Sanitary pottery

Abstract

To provide a sanitary ware including a glaze layer that has a practical antivirus property.SOLUTION: A sanitary ware comprises a pottery substrate and a glaze layer formed on the surface of the pottery substrate. The glaze layer contains, as an antiviral agent, lanthanum of 5 wt.% or more in terms of lanthanum oxide (La2O3) or lanthanum of 9 mass% or more in terms of atomic weight measured by fluorescent X-ray analysis (XRF). Such a sanitary ware has a practical antivirus property.SELECTED DRAWING: Figure 3B

Description

Technical Field

[0001] The present invention relates to sanitary ceramics, and more particularly to sanitary ceramics having good antiviral properties.

Background Art

[0002] In sanitary ceramics, a glaze layer is formed on its outermost surface in order to ensure a hygienic surface and also to ensure the appearance design. In order to improve the sanitary surface, a technique of adding an antibacterial agent to the glaze layer has been proposed. For example, Patent Document 1 (CN111393188A) discloses a sanitary ceramic including a base glaze layer and a top glaze layer containing a nano silver antibacterial agent.

[0003] In addition, an example of imparting antiviral properties to a composite oxide has been reported. Patent Document 2 (WO2020 / 017493A1) suggests that a composite oxide ceramic containing a rare earth element and other specific metal elements has both water repellency and antibacterial and antiviral properties. Specifically, it is disclosed that a calcined powder (500°C) of a composite oxide ceramic (LMO) containing lanthanum (La) and molybdenum (Mo) exhibits higher activity against bacteriophage Qβ and Φ6 than a single oxide (La2O3 particles) (paragraphs 0067, 0069-0071, FIG. 8).

[0004] In Patent Document 2, although a comparison with a single oxide has not been confirmed, it is disclosed that calcined powders (500°C, 400°C, or 550°C) of composite oxide ceramics (LMO, LWO, LCMO (a part of La in LMO is replaced by cerium (Ce)), LMWO (a part of Mo in LMO is replaced by W)) containing lanthanum (La) and molybdenum (Mo) and / or tungsten (W) exhibit activity against bacteriophage Qβ and Φ6 (FIGS. 11, 14-17, 20).

[0005] In addition, in the cosmetics research report Vol.28, 2020, p43-52 (Non-Patent Document 1) written by the inventor of Patent Document 2, the same content as in Patent Document 2 is also disclosed. For bacteriophages Qβ and Φ6, CeO2 shows almost no activity, while La2O3 shows certain activity. On the other hand, it is disclosed that the anti-Qβ and Φ6 activities of La2O3 are lower than those of LMO (page 47, right column, second paragraph, Figure 7).

[0006] On the other hand, examples of imparting antiviral properties to liquid compositions have been reported. In Japanese Patent Application Laid-Open No. 2020-111546 (Patent Document 3), an antiviral composition containing a rare earth salt, a zinc salt, and water is proposed. Specifically, an aqueous solution containing lanthanum chloride, cerium chloride, neodymium chloride, or ytterbium acetate and zinc gluconate has a lower virus infection titer (Log(PFU)), that is, higher antiviral properties, compared to an aqueous solution lacking either the rare earth salt or the zinc salt. Patent Document 3 discloses processing the antiviral composition into fibers and also suggests processing it into coating agents such as paints, but it does not describe processing it into ceramic materials or even glaze materials.

[0007] So far, no examples have been reported that rare earth elements, especially lanthanum alone, have antiviral properties that can withstand practical use. On the other hand, due to the recent COVID-19 pandemic and other factors, the need for sanitary ceramics with practical antiviral properties has been increasing. Furthermore, generally, when additives are added to glazes, the surface of sanitary ceramics becomes rough, which may not be desirable from the perspectives of antifouling properties or design.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Literature

[0009]

Non-Patent Literature 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] The inventors of the present invention have experimentally confirmed that by including a specific amount or more of lanthanum in the glaze layer of sanitary ceramics, lanthanum alone exhibits practical antiviral properties. The present invention is based on such findings.

[0011] Therefore, an object of the present invention is to provide sanitary ceramics having a glaze layer with practical antiviral properties.

Means for Solving the Problems

[0012] And the sanitary ceramics according to the present invention are sanitary ceramics comprising a ceramic body and a glaze layer formed on the surface of the ceramic body, wherein the glaze layer contains lanthanum as an antiviral agent in an amount of 5% by weight or more in terms of lanthanum oxide (La2O3). Also, the sanitary ceramics according to the present invention are sanitary ceramics comprising a ceramic body and a glaze layer formed on the surface of the ceramic body, wherein the glaze layer contains lanthanum as an antiviral agent in an atomic abundance measured by X-ray fluorescence analysis (XRF) of 9% by mass or more.

Effects of the Invention

[0013] According to the present invention, there is provided sanitary ceramics having a glaze layer with practical antiviral properties.

Brief Description of the Drawings

[0014]

Fig. 1A

Fig. 1B

Fig. 2

Fig. 3A

Fig. 3B

Fig. 4A

Fig. 4B

Fig. 5A

Fig. 5B

Fig. 6A

Fig. 6B

Fig. 6C

MODE FOR CARRYING OUT THE INVENTION

[0015] Definition In the present invention, "sanitary pottery" means pottery products used around toilets and washrooms, specifically including toilets, urinals, toilet bowls, toilet tanks, washbasins in washstands, washbasins, etc. Further, "pottery" means among ceramics, those with a slightly absorbent texture due to the firing of the body and with a glaze applied to the surface.

[0016] Regarding the present invention, the statement that lanthanum in a specific amount or more "alone" exhibits practical antiviral properties means that, while the composite oxides disclosed in Patent Document 2 exhibit antiviral properties because they are composed of lanthanum and other metal elements (Mo, W), and while the liquid composition disclosed in Patent Document 3 exhibits antiviral properties because it contains rare earth salts and other metal salts (zinc salts), it means that lanthanum in a specific amount or more itself exhibits practical antiviral properties.

[0017] Sanitary ware The sanitary pottery according to the present invention, as shown in Fig. 1A, comprises at least a pottery body 10 and a glaze layer 20 formed on the surface thereof and containing lanthanum in a specific amount or more.

