Glass formers and their uses

Abstract

To provide a technique that can suitably improve alkali resistance of a decorative film formed on a glaze layer, the glaze layer provided on a substrate.SOLUTION: A glass forming agent disclosed herein forms a glass film for protecting a decorative film formed on a substrate. The glass forming agent comprises glass matrix elements. The glass matrix elements comprise at least Si and a rare earth element. When the total mol of the glass matrix elements is 100 mol%, the content of the rare earth element is 1 mol%-70 mol%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to glass formers and their uses. [Background technology]

[0002] Decorative films containing precious metal components are sometimes formed on the surfaces of articles such as ceramics, glassware, enamelware, etc. to impart an elegant or luxurious impression. These types of articles are typically formed by applying a decorative composition containing predetermined components onto a substrate, followed by a firing treatment.

[0003] Incidentally, some of these types of articles (e.g., tableware) are expected to be immersed in alkaline detergents. In this case, there is a risk that the decorative film formed on the substrate may be damaged by the alkaline detergent. For this reason, decorative compositions capable of forming decorative films with excellent alkali resistance have been proposed in recent years. For example, Patent Document 1 discloses a liquid gold for ceramic overglaze decoration that contains elements such as nickel to improve alkali resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3784973 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to further enhance water resistance, a glaze layer is sometimes applied to the substrate. The inventors have found that such a glaze layer is easily damaged by alkaline solutions such as alkaline detergents, which can easily peel off a decorative film formed on the glaze layer. Therefore, there is a need for a technology that can effectively prevent peeling of a decorative film caused by alkaline solutions, even when a glaze layer is applied to the substrate.

[0006] The present invention has been made in consideration of the above circumstances, and its main purpose is to provide a technology that can suitably improve the alkali resistance of a decorative film formed on a glaze layer of a substrate to which a glaze layer has been applied. [Means for solving the problem]

[0007] To achieve this object, the present invention provides an article comprising a substrate, a glaze layer formed on the substrate, a decorative film formed on the glaze layer, and a glass film formed from any of the glass formers disclosed herein, the glass film being present between the glaze layer and the decorative film and / or on the decorative film. In such an article, the rare earth element is present in the largest amount in the glass film among the substrate, the glaze layer, the decorative film, and the glass film.

[0008] The inventors discovered that an article having a structure in which a glass film formed from the glass former disclosed herein is provided between a glaze layer and a decorative film and / or on top of the decorative film can effectively prevent peeling of the decorative film, even when exposed to alkaline solutions, because the glass film protects the glaze layer, thereby effectively preventing peeling of the decorative film. Furthermore, while not intended to be particularly limiting, the glass film contains rare earth elements, which have high oxygen affinity and can exist doped in the glass matrix, which may tighten the glass network structure. Furthermore, rare earth oxides in the glass matrix may remain and form a film even after other components are eluted by exposure to alkaline solutions. These factors effectively prevent the penetration of alkaline components into the glass matrix. Therefore, the glass film protects the glaze layer from alkaline components, thereby effectively improving the alkali resistance of the decorative film.

[0009] In a preferred embodiment of the article disclosed herein, the glass film has an average thickness of 20 nm to 500 nm. When the article includes a glass film with such a small average thickness, the color and texture of the decorative film can be suitably exhibited.

[0010] In the article disclosed herein, for example, at least the surface of the substrate may be made of ceramic, and the article disclosed herein may constitute, for example, tableware.

[0011] In another aspect, the present invention provides a glass former for forming a glass film for protecting a decorative film formed on a glaze layer of a substrate provided with the glaze layer, the glass former including glass matrix elements including at least Si and a rare earth element, and a content of the rare earth element being 1 mol % to 70 mol % when the total number of moles of the glass matrix elements is taken as 100 mol %.

[0012] The present inventors have found that a glass film having excellent alkali resistance can be formed by using a glass former containing a predetermined amount of rare earth elements as glass matrix elements.

[0013] In a preferred embodiment of the glass former disclosed herein, the rare earth element is at least one selected from the group consisting of Sm, Y, Pr, and Nd. A glass former containing an element such as the rare earth element described above can more suitably improve the alkali resistance of a decorative film formed on a glaze layer of a substrate provided with the glaze layer.

