Sanitary ware with matte surface

Abstract

The invention discloses sanitary ware with a matte surface, which has a mild and steady texture. Specifically, the sanitary pottery according to the present invention is provided with a pottery blank and a glaze layer on the surface thereof, and is characterized in that the surface (1) of the glaze layer has a 20-degree glossiness of 5 or less, a 60-degree glossiness of 20 or less, and a 85-degree glossiness of 30 or less, and (2) has a surface roughness Ra of 1.0 [mu] m or more, so that an observer can be impressed with a mild and steady impression different from that of a conventional matte surface. Thus, the appearance (designability) of the product can be improved, the texture of the wall and the appliance in the same space can be coordinated, the diversity of the design can be expanded, for example, the design space integrated with the surroundings can be provided, and the product value can be improved.

Description

Technical Field

[0001] This invention relates to a sanitary ceramic with a matte surface, and more specifically, to a sanitary ceramic with a matte surface possessing an excellent warm and calming texture. Background Technology

[0002] Sanitary ware typically has a glossy finish, evoking a sense of luxury and cleanliness. Conversely, matte sanitary ware, which has a matte finish, is more popular in the market. Using a matte finish enhances the product's appearance (design appeal) and allows it to coordinate with the textures of walls and other appliances in the same space, expanding design possibilities.

[0003] The matte finish of sanitary ware is achieved primarily by creating unevenness on the surface to scatter light. This unevenness can be achieved through the composition of the glaze or by sandblasting the surface.

[0004] As glazes for achieving a matte finish, Japanese Patent Application Publication No. 2012-046364 (Patent Document 1) and Japanese Patent Application Publication No. 2023-034495 (Patent Document 2) disclose glazes capable of precipitating crystalline particles during firing to form a matte surface. Furthermore, Japanese Patent Application Publication No. 2018-104272 (Patent Document 3) and Japanese Patent Application Publication No. 2020-147492 (Patent Document 4) disclose methods for achieving a matte finish by sandblasting the surface.

[0005] While matte-finish sanitary ware has been well-received in the market, there remains a need for further improvement in matte finishes. For example, even on matte surfaces, the glaze layer has a glassy layer, which tends to produce glare, making the reduction of this glare a key area for improvement. However, there is a lack of insight into what metrics should be used to evaluate matte texture in a way that would be more aesthetically pleasing to users.

[0006] On the other hand, for example, in the case of a toilet, a type of sanitary ceramic, even if the surface is matte, a stain-resistant glaze layer is formed in the basin-shaped area that receives waste. For instance, Japanese Patent Application Publication No. 2012-046364 (Patent Document 1) and Japanese Patent Application Publication No. 2023-034495 (Patent Document 2) propose a good matte glaze layer, and it is also possible to form such a matte glaze layer on the entire surface of the sanitary ceramic. However, it is preferable that the basin surface of the toilet and urinal has a stain-resistant surface different from that of the present invention, and it is preferable that, in addition to the basin surface, specifically on the skirt, the inner edge, the tank body, the tank lid, etc., a glaze layer with the aforementioned surface characteristics is formed. By providing such two glaze layers, a boundary is created between the matte glaze surface and the stain-resistant glaze surface. Proposals have also been made to ensure that this boundary does not impair the appearance and design of the toilet. For example, Japanese Patent Application Publication No. 2022-062798 (Patent Document 5) describes a method that makes it difficult to distinguish the differences between two properties by coating two layers adjacent to each other in a manner that does not overlap.

[0007] Patent documents Patent Document 1: Japanese Patent Application Publication No. 2012-046364 Patent Document 2: Japanese Patent Application Publication No. 2023-034495 Patent Document 3: Japanese Patent Application Publication No. 2018-104272 Patent Document 4: Japanese Patent Application Publication No. 2020-147492 Patent Document 5: Japanese Patent Application Publication No. 2022-062798 Summary of the Invention

[0008] The inventors have achieved a matte glaze surface with a warm, calming texture. Specifically, they discovered that a combination of gloss, color, and surface roughness of the glaze layer can create an impression on the observer that differs from existing matte surfaces. This invention is based on this discovery.

[0009] Therefore, the technical problem to be solved by the present invention is to provide a sanitary ceramic with an improved matte glazed surface.

[0010] Furthermore, when it is desired to separately form two glaze layers with different properties on a sanitary ceramic piece, methods exist, such as Patent Document 5, for separately coating these two surfaces. On the other hand, methods also exist for overlapping and separately coating a portion of an area where one glaze layer is formed below and the other is formed above it. Here, when it is desired to form a matte glaze layer on the sanitary ceramic blank, and then form a stain-resistant or glossy glaze layer thereon, unlike the case of overlapping and separately coating a colored glaze layer other than matte, the boundary line between the two surfaces is distinct, and the difference in appearance between the two surfaces is significant. To the knowledge of the inventors, such an aesthetic disharmony has not been previously identified as a problem, nor have solutions been disclosed or implied.

[0011] The inventors have discovered that, on sanitary ceramics, by overlapping a stain-resistant glaze layer on top of a matte glaze layer in areas requiring stain resistance, two areas—one matte and one stain-resistant—can be formed. Furthermore, by controlling the properties of the two layers to achieve specific characteristics, their boundaries can be made less distinct. For example, it has been found that by controlling gloss, color difference, and L-value, the boundaries can be made less noticeable. This invention is based on this discovery.

[0012] Therefore, the technical problem to be solved by the present invention is to provide a sanitary ceramic with a matte surface and a stain-resistant surface, and with indistinct boundaries.