[0018] The sanitary pottery 1 according to the present invention may further comprise one or two or more other glaze layers between the pottery body 10 and the glaze layer 20 containing lanthanum in a specific amount or more. For example, according to one aspect of the present invention, as shown in Fig. 1B, the sanitary pottery 1 comprises a pottery body 10, a glaze layer 30 formed on the surface of the pottery body 10, and a glaze layer 20 containing lanthanum in a specific amount or more formed on the surface of the glaze layer 30. In the present invention, the glaze layer 30 may also be referred to as a base glaze layer, and the glaze layer 20 as an antiviral glaze layer. The base glaze layer 30 is not particularly limited and may be a glaze layer normally applied to the pottery body.

[0019] Ceramic body The pottery body 10 is not particularly limited and may be a conventionally known pottery body. That is, it may be appropriately formed from a sanitary pottery body slurry prepared using silica sand, feldspar, clay, etc. as raw materials.

[0020] Glaze layer In the present invention, the glaze layer 20 contains, as its components, lanthanum in a specific amount or more as an antiviral agent and a glaze material capable of realizing the surface properties described later together with the antiviral agent.

[0021] Antiviral agent In the present invention, the antiviral agent is lanthanum (La).

[0022] Content In one aspect of the present invention, when the total of lanthanum contained in the glaze layer 20 and other glaze materials described later constituting the glaze layer 20 is 100% by weight, the content of lanthanum is 5% by weight or more in terms of lanthanum oxide (La2O3). By containing lanthanum in an amount of 5% by weight or more in terms of lanthanum oxide (La2O3), the glaze layer 20 can exhibit practical antiviral properties. Needless to say, it is possible to convert the amount of lanthanum oxide into the weight percentage of lanthanum stoichiometrically.

[0023] In another aspect of the present invention, the content of lanthanum contained in the glaze layer 20 can also be quantified by analyzing the glaze layer 20 by X-ray fluorescence analysis (XRF). In the present invention, using a scanning X-ray fluorescence analyzer (Rigaku ZSX PrimusIV (manufactured by Rigaku Corporation)), the atomic abundance (mass%) of lanthanum contained in the glaze layer 20 is determined under the following measurement conditions and analysis conditions. (Measurement conditions) Tube voltage: 60 kV Tube current: 50 mA Measurement depth: several tens of μm (about 0 to 50 μm) Measurement area: Φ20 mm (Analysis conditions) La detection line: La Lα (alpha) line, 2θ = 82.88 Spectrometer crystal: LiF(200) Detector: SC Incidentally, since the measurement limit of the above scanning-type fluorescent X-ray analyzer is a region with a depth of about 50 μm in the direction of the pottery body from the surface (0 μm) of the glaze layer 20 (the direction of the arrow shown in FIG. 1), in the present invention, the quantification of lanthanum using the above scanning-type fluorescent X-ray analyzer is based on the content (% by mass) of lanthanum in the depth region of about 50 μm from the surface of the glaze layer 20, and is used to identify the glaze layer 20.

[0024] In this embodiment, the content of lanthanum contained in the region with a depth of about 50 μm in the direction of the pottery body from the surface (0 μm) of the glaze layer 20 is 9% by mass or more in terms of the atomic abundance measured by the fluorescent X-ray analysis method (XRF). By the above region containing lanthanum with an atomic abundance of 9% by mass or more measured by the fluorescent X-ray analysis method (XRF), the glaze layer 20 can exhibit practical antiviral properties.

[0025] The atomic abundance of lanthanum measured by the fluorescent X-ray analysis method (XRF) has the advantage that it can accurately measure the content of lanthanum contained in the region with a depth of about 50 μm in the direction of the pottery body from the surface (0 μm) of the glaze layer 20, that is, in the vicinity of the surface of the glaze layer 20. That is, the content of lanthanum in terms of lanthanum oxide described above represents the content ratio (percentage) of lanthanum in the entire glaze layer 20, and the content of lanthanum measured by the fluorescent X-ray analysis method (XRF) accurately represents the content ratio of lanthanum in the vicinity of the surface of the glaze layer 20 pinpointedly. In addition, the content of lanthanum measured by the fluorescent X-ray analysis method (XRF) helps to accurately grasp the addition amounts of various compounds such as oxides and chlorides of lanthanum as starting materials for antiviral agents based on stoichiometry.

[0026] Incidentally, in this specification, the glaze layer 20 containing "lanthanum in a specific amount or more" means that the glaze layer 20 contains lanthanum in an amount of 5% by weight or more in terms of lanthanum oxide (lanthanum oxide: La2O3), or that the region with a depth of about 50 μm in the direction of the pottery body from the surface (0 μm) of the glaze layer 20 measured by the fluorescent X-ray analysis method (XRF) contains lanthanum with an atomic abundance of 9% by mass or more.

[0027] A specific amount or more of lanthanum contained in the glaze layer 20 efficiently inactivates the virus attached to the surface of the glaze layer. According to a preferred embodiment of the present invention, lanthanum (La 3+ ) eluted on the surface of the glaze layer and ionized in a chemically stable state efficiently inactivates the virus attached to the surface of the glaze layer. In this way, the glaze layer 20 can exhibit practical antiviral properties.

[0028] In the present invention, the antiviral property of the sanitary ware provided with the glaze layer 20 containing a specific amount or more of lanthanum can be represented by using the antiviral activity value against bacteriophage Qβ as an index. The antiviral activity value can be determined, for example, by the following test method in accordance with ISO 21702.