[0014] In a preferred embodiment of the glass former disclosed herein, the content of the rare earth element is 3 mol % to 30 mol % when the total number of moles of the glass matrix elements is 100 mol %. A glass former with a rare earth element content within this range can more suitably improve the alkali resistance of a decorative film formed on a glaze layer of a substrate provided with the glaze layer.

[0015] In a preferred embodiment of the glass former disclosed herein, Bi is further included as a glass matrix element. The glass former further including Bi as a glass matrix element can more suitably improve the alkali resistance of a decorative film formed on a glaze layer of a substrate provided with the glaze layer.

[0016] The glass former disclosed herein can be suitably applied to the formation of a glass film for protecting a decorative film formed on a glaze layer of a substrate, for example, at least the surface of which is made of ceramic and to which a glaze layer is applied. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram schematically showing a cross-sectional structure of an article according to a first embodiment. [Figure 2] FIG. 4 is a diagram schematically showing a cross-sectional structure of an article according to a second embodiment. [Figure 3]FIG. 10 is a diagram schematically showing the cross-sectional structure of an article according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the technology disclosed herein are described below. Matters necessary for implementation other than those specifically mentioned in this specification (e.g., detailed preparation methods for glass formers, decorative compositions, and glazes, and manufacturing procedures for articles, etc.) can be understood based on the technical content taught by this specification and the general technical common sense of a person skilled in the art. The technology disclosed herein can be implemented based on the content disclosed in this specification and the general technical common sense of a person skilled in the art. The expression "A to B" used in this specification to indicate a range means greater than A and less than B. Therefore, it includes cases where the range is greater than A and less than B.

[0019] <Glass former> The glass former disclosed herein is used to form a glass film for protecting a decorative film formed on a glaze layer of a substrate to which the glaze layer is applied. The glass former disclosed herein also contains glass matrix elements, which contain at least Si (silicon) and rare earth elements. When the total number of moles of the glass matrix elements is taken as 100 mol%, the content of the rare earth elements (hereinafter simply referred to as "the content of rare earth elements in the glass former") is 1 mol% to 70 mol%. Each of the constituent components will be described below.

[0020] (1) Glass matrix elements In this specification and claims, the term "glass matrix elements" refers to metal elements and metalloid elements that can form a glass matrix when a glass film (typically, an oxide glass film) is formed. Examples of such glass matrix forming elements include Al, Ti, Zr, Si, Bi, Sm, Y, La, Ce, Pr, Nd, Sm, Dy, Sn, Zn, Be, Mg, Ca, Sr, Ba, Li, Na, K, Rb, B, V, Fe, Cu, P, Sc, Pm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu, Ni, In, Co, and Cr. The form of the glass matrix elements in the glass former is not particularly limited and can take various forms, such as metal resinates, complexes, polymers, and fine particles (glass frit). As described above, the glass former disclosed herein contains at least Si and a rare earth element as glass matrix elements.

[0021] Si is an element that becomes silicon oxide (SiO2) after firing and can constitute the skeleton of the glass matrix. The Si content (mol %) (hereinafter simply referred to as the "Si content in the glass former") when the total number of moles of glass matrix elements in the glass former is taken as 100 mol % is not particularly limited as long as the effects of the technology disclosed herein are exhibited. The Si content in the glass former may be, for example, 20 mol % or more, 30 mol % or more, 40 mol % or more, or 50 mol % or more. The Si content in the glass former is generally 99 mol % or less, and may be, for example, 95 mol % or less, 90 mol % or less, or 85 mol % or less.

[0022] The rare earth elements can be selected without limitation from scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). The rare earth elements may be used singly or in combination. These rare earth elements have high oxygen affinity, so for example, when doped into a glass matrix, they can tighten the glass network structure. Furthermore, rare earth oxides remain and form a coating even after other components are dissolved by exposure to alkaline solutions. These properties effectively prevent alkaline components from penetrating into the glass matrix. Among the rare earth elements mentioned above, Sm, Y, Pr, and Nd are preferably used because they can suitably improve the alkali resistance of the glass film.