[0013] Furthermore, the sanitary pottery of the present invention comprises a pottery blank and a glaze layer on its surface, characterized in that the surface of the glaze layer has the following characteristics. (1) 20° gloss level is below 5, 60° gloss level is below 20, and 85° gloss level is below 30. (2) The surface roughness Ra is 1.0 μm or more.

[0014] According to the present invention, a sanitary ceramic with a matte surface possessing a warm and calming texture can be provided. By adopting this matte finish, which gives the observer a different impression from existing matte surfaces, the appearance (design) of the product can be improved. In addition, it can coordinate with the texture of walls and other utensils in the same space, expand the diversity of design, for example, create a design space that is integrated with the surroundings, and enhance the product's value.

[0015] According to the present invention, a sanitary ceramic ware with a matte surface and a stain-resistant surface, and whose boundaries are not clearly defined, can be provided. Since the transition between the first glaze layer and the second glaze layer, i.e., the boundary, is not obvious, it will not give the observer a strong sense of disharmony. Therefore, it will not damage the overall appearance, texture, impression, etc. of the sanitary ceramic ware, and can give the areas that need stain resistance the corresponding properties. Attached Figure Description

[0016] Figure 1 This is a SEM image of the glaze surface of Example A1. Figure 2 This is a SEM image of the glaze surface of Example A2. Figure 3 This is a SEM image of the glaze surface of Example A3. Figure 4 This is a SEM image of the glaze surface of Comparative Example A1. Figure 5 This is a SEM image of the glaze surface of Comparative Example A2. Figure 6 This is a SEM image of the glaze surface of Comparative Example A3. Figure 7 This is a SEM image of the glaze surface of Example B1. Figure 8 This is a SEM image of the glaze surface of Comparative Example B1. Figure 9 This is a SEM image of the glaze surface of Comparative Example B2. Figure 10 This is a SEM image of the glaze surface of Comparative Example B3. Figure 11 This is a SEM image of the glaze surface of Comparative Example B4. Figure 12 This is a cross-sectional schematic diagram of the third aspect of the sanitary ceramic device of the present invention, namely a flush toilet. Figure 13 This is an enlarged view of the boundary between the two surfaces of a sanitary ceramic vessel of the third embodiment of the present invention, after the first glaze layer and the second glaze layer are overlapped and coated. Detailed Implementation

[0017] definition Sanitary ceramics In this invention, "sanitary ceramics" refers to ceramic products used around toilets and washrooms, specifically toilets, urinals, toilet bowls, toilet tanks, washbasins, hand basins, etc.

[0018] gloss In this specification, surface gloss of 20°, 60°, and 85° refers to the 20° specular gloss, 60° specular gloss, and 85° surface gloss as specified in JIS Japanese Industrial Standard Z8741: Specular Gloss Measurement Method. Specifically, it refers to the gloss Gs (20°) at an incident angle of 20°, Gs (60°) at an incident angle of 60°, and Gs (85°) at an incident angle of 85°, respectively, as defined in this measurement method.

[0019] The surface characteristics of the glaze layer in sanitary ceramics The sanitary pottery of the present invention has a basic structure comprising a pottery blank and a glaze layer on its surface. Furthermore, as a surface characteristic, the glaze layer of the sanitary pottery of the present invention satisfies the following necessary conditions. (1) The gloss level of 20° is 5 or less, preferably 2 or less; the gloss level of 60° is 20 or less, preferably 15 or less; and the gloss level of 85° is 30 or less, preferably 25 or less. (2) The surface roughness Ra is 1.0 μm or more.

[0020] First preferred embodiment of the present invention The sanitary pottery of the first preferred embodiment of the present invention has a basic structure comprising a pottery blank and a glaze layer on its surface. Furthermore, as a surface characteristic, the glaze layer of the sanitary pottery of the present invention satisfies the following necessary conditions. (1) 20° gloss level is below 5, 60° gloss level is below 20, and 85° gloss level is below 30. (2) The L* value of the Lab colorimetric system is 50 or higher. (3) The surface roughness Ra is 1.0 μm or more.

[0021] The glaze layer that meets the above-mentioned necessary conditions has a matte surface, and is a matte surface with a warm and stable texture, which can suppress the so-called "glare" observed on existing matte surfaces. Although the observer's perception of "warmth" and "stability" is not easy to quantify, according to the present invention, such a matte surface can be achieved by a combination of the gloss, color, and surface roughness of the glaze layer, providing a novel matte surface.

[0022] (1) Gloss The surface of the glaze layer in the sanitary ceramic of the present invention has a gloss level of 5 or less at 20°, a gloss level of 20 or less at 60°, and a gloss level of 30 or less at 85°. According to a preferred embodiment of the present invention, the gloss level is 3.5 or less at 20°, 18 or less at 60°, and 29 or less at 85°.

[0023] (2) L* value The sanitary ceramic of the present invention has a Lab color system L* of 50 or more on the surface of the glaze layer, specifically including light colors such as beige and gray, in addition to so-called white.

[0024] (3) Surface roughness Ra The surface roughness Ra of the glaze layer in the sanitary ceramic of the present invention is 1.0 μm or more, preferably in the range of 1.1 μm or more to 1.9 μm or less. The surface roughness Ra is the arithmetic mean roughness, which can be defined in JIS Japanese Industrial Standard B 0601:2001 and measured according to that standard.