[0029] <Antiviral test method> · Drop 0.4 mL of the virus solution onto the test pieces (test pieces of sanitary ware provided with a glaze layer containing a specific amount or more of lanthanum, and a control (test piece of sanitary ware provided with a glaze layer not containing an antiviral agent)), and cover with a film. · Leave the test pieces standing at 25°C for 24 hours. · After standing, wash out and collect the virus on the test pieces, and then measure the virus infectious titer. · Calculate the antiviral activity value according to the following formula and evaluate the antiviral property. R = Ut - At R: Antiviral activity value Ut: Common logarithm of the virus infectious titer (PFU / cm 2 ) after 24 hours of standing of the control At: Common logarithm of the virus infectious titer (PFU / cm 2 ) after 24 hours of standing of the test piece of sanitary ware provided with a glaze layer containing a specific amount or more of lanthanum

[0030] In the present invention, the antiviral activity of the sanitary pottery provided with the glaze layer 20 containing a specific amount or more of lanthanum can also be expressed by using, as an index, the antiviral activity value (V) determined according to the visible light B condition of JIS R1756 in a bright place. Specifically, an antiviral test is carried out using bacteriophage Qβ in accordance with the visible light B condition of JIS R1756. Using a 20W white fluorescent lamp (manufactured by Toshiba Lighting & Technology Corporation, "Neo Line" FL20S·W) as a light source, visible light of 380 nm or more is irradiated at an illuminance of 500 lux through an ultraviolet cut filter (manufactured by Nitto Denko Corporation, N-169). The illuminance is measured using an illuminance meter: IM-5 manufactured by Topcon Corporation. With the irradiation time of visible light being 4 hours, the antiviral activity value (V) in the bright place can be calculated by the following formula.

[0031] Antiviral activity value: V = Log 10 (UV / TV) TV: Bacteriophage infection titer (pfu) of the sanitary pottery provided with the glaze layer containing a specific amount or more of lanthanum after light irradiation UV: Bacteriophage infection titer (pfu) per control after light irradiation Note that, as a control, sanitary pottery provided with a glaze layer not containing an antiviral agent is used.

[0032] In the present invention, the glaze layer 20 containing a specific amount or more of lanthanum has an antiviral activity value of 2 to 6. An antiviral activity value of 2 or more satisfies the practical antiviral performance standard in sanitary pottery.

[0033] In the present invention, in order to exhibit practical virus activity, the elution amount of lanthanum on the surface of the glaze layer 20 is preferably at least about 0.05 ppm. Further, in a preferred embodiment of the present invention, the elution amount of lanthanum is about 1 to 2% of the content of lanthanum contained in a region with a depth of 10 nm in the direction from the surface of the glaze layer to the pottery body (the direction of the arrow shown in FIG. 1).

[0034] Incidentally, from the perspective of only practical antiviral properties, the upper limit of the content of lanthanum contained in the glaze layer 20 is not particularly limited. However, since the glaze layer 20 constituting the outermost layer of the sanitary ware preferably satisfies the surface properties desired for the sanitary ware, in the present invention, it is preferable to control the upper limit of the content of lanthanum contained in the glaze layer 20. Details will be described later.

[0035] Other glaze materials The glaze layer 20 contains, together with a specific amount or more of lanthanum, materials usually used in glazes, such as SiO2, Al2O3, divalent metal oxides, and monovalent metal oxides. According to a preferred embodiment of the present invention, the weight percentage of SiO2 with respect to the glass component is 52 to 76%, the weight percentage of Al2O3 with respect to the glass component is 6 to 14%, the weight percentage of the divalent metal oxide with respect to the glass component is 11.4 to 27.6%, and the weight percentage of the monovalent metal oxide with respect to the glass component is 1.5 to 6.5%.

[0036] The glaze layer 20 has SiO2, Al2O3, divalent metal oxides, and monovalent metal oxides as main components, but may also contain Fe2O3, TiO2, V2O5, etc. As the divalent metal oxide, alkaline earth metal oxides such as CaO and MgO, ZnO, CuO, etc. can be used. As the monovalent metal oxide, Na2O, K2O, Li2O, etc. can be used.

[0037] In the present invention, the preferred composition of other glaze materials other than a specific amount or more of lanthanum is as shown in Table 1 below, for example.

[0038]

Table 1

[0039] Existence state of lanthanum (antiviral agent) in the glaze layer 20 In the present invention, it is preferable that lanthanum exists in an amorphous state at least on the surface of the glaze layer 20. When lanthanum exists in an amorphous state on the surface of the glaze layer 20, lanthanum can be efficiently ionized and eluted on the surface of the glaze layer, and it becomes possible to efficiently inactivate the virus adhering to the surface of the glaze layer. Further, since it exists in an amorphous state, the influence on the surface properties of the glaze layer surface can be suppressed.

[0040] According to a preferred embodiment of the present invention, by setting the content of lanthanum contained in the glaze layer 20 to less than 14.2% by weight in terms of lanthanum oxide (La2O3), or by setting the content of lanthanum contained in the region having a depth of about 50 μm from the surface (0 μm) of the glaze layer 20 in the direction of the pottery body to less than 21.2% by mass in terms of the atomic abundance measured by X-ray fluorescence analysis (XRF), precipitation of crystals (for example, considered to be a composite crystal of La and Si) in the glaze layer 20 can be suppressed.

[0041] According to a more preferred embodiment of the present invention, by setting the content of lanthanum contained in the glaze layer 20 to less than 11.5% by weight in terms of lanthanum oxide (La2O3), or by setting the content of lanthanum contained in the region having a depth of about 50 μm from the surface (0 μm) of the glaze layer 20 in the direction of the pottery body to less than 18.9% by mass in terms of the atomic abundance measured by X-ray fluorescence analysis (XRF), lanthanum can be made to exist in an amorphous state on the surface of the glaze layer 20. In other words, lanthanum can be included in the amorphous region of the glaze layer 20. In such a state, it becomes possible to bring the surface properties of the glaze layer 20 closer to those desired as described later.

[0042] In the present invention, it is more preferable that lanthanum exists in a vitrified state at least on the surface of the glaze layer 20. Since lanthanum exists in a vitrified state on the surface of the glaze layer 20, lanthanum can be more efficiently ionized and eluted by the surface of the glaze layer, and it becomes possible to more efficiently inactivate the virus adhering to the surface of the glaze layer. Further, since it exists in a vitrified state, the influence on the surface properties of the surface of the glaze layer can be suppressed, and the surface properties of the glaze layer 20 can be made closer to the desired ones as described later.