[0023] In the glass former disclosed herein, the content of the rare earth element in the glass former is specified to be 1 mol % or more in order to fully utilize the effect of the rare earth element in improving alkali resistance. Furthermore, the content (mol %) of the rare earth element in the glass former (when two or more types are contained, the total mol %) is preferably 2 mol % or more, more preferably 3 mol % or more, in order to more suitably improve the alkali resistance of the glass film. On the other hand, increasing the content of the rare earth element in the glass film tends to reduce the proportion of Si and other components that form the skeleton of the glass matrix, thereby reducing the mechanical strength of the glass film itself. For this reason, in the glass former disclosed herein, the content of the rare earth element in the glass former is specified to be 70 mol % or less. Furthermore, the content of the rare earth element in the glass former is preferably 65 mol % or less, 60 mol % or less, or 55 mol % or less, more preferably 50 mol % or less, 40 mol % or less, and even more preferably 30 mol % or less. That is, the content of the rare earth element in the glass former can be preferably set to 3 mol % to 30 mol %.

[0024] The glass former disclosed herein preferably further contains Bi (bismuth) as a glass matrix element. Bi is an element that becomes bismuth oxide (Bi2O3) after firing and can constitute part of the framework of the glass matrix. Bi2O3 has the effect of softening glass, which is believed to improve the adhesion of the glass film to other layers (or films). This improved adhesion can effectively prevent peeling of the glass film when exposed to an alkaline solution. The Bi content (mol %) (hereinafter simply referred to as the "Bi content in the glass former"), where the total number of moles of the glass matrix elements in the glass former is taken as 100 mol %, may be, for example, 1 mol % or more, 3 mol % or more, 5 mol % or more, or 7 mol % or more. The upper limit of the Bi content in the glass matrix elements may be, for example, 20 mol % or less, 15 mol % or less, or 11 mol % or less.

[0025] The glass former disclosed herein may contain, for example, elements other than Si, rare earth elements, and Bi (hereinafter also referred to as "optional elements") among the glass matrix elements described above, as long as the effects of the technology disclosed herein can be obtained. The optional elements may be used singly or in combination of two or more. Furthermore, the lower limit of the content (mol %) of the optional elements (hereinafter also simply referred to as the "content of optional elements in the glass former"; when two or more elements are contained, this refers to the total mol %) when the total number of moles of the glass matrix elements in the glass former is taken as 100 mol %) is not particularly limited, and may be 0.1 mol % or more, 0.5 mol % or more, or 1.0 mol % or more. On the other hand, from the viewpoint of preventing a relative decrease in the content of active components (e.g., Si, rare earth elements) that affect the alkali resistance of the glass film, the upper limit of the content of the optional elements in the glass former is preferably 10 mol % or less, more preferably 5 mol % or less.

[0026] (2) Other ingredients The glass matrix elements contained in the glass former disclosed herein have been described above. It is preferable that the glass former disclosed herein contains, in addition to the above-described components, various other components added in consideration of the formability of the glass film, etc. Hereinafter, other components that may be contained in the glass former disclosed herein will be described. However, the other components described below may be any conventionally known components that may be used in glass formers, without particular limitation, as long as they do not significantly impede the effects of the technology disclosed herein. In other words, the components of the glass former disclosed herein other than the above-described essential components may be appropriately changed depending on the application, etc.

[0027] First, as described above, the glass former disclosed herein may contain each of the glass matrix elements in the form of a metal resinate. A metal resinate can refer to an organic compound containing a metal (or a paste, slurry, or ink containing the same). Such an organic compound can include, for example, a metal and a conventionally known resin material that can be used as an organic substance in a metal resinate. Examples of such resin materials include carboxylic acids with a high carbon number (e.g., 8 or more carbon atoms), such as octylic acid (2-ethylhexanoic acid), abietic acid, naphthenic acid, stearic acid, oleic acid, linolenic acid, and neodecanoic acid; sulfonic acids; resin acids contained in rosin; resin sulfide balsams containing essential oil components such as turpentine oil and lavender oil; alkyl mercaptides (alkylthiolates), aryl mercaptides (arylthiolates), mercaptocarboxylic acid esters, and alkoxides. Commercially available metal resinates can be used. In addition, for example, when using Si resinate, one type of Si resinate may be used, or two or more types of Si resinates may be mixed and used, as long as the effects of the technology disclosed herein are exhibited. The same applies to resinates of other elements.