[0025] The second preferred embodiment of the present invention The sanitary pottery of the second preferred embodiment of the present invention has a basic structure comprising a pottery blank and a glaze layer on its surface. Furthermore, as a surface characteristic, the glaze layer of the sanitary pottery of the present invention satisfies the following necessary conditions. (1) 20° gloss level is below 2, 60° gloss level is below 10, and 85° gloss level is below 25. (2) The L* value of the Lab chromaticity system is less than 50. (3) The surface roughness Ra is 1.0 μm or more.

[0026] The glaze layer that meets the above-mentioned necessary conditions has a matte black surface with a warm and calm texture, which can suppress the so-called "glare" observed on existing matte surfaces. Although the observer's perception of "warmth" and "calmness" is not easy to quantify, according to the present invention, such a matte surface can be achieved by a combination of the gloss, color, and surface roughness of the glaze layer, providing a novel matte surface.

[0027] (1) Gloss The sanitary ceramic of the present invention has a glaze layer with a gloss level of 2 or less at 20°, a gloss level of 15 or less at 60°, and a gloss level of 30 or less at 85°. According to a preferred embodiment of the present invention, the gloss level is 1.8 or less at 20°, 11 or less at 60°, and 27 or less at 85°.

[0028] (2) L* value The sanitary ceramic of the present invention has a Lab color system L* of less than 50 on the surface of the glaze layer, specifically, a dark hue referred to as black.

[0029] (3) Surface roughness Ra The surface roughness Ra of the glaze layer in the sanitary ceramic of the present invention is 1.0 μm or more, preferably in the range of 1.1 μm or more to 1.9 μm or less. The surface roughness Ra is the arithmetic mean roughness, which can be defined in JIS Japanese Industrial Standard B0601:2001 and can be measured according to that standard.

[0030] Preferred characteristics of glaze layer The sanitary ceramic of the present invention has a glaze layer composed of a crystalline phase and an amorphous phase (non-crystalline phase). According to a preferred embodiment of the present invention, the amorphous phase accounts for more than 70 wt% of the glaze layer and less than 90 wt% of the glaze layer.

[0031] Furthermore, according to one embodiment of the invention, the crystalline phase preferably comprises diopside (CaMgSi2O6) or augite ((Ca,Mg,Fe)2Si2O6). By including these, the matte surface can achieve a warm and stable texture. According to a preferred embodiment of the invention, the diopside or augite crystalline phase preferably constitutes 70% or more of the crystalline phase. Furthermore, in a second embodiment of the invention, the crystalline phase comprises cristobalite. This further enhances the warm and stable texture of the matte surface.

[0032] According to one embodiment of the invention, the crystalline phase comprises 0.5 wt% to 5 wt% zircon, preferably with a zircon grain size of about 0.3 to 0.8 μm.

[0033] In this invention, the contents of the crystalline and amorphous phases, the contents of diopside and common pyroxene, and the contents and particle size of zircon can be calculated, for example, from the SEM image of the surface of the enamel layer using image processing software.

[0034] Glaze As long as the aforementioned surface properties can be achieved, the glaze used to generate the glaze layer in this invention is not particularly limited, but the raw materials for the glaze are typically a mixture of natural mineral particles such as silica sand, feldspar, and limestone. Furthermore, pigments may be, for example, cobalt compounds or iron compounds, and opacifiers may be, for example, zirconium silicate or tin oxide. Amorphous glazes refer to glazes in which the glaze raw materials, consisting of a mixture of natural mineral particles as described above, are melted at high temperatures and then rapidly cooled to vitrify; for example, frit glazes are preferably used.

[0035] According to a preferred embodiment of the present invention, the preferred glaze composition is, for example: Feldspar content: 15wt%–30wt%. Silica sand content is 25wt%–45wt%. Dolomite content: 0–10 wt%. Calcium carbonate is 10wt%–20wt%. Alumina content is 4 wt% to 20 wt%. Zinc oxide content is below 10 wt%. In the first form, zircon is less than 10 wt%, and in the second form, black pigment is less than 10 wt%. Talc content is 11 wt% to 15 wt%. The pigment content is less than 15 wt%.

[0036] Examples of black pigments include V2O5, Cr2O3, MnO, Fe2O3, Co2O3, and NiO.

[0037] The preferred composition of the glaze layer in the sanitary ceramic of the present invention, converted into oxides, is as follows: SiO2 content is 60-67 wt%. Al2O3 content was 6–15 wt%. The CaO content is 11 wt% or less (more preferably 6 to 11 wt%). MgO content is 3-9 wt%. The K2O content is less than 2 wt% (more preferably 0.5 to 2 wt%). Na₂O content is 0.5–3 wt%. The ZnO content is 3 wt% or more (more preferably 3 to 10 wt%).

[0038] In the first embodiment of the invention, the Mg / Ca ratio is preferably 0.45 to 0.50 or less, more preferably 0.45 to 0.48. More preferably, MgO is 4 wt%. Using such amounts of Mg and Ca facilitates the formation of diopside crystals.

[0039] In the second aspect of the invention, the Mg / Ca ratio is preferably 0.3 to 0.4 or less, more preferably 0.31 to 0.35. More preferably, the MgO content is 4 wt%. Using such amounts of Mg and Ca facilitates the formation of diopside crystals.

[0040] Pottery blanks The ceramic blanks for the sanitary pottery of the present invention are not particularly limited and can be ordinary sanitary pottery blanks. In addition, a glaze layer as an intermediate layer may be provided under the outermost glaze layer having the above-mentioned surface characteristics.