[0043] The fact that lanthanum exists in an amorphous state, preferably in a vitrified state, at least on the surface of the glaze layer 20 can be confirmed by performing XRD measurement on the surface of the glaze layer 20. For example, using an XRD device: <X’Pert PRO> manufactured by PANalytical, measurement is performed under the following conditions, and it is confirmed that no peak is observed, indicating that it is not crystalline, that is, it is in an amorphous state, preferably in a vitrified state. XRD Measurement Conditions Measurement Range: 3° to 60° Scan Rate: 4° / min Applied Voltage: 45V, Applied Current: 40mA

[0044] In the present invention, it is even more preferable that lanthanum is spinodally phase-separated at least on the surface of the glaze layer 20. In the present invention, "spinodal phase separation" generally refers to a state in which precipitation of particles due to crystallization in the glaze layer is suppressed. As a result, a specific lanthanoid is likely to stably elute on the surface of the glaze layer, and even when a specific lanthanoid exists on the surface of the glaze layer, the influence on the surface properties of the glaze layer is further suppressed. In particular, regarding elution, when lanthanum is spinodally phase-separated on the surface of the glaze layer 20, lanthanum can be stably ionized and eluted from the surface of the glaze layer, and it becomes possible to more efficiently inactivate the virus adhering to the surface of the glaze layer, and high antiviral properties can be exhibited.

[0045] As will be described later, the spinodal phase separation of lanthanum is realized by integrally firing the ceramic body 10 and the glaze forming the glaze layer 20 once and then cooling them. Specifically, by integrally firing and cooling the ceramic body 10 and the glaze for forming the glaze layer 20 once, it becomes possible to induce the phase separation phenomenon of glass. The phase separation of glass refers to the phenomenon in which a single-phase glass separates into a plurality of phases. When a glass composed of a plurality of components exists as a uniform liquid phase (glass melt), as the temperature decreases, there is a region where the free energy is lower in the two-phase mixture state than in the single-phase state. The glass melt placed in such a region separates into two phases because it becomes a thermodynamically stable state.

[0046] In the present invention, a glaze composed of a plurality of components such as SiO2, metal oxides, and lanthanum oxides becomes a uniform (single) glass liquid phase (glass melt) upon firing. By cooling this glass melt to a temperature below the liquidus line in the phase equilibrium diagram of the glass, it is placed in a metastable immiscible region. In the metastable immiscible region, there are (i) a binodal region where the glass melt phase-separates by a nucleation-growth mechanism in which nuclei are generated and grow, and (ii) a spinodal region where the glass melt becomes thermodynamically unstable and phase-separates (spinodal decomposition mechanism) without nucleation. In the binodal region, one of the two phases formed by phase separation is dispersed in spherical particles that are not intertwined with the other, and in the spinodal region, one of the two phases formed by phase separation is dispersed in a non-spherical shape with a high degree of entanglement with the other. Theoretically, lanthanum is considered to be able to take both the spinodal phase-separated state and the binodal phase-separated state in the glaze layer. In the present invention, by integrally firing and cooling the ceramic substrate 10 and the glaze for forming the glaze layer 20, although the details of the mechanism are not clear, lanthanum can be richly present near the surface of the glaze layer, and the proportion of lanthanum present near the surface of the glaze layer in the spinodal phase-separated state can be made higher than the proportion in the binodal phase-separated state. As will be described later, this has been confirmed by experiments. For example, as shown in FIGS. 3A, 3B, and 6A, near the surface of the glaze layer 20, lanthanum is richly present, and this lanthanum is present in the spinodal phase-separated state.

[0047] In the mode where lanthanum exists in a spinodal phase separation state near the surface of the glaze layer, the state where the lanthanum-rich phase is intertwined with the phase that is not rich in lanthanum (-Si-O- structure), or the state where the lanthanum-rich part is more intertwined with the part that is not rich in lanthanum (i.e., uniformly exists with higher resolution), etc. are considered to be included in the state where the lanthanum-rich part in the glass matrix structure on the surface of the glaze layer forms an intertwined structure as a whole in cooperation with other parts. When lanthanum exists near the surface of the glaze layer in such a state, it is considered that lanthanum can be eluted macroscopically uniformly from the surface of the glaze layer or the elution is promoted, and as a result, high antiviral properties are exhibited.

[0048] Note that in the present invention, it is only necessary that the region where lanthanum undergoes spinodal phase separation exists on the surface of the glaze layer 20 within the range where the effects of the present invention are achieved. Within the range that does not inhibit the effects of the present invention, for example, due to inevitable circumstances during the process of manufacturing the glaze layer 20, etc., the present invention does not exclude the mode where the region where lanthanum undergoes binodal phase separation exists at a lower ratio compared to the region where lanthanum undergoes spinodal phase separation.

[0049] In addition, since lanthanum exists in a spinodal phase separation state on the surface of the glaze layer 20, it exhibits white due to scattering at the interface between the two phases, and it becomes possible to realize a glaze layer surface with excellent imaging properties described later. Moreover, since lanthanum exists in a spinodal phase separation state on the surface of the glaze layer 20, a lanthanum-rich phase uniformly exists on the surface, so that lanthanum can be stably eluted, and as a result, high antiviral properties can be provided.

[0050] Surface properties Average roughness (Ra) In the present invention, it is preferable that the surface roughness (Ra) of the glaze layer 20 is less than 0.07 μm. When the surface roughness (Ra) is less than 0.07 μm, it becomes difficult for urinary calculi, mold, stains, and other dirt to adhere to the sanitary ware, and even if they adhere, they can be easily removed by a weak water flow. As a result, the surface of the sanitary ware can be maintained in a clean state for a long period without requiring frequent cleaning operations.