[0028] In addition, in a glass former containing each of the glass matrix elements in the form of a metal resinate, it is preferable to use a solvent (typically an organic solvent) that disperses or dissolves the metal resinate. As such an organic solvent, for example, any of the conventionally known organic solvents used in this type of glass former or resinate paste can be used without particular limitation. Examples of such organic solvents include 1,4-dioxane, 1,8-cineole, 2-pyrrolidone, 2-phenylethanol, N-methyl-2-pyrrolidone, p-tolualdehyde, benzyl benzoate, butyl benzoate, eugenol, caprolactone, geraniol, methyl salicylate, cyclohexanone, cyclohexanol, cyclopentyl methyl ether, citronellal, di(2-chloroethyl)ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, dihydrocarvone, dibromomethane, dimethyl sulfoxide, dimethylformamide, nitrobenzene, pyrrolidone, propylene glycol monophenyl ether, pulegone, benzyl acetate, benzyl alcohol, benzaldehyde, and various oils such as turpentine oil and lavender oil. Commercially available organic solvents can be used. These organic solvents may be used alone or in combination. Furthermore, since metal resinates are commercially available as resinate pastes, for example, such resinate pastes may be used as they are.

[0029] The content of the organic solvent (or the total content when two or more types are contained) is not particularly limited and is preferably adjusted appropriately depending on the means used to apply the glass-forming agent to another layer (or film). For example, when inkjet printing or a spin coater is used, the viscosity of the glass-forming agent needs to be controlled to a relatively low range (e.g., about 10 mPa·s to 500 mPa·s). Therefore, in glass-forming agents for inkjet printing, the weight of the organic solvent is preferably adjusted to a range of 10 wt% to 99 wt% when the total weight of the glass-forming agent is taken as 100 wt%. On the other hand, when brush coating or screen printing is used, it is preferable to form a glass film of sufficient thickness in a single application, so the content of the organic solvent is preferably adjusted to a range of about 0 wt% to 10 wt%, resulting in a glass-forming agent with a viscosity of about 500 mPa·s to 100,000 mPa·s.

[0030] The glass formers disclosed herein may also contain other additional components as long as they do not significantly impair the effects of the technology disclosed herein. Examples of such additional components include organic binders, protective materials, surfactants, thickeners, pH adjusters, preservatives, antifoaming agents, plasticizers, stabilizers, and antioxidants. Commercially available products can be used. The organic binder can be, for example, an organic binder resin such as a cellulose-based resin. The content of the organic binder can be, for example, within the range of 0% to 50% by weight, where the total weight of the glass former is 100% by weight. When using additional components containing metal elements or metalloid elements in the technology disclosed herein, it is necessary to prepare the glass former so that the Si content and rare earth element content are the desired values, taking into account the content of elements derived from the additional components.

[0031] As described above, the form of the glass matrix element contained in the glass-forming agent disclosed herein is not limited to metal resinates and may be, for example, a complex, a polymer, or fine particles. For example, when a complex is used, the type of ligand constituting the complex is not particularly limited, and examples include alkoxide-based ligands, diketone-based ligands, carboxylate-based ligands, and amine-based ligands. Such complexes can be commercially available, for example. When the glass matrix element takes a form other than a metal resinate, it is preferable to appropriately change the solvent and additional components described above depending on the form of the glass matrix element. For example, when the glass matrix element is contained in a form that is insoluble in a solvent, such as fine particles, it is preferable to select a solvent that can appropriately disperse the fine particles and add a dispersant or other additional component.

[0032] <Item composition> Next, one embodiment (first embodiment) of an article having a glass film formed from the glass former disclosed herein will be described with reference to Fig. 1. Note that the following description is not intended to limit the article disclosed herein to the following form.

[0033] FIG. 1 is a schematic diagram illustrating the cross-sectional structure of an article according to a first embodiment. As shown in FIG. 1, the article according to the first embodiment includes a substrate 2, a glaze layer 3 formed on the substrate, a decorative film 5 formed on the glaze layer, and a glass film 4 formed from any of the glass formers disclosed herein and disposed between the glaze layer and the decorative film. In this way, the article 1, which includes the glass film 4 between the glaze layer 3 and the decorative film 5, protects the glaze layer 3 with the alkali-resistant glass film 4, even when exposed to an alkaline solution, thereby effectively preventing peeling of the decorative film 5. Furthermore, this configuration allows the decorative film 5 to be the outermost surface, which is preferable because it is less susceptible to color development due to the glass film 4 coating. Since the glass formers disclosed herein contain rare earth elements, the article 1 is characterized in that the rare earth elements are present in the glass film 4 in the greatest amount among the substrate 2, glaze layer 3, decorative film 5, and glass film 4. Such characteristics can be confirmed by, for example, element mapping or line analysis using FESEM-EDX (field emission scanning electron microscope-energy dispersive X-ray analysis). Each of the components of the product 1 will be described below.