[0041] Manufacturing method The sanitary pottery of the present invention is preferably manufactured by the following method: First, a sanitary pottery blank slurry made from raw materials such as silica sand, feldspar, and clay is formed into a suitable shape using an absorbent mold and casting. Then, a glaze raw material slurry is applied to the dried surface of the formed body using a conventional method such as spraying, dipping, spinning, or rolling. The formed body, having formed the precursor layer of the obtained surface glaze layer, is allowed to stand until the surface glaze layer is fully dried. After drying, the surface is cut to homogenize and smooth it before firing. Preferably, the firing temperature is between 1000°C and 1300°C, at which the pottery blank is sintered and the glaze softens.

[0042] The third preferred embodiment of the present invention Basic components Figure 12 The diagram shows a cross-sectional schematic of an example of a sanitary ceramic vessel of the third aspect of the present invention, namely a flushing toilet. The flushing toilet in the diagram has a glaze layer on the ceramic blank. The exterior of the toilet has a first glaze surface, which serves as the surface of the first glaze layer, and a second glaze surface, which serves as the surface of the second glaze layer, on the waste-receiving surface 2 of the basin, which is likely to come into contact with waste. The surface indicated by dashed line 11 in the diagram is the first glaze surface, and the surface indicated by dashed line 12 on the waste-receiving surface 2 is the second glaze surface.

[0043] More specifically, the present invention Figure 12 The toilet bowl has a first glaze layer formed on its entire outer surface, and a second glaze layer is formed on a portion of its surface, namely the waste-receiving surface 2, through overlapping application. As a result, as... Figure 12 As shown, a first glaze surface 11 is formed on the area that becomes the appearance of the toilet bowl. In addition, a first glaze layer is first provided on the soil receiving surface 2, and a second glaze layer is provided on it to form a second glaze surface, which is an overlapping coating.

[0044] In this specification, a first glaze layer having specified properties provides a so-called matte surface as the first glaze surface; furthermore, in this specification, a second glaze layer having specified properties provides a so-called anti-fouling surface as the second glaze surface. Therefore, Figure 12 The toilet bowl has a matte surface 11 in the area that forms its appearance. A first glaze layer is first applied to the waste-receiving surface 2, and a second glaze layer is then applied thereon. As a result, a stain-resistant surface is formed, which serves as the surface of the second glaze. That is, in... Figure 12 In the diagram, the dashed line 12 representing the surface of the second glaze layer refers to the surface of the layer on which the second glaze layer is formed by overlapping the first glaze layer, which is a stain-resistant surface.

[0045] In this invention, for example inside the basin, the two surfaces of the first glaze layer and the second glaze layer switch to form a boundary. Figure 13 This is a magnified view of the boundary. For example... Figure 13 As shown, in this invention, a first glaze layer 11 is provided on the ceramic blank 10, and a second glaze layer 12 is provided on it, with the transition between the two forming a boundary 14.

[0046] Furthermore, the surfaces of the first and second glaze layers of the sanitary pottery of the third aspect of the present invention each possess the following characteristics. That is, The surface roughness (Ra) of the first glaze surface is greater than 1 μm. The surface roughness (Ra) of the second glaze is less than 1 μm, preferably less than 0.1 μm, and more preferably less than 0.07 μm. The 60° gloss of the second glaze surface is higher than that of the first glaze surface. The color difference ΔE between the surface of the first glaze and the surface of the second glaze is 17 or less, preferably ΔE is 10 or less. The L value of the second glaze surface is lower than that of the first glaze surface.

[0047] In the sanitary ceramics of the present invention that satisfy the above description, the transition between the first glaze layer and the second glaze layer, i.e., the boundary, is not obvious, and will not give the observer a strong sense of disharmony. By forming such a boundary with less disharmony, the following advantages can be obtained: areas requiring stain resistance can have the appropriate properties, without compromising the overall appearance, texture, and impression of the sanitary ceramics.

[0048] The surface of the matte glaze layer is textured with raised or recessed areas, thereby achieving a matte, non-glossy texture. On the other hand, a glaze layer providing stain resistance or gloss, by smoothing its surface, can achieve a surface where dirt is less likely to adhere and is easily removed, or a glossy surface. If a stain-resistant glaze layer is applied over a matte glaze layer, the surface of the stain-resistant glaze layer will be affected by the raised or recessed areas of the underlying matte surface; therefore, it is preferable to make the stain-resistant glaze layer thicker. Here, simply increasing the thickness of the stain-resistant glaze layer will make the boundary line between the two surfaces more pronounced, and the difference in appearance and the sense of disharmony between the two surfaces will increase, which also depends on the observer's perception. However, in this invention, by satisfying the aforementioned necessary conditions, particularly by reducing the color difference between the two surfaces, and by specifying the relative brightness of the surface of the lower second glaze layer (matte glaze layer) to the surface brightness of the upper first glaze layer (stain-resistant glaze layer), the sense of disharmony for the observer can be reduced.

[0049] According to a preferred embodiment of the third aspect of the present invention, the surface of the first glaze has a gloss level of 5 or less for a 20-degree gloss, 20 or less for a 60-degree gloss, and 30 or less for an 85-degree gloss; the surface of the second glaze has a gloss level of 60 or less for a 20-degree gloss, 90 or less for a 60-degree gloss, and 98 or less for an 85-degree gloss. In this embodiment, the sense of disharmony at the boundaries can be further suppressed.