[0051] In a preferred embodiment of the present invention, by setting the content of lanthanum contained in the glaze layer 20 to less than 10% by weight in terms of lanthanum oxide (La2O3), it is possible to make the surface roughness (Ra) of the glaze layer 20 less than 0.07 μm. In another preferred embodiment of the present invention, by setting the content of lanthanum contained in the region with a depth of about 50 μm from the surface (0 μm) of the glaze layer 20 in the direction of the pottery body to less than 18.5% by mass in terms of the atomic abundance measured by X-ray fluorescence analysis (XRF), it is possible to make the surface roughness (Ra) of the glaze layer 20 less than 0.07 μm. Therefore, in the present invention, by setting the content of lanthanum contained in the glaze layer 20 to 5% by weight or more and less than 10% by weight in terms of lanthanum oxide (La2O3), or by setting the content of lanthanum contained in the region with a depth of about 50 μm from the surface (0 μm) of the glaze layer 20 in the direction of the pottery body to 9% by mass or more and less than 18.5% by mass in terms of the atomic abundance measured by X-ray fluorescence analysis (XRF), it is possible to realize the sanitary ware 1 provided with the glaze layer 20 having practical antiviral properties and excellent stain non-adhesion and easy removability (the property of being difficult to adhere and easy to fall off).

[0052] According to a preferred embodiment of the present invention, Ra is 0.068 μm or less, more preferably 0.05 μm or less, and even more preferably 0.04 μm or less. In this case, the stain non-adhesion and easy removability are further improved.

[0053] In the present invention, "surface roughness (Ra)" refers to the center line average roughness (μm) measured by a stylus type surface roughness measuring device (JIS-B0651) and defined by JIS-B0601 (1994).

[0054] DOI value In the present invention, it is preferable that the DOI value of the glaze layer 20 measured by a wave scan DOI measuring device on its surface is 80 or more. In the present invention, the "DOI value" refers to the DOI value measured by a wave scan DOI measuring device, for example, Wave-ScanDIO (orange peel measuring device) manufactured by BYK Gardner (Germany). In the present invention, the DOI value is used as an index representing the imageability of the surface of the glaze layer provided in the sanitary pottery according to the present invention. "Imageability" represents the sharpness of the reflection of an object, and this appearance quality is determined by the difference in light reflection due to the surface shape of the glaze layer and is recognized by human vision.

[0055] When the DOI value of the surface of the glaze layer 20 is 80 or more, it gives an impression of excellent imageability to those who see it, and as a result, the sanitary pottery has a high-class feeling. In addition, good imageability makes the dirt attached to the sanitary pottery more noticeable and enables early confirmation of the attachment of dirt such as viruses, etc., so that it is possible to suppress the situation where the attachment of dirt, etc. is left unattended. According to a preferred embodiment of the present invention, the DOI value of the surface of the glaze layer 20 is 85 or more.

[0056] The above wave scan DOI measuring device scans by moving a laser point light source on the surface of the glaze layer, and like the human eye, measures the light and dark of the reflected light one by one at determined intervals, detects the optical profile of the surface of the glaze layer, and further analyzes the spectrum of this optical profile through a frequency filter to analyze the structure of the surface of the glaze layer. The microwave scan by the above device irradiates the laser light at an angle of 60° inclined from the perpendicular to the surface of the glaze layer, and the detector measures the reflected light at the same angle opposite to the perpendicular. The characteristic spectrum of the above device is as follows. du: Wavelength below 0.1 mm Wa: Wavelength 0.1 - 0.3 mm Wb: Wavelength 0.3 - 1 mm Wc: Wavelength 1 - 3 mm Wd: Wavelength 3 - 10 mm We: Wavelength 10 - 30 mm Sw: Wavelength 0.3 - 1.2 mm Lw: Wavelength 1.2 - 12 mm DOI: Wavelength below 0.3 mm Here, DOI is a parameter consisting of du, Wa, and Wb, and is expressed as DOI = f(du, Wa, Wb).

[0057] Color difference: ΔE* value In the present invention, the glaze layer 20 preferably has a color difference: ΔE* value of 1.20 or less on its surface. By having a ΔE* value of 1.20 or less on the surface of the glaze layer 20, a sanitary ceramic ware with excellent light resistance can be obtained. The ΔE* value is measured in accordance with the sunshine carbon arc lamp method described in Section 8, Chapter 9 of JIS K5400 (1990), using a sunshine carbon arc lamp weather resistance tester (manufactured by Suga Test Instruments Co., Ltd., S - 300). The test time is set to 8 hours, and the L*, a*, and b* values of the photocatalyst coating before and after the test are measured by the SCE method, and the color difference: ΔE* = [[(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 1 / 2 is obtained. As the color difference meter, a color and color difference meter (manufactured by Konica Minolta, CR - 400) can be used. The color difference: ΔE* value on the surface of the glaze layer 20 is more preferably 0.8 or less, and even more preferably 0.7 or less.

[0058] Film thickness In the present invention, the film thickness of the glaze layer 20 is preferably 50 - 1200 μm, more preferably 100 - 800 μm, and even more preferably 150 μm - 400 μm. With a glaze layer 20 having such a thickness, the above-described surface properties can be realized.

[0059] ​Manufacturing method The sanitary pottery according to the present invention can be preferably manufactured by the following method.

[0060] First, a pottery body 10 is prepared. The pottery body 10 may be appropriately formed from a conventionally known sanitary pottery body slurry prepared using silica sand, pottery stone, clay, etc. as raw materials.

[0061] A glaze slurry for forming the glaze layer 20, that is, a glaze slurry containing a lanthanum compound containing 5% by weight or more of lanthanum in terms of lanthanum oxide (La2O3) as a raw material of the antiviral agent and other glaze materials is prepared. The composition of the glaze materials other than the above lanthanum compound is, for example, as described in Table 1 above. Further, as the lanthanum compound, for example, those having a boiling point of 1000 ° C or higher, more preferably those having a boiling point of 1300 ° C or higher, and those having a melting point of 1000 ° C or higher can be used. Even more preferably, it has a melting point of 1000 ° C or higher and is a water-insoluble compound.

[0062] The glaze slurry for forming the glaze layer 20 can be prepared, for example, as follows. Embodiment 1 A glaze material having the composition described in Table 1, water, and a dispersion medium (for example, alumina balls) are placed in a pottery pot and pulverized, for example, by a ball mill to obtain a glaze slurry precursor. To this glaze slurry precursor, a lanthanum compound containing 5% by weight or more of lanthanum in terms of lanthanum oxide (La2O3) is added, mixed, and pulverized to obtain a glaze slurry for forming the glaze layer 20. Embodiment 2 A glaze material having the composition described in Table 1 is melted at a predetermined temperature and cooled to obtain a frit raw material. To this frit raw material, a lanthanum compound containing 5% by weight or more of lanthanum in terms of lanthanum oxide (La2O3) is added, and further water, a dispersion medium, and, if necessary, other raw materials (for example, pottery stone, ZnO, etc.) are added, placed in a pottery pot, and pulverized, for example, by a ball mill to obtain a glaze slurry for forming the glaze layer 20.