[0034] (1) Base material 2 First, the substrate provided in the article disclosed herein preferably has at least its surface made of ceramic. In the first embodiment, the substrate 2 is made of ceramic. In this specification and claims, "ceramics" (hereinafter also referred to as "ceramic components") refers to inorganic compounds, not limited to oxides, and may be inorganic compounds that do not fall under the category of glass (amorphous structure). Furthermore, the term "made of ceramics" means that the ceramic component is the component that is most abundant by weight among the components constituting the substrate. Such a substrate may contain 95% by weight or more, 97% by weight or more, or 99% by weight or more of the ceramic component. Components other than the ceramic component may include, for example, various metallic and non-metallic elements as unavoidable impurities. Examples of such ceramic components include Al2O3, MgO, BeO, ZrO2, TiO2, Y2O3, mullite, forsterite, steatite, boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), and boehmite (AlOOH). These may be used singly or in combination. The average thickness of the substrate 2 (i.e., the width in the X direction in FIG. 1) is not particularly limited and may be within the range of 0.1 mm to 1 mm, for example. In this specification and claims, the term "average thickness" typically refers to the average value of the shortest distance between the upper and lower surfaces of a substrate, film, or layer (e.g., two surfaces in the X direction in FIG. 1) measured at three random points under a microscope. The substrate of the article disclosed herein may be made of a metal material such as Cu (copper) or W (tungsten).

[0035] (2) Glaze layer 3 The glaze layer 3 may be formed from a conventionally known glaze used in this type of technology. Examples of glazes include alkali-MgO-CaO-Fe2O3-Al2O3-SiO2 glazes and alkali-ZnO-Al2O3-SiO2 glazes. The glazes used in the examples described below are examples of such glazes. Here, the term "alkali" refers to an oxide of an alkali metal element, such as Na2O. While not intended to be particularly restrictive, many glazes contain such alkaline components, and the alkaline components are formed when an alkaline solution breaks the Si-O bond to form HSiO3 - and SiO3 2- Since the glaze layer may induce a reaction that generates the above, the glaze layer may be considered to have poor alkali resistance. Note that, since the technology disclosed herein relates to a glass former, a detailed description of the method for preparing the glaze will be omitted. The average value of the thickness of the glaze layer 3 (i.e., the width in the X direction in FIG. 1) (i.e., the average thickness of the glaze layer 3) is not particularly limited, and can be, for example, within a range of 100 nm to 5000 nm. Note that a substrate on which the glaze layer 3 has been formed in advance can also be used.

[0036] (3) Glass membrane 4 The glass film 4 is formed from any of the glass formers disclosed herein. The glass formers disclosed herein contain rare earth elements, which tend to have high oxygen affinity. Therefore, it is thought that the rare earth elements are doped into the glass matrix during glass film formation (specifically, during firing), thereby tightening the glass network structure. Furthermore, the rare earth oxides in the glass matrix remain and form a film even after other components are eluted by exposure to alkaline solution. These factors are thought to effectively prevent alkaline components from penetrating into the glass matrix.

[0037] The average value of the thickness (i.e., width in the X direction in FIG. 1 ) of the glass film 4 (i.e., average thickness of the glass film 4) is not particularly limited. For example, from the viewpoint of favorably exhibiting the color and texture of the decorative film provided on the article, it is preferably within a range of 20 nm to 500 nm, more preferably 20 nm to 150 nm.

[0038] (4) Decorative Film 5 The decorative film 5 may be formed from a conventionally known decorative composition used in this type of technology. Examples of decorative compositions include Pt-Si-Bi-based decorative compositions and Au-Si-Bi-based decorative compositions. The compositions used in the examples described below are examples of such compositions. Since the technology disclosed herein relates to glass formers, detailed explanations of the composition and preparation method of the decorative composition will be omitted. The average thickness of the decorative film 5 (i.e., the width in the X direction in FIG. 1 ) (i.e., the average thickness of the decorative film 5) is not particularly limited and can be, for example, within the range of 50 nm to 200 nm.