[0050] According to one embodiment of the third aspect of the invention, the thickness difference between the first enamel layer and the second enamel layer is 0.2 mm or less. Furthermore, according to a further preferred embodiment, the thickness of the first enamel layer is greater than the thickness of the second enamel layer. According to other preferred embodiments, the thickness of the first enamel layer is 0.4 to 1.0 mm, and the thickness of the second enamel layer is 0.2 to 0.8 mm. By satisfying the above conditions, the disharmony at the boundary between the first and second enamel layers can be further suppressed.

[0051] According to another embodiment of the invention, the boundary between the first glaze layer and the second glaze layer is located on the longitudinal surface of the sanitary pottery. For example, the boundary 13 is set at... Figure 12On the inner longitudinal surface of the inner edge portion 3. This further suppresses the sense of disharmony at the boundary between the first enamel layer and the second enamel layer.

[0052] The glaze of the first glaze layer In this invention, the first glaze layer, i.e., the matte glaze layer, can be exemplified by the glazes described in Japanese Patent Application Publication No. 6-211541, Japanese Patent Application Publication No. 2-229736, and Japanese Patent Application Publication No. 2012-046364.

[0053] Furthermore, the preferred matte enamel coating in this invention is as follows. The sanitary pottery of the present invention has a basic structure comprising a pottery blank and a glaze layer on its surface. Furthermore, as its surface characteristics, the glaze layer of the sanitary pottery of the present invention satisfies the following necessary conditions: a 20° gloss level of 5 or less, a 60° gloss level of 20 or less, an 85° gloss level of 30 or less, and a surface roughness Ra of 1.0 μm or more. According to a preferred embodiment of the present invention, the 20° gloss level is 3.5 or less, the 60° gloss level is 18 or less, and the 85° gloss level is 29 or less.

[0054] The glaze layer that meets the above-mentioned necessary conditions has a matte surface, and is a matte surface with a warm and calm texture, which can suppress the so-called "glare" observed on existing matte surfaces. Although the observer's perception of "warmth" and "calmness" is not easy to quantify, according to the present invention, such a matte surface can be achieved by a combination of the gloss, color and surface roughness of the glaze layer, thus providing a novel matte surface.

[0055] The surface roughness Ra of the matte glaze layer in the sanitary ceramic of the present invention is 1.0 μm or more, preferably in the range of 1.1 μm or more to 1.9 μm or less. The surface roughness Ra is the arithmetic mean roughness, which can be defined in JIS Japanese Industrial Standard B 0601:2001 and can be measured according to that standard.

[0056] The sanitary ceramic of the present invention has a matte glaze layer composed of a crystalline phase and an amorphous phase (non-crystalline phase). According to a preferred embodiment of the present invention, the amorphous phase accounts for more than 70 wt% and less than 90 wt% of the glaze layer.

[0057] Furthermore, according to one embodiment of the invention, the crystalline phase preferably comprises diopside (CaMgSi2O6) or Augite ((Ca,Mg,Fe)2Si2O6). By including these, a warm and stable texture can be better achieved on the matte surface. According to a preferred embodiment of the invention, the crystalline phase preferably comprises 70% or more of diopside or Augite. Furthermore, according to another preferred embodiment of the invention, the crystalline phase preferably comprises diopside (CaMgSi2O6) or Augite ((Ca,Mg,Fe)2Si2O6). By including these, a warm and stable texture on the matte surface can be better achieved. According to a preferred embodiment of the invention, the crystalline phase preferably comprises 70% or more of diopside or Augite. And, according to another preferred embodiment of the invention, the crystalline phase comprises cristobalite. Thus, a warm and stable texture on the matte surface can be better achieved.

[0058] According to one embodiment of the invention, the crystalline phase comprises 0.5 wt% to 5 wt% zircon, preferably with a zircon grain size of about 0.3 to 0.8 μm.

[0059] In this invention, the content of the crystalline phase and the amorphous phase, the content of diopside and common pyroxene, and the content and particle size of zircon can be calculated, for example, from the SEM image of the surface of the enamel layer using image processing software.

[0060] As long as the aforementioned surface properties can be achieved, the glaze used to generate the glaze layer in this invention is not particularly limited, but the raw materials for the glaze are typically a mixture of natural mineral particles such as silica sand, feldspar, and limestone. Furthermore, pigments may be, for example, cobalt compounds or iron compounds, and opacifiers may be, for example, zirconium silicate or tin oxide. Amorphous glazes refer to glazes that are vitrified by rapidly cooling glaze raw materials composed of a mixture of natural mineral particles as described above after melting at high temperatures; for example, frit glazes are preferably used.

[0061] According to a preferred embodiment of the invention, the matte enamel composition is, for example, Feldspar content: 15wt%–30wt%. Silica sand content is 25wt%–45wt%. Dolomite content: 0–10 wt%. Calcium carbonate is 10wt%–20wt%. Alumina content is 4 wt% to 20 wt%. Zinc oxide content is below 10 wt%. Zircon content is below 10 wt%. Talc content is 11 wt% to 15 wt%. The pigment content is less than 15 wt%.

[0062] The preferred composition of the matte glaze layer in the sanitary ceramics of the present invention, converted into oxides, is as follows: SiO2 content is 60-67 wt%. Al2O3 content was 6–15 wt%. The CaO content is 11 wt% or less (more preferably 6 to 11 wt%). MgO content is 3-9 wt%. The K2O content is less than 2 wt% (more preferably 0.5 to 2 wt%). Na₂O content is 0.5–3 wt%. The ZnO content is 3 wt% or more (more preferably 3 to 10 wt%).