[0063] According to a preferred embodiment of the present invention, in the above-described Embodiments 1 and 2, it is preferable that the average particle size of the lanthanum after pulverization and the average particle size of the glaze material after pulverization are substantially the same. For example, the average particle sizes of lanthanum and the glaze material are preferably 10 μm or less, preferably about 6 to 7 μm and substantially the same. Here, the average particle size means the so-called 50% particle size in the particle size distribution data measured by the laser diffraction method. Further, that the average particle sizes are "substantially the same" means that the ratio (the former / the latter) of the average particle size of lanthanum to the average particle size of the glaze material is within the range of 0.9 to 1.1.

[0064] By making the average particle sizes of lanthanum and the glaze material uniform in this way, spinodal phase separation of lanthanum can be performed on the surface of the glaze layer 20, and the above-described surface properties (Ra, DOI value, ΔE* value) can be realized.

[0065] Next, a glaze slurry for forming the glaze layer 20 is applied to the surface of the ceramic body 10. The application method is not particularly limited, and general methods such as spray coating and dip coating can be appropriately selected and used.

[0066] Next, the ceramic body 10 to which the glaze slurry for forming the glaze layer 20 is applied is fired. That is, the ceramic body 10 and the glaze slurry are integrally fired. The firing temperature is preferably a temperature at which the sanitary ceramic body is sintered and the glaze is softened, and further lower than the melting point of the antiviral agent. Such a firing temperature is preferably 1000°C or higher and 1300°C or lower, more preferably 1150°C or higher and 1250°C or lower. It is preferable to perform the integral firing only once. The inventors have confirmed by experiments that crystallization of lanthanum is suppressed by performing the integral firing only once. Specifically, it has been confirmed that crystals precipitate from the amorphous layer of the glaze layer when firing is performed a plurality of times, and crystals precipitate when the second firing is performed at a temperature lower than the first firing temperature.

[0067] Next, the obtained fired body is cooled. The cooling conditions are not particularly limited, and natural cooling may be used, or the temperature and time may be appropriately controlled.

[0068] The pottery body 10 and a glaze slurry prepared such that the average particle size of lanthanum and the average particle size of other glaze materials are substantially the same are integrally fired once at a temperature lower than the melting point of lanthanum and then cooled, thereby suppressing the crystallization of lanthanum, preferably vitrifying it, more preferably forming a glassy liquid phase (glass melt), even more preferably phase-separating the glass melt, and most preferably spinodal phase-separating it. As a result, a glaze layer 20 in which regions where lanthanum is spinodally phase-separated are richly present on its surface can be obtained.

Example

[0069] The present invention will be specifically described based on the following examples, but the present invention is not limited to these examples.

[0070] Fabrication of the ceramic body Using a pottery body slurry prepared from raw materials such as silica sand, feldspar, and clay, a 70 mm × 150 mm plate-shaped test piece was produced.

[0071] Preparation of the glaze slurry for forming the base glaze layer 2 kg of a glaze material having the composition shown in Table 2 below, 1 kg of water, and 4 kg of alumina balls were placed in a 6 L pottery pot, and pulverization was performed using a ball mill so that the particle size measurement result of the glaze slurry after pulverization using a laser diffraction particle size distribution analyzer was such that 65% was 10 μm or less and the 50% particle size was about 6.5 μm, thereby obtaining a glaze slurry for forming a base glaze layer.

[0072]

Table 2

[0073] Preparation of the glaze slurry for forming the antiviral glaze layer 2 kg of glaze material composed of the composition described in Table 3 below, 1 kg of water, and 4 kg of alumina balls were placed in a 6-L pottery pot. The particle size measurement results of the glaze slurry after grinding using a laser diffraction particle size distribution analyzer showed that 65% was 10 μm or less and the 50% particle size (D50) was 6.5 μm. Grinding was performed using a ball mill to obtain a glaze slurry precursor. Different contents of lanthanum oxide (La2O3) described in Table 4 were added to this glaze slurry precursor (that is, lanthanoid oxides at each concentration described in Table 4 were added based on 100% by weight of the total content of the above glaze material), mixed, and grinding was performed using a ball mill so that 65% was 10 μm or less and the 50% particle size (D50) was 6.5 μm. After grinding, antiviral glaze slurries for sanitary ceramics of Examples 1 to 15 were prepared.

[0074]

Table 3

[0075] Fabrication of the sanitary ware Each of the antiviral glaze slurries prepared as described above was applied to the above pottery substrate test piece by the spray coating method. Then, firing was integrally performed once at 1200 °C in a kettle to produce sanitary ceramics of Examples 1 to 15.

[0076] Evaluation The following evaluations were performed on the sanitary ceramics of Examples 1 to 15.

[0077] Content of lanthanum The amount (weight %) of lanthanum converted to lanthanum oxide (La2O3) contained in the glaze layer of the sanitary ceramics of Examples 1 to 15 and the atomic abundance (mass %) measured by XRF were as shown in Table 4. The lanthanum content (wt%) based on the amount of lanthanum oxide (La2O3) equivalent in each sanitary ware shown in Table 4, for example, for the sanitary ware of Example 4, was calculated as the percentage of lanthanum oxide (5 wt%) with respect to the total of 100 wt% of the glaze material shown in Table 3 and 5 wt% of lanthanum oxide (105 wt%), i.e., 5 wt% / (100 wt% + 5 wt%)×100 ≒ 4.8%. The same applies to the other Examples 1 - 3 and 4 - 15. When comparing the lanthanum content (wt%) based on the amount of lanthanum oxide (La2O3) equivalent in each sanitary ware with the lanthanum content (mass%) measured by XRF, it was confirmed that the latter was higher. This indicates that the lanthanum content near the surface of the antiviral glaze layer is higher than the lanthanum content contained in the entire antiviral glaze layer. That is, it shows that lanthanum is concentrated near the surface of the antiviral glaze layer. Therefore, according to the present invention, lanthanum (antiviral agent) can be concentrated and present near the surface of the glaze layer, and as a result, good antiviral properties can be exhibited. Also, according to the present invention, even a small amount of lanthanum can be concentrated near the surface of the glaze layer, so that good antiviral properties can be efficiently exhibited, and since the amount of lanthanum is small, it does not affect the Si - O structure of the glaze layer, that is, it is possible to realize a sanitary ware that maintains excellent surface properties. Regarding the atomic abundance (mass%) of lanthanum contained in the glaze layer of the sanitary wares of Examples 10 and 11 measured by XRF, although the cause is not clear, it is considered to include measurement errors.