[0039] <Production method of the article> Next, a method for manufacturing the article 1 will be described, but it is not intended that the manufacturing method be limited to the following method. Steps can be added or deleted as needed. Furthermore, the order of the steps can be changed as needed. First, a substrate 2 is prepared. Then, a glaze is applied to the surface of the substrate 2, dried at a predetermined temperature (e.g., about 50°C to 100°C), and fired at a predetermined temperature (e.g., about 900°C to 1300°C) for a predetermined time (e.g., about 10 to 30 minutes). A substrate with a pre-applied glaze layer can also be used. Next, a glass former disclosed herein is applied to the surface of the fired glaze, dried at a predetermined temperature (e.g., about 50°C to 100°C), and fired at a predetermined temperature (e.g., about 600°C to 1000°C) for a predetermined time (e.g., about 10 to 30 minutes). Subsequently, a decorative composition is applied to the surface of the fired glass former, dried at a predetermined temperature (e.g., about 60°C), and fired at a predetermined temperature (e.g., about 700°C to 800°C) for a predetermined time (e.g., about 10 to 30 minutes), thereby producing an article 1.

[0040] The article disclosed herein can be, for example, tableware. Tableware is expected to be immersed in, for example, an alkaline detergent, and is therefore a suitable target for applying the technology disclosed herein.

[0041] <Other embodiments> One embodiment (first embodiment) of the article disclosed herein has been described above. Note that the above embodiment shows an example to which the technology disclosed herein is applied, and is not intended to limit the technology disclosed herein.

[0042] For example, FIG. 2 is a schematic diagram illustrating the cross-sectional structure of an article according to a second embodiment. As shown in FIG. 2, the article 10 according to the second embodiment includes a substrate 12, a glaze layer 13 formed on the substrate, a decorative film 15 formed on the glaze layer, and a glass film 14 formed from any of the glass formers disclosed herein and disposed on the decorative film. Thus, the article 10 having the glass film 14 on the decorative film 15 protects the glaze layer 13 with its excellent alkali resistance, even when exposed to an alkaline solution, thereby effectively preventing peeling of the decorative film 15. Furthermore, disposing the glass film 14 near the surface of the article 10 is preferable because it can impart a gloss (luster) to the article 10. Note that, like the article 1, the glass former disclosed herein contains a rare earth element, and thus the article 10 is characterized in that the rare earth element is present in the glass film 14 in the greatest amount among the substrate 12, glaze layer 13, decorative film 15, and glass film 14. The base material 12, the glaze layer 13, the glass film 14, and the decorative film 15 may have the same configurations as the base material 2, the glaze layer 3, the glass film 4, and the decorative film 5. The article 10 may be manufactured by, for example, switching the order of forming the glass film and the decorative film in the manufacturing method of the article 1 described above.

[0043] For example, Fig. 3 is a schematic diagram illustrating the cross-sectional structure of an article according to a third embodiment. As shown in Fig. 3, the article 20 according to the third embodiment includes a substrate 22, a glaze layer 23 formed on the substrate, a decorative film 25 formed on the glaze layer, and glass films 24a, 24b formed from any of the glass-forming agents disclosed herein, the glass films 24a, 24b existing between the glaze layer and the decorative film and on the decorative film. In this way, an article including the glass films 24a, 24b between the glaze layer and the decorative film and on the decorative film protects the glaze layer 23 from above and below by the highly alkali-resistant glass films 24a, 24b, even when exposed to an alkaline solution, thereby more effectively preventing peeling of the decorative film 25. Similar to article 1, the glass former disclosed herein contains rare earth elements, and thus article 20 is characterized in that, among substrate 22, glaze layer 23, decorative film 25, and glass films 24a and 24b, rare earth elements are present in the largest amounts in glass films 24a and 24b. The configurations of substrate 22, glaze layer 23, glass films 24a and 24b, and decorative film 25 can be similar to those of substrate 2, glaze layer 3, glass film 4, and decorative film 5, respectively. Article 20 can be manufactured with reference to the manufacturing method of article 1 described above.

[0044] Furthermore, for example, the articles according to the first to third embodiments above include only a substrate, a glaze layer, a glass film, and a decorative film, but are not limited thereto and may further include other layers (or films). The shape of the article can be appropriately changed depending on the intended use.

[0045] [Test example] Test examples relating to the technology disclosed herein will be described below, but it is not intended that the technology disclosed herein be limited to such test examples.