[0063] According to a preferred embodiment of the invention, the Mg / Ca ratio is 0.45 to 0.50 or less, more preferably 0.45 to 0.48. More preferably, MgO is 4 wt%. With such amounts of Mg and Ca, diopside crystals are readily formed.

[0064] The glaze of the second glaze layer In this invention, the second glaze layer, i.e. the anti-fouling glaze layer, can be exemplified by the glaze layers described in International Patent No. WO99 / 061392 and Japanese Patent Application Publication No. 2002-206269.

[0065] As the second glaze layer, it is preferable to use a mixture of natural mineral particles such as silica sand, feldspar, and limestone, as well as amorphous raw materials, as glaze raw materials. Here, amorphous raw materials refer to raw materials that are melted and vitrified at high temperatures by mixing the glaze raw materials composed of the mixture of natural mineral particles such as silica sand, feldspar, and limestone; for example, sintered raw materials are preferred. Furthermore, it is preferable to pre-micronize the silica sand or the like containing quartz particles used here. This prevents quartz particles from remaining on the surface of the glaze after firing. To produce a stain-resistant glaze, it is preferable to mix the above-mentioned mixture of natural mineral particles and amorphous raw materials such that the proportion of amorphous glaze relative to the total of the two is 50 to 99% by weight, more preferably 60 to 90%, and mix them using a ball mill or the like, and then pulverize them as needed.

[0066] The glaze composition of the second glaze layer is preferably as follows. SiO2 content is 52-76 wt%. Al2O3 content was 6–14 wt%. MgO content is 0.5–4 wt%. CaO content is 6–17 wt%. ZnO content is 3–11 wt%. K2O content is 1-5 wt%. The Na2O content is 0.5–2.5 wt%.

[0067] Furthermore, according to a preferred embodiment of the present invention, the surface of the second enamel layer is a smooth surface with a height of Ra of 0.1 μm or less, more preferably 0.07 μm or less, as defined in JIS Japanese Industrial Standard B 0601:2001. Example

[0068] The present invention will be further illustrated by the following embodiments, but the present invention is not limited to these embodiments.

[0069] Examples A1 to A3 Two kg of natural mineral particles (compositions listed in Table 1 and particle sizes in Table 2), one kg of water, and four kg of pebbles were added to a 6-liter ceramic jar. The mixture was then pulverized using a ball mill for approximately 24 hours to obtain a glaze slurry. Next, a 70×70 mm plate-shaped test piece was prepared using a sanitary pottery blank slurry made from silica sand, feldspar, and clay. The glaze was then applied to this plate-shaped test piece using a wet spraying method to a thickness of at least 1.0 mm. After allowing it to dry completely, the dried surface was cut to homogenize and smooth it before firing at 1100–1200°C. This yielded the samples for Examples A1 to A3.

[0070] In addition, similar to Examples A1 to A3, but by adjusting the composition of feldspar (15wt% to 30wt%), silica sand (25wt% to 45wt%), dolomite (0wt% to 10wt%), calcium carbonate (10wt% to 20wt%), alumina (4wt% to 20wt%), zinc oxide (less than 10wt%), zircon (less than 10wt%), talc (11wt% to 15wt%), and pigment (less than 15wt%), samples of Examples A4 to A8 and Comparative Example A4 with the composition described in Table 3 below were prepared. (Table 1) (Table 2)

[0071] Comparative Examples A1 to A3 The following three commercially available products with a matte glaze layer were obtained as Comparative Examples 1 to 3. Comparative Example A1: Washbasins manufactured by Company A Comparative Example A2: Washbasin manufactured by Company B Comparative Example A3: Washbasin manufactured by Company C

[0072] Composition of glaze layer The composition of the enamel layers in Examples A1 to A8 and Comparative Examples A1 to A4 was analyzed. Specifically, the analysis was performed using a fluorescence X-ray analysis apparatus (Rigaku Corporation: ZXS Primus IV), with a voltage of 30–50 kV, a current of 60–100 mA, and a measurement range of 20 mmΦ. The results are shown in the table below. (Table 3)

[0073] Gloss measurement Based on JIS Japanese Industrial Standard Z8741, the gloss of the glaze layers of Examples A1 to A8 and Comparative Examples A1 to A4 was measured using a gloss meter (KONICA MINOLTA: Multi-Gloss 268). The measurement range was 10mm × 10mm at a measurement angle of 20°, 9mm × 15mm as an ellipse at a measurement angle of 60°, and 5mm × 38mm as an ellipse at a measurement angle of 85°. The results are shown in Table 4 below.

[0074] Determination of surface L* value The L* values ​​of the glaze layers of Examples A1 to A8 and Comparative Examples A1 to A4 were measured using a spectrophotometer (KONICA MINOLTA, CM-3700A). The measurement diameter was 25.4 mm, the positive reflection light treatment was SCE, and the light source was a D65 light source. The results are shown in Table 4 below.

[0075] Determination of surface roughness Ra The Ra values ​​of the enamel layers of Examples A1 to A8 and Comparative Examples A1 to A4 were measured using a laser microscope (Lasertec: OPTELICS HYBRID+). The cutoff values ​​were λc: 0.8 mm and λs: 0.0025 mm. The results are shown in Table 4 below.

[0076] (Table 4)

[0077] SEM Image Analysis: Crystalline and Amorphous Phases SEM images of the surfaces of the glaze layers in Examples A1 to A3 and Comparative Examples A1 to A3 were captured. These images are as follows: Figures 1-6As shown. Using image analysis software, the proportions of (1) crystalline and amorphous phases, and (2) the presence and amount of diopside or common pyroxene in the crystalline phase were calculated from these SEM images. The calculation was performed by taking three SEM images of each sample, each with a field of view of 60 μm × 80 μm, then binarizing the particles, and calculating from the area ratio.