[0078] Relationship among the content of the antiviral agent (lanthanum), the elution amount of the antiviral agent, and the antiviral activity value Also, the relationship among the content of the antiviral agent, the elution amount of the antiviral agent, and the antiviral activity value in the sanitary wares of Examples 1 - 15 was confirmed. Figure 4A shows the relationship between the amount of lanthanum in terms of lanthanum oxide (La2O3) (wt%) and the elution amount of lanthanum on the surface of the glaze layer (ppm). Figure 4B shows the relationship between the elution amount of lanthanum and the antiviral activity value. Figure 5A shows the relationship between the amount of lanthanum in terms of lanthanum oxide (La2O3) (wt%) and the atomic abundance (mass%) measured by XRF of lanthanum. Figure 5B shows the relationship between the atomic abundance (mass%) of lanthanum measured by XRF and the antiviral activity value. From Figures 4 and 5, it was confirmed that a proportional relationship holds between the amount of lanthanum in terms of lanthanum oxide (La2O3) (wt%) and the atomic abundance (mass%) of lanthanum measured by XRF, a proportional relationship holds between the content of lanthanum and the elution amount of lanthanum on the surface of the glaze layer, and a proportional relationship also holds between the elution amount of lanthanum and the antiviral activity value.

[0079] Antiviral property The antiviral activity value against bacteriophage Qβ was determined by the following test method in accordance with ISO 21702. · 0.4 mL of the virus solution was dropped onto the sanitary ceramics of Examples 1 to 15 and the sanitary ceramics without an antiviral agent in the glaze layer as a control, and then covered with a film. · Each sanitary ceramic was allowed to stand at 25°C for 24 hours. · After standing, the virus on each sanitary ceramic was washed out and collected, and then the virus infectivity titer was measured. · The antiviral activity value was calculated by the following formula. R = Ut - At R: Antiviral activity value Ut: Common logarithm of the virus infectivity titer (PFU / cm 2 ) after standing for 24 hours of the sanitary ceramics of the control At: Common logarithm of the virus infectivity titer (PFU / cm 2 ) after standing for 24 hours of the sanitary ceramics of Examples 1 to 15 The antiviral activity values of the sanitary ceramics of Examples 1 to 15 were as shown in Table 4.

[0080] Average roughness (Ra) Using a stylus-type surface roughness measuring device (JIS-B0651), the center line average roughness (μm) defined by JIS-B0601 (1994) was determined. The results were as shown in Table 4.

[0081] DOI value Wave scan DOI measuring device: Using a Wave-ScanDIO (orange peel measuring device) manufactured by BYK Gardner (Germany), the DOI value was measured. The results were as shown in Table 4.

[0082] From the above results of antiviral properties, Ra value, and DOI value shown in Table 4, it was confirmed that the sanitary ceramics of Examples 5 to 9, in which the content of lanthanum contained in the glaze layer is 5% by weight or more and less than 10% by weight in terms of lanthanum oxide (La2O3), or 9% by mass or more and less than 18.5% by mass in terms of the atomic abundance measured by XRF, have both practical antiviral properties and excellent stain resistance and easy removability (the property of being difficult to stain and easy to fall off).

[0083] Confirmation of the existence state of lanthanum near the surface of the glaze layer <XRD measurement> XRD device: Using <X’Pert PRO> manufactured by PANalytical, the measurement was carried out under the following conditions. XRD measurement conditions Measurement range: 3° to 60° Scan rate: 4° / min Applied voltage: 45V, applied current: 40mA The XRD patterns of the glaze layer surfaces of the sanitary ceramics of Examples 1 to 15 with different lanthanum contents were as shown in Fig. 2. Note that the % of lanthanum (La) shown in Fig. 2 represents the addition amount when the total of the glaze materials shown in Table 3, with lanthanum oxide added as a raw material, is taken as 100% by weight. In the XRD measurement of the glaze layer surface of the sanitary ceramics of Examples 1 to 12, no peaks were observed. Therefore, it was confirmed that on the surface of the antiviral glaze layer with a lanthanum content of 1.0 to 11.5% by weight in terms of lanthanum oxide (La2O3), lanthanum exists in an amorphous (non-crystalline) state or a vitrified state. On the other hand, peaks were observed in the XRD measurement of the glaze layer surface of the sanitary ceramics of Examples 13 to 15. Therefore, it was confirmed that on the surface of the antiviral glaze layer with a lanthanum content of 14.2% by weight or more in terms of lanthanum oxide (La2O3), crystals (presumed to be composite crystals of La and Si) were precipitated and lanthanum did not exist in an amorphous (non-crystalline) state or a vitrified state. Note that the maximum peak observed in the XRD pattern of Example 15 is SiO2, and the peaks observed at 2θ (10 - 15) are, in order from the left, La2Si2O7, La2Si2O7, SiO2. Also, the small peaks observed in the XRD patterns of Examples 1 and 4 are noise.