[0046] 1. Sample Preparation <Preparation of Glass Forming Agent> In this test example, eight types of glass formers with different glass matrix element contents were prepared (Examples 1 to 8). The content of each element in Examples 1 to 8 is shown in Table 1. Note that each value in Table 1 indicates the content (mol%) of each element when the total number of moles of glass matrix elements contained in the glass former is taken as 100 mol%. The glass formers in this test example were prepared by blending various raw materials (see "Raw Materials for Each Element") in an ointment jar and mixing them for 2 minutes at 1800 rpm using a Thinky Mixer (product name: Rotating and Revolutioning Awatori Rentaro). The glass formers were prepared by adding a diluent (WA Oil) manufactured by Noritake Co., Ltd., as needed, so that the viscosity at 25°C and 100 rpm (measured using a Brookfield DV viscometer) was approximately 10 to 15 mPa·s.

[0047] <Preparation of decorative composition> Next, a decorative composition was prepared. In this test example, the decorative composition was prepared to have the following composition by weight, where the total weight of the metal elements and metalloid elements contained in the decorative composition is 100% by weight: Pt; 86.1% by weight, Si; 5.9% by weight, and Bi; 8.0% by weight. The decorative composition in this test example was prepared by blending various raw materials (see "Raw Materials for Each Element") in an ointment jar and mixing for 2 minutes at 1800 rpm using a Thinky Mixer (product name: Rotating and Revolving Awatori Mixer). The decorative composition was prepared by adding a diluent (WA Oil) manufactured by Noritake Co., Ltd., as needed, so that the viscosity at 25°C and 100 rpm (measured with a Brookfield DV viscometer) was approximately 10-15 mPa·s.

[0048] <Raw materials for each element> The raw materials of the elements contained in the glass former and decorative composition of this test example are as follows: Commercially available raw materials were used as the raw materials below. Si:Si resinate (silicon resin acid salt) Bi: Bi resinate (bismuth resinate) Sm: Sm resinate (samarium resinate) Y: Y resinate (yttrium resinate) Pr: Pr resinate (praseodymium resinate) Nd:Nd resinate (neodymium resinate) Pt: Pt resinate (platinum resin sulfide balsam)

[0049] <Sample Preparation> In this test example, for each example, a sample having a structure in which the substrate, glaze layer, glass film, and decorative film are laminated in this order as shown in Figure 1 (hereinafter also simply referred to as a "base coat sample"), and a sample having a structure in which the substrate, glaze layer, decorative film, and glass film are laminated in this order as shown in Figure 2 (hereinafter also simply referred to as a "top coat sample") were prepared. The methods for preparing the top coat sample and the base coat sample are described below. First, a white porcelain plate (length: 15 mm, width: 15 mm, thickness: 20 mm) with a glaze layer formed on it was prepared. The glaze used had the following composition (molar oxide ratio): 70.8 mol% SiO2, 16.4 mol% Al2O3, 0.1 mol% Fe2O3, 4.2 mol% CaO, 4.0 mol% MgO, 3.4 mol% KO, 0.6 mol% Na2O, and 0.5 mol% ZnO.

[0050] Next, for the top coat sample, the decorative composition prepared as described above was applied to the glaze layer, dried at 60°C for 60 minutes, and then fired at 800°C for 10 minutes. The glass former prepared as described above was applied to the glaze layer and dried at 60°C for 60 minutes. For the base coat sample, the order of application of the glass former and decorative composition was reversed. The glass former and decorative composition were applied using a spin coater (Mikasa Corporation) called Opticoat MS-A-150, with spin conditions set at 5000 rpm for 10 seconds. The resulting laminate was then dried on a hot plate heated to 60°C for 1 hour and then fired at 800°C for 10 minutes to obtain top coat sample and base coat sample. Here, the cross sections of each top and bottom sample after firing were observed using an FE-SEM (SU-8200, manufactured by Hitachi High-Technologies Corporation). The results showed that the average thickness of the glaze layer was 1000nm to 3000nm, the average thickness of the decorative film was 100nm to 200nm, and the average thickness of the glass film was within the range of 50nm to 150nm.

