external standard sampleThe method is as follows. An X-ray diffraction pattern was obtained from the external standard sample under the same measurement conditions as those of the powder, and the amount (wt%) of the X-ray diffraction pattern was calculated by comparing the X-ray diffraction area obtained with a Crystallography Open Database (COD) file.

Next, X-ray diffraction data of each of the green bodies of examples and comparative examples were obtained, and quantitative evaluation was performed with reference to COD files corresponding to each crystal only for the diffraction patterns of the identified crystal phases. 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 a quantitative value (% by weight) of the glass phase (amorphous phase).

The background processing, the processing of the X-ray diffraction pattern required for quantification by the diffraction peak of K α 2 or K β, smoothing processing, and the like are performed by the "HighScore Plus" software.

The "water absorption" and "closed cell content" in the table were measured by the above-mentioned measurement methods, and the "bulk density", "firing shrinkage", "softening deformation", "flexural strength" and "thermal shock resistance" were measured as follows.

Bulk density

According to JIS R1634: 1988 method for measuring density and open pore ratio of sintered body of fine ceramics.

Firing shrinkage

The green body before firing was cut into 7 mm. times.8 mm. times.70 mm to prepare a molded body sample. The length of the central portion of the molded sample was measured. Next, the sample was fired, and the length of the central portion of the fired sample was measured. The shrinkage was calculated from the difference in shrinkage.

Amount of softening deformation

A test piece of a molded body having a width of 30mm, a thickness of 10mm and a length of 250mm was baked while being held at a span of 200mm, and the amount of sagging of the center portion of the baked test piece was measured as a measurement value of softening deformation. Since the magnitude of the softening deformation is inversely proportional to the square of the thickness, the value obtained by converting the thickness into 10mm is taken as the value of the softening deformation amount.

(math figure 4)

Bending strength

According to JIS A1509-4: 2014 to perform the measurement. Specifically, the following is described. As a rectangular parallelepiped sample, a fired body molded or cut into 7 mm. times.8 mm. times.70 mm was prepared. The 3-point flexural strength of the sample was measured. The measurement conditions were set as follows: span 50mm, crosshead speed 0.5 mm/min.

As a round bar sample, a fired body having a diameter of 14mm X150 mm was prepared. The 3-point flexural strength of the sample was measured. The measurement conditions were set as follows: span 100mm, crosshead speed 2.5 mm/min.

In combination with glaze

First, a sanitary ware body material was molded to prepare a test piece of 20 mm. times.8 mm. times.150 mm. The test piece was baked by applying glaze with a thickness of 0.6 to 0.7mm on one surface and facing the surface (side surface) with a thickness of 8mm × 150mm downward. After firing, the warp of the central portion on the non-glazed surface side was measured with respect to the longitudinal direction, and the warp amount was used as the deformation amount.

Thermal shock resistance

The fired body having a width of 25mm, a thickness of 10mm and a length of 110mm was used as a test piece. The test piece was heated to a predetermined temperature, held at the temperature for 1 hour or more, and then put into water to be quenched, and the occurrence of cracks was confirmed by ink inspection. This operation was repeated until cracks were generated in the test piece by gradually increasing the temperature difference between the rapid cooling (the difference between the predetermined temperature for heating and the water temperature). The difference in the temperature at which 50% of the N number of the test piece was rapidly cracked was used as the thermal shock resistance of the test blank.