[0084] <SEM Observation> Among the sanitary ceramics of Examples 1 to 15, the state of existence of lanthanum in the vicinity of the surface of the glaze layer of the sanitary ceramics of Example 4 was observed by SEM. The SEM observation was carried out using the apparatus: S4800 (manufactured by Hitachi High-Technologies), conditions: magnification 50,000 times, applied voltage 2.0 kV, applied current 20 mA (2.0 mm × 50.0 k SE (U, LA100)). The SEM images are shown in Fig. 3. Fig. 3A is the surface SEM image of the glaze layer, and Fig. 3B is the cross-sectional SEM image of the glaze layer. In both Fig. 3A and Fig. 3B, the white part indicates the existence of lanthanum, and the black part indicates the Si - O structure. In Fig. 3B, the part that looks like a boundary line shows that the white part indicates a state where lanthanum is richly present. Since the image area above the white part is the air area, it is outside the observation target. From Figure 3B, in the glaze layer of the sanitary ware of Example 4, the lanthanum content was about 4.8% by weight in terms of lanthanum oxide (La2O3), the atomic abundance measured by XRF was 8.3% by mass, and from the cross-sectional image of Figure 3B, it was confirmed that lanthanum was richly present on the surface of the glaze layer. Further, this lanthanum present on the surface of the glaze layer was spinodally phase-separated, and it was confirmed that the spinodal phase-separation amount was rich.

[0085] Light resistance (discoloration suppression ability) In accordance with JIS K5400-9-8 Sunshine Carbon Arc Method, a weather resistance test was carried out using a Sunshine Carbon Arc Lamp Type Weather Resistance Tester (manufactured by Atlas Corporation, USA). The test time was set to 8 hours, and the L*, a*, and b* values of the photocatalytic coating body before and after the test were colorimetrically measured by the SCE method, and the color difference: ΔE* = [(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 1 / 2 was determined. As the color difference meter, a Color and Color Difference Meter (manufactured by Konica Minolta, CR-400) was used. The results were as shown in Table 4.

[0086]

Table 4

[0087] Confirmation of the relationship between the firing conditions, the spinodal phase separation amount, and the antiviral activity value The addition amount of lanthanum oxide was 10% by weight, and the antiviral glaze slurry prepared according to the above preparation example was applied to the above pottery substrate test piece by the spray coating method. Then, it was fired in a kettle under the following conditions 1 to 3 to produce three types of sanitary wares A to C. Sanitary ware A: Firing condition 1 (firing temperature: 1200 °C, total firing time: 10 hours) Sanitary ware B: Firing condition 2 (firing temperature: 1200 °C, total firing time: 15 hours) Sanitary ware C: Firing condition 3 (firing temperature: 1200 °C, total firing time: 20 hours) ​The antiviral activity values of sanitary wares A to C were as shown in Table 5 below. Also, the state of existence of lanthanum near the surface of the antiviral glaze layer of sanitary wares A to C was as shown in FIGS. 6A to C.

[0088] [Table 5] From Table 5 and FIGS. 6A to C, under the condition that the addition amount of lanthanum oxide and the firing temperature were the same, sanitary ware A manufactured by setting a short firing time had high antiviral properties, and furthermore, lanthanum underwent spinodal phase separation near the surface of the glaze layer 20, and it was confirmed that the phase separation region was rich. On the other hand, sanitary ware B with a long set time had a mixture of binodal phase separation and spinodal phase separation, had lower antiviral properties than sanitary ware A, and furthermore, sanitary ware C with an even longer set time was confirmed to have lower antiviral properties than sanitary wares A and B. In addition, as described above, those skilled in the art can adopt various methods to make specific lanthanoids such as lanthanum exist in the spinodal phase separation near the surface of the glaze layer 20, other than adjusting the particle size and firing time. [Explanation of Reference Numerals]

[0089] 1 Sanitary ware, 10 Ceramic body, 20 (Top) Glaze layer, 30 Base glaze layer

Claims

1. A sanitary pottery comprising a pottery body and a glaze layer formed on the surface of the pottery body, The glaze layer contains, as an antiviral agent, lanthanum in an amount of 5% by weight or more and less than 14.2% by weight in terms of lanthanum oxide (La ２ O ３ ). wherein the antiviral agent is present in an amorphous state at least on the surface of the glaze layer, characterized in that it is a sanitary pottery.

2. A sanitary pottery comprising a pottery body and a glaze layer formed on the surface of the pottery body, wherein the glaze layer contains lanthanum as an antiviral agent in an atomic abundance of 9% by mass or more and less than 21.2% by mass as measured by X-ray fluorescence analysis (XRF), wherein the antiviral agent is present in an amorphous state at least on the surface of the glaze layer, characterized in that it is a sanitary pottery.

3. The sanitary pottery according to claim 1 or 2, wherein the surface roughness (Ra) of the glaze layer is 0.07 μm or less.

4. The glaze layer contains less than 10% by weight of lanthanum in terms of lanthanum oxide (La ２ O ３ ) as an antiviral agent. The sanitary pottery according to claim 3.

5. The sanitary pottery according to claim 3, wherein the glaze layer contains lanthanum as an antiviral agent in an atomic abundance of less than 18.5% by mass as measured by X-ray fluorescence analysis (XRF).

6. The sanitary pottery according to any one of claims 1 to 5, wherein the DOI value of the surface of the glaze layer measured by a wave scan DOI measuring device is 80 or more.

7. The sanitary pottery according to any one of claims 1 to 6, wherein the antiviral agent is spinodal phase-separated at least on the surface of the glaze layer.

8. The sanitary pottery according to any one of claims 1 to 7, further comprising a base glaze layer between the pottery body and the glaze layer.

9. A method for manufacturing the sanitary pottery according to any one of claims 1 to 8, comprising the steps of preparing a pottery body, A step of preparing a glaze slurry containing a lanthanum compound containing 5% by weight or more and less than 14.2% by weight of lanthanum in terms of lanthanum oxide (La ２ O ３ ), and a glaze material other than the lanthanum compound; applying the glaze slurry to the surface of the pottery body, firing the pottery body to which the glaze slurry has been applied to form a glaze layer, characterized by including at least these steps.

10. The method according to claim 9, wherein the ratio (the former / the latter) of the average particle size of lanthanum to the average particle size of the glaze material is in the range of 0.9 to 1.

1.

11. The method according to any one of claims 9 to 10, further comprising the step of forming a base glaze layer on the surface of the pottery body, and applying the glaze slurry to the surface of the base glaze layer.

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