[0078] The results are shown in the table below. (Table 5)

[0079] Particle size determination For each sample, SEM images of the glaze layer in Examples A1 to A3 were taken in three fields of view, each measuring 60 μm × 80 μm. The long axes of the crystalline particles other than zircon were counted at a 5 μm scale. The results are shown in the table below. (Table 6)

[0080] Evaluation of matte finish Ten technical personnel related to the development of sanitary ceramics served as reviewers. The surfaces of the glaze layers of Examples A1 to A8 and Comparative Examples A1 to A4 were visually observed. The corresponding performance of the surface matte was evaluated against the following criteria 1 and 2. The maximum and minimum values ​​were then removed and the average of the obtained scores was calculated.

[0081] <Benchmark 1> 5 points for a finely textured matte surface. 4 points: a matte surface with a slight glare, but not a major concern. 3 points: A finely textured matte surface, but one that may cause glare. 2 points for a glaringly matte surface. 1. A matte surface with a glossy, rough feel (rough surface, seemingly rough).

[0082] <Benchmark 2> 5 points indicates a sense of composure A score of 4 indicates overall composure. 3 points indicates no obvious tendency A score of 2 indicates a lack of composure overall. 1 point for being unstable

[0083] The results are shown in the table below. (Table 7)

[0084] Examples B1 to B3 2 kg of natural mineral particles (compositions listed in Table 1 and particle sizes in Table 2), 1 kg of water, and 4 kg of pebbles were added to a 6-liter ceramic jar. The jar was then pulverized using a ball mill for approximately 24 hours to obtain a glaze slurry. Next, a 70×70 mm plate-shaped test piece was prepared using a sanitary pottery blank slurry made from silica sand, feldspar, and clay. The glaze was then applied to the plate-shaped test piece using a wet spraying method to a thickness of at least 1.0 mm. After standing until fully dry, the plate was ground to smooth the dried surface. Finally, it was fired at 1100–1200 °C to obtain the samples of Examples B1–B3.

[0085] In addition, similar to Example B1, but by adjusting the composition of feldspar (15wt%–30wt%), silica sand (25wt%–45wt%), dolomite (0–10wt%), calcium carbonate (10wt%–20wt%), alumina (4wt%–20wt%), zinc oxide (less than 10wt%), zircon (less than 10wt%), talc (11wt%–15wt%), and pigment (less than 15wt%), a sample of Comparative Example B6 with the composition described in Table 3 below was prepared. (Table 8) (Table 9)

[0086] Comparative Examples B1 to B5 Five commercially available products with a matte black glaze layer were obtained as Comparative Examples 1 to 5. Comparative Example B1: Washbasins manufactured by Company A Comparative Example B2: Washbasin manufactured by Company B Comparative Example B3: Washbasin manufactured by Company C Comparative Example B4: Washbasin manufactured by Company D Comparative Example B5: E Company's flush toilet

[0087] Composition of glaze layer The composition of the enamel layers in Examples B1, B2, and Comparative Examples B1 to B6 was analyzed using the same analytical methods as in Example A. The results are shown in the table below. (Table 10)

[0088] Gloss measurement Similar to Example A, the gloss of the surface of the glaze layers in Examples B1 and B2, and Comparative Examples B1 to B6, was measured. The results are shown in Table 4 below.

[0089] Determination of surface L* value Similar to Example A, the L* values ​​of the surface of the glaze layers in Examples B1 and B2, and Comparative Examples B1 to B6, were measured. The results are shown in Table 4 below.

[0090] Determination of surface roughness Ra Similar to Example A, the surface roughness Ra values ​​of the glaze layers in Examples B1 and B2, and Comparative Examples B1 to B6, were measured. The results are shown in Table 4 below.

[0091] (Table 11)

[0092] SEM Image Analysis: Crystalline and Amorphous Phases SEM images of the surface of the glaze layer in Example B1 and Comparative Examples B1 to B4 were captured. These images are as follows: Figures 7-11 As shown. Using image analysis software, the proportions of (1) crystalline and amorphous phases, and (2) the presence and amount of diopside or common pyroxene in the crystalline phase were calculated from these SEM images. The calculation was performed by taking three SEM images of each sample, each with a field of view of 60 μm × 80 μm, then binarizing the particles, and calculating from the area ratio.

[0093] The results are shown in the table below. (Table 12)

[0094] Particle size determination For each sample, three SEM images of the glaze layer from Example B1 were taken, each with a field of view of 60 μm × 80 μm. The long axes of the crystalline particles other than zircon were counted at a 5 μm scale. The results are shown in the table below. (Table 13)

[0095] Evaluation of matte finish Ten technical personnel involved in the development of sanitary ceramics served as reviewers. The surfaces of the glaze layers of Examples B1 to B8 and Comparative Examples B1 to B4 were visually observed and evaluated using the same criteria as in Example A, based on the corresponding performance of the matte finish of the surfaces.