[0051] 2.Evaluation Test <Alkali resistance evaluation> In this test, each sample was immersed for 30 minutes in a 0.5 wt. % Na2CO3 aqueous solution (3 L) that had been heated to 100°C and boiled. The immersion samples were then rinsed with water and subjected to a scratch test in which zircon paper was rubbed against the sample 10 times to observe whether the decorative film had been damaged. The immersion time was extended in 30-minute increments, and the maximum immersion time during which at least 30% of the decorative film remained was considered the "durability time (h)." A durability time of 1.0 hour or longer was considered to have sufficient alkali resistance, and a durability time of 1.5 hours or longer was considered to have excellent alkali resistance. The results for each base coat sample are shown in the corresponding column in Table 1. Although not explicitly stated in Table 1, the top coat samples in Examples 2 to 4 and 6 to 8 were confirmed to have excellent alkali resistance (i.e., a durability time of 1.0 hour or longer). Furthermore, although not specified in Table 1, samples without a glass film (i.e., samples in which the base material, glaze layer, and decorative film were layered in this order) had a durability time of less than 0.5 hours, confirming that they did not have sufficient alkali resistance.

[0052] Although detailed data are not presented, the base coat samples and top coat samples for Examples 2-4 and 6-8 were subjected to FIB (Focused Ion Beam) processing to thin each sample. Subsequently, elemental mapping and line analysis were performed on the cross sections of the thin sections using FESEM-EDX. These measurements were performed using a field-emission scanning electron microscope (Hitachi High-Tech Corporation: SU8230) and an energy-dispersive X-ray analyzer (Horiba, Ltd.: X-Max80 detector, software: EMAX ENERGY version 2.04) to obtain a qualitative analysis chart of each element on the surface of the measurement sample for each example. The thinning and measurement conditions were determined based on the equipment catalog. As a result, of the four layers of each sample—base material, glaze layer, glass film, and decorative film—the glass film contained the highest amount of rare earth elements.

[0053] [Table 1]

[0054] As shown in Table 1, Examples 2 to 4 and 6 to 8, which included glass films formed from glass formers containing Si and rare earth elements in a range of 1 to 70 mol % (where the total number of moles of the glass matrix elements is 100 mol %), had a durability of 1.0 hour or more, demonstrating sufficient alkali resistance, compared to Example 1, which included a glass film formed from a glass former not containing rare earth elements as glass matrix elements. On the other hand, Example 5, which included a glass film formed from a glass former with a rare earth element content outside the range of 1 to 70 mol %, had a durability of less than 1.0 hour, demonstrating insufficient alkali resistance. Furthermore, Examples 2 and 3, which included glass films formed from a glass former with a rare earth element content in a range of 3 to 30 mol %, were confirmed to have superior alkali resistance. Furthermore, Example 7, which included a glass film formed from a glass former containing praseodymium among the rare earth elements, was confirmed to have particularly excellent alkali resistance. The above results show that the glass former disclosed herein can suitably improve the alkali resistance of a decorative film formed on a glaze layer of a substrate to which a glaze layer has been applied.

[0055] While specific examples of the technology disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. [Explanation of symbols]

[0056] 1,10,20 Goods 2,12,22 Base material 3,13,23 Glaze layer 4,14,24a,24b Glass membrane 5,15,25 Decorative membrane

Claims

1. A glass former that forms a glass film for protecting a decorative film formed on a glaze layer of a substrate to which a glaze layer has been applied, the glass former comprises a glass matrix element; The glass matrix elements include at least Si, Bi, and a rare earth element, the rare earth element is at least one selected from the group consisting of Sm, Y, Pr, and Nd; a glass former, wherein, when the total number of moles of the glass matrix elements is taken as 100 mol%, the content of the Si is 40 mol% to 85 mol%, the content of the Bi is 7 mol% to 15 mol%, and the content of the rare earth element is 1 mol% to 70 mol%.

2. 2. The glass former according to claim 1, wherein the content of said rare earth element is 3 mol % to 30 mol % when the total number of moles of said glass matrix elements is 100 mol %.

3. 3. The glass former according to claim 1, wherein at least the surface of the substrate is made of ceramic.

4. A substrate; a glaze layer formed on the base material; a decorative film formed on the glaze layer; A glass film formed by the glass forming agent according to any one of claims 1 to 3, the glass film being present between the glaze layer and the decorative film; An article comprising: The article, wherein the rare earth element is present in the largest amount in the glass film among the base material, the glaze layer, the decorative film, and the glass film.

5. The article of claim 4, wherein the glass film has an average thickness of 20 nm to 500 nm.

6. The article according to claim 4 or 5, wherein at least the surface of the substrate is made of ceramic.

7. The article according to any one of claims 4 to 6, which constitutes tableware.

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