[0096] The results are shown in the table below. (Table 14)

[0097] Example C Glaze preparation and glazing methods (1) Preparation of pottery blank test pieces Next, using a slurry of sanitary pottery blanks made from silica sand, feldspar, clay, and other raw materials, 70×70mm plate-shaped test pieces were made. (2) Glaze used for the first glaze layer (matte glaze) Add 2 kg of natural mineral particles (as shown in Table 1 and Table 2) with 1 kg of water and 4 kg of pebbles to a 6-liter ceramic jar, and pulverize using a ball mill for about 24 hours to obtain a glaze slurry. (Table 15) (Table 16)

[0098] (3) Glaze used for the second glaze layer (anti-fouling glaze) The raw materials and amorphous glaze were adjusted such that the amorphous glaze accounted for 50-99% by weight of the total of the two. 2 kg of the adjusted glaze raw materials, 1 kg of water, and 4 kg of pebbles were added to a 6-liter ceramic jar. The glaze slurry was then pulverized using a jar mill, with particle size analysis using a laser diffraction particle size analyzer showing that 67% of the slurry was below 10 μm and the average particle size (D50) of 50% was 6.0 μm. This yielded a stain-resistant glaze slurry. Here, amorphous raw materials refer to glaze raw materials composed of a mixture of natural mineral particles such as silica sand, feldspar, and limestone, which are melted and vitrified at high temperatures.

[0099] Raw material composition SiO2 content is 52-76 wt%. Al2O3 content was 6–14 wt%. MgO content is 0.5–4 wt%. CaO content is 6–17 wt%. ZnO content: 3–11 wt% K2O content: 1–5 wt% The Na2O content is 0.5–2.5 wt%.

[0100] Examples C1 to C4 On the plate-shaped test piece obtained by (1) above, a glaze for the first glaze layer obtained by (2) above is applied by wet spraying to a thickness of 1.0 mm or more. The plate is allowed to dry completely, and the dried surface is then cut to homogenize and smooth it. Subsequently, only half of the test piece is coated with an anti-fouling glaze obtained by wet spraying of the glaze for the second glaze layer obtained by (3) above to a thickness of 0.3 to 0.4 mm. The samples of Examples C1 to C4 are then obtained by firing at 1100 to 1200 °C.

[0101] The Lab value, color difference, surface roughness, and gloss of the samples obtained in Examples C1 to C4 were measured. The results are shown in the table below. (Table 17)

[0102] Comparative Example C1 Before applying the glaze (anti-fouling glaze) for the second glaze layer, a glossy glaze with the following composition was applied to a thickness of 0.15 mm or more using a wet spraying method. Subsequently, the glaze (anti-fouling glaze) for the second glaze layer was applied. Otherwise, the same procedure as in Example C1 was followed to obtain the sample. This was used as Comparative Example 1.

[0103] Composition of raw materials for glossy glaze (Table 18)

[0104] The Lab value, color difference, surface roughness, and gloss of the obtained comparative example C1 sample were measured. The results are shown in the table below. (Table 19)

[0105] evaluate For Example C1 and Comparative Example C1, their appearance was evaluated under the following conditions: The samples were placed under the illumination of a typical toilet space (100-150 lux) using two standard colorimetric illumination sources, namely the D65 light source and the A light source. Fifteen sanitary ware technicians visually observed the samples and then asked the following questions, inquiring about their reasoning. Question 1: Which combination do you prefer? Question 2: Which combination does not feel discordant?

[0106] The number of respondents and their reasons are shown in the table below. (Table 20)

[0107] Although there were differing opinions on preferences in question 1 (preference for combinations), the implementation examples clearly received higher ratings for question 2 (whether there was a sense of disharmony).

Claims

1. A sanitary pottery, comprising a pottery blank and a glaze layer on its surface, characterized in that, The surface of the glaze layer has the following characteristics. (1) 20° gloss level is below 5, 60° gloss level is below 20, and 85° gloss level is below 30. (2) The surface roughness Ra is 1.0 μm or more.

2. The sanitary pottery according to claim 1, characterized in that, The glaze layer contains 70wt% to 90wt% of amorphous, i.e., non-crystalline phase.

3. The sanitary pottery according to claim 1 or 2, characterized in that, The glaze layer contains a crystalline phase, which includes diopside or common pyroxene.

4. The sanitary pottery according to claim 3, characterized in that, The diopside or common pyroxene of the crystalline phase constitutes more than 70% of the crystalline phase.

5. The sanitary pottery according to claim 3, characterized in that, The crystalline phase contains 0.5 wt% to 5 wt% zircon, i.e., an opacifier.

6. The sanitary pottery according to claim 3, characterized in that, The crystalline phase comprises cristobalite.

7. The sanitary pottery according to claim 1, characterized in that, The glaze layer contains more than 3 wt% ZnO.

8. The sanitary pottery according to claim 7, characterized in that, The glaze layer contains less than 11 wt% CaO and less than 2 wt% K2O.

9. The sanitary pottery according to any one of claims 1 to 8, characterized in that, The glaze layer has a first glaze surface and a second glaze surface. A second glaze layer, which is used to impart a second glaze surface, is formed on a portion of the first glaze layer that imparts a first glaze surface. Both the first and second glaze surfaces are formed within the glaze layer. The surface roughness Ra of the first glaze is greater than 1 μm. The surface roughness Ra of the second glaze is less than 1 μm. The 60° gloss of one side of the second glaze surface is higher than that of the first glaze surface. The color difference ΔE between the surface of the first glaze and the surface of the second glaze is less than 17. The L value of the second glaze surface is lower than that of the first glaze surface.

10. The sanitary pottery according to claim 9, characterized in that, The first glaze surface is a matte glaze layer surface, and the second glaze surface is a stain-resistant glaze layer surface.

11. The sanitary pottery according to claim 9, characterized in that, The thickness of the first glaze layer is greater than the thickness of the second glaze layer.